OpenCloudOS-Kernel/fs/btrfs/file.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/falloc.h>
#include <linux/writeback.h>
#include <linux/compat.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/btrfs.h>
#include <linux/uio.h>
#include <linux/iversion.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "tree-log.h"
#include "locking.h"
#include "volumes.h"
Btrfs: rework qgroup accounting Currently qgroups account for space by intercepting delayed ref updates to fs trees. It does this by adding sequence numbers to delayed ref updates so that it can figure out how the tree looked before the update so we can adjust the counters properly. The problem with this is that it does not allow delayed refs to be merged, so if you say are defragging an extent with 5k snapshots pointing to it we will thrash the delayed ref lock because we need to go back and manually merge these things together. Instead we want to process quota changes when we know they are going to happen, like when we first allocate an extent, we free a reference for an extent, we add new references etc. This patch accomplishes this by only adding qgroup operations for real ref changes. We only modify the sequence number when we need to lookup roots for bytenrs, this reduces the amount of churn on the sequence number and allows us to merge delayed refs as we add them most of the time. This patch encompasses a bunch of architectural changes 1) qgroup ref operations: instead of tracking qgroup operations through the delayed refs we simply add new ref operations whenever we notice that we need to when we've modified the refs themselves. 2) tree mod seq: we no longer have this separation of major/minor counters. this makes the sequence number stuff much more sane and we can remove some locking that was needed to protect the counter. 3) delayed ref seq: we now read the tree mod seq number and use that as our sequence. This means each new delayed ref doesn't have it's own unique sequence number, rather whenever we go to lookup backrefs we inc the sequence number so we can make sure to keep any new operations from screwing up our world view at that given point. This allows us to merge delayed refs during runtime. With all of these changes the delayed ref stuff is a little saner and the qgroup accounting stuff no longer goes negative in some cases like it was before. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-05-14 08:30:47 +08:00
#include "qgroup.h"
#include "compression.h"
#include "delalloc-space.h"
#include "reflink.h"
#include "subpage.h"
static struct kmem_cache *btrfs_inode_defrag_cachep;
/*
* when auto defrag is enabled we
* queue up these defrag structs to remember which
* inodes need defragging passes
*/
struct inode_defrag {
struct rb_node rb_node;
/* objectid */
u64 ino;
/*
* transid where the defrag was added, we search for
* extents newer than this
*/
u64 transid;
/* root objectid */
u64 root;
/* last offset we were able to defrag */
u64 last_offset;
/* if we've wrapped around back to zero once already */
int cycled;
};
static int __compare_inode_defrag(struct inode_defrag *defrag1,
struct inode_defrag *defrag2)
{
if (defrag1->root > defrag2->root)
return 1;
else if (defrag1->root < defrag2->root)
return -1;
else if (defrag1->ino > defrag2->ino)
return 1;
else if (defrag1->ino < defrag2->ino)
return -1;
else
return 0;
}
/* pop a record for an inode into the defrag tree. The lock
* must be held already
*
* If you're inserting a record for an older transid than an
* existing record, the transid already in the tree is lowered
*
* If an existing record is found the defrag item you
* pass in is freed
*/
static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
struct inode_defrag *defrag)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct inode_defrag *entry;
struct rb_node **p;
struct rb_node *parent = NULL;
int ret;
p = &fs_info->defrag_inodes.rb_node;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct inode_defrag, rb_node);
ret = __compare_inode_defrag(defrag, entry);
if (ret < 0)
p = &parent->rb_left;
else if (ret > 0)
p = &parent->rb_right;
else {
/* if we're reinserting an entry for
* an old defrag run, make sure to
* lower the transid of our existing record
*/
if (defrag->transid < entry->transid)
entry->transid = defrag->transid;
if (defrag->last_offset > entry->last_offset)
entry->last_offset = defrag->last_offset;
return -EEXIST;
}
}
set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
rb_link_node(&defrag->rb_node, parent, p);
rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
return 0;
}
static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
{
if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
return 0;
if (btrfs_fs_closing(fs_info))
return 0;
return 1;
}
/*
* insert a defrag record for this inode if auto defrag is
* enabled
*/
int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode)
{
struct btrfs_root *root = inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct inode_defrag *defrag;
u64 transid;
int ret;
if (!__need_auto_defrag(fs_info))
return 0;
if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
return 0;
if (trans)
transid = trans->transid;
else
transid = inode->root->last_trans;
defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
if (!defrag)
return -ENOMEM;
defrag->ino = btrfs_ino(inode);
defrag->transid = transid;
defrag->root = root->root_key.objectid;
spin_lock(&fs_info->defrag_inodes_lock);
if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
/*
* If we set IN_DEFRAG flag and evict the inode from memory,
* and then re-read this inode, this new inode doesn't have
* IN_DEFRAG flag. At the case, we may find the existed defrag.
*/
ret = __btrfs_add_inode_defrag(inode, defrag);
if (ret)
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
} else {
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
spin_unlock(&fs_info->defrag_inodes_lock);
return 0;
}
/*
* Requeue the defrag object. If there is a defrag object that points to
* the same inode in the tree, we will merge them together (by
* __btrfs_add_inode_defrag()) and free the one that we want to requeue.
*/
static void btrfs_requeue_inode_defrag(struct btrfs_inode *inode,
struct inode_defrag *defrag)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
int ret;
if (!__need_auto_defrag(fs_info))
goto out;
/*
* Here we don't check the IN_DEFRAG flag, because we need merge
* them together.
*/
spin_lock(&fs_info->defrag_inodes_lock);
ret = __btrfs_add_inode_defrag(inode, defrag);
spin_unlock(&fs_info->defrag_inodes_lock);
if (ret)
goto out;
return;
out:
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
/*
* pick the defragable inode that we want, if it doesn't exist, we will get
* the next one.
*/
static struct inode_defrag *
btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
{
struct inode_defrag *entry = NULL;
struct inode_defrag tmp;
struct rb_node *p;
struct rb_node *parent = NULL;
int ret;
tmp.ino = ino;
tmp.root = root;
spin_lock(&fs_info->defrag_inodes_lock);
p = fs_info->defrag_inodes.rb_node;
while (p) {
parent = p;
entry = rb_entry(parent, struct inode_defrag, rb_node);
ret = __compare_inode_defrag(&tmp, entry);
if (ret < 0)
p = parent->rb_left;
else if (ret > 0)
p = parent->rb_right;
else
goto out;
}
if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
parent = rb_next(parent);
if (parent)
entry = rb_entry(parent, struct inode_defrag, rb_node);
else
entry = NULL;
}
out:
if (entry)
rb_erase(parent, &fs_info->defrag_inodes);
spin_unlock(&fs_info->defrag_inodes_lock);
return entry;
}
void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
{
struct inode_defrag *defrag;
struct rb_node *node;
spin_lock(&fs_info->defrag_inodes_lock);
node = rb_first(&fs_info->defrag_inodes);
while (node) {
rb_erase(node, &fs_info->defrag_inodes);
defrag = rb_entry(node, struct inode_defrag, rb_node);
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
cond_resched_lock(&fs_info->defrag_inodes_lock);
node = rb_first(&fs_info->defrag_inodes);
}
spin_unlock(&fs_info->defrag_inodes_lock);
}
#define BTRFS_DEFRAG_BATCH 1024
static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
struct inode_defrag *defrag)
{
struct btrfs_root *inode_root;
struct inode *inode;
struct btrfs_ioctl_defrag_range_args range;
int num_defrag;
int ret;
/* get the inode */
inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
if (IS_ERR(inode_root)) {
ret = PTR_ERR(inode_root);
goto cleanup;
}
inode = btrfs_iget(fs_info->sb, defrag->ino, inode_root);
btrfs_put_root(inode_root);
if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
goto cleanup;
}
/* do a chunk of defrag */
clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
memset(&range, 0, sizeof(range));
range.len = (u64)-1;
range.start = defrag->last_offset;
sb_start_write(fs_info->sb);
num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
BTRFS_DEFRAG_BATCH);
sb_end_write(fs_info->sb);
/*
* if we filled the whole defrag batch, there
* must be more work to do. Queue this defrag
* again
*/
if (num_defrag == BTRFS_DEFRAG_BATCH) {
defrag->last_offset = range.start;
btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
} else if (defrag->last_offset && !defrag->cycled) {
/*
* we didn't fill our defrag batch, but
* we didn't start at zero. Make sure we loop
* around to the start of the file.
*/
defrag->last_offset = 0;
defrag->cycled = 1;
btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
} else {
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
iput(inode);
return 0;
cleanup:
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
return ret;
}
/*
* run through the list of inodes in the FS that need
* defragging
*/
int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
{
struct inode_defrag *defrag;
u64 first_ino = 0;
u64 root_objectid = 0;
atomic_inc(&fs_info->defrag_running);
while (1) {
/* Pause the auto defragger. */
if (test_bit(BTRFS_FS_STATE_REMOUNTING,
&fs_info->fs_state))
break;
if (!__need_auto_defrag(fs_info))
break;
/* find an inode to defrag */
defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
first_ino);
if (!defrag) {
if (root_objectid || first_ino) {
root_objectid = 0;
first_ino = 0;
continue;
} else {
break;
}
}
first_ino = defrag->ino + 1;
root_objectid = defrag->root;
__btrfs_run_defrag_inode(fs_info, defrag);
}
atomic_dec(&fs_info->defrag_running);
/*
* during unmount, we use the transaction_wait queue to
* wait for the defragger to stop
*/
wake_up(&fs_info->transaction_wait);
return 0;
}
/* simple helper to fault in pages and copy. This should go away
* and be replaced with calls into generic code.
*/
static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
struct page **prepared_pages,
struct iov_iter *i)
{
size_t copied = 0;
size_t total_copied = 0;
int pg = 0;
int offset = offset_in_page(pos);
while (write_bytes > 0) {
size_t count = min_t(size_t,
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
PAGE_SIZE - offset, write_bytes);
struct page *page = prepared_pages[pg];
/*
* Copy data from userspace to the current page
*/
copied = copy_page_from_iter_atomic(page, offset, count, i);
/* Flush processor's dcache for this page */
flush_dcache_page(page);
/*
* if we get a partial write, we can end up with
* partially up to date pages. These add
* a lot of complexity, so make sure they don't
* happen by forcing this copy to be retried.
*
* The rest of the btrfs_file_write code will fall
* back to page at a time copies after we return 0.
*/
if (unlikely(copied < count)) {
if (!PageUptodate(page)) {
iov_iter_revert(i, copied);
copied = 0;
}
if (!copied)
break;
}
write_bytes -= copied;
total_copied += copied;
offset += copied;
if (offset == PAGE_SIZE) {
pg++;
offset = 0;
}
}
return total_copied;
}
/*
* unlocks pages after btrfs_file_write is done with them
*/
static void btrfs_drop_pages(struct page **pages, size_t num_pages)
{
size_t i;
for (i = 0; i < num_pages; i++) {
/* page checked is some magic around finding pages that
* have been modified without going through btrfs_set_page_dirty
mm: non-atomically mark page accessed during page cache allocation where possible aops->write_begin may allocate a new page and make it visible only to have mark_page_accessed called almost immediately after. Once the page is visible the atomic operations are necessary which is noticable overhead when writing to an in-memory filesystem like tmpfs but should also be noticable with fast storage. The objective of the patch is to initialse the accessed information with non-atomic operations before the page is visible. The bulk of filesystems directly or indirectly use grab_cache_page_write_begin or find_or_create_page for the initial allocation of a page cache page. This patch adds an init_page_accessed() helper which behaves like the first call to mark_page_accessed() but may called before the page is visible and can be done non-atomically. The primary APIs of concern in this care are the following and are used by most filesystems. find_get_page find_lock_page find_or_create_page grab_cache_page_nowait grab_cache_page_write_begin All of them are very similar in detail to the patch creates a core helper pagecache_get_page() which takes a flags parameter that affects its behavior such as whether the page should be marked accessed or not. Then old API is preserved but is basically a thin wrapper around this core function. Each of the filesystems are then updated to avoid calling mark_page_accessed when it is known that the VM interfaces have already done the job. There is a slight snag in that the timing of the mark_page_accessed() has now changed so in rare cases it's possible a page gets to the end of the LRU as PageReferenced where as previously it might have been repromoted. This is expected to be rare but it's worth the filesystem people thinking about it in case they see a problem with the timing change. It is also the case that some filesystems may be marking pages accessed that previously did not but it makes sense that filesystems have consistent behaviour in this regard. The test case used to evaulate this is a simple dd of a large file done multiple times with the file deleted on each iterations. The size of the file is 1/10th physical memory to avoid dirty page balancing. In the async case it will be possible that the workload completes without even hitting the disk and will have variable results but highlight the impact of mark_page_accessed for async IO. The sync results are expected to be more stable. The exception is tmpfs where the normal case is for the "IO" to not hit the disk. The test machine was single socket and UMA to avoid any scheduling or NUMA artifacts. Throughput and wall times are presented for sync IO, only wall times are shown for async as the granularity reported by dd and the variability is unsuitable for comparison. As async results were variable do to writback timings, I'm only reporting the maximum figures. The sync results were stable enough to make the mean and stddev uninteresting. The performance results are reported based on a run with no profiling. Profile data is based on a separate run with oprofile running. async dd 3.15.0-rc3 3.15.0-rc3 vanilla accessed-v2 ext3 Max elapsed 13.9900 ( 0.00%) 11.5900 ( 17.16%) tmpfs Max elapsed 0.5100 ( 0.00%) 0.4900 ( 3.92%) btrfs Max elapsed 12.8100 ( 0.00%) 12.7800 ( 0.23%) ext4 Max elapsed 18.6000 ( 0.00%) 13.3400 ( 28.28%) xfs Max elapsed 12.5600 ( 0.00%) 2.0900 ( 83.36%) The XFS figure is a bit strange as it managed to avoid a worst case by sheer luck but the average figures looked reasonable. samples percentage ext3 86107 0.9783 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext3 23833 0.2710 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext3 5036 0.0573 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed ext4 64566 0.8961 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext4 5322 0.0713 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext4 2869 0.0384 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 62126 1.7675 vmlinux-3.15.0-rc4-vanilla mark_page_accessed xfs 1904 0.0554 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 103 0.0030 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed btrfs 10655 0.1338 vmlinux-3.15.0-rc4-vanilla mark_page_accessed btrfs 2020 0.0273 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed btrfs 587 0.0079 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed tmpfs 59562 3.2628 vmlinux-3.15.0-rc4-vanilla mark_page_accessed tmpfs 1210 0.0696 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed tmpfs 94 0.0054 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed [akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-05 07:10:31 +08:00
* clear it here. There should be no need to mark the pages
* accessed as prepare_pages should have marked them accessed
* in prepare_pages via find_or_create_page()
*/
ClearPageChecked(pages[i]);
unlock_page(pages[i]);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
put_page(pages[i]);
}
}
/*
* After btrfs_copy_from_user(), update the following things for delalloc:
* - Mark newly dirtied pages as DELALLOC in the io tree.
* Used to advise which range is to be written back.
* - Mark modified pages as Uptodate/Dirty and not needing COW fixup
* - Update inode size for past EOF write
*/
int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
size_t num_pages, loff_t pos, size_t write_bytes,
struct extent_state **cached, bool noreserve)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
int err = 0;
int i;
u64 num_bytes;
u64 start_pos;
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
loff_t isize = i_size_read(&inode->vfs_inode);
Btrfs: fix reported number of inode blocks after buffered append writes The patch from commit a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks") introduced a regression where if we do a buffered write starting at position equal to or greater than the file's size and then stat(2) the file before writeback is triggered, the number of used blocks does not change (unless there's a prealloc/unwritten extent). Example: $ xfs_io -f -c "pwrite -S 0xab 0 64K" foobar $ du -h foobar 0 foobar $ sync $ du -h foobar 64K foobar The first version of that patch didn't had this regression and the second version, which was the one committed, was made only to address some performance regression detected by the intel test robots using fs_mark. This fixes the regression by setting the new delaloc bit in the range, and doing it at btrfs_dirty_pages() while setting the regular dealloc bit as well, so that this way we set both bits at once avoiding navigation of the inode's io tree twice. Doing it at btrfs_dirty_pages() is also the most meaninful place, as we should set the new dellaloc bit when if we set the delalloc bit, which happens only if we copied bytes into the pages at __btrfs_buffered_write(). This was making some of LTP's du tests fail, which can be quickly run using a command line like the following: $ ./runltp -q -p -l /ltp.log -f commands -s du -d /mnt Fixes: a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-04 08:16:59 +08:00
unsigned int extra_bits = 0;
if (write_bytes == 0)
return 0;
if (noreserve)
extra_bits |= EXTENT_NORESERVE;
start_pos = round_down(pos, fs_info->sectorsize);
num_bytes = round_up(write_bytes + pos - start_pos,
fs_info->sectorsize);
ASSERT(num_bytes <= U32_MAX);
end_of_last_block = start_pos + num_bytes - 1;
Btrfs: fix reported number of inode blocks after buffered append writes The patch from commit a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks") introduced a regression where if we do a buffered write starting at position equal to or greater than the file's size and then stat(2) the file before writeback is triggered, the number of used blocks does not change (unless there's a prealloc/unwritten extent). Example: $ xfs_io -f -c "pwrite -S 0xab 0 64K" foobar $ du -h foobar 0 foobar $ sync $ du -h foobar 64K foobar The first version of that patch didn't had this regression and the second version, which was the one committed, was made only to address some performance regression detected by the intel test robots using fs_mark. This fixes the regression by setting the new delaloc bit in the range, and doing it at btrfs_dirty_pages() while setting the regular dealloc bit as well, so that this way we set both bits at once avoiding navigation of the inode's io tree twice. Doing it at btrfs_dirty_pages() is also the most meaninful place, as we should set the new dellaloc bit when if we set the delalloc bit, which happens only if we copied bytes into the pages at __btrfs_buffered_write(). This was making some of LTP's du tests fail, which can be quickly run using a command line like the following: $ ./runltp -q -p -l /ltp.log -f commands -s du -d /mnt Fixes: a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-04 08:16:59 +08:00
/*
* The pages may have already been dirty, clear out old accounting so
* we can set things up properly
*/
clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
0, 0, cached);
err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
extra_bits, cached);
if (err)
return err;
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-12 04:12:44 +08:00
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
for (i = 0; i < num_pages; i++) {
struct page *p = pages[i];
btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
ClearPageChecked(p);
btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes);
}
/*
* we've only changed i_size in ram, and we haven't updated
* the disk i_size. There is no need to log the inode
* at this time.
*/
if (end_pos > isize)
i_size_write(&inode->vfs_inode, end_pos);
return 0;
}
/*
* this drops all the extents in the cache that intersect the range
* [start, end]. Existing extents are split as required.
*/
void btrfs_drop_extent_cache(struct btrfs_inode *inode, u64 start, u64 end,
int skip_pinned)
{
struct extent_map *em;
struct extent_map *split = NULL;
struct extent_map *split2 = NULL;
struct extent_map_tree *em_tree = &inode->extent_tree;
u64 len = end - start + 1;
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
u64 gen;
int ret;
int testend = 1;
unsigned long flags;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
int compressed = 0;
2013-04-06 04:51:15 +08:00
bool modified;
WARN_ON(end < start);
if (end == (u64)-1) {
len = (u64)-1;
testend = 0;
}
while (1) {
int no_splits = 0;
2013-04-06 04:51:15 +08:00
modified = false;
if (!split)
split = alloc_extent_map();
if (!split2)
split2 = alloc_extent_map();
if (!split || !split2)
no_splits = 1;
write_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, len);
if (!em) {
write_unlock(&em_tree->lock);
break;
}
flags = em->flags;
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
gen = em->generation;
if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
if (testend && em->start + em->len >= start + len) {
free_extent_map(em);
write_unlock(&em_tree->lock);
break;
}
start = em->start + em->len;
if (testend)
len = start + len - (em->start + em->len);
free_extent_map(em);
write_unlock(&em_tree->lock);
continue;
}
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
clear_bit(EXTENT_FLAG_PINNED, &em->flags);
clear_bit(EXTENT_FLAG_LOGGING, &flags);
2013-04-06 04:51:15 +08:00
modified = !list_empty(&em->list);
if (no_splits)
goto next;
if (em->start < start) {
split->start = em->start;
split->len = start - em->start;
if (em->block_start < EXTENT_MAP_LAST_BYTE) {
split->orig_start = em->orig_start;
split->block_start = em->block_start;
if (compressed)
split->block_len = em->block_len;
else
split->block_len = split->len;
split->orig_block_len = max(split->block_len,
em->orig_block_len);
split->ram_bytes = em->ram_bytes;
} else {
split->orig_start = split->start;
split->block_len = 0;
split->block_start = em->block_start;
split->orig_block_len = 0;
split->ram_bytes = split->len;
}
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
split->generation = gen;
split->flags = flags;
split->compress_type = em->compress_type;
Btrfs: more efficient btrfs_drop_extent_cache While droping extent map structures from the extent cache that cover our target range, we would remove each extent map structure from the red black tree and then add either 1 or 2 new extent map structures if the former extent map covered sections outside our target range. This change simply attempts to replace the existing extent map structure with a new one that covers the subsection we're not interested in, instead of doing a red black remove operation followed by an insertion operation. The number of elements in an inode's extent map tree can get very high for large files under random writes. For example, while running the following test: sysbench --test=fileio --file-num=1 --file-total-size=10G \ --file-test-mode=rndrw --num-threads=32 --file-block-size=32768 \ --max-requests=500000 --file-rw-ratio=2 [prepare|run] I captured the following histogram capturing the number of extent_map items in the red black tree while that test was running: Count: 122462 Range: 1.000 - 172231.000; Mean: 96415.831; Median: 101855.000; Stddev: 49700.981 Percentiles: 90th: 160120.000; 95th: 166335.000; 99th: 171070.000 1.000 - 5.231: 452 | 5.231 - 187.392: 87 | 187.392 - 585.911: 206 | 585.911 - 1827.438: 623 | 1827.438 - 5695.245: 1962 # 5695.245 - 17744.861: 6204 #### 17744.861 - 55283.764: 21115 ############ 55283.764 - 172231.000: 91813 ##################################################### Benchmark: sysbench --test=fileio --file-num=1 --file-total-size=10G --file-test-mode=rndwr \ --num-threads=64 --file-block-size=32768 --max-requests=0 --max-time=60 \ --file-io-mode=sync --file-fsync-freq=0 [prepare|run] Before this change: 122.1Mb/sec After this change: 125.07Mb/sec (averages of 5 test runs) Test machine: quad core intel i5-3570K, 32Gb of ram, SSD Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com>
2014-02-25 22:15:13 +08:00
replace_extent_mapping(em_tree, em, split, modified);
free_extent_map(split);
split = split2;
split2 = NULL;
}
if (testend && em->start + em->len > start + len) {
u64 diff = start + len - em->start;
split->start = start + len;
split->len = em->start + em->len - (start + len);
split->flags = flags;
split->compress_type = em->compress_type;
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
split->generation = gen;
if (em->block_start < EXTENT_MAP_LAST_BYTE) {
split->orig_block_len = max(em->block_len,
em->orig_block_len);
split->ram_bytes = em->ram_bytes;
if (compressed) {
split->block_len = em->block_len;
split->block_start = em->block_start;
split->orig_start = em->orig_start;
} else {
split->block_len = split->len;
split->block_start = em->block_start
+ diff;
split->orig_start = em->orig_start;
}
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
} else {
split->ram_bytes = split->len;
split->orig_start = split->start;
split->block_len = 0;
split->block_start = em->block_start;
split->orig_block_len = 0;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
}
Btrfs: more efficient btrfs_drop_extent_cache While droping extent map structures from the extent cache that cover our target range, we would remove each extent map structure from the red black tree and then add either 1 or 2 new extent map structures if the former extent map covered sections outside our target range. This change simply attempts to replace the existing extent map structure with a new one that covers the subsection we're not interested in, instead of doing a red black remove operation followed by an insertion operation. The number of elements in an inode's extent map tree can get very high for large files under random writes. For example, while running the following test: sysbench --test=fileio --file-num=1 --file-total-size=10G \ --file-test-mode=rndrw --num-threads=32 --file-block-size=32768 \ --max-requests=500000 --file-rw-ratio=2 [prepare|run] I captured the following histogram capturing the number of extent_map items in the red black tree while that test was running: Count: 122462 Range: 1.000 - 172231.000; Mean: 96415.831; Median: 101855.000; Stddev: 49700.981 Percentiles: 90th: 160120.000; 95th: 166335.000; 99th: 171070.000 1.000 - 5.231: 452 | 5.231 - 187.392: 87 | 187.392 - 585.911: 206 | 585.911 - 1827.438: 623 | 1827.438 - 5695.245: 1962 # 5695.245 - 17744.861: 6204 #### 17744.861 - 55283.764: 21115 ############ 55283.764 - 172231.000: 91813 ##################################################### Benchmark: sysbench --test=fileio --file-num=1 --file-total-size=10G --file-test-mode=rndwr \ --num-threads=64 --file-block-size=32768 --max-requests=0 --max-time=60 \ --file-io-mode=sync --file-fsync-freq=0 [prepare|run] Before this change: 122.1Mb/sec After this change: 125.07Mb/sec (averages of 5 test runs) Test machine: quad core intel i5-3570K, 32Gb of ram, SSD Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com>
2014-02-25 22:15:13 +08:00
if (extent_map_in_tree(em)) {
replace_extent_mapping(em_tree, em, split,
modified);
} else {
ret = add_extent_mapping(em_tree, split,
modified);
ASSERT(ret == 0); /* Logic error */
}
free_extent_map(split);
split = NULL;
}
next:
Btrfs: more efficient btrfs_drop_extent_cache While droping extent map structures from the extent cache that cover our target range, we would remove each extent map structure from the red black tree and then add either 1 or 2 new extent map structures if the former extent map covered sections outside our target range. This change simply attempts to replace the existing extent map structure with a new one that covers the subsection we're not interested in, instead of doing a red black remove operation followed by an insertion operation. The number of elements in an inode's extent map tree can get very high for large files under random writes. For example, while running the following test: sysbench --test=fileio --file-num=1 --file-total-size=10G \ --file-test-mode=rndrw --num-threads=32 --file-block-size=32768 \ --max-requests=500000 --file-rw-ratio=2 [prepare|run] I captured the following histogram capturing the number of extent_map items in the red black tree while that test was running: Count: 122462 Range: 1.000 - 172231.000; Mean: 96415.831; Median: 101855.000; Stddev: 49700.981 Percentiles: 90th: 160120.000; 95th: 166335.000; 99th: 171070.000 1.000 - 5.231: 452 | 5.231 - 187.392: 87 | 187.392 - 585.911: 206 | 585.911 - 1827.438: 623 | 1827.438 - 5695.245: 1962 # 5695.245 - 17744.861: 6204 #### 17744.861 - 55283.764: 21115 ############ 55283.764 - 172231.000: 91813 ##################################################### Benchmark: sysbench --test=fileio --file-num=1 --file-total-size=10G --file-test-mode=rndwr \ --num-threads=64 --file-block-size=32768 --max-requests=0 --max-time=60 \ --file-io-mode=sync --file-fsync-freq=0 [prepare|run] Before this change: 122.1Mb/sec After this change: 125.07Mb/sec (averages of 5 test runs) Test machine: quad core intel i5-3570K, 32Gb of ram, SSD Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com>
2014-02-25 22:15:13 +08:00
if (extent_map_in_tree(em))
remove_extent_mapping(em_tree, em);
write_unlock(&em_tree->lock);
/* once for us */
free_extent_map(em);
/* once for the tree*/
free_extent_map(em);
}
if (split)
free_extent_map(split);
if (split2)
free_extent_map(split2);
}
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
* that would be a good hint to the block allocator for this file.
*
* If an extent intersects the range but is not entirely inside the range
* it is either truncated or split. Anything entirely inside the range
* is deleted from the tree.
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
*
* Note: the VFS' inode number of bytes is not updated, it's up to the caller
* to deal with that. We set the field 'bytes_found' of the arguments structure
* with the number of allocated bytes found in the target range, so that the
* caller can update the inode's number of bytes in an atomic way when
* replacing extents in a range to avoid races with stat(2).
*/
int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_inode *inode,
struct btrfs_drop_extents_args *args)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct btrfs_ref ref = { 0 };
struct btrfs_key key;
struct btrfs_key new_key;
u64 ino = btrfs_ino(inode);
u64 search_start = args->start;
u64 disk_bytenr = 0;
u64 num_bytes = 0;
u64 extent_offset = 0;
u64 extent_end = 0;
u64 last_end = args->start;
int del_nr = 0;
int del_slot = 0;
int extent_type;
int recow;
int ret;
int modify_tree = -1;
int update_refs;
int found = 0;
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
int leafs_visited = 0;
struct btrfs_path *path = args->path;
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
args->bytes_found = 0;
args->extent_inserted = false;
/* Must always have a path if ->replace_extent is true */
ASSERT(!(args->replace_extent && !args->path));
if (!path) {
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
}
if (args->drop_cache)
btrfs_drop_extent_cache(inode, args->start, args->end - 1, 0);
if (args->start >= inode->disk_i_size && !args->replace_extent)
modify_tree = 0;
update_refs = (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root == fs_info->tree_root);
while (1) {
recow = 0;
ret = btrfs_lookup_file_extent(trans, root, path, ino,
search_start, modify_tree);
if (ret < 0)
break;
if (ret > 0 && path->slots[0] > 0 && search_start == args->start) {
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
if (key.objectid == ino &&
key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
ret = 0;
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
leafs_visited++;
next_slot:
leaf = path->nodes[0];
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
BUG_ON(del_nr > 0);
ret = btrfs_next_leaf(root, path);
if (ret < 0)
break;
if (ret > 0) {
ret = 0;
break;
}
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
leafs_visited++;
leaf = path->nodes[0];
recow = 1;
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
Btrfs: fix race leading to incorrect item deletion when dropping extents While running a stress test I got the following warning triggered: [191627.672810] ------------[ cut here ]------------ [191627.673949] WARNING: CPU: 8 PID: 8447 at fs/btrfs/file.c:779 __btrfs_drop_extents+0x391/0xa50 [btrfs]() (...) [191627.701485] Call Trace: [191627.702037] [<ffffffff8145f077>] dump_stack+0x4f/0x7b [191627.702992] [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2 [191627.704091] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb [191627.705380] [<ffffffffa0664499>] ? __btrfs_drop_extents+0x391/0xa50 [btrfs] [191627.706637] [<ffffffff8104b46d>] warn_slowpath_null+0x1a/0x1c [191627.707789] [<ffffffffa0664499>] __btrfs_drop_extents+0x391/0xa50 [btrfs] [191627.709155] [<ffffffff8115663c>] ? cache_alloc_debugcheck_after.isra.32+0x171/0x1d0 [191627.712444] [<ffffffff81155007>] ? kmemleak_alloc_recursive.constprop.40+0x16/0x18 [191627.714162] [<ffffffffa06570c9>] insert_reserved_file_extent.constprop.40+0x83/0x24e [btrfs] [191627.715887] [<ffffffffa065422b>] ? start_transaction+0x3bb/0x610 [btrfs] [191627.717287] [<ffffffffa065b604>] btrfs_finish_ordered_io+0x273/0x4e2 [btrfs] [191627.728865] [<ffffffffa065b888>] finish_ordered_fn+0x15/0x17 [btrfs] [191627.730045] [<ffffffffa067d688>] normal_work_helper+0x14c/0x32c [btrfs] [191627.731256] [<ffffffffa067d96a>] btrfs_endio_write_helper+0x12/0x14 [btrfs] [191627.732661] [<ffffffff81061119>] process_one_work+0x24c/0x4ae [191627.733822] [<ffffffff810615b0>] worker_thread+0x206/0x2c2 [191627.734857] [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f [191627.736052] [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f [191627.737349] [<ffffffff810669a6>] kthread+0xef/0xf7 [191627.738267] [<ffffffff810f3b3a>] ? time_hardirqs_on+0x15/0x28 [191627.739330] [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad [191627.741976] [<ffffffff81465592>] ret_from_fork+0x42/0x70 [191627.743080] [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad [191627.744206] ---[ end trace bbfddacb7aaada8d ]--- $ cat -n fs/btrfs/file.c 691 int __btrfs_drop_extents(struct btrfs_trans_handle *trans, (...) 758 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 759 if (key.objectid > ino || 760 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) 761 break; 762 763 fi = btrfs_item_ptr(leaf, path->slots[0], 764 struct btrfs_file_extent_item); 765 extent_type = btrfs_file_extent_type(leaf, fi); 766 767 if (extent_type == BTRFS_FILE_EXTENT_REG || 768 extent_type == BTRFS_FILE_EXTENT_PREALLOC) { (...) 774 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { (...) 778 } else { 779 WARN_ON(1); 780 extent_end = search_start; 781 } (...) This happened because the item we were processing did not match a file extent item (its key type != BTRFS_EXTENT_DATA_KEY), and even on this case we cast the item to a struct btrfs_file_extent_item pointer and then find a type field value that does not match any of the expected values (BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]). This scenario happens due to a tiny time window where a race can happen as exemplified below. For example, consider the following scenario where we're using the NO_HOLES feature and we have the following two neighbour leafs: Leaf X (has N items) Leaf Y [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ] [ (257 EXTENT_DATA 8192), ... ] slot N - 2 slot N - 1 slot 0 Our inode 257 has an implicit hole in the range [0, 8K[ (implicit rather than explicit because NO_HOLES is enabled). Now if our inode has an ordered extent for the range [4K, 8K[ that is finishing, the following can happen: CPU 1 CPU 2 btrfs_finish_ordered_io() insert_reserved_file_extent() __btrfs_drop_extents() Searches for the key (257 EXTENT_DATA 4096) through btrfs_lookup_file_extent() Key not found and we get a path where path->nodes[0] == leaf X and path->slots[0] == N Because path->slots[0] is >= btrfs_header_nritems(leaf X), we call btrfs_next_leaf() btrfs_next_leaf() releases the path inserts key (257 INODE_REF 4096) at the end of leaf X, leaf X now has N + 1 keys, and the new key is at slot N btrfs_next_leaf() searches for key (257 INODE_REF 256), with path->keep_locks set to 1, because it was the last key it saw in leaf X finds it in leaf X again and notices it's no longer the last key of the leaf, so it returns 0 with path->nodes[0] == leaf X and path->slots[0] == N (which is now < btrfs_header_nritems(leaf X)), pointing to the new key (257 INODE_REF 4096) __btrfs_drop_extents() casts the item at path->nodes[0], slot path->slots[0], to a struct btrfs_file_extent_item - it does not skip keys for the target inode with a type less than BTRFS_EXTENT_DATA_KEY (BTRFS_INODE_REF_KEY < BTRFS_EXTENT_DATA_KEY) sees a bogus value for the type field triggering the WARN_ON in the trace shown above, and sets extent_end = search_start (4096) does the if-then-else logic to fixup 0 length extent items created by a past bug from hole punching: if (extent_end == key.offset && extent_end >= search_start) goto delete_extent_item; that evaluates to true and it ends up deleting the key pointed to by path->slots[0], (257 INODE_REF 4096), from leaf X The same could happen for example for a xattr that ends up having a key with an offset value that matches search_start (very unlikely but not impossible). So fix this by ensuring that keys smaller than BTRFS_EXTENT_DATA_KEY are skipped, never casted to struct btrfs_file_extent_item and never deleted by accident. Also protect against the unexpected case of getting a key for a lower inode number by skipping that key and issuing a warning. Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-06 21:33:33 +08:00
if (key.objectid > ino)
break;
if (WARN_ON_ONCE(key.objectid < ino) ||
key.type < BTRFS_EXTENT_DATA_KEY) {
ASSERT(del_nr == 0);
path->slots[0]++;
goto next_slot;
}
if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end)
break;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(leaf, fi);
if (extent_type == BTRFS_FILE_EXTENT_REG ||
extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
extent_offset = btrfs_file_extent_offset(leaf, fi);
extent_end = key.offset +
btrfs_file_extent_num_bytes(leaf, fi);
} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
extent_end = key.offset +
btrfs_file_extent_ram_bytes(leaf, fi);
} else {
Btrfs: fix race leading to incorrect item deletion when dropping extents While running a stress test I got the following warning triggered: [191627.672810] ------------[ cut here ]------------ [191627.673949] WARNING: CPU: 8 PID: 8447 at fs/btrfs/file.c:779 __btrfs_drop_extents+0x391/0xa50 [btrfs]() (...) [191627.701485] Call Trace: [191627.702037] [<ffffffff8145f077>] dump_stack+0x4f/0x7b [191627.702992] [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2 [191627.704091] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb [191627.705380] [<ffffffffa0664499>] ? __btrfs_drop_extents+0x391/0xa50 [btrfs] [191627.706637] [<ffffffff8104b46d>] warn_slowpath_null+0x1a/0x1c [191627.707789] [<ffffffffa0664499>] __btrfs_drop_extents+0x391/0xa50 [btrfs] [191627.709155] [<ffffffff8115663c>] ? cache_alloc_debugcheck_after.isra.32+0x171/0x1d0 [191627.712444] [<ffffffff81155007>] ? kmemleak_alloc_recursive.constprop.40+0x16/0x18 [191627.714162] [<ffffffffa06570c9>] insert_reserved_file_extent.constprop.40+0x83/0x24e [btrfs] [191627.715887] [<ffffffffa065422b>] ? start_transaction+0x3bb/0x610 [btrfs] [191627.717287] [<ffffffffa065b604>] btrfs_finish_ordered_io+0x273/0x4e2 [btrfs] [191627.728865] [<ffffffffa065b888>] finish_ordered_fn+0x15/0x17 [btrfs] [191627.730045] [<ffffffffa067d688>] normal_work_helper+0x14c/0x32c [btrfs] [191627.731256] [<ffffffffa067d96a>] btrfs_endio_write_helper+0x12/0x14 [btrfs] [191627.732661] [<ffffffff81061119>] process_one_work+0x24c/0x4ae [191627.733822] [<ffffffff810615b0>] worker_thread+0x206/0x2c2 [191627.734857] [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f [191627.736052] [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f [191627.737349] [<ffffffff810669a6>] kthread+0xef/0xf7 [191627.738267] [<ffffffff810f3b3a>] ? time_hardirqs_on+0x15/0x28 [191627.739330] [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad [191627.741976] [<ffffffff81465592>] ret_from_fork+0x42/0x70 [191627.743080] [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad [191627.744206] ---[ end trace bbfddacb7aaada8d ]--- $ cat -n fs/btrfs/file.c 691 int __btrfs_drop_extents(struct btrfs_trans_handle *trans, (...) 758 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 759 if (key.objectid > ino || 760 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) 761 break; 762 763 fi = btrfs_item_ptr(leaf, path->slots[0], 764 struct btrfs_file_extent_item); 765 extent_type = btrfs_file_extent_type(leaf, fi); 766 767 if (extent_type == BTRFS_FILE_EXTENT_REG || 768 extent_type == BTRFS_FILE_EXTENT_PREALLOC) { (...) 774 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { (...) 778 } else { 779 WARN_ON(1); 780 extent_end = search_start; 781 } (...) This happened because the item we were processing did not match a file extent item (its key type != BTRFS_EXTENT_DATA_KEY), and even on this case we cast the item to a struct btrfs_file_extent_item pointer and then find a type field value that does not match any of the expected values (BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]). This scenario happens due to a tiny time window where a race can happen as exemplified below. For example, consider the following scenario where we're using the NO_HOLES feature and we have the following two neighbour leafs: Leaf X (has N items) Leaf Y [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ] [ (257 EXTENT_DATA 8192), ... ] slot N - 2 slot N - 1 slot 0 Our inode 257 has an implicit hole in the range [0, 8K[ (implicit rather than explicit because NO_HOLES is enabled). Now if our inode has an ordered extent for the range [4K, 8K[ that is finishing, the following can happen: CPU 1 CPU 2 btrfs_finish_ordered_io() insert_reserved_file_extent() __btrfs_drop_extents() Searches for the key (257 EXTENT_DATA 4096) through btrfs_lookup_file_extent() Key not found and we get a path where path->nodes[0] == leaf X and path->slots[0] == N Because path->slots[0] is >= btrfs_header_nritems(leaf X), we call btrfs_next_leaf() btrfs_next_leaf() releases the path inserts key (257 INODE_REF 4096) at the end of leaf X, leaf X now has N + 1 keys, and the new key is at slot N btrfs_next_leaf() searches for key (257 INODE_REF 256), with path->keep_locks set to 1, because it was the last key it saw in leaf X finds it in leaf X again and notices it's no longer the last key of the leaf, so it returns 0 with path->nodes[0] == leaf X and path->slots[0] == N (which is now < btrfs_header_nritems(leaf X)), pointing to the new key (257 INODE_REF 4096) __btrfs_drop_extents() casts the item at path->nodes[0], slot path->slots[0], to a struct btrfs_file_extent_item - it does not skip keys for the target inode with a type less than BTRFS_EXTENT_DATA_KEY (BTRFS_INODE_REF_KEY < BTRFS_EXTENT_DATA_KEY) sees a bogus value for the type field triggering the WARN_ON in the trace shown above, and sets extent_end = search_start (4096) does the if-then-else logic to fixup 0 length extent items created by a past bug from hole punching: if (extent_end == key.offset && extent_end >= search_start) goto delete_extent_item; that evaluates to true and it ends up deleting the key pointed to by path->slots[0], (257 INODE_REF 4096), from leaf X The same could happen for example for a xattr that ends up having a key with an offset value that matches search_start (very unlikely but not impossible). So fix this by ensuring that keys smaller than BTRFS_EXTENT_DATA_KEY are skipped, never casted to struct btrfs_file_extent_item and never deleted by accident. Also protect against the unexpected case of getting a key for a lower inode number by skipping that key and issuing a warning. Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-06 21:33:33 +08:00
/* can't happen */
BUG();
}
Btrfs: fix leaf corruption caused by ENOSPC while hole punching While running a stress test with multiple threads writing to the same btrfs file system, I ended up with a situation where a leaf was corrupted in that it had 2 file extent item keys that had the same exact key. I was able to detect this quickly thanks to the following patch which triggers an assertion as soon as a leaf is marked dirty if there are duplicated keys or out of order keys: Btrfs: check if items are ordered when a leaf is marked dirty (https://patchwork.kernel.org/patch/3955431/) Basically while running the test, I got the following in dmesg: [28877.415877] WARNING: CPU: 2 PID: 10706 at fs/btrfs/file.c:553 btrfs_drop_extent_cache+0x435/0x440 [btrfs]() (...) [28877.415917] Call Trace: [28877.415922] [<ffffffff816f1189>] dump_stack+0x4e/0x68 [28877.415926] [<ffffffff8104a32c>] warn_slowpath_common+0x8c/0xc0 [28877.415929] [<ffffffff8104a37a>] warn_slowpath_null+0x1a/0x20 [28877.415944] [<ffffffffa03775a5>] btrfs_drop_extent_cache+0x435/0x440 [btrfs] [28877.415949] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [28877.415962] [<ffffffffa03777d9>] fill_holes+0x229/0x3e0 [btrfs] [28877.415972] [<ffffffffa0345865>] ? block_rsv_add_bytes+0x55/0x80 [btrfs] [28877.415984] [<ffffffffa03792cb>] btrfs_fallocate+0xb6b/0xc20 [btrfs] (...) [29854.132560] BTRFS critical (device sdc): corrupt leaf, bad key order: block=955232256,root=1, slot=24 [29854.132565] BTRFS info (device sdc): leaf 955232256 total ptrs 40 free space 778 (...) [29854.132637] item 23 key (3486 108 667648) itemoff 2694 itemsize 53 [29854.132638] extent data disk bytenr 14574411776 nr 286720 [29854.132639] extent data offset 0 nr 286720 ram 286720 [29854.132640] item 24 key (3486 108 954368) itemoff 2641 itemsize 53 [29854.132641] extent data disk bytenr 0 nr 0 [29854.132643] extent data offset 0 nr 0 ram 0 [29854.132644] item 25 key (3486 108 954368) itemoff 2588 itemsize 53 [29854.132645] extent data disk bytenr 8699670528 nr 77824 [29854.132646] extent data offset 0 nr 77824 ram 77824 [29854.132647] item 26 key (3486 108 1146880) itemoff 2535 itemsize 53 [29854.132648] extent data disk bytenr 8699670528 nr 77824 [29854.132649] extent data offset 0 nr 77824 ram 77824 (...) [29854.132707] kernel BUG at fs/btrfs/ctree.h:3901! (...) [29854.132771] Call Trace: [29854.132779] [<ffffffffa0342b5c>] setup_items_for_insert+0x2dc/0x400 [btrfs] [29854.132791] [<ffffffffa0378537>] __btrfs_drop_extents+0xba7/0xdd0 [btrfs] [29854.132794] [<ffffffff8109c0d6>] ? trace_hardirqs_on_caller+0x16/0x1d0 [29854.132797] [<ffffffff8109c29d>] ? trace_hardirqs_on+0xd/0x10 [29854.132800] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [29854.132810] [<ffffffffa036783b>] insert_reserved_file_extent.constprop.66+0xab/0x310 [btrfs] [29854.132820] [<ffffffffa036a6c6>] __btrfs_prealloc_file_range+0x116/0x340 [btrfs] [29854.132830] [<ffffffffa0374d53>] btrfs_prealloc_file_range+0x23/0x30 [btrfs] (...) So this is caused by getting an -ENOSPC error while punching a file hole, more specifically, we get -ENOSPC error from __btrfs_drop_extents in the while loop of file.c:btrfs_punch_hole() when it's unable to modify the btree to delete one or more file extent items due to lack of enough free space. When this happens, in btrfs_punch_hole(), we attempt to reclaim free space by switching our transaction block reservation object to root->fs_info->trans_block_rsv, end our transaction and start a new transaction basically - and, we keep increasing our current offset (cur_offset) as long as it's smaller than the end of the target range (lockend) - this makes use leave the loop with cur_offset == drop_end which in turn makes us call fill_holes() for inserting a file extent item that represents a 0 bytes range hole (and this insertion succeeds, as in the meanwhile more space became available). This 0 bytes file hole extent item is a problem because any subsequent caller of __btrfs_drop_extents (regular file writes, or fallocate calls for e.g.), with a start file offset that is equal to the offset of the hole, will not remove this extent item due to the following conditional in the while loop of __btrfs_drop_extents: if (extent_end <= search_start) { path->slots[0]++; goto next_slot; } This later makes the call to setup_items_for_insert() (at the very end of __btrfs_drop_extents), insert a new file extent item with the same offset as the 0 bytes file hole extent item that follows it. Needless is to say that this causes chaos, either when reading the leaf from disk (btree_readpage_end_io_hook), where we perform leaf sanity checks or in subsequent operations that manipulate file extent items, as in the fallocate call as shown by the dmesg trace above. Without my other patch to perform the leaf sanity checks once a leaf is marked as dirty (if the integrity checker is enabled), it would have been much harder to debug this issue. This change might fix a few similar issues reported by users in the mailing list regarding assertion failures in btrfs_set_item_key_safe calls performed by __btrfs_drop_extents, such as the following report: http://comments.gmane.org/gmane.comp.file-systems.btrfs/32938 Asking fill_holes() to create a 0 bytes wide file hole item also produced the first warning in the trace above, as we passed a range to btrfs_drop_extent_cache that has an end smaller (by -1) than its start. On 3.14 kernels this issue manifests itself through leaf corruption, as we get duplicated file extent item keys in a leaf when calling setup_items_for_insert(), but on older kernels, setup_items_for_insert() isn't called by __btrfs_drop_extents(), instead we have callers of __btrfs_drop_extents(), namely the functions inode.c:insert_inline_extent() and inode.c:insert_reserved_file_extent(), calling btrfs_insert_empty_item() to insert the new file extent item, which would fail with error -EEXIST, instead of inserting a duplicated key - which is still a serious issue as it would make all similar file extent item replace operations keep failing if they target the same file range. Cc: stable@vger.kernel.org Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-04-29 20:18:40 +08:00
/*
* Don't skip extent items representing 0 byte lengths. They
* used to be created (bug) if while punching holes we hit
* -ENOSPC condition. So if we find one here, just ensure we
* delete it, otherwise we would insert a new file extent item
* with the same key (offset) as that 0 bytes length file
* extent item in the call to setup_items_for_insert() later
* in this function.
*/
if (extent_end == key.offset && extent_end >= search_start) {
last_end = extent_end;
Btrfs: fix leaf corruption caused by ENOSPC while hole punching While running a stress test with multiple threads writing to the same btrfs file system, I ended up with a situation where a leaf was corrupted in that it had 2 file extent item keys that had the same exact key. I was able to detect this quickly thanks to the following patch which triggers an assertion as soon as a leaf is marked dirty if there are duplicated keys or out of order keys: Btrfs: check if items are ordered when a leaf is marked dirty (https://patchwork.kernel.org/patch/3955431/) Basically while running the test, I got the following in dmesg: [28877.415877] WARNING: CPU: 2 PID: 10706 at fs/btrfs/file.c:553 btrfs_drop_extent_cache+0x435/0x440 [btrfs]() (...) [28877.415917] Call Trace: [28877.415922] [<ffffffff816f1189>] dump_stack+0x4e/0x68 [28877.415926] [<ffffffff8104a32c>] warn_slowpath_common+0x8c/0xc0 [28877.415929] [<ffffffff8104a37a>] warn_slowpath_null+0x1a/0x20 [28877.415944] [<ffffffffa03775a5>] btrfs_drop_extent_cache+0x435/0x440 [btrfs] [28877.415949] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [28877.415962] [<ffffffffa03777d9>] fill_holes+0x229/0x3e0 [btrfs] [28877.415972] [<ffffffffa0345865>] ? block_rsv_add_bytes+0x55/0x80 [btrfs] [28877.415984] [<ffffffffa03792cb>] btrfs_fallocate+0xb6b/0xc20 [btrfs] (...) [29854.132560] BTRFS critical (device sdc): corrupt leaf, bad key order: block=955232256,root=1, slot=24 [29854.132565] BTRFS info (device sdc): leaf 955232256 total ptrs 40 free space 778 (...) [29854.132637] item 23 key (3486 108 667648) itemoff 2694 itemsize 53 [29854.132638] extent data disk bytenr 14574411776 nr 286720 [29854.132639] extent data offset 0 nr 286720 ram 286720 [29854.132640] item 24 key (3486 108 954368) itemoff 2641 itemsize 53 [29854.132641] extent data disk bytenr 0 nr 0 [29854.132643] extent data offset 0 nr 0 ram 0 [29854.132644] item 25 key (3486 108 954368) itemoff 2588 itemsize 53 [29854.132645] extent data disk bytenr 8699670528 nr 77824 [29854.132646] extent data offset 0 nr 77824 ram 77824 [29854.132647] item 26 key (3486 108 1146880) itemoff 2535 itemsize 53 [29854.132648] extent data disk bytenr 8699670528 nr 77824 [29854.132649] extent data offset 0 nr 77824 ram 77824 (...) [29854.132707] kernel BUG at fs/btrfs/ctree.h:3901! (...) [29854.132771] Call Trace: [29854.132779] [<ffffffffa0342b5c>] setup_items_for_insert+0x2dc/0x400 [btrfs] [29854.132791] [<ffffffffa0378537>] __btrfs_drop_extents+0xba7/0xdd0 [btrfs] [29854.132794] [<ffffffff8109c0d6>] ? trace_hardirqs_on_caller+0x16/0x1d0 [29854.132797] [<ffffffff8109c29d>] ? trace_hardirqs_on+0xd/0x10 [29854.132800] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [29854.132810] [<ffffffffa036783b>] insert_reserved_file_extent.constprop.66+0xab/0x310 [btrfs] [29854.132820] [<ffffffffa036a6c6>] __btrfs_prealloc_file_range+0x116/0x340 [btrfs] [29854.132830] [<ffffffffa0374d53>] btrfs_prealloc_file_range+0x23/0x30 [btrfs] (...) So this is caused by getting an -ENOSPC error while punching a file hole, more specifically, we get -ENOSPC error from __btrfs_drop_extents in the while loop of file.c:btrfs_punch_hole() when it's unable to modify the btree to delete one or more file extent items due to lack of enough free space. When this happens, in btrfs_punch_hole(), we attempt to reclaim free space by switching our transaction block reservation object to root->fs_info->trans_block_rsv, end our transaction and start a new transaction basically - and, we keep increasing our current offset (cur_offset) as long as it's smaller than the end of the target range (lockend) - this makes use leave the loop with cur_offset == drop_end which in turn makes us call fill_holes() for inserting a file extent item that represents a 0 bytes range hole (and this insertion succeeds, as in the meanwhile more space became available). This 0 bytes file hole extent item is a problem because any subsequent caller of __btrfs_drop_extents (regular file writes, or fallocate calls for e.g.), with a start file offset that is equal to the offset of the hole, will not remove this extent item due to the following conditional in the while loop of __btrfs_drop_extents: if (extent_end <= search_start) { path->slots[0]++; goto next_slot; } This later makes the call to setup_items_for_insert() (at the very end of __btrfs_drop_extents), insert a new file extent item with the same offset as the 0 bytes file hole extent item that follows it. Needless is to say that this causes chaos, either when reading the leaf from disk (btree_readpage_end_io_hook), where we perform leaf sanity checks or in subsequent operations that manipulate file extent items, as in the fallocate call as shown by the dmesg trace above. Without my other patch to perform the leaf sanity checks once a leaf is marked as dirty (if the integrity checker is enabled), it would have been much harder to debug this issue. This change might fix a few similar issues reported by users in the mailing list regarding assertion failures in btrfs_set_item_key_safe calls performed by __btrfs_drop_extents, such as the following report: http://comments.gmane.org/gmane.comp.file-systems.btrfs/32938 Asking fill_holes() to create a 0 bytes wide file hole item also produced the first warning in the trace above, as we passed a range to btrfs_drop_extent_cache that has an end smaller (by -1) than its start. On 3.14 kernels this issue manifests itself through leaf corruption, as we get duplicated file extent item keys in a leaf when calling setup_items_for_insert(), but on older kernels, setup_items_for_insert() isn't called by __btrfs_drop_extents(), instead we have callers of __btrfs_drop_extents(), namely the functions inode.c:insert_inline_extent() and inode.c:insert_reserved_file_extent(), calling btrfs_insert_empty_item() to insert the new file extent item, which would fail with error -EEXIST, instead of inserting a duplicated key - which is still a serious issue as it would make all similar file extent item replace operations keep failing if they target the same file range. Cc: stable@vger.kernel.org Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-04-29 20:18:40 +08:00
goto delete_extent_item;
}
Btrfs: fix leaf corruption caused by ENOSPC while hole punching While running a stress test with multiple threads writing to the same btrfs file system, I ended up with a situation where a leaf was corrupted in that it had 2 file extent item keys that had the same exact key. I was able to detect this quickly thanks to the following patch which triggers an assertion as soon as a leaf is marked dirty if there are duplicated keys or out of order keys: Btrfs: check if items are ordered when a leaf is marked dirty (https://patchwork.kernel.org/patch/3955431/) Basically while running the test, I got the following in dmesg: [28877.415877] WARNING: CPU: 2 PID: 10706 at fs/btrfs/file.c:553 btrfs_drop_extent_cache+0x435/0x440 [btrfs]() (...) [28877.415917] Call Trace: [28877.415922] [<ffffffff816f1189>] dump_stack+0x4e/0x68 [28877.415926] [<ffffffff8104a32c>] warn_slowpath_common+0x8c/0xc0 [28877.415929] [<ffffffff8104a37a>] warn_slowpath_null+0x1a/0x20 [28877.415944] [<ffffffffa03775a5>] btrfs_drop_extent_cache+0x435/0x440 [btrfs] [28877.415949] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [28877.415962] [<ffffffffa03777d9>] fill_holes+0x229/0x3e0 [btrfs] [28877.415972] [<ffffffffa0345865>] ? block_rsv_add_bytes+0x55/0x80 [btrfs] [28877.415984] [<ffffffffa03792cb>] btrfs_fallocate+0xb6b/0xc20 [btrfs] (...) [29854.132560] BTRFS critical (device sdc): corrupt leaf, bad key order: block=955232256,root=1, slot=24 [29854.132565] BTRFS info (device sdc): leaf 955232256 total ptrs 40 free space 778 (...) [29854.132637] item 23 key (3486 108 667648) itemoff 2694 itemsize 53 [29854.132638] extent data disk bytenr 14574411776 nr 286720 [29854.132639] extent data offset 0 nr 286720 ram 286720 [29854.132640] item 24 key (3486 108 954368) itemoff 2641 itemsize 53 [29854.132641] extent data disk bytenr 0 nr 0 [29854.132643] extent data offset 0 nr 0 ram 0 [29854.132644] item 25 key (3486 108 954368) itemoff 2588 itemsize 53 [29854.132645] extent data disk bytenr 8699670528 nr 77824 [29854.132646] extent data offset 0 nr 77824 ram 77824 [29854.132647] item 26 key (3486 108 1146880) itemoff 2535 itemsize 53 [29854.132648] extent data disk bytenr 8699670528 nr 77824 [29854.132649] extent data offset 0 nr 77824 ram 77824 (...) [29854.132707] kernel BUG at fs/btrfs/ctree.h:3901! (...) [29854.132771] Call Trace: [29854.132779] [<ffffffffa0342b5c>] setup_items_for_insert+0x2dc/0x400 [btrfs] [29854.132791] [<ffffffffa0378537>] __btrfs_drop_extents+0xba7/0xdd0 [btrfs] [29854.132794] [<ffffffff8109c0d6>] ? trace_hardirqs_on_caller+0x16/0x1d0 [29854.132797] [<ffffffff8109c29d>] ? trace_hardirqs_on+0xd/0x10 [29854.132800] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [29854.132810] [<ffffffffa036783b>] insert_reserved_file_extent.constprop.66+0xab/0x310 [btrfs] [29854.132820] [<ffffffffa036a6c6>] __btrfs_prealloc_file_range+0x116/0x340 [btrfs] [29854.132830] [<ffffffffa0374d53>] btrfs_prealloc_file_range+0x23/0x30 [btrfs] (...) So this is caused by getting an -ENOSPC error while punching a file hole, more specifically, we get -ENOSPC error from __btrfs_drop_extents in the while loop of file.c:btrfs_punch_hole() when it's unable to modify the btree to delete one or more file extent items due to lack of enough free space. When this happens, in btrfs_punch_hole(), we attempt to reclaim free space by switching our transaction block reservation object to root->fs_info->trans_block_rsv, end our transaction and start a new transaction basically - and, we keep increasing our current offset (cur_offset) as long as it's smaller than the end of the target range (lockend) - this makes use leave the loop with cur_offset == drop_end which in turn makes us call fill_holes() for inserting a file extent item that represents a 0 bytes range hole (and this insertion succeeds, as in the meanwhile more space became available). This 0 bytes file hole extent item is a problem because any subsequent caller of __btrfs_drop_extents (regular file writes, or fallocate calls for e.g.), with a start file offset that is equal to the offset of the hole, will not remove this extent item due to the following conditional in the while loop of __btrfs_drop_extents: if (extent_end <= search_start) { path->slots[0]++; goto next_slot; } This later makes the call to setup_items_for_insert() (at the very end of __btrfs_drop_extents), insert a new file extent item with the same offset as the 0 bytes file hole extent item that follows it. Needless is to say that this causes chaos, either when reading the leaf from disk (btree_readpage_end_io_hook), where we perform leaf sanity checks or in subsequent operations that manipulate file extent items, as in the fallocate call as shown by the dmesg trace above. Without my other patch to perform the leaf sanity checks once a leaf is marked as dirty (if the integrity checker is enabled), it would have been much harder to debug this issue. This change might fix a few similar issues reported by users in the mailing list regarding assertion failures in btrfs_set_item_key_safe calls performed by __btrfs_drop_extents, such as the following report: http://comments.gmane.org/gmane.comp.file-systems.btrfs/32938 Asking fill_holes() to create a 0 bytes wide file hole item also produced the first warning in the trace above, as we passed a range to btrfs_drop_extent_cache that has an end smaller (by -1) than its start. On 3.14 kernels this issue manifests itself through leaf corruption, as we get duplicated file extent item keys in a leaf when calling setup_items_for_insert(), but on older kernels, setup_items_for_insert() isn't called by __btrfs_drop_extents(), instead we have callers of __btrfs_drop_extents(), namely the functions inode.c:insert_inline_extent() and inode.c:insert_reserved_file_extent(), calling btrfs_insert_empty_item() to insert the new file extent item, which would fail with error -EEXIST, instead of inserting a duplicated key - which is still a serious issue as it would make all similar file extent item replace operations keep failing if they target the same file range. Cc: stable@vger.kernel.org Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-04-29 20:18:40 +08:00
if (extent_end <= search_start) {
path->slots[0]++;
goto next_slot;
}
found = 1;
search_start = max(key.offset, args->start);
if (recow || !modify_tree) {
modify_tree = -1;
btrfs_release_path(path);
continue;
}
/*
* | - range to drop - |
* | -------- extent -------- |
*/
if (args->start > key.offset && args->end < extent_end) {
BUG_ON(del_nr > 0);
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -EOPNOTSUPP;
break;
}
memcpy(&new_key, &key, sizeof(new_key));
new_key.offset = args->start;
ret = btrfs_duplicate_item(trans, root, path,
&new_key);
if (ret == -EAGAIN) {
btrfs_release_path(path);
continue;
}
if (ret < 0)
break;
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi,
args->start - key.offset);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_offset += args->start - key.offset;
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - args->start);
btrfs_mark_buffer_dirty(leaf);
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
if (update_refs && disk_bytenr > 0) {
btrfs_init_generic_ref(&ref,
BTRFS_ADD_DELAYED_REF,
disk_bytenr, num_bytes, 0);
btrfs_init_data_ref(&ref,
root->root_key.objectid,
new_key.objectid,
args->start - extent_offset);
ret = btrfs_inc_extent_ref(trans, &ref);
BUG_ON(ret); /* -ENOMEM */
}
key.offset = args->start;
}
/*
* From here on out we will have actually dropped something, so
* last_end can be updated.
*/
last_end = extent_end;
/*
* | ---- range to drop ----- |
* | -------- extent -------- |
*/
if (args->start <= key.offset && args->end < extent_end) {
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -EOPNOTSUPP;
break;
}
memcpy(&new_key, &key, sizeof(new_key));
new_key.offset = args->end;
btrfs_set_item_key_safe(fs_info, path, &new_key);
extent_offset += args->end - key.offset;
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - args->end);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0)
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
args->bytes_found += args->end - key.offset;
break;
}
search_start = extent_end;
/*
* | ---- range to drop ----- |
* | -------- extent -------- |
*/
if (args->start > key.offset && args->end >= extent_end) {
BUG_ON(del_nr > 0);
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -EOPNOTSUPP;
break;
}
btrfs_set_file_extent_num_bytes(leaf, fi,
args->start - key.offset);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0)
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
args->bytes_found += extent_end - args->start;
if (args->end == extent_end)
break;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-30 02:49:59 +08:00
path->slots[0]++;
goto next_slot;
}
/*
* | ---- range to drop ----- |
* | ------ extent ------ |
*/
if (args->start <= key.offset && args->end >= extent_end) {
Btrfs: fix leaf corruption caused by ENOSPC while hole punching While running a stress test with multiple threads writing to the same btrfs file system, I ended up with a situation where a leaf was corrupted in that it had 2 file extent item keys that had the same exact key. I was able to detect this quickly thanks to the following patch which triggers an assertion as soon as a leaf is marked dirty if there are duplicated keys or out of order keys: Btrfs: check if items are ordered when a leaf is marked dirty (https://patchwork.kernel.org/patch/3955431/) Basically while running the test, I got the following in dmesg: [28877.415877] WARNING: CPU: 2 PID: 10706 at fs/btrfs/file.c:553 btrfs_drop_extent_cache+0x435/0x440 [btrfs]() (...) [28877.415917] Call Trace: [28877.415922] [<ffffffff816f1189>] dump_stack+0x4e/0x68 [28877.415926] [<ffffffff8104a32c>] warn_slowpath_common+0x8c/0xc0 [28877.415929] [<ffffffff8104a37a>] warn_slowpath_null+0x1a/0x20 [28877.415944] [<ffffffffa03775a5>] btrfs_drop_extent_cache+0x435/0x440 [btrfs] [28877.415949] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [28877.415962] [<ffffffffa03777d9>] fill_holes+0x229/0x3e0 [btrfs] [28877.415972] [<ffffffffa0345865>] ? block_rsv_add_bytes+0x55/0x80 [btrfs] [28877.415984] [<ffffffffa03792cb>] btrfs_fallocate+0xb6b/0xc20 [btrfs] (...) [29854.132560] BTRFS critical (device sdc): corrupt leaf, bad key order: block=955232256,root=1, slot=24 [29854.132565] BTRFS info (device sdc): leaf 955232256 total ptrs 40 free space 778 (...) [29854.132637] item 23 key (3486 108 667648) itemoff 2694 itemsize 53 [29854.132638] extent data disk bytenr 14574411776 nr 286720 [29854.132639] extent data offset 0 nr 286720 ram 286720 [29854.132640] item 24 key (3486 108 954368) itemoff 2641 itemsize 53 [29854.132641] extent data disk bytenr 0 nr 0 [29854.132643] extent data offset 0 nr 0 ram 0 [29854.132644] item 25 key (3486 108 954368) itemoff 2588 itemsize 53 [29854.132645] extent data disk bytenr 8699670528 nr 77824 [29854.132646] extent data offset 0 nr 77824 ram 77824 [29854.132647] item 26 key (3486 108 1146880) itemoff 2535 itemsize 53 [29854.132648] extent data disk bytenr 8699670528 nr 77824 [29854.132649] extent data offset 0 nr 77824 ram 77824 (...) [29854.132707] kernel BUG at fs/btrfs/ctree.h:3901! (...) [29854.132771] Call Trace: [29854.132779] [<ffffffffa0342b5c>] setup_items_for_insert+0x2dc/0x400 [btrfs] [29854.132791] [<ffffffffa0378537>] __btrfs_drop_extents+0xba7/0xdd0 [btrfs] [29854.132794] [<ffffffff8109c0d6>] ? trace_hardirqs_on_caller+0x16/0x1d0 [29854.132797] [<ffffffff8109c29d>] ? trace_hardirqs_on+0xd/0x10 [29854.132800] [<ffffffff8118e7be>] ? kmem_cache_alloc+0xfe/0x1c0 [29854.132810] [<ffffffffa036783b>] insert_reserved_file_extent.constprop.66+0xab/0x310 [btrfs] [29854.132820] [<ffffffffa036a6c6>] __btrfs_prealloc_file_range+0x116/0x340 [btrfs] [29854.132830] [<ffffffffa0374d53>] btrfs_prealloc_file_range+0x23/0x30 [btrfs] (...) So this is caused by getting an -ENOSPC error while punching a file hole, more specifically, we get -ENOSPC error from __btrfs_drop_extents in the while loop of file.c:btrfs_punch_hole() when it's unable to modify the btree to delete one or more file extent items due to lack of enough free space. When this happens, in btrfs_punch_hole(), we attempt to reclaim free space by switching our transaction block reservation object to root->fs_info->trans_block_rsv, end our transaction and start a new transaction basically - and, we keep increasing our current offset (cur_offset) as long as it's smaller than the end of the target range (lockend) - this makes use leave the loop with cur_offset == drop_end which in turn makes us call fill_holes() for inserting a file extent item that represents a 0 bytes range hole (and this insertion succeeds, as in the meanwhile more space became available). This 0 bytes file hole extent item is a problem because any subsequent caller of __btrfs_drop_extents (regular file writes, or fallocate calls for e.g.), with a start file offset that is equal to the offset of the hole, will not remove this extent item due to the following conditional in the while loop of __btrfs_drop_extents: if (extent_end <= search_start) { path->slots[0]++; goto next_slot; } This later makes the call to setup_items_for_insert() (at the very end of __btrfs_drop_extents), insert a new file extent item with the same offset as the 0 bytes file hole extent item that follows it. Needless is to say that this causes chaos, either when reading the leaf from disk (btree_readpage_end_io_hook), where we perform leaf sanity checks or in subsequent operations that manipulate file extent items, as in the fallocate call as shown by the dmesg trace above. Without my other patch to perform the leaf sanity checks once a leaf is marked as dirty (if the integrity checker is enabled), it would have been much harder to debug this issue. This change might fix a few similar issues reported by users in the mailing list regarding assertion failures in btrfs_set_item_key_safe calls performed by __btrfs_drop_extents, such as the following report: http://comments.gmane.org/gmane.comp.file-systems.btrfs/32938 Asking fill_holes() to create a 0 bytes wide file hole item also produced the first warning in the trace above, as we passed a range to btrfs_drop_extent_cache that has an end smaller (by -1) than its start. On 3.14 kernels this issue manifests itself through leaf corruption, as we get duplicated file extent item keys in a leaf when calling setup_items_for_insert(), but on older kernels, setup_items_for_insert() isn't called by __btrfs_drop_extents(), instead we have callers of __btrfs_drop_extents(), namely the functions inode.c:insert_inline_extent() and inode.c:insert_reserved_file_extent(), calling btrfs_insert_empty_item() to insert the new file extent item, which would fail with error -EEXIST, instead of inserting a duplicated key - which is still a serious issue as it would make all similar file extent item replace operations keep failing if they target the same file range. Cc: stable@vger.kernel.org Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-04-29 20:18:40 +08:00
delete_extent_item:
if (del_nr == 0) {
del_slot = path->slots[0];
del_nr = 1;
} else {
BUG_ON(del_slot + del_nr != path->slots[0]);
del_nr++;
}
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
if (update_refs &&
extent_type == BTRFS_FILE_EXTENT_INLINE) {
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
args->bytes_found += extent_end - key.offset;
extent_end = ALIGN(extent_end,
fs_info->sectorsize);
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
} else if (update_refs && disk_bytenr > 0) {
btrfs_init_generic_ref(&ref,
BTRFS_DROP_DELAYED_REF,
disk_bytenr, num_bytes, 0);
btrfs_init_data_ref(&ref,
root->root_key.objectid,
key.objectid,
key.offset - extent_offset);
ret = btrfs_free_extent(trans, &ref);
BUG_ON(ret); /* -ENOMEM */
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
args->bytes_found += extent_end - key.offset;
}
if (args->end == extent_end)
break;
if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
path->slots[0]++;
goto next_slot;
}
ret = btrfs_del_items(trans, root, path, del_slot,
del_nr);
if (ret) {
btrfs_abort_transaction(trans, ret);
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
break;
}
del_nr = 0;
del_slot = 0;
btrfs_release_path(path);
continue;
}
btrfs: use BUG() instead of BUG_ON(1) BUG_ON(1) leads to bogus warnings from clang when CONFIG_PROFILE_ANNOTATED_BRANCHES is set: fs/btrfs/volumes.c:5041:3: error: variable 'max_chunk_size' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] BUG_ON(1); ^~~~~~~~~ include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON' #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:48:23: note: expanded from macro 'unlikely' # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/btrfs/volumes.c:5046:9: note: uninitialized use occurs here max_chunk_size); ^~~~~~~~~~~~~~ include/linux/kernel.h:860:36: note: expanded from macro 'min' #define min(x, y) __careful_cmp(x, y, <) ^ include/linux/kernel.h:853:17: note: expanded from macro '__careful_cmp' __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op)) ^ include/linux/kernel.h:847:25: note: expanded from macro '__cmp_once' typeof(y) unique_y = (y); \ ^ fs/btrfs/volumes.c:5041:3: note: remove the 'if' if its condition is always true BUG_ON(1); ^ include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON' #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^ fs/btrfs/volumes.c:4993:20: note: initialize the variable 'max_chunk_size' to silence this warning u64 max_chunk_size; ^ = 0 Change it to BUG() so clang can see that this code path can never continue. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David Sterba <dsterba@suse.com>
2019-03-25 21:02:25 +08:00
BUG();
}
if (!ret && del_nr > 0) {
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
/*
* Set path->slots[0] to first slot, so that after the delete
* if items are move off from our leaf to its immediate left or
* right neighbor leafs, we end up with a correct and adjusted
* path->slots[0] for our insertion (if args->replace_extent).
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
*/
path->slots[0] = del_slot;
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
if (ret)
btrfs_abort_transaction(trans, ret);
}
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
leaf = path->nodes[0];
/*
* If btrfs_del_items() was called, it might have deleted a leaf, in
* which case it unlocked our path, so check path->locks[0] matches a
* write lock.
*/
if (!ret && args->replace_extent && leafs_visited == 1 &&
path->locks[0] == BTRFS_WRITE_LOCK &&
btrfs_leaf_free_space(leaf) >=
sizeof(struct btrfs_item) + args->extent_item_size) {
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = args->start;
if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
struct btrfs_key slot_key;
btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
path->slots[0]++;
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
}
setup_items_for_insert(root, path, &key,
&args->extent_item_size, 1);
args->extent_inserted = true;
}
if (!args->path)
btrfs_free_path(path);
else if (!args->extent_inserted)
Btrfs: faster file extent item replace operations When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-07 19:42:27 +08:00
btrfs_release_path(path);
out:
args->drop_end = found ? min(args->end, last_end) : args->end;
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
return ret;
}
static int extent_mergeable(struct extent_buffer *leaf, int slot,
u64 objectid, u64 bytenr, u64 orig_offset,
u64 *start, u64 *end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 extent_end;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
btrfs_file_extent_compression(leaf, fi) ||
btrfs_file_extent_encryption(leaf, fi) ||
btrfs_file_extent_other_encoding(leaf, fi))
return 0;
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
if ((*start && *start != key.offset) || (*end && *end != extent_end))
return 0;
*start = key.offset;
*end = extent_end;
return 1;
}
/*
* Mark extent in the range start - end as written.
*
* This changes extent type from 'pre-allocated' to 'regular'. If only
* part of extent is marked as written, the extent will be split into
* two or three.
*/
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode, u64 start, u64 end)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = inode->root;
struct extent_buffer *leaf;
struct btrfs_path *path;
struct btrfs_file_extent_item *fi;
struct btrfs_ref ref = { 0 };
struct btrfs_key key;
struct btrfs_key new_key;
u64 bytenr;
u64 num_bytes;
u64 extent_end;
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE) This commit introduces a new kind of back reference for btrfs metadata. Once a filesystem has been mounted with this commit, IT WILL NO LONGER BE MOUNTABLE BY OLDER KERNELS. When a tree block in subvolume tree is cow'd, the reference counts of all extents it points to are increased by one. At transaction commit time, the old root of the subvolume is recorded in a "dead root" data structure, and the btree it points to is later walked, dropping reference counts and freeing any blocks where the reference count goes to 0. The increments done during cow and decrements done after commit cancel out, and the walk is a very expensive way to go about freeing the blocks that are no longer referenced by the new btree root. This commit reduces the transaction overhead by avoiding the need for dead root records. When a non-shared tree block is cow'd, we free the old block at once, and the new block inherits old block's references. When a tree block with reference count > 1 is cow'd, we increase the reference counts of all extents the new block points to by one, and decrease the old block's reference count by one. This dead tree avoidance code removes the need to modify the reference counts of lower level extents when a non-shared tree block is cow'd. But we still need to update back ref for all pointers in the block. This is because the location of the block is recorded in the back ref item. We can solve this by introducing a new type of back ref. The new back ref provides information about pointer's key, level and in which tree the pointer lives. This information allow us to find the pointer by searching the tree. The shortcoming of the new back ref is that it only works for pointers in tree blocks referenced by their owner trees. This is mostly a problem for snapshots, where resolving one of these fuzzy back references would be O(number_of_snapshots) and quite slow. The solution used here is to use the fuzzy back references in the common case where a given tree block is only referenced by one root, and use the full back references when multiple roots have a reference on a given block. This commit adds per subvolume red-black tree to keep trace of cached inodes. The red-black tree helps the balancing code to find cached inodes whose inode numbers within a given range. This commit improves the balancing code by introducing several data structures to keep the state of balancing. The most important one is the back ref cache. It caches how the upper level tree blocks are referenced. This greatly reduce the overhead of checking back ref. The improved balancing code scales significantly better with a large number of snapshots. This is a very large commit and was written in a number of pieces. But, they depend heavily on the disk format change and were squashed together to make sure git bisect didn't end up in a bad state wrt space balancing or the format change. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 22:45:14 +08:00
u64 orig_offset;
u64 other_start;
u64 other_end;
u64 split;
int del_nr = 0;
int del_slot = 0;
int recow;
int ret = 0;
u64 ino = btrfs_ino(inode);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
again:
recow = 0;
split = start;
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = split;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0)
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != ino ||
key.type != BTRFS_EXTENT_DATA_KEY) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
if (key.offset > start || extent_end < end) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE) This commit introduces a new kind of back reference for btrfs metadata. Once a filesystem has been mounted with this commit, IT WILL NO LONGER BE MOUNTABLE BY OLDER KERNELS. When a tree block in subvolume tree is cow'd, the reference counts of all extents it points to are increased by one. At transaction commit time, the old root of the subvolume is recorded in a "dead root" data structure, and the btree it points to is later walked, dropping reference counts and freeing any blocks where the reference count goes to 0. The increments done during cow and decrements done after commit cancel out, and the walk is a very expensive way to go about freeing the blocks that are no longer referenced by the new btree root. This commit reduces the transaction overhead by avoiding the need for dead root records. When a non-shared tree block is cow'd, we free the old block at once, and the new block inherits old block's references. When a tree block with reference count > 1 is cow'd, we increase the reference counts of all extents the new block points to by one, and decrease the old block's reference count by one. This dead tree avoidance code removes the need to modify the reference counts of lower level extents when a non-shared tree block is cow'd. But we still need to update back ref for all pointers in the block. This is because the location of the block is recorded in the back ref item. We can solve this by introducing a new type of back ref. The new back ref provides information about pointer's key, level and in which tree the pointer lives. This information allow us to find the pointer by searching the tree. The shortcoming of the new back ref is that it only works for pointers in tree blocks referenced by their owner trees. This is mostly a problem for snapshots, where resolving one of these fuzzy back references would be O(number_of_snapshots) and quite slow. The solution used here is to use the fuzzy back references in the common case where a given tree block is only referenced by one root, and use the full back references when multiple roots have a reference on a given block. This commit adds per subvolume red-black tree to keep trace of cached inodes. The red-black tree helps the balancing code to find cached inodes whose inode numbers within a given range. This commit improves the balancing code by introducing several data structures to keep the state of balancing. The most important one is the back ref cache. It caches how the upper level tree blocks are referenced. This greatly reduce the overhead of checking back ref. The improved balancing code scales significantly better with a large number of snapshots. This is a very large commit and was written in a number of pieces. But, they depend heavily on the disk format change and were squashed together to make sure git bisect didn't end up in a bad state wrt space balancing or the format change. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 22:45:14 +08:00
orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
memcpy(&new_key, &key, sizeof(new_key));
if (start == key.offset && end < extent_end) {
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
new_key.offset = end;
btrfs_set_item_key_safe(fs_info, path, &new_key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - end);
btrfs_set_file_extent_offset(leaf, fi,
end - orig_offset);
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
end - other_start);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
}
if (start > key.offset && end == extent_end) {
other_start = end;
other_end = 0;
if (extent_mergeable(leaf, path->slots[0] + 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi,
start - key.offset);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
path->slots[0]++;
new_key.offset = start;
btrfs_set_item_key_safe(fs_info, path, &new_key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
other_end - start);
btrfs_set_file_extent_offset(leaf, fi,
start - orig_offset);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
}
while (start > key.offset || end < extent_end) {
if (key.offset == start)
split = end;
new_key.offset = split;
ret = btrfs_duplicate_item(trans, root, path, &new_key);
if (ret == -EAGAIN) {
btrfs_release_path(path);
goto again;
}
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
split - key.offset);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - split);
btrfs_mark_buffer_dirty(leaf);
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
num_bytes, 0);
btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
orig_offset);
ret = btrfs_inc_extent_ref(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
if (split == start) {
key.offset = start;
} else {
if (start != key.offset) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
path->slots[0]--;
extent_end = end;
}
recow = 1;
}
other_start = end;
other_end = 0;
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
num_bytes, 0);
btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset);
if (extent_mergeable(leaf, path->slots[0] + 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
extent_end = other_end;
del_slot = path->slots[0] + 1;
del_nr++;
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
key.offset = other_start;
del_slot = path->slots[0];
del_nr++;
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
if (del_nr == 0) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_mark_buffer_dirty(leaf);
} else {
fi = btrfs_item_ptr(leaf, del_slot - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - key.offset);
btrfs_mark_buffer_dirty(leaf);
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
out:
btrfs_free_path(path);
return ret;
}
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
/*
* on error we return an unlocked page and the error value
* on success we return a locked page and 0
*/
static int prepare_uptodate_page(struct inode *inode,
struct page *page, u64 pos,
bool force_uptodate)
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
{
int ret = 0;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
!PageUptodate(page)) {
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
ret = btrfs_readpage(NULL, page);
if (ret)
return ret;
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
return -EIO;
}
btrfs: subpage: fix race between prepare_pages() and btrfs_releasepage() [BUG] When running generic/095, there is a high chance to crash with subpage data RW support: assertion failed: PagePrivate(page) && page->private ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.h:3403! Internal error: Oops - BUG: 0 [#1] SMP CPU: 1 PID: 3567 Comm: fio Tainted: 5.12.0-rc7-custom+ #17 Hardware name: Khadas VIM3 (DT) Call trace: assertfail.constprop.0+0x28/0x2c [btrfs] btrfs_subpage_assert+0x80/0xa0 [btrfs] btrfs_subpage_set_uptodate+0x34/0xec [btrfs] btrfs_page_clamp_set_uptodate+0x74/0xa4 [btrfs] btrfs_dirty_pages+0x160/0x270 [btrfs] btrfs_buffered_write+0x444/0x630 [btrfs] btrfs_direct_write+0x1cc/0x2d0 [btrfs] btrfs_file_write_iter+0xc0/0x160 [btrfs] new_sync_write+0xe8/0x180 vfs_write+0x1b4/0x210 ksys_pwrite64+0x7c/0xc0 __arm64_sys_pwrite64+0x24/0x30 el0_svc_common.constprop.0+0x70/0x140 do_el0_svc+0x28/0x90 el0_svc+0x2c/0x54 el0_sync_handler+0x1a8/0x1ac el0_sync+0x170/0x180 Code: f0000160 913be042 913c4000 955444bc (d4210000) ---[ end trace 3fdd39f4cccedd68 ]--- [CAUSE] Although prepare_pages() calls find_or_create_page(), which returns the page locked, but in later prepare_uptodate_page() calls, we may call btrfs_readpage() which will unlock the page before it returns. This leaves a window where btrfs_releasepage() can sneak in and release the page, clearing page->private and causing above ASSERT(). [FIX] In prepare_uptodate_page(), we should not only check page->mapping, but also PagePrivate() to ensure we are still holding the correct page which has proper fs context setup. Reported-by: Ritesh Harjani <riteshh@linux.ibm.com> Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-26 14:35:02 +08:00
/*
* Since btrfs_readpage() will unlock the page before it
btrfs: subpage: fix a potential use-after-free in writeback helper [BUG] There is a possible use-after-free bug when running generic/095. BUG: Unable to handle kernel data access on write at 0x6b6b6b6b6b6b725b Faulting instruction address: 0xc000000000283654 c000000000283078 do_raw_spin_unlock+0x88/0x230 c0000000012b1e14 _raw_spin_unlock_irqrestore+0x44/0x90 c000000000a918dc btrfs_subpage_clear_writeback+0xac/0xe0 c0000000009e0458 end_bio_extent_writepage+0x158/0x270 c000000000b6fd14 bio_endio+0x254/0x270 c0000000009fc0f0 btrfs_end_bio+0x1a0/0x200 c000000000b6fd14 bio_endio+0x254/0x270 c000000000b781fc blk_update_request+0x46c/0x670 c000000000b8b394 blk_mq_end_request+0x34/0x1d0 c000000000d82d1c lo_complete_rq+0x11c/0x140 c000000000b880a4 blk_complete_reqs+0x84/0xb0 c0000000012b2ca4 __do_softirq+0x334/0x680 c0000000001dd878 irq_exit+0x148/0x1d0 c000000000016f4c do_IRQ+0x20c/0x240 c000000000009240 hardware_interrupt_common_virt+0x1b0/0x1c0 [CAUSE] There is very small race window like the following in generic/095. Thread 1 | Thread 2 --------------------------------+------------------------------------ end_bio_extent_writepage() | btrfs_releasepage() |- spin_lock_irqsave() | | |- end_page_writeback() | | | | |- if (PageWriteback() ||...) | | |- clear_page_extent_mapped() | | |- kfree(subpage); |- spin_unlock_irqrestore(). The race can also happen between writeback and btrfs_invalidatepage(), although that would be much harder as btrfs_invalidatepage() has much more work to do before the clear_page_extent_mapped() call. [FIX] Here we "wait" for the subapge spinlock to be released before we detach subpage structure. So this patch will introduce a new function, wait_subpage_spinlock(), to do the "wait" by acquiring the spinlock and release it. Since the caller has ensured the page is not dirty nor writeback, and page is already locked, the only way to hold the subpage spinlock is from endio function. Thus we only need to acquire the spinlock to wait for any existing holder. Reported-by: Ritesh Harjani <riteshh@linux.ibm.com> Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-26 14:35:03 +08:00
* returns, there is a window where btrfs_releasepage() can be
* called to release the page. Here we check both inode
* mapping and PagePrivate() to make sure the page was not
* released.
btrfs: subpage: fix race between prepare_pages() and btrfs_releasepage() [BUG] When running generic/095, there is a high chance to crash with subpage data RW support: assertion failed: PagePrivate(page) && page->private ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.h:3403! Internal error: Oops - BUG: 0 [#1] SMP CPU: 1 PID: 3567 Comm: fio Tainted: 5.12.0-rc7-custom+ #17 Hardware name: Khadas VIM3 (DT) Call trace: assertfail.constprop.0+0x28/0x2c [btrfs] btrfs_subpage_assert+0x80/0xa0 [btrfs] btrfs_subpage_set_uptodate+0x34/0xec [btrfs] btrfs_page_clamp_set_uptodate+0x74/0xa4 [btrfs] btrfs_dirty_pages+0x160/0x270 [btrfs] btrfs_buffered_write+0x444/0x630 [btrfs] btrfs_direct_write+0x1cc/0x2d0 [btrfs] btrfs_file_write_iter+0xc0/0x160 [btrfs] new_sync_write+0xe8/0x180 vfs_write+0x1b4/0x210 ksys_pwrite64+0x7c/0xc0 __arm64_sys_pwrite64+0x24/0x30 el0_svc_common.constprop.0+0x70/0x140 do_el0_svc+0x28/0x90 el0_svc+0x2c/0x54 el0_sync_handler+0x1a8/0x1ac el0_sync+0x170/0x180 Code: f0000160 913be042 913c4000 955444bc (d4210000) ---[ end trace 3fdd39f4cccedd68 ]--- [CAUSE] Although prepare_pages() calls find_or_create_page(), which returns the page locked, but in later prepare_uptodate_page() calls, we may call btrfs_readpage() which will unlock the page before it returns. This leaves a window where btrfs_releasepage() can sneak in and release the page, clearing page->private and causing above ASSERT(). [FIX] In prepare_uptodate_page(), we should not only check page->mapping, but also PagePrivate() to ensure we are still holding the correct page which has proper fs context setup. Reported-by: Ritesh Harjani <riteshh@linux.ibm.com> Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-26 14:35:02 +08:00
*
* The private flag check is essential for subpage as we need
* to store extra bitmap using page->private.
*/
if (page->mapping != inode->i_mapping || !PagePrivate(page)) {
unlock_page(page);
return -EAGAIN;
}
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
}
return 0;
}
/*
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
* this just gets pages into the page cache and locks them down.
*/
static noinline int prepare_pages(struct inode *inode, struct page **pages,
size_t num_pages, loff_t pos,
size_t write_bytes, bool force_uptodate)
{
int i;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
unsigned long index = pos >> PAGE_SHIFT;
gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
int err = 0;
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
int faili;
for (i = 0; i < num_pages; i++) {
again:
pages[i] = find_or_create_page(inode->i_mapping, index + i,
mask | __GFP_WRITE);
if (!pages[i]) {
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
faili = i - 1;
err = -ENOMEM;
goto fail;
}
err = set_page_extent_mapped(pages[i]);
if (err < 0) {
faili = i;
goto fail;
}
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
if (i == 0)
err = prepare_uptodate_page(inode, pages[i], pos,
force_uptodate);
if (!err && i == num_pages - 1)
err = prepare_uptodate_page(inode, pages[i],
pos + write_bytes, false);
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
if (err) {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
put_page(pages[i]);
if (err == -EAGAIN) {
err = 0;
goto again;
}
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
faili = i - 1;
goto fail;
}
wait_on_page_writeback(pages[i]);
}
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
return 0;
fail:
while (faili >= 0) {
unlock_page(pages[faili]);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
put_page(pages[faili]);
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
faili--;
}
return err;
}
/*
* This function locks the extent and properly waits for data=ordered extents
* to finish before allowing the pages to be modified if need.
*
* The return value:
* 1 - the extent is locked
* 0 - the extent is not locked, and everything is OK
* -EAGAIN - need re-prepare the pages
* the other < 0 number - Something wrong happens
*/
static noinline int
lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
size_t num_pages, loff_t pos,
size_t write_bytes,
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
u64 *lockstart, u64 *lockend,
struct extent_state **cached_state)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
u64 start_pos;
u64 last_pos;
int i;
int ret = 0;
start_pos = round_down(pos, fs_info->sectorsize);
last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
Btrfs: fix reported number of inode blocks after buffered append writes The patch from commit a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks") introduced a regression where if we do a buffered write starting at position equal to or greater than the file's size and then stat(2) the file before writeback is triggered, the number of used blocks does not change (unless there's a prealloc/unwritten extent). Example: $ xfs_io -f -c "pwrite -S 0xab 0 64K" foobar $ du -h foobar 0 foobar $ sync $ du -h foobar 64K foobar The first version of that patch didn't had this regression and the second version, which was the one committed, was made only to address some performance regression detected by the intel test robots using fs_mark. This fixes the regression by setting the new delaloc bit in the range, and doing it at btrfs_dirty_pages() while setting the regular dealloc bit as well, so that this way we set both bits at once avoiding navigation of the inode's io tree twice. Doing it at btrfs_dirty_pages() is also the most meaninful place, as we should set the new dellaloc bit when if we set the delalloc bit, which happens only if we copied bytes into the pages at __btrfs_buffered_write(). This was making some of LTP's du tests fail, which can be quickly run using a command line like the following: $ ./runltp -q -p -l /ltp.log -f commands -s du -d /mnt Fixes: a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-04 08:16:59 +08:00
if (start_pos < inode->vfs_inode.i_size) {
struct btrfs_ordered_extent *ordered;
Btrfs: fix reported number of inode blocks Currently when there are buffered writes that were not yet flushed and they fall within allocated ranges of the file (that is, not in holes or beyond eof assuming there are no prealloc extents beyond eof), btrfs simply reports an incorrect number of used blocks through the stat(2) system call (or any of its variants), regardless of mount options or inode flags (compress, compress-force, nodatacow). This is because the number of blocks used that is reported is based on the current number of bytes in the vfs inode plus the number of dealloc bytes in the btrfs inode. The later covers bytes that both fall within allocated regions of the file and holes. Example scenarios where the number of reported blocks is wrong while the buffered writes are not flushed: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt/sdc $ xfs_io -f -c "pwrite -S 0xaa 0 64K" /mnt/sdc/foo1 wrote 65536/65536 bytes at offset 0 64 KiB, 16 ops; 0.0000 sec (259.336 MiB/sec and 66390.0415 ops/sec) $ sync $ xfs_io -c "pwrite -S 0xbb 0 64K" /mnt/sdc/foo1 wrote 65536/65536 bytes at offset 0 64 KiB, 16 ops; 0.0000 sec (192.308 MiB/sec and 49230.7692 ops/sec) # The following should have reported 64K... $ du -h /mnt/sdc/foo1 128K /mnt/sdc/foo1 $ sync # After flushing the buffered write, it now reports the correct value. $ du -h /mnt/sdc/foo1 64K /mnt/sdc/foo1 $ xfs_io -f -c "falloc -k 0 128K" -c "pwrite -S 0xaa 0 64K" /mnt/sdc/foo2 wrote 65536/65536 bytes at offset 0 64 KiB, 16 ops; 0.0000 sec (520.833 MiB/sec and 133333.3333 ops/sec) $ sync $ xfs_io -c "pwrite -S 0xbb 64K 64K" /mnt/sdc/foo2 wrote 65536/65536 bytes at offset 65536 64 KiB, 16 ops; 0.0000 sec (260.417 MiB/sec and 66666.6667 ops/sec) # The following should have reported 128K... $ du -h /mnt/sdc/foo2 192K /mnt/sdc/foo2 $ sync # After flushing the buffered write, it now reports the correct value. $ du -h /mnt/sdc/foo2 128K /mnt/sdc/foo2 So the number of used file blocks is simply incorrect, unlike in other filesystems such as ext4 and xfs for example, but only while the buffered writes are not flushed. Fix this by tracking the number of delalloc bytes that fall within holes and beyond eof of a file, and use instead this new counter when reporting the number of used blocks for an inode. Another different problem that exists is that the delalloc bytes counter is reset when writeback starts (by clearing the EXTENT_DEALLOC flag from the respective range in the inode's iotree) and the vfs inode's bytes counter is only incremented when writeback finishes (through insert_reserved_file_extent()). Therefore while writeback is ongoing we simply report a wrong number of blocks used by an inode if the write operation covers a range previously unallocated. While this change does not fix this problem, it does minimizes it a lot by shortening that time window, as the new dealloc bytes counter (new_delalloc_bytes) is only decremented when writeback finishes right before updating the vfs inode's bytes counter. Fully fixing this second problem is not trivial and will be addressed later by a different patch. Signed-off-by: Filipe Manana <fdmanana@suse.com>
2017-04-03 17:45:46 +08:00
lock_extent_bits(&inode->io_tree, start_pos, last_pos,
cached_state);
ordered = btrfs_lookup_ordered_range(inode, start_pos,
last_pos - start_pos + 1);
if (ordered &&
ordered->file_offset + ordered->num_bytes > start_pos &&
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
ordered->file_offset <= last_pos) {
unlock_extent_cached(&inode->io_tree, start_pos,
last_pos, cached_state);
for (i = 0; i < num_pages; i++) {
unlock_page(pages[i]);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
put_page(pages[i]);
}
btrfs_start_ordered_extent(ordered, 1);
btrfs_put_ordered_extent(ordered);
return -EAGAIN;
}
if (ordered)
btrfs_put_ordered_extent(ordered);
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
*lockstart = start_pos;
*lockend = last_pos;
ret = 1;
}
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
/*
* We should be called after prepare_pages() which should have locked
* all pages in the range.
*/
for (i = 0; i < num_pages; i++)
WARN_ON(!PageLocked(pages[i]));
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
return ret;
}
static int check_can_nocow(struct btrfs_inode *inode, loff_t pos,
size_t *write_bytes, bool nowait)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct btrfs_root *root = inode->root;
u64 lockstart, lockend;
u64 num_bytes;
int ret;
if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
return 0;
btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IO A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be held for a long time or for ongoing IO to complete. However when calling check_can_nocow(), if the inode has prealloc extents or has the NOCOW flag set, we can block on extent (file range) locks through the call to btrfs_lock_and_flush_ordered_range(). Such lock can take a significant amount of time to be available. For example, a fiemap task may be running, and iterating through the entire file range checking all extents and doing backref walking to determine if they are shared, or a readpage operation may be in progress. Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(), after locking the file range we wait for any existing ordered extent that is in progress to complete. Another operation that can take a significant amount of time and defeat the purpose of RWF_NOWAIT. So fix this by trying to lock the file range and if it's currently locked return -EAGAIN to user space. If we are able to lock the file range without waiting and there is an ordered extent in the range, return -EAGAIN as well, instead of waiting for it to complete. Finally, don't bother trying to lock the snapshot lock of the root when attempting a RWF_NOWAIT write, as that is only important for buffered writes. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-16 01:49:39 +08:00
if (!nowait && !btrfs_drew_try_write_lock(&root->snapshot_lock))
return -EAGAIN;
lockstart = round_down(pos, fs_info->sectorsize);
lockend = round_up(pos + *write_bytes,
fs_info->sectorsize) - 1;
btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IO A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be held for a long time or for ongoing IO to complete. However when calling check_can_nocow(), if the inode has prealloc extents or has the NOCOW flag set, we can block on extent (file range) locks through the call to btrfs_lock_and_flush_ordered_range(). Such lock can take a significant amount of time to be available. For example, a fiemap task may be running, and iterating through the entire file range checking all extents and doing backref walking to determine if they are shared, or a readpage operation may be in progress. Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(), after locking the file range we wait for any existing ordered extent that is in progress to complete. Another operation that can take a significant amount of time and defeat the purpose of RWF_NOWAIT. So fix this by trying to lock the file range and if it's currently locked return -EAGAIN to user space. If we are able to lock the file range without waiting and there is an ordered extent in the range, return -EAGAIN as well, instead of waiting for it to complete. Finally, don't bother trying to lock the snapshot lock of the root when attempting a RWF_NOWAIT write, as that is only important for buffered writes. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-16 01:49:39 +08:00
num_bytes = lockend - lockstart + 1;
btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IO A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be held for a long time or for ongoing IO to complete. However when calling check_can_nocow(), if the inode has prealloc extents or has the NOCOW flag set, we can block on extent (file range) locks through the call to btrfs_lock_and_flush_ordered_range(). Such lock can take a significant amount of time to be available. For example, a fiemap task may be running, and iterating through the entire file range checking all extents and doing backref walking to determine if they are shared, or a readpage operation may be in progress. Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(), after locking the file range we wait for any existing ordered extent that is in progress to complete. Another operation that can take a significant amount of time and defeat the purpose of RWF_NOWAIT. So fix this by trying to lock the file range and if it's currently locked return -EAGAIN to user space. If we are able to lock the file range without waiting and there is an ordered extent in the range, return -EAGAIN as well, instead of waiting for it to complete. Finally, don't bother trying to lock the snapshot lock of the root when attempting a RWF_NOWAIT write, as that is only important for buffered writes. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-16 01:49:39 +08:00
if (nowait) {
struct btrfs_ordered_extent *ordered;
if (!try_lock_extent(&inode->io_tree, lockstart, lockend))
return -EAGAIN;
ordered = btrfs_lookup_ordered_range(inode, lockstart,
num_bytes);
if (ordered) {
btrfs_put_ordered_extent(ordered);
ret = -EAGAIN;
goto out_unlock;
}
} else {
btrfs_lock_and_flush_ordered_range(inode, lockstart,
lockend, NULL);
}
ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
NULL, NULL, NULL, false);
if (ret <= 0) {
ret = 0;
btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IO A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be held for a long time or for ongoing IO to complete. However when calling check_can_nocow(), if the inode has prealloc extents or has the NOCOW flag set, we can block on extent (file range) locks through the call to btrfs_lock_and_flush_ordered_range(). Such lock can take a significant amount of time to be available. For example, a fiemap task may be running, and iterating through the entire file range checking all extents and doing backref walking to determine if they are shared, or a readpage operation may be in progress. Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(), after locking the file range we wait for any existing ordered extent that is in progress to complete. Another operation that can take a significant amount of time and defeat the purpose of RWF_NOWAIT. So fix this by trying to lock the file range and if it's currently locked return -EAGAIN to user space. If we are able to lock the file range without waiting and there is an ordered extent in the range, return -EAGAIN as well, instead of waiting for it to complete. Finally, don't bother trying to lock the snapshot lock of the root when attempting a RWF_NOWAIT write, as that is only important for buffered writes. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-16 01:49:39 +08:00
if (!nowait)
btrfs_drew_write_unlock(&root->snapshot_lock);
} else {
*write_bytes = min_t(size_t, *write_bytes ,
num_bytes - pos + lockstart);
}
btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IO A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be held for a long time or for ongoing IO to complete. However when calling check_can_nocow(), if the inode has prealloc extents or has the NOCOW flag set, we can block on extent (file range) locks through the call to btrfs_lock_and_flush_ordered_range(). Such lock can take a significant amount of time to be available. For example, a fiemap task may be running, and iterating through the entire file range checking all extents and doing backref walking to determine if they are shared, or a readpage operation may be in progress. Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(), after locking the file range we wait for any existing ordered extent that is in progress to complete. Another operation that can take a significant amount of time and defeat the purpose of RWF_NOWAIT. So fix this by trying to lock the file range and if it's currently locked return -EAGAIN to user space. If we are able to lock the file range without waiting and there is an ordered extent in the range, return -EAGAIN as well, instead of waiting for it to complete. Finally, don't bother trying to lock the snapshot lock of the root when attempting a RWF_NOWAIT write, as that is only important for buffered writes. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-16 01:49:39 +08:00
out_unlock:
unlock_extent(&inode->io_tree, lockstart, lockend);
return ret;
}
static int check_nocow_nolock(struct btrfs_inode *inode, loff_t pos,
size_t *write_bytes)
{
return check_can_nocow(inode, pos, write_bytes, true);
}
/*
* Check if we can do nocow write into the range [@pos, @pos + @write_bytes)
*
* @pos: File offset
* @write_bytes: The length to write, will be updated to the nocow writeable
* range
*
* This function will flush ordered extents in the range to ensure proper
* nocow checks.
*
* Return:
* >0 and update @write_bytes if we can do nocow write
* 0 if we can't do nocow write
* -EAGAIN if we can't get the needed lock or there are ordered extents
* for * (nowait == true) case
* <0 if other error happened
*
* NOTE: Callers need to release the lock by btrfs_check_nocow_unlock().
*/
int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
size_t *write_bytes)
{
return check_can_nocow(inode, pos, write_bytes, false);
}
void btrfs_check_nocow_unlock(struct btrfs_inode *inode)
{
btrfs_drew_write_unlock(&inode->root->snapshot_lock);
}
static void update_time_for_write(struct inode *inode)
{
struct timespec64 now;
if (IS_NOCMTIME(inode))
return;
now = current_time(inode);
if (!timespec64_equal(&inode->i_mtime, &now))
inode->i_mtime = now;
if (!timespec64_equal(&inode->i_ctime, &now))
inode->i_ctime = now;
if (IS_I_VERSION(inode))
inode_inc_iversion(inode);
}
static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from,
size_t count)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
loff_t pos = iocb->ki_pos;
int ret;
loff_t oldsize;
loff_t start_pos;
if (iocb->ki_flags & IOCB_NOWAIT) {
size_t nocow_bytes = count;
/* We will allocate space in case nodatacow is not set, so bail */
if (check_nocow_nolock(BTRFS_I(inode), pos, &nocow_bytes) <= 0)
return -EAGAIN;
/*
* There are holes in the range or parts of the range that must
* be COWed (shared extents, RO block groups, etc), so just bail
* out.
*/
if (nocow_bytes < count)
return -EAGAIN;
}
current->backing_dev_info = inode_to_bdi(inode);
ret = file_remove_privs(file);
if (ret)
return ret;
/*
* We reserve space for updating the inode when we reserve space for the
* extent we are going to write, so we will enospc out there. We don't
* need to start yet another transaction to update the inode as we will
* update the inode when we finish writing whatever data we write.
*/
update_time_for_write(inode);
start_pos = round_down(pos, fs_info->sectorsize);
oldsize = i_size_read(inode);
if (start_pos > oldsize) {
/* Expand hole size to cover write data, preventing empty gap */
loff_t end_pos = round_up(pos + count, fs_info->sectorsize);
ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos);
if (ret) {
current->backing_dev_info = NULL;
return ret;
}
}
return 0;
}
static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
struct iov_iter *i)
{
struct file *file = iocb->ki_filp;
loff_t pos;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct page **pages = NULL;
struct extent_changeset *data_reserved = NULL;
u64 release_bytes = 0;
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
u64 lockstart;
u64 lockend;
size_t num_written = 0;
int nrptrs;
ssize_t ret;
bool only_release_metadata = false;
bool force_page_uptodate = false;
loff_t old_isize = i_size_read(inode);
unsigned int ilock_flags = 0;
if (iocb->ki_flags & IOCB_NOWAIT)
ilock_flags |= BTRFS_ILOCK_TRY;
ret = btrfs_inode_lock(inode, ilock_flags);
if (ret < 0)
return ret;
ret = generic_write_checks(iocb, i);
if (ret <= 0)
goto out;
ret = btrfs_write_check(iocb, i, ret);
if (ret < 0)
goto out;
pos = iocb->ki_pos;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
PAGE_SIZE / (sizeof(struct page *)));
nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
nrptrs = max(nrptrs, 8);
pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
if (!pages) {
ret = -ENOMEM;
goto out;
}
while (iov_iter_count(i) > 0) {
Btrfs: fix memory leak due to concurrent append writes with fiemap When we have a buffered write that starts at an offset greater than or equals to the file's size happening concurrently with a full ranged fiemap, we can end up leaking an extent state structure. Suppose we have a file with a size of 1Mb, and before the buffered write and fiemap are performed, it has a single extent state in its io tree representing the range from 0 to 1Mb, with the EXTENT_DELALLOC bit set. The following sequence diagram shows how the memory leak happens if a fiemap a buffered write, starting at offset 1Mb and with a length of 4Kb, are performed concurrently. CPU 1 CPU 2 extent_fiemap() --> it's a full ranged fiemap range from 0 to LLONG_MAX - 1 (9223372036854775807) --> locks range in the inode's io tree --> after this we have 2 extent states in the io tree: --> 1 for range [0, 1Mb[ with the bits EXTENT_LOCKED and EXTENT_DELALLOC_BITS set --> 1 for the range [1Mb, LLONG_MAX[ with the EXTENT_LOCKED bit set --> start buffered write at offset 1Mb with a length of 4Kb btrfs_file_write_iter() btrfs_buffered_write() --> cached_state is NULL lock_and_cleanup_extent_if_need() --> returns 0 and does not lock range because it starts at current i_size / eof --> cached_state remains NULL btrfs_dirty_pages() btrfs_set_extent_delalloc() (...) __set_extent_bit() --> splits extent state for range [1Mb, LLONG_MAX[ and now we have 2 extent states: --> one for the range [1Mb, 1Mb + 4Kb[ with EXTENT_LOCKED set --> another one for the range [1Mb + 4Kb, LLONG_MAX[ with EXTENT_LOCKED set as well --> sets EXTENT_DELALLOC on the extent state for the range [1Mb, 1Mb + 4Kb[ --> caches extent state [1Mb, 1Mb + 4Kb[ into @cached_state because it has the bit EXTENT_LOCKED set --> btrfs_buffered_write() ends up with a non-NULL cached_state and never calls anything to release its reference on it, resulting in a memory leak Fix this by calling free_extent_state() on cached_state if the range was not locked by lock_and_cleanup_extent_if_need(). The same issue can happen if anything else other than fiemap locks a range that covers eof and beyond. This could be triggered, sporadically, by test case generic/561 from the fstests suite, which makes duperemove run concurrently with fsstress, and duperemove does plenty of calls to fiemap. When CONFIG_BTRFS_DEBUG is set the leak is reported in dmesg/syslog when removing the btrfs module with a message like the following: [77100.039461] BTRFS: state leak: start 6574080 end 6582271 state 16402 in tree 0 refs 1 Otherwise (CONFIG_BTRFS_DEBUG not set) detectable with kmemleak. CC: stable@vger.kernel.org # 4.16+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-30 17:20:25 +08:00
struct extent_state *cached_state = NULL;
size_t offset = offset_in_page(pos);
size_t sector_offset;
size_t write_bytes = min(iov_iter_count(i),
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
nrptrs * (size_t)PAGE_SIZE -
offset);
size_t num_pages;
size_t reserve_bytes;
size_t dirty_pages;
size_t copied;
size_t dirty_sectors;
size_t num_sectors;
int extents_locked;
/*
* Fault pages before locking them in prepare_pages
* to avoid recursive lock
*/
if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
ret = -EFAULT;
break;
}
Btrfs: fix negative subv_writers counter and data space leak after buffered write When doing a buffered write it's possible to leave the subv_writers counter of the root, used for synchronization between buffered nocow writers and snapshotting. This happens in an exceptional case like the following: 1) We fail to allocate data space for the write, since there's not enough available data space nor enough unallocated space for allocating a new data block group; 2) Because of that failure, we try to go to NOCOW mode, which succeeds and therefore we set the local variable 'only_release_metadata' to true and set the root's sub_writers counter to 1 through the call to btrfs_start_write_no_snapshotting() made by check_can_nocow(); 3) The call to btrfs_copy_from_user() returns zero, which is very unlikely to happen but not impossible; 4) No pages are copied because btrfs_copy_from_user() returned zero; 5) We call btrfs_end_write_no_snapshotting() which decrements the root's subv_writers counter to 0; 6) We don't set 'only_release_metadata' back to 'false' because we do it only if 'copied', the value returned by btrfs_copy_from_user(), is greater than zero; 7) On the next iteration of the while loop, which processes the same page range, we are now able to allocate data space for the write (we got enough data space released in the meanwhile); 8) After this if we fail at btrfs_delalloc_reserve_metadata(), because now there isn't enough free metadata space, or in some other place further below (prepare_pages(), lock_and_cleanup_extent_if_need(), btrfs_dirty_pages()), we break out of the while loop with 'only_release_metadata' having a value of 'true'; 9) Because 'only_release_metadata' is 'true' we end up decrementing the root's subv_writers counter to -1 (through a call to btrfs_end_write_no_snapshotting()), and we also end up not releasing the data space previously reserved through btrfs_check_data_free_space(). As a consequence the mechanism for synchronizing NOCOW buffered writes with snapshotting gets broken. Fix this by always setting 'only_release_metadata' to false at the start of each iteration. Fixes: 8257b2dc3c1a ("Btrfs: introduce btrfs_{start, end}_nocow_write() for each subvolume") Fixes: 7ee9e4405f26 ("Btrfs: check if we can nocow if we don't have data space") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-11 23:41:20 +08:00
only_release_metadata = false;
sector_offset = pos & (fs_info->sectorsize - 1);
extent_changeset_release(data_reserved);
ret = btrfs_check_data_free_space(BTRFS_I(inode),
&data_reserved, pos,
write_bytes);
if (ret < 0) {
/*
* If we don't have to COW at the offset, reserve
* metadata only. write_bytes may get smaller than
* requested here.
*/
if (btrfs_check_nocow_lock(BTRFS_I(inode), pos,
&write_bytes) > 0)
only_release_metadata = true;
else
break;
}
num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE);
WARN_ON(num_pages > nrptrs);
reserve_bytes = round_up(write_bytes + sector_offset,
fs_info->sectorsize);
Btrfs: rework outstanding_extents Right now we do a lot of weird hoops around outstanding_extents in order to keep the extent count consistent. This is because we logically transfer the outstanding_extent count from the initial reservation through the set_delalloc_bits. This makes it pretty difficult to get a handle on how and when we need to mess with outstanding_extents. Fix this by revamping the rules of how we deal with outstanding_extents. Now instead everybody that is holding on to a delalloc extent is required to increase the outstanding extents count for itself. This means we'll have something like this btrfs_delalloc_reserve_metadata - outstanding_extents = 1 btrfs_set_extent_delalloc - outstanding_extents = 2 btrfs_release_delalloc_extents - outstanding_extents = 1 for an initial file write. Now take the append write where we extend an existing delalloc range but still under the maximum extent size btrfs_delalloc_reserve_metadata - outstanding_extents = 2 btrfs_set_extent_delalloc btrfs_set_bit_hook - outstanding_extents = 3 btrfs_merge_extent_hook - outstanding_extents = 2 btrfs_delalloc_release_extents - outstanding_extnets = 1 In order to make the ordered extent transition we of course must now make ordered extents carry their own outstanding_extent reservation, so for cow_file_range we end up with btrfs_add_ordered_extent - outstanding_extents = 2 clear_extent_bit - outstanding_extents = 1 btrfs_remove_ordered_extent - outstanding_extents = 0 This makes all manipulations of outstanding_extents much more explicit. Every successful call to btrfs_delalloc_reserve_metadata _must_ now be combined with btrfs_release_delalloc_extents, even in the error case, as that is the only function that actually modifies the outstanding_extents counter. The drawback to this is now we are much more likely to have transient cases where outstanding_extents is much larger than it actually should be. This could happen before as we manipulated the delalloc bits, but now it happens basically at every write. This may put more pressure on the ENOSPC flushing code, but I think making this code simpler is worth the cost. I have another change coming to mitigate this side-effect somewhat. I also added trace points for the counter manipulation. These were used by a bpf script I wrote to help track down leak issues. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-10-20 02:15:55 +08:00
WARN_ON(reserve_bytes == 0);
ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
reserve_bytes);
if (ret) {
if (!only_release_metadata)
btrfs_free_reserved_data_space(BTRFS_I(inode),
btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges [BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-27 15:10:39 +08:00
data_reserved, pos,
write_bytes);
else
btrfs_check_nocow_unlock(BTRFS_I(inode));
break;
}
release_bytes = reserve_bytes;
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
again:
/*
* This is going to setup the pages array with the number of
* pages we want, so we don't really need to worry about the
* contents of pages from loop to loop
*/
ret = prepare_pages(inode, pages, num_pages,
pos, write_bytes,
force_page_uptodate);
Btrfs: rework outstanding_extents Right now we do a lot of weird hoops around outstanding_extents in order to keep the extent count consistent. This is because we logically transfer the outstanding_extent count from the initial reservation through the set_delalloc_bits. This makes it pretty difficult to get a handle on how and when we need to mess with outstanding_extents. Fix this by revamping the rules of how we deal with outstanding_extents. Now instead everybody that is holding on to a delalloc extent is required to increase the outstanding extents count for itself. This means we'll have something like this btrfs_delalloc_reserve_metadata - outstanding_extents = 1 btrfs_set_extent_delalloc - outstanding_extents = 2 btrfs_release_delalloc_extents - outstanding_extents = 1 for an initial file write. Now take the append write where we extend an existing delalloc range but still under the maximum extent size btrfs_delalloc_reserve_metadata - outstanding_extents = 2 btrfs_set_extent_delalloc btrfs_set_bit_hook - outstanding_extents = 3 btrfs_merge_extent_hook - outstanding_extents = 2 btrfs_delalloc_release_extents - outstanding_extnets = 1 In order to make the ordered extent transition we of course must now make ordered extents carry their own outstanding_extent reservation, so for cow_file_range we end up with btrfs_add_ordered_extent - outstanding_extents = 2 clear_extent_bit - outstanding_extents = 1 btrfs_remove_ordered_extent - outstanding_extents = 0 This makes all manipulations of outstanding_extents much more explicit. Every successful call to btrfs_delalloc_reserve_metadata _must_ now be combined with btrfs_release_delalloc_extents, even in the error case, as that is the only function that actually modifies the outstanding_extents counter. The drawback to this is now we are much more likely to have transient cases where outstanding_extents is much larger than it actually should be. This could happen before as we manipulated the delalloc bits, but now it happens basically at every write. This may put more pressure on the ENOSPC flushing code, but I think making this code simpler is worth the cost. I have another change coming to mitigate this side-effect somewhat. I also added trace points for the counter manipulation. These were used by a bpf script I wrote to help track down leak issues. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-10-20 02:15:55 +08:00
if (ret) {
btrfs_delalloc_release_extents(BTRFS_I(inode),
btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents() [Background] Btrfs qgroup uses two types of reserved space for METADATA space, PERTRANS and PREALLOC. PERTRANS is metadata space reserved for each transaction started by btrfs_start_transaction(). While PREALLOC is for delalloc, where we reserve space before joining a transaction, and finally it will be converted to PERTRANS after the writeback is done. [Inconsistency] However there is inconsistency in how we handle PREALLOC metadata space. The most obvious one is: In btrfs_buffered_write(): btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true); We always free qgroup PREALLOC meta space. While in btrfs_truncate_block(): btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0)); We only free qgroup PREALLOC meta space when something went wrong. [The Correct Behavior] The correct behavior should be the one in btrfs_buffered_write(), we should always free PREALLOC metadata space. The reason is, the btrfs_delalloc_* mechanism works by: - Reserve metadata first, even it's not necessary In btrfs_delalloc_reserve_metadata() - Free the unused metadata space Normally in: btrfs_delalloc_release_extents() |- btrfs_inode_rsv_release() Here we do calculation on whether we should release or not. E.g. for 64K buffered write, the metadata rsv works like: /* The first page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=0 total: num_bytes=calc_inode_reservations() /* The first page caused one outstanding extent, thus needs metadata rsv */ /* The 2nd page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed /* The 2nd page doesn't cause new outstanding extent, needs no new meta rsv, so we free what we have reserved */ /* The 3rd~16th pages */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed (still space for one outstanding extent) This means, if btrfs_delalloc_release_extents() determines to free some space, then those space should be freed NOW. So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other than btrfs_qgroup_convert_reserved_meta(). The good news is: - The callers are not that hot The hottest caller is in btrfs_buffered_write(), which is already fixed by commit 336a8bb8e36a ("btrfs: Fix wrong btrfs_delalloc_release_extents parameter"). Thus it's not that easy to cause false EDQUOT. - The trans commit in advance for qgroup would hide the bug Since commit f5fef4593653 ("btrfs: qgroup: Make qgroup async transaction commit more aggressive"), when btrfs qgroup metadata free space is slow, it will try to commit transaction and free the wrongly converted PERTRANS space, so it's not that easy to hit such bug. [FIX] So to fix the problem, remove the @qgroup_free parameter for btrfs_delalloc_release_extents(), and always pass true to btrfs_inode_rsv_release(). Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 43b18595d660 ("btrfs: qgroup: Use separate meta reservation type for delalloc") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-14 14:34:51 +08:00
reserve_bytes);
break;
Btrfs: rework outstanding_extents Right now we do a lot of weird hoops around outstanding_extents in order to keep the extent count consistent. This is because we logically transfer the outstanding_extent count from the initial reservation through the set_delalloc_bits. This makes it pretty difficult to get a handle on how and when we need to mess with outstanding_extents. Fix this by revamping the rules of how we deal with outstanding_extents. Now instead everybody that is holding on to a delalloc extent is required to increase the outstanding extents count for itself. This means we'll have something like this btrfs_delalloc_reserve_metadata - outstanding_extents = 1 btrfs_set_extent_delalloc - outstanding_extents = 2 btrfs_release_delalloc_extents - outstanding_extents = 1 for an initial file write. Now take the append write where we extend an existing delalloc range but still under the maximum extent size btrfs_delalloc_reserve_metadata - outstanding_extents = 2 btrfs_set_extent_delalloc btrfs_set_bit_hook - outstanding_extents = 3 btrfs_merge_extent_hook - outstanding_extents = 2 btrfs_delalloc_release_extents - outstanding_extnets = 1 In order to make the ordered extent transition we of course must now make ordered extents carry their own outstanding_extent reservation, so for cow_file_range we end up with btrfs_add_ordered_extent - outstanding_extents = 2 clear_extent_bit - outstanding_extents = 1 btrfs_remove_ordered_extent - outstanding_extents = 0 This makes all manipulations of outstanding_extents much more explicit. Every successful call to btrfs_delalloc_reserve_metadata _must_ now be combined with btrfs_release_delalloc_extents, even in the error case, as that is the only function that actually modifies the outstanding_extents counter. The drawback to this is now we are much more likely to have transient cases where outstanding_extents is much larger than it actually should be. This could happen before as we manipulated the delalloc bits, but now it happens basically at every write. This may put more pressure on the ENOSPC flushing code, but I think making this code simpler is worth the cost. I have another change coming to mitigate this side-effect somewhat. I also added trace points for the counter manipulation. These were used by a bpf script I wrote to help track down leak issues. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-10-20 02:15:55 +08:00
}
extents_locked = lock_and_cleanup_extent_if_need(
BTRFS_I(inode), pages,
num_pages, pos, write_bytes, &lockstart,
&lockend, &cached_state);
if (extents_locked < 0) {
if (extents_locked == -EAGAIN)
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
goto again;
Btrfs: rework outstanding_extents Right now we do a lot of weird hoops around outstanding_extents in order to keep the extent count consistent. This is because we logically transfer the outstanding_extent count from the initial reservation through the set_delalloc_bits. This makes it pretty difficult to get a handle on how and when we need to mess with outstanding_extents. Fix this by revamping the rules of how we deal with outstanding_extents. Now instead everybody that is holding on to a delalloc extent is required to increase the outstanding extents count for itself. This means we'll have something like this btrfs_delalloc_reserve_metadata - outstanding_extents = 1 btrfs_set_extent_delalloc - outstanding_extents = 2 btrfs_release_delalloc_extents - outstanding_extents = 1 for an initial file write. Now take the append write where we extend an existing delalloc range but still under the maximum extent size btrfs_delalloc_reserve_metadata - outstanding_extents = 2 btrfs_set_extent_delalloc btrfs_set_bit_hook - outstanding_extents = 3 btrfs_merge_extent_hook - outstanding_extents = 2 btrfs_delalloc_release_extents - outstanding_extnets = 1 In order to make the ordered extent transition we of course must now make ordered extents carry their own outstanding_extent reservation, so for cow_file_range we end up with btrfs_add_ordered_extent - outstanding_extents = 2 clear_extent_bit - outstanding_extents = 1 btrfs_remove_ordered_extent - outstanding_extents = 0 This makes all manipulations of outstanding_extents much more explicit. Every successful call to btrfs_delalloc_reserve_metadata _must_ now be combined with btrfs_release_delalloc_extents, even in the error case, as that is the only function that actually modifies the outstanding_extents counter. The drawback to this is now we are much more likely to have transient cases where outstanding_extents is much larger than it actually should be. This could happen before as we manipulated the delalloc bits, but now it happens basically at every write. This may put more pressure on the ENOSPC flushing code, but I think making this code simpler is worth the cost. I have another change coming to mitigate this side-effect somewhat. I also added trace points for the counter manipulation. These were used by a bpf script I wrote to help track down leak issues. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-10-20 02:15:55 +08:00
btrfs_delalloc_release_extents(BTRFS_I(inode),
btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents() [Background] Btrfs qgroup uses two types of reserved space for METADATA space, PERTRANS and PREALLOC. PERTRANS is metadata space reserved for each transaction started by btrfs_start_transaction(). While PREALLOC is for delalloc, where we reserve space before joining a transaction, and finally it will be converted to PERTRANS after the writeback is done. [Inconsistency] However there is inconsistency in how we handle PREALLOC metadata space. The most obvious one is: In btrfs_buffered_write(): btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true); We always free qgroup PREALLOC meta space. While in btrfs_truncate_block(): btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0)); We only free qgroup PREALLOC meta space when something went wrong. [The Correct Behavior] The correct behavior should be the one in btrfs_buffered_write(), we should always free PREALLOC metadata space. The reason is, the btrfs_delalloc_* mechanism works by: - Reserve metadata first, even it's not necessary In btrfs_delalloc_reserve_metadata() - Free the unused metadata space Normally in: btrfs_delalloc_release_extents() |- btrfs_inode_rsv_release() Here we do calculation on whether we should release or not. E.g. for 64K buffered write, the metadata rsv works like: /* The first page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=0 total: num_bytes=calc_inode_reservations() /* The first page caused one outstanding extent, thus needs metadata rsv */ /* The 2nd page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed /* The 2nd page doesn't cause new outstanding extent, needs no new meta rsv, so we free what we have reserved */ /* The 3rd~16th pages */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed (still space for one outstanding extent) This means, if btrfs_delalloc_release_extents() determines to free some space, then those space should be freed NOW. So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other than btrfs_qgroup_convert_reserved_meta(). The good news is: - The callers are not that hot The hottest caller is in btrfs_buffered_write(), which is already fixed by commit 336a8bb8e36a ("btrfs: Fix wrong btrfs_delalloc_release_extents parameter"). Thus it's not that easy to cause false EDQUOT. - The trans commit in advance for qgroup would hide the bug Since commit f5fef4593653 ("btrfs: qgroup: Make qgroup async transaction commit more aggressive"), when btrfs qgroup metadata free space is slow, it will try to commit transaction and free the wrongly converted PERTRANS space, so it's not that easy to hit such bug. [FIX] So to fix the problem, remove the @qgroup_free parameter for btrfs_delalloc_release_extents(), and always pass true to btrfs_inode_rsv_release(). Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 43b18595d660 ("btrfs: qgroup: Use separate meta reservation type for delalloc") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-14 14:34:51 +08:00
reserve_bytes);
ret = extents_locked;
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
break;
}
copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
Btrfs: fix handling of faults from btrfs_copy_from_user When btrfs_copy_from_user isn't able to copy all of the pages, we need to adjust our accounting to reflect the work that was actually done. Commit 2e78c927d79 changed around the decisions a little and we ended up skipping the accounting adjustments some of the time. This commit makes sure that when we don't copy anything at all, we still hop into the adjustments, and switches to release_bytes instead of write_bytes, since write_bytes isn't aligned. The accounting errors led to warnings during btrfs_destroy_inode: [ 70.847532] WARNING: CPU: 10 PID: 514 at fs/btrfs/inode.c:9350 btrfs_destroy_inode+0x2b3/0x2c0 [ 70.847536] Modules linked in: i2c_piix4 virtio_net i2c_core input_leds button led_class serio_raw acpi_cpufreq sch_fq_codel autofs4 virtio_blk [ 70.847538] CPU: 10 PID: 514 Comm: umount Tainted: G W 4.6.0-rc6_00062_g2997da1-dirty #23 [ 70.847539] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014 [ 70.847542] 0000000000000000 ffff880ff5cafab8 ffffffff8149d5e9 0000000000000202 [ 70.847543] 0000000000000000 0000000000000000 0000000000000000 ffff880ff5cafb08 [ 70.847547] ffffffff8107bdfd ffff880ff5cafaf8 000024868120013d ffff880ff5cafb28 [ 70.847547] Call Trace: [ 70.847550] [<ffffffff8149d5e9>] dump_stack+0x51/0x78 [ 70.847551] [<ffffffff8107bdfd>] __warn+0xfd/0x120 [ 70.847553] [<ffffffff8107be3d>] warn_slowpath_null+0x1d/0x20 [ 70.847555] [<ffffffff8139c9e3>] btrfs_destroy_inode+0x2b3/0x2c0 [ 70.847556] [<ffffffff812003a1>] ? __destroy_inode+0x71/0x140 [ 70.847558] [<ffffffff812004b3>] destroy_inode+0x43/0x70 [ 70.847559] [<ffffffff810b7b5f>] ? wake_up_bit+0x2f/0x40 [ 70.847560] [<ffffffff81200c68>] evict+0x148/0x1d0 [ 70.847562] [<ffffffff81398ade>] ? start_transaction+0x3de/0x460 [ 70.847564] [<ffffffff81200d49>] dispose_list+0x59/0x80 [ 70.847565] [<ffffffff81201ba0>] evict_inodes+0x180/0x190 [ 70.847566] [<ffffffff812191ff>] ? __sync_filesystem+0x3f/0x50 [ 70.847568] [<ffffffff811e95f8>] generic_shutdown_super+0x48/0x100 [ 70.847569] [<ffffffff810b75c0>] ? woken_wake_function+0x20/0x20 [ 70.847571] [<ffffffff811e9796>] kill_anon_super+0x16/0x30 [ 70.847573] [<ffffffff81365cde>] btrfs_kill_super+0x1e/0x130 [ 70.847574] [<ffffffff811e99be>] deactivate_locked_super+0x4e/0x90 [ 70.847576] [<ffffffff811e9e61>] deactivate_super+0x51/0x70 [ 70.847577] [<ffffffff8120536f>] cleanup_mnt+0x3f/0x80 [ 70.847579] [<ffffffff81205402>] __cleanup_mnt+0x12/0x20 [ 70.847581] [<ffffffff81098358>] task_work_run+0x68/0xa0 [ 70.847582] [<ffffffff810022b6>] exit_to_usermode_loop+0xd6/0xe0 [ 70.847583] [<ffffffff81002e1d>] do_syscall_64+0xbd/0x170 [ 70.847586] [<ffffffff817d4dbc>] entry_SYSCALL64_slow_path+0x25/0x25 This is the test program I used to force short returns from btrfs_copy_from_user void *dontneed(void *arg) { char *p = arg; int ret; while(1) { ret = madvise(p, BUFSIZE/4, MADV_DONTNEED); if (ret) { perror("madvise"); exit(1); } } } int main(int ac, char **av) { int ret; int fd; char *filename; unsigned long offset; char *buf; int i; pthread_t tid; if (ac != 2) { fprintf(stderr, "usage: dammitdave filename\n"); exit(1); } buf = mmap(NULL, BUFSIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); if (buf == MAP_FAILED) { perror("mmap"); exit(1); } memset(buf, 'a', BUFSIZE); filename = av[1]; ret = pthread_create(&tid, NULL, dontneed, buf); if (ret) { fprintf(stderr, "error %d from pthread_create\n", ret); exit(1); } ret = pthread_detach(tid); if (ret) { fprintf(stderr, "pthread detach failed %d\n", ret); exit(1); } while (1) { fd = open(filename, O_RDWR | O_CREAT, 0600); if (fd < 0) { perror("open"); exit(1); } for (i = 0; i < ROUNDS; i++) { int this_write = BUFSIZE; offset = rand() % MAXSIZE; ret = pwrite(fd, buf, this_write, offset); if (ret < 0) { perror("pwrite"); exit(1); } else if (ret != this_write) { fprintf(stderr, "short write to %s offset %lu ret %d\n", filename, offset, ret); exit(1); } if (i == ROUNDS - 1) { ret = sync_file_range(fd, offset, 4096, SYNC_FILE_RANGE_WRITE); if (ret < 0) { perror("sync_file_range"); exit(1); } } } ret = ftruncate(fd, 0); if (ret < 0) { perror("ftruncate"); exit(1); } ret = close(fd); if (ret) { perror("close"); exit(1); } ret = unlink(filename); if (ret) { perror("unlink"); exit(1); } } return 0; } Signed-off-by: Chris Mason <clm@fb.com> Reported-by: Dave Jones <dsj@fb.com> Fixes: 2e78c927d79333f299a8ac81c2fd2952caeef335 cc: stable@vger.kernel.org # v4.6 Signed-off-by: Chris Mason <clm@fb.com>
2016-05-17 00:21:01 +08:00
dirty_sectors = round_up(copied + sector_offset,
fs_info->sectorsize);
dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
Btrfs: fix handling of faults from btrfs_copy_from_user When btrfs_copy_from_user isn't able to copy all of the pages, we need to adjust our accounting to reflect the work that was actually done. Commit 2e78c927d79 changed around the decisions a little and we ended up skipping the accounting adjustments some of the time. This commit makes sure that when we don't copy anything at all, we still hop into the adjustments, and switches to release_bytes instead of write_bytes, since write_bytes isn't aligned. The accounting errors led to warnings during btrfs_destroy_inode: [ 70.847532] WARNING: CPU: 10 PID: 514 at fs/btrfs/inode.c:9350 btrfs_destroy_inode+0x2b3/0x2c0 [ 70.847536] Modules linked in: i2c_piix4 virtio_net i2c_core input_leds button led_class serio_raw acpi_cpufreq sch_fq_codel autofs4 virtio_blk [ 70.847538] CPU: 10 PID: 514 Comm: umount Tainted: G W 4.6.0-rc6_00062_g2997da1-dirty #23 [ 70.847539] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014 [ 70.847542] 0000000000000000 ffff880ff5cafab8 ffffffff8149d5e9 0000000000000202 [ 70.847543] 0000000000000000 0000000000000000 0000000000000000 ffff880ff5cafb08 [ 70.847547] ffffffff8107bdfd ffff880ff5cafaf8 000024868120013d ffff880ff5cafb28 [ 70.847547] Call Trace: [ 70.847550] [<ffffffff8149d5e9>] dump_stack+0x51/0x78 [ 70.847551] [<ffffffff8107bdfd>] __warn+0xfd/0x120 [ 70.847553] [<ffffffff8107be3d>] warn_slowpath_null+0x1d/0x20 [ 70.847555] [<ffffffff8139c9e3>] btrfs_destroy_inode+0x2b3/0x2c0 [ 70.847556] [<ffffffff812003a1>] ? __destroy_inode+0x71/0x140 [ 70.847558] [<ffffffff812004b3>] destroy_inode+0x43/0x70 [ 70.847559] [<ffffffff810b7b5f>] ? wake_up_bit+0x2f/0x40 [ 70.847560] [<ffffffff81200c68>] evict+0x148/0x1d0 [ 70.847562] [<ffffffff81398ade>] ? start_transaction+0x3de/0x460 [ 70.847564] [<ffffffff81200d49>] dispose_list+0x59/0x80 [ 70.847565] [<ffffffff81201ba0>] evict_inodes+0x180/0x190 [ 70.847566] [<ffffffff812191ff>] ? __sync_filesystem+0x3f/0x50 [ 70.847568] [<ffffffff811e95f8>] generic_shutdown_super+0x48/0x100 [ 70.847569] [<ffffffff810b75c0>] ? woken_wake_function+0x20/0x20 [ 70.847571] [<ffffffff811e9796>] kill_anon_super+0x16/0x30 [ 70.847573] [<ffffffff81365cde>] btrfs_kill_super+0x1e/0x130 [ 70.847574] [<ffffffff811e99be>] deactivate_locked_super+0x4e/0x90 [ 70.847576] [<ffffffff811e9e61>] deactivate_super+0x51/0x70 [ 70.847577] [<ffffffff8120536f>] cleanup_mnt+0x3f/0x80 [ 70.847579] [<ffffffff81205402>] __cleanup_mnt+0x12/0x20 [ 70.847581] [<ffffffff81098358>] task_work_run+0x68/0xa0 [ 70.847582] [<ffffffff810022b6>] exit_to_usermode_loop+0xd6/0xe0 [ 70.847583] [<ffffffff81002e1d>] do_syscall_64+0xbd/0x170 [ 70.847586] [<ffffffff817d4dbc>] entry_SYSCALL64_slow_path+0x25/0x25 This is the test program I used to force short returns from btrfs_copy_from_user void *dontneed(void *arg) { char *p = arg; int ret; while(1) { ret = madvise(p, BUFSIZE/4, MADV_DONTNEED); if (ret) { perror("madvise"); exit(1); } } } int main(int ac, char **av) { int ret; int fd; char *filename; unsigned long offset; char *buf; int i; pthread_t tid; if (ac != 2) { fprintf(stderr, "usage: dammitdave filename\n"); exit(1); } buf = mmap(NULL, BUFSIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); if (buf == MAP_FAILED) { perror("mmap"); exit(1); } memset(buf, 'a', BUFSIZE); filename = av[1]; ret = pthread_create(&tid, NULL, dontneed, buf); if (ret) { fprintf(stderr, "error %d from pthread_create\n", ret); exit(1); } ret = pthread_detach(tid); if (ret) { fprintf(stderr, "pthread detach failed %d\n", ret); exit(1); } while (1) { fd = open(filename, O_RDWR | O_CREAT, 0600); if (fd < 0) { perror("open"); exit(1); } for (i = 0; i < ROUNDS; i++) { int this_write = BUFSIZE; offset = rand() % MAXSIZE; ret = pwrite(fd, buf, this_write, offset); if (ret < 0) { perror("pwrite"); exit(1); } else if (ret != this_write) { fprintf(stderr, "short write to %s offset %lu ret %d\n", filename, offset, ret); exit(1); } if (i == ROUNDS - 1) { ret = sync_file_range(fd, offset, 4096, SYNC_FILE_RANGE_WRITE); if (ret < 0) { perror("sync_file_range"); exit(1); } } } ret = ftruncate(fd, 0); if (ret < 0) { perror("ftruncate"); exit(1); } ret = close(fd); if (ret) { perror("close"); exit(1); } ret = unlink(filename); if (ret) { perror("unlink"); exit(1); } } return 0; } Signed-off-by: Chris Mason <clm@fb.com> Reported-by: Dave Jones <dsj@fb.com> Fixes: 2e78c927d79333f299a8ac81c2fd2952caeef335 cc: stable@vger.kernel.org # v4.6 Signed-off-by: Chris Mason <clm@fb.com>
2016-05-17 00:21:01 +08:00
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
/*
* if we have trouble faulting in the pages, fall
* back to one page at a time
*/
if (copied < write_bytes)
nrptrs = 1;
if (copied == 0) {
force_page_uptodate = true;
Btrfs: fix handling of faults from btrfs_copy_from_user When btrfs_copy_from_user isn't able to copy all of the pages, we need to adjust our accounting to reflect the work that was actually done. Commit 2e78c927d79 changed around the decisions a little and we ended up skipping the accounting adjustments some of the time. This commit makes sure that when we don't copy anything at all, we still hop into the adjustments, and switches to release_bytes instead of write_bytes, since write_bytes isn't aligned. The accounting errors led to warnings during btrfs_destroy_inode: [ 70.847532] WARNING: CPU: 10 PID: 514 at fs/btrfs/inode.c:9350 btrfs_destroy_inode+0x2b3/0x2c0 [ 70.847536] Modules linked in: i2c_piix4 virtio_net i2c_core input_leds button led_class serio_raw acpi_cpufreq sch_fq_codel autofs4 virtio_blk [ 70.847538] CPU: 10 PID: 514 Comm: umount Tainted: G W 4.6.0-rc6_00062_g2997da1-dirty #23 [ 70.847539] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014 [ 70.847542] 0000000000000000 ffff880ff5cafab8 ffffffff8149d5e9 0000000000000202 [ 70.847543] 0000000000000000 0000000000000000 0000000000000000 ffff880ff5cafb08 [ 70.847547] ffffffff8107bdfd ffff880ff5cafaf8 000024868120013d ffff880ff5cafb28 [ 70.847547] Call Trace: [ 70.847550] [<ffffffff8149d5e9>] dump_stack+0x51/0x78 [ 70.847551] [<ffffffff8107bdfd>] __warn+0xfd/0x120 [ 70.847553] [<ffffffff8107be3d>] warn_slowpath_null+0x1d/0x20 [ 70.847555] [<ffffffff8139c9e3>] btrfs_destroy_inode+0x2b3/0x2c0 [ 70.847556] [<ffffffff812003a1>] ? __destroy_inode+0x71/0x140 [ 70.847558] [<ffffffff812004b3>] destroy_inode+0x43/0x70 [ 70.847559] [<ffffffff810b7b5f>] ? wake_up_bit+0x2f/0x40 [ 70.847560] [<ffffffff81200c68>] evict+0x148/0x1d0 [ 70.847562] [<ffffffff81398ade>] ? start_transaction+0x3de/0x460 [ 70.847564] [<ffffffff81200d49>] dispose_list+0x59/0x80 [ 70.847565] [<ffffffff81201ba0>] evict_inodes+0x180/0x190 [ 70.847566] [<ffffffff812191ff>] ? __sync_filesystem+0x3f/0x50 [ 70.847568] [<ffffffff811e95f8>] generic_shutdown_super+0x48/0x100 [ 70.847569] [<ffffffff810b75c0>] ? woken_wake_function+0x20/0x20 [ 70.847571] [<ffffffff811e9796>] kill_anon_super+0x16/0x30 [ 70.847573] [<ffffffff81365cde>] btrfs_kill_super+0x1e/0x130 [ 70.847574] [<ffffffff811e99be>] deactivate_locked_super+0x4e/0x90 [ 70.847576] [<ffffffff811e9e61>] deactivate_super+0x51/0x70 [ 70.847577] [<ffffffff8120536f>] cleanup_mnt+0x3f/0x80 [ 70.847579] [<ffffffff81205402>] __cleanup_mnt+0x12/0x20 [ 70.847581] [<ffffffff81098358>] task_work_run+0x68/0xa0 [ 70.847582] [<ffffffff810022b6>] exit_to_usermode_loop+0xd6/0xe0 [ 70.847583] [<ffffffff81002e1d>] do_syscall_64+0xbd/0x170 [ 70.847586] [<ffffffff817d4dbc>] entry_SYSCALL64_slow_path+0x25/0x25 This is the test program I used to force short returns from btrfs_copy_from_user void *dontneed(void *arg) { char *p = arg; int ret; while(1) { ret = madvise(p, BUFSIZE/4, MADV_DONTNEED); if (ret) { perror("madvise"); exit(1); } } } int main(int ac, char **av) { int ret; int fd; char *filename; unsigned long offset; char *buf; int i; pthread_t tid; if (ac != 2) { fprintf(stderr, "usage: dammitdave filename\n"); exit(1); } buf = mmap(NULL, BUFSIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); if (buf == MAP_FAILED) { perror("mmap"); exit(1); } memset(buf, 'a', BUFSIZE); filename = av[1]; ret = pthread_create(&tid, NULL, dontneed, buf); if (ret) { fprintf(stderr, "error %d from pthread_create\n", ret); exit(1); } ret = pthread_detach(tid); if (ret) { fprintf(stderr, "pthread detach failed %d\n", ret); exit(1); } while (1) { fd = open(filename, O_RDWR | O_CREAT, 0600); if (fd < 0) { perror("open"); exit(1); } for (i = 0; i < ROUNDS; i++) { int this_write = BUFSIZE; offset = rand() % MAXSIZE; ret = pwrite(fd, buf, this_write, offset); if (ret < 0) { perror("pwrite"); exit(1); } else if (ret != this_write) { fprintf(stderr, "short write to %s offset %lu ret %d\n", filename, offset, ret); exit(1); } if (i == ROUNDS - 1) { ret = sync_file_range(fd, offset, 4096, SYNC_FILE_RANGE_WRITE); if (ret < 0) { perror("sync_file_range"); exit(1); } } } ret = ftruncate(fd, 0); if (ret < 0) { perror("ftruncate"); exit(1); } ret = close(fd); if (ret) { perror("close"); exit(1); } ret = unlink(filename); if (ret) { perror("unlink"); exit(1); } } return 0; } Signed-off-by: Chris Mason <clm@fb.com> Reported-by: Dave Jones <dsj@fb.com> Fixes: 2e78c927d79333f299a8ac81c2fd2952caeef335 cc: stable@vger.kernel.org # v4.6 Signed-off-by: Chris Mason <clm@fb.com>
2016-05-17 00:21:01 +08:00
dirty_sectors = 0;
Btrfs: fix regressions in copy_from_user handling Commit 914ee295af418e936ec20a08c1663eaabe4cd07a fixed deadlocks in btrfs_file_write where we would catch page faults on pages we had locked. But, there were a few problems: 1) The x86-32 iov_iter_copy_from_user_atomic code always fails to copy data when the amount to copy is more than 4K and the offset to start copying from is not page aligned. The result was btrfs_file_write looping forever retrying the iov_iter_copy_from_user_atomic We deal with this by changing btrfs_file_write to drop down to single page copies when iov_iter_copy_from_user_atomic starts returning failure. 2) The btrfs_file_write code was leaking delalloc reservations when iov_iter_copy_from_user_atomic returned zero. The looping above would result in the entire filesystem running out of delalloc reservations and constantly trying to flush things to disk. 3) btrfs_file_write will lock down page cache pages, make sure any writeback is finished, do the copy_from_user and then release them. Before the loop runs we check the first and last pages in the write to see if they are only being partially modified. If the start or end of the write isn't aligned, we make sure the corresponding pages are up to date so that we don't introduce garbage into the file. With the copy_from_user changes, we're allowing the VM to reclaim the pages after a partial update from copy_from_user, but we're not making sure the page cache page is up to date when we loop around to resume the write. We deal with this by pushing the up to date checks down into the page prep code. This fits better with how the rest of file_write works. Signed-off-by: Chris Mason <chris.mason@oracle.com> Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org> cc: stable@kernel.org
2011-02-28 22:52:08 +08:00
dirty_pages = 0;
} else {
force_page_uptodate = false;
dirty_pages = DIV_ROUND_UP(copied + offset,
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
PAGE_SIZE);
}
if (num_sectors > dirty_sectors) {
/* release everything except the sectors we dirtied */
release_bytes -= dirty_sectors << fs_info->sectorsize_bits;
if (only_release_metadata) {
btrfs_delalloc_release_metadata(BTRFS_I(inode),
btrfs: qgroup: Use separate meta reservation type for delalloc Before this patch, btrfs qgroup is mixing per-transcation meta rsv with preallocated meta rsv, making it quite easy to underflow qgroup meta reservation. Since we have the new qgroup meta rsv types, apply it to delalloc reservation. Now for delalloc, most of its reserved space will use META_PREALLOC qgroup rsv type. And for callers reducing outstanding extent like btrfs_finish_ordered_io(), they will convert corresponding META_PREALLOC reservation to META_PERTRANS. This is mainly due to the fact that current qgroup numbers will only be updated in btrfs_commit_transaction(), that's to say if we don't keep such placeholder reservation, we can exceed qgroup limitation. And for callers freeing outstanding extent in error handler, we will just free META_PREALLOC bytes. This behavior makes callers of btrfs_qgroup_release_meta() or btrfs_qgroup_convert_meta() to be aware of which type they are. So in this patch, btrfs_delalloc_release_metadata() and its callers get an extra parameter to info qgroup to do correct meta convert/release. The good news is, even we use the wrong type (convert or free), it won't cause obvious bug, as prealloc type is always in good shape, and the type only affects how per-trans meta is increased or not. So the worst case will be at most metadata limitation can be sometimes exceeded (no convert at all) or metadata limitation is reached too soon (no free at all). Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-12-12 15:34:32 +08:00
release_bytes, true);
} else {
u64 __pos;
__pos = round_down(pos,
fs_info->sectorsize) +
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
(dirty_pages << PAGE_SHIFT);
btrfs_delalloc_release_space(BTRFS_I(inode),
btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges [BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-27 15:10:39 +08:00
data_reserved, __pos,
btrfs: qgroup: Use separate meta reservation type for delalloc Before this patch, btrfs qgroup is mixing per-transcation meta rsv with preallocated meta rsv, making it quite easy to underflow qgroup meta reservation. Since we have the new qgroup meta rsv types, apply it to delalloc reservation. Now for delalloc, most of its reserved space will use META_PREALLOC qgroup rsv type. And for callers reducing outstanding extent like btrfs_finish_ordered_io(), they will convert corresponding META_PREALLOC reservation to META_PERTRANS. This is mainly due to the fact that current qgroup numbers will only be updated in btrfs_commit_transaction(), that's to say if we don't keep such placeholder reservation, we can exceed qgroup limitation. And for callers freeing outstanding extent in error handler, we will just free META_PREALLOC bytes. This behavior makes callers of btrfs_qgroup_release_meta() or btrfs_qgroup_convert_meta() to be aware of which type they are. So in this patch, btrfs_delalloc_release_metadata() and its callers get an extra parameter to info qgroup to do correct meta convert/release. The good news is, even we use the wrong type (convert or free), it won't cause obvious bug, as prealloc type is always in good shape, and the type only affects how per-trans meta is increased or not. So the worst case will be at most metadata limitation can be sometimes exceeded (no convert at all) or metadata limitation is reached too soon (no free at all). Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-12-12 15:34:32 +08:00
release_bytes, true);
}
}
release_bytes = round_up(copied + sector_offset,
fs_info->sectorsize);
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
ret = btrfs_dirty_pages(BTRFS_I(inode), pages,
dirty_pages, pos, copied,
&cached_state, only_release_metadata);
Btrfs: fix memory leak due to concurrent append writes with fiemap When we have a buffered write that starts at an offset greater than or equals to the file's size happening concurrently with a full ranged fiemap, we can end up leaking an extent state structure. Suppose we have a file with a size of 1Mb, and before the buffered write and fiemap are performed, it has a single extent state in its io tree representing the range from 0 to 1Mb, with the EXTENT_DELALLOC bit set. The following sequence diagram shows how the memory leak happens if a fiemap a buffered write, starting at offset 1Mb and with a length of 4Kb, are performed concurrently. CPU 1 CPU 2 extent_fiemap() --> it's a full ranged fiemap range from 0 to LLONG_MAX - 1 (9223372036854775807) --> locks range in the inode's io tree --> after this we have 2 extent states in the io tree: --> 1 for range [0, 1Mb[ with the bits EXTENT_LOCKED and EXTENT_DELALLOC_BITS set --> 1 for the range [1Mb, LLONG_MAX[ with the EXTENT_LOCKED bit set --> start buffered write at offset 1Mb with a length of 4Kb btrfs_file_write_iter() btrfs_buffered_write() --> cached_state is NULL lock_and_cleanup_extent_if_need() --> returns 0 and does not lock range because it starts at current i_size / eof --> cached_state remains NULL btrfs_dirty_pages() btrfs_set_extent_delalloc() (...) __set_extent_bit() --> splits extent state for range [1Mb, LLONG_MAX[ and now we have 2 extent states: --> one for the range [1Mb, 1Mb + 4Kb[ with EXTENT_LOCKED set --> another one for the range [1Mb + 4Kb, LLONG_MAX[ with EXTENT_LOCKED set as well --> sets EXTENT_DELALLOC on the extent state for the range [1Mb, 1Mb + 4Kb[ --> caches extent state [1Mb, 1Mb + 4Kb[ into @cached_state because it has the bit EXTENT_LOCKED set --> btrfs_buffered_write() ends up with a non-NULL cached_state and never calls anything to release its reference on it, resulting in a memory leak Fix this by calling free_extent_state() on cached_state if the range was not locked by lock_and_cleanup_extent_if_need(). The same issue can happen if anything else other than fiemap locks a range that covers eof and beyond. This could be triggered, sporadically, by test case generic/561 from the fstests suite, which makes duperemove run concurrently with fsstress, and duperemove does plenty of calls to fiemap. When CONFIG_BTRFS_DEBUG is set the leak is reported in dmesg/syslog when removing the btrfs module with a message like the following: [77100.039461] BTRFS: state leak: start 6574080 end 6582271 state 16402 in tree 0 refs 1 Otherwise (CONFIG_BTRFS_DEBUG not set) detectable with kmemleak. CC: stable@vger.kernel.org # 4.16+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-30 17:20:25 +08:00
/*
* If we have not locked the extent range, because the range's
* start offset is >= i_size, we might still have a non-NULL
* cached extent state, acquired while marking the extent range
* as delalloc through btrfs_dirty_pages(). Therefore free any
* possible cached extent state to avoid a memory leak.
*/
if (extents_locked)
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
unlock_extent_cached(&BTRFS_I(inode)->io_tree,
lockstart, lockend, &cached_state);
Btrfs: fix memory leak due to concurrent append writes with fiemap When we have a buffered write that starts at an offset greater than or equals to the file's size happening concurrently with a full ranged fiemap, we can end up leaking an extent state structure. Suppose we have a file with a size of 1Mb, and before the buffered write and fiemap are performed, it has a single extent state in its io tree representing the range from 0 to 1Mb, with the EXTENT_DELALLOC bit set. The following sequence diagram shows how the memory leak happens if a fiemap a buffered write, starting at offset 1Mb and with a length of 4Kb, are performed concurrently. CPU 1 CPU 2 extent_fiemap() --> it's a full ranged fiemap range from 0 to LLONG_MAX - 1 (9223372036854775807) --> locks range in the inode's io tree --> after this we have 2 extent states in the io tree: --> 1 for range [0, 1Mb[ with the bits EXTENT_LOCKED and EXTENT_DELALLOC_BITS set --> 1 for the range [1Mb, LLONG_MAX[ with the EXTENT_LOCKED bit set --> start buffered write at offset 1Mb with a length of 4Kb btrfs_file_write_iter() btrfs_buffered_write() --> cached_state is NULL lock_and_cleanup_extent_if_need() --> returns 0 and does not lock range because it starts at current i_size / eof --> cached_state remains NULL btrfs_dirty_pages() btrfs_set_extent_delalloc() (...) __set_extent_bit() --> splits extent state for range [1Mb, LLONG_MAX[ and now we have 2 extent states: --> one for the range [1Mb, 1Mb + 4Kb[ with EXTENT_LOCKED set --> another one for the range [1Mb + 4Kb, LLONG_MAX[ with EXTENT_LOCKED set as well --> sets EXTENT_DELALLOC on the extent state for the range [1Mb, 1Mb + 4Kb[ --> caches extent state [1Mb, 1Mb + 4Kb[ into @cached_state because it has the bit EXTENT_LOCKED set --> btrfs_buffered_write() ends up with a non-NULL cached_state and never calls anything to release its reference on it, resulting in a memory leak Fix this by calling free_extent_state() on cached_state if the range was not locked by lock_and_cleanup_extent_if_need(). The same issue can happen if anything else other than fiemap locks a range that covers eof and beyond. This could be triggered, sporadically, by test case generic/561 from the fstests suite, which makes duperemove run concurrently with fsstress, and duperemove does plenty of calls to fiemap. When CONFIG_BTRFS_DEBUG is set the leak is reported in dmesg/syslog when removing the btrfs module with a message like the following: [77100.039461] BTRFS: state leak: start 6574080 end 6582271 state 16402 in tree 0 refs 1 Otherwise (CONFIG_BTRFS_DEBUG not set) detectable with kmemleak. CC: stable@vger.kernel.org # 4.16+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-30 17:20:25 +08:00
else
free_extent_state(cached_state);
btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents() [Background] Btrfs qgroup uses two types of reserved space for METADATA space, PERTRANS and PREALLOC. PERTRANS is metadata space reserved for each transaction started by btrfs_start_transaction(). While PREALLOC is for delalloc, where we reserve space before joining a transaction, and finally it will be converted to PERTRANS after the writeback is done. [Inconsistency] However there is inconsistency in how we handle PREALLOC metadata space. The most obvious one is: In btrfs_buffered_write(): btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true); We always free qgroup PREALLOC meta space. While in btrfs_truncate_block(): btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0)); We only free qgroup PREALLOC meta space when something went wrong. [The Correct Behavior] The correct behavior should be the one in btrfs_buffered_write(), we should always free PREALLOC metadata space. The reason is, the btrfs_delalloc_* mechanism works by: - Reserve metadata first, even it's not necessary In btrfs_delalloc_reserve_metadata() - Free the unused metadata space Normally in: btrfs_delalloc_release_extents() |- btrfs_inode_rsv_release() Here we do calculation on whether we should release or not. E.g. for 64K buffered write, the metadata rsv works like: /* The first page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=0 total: num_bytes=calc_inode_reservations() /* The first page caused one outstanding extent, thus needs metadata rsv */ /* The 2nd page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed /* The 2nd page doesn't cause new outstanding extent, needs no new meta rsv, so we free what we have reserved */ /* The 3rd~16th pages */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed (still space for one outstanding extent) This means, if btrfs_delalloc_release_extents() determines to free some space, then those space should be freed NOW. So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other than btrfs_qgroup_convert_reserved_meta(). The good news is: - The callers are not that hot The hottest caller is in btrfs_buffered_write(), which is already fixed by commit 336a8bb8e36a ("btrfs: Fix wrong btrfs_delalloc_release_extents parameter"). Thus it's not that easy to cause false EDQUOT. - The trans commit in advance for qgroup would hide the bug Since commit f5fef4593653 ("btrfs: qgroup: Make qgroup async transaction commit more aggressive"), when btrfs qgroup metadata free space is slow, it will try to commit transaction and free the wrongly converted PERTRANS space, so it's not that easy to hit such bug. [FIX] So to fix the problem, remove the @qgroup_free parameter for btrfs_delalloc_release_extents(), and always pass true to btrfs_inode_rsv_release(). Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 43b18595d660 ("btrfs: qgroup: Use separate meta reservation type for delalloc") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-14 14:34:51 +08:00
btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
if (ret) {
btrfs_drop_pages(pages, num_pages);
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
break;
}
Btrfs: fix the reserved space leak caused by the race between nonlock dio and buffered io When we ran sysbench on the fs with compression, the following WARN_ONs were triggered: fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents); fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents); fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes); Steps to reproduce: # mkfs.btrfs -f <dev> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync prepare # cd - # umount <mnt> # mount -o compress <dev> <mnt> # cd <mnt> # sysbench --test=fileio --num-threads=8 --file-total-size=8G \ > --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \ > --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \ > --file-test-mode=sync run # cd - # umount <mnt> The reason of this problem is: Task0 Task1 btrfs_direct_IO unlock(&inode->i_mutex) lock(&inode->i_mutex) reserve_space() prepare_pages() lock_extent() clear_extent() unlock_extent() lock_extent() test_extent(uptodate) return false copy_data() set_delalloc_extent() extent need compress go back to buffered write clear_extent(DELALLOC | DIRTY) unlock_extent() Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which was set by task1, it made the dirty pages in that extents couldn't be flushed into the disk, so the reserved space for that extent was not released at the end. This patch fixes the above bug by unlocking the extent after the delalloc. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-10 19:25:04 +08:00
release_bytes = 0;
if (only_release_metadata)
btrfs_check_nocow_unlock(BTRFS_I(inode));
btrfs_drop_pages(pages, num_pages);
cond_resched();
balance_dirty_pages_ratelimited(inode->i_mapping);
pos += copied;
num_written += copied;
}
kfree(pages);
if (release_bytes) {
if (only_release_metadata) {
btrfs_check_nocow_unlock(BTRFS_I(inode));
btrfs_delalloc_release_metadata(BTRFS_I(inode),
btrfs: qgroup: Use separate meta reservation type for delalloc Before this patch, btrfs qgroup is mixing per-transcation meta rsv with preallocated meta rsv, making it quite easy to underflow qgroup meta reservation. Since we have the new qgroup meta rsv types, apply it to delalloc reservation. Now for delalloc, most of its reserved space will use META_PREALLOC qgroup rsv type. And for callers reducing outstanding extent like btrfs_finish_ordered_io(), they will convert corresponding META_PREALLOC reservation to META_PERTRANS. This is mainly due to the fact that current qgroup numbers will only be updated in btrfs_commit_transaction(), that's to say if we don't keep such placeholder reservation, we can exceed qgroup limitation. And for callers freeing outstanding extent in error handler, we will just free META_PREALLOC bytes. This behavior makes callers of btrfs_qgroup_release_meta() or btrfs_qgroup_convert_meta() to be aware of which type they are. So in this patch, btrfs_delalloc_release_metadata() and its callers get an extra parameter to info qgroup to do correct meta convert/release. The good news is, even we use the wrong type (convert or free), it won't cause obvious bug, as prealloc type is always in good shape, and the type only affects how per-trans meta is increased or not. So the worst case will be at most metadata limitation can be sometimes exceeded (no convert at all) or metadata limitation is reached too soon (no free at all). Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-12-12 15:34:32 +08:00
release_bytes, true);
} else {
btrfs_delalloc_release_space(BTRFS_I(inode),
data_reserved,
btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges [BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-27 15:10:39 +08:00
round_down(pos, fs_info->sectorsize),
btrfs: qgroup: Use separate meta reservation type for delalloc Before this patch, btrfs qgroup is mixing per-transcation meta rsv with preallocated meta rsv, making it quite easy to underflow qgroup meta reservation. Since we have the new qgroup meta rsv types, apply it to delalloc reservation. Now for delalloc, most of its reserved space will use META_PREALLOC qgroup rsv type. And for callers reducing outstanding extent like btrfs_finish_ordered_io(), they will convert corresponding META_PREALLOC reservation to META_PERTRANS. This is mainly due to the fact that current qgroup numbers will only be updated in btrfs_commit_transaction(), that's to say if we don't keep such placeholder reservation, we can exceed qgroup limitation. And for callers freeing outstanding extent in error handler, we will just free META_PREALLOC bytes. This behavior makes callers of btrfs_qgroup_release_meta() or btrfs_qgroup_convert_meta() to be aware of which type they are. So in this patch, btrfs_delalloc_release_metadata() and its callers get an extra parameter to info qgroup to do correct meta convert/release. The good news is, even we use the wrong type (convert or free), it won't cause obvious bug, as prealloc type is always in good shape, and the type only affects how per-trans meta is increased or not. So the worst case will be at most metadata limitation can be sometimes exceeded (no convert at all) or metadata limitation is reached too soon (no free at all). Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-12-12 15:34:32 +08:00
release_bytes, true);
}
}
extent_changeset_free(data_reserved);
if (num_written > 0) {
pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
iocb->ki_pos += num_written;
}
out:
btrfs_inode_unlock(inode, ilock_flags);
return num_written ? num_written : ret;
}
static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
const u32 blocksize_mask = fs_info->sectorsize - 1;
if (offset & blocksize_mask)
return -EINVAL;
if (iov_iter_alignment(iter) & blocksize_mask)
return -EINVAL;
return 0;
}
static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
loff_t pos;
ssize_t written = 0;
ssize_t written_buffered;
loff_t endbyte;
ssize_t err;
unsigned int ilock_flags = 0;
struct iomap_dio *dio = NULL;
if (iocb->ki_flags & IOCB_NOWAIT)
ilock_flags |= BTRFS_ILOCK_TRY;
/* If the write DIO is within EOF, use a shared lock */
if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode))
ilock_flags |= BTRFS_ILOCK_SHARED;
relock:
err = btrfs_inode_lock(inode, ilock_flags);
if (err < 0)
return err;
err = generic_write_checks(iocb, from);
if (err <= 0) {
btrfs_inode_unlock(inode, ilock_flags);
return err;
}
err = btrfs_write_check(iocb, from, err);
if (err < 0) {
btrfs_inode_unlock(inode, ilock_flags);
goto out;
}
pos = iocb->ki_pos;
/*
* Re-check since file size may have changed just before taking the
* lock or pos may have changed because of O_APPEND in generic_write_check()
*/
if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
pos + iov_iter_count(from) > i_size_read(inode)) {
btrfs_inode_unlock(inode, ilock_flags);
ilock_flags &= ~BTRFS_ILOCK_SHARED;
goto relock;
}
if (check_direct_IO(fs_info, from, pos)) {
btrfs_inode_unlock(inode, ilock_flags);
goto buffered;
}
dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
0);
btrfs_inode_unlock(inode, ilock_flags);
if (IS_ERR_OR_NULL(dio)) {
err = PTR_ERR_OR_ZERO(dio);
if (err < 0 && err != -ENOTBLK)
goto out;
} else {
written = iomap_dio_complete(dio);
}
if (written < 0 || !iov_iter_count(from)) {
err = written;
goto out;
}
buffered:
pos = iocb->ki_pos;
written_buffered = btrfs_buffered_write(iocb, from);
if (written_buffered < 0) {
err = written_buffered;
goto out;
}
/*
* Ensure all data is persisted. We want the next direct IO read to be
* able to read what was just written.
*/
endbyte = pos + written_buffered - 1;
err = btrfs_fdatawrite_range(inode, pos, endbyte);
if (err)
goto out;
err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
if (err)
goto out;
written += written_buffered;
iocb->ki_pos = pos + written_buffered;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 20:29:47 +08:00
invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
endbyte >> PAGE_SHIFT);
out:
return written ? written : err;
}
static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct btrfs_inode *inode = BTRFS_I(file_inode(file));
ssize_t num_written = 0;
const bool sync = iocb->ki_flags & IOCB_DSYNC;
/*
* If the fs flips readonly due to some impossible error, although we
* have opened a file as writable, we have to stop this write operation
* to ensure consistency.
*/
if (test_bit(BTRFS_FS_STATE_ERROR, &inode->root->fs_info->fs_state))
return -EROFS;
if (!(iocb->ki_flags & IOCB_DIRECT) &&
(iocb->ki_flags & IOCB_NOWAIT))
return -EOPNOTSUPP;
if (sync)
atomic_inc(&inode->sync_writers);
if (iocb->ki_flags & IOCB_DIRECT)
num_written = btrfs_direct_write(iocb, from);
else
num_written = btrfs_buffered_write(iocb, from);
btrfs: fix race between marking inode needs to be logged and log syncing We have a race between marking that an inode needs to be logged, either at btrfs_set_inode_last_trans() or at btrfs_page_mkwrite(), and between btrfs_sync_log(). The following steps describe how the race happens. 1) We are at transaction N; 2) Inode I was previously fsynced in the current transaction so it has: inode->logged_trans set to N; 3) The inode's root currently has: root->log_transid set to 1 root->last_log_commit set to 0 Which means only one log transaction was committed to far, log transaction 0. When a log tree is created we set ->log_transid and ->last_log_commit of its parent root to 0 (at btrfs_add_log_tree()); 4) One more range of pages is dirtied in inode I; 5) Some task A starts an fsync against some other inode J (same root), and so it joins log transaction 1. Before task A calls btrfs_sync_log()... 6) Task B starts an fsync against inode I, which currently has the full sync flag set, so it starts delalloc and waits for the ordered extent to complete before calling btrfs_inode_in_log() at btrfs_sync_file(); 7) During ordered extent completion we have btrfs_update_inode() called against inode I, which in turn calls btrfs_set_inode_last_trans(), which does the following: spin_lock(&inode->lock); inode->last_trans = trans->transaction->transid; inode->last_sub_trans = inode->root->log_transid; inode->last_log_commit = inode->root->last_log_commit; spin_unlock(&inode->lock); So ->last_trans is set to N and ->last_sub_trans set to 1. But before setting ->last_log_commit... 8) Task A is at btrfs_sync_log(): - it increments root->log_transid to 2 - starts writeback for all log tree extent buffers - waits for the writeback to complete - writes the super blocks - updates root->last_log_commit to 1 It's a lot of slow steps between updating root->log_transid and root->last_log_commit; 9) The task doing the ordered extent completion, currently at btrfs_set_inode_last_trans(), then finally runs: inode->last_log_commit = inode->root->last_log_commit; spin_unlock(&inode->lock); Which results in inode->last_log_commit being set to 1. The ordered extent completes; 10) Task B is resumed, and it calls btrfs_inode_in_log() which returns true because we have all the following conditions met: inode->logged_trans == N which matches fs_info->generation && inode->last_subtrans (1) <= inode->last_log_commit (1) && inode->last_subtrans (1) <= root->last_log_commit (1) && list inode->extent_tree.modified_extents is empty And as a consequence we return without logging the inode, so the existing logged version of the inode does not point to the extent that was written after the previous fsync. It should be impossible in practice for one task be able to do so much progress in btrfs_sync_log() while another task is at btrfs_set_inode_last_trans() right after it reads root->log_transid and before it reads root->last_log_commit. Even if kernel preemption is enabled we know the task at btrfs_set_inode_last_trans() can not be preempted because it is holding the inode's spinlock. However there is another place where we do the same without holding the spinlock, which is in the memory mapped write path at: vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) { (...) BTRFS_I(inode)->last_trans = fs_info->generation; BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid; BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit; (...) So with preemption happening after setting ->last_sub_trans and before setting ->last_log_commit, it is less of a stretch to have another task do enough progress at btrfs_sync_log() such that the task doing the memory mapped write ends up with ->last_sub_trans and ->last_log_commit set to the same value. It is still a big stretch to get there, as the task doing btrfs_sync_log() has to start writeback, wait for its completion and write the super blocks. So fix this in two different ways: 1) For btrfs_set_inode_last_trans(), simply set ->last_log_commit to the value of ->last_sub_trans minus 1; 2) For btrfs_page_mkwrite() only set the inode's ->last_sub_trans, just like we do for buffered and direct writes at btrfs_file_write_iter(), which is all we need to make sure multiple writes and fsyncs to an inode in the same transaction never result in an fsync missing that the inode changed and needs to be logged. Turn this into a helper function and use it both at btrfs_page_mkwrite() and at btrfs_file_write_iter() - this also fixes the problem that at btrfs_page_mkwrite() we were setting those fields without the protection of the inode's spinlock. This is an extremely unlikely race to happen in practice. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-23 20:08:48 +08:00
btrfs_set_inode_last_sub_trans(inode);
if (num_written > 0)
num_written = generic_write_sync(iocb, num_written);
if (sync)
atomic_dec(&inode->sync_writers);
current->backing_dev_info = NULL;
return num_written;
}
int btrfs_release_file(struct inode *inode, struct file *filp)
{
struct btrfs_file_private *private = filp->private_data;
if (private && private->filldir_buf)
kfree(private->filldir_buf);
kfree(private);
filp->private_data = NULL;
/*
* Set by setattr when we are about to truncate a file from a non-zero
* size to a zero size. This tries to flush down new bytes that may
* have been written if the application were using truncate to replace
* a file in place.
*/
if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE,
&BTRFS_I(inode)->runtime_flags))
filemap_flush(inode->i_mapping);
return 0;
}
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
{
int ret;
struct blk_plug plug;
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
/*
* This is only called in fsync, which would do synchronous writes, so
* a plug can merge adjacent IOs as much as possible. Esp. in case of
* multiple disks using raid profile, a large IO can be split to
* several segments of stripe length (currently 64K).
*/
blk_start_plug(&plug);
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
atomic_inc(&BTRFS_I(inode)->sync_writers);
ret = btrfs_fdatawrite_range(inode, start, end);
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
atomic_dec(&BTRFS_I(inode)->sync_writers);
blk_finish_plug(&plug);
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
return ret;
}
btrfs: fix race leading to unpersisted data and metadata on fsync When doing a fast fsync on a file, there is a race which can result in the fsync returning success to user space without logging the inode and without durably persisting new data. The following example shows one possible scenario for this: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ touch /mnt/bar $ xfs_io -f -c "pwrite -S 0xab 0 1M" -c "fsync" /mnt/baz # Now we have: # file bar == inode 257 # file baz == inode 258 $ mv /mnt/baz /mnt/foo # Now we have: # file bar == inode 257 # file foo == inode 258 $ xfs_io -c "pwrite -S 0xcd 0 1M" /mnt/foo # fsync bar before foo, it is important to trigger the race. $ xfs_io -c "fsync" /mnt/bar $ xfs_io -c "fsync" /mnt/foo # After this: # inode 257, file bar, is empty # inode 258, file foo, has 1M filled with 0xcd <power failure> # Replay the log: $ mount /dev/sdc /mnt # After this point file foo should have 1M filled with 0xcd and not 0xab The following steps explain how the race happens: 1) Before the first fsync of inode 258, when it has the "baz" name, its ->logged_trans is 0, ->last_sub_trans is 0 and ->last_log_commit is -1. The inode also has the full sync flag set; 2) After the first fsync, we set inode 258 ->logged_trans to 6, which is the generation of the current transaction, and set ->last_log_commit to 0, which is the current value of ->last_sub_trans (done at btrfs_log_inode()). The full sync flag is cleared from the inode during the fsync. The log sub transaction that was committed had an ID of 0 and when we synced the log, at btrfs_sync_log(), we incremented root->log_transid from 0 to 1; 3) During the rename: We update inode 258, through btrfs_update_inode(), and that causes its ->last_sub_trans to be set to 1 (the current log transaction ID), and ->last_log_commit remains with a value of 0. After updating inode 258, because we have previously logged the inode in the previous fsync, we log again the inode through the call to btrfs_log_new_name(). This results in updating the inode's ->last_log_commit from 0 to 1 (the current value of its ->last_sub_trans). The ->last_sub_trans of inode 257 is updated to 1, which is the ID of the next log transaction; 4) Then a buffered write against inode 258 is made. This leaves the value of ->last_sub_trans as 1 (the ID of the current log transaction, stored at root->log_transid); 5) Then an fsync against inode 257 (or any other inode other than 258), happens. This results in committing the log transaction with ID 1, which results in updating root->last_log_commit to 1 and bumping root->log_transid from 1 to 2; 6) Then an fsync against inode 258 starts. We flush delalloc and wait only for writeback to complete, since the full sync flag is not set in the inode's runtime flags - we do not wait for ordered extents to complete. Then, at btrfs_sync_file(), we call btrfs_inode_in_log() before the ordered extent completes. The call returns true: static inline bool btrfs_inode_in_log(...) { bool ret = false; spin_lock(&inode->lock); if (inode->logged_trans == generation && inode->last_sub_trans <= inode->last_log_commit && inode->last_sub_trans <= inode->root->last_log_commit) ret = true; spin_unlock(&inode->lock); return ret; } generation has a value of 6 (fs_info->generation), ->logged_trans also has a value of 6 (set when we logged the inode during the first fsync and when logging it during the rename), ->last_sub_trans has a value of 1, set during the rename (step 3), ->last_log_commit also has a value of 1 (set in step 3) and root->last_log_commit has a value of 1, which was set in step 5 when fsyncing inode 257. As a consequence we don't log the inode, any new extents and do not sync the log, resulting in a data loss if a power failure happens after the fsync and before the current transaction commits. Also, because we do not log the inode, after a power failure the mtime and ctime of the inode do not match those we had before. When the ordered extent completes before we call btrfs_inode_in_log(), then the call returns false and we log the inode and sync the log, since at the end of ordered extent completion we update the inode and set ->last_sub_trans to 2 (the value of root->log_transid) and ->last_log_commit to 1. This problem is found after removing the check for the emptiness of the inode's list of modified extents in the recent commit 209ecbb8585bf6 ("btrfs: remove stale comment and logic from btrfs_inode_in_log()"), added in the 5.13 merge window. However checking the emptiness of the list is not really the way to solve this problem, and was never intended to, because while that solves the problem for COW writes, the problem persists for NOCOW writes because in that case the list is always empty. In the case of NOCOW writes, even though we wait for the writeback to complete before returning from btrfs_sync_file(), we end up not logging the inode, which has a new mtime/ctime, and because we don't sync the log, we never issue disk barriers (send REQ_PREFLUSH to the device) since that only happens when we sync the log (when we write super blocks at btrfs_sync_log()). So effectively, for a NOCOW case, when we return from btrfs_sync_file() to user space, we are not guaranteeing that the data is durably persisted on disk. Also, while the example above uses a rename exchange to show how the problem happens, it is not the only way to trigger it. An alternative could be adding a new hard link to inode 258, since that also results in calling btrfs_log_new_name() and updating the inode in the log. An example reproducer using the addition of a hard link instead of a rename operation: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ touch /mnt/bar $ xfs_io -f -c "pwrite -S 0xab 0 1M" -c "fsync" /mnt/foo $ ln /mnt/foo /mnt/foo_link $ xfs_io -c "pwrite -S 0xcd 0 1M" /mnt/foo $ xfs_io -c "fsync" /mnt/bar $ xfs_io -c "fsync" /mnt/foo <power failure> # Replay the log: $ mount /dev/sdc /mnt # After this point file foo often has 1M filled with 0xab and not 0xcd The reasons leading to the final fsync of file foo, inode 258, not persisting the new data are the same as for the previous example with a rename operation. So fix by never skipping logging and log syncing when there are still any ordered extents in flight. To avoid making the conditional if statement that checks if logging an inode is needed harder to read, place all the logic into an helper function with separate if statements to make it more manageable and easier to read. A test case for fstests will follow soon. For NOCOW writes, the problem existed before commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), introduced in kernel 4.19, then it went away with that commit since we started to always wait for ordered extent completion before logging. The problem came back again once the fast fsync path was changed again to avoid waiting for ordered extent completion, in commit 487781796d3022 ("btrfs: make fast fsyncs wait only for writeback"), added in kernel 5.10. However, for COW writes, the race only happens after the recent commit 209ecbb8585bf6 ("btrfs: remove stale comment and logic from btrfs_inode_in_log()"), introduced in the 5.13 merge window. For NOCOW writes, the bug existed before that commit. So tag 5.10+ as the release for stable backports. CC: stable@vger.kernel.org # 5.10+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-04-27 18:27:20 +08:00
static inline bool skip_inode_logging(const struct btrfs_log_ctx *ctx)
{
struct btrfs_inode *inode = BTRFS_I(ctx->inode);
struct btrfs_fs_info *fs_info = inode->root->fs_info;
if (btrfs_inode_in_log(inode, fs_info->generation) &&
list_empty(&ctx->ordered_extents))
return true;
/*
* If we are doing a fast fsync we can not bail out if the inode's
* last_trans is <= then the last committed transaction, because we only
* update the last_trans of the inode during ordered extent completion,
* and for a fast fsync we don't wait for that, we only wait for the
* writeback to complete.
*/
if (inode->last_trans <= fs_info->last_trans_committed &&
(test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) ||
list_empty(&ctx->ordered_extents)))
return true;
return false;
}
/*
* fsync call for both files and directories. This logs the inode into
* the tree log instead of forcing full commits whenever possible.
*
* It needs to call filemap_fdatawait so that all ordered extent updates are
* in the metadata btree are up to date for copying to the log.
*
* It drops the inode mutex before doing the tree log commit. This is an
* important optimization for directories because holding the mutex prevents
* new operations on the dir while we write to disk.
*/
int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
{
btrfs: fix crash/invalid memory access on fsync when using overlayfs If the lower or upper directory of an overlayfs mount belong to a btrfs file system and we fsync the file through the overlayfs' merged directory we ended up accessing an inode that didn't belong to btrfs as if it were a btrfs inode at btrfs_sync_file() resulting in a crash like the following: [ 7782.588845] BUG: unable to handle kernel NULL pointer dereference at 0000000000000544 [ 7782.590624] IP: [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs] [ 7782.591931] PGD 4d954067 PUD 1e878067 PMD 0 [ 7782.592016] Oops: 0002 [#6] PREEMPT SMP DEBUG_PAGEALLOC [ 7782.592016] Modules linked in: btrfs overlay ppdev crc32c_generic evdev xor raid6_pq psmouse pcspkr sg serio_raw acpi_cpufreq parport_pc parport tpm_tis i2c_piix4 tpm i2c_core processor button loop autofs4 ext4 crc16 mbcache jbd2 sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio scsi_mod e1000 floppy [last unloaded: btrfs] [ 7782.592016] CPU: 10 PID: 16437 Comm: xfs_io Tainted: G D 4.5.0-rc6-btrfs-next-26+ #1 [ 7782.592016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [ 7782.592016] task: ffff88001b8d40c0 ti: ffff880137488000 task.ti: ffff880137488000 [ 7782.592016] RIP: 0010:[<ffffffffa030b7ab>] [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs] [ 7782.592016] RSP: 0018:ffff88013748be40 EFLAGS: 00010286 [ 7782.592016] RAX: 0000000080000000 RBX: ffff880133b30c88 RCX: 0000000000000001 [ 7782.592016] RDX: 0000000000000001 RSI: ffffffff8148fec0 RDI: 00000000ffffffff [ 7782.592016] RBP: ffff88013748bec0 R08: 0000000000000001 R09: 0000000000000000 [ 7782.624248] R10: ffff88013748be40 R11: 0000000000000246 R12: 0000000000000000 [ 7782.624248] R13: 0000000000000000 R14: 00000000009305a0 R15: ffff880015e3be40 [ 7782.624248] FS: 00007fa83b9cb700(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000 [ 7782.624248] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7782.624248] CR2: 0000000000000544 CR3: 00000001fa652000 CR4: 00000000000006e0 [ 7782.624248] Stack: [ 7782.624248] ffffffff8108b5cc ffff88013748bec0 0000000000000246 ffff8800b005ded0 [ 7782.624248] ffff880133b30d60 8000000000000000 7fffffffffffffff 0000000000000246 [ 7782.624248] 0000000000000246 ffffffff81074f9b ffffffff8104357c ffff880015e3be40 [ 7782.624248] Call Trace: [ 7782.624248] [<ffffffff8108b5cc>] ? arch_local_irq_save+0x9/0xc [ 7782.624248] [<ffffffff81074f9b>] ? ___might_sleep+0xce/0x217 [ 7782.624248] [<ffffffff8104357c>] ? __do_page_fault+0x3c0/0x43a [ 7782.624248] [<ffffffff811a2351>] vfs_fsync_range+0x8c/0x9e [ 7782.624248] [<ffffffff811a237f>] vfs_fsync+0x1c/0x1e [ 7782.624248] [<ffffffff811a24d6>] do_fsync+0x31/0x4a [ 7782.624248] [<ffffffff811a2700>] SyS_fsync+0x10/0x14 [ 7782.624248] [<ffffffff81493617>] entry_SYSCALL_64_fastpath+0x12/0x6b [ 7782.624248] Code: 85 c0 0f 85 e2 02 00 00 48 8b 45 b0 31 f6 4c 29 e8 48 ff c0 48 89 45 a8 48 8d 83 d8 00 00 00 48 89 c7 48 89 45 a0 e8 fc 43 18 e1 <f0> 41 ff 84 24 44 05 00 00 48 8b 83 58 ff ff ff 48 c1 e8 07 83 [ 7782.624248] RIP [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs] [ 7782.624248] RSP <ffff88013748be40> [ 7782.624248] CR2: 0000000000000544 [ 7782.661994] ---[ end trace 721e14960eb939bc ]--- This started happening since commit 4bacc9c9234 (overlayfs: Make f_path always point to the overlay and f_inode to the underlay) and even though after this change we could still access the btrfs inode through struct file->f_mapping->host or struct file->f_inode, we would end up resulting in more similar issues later on at check_parent_dirs_for_sync() because the dentry we got (from struct file->f_path.dentry) was from overlayfs and not from btrfs, that is, we had no way of getting the dentry that belonged to btrfs (we always got the dentry that belonged to overlayfs). The new patch from Miklos Szeredi, titled "vfs: add file_dentry()" and recently submitted to linux-fsdevel, adds a file_dentry() API that allows us to get the btrfs dentry from the input file and therefore being able to fsync when the upper and lower directories belong to btrfs filesystems. This issue has been reported several times by users in the mailing list and bugzilla. A test case for xfstests is being submitted as well. Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=101951 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109791 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Cc: stable@vger.kernel.org
2016-03-31 07:03:13 +08:00
struct dentry *dentry = file_dentry(file);
struct inode *inode = d_inode(dentry);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
struct btrfs_log_ctx ctx;
int ret = 0, err;
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
u64 len;
bool full_sync;
Btrfs: add initial tracepoint support for btrfs Tracepoints can provide insight into why btrfs hits bugs and be greatly helpful for debugging, e.g dd-7822 [000] 2121.641088: btrfs_inode_request: root = 5(FS_TREE), gen = 4, ino = 256, blocks = 8, disk_i_size = 0, last_trans = 8, logged_trans = 0 dd-7822 [000] 2121.641100: btrfs_inode_new: root = 5(FS_TREE), gen = 8, ino = 257, blocks = 0, disk_i_size = 0, last_trans = 0, logged_trans = 0 btrfs-transacti-7804 [001] 2146.935420: btrfs_cow_block: root = 2(EXTENT_TREE), refs = 2, orig_buf = 29368320 (orig_level = 0), cow_buf = 29388800 (cow_level = 0) btrfs-transacti-7804 [001] 2146.935473: btrfs_cow_block: root = 1(ROOT_TREE), refs = 2, orig_buf = 29364224 (orig_level = 0), cow_buf = 29392896 (cow_level = 0) btrfs-transacti-7804 [001] 2146.972221: btrfs_transaction_commit: root = 1(ROOT_TREE), gen = 8 flush-btrfs-2-7821 [001] 2155.824210: btrfs_chunk_alloc: root = 3(CHUNK_TREE), offset = 1103101952, size = 1073741824, num_stripes = 1, sub_stripes = 0, type = DATA flush-btrfs-2-7821 [001] 2155.824241: btrfs_cow_block: root = 2(EXTENT_TREE), refs = 2, orig_buf = 29388800 (orig_level = 0), cow_buf = 29396992 (cow_level = 0) flush-btrfs-2-7821 [001] 2155.824255: btrfs_cow_block: root = 4(DEV_TREE), refs = 2, orig_buf = 29372416 (orig_level = 0), cow_buf = 29401088 (cow_level = 0) flush-btrfs-2-7821 [000] 2155.824329: btrfs_cow_block: root = 3(CHUNK_TREE), refs = 2, orig_buf = 20971520 (orig_level = 0), cow_buf = 20975616 (cow_level = 0) btrfs-endio-wri-7800 [001] 2155.898019: btrfs_cow_block: root = 5(FS_TREE), refs = 2, orig_buf = 29384704 (orig_level = 0), cow_buf = 29405184 (cow_level = 0) btrfs-endio-wri-7800 [001] 2155.898043: btrfs_cow_block: root = 7(CSUM_TREE), refs = 2, orig_buf = 29376512 (orig_level = 0), cow_buf = 29409280 (cow_level = 0) Here is what I have added: 1) ordere_extent: btrfs_ordered_extent_add btrfs_ordered_extent_remove btrfs_ordered_extent_start btrfs_ordered_extent_put These provide critical information to understand how ordered_extents are updated. 2) extent_map: btrfs_get_extent extent_map is used in both read and write cases, and it is useful for tracking how btrfs specific IO is running. 3) writepage: __extent_writepage btrfs_writepage_end_io_hook Pages are cirtical resourses and produce a lot of corner cases during writeback, so it is valuable to know how page is written to disk. 4) inode: btrfs_inode_new btrfs_inode_request btrfs_inode_evict These can show where and when a inode is created, when a inode is evicted. 5) sync: btrfs_sync_file btrfs_sync_fs These show sync arguments. 6) transaction: btrfs_transaction_commit In transaction based filesystem, it will be useful to know the generation and who does commit. 7) back reference and cow: btrfs_delayed_tree_ref btrfs_delayed_data_ref btrfs_delayed_ref_head btrfs_cow_block Btrfs natively supports back references, these tracepoints are helpful on understanding btrfs's COW mechanism. 8) chunk: btrfs_chunk_alloc btrfs_chunk_free Chunk is a link between physical offset and logical offset, and stands for space infomation in btrfs, and these are helpful on tracing space things. 9) reserved_extent: btrfs_reserved_extent_alloc btrfs_reserved_extent_free These can show how btrfs uses its space. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-03-24 19:18:59 +08:00
trace_btrfs_sync_file(file, datasync);
Btrfs: fix list_add corruption and soft lockups in fsync Xfstests btrfs/146 revealed this corruption, [ 58.138831] Buffer I/O error on dev dm-0, logical block 2621424, async page read [ 58.151233] BTRFS error (device sdf): bdev /dev/mapper/error-test errs: wr 1, rd 0, flush 0, corrupt 0, gen 0 [ 58.152403] list_add corruption. prev->next should be next (ffff88005e6775d8), but was ffffc9000189be88. (prev=ffffc9000189be88). [ 58.153518] ------------[ cut here ]------------ [ 58.153892] WARNING: CPU: 1 PID: 1287 at lib/list_debug.c:31 __list_add_valid+0x169/0x1f0 ... [ 58.157379] RIP: 0010:__list_add_valid+0x169/0x1f0 ... [ 58.161956] Call Trace: [ 58.162264] btrfs_log_inode_parent+0x5bd/0xfb0 [btrfs] [ 58.163583] btrfs_log_dentry_safe+0x60/0x80 [btrfs] [ 58.164003] btrfs_sync_file+0x4c2/0x6f0 [btrfs] [ 58.164393] vfs_fsync_range+0x5f/0xd0 [ 58.164898] do_fsync+0x5a/0x90 [ 58.165170] SyS_fsync+0x10/0x20 [ 58.165395] entry_SYSCALL_64_fastpath+0x1f/0xbe ... It turns out that we could record btrfs_log_ctx:io_err in log_one_extents when IO fails, but make log_one_extents() return '0' instead of -EIO, so the IO error is not acknowledged by the callers, i.e. btrfs_log_inode_parent(), which would remove btrfs_log_ctx:list from list head 'root->log_ctxs'. Since btrfs_log_ctx is allocated from stack memory, it'd get freed with a object alive on the list. then a future list_add will throw the above warning. This returns the correct error in the above case. Jeff also reported this while testing against his fsync error patch set[1]. [1]: https://www.spinics.net/lists/linux-btrfs/msg65308.html "btrfs list corruption and soft lockups while testing writeback error handling" Fixes: 8407f553268a4611f254 ("Btrfs: fix data corruption after fast fsync and writeback error") Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-22 05:35:40 +08:00
btrfs_init_log_ctx(&ctx, inode);
btrfs: fix missing file extent item for hole after ranged fsync When doing a fast fsync for a range that starts at an offset greater than zero, we can end up with a log that when replayed causes the respective inode miss a file extent item representing a hole if we are not using the NO_HOLES feature. This is because for fast fsyncs we don't log any extents that cover a range different from the one requested in the fsync. Example scenario to trigger it: $ mkfs.btrfs -O ^no-holes -f /dev/sdd $ mount /dev/sdd /mnt # Create a file with a single 256K and fsync it to clear to full sync # bit in the inode - we want the msync below to trigger a fast fsync. $ xfs_io -f -c "pwrite -S 0xab 0 256K" -c "fsync" /mnt/foo # Force a transaction commit and wipe out the log tree. $ sync # Dirty 768K of data, increasing the file size to 1Mb, and flush only # the range from 256K to 512K without updating the log tree # (sync_file_range() does not trigger fsync, it only starts writeback # and waits for it to finish). $ xfs_io -c "pwrite -S 0xcd 256K 768K" /mnt/foo $ xfs_io -c "sync_range -abw 256K 256K" /mnt/foo # Now dirty the range from 768K to 1M again and sync that range. $ xfs_io -c "mmap -w 768K 256K" \ -c "mwrite -S 0xef 768K 256K" \ -c "msync -s 768K 256K" \ -c "munmap" \ /mnt/foo <power fail> # Mount to replay the log. $ mount /dev/sdd /mnt $ umount /mnt $ btrfs check /dev/sdd Opening filesystem to check... Checking filesystem on /dev/sdd UUID: 482fb574-b288-478e-a190-a9c44a78fca6 [1/7] checking root items [2/7] checking extents [3/7] checking free space cache [4/7] checking fs roots root 5 inode 257 errors 100, file extent discount Found file extent holes: start: 262144, len: 524288 ERROR: errors found in fs roots found 720896 bytes used, error(s) found total csum bytes: 512 total tree bytes: 131072 total fs tree bytes: 32768 total extent tree bytes: 16384 btree space waste bytes: 123514 file data blocks allocated: 589824 referenced 589824 Fix this issue by setting the range to full (0 to LLONG_MAX) when the NO_HOLES feature is not enabled. This results in extra work being done but it gives the guarantee we don't end up with missing holes after replaying the log. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-09 20:41:05 +08:00
/*
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
* Always set the range to a full range, otherwise we can get into
* several problems, from missing file extent items to represent holes
* when not using the NO_HOLES feature, to log tree corruption due to
* races between hole detection during logging and completion of ordered
* extents outside the range, to missing checksums due to ordered extents
* for which we flushed only a subset of their pages.
btrfs: fix missing file extent item for hole after ranged fsync When doing a fast fsync for a range that starts at an offset greater than zero, we can end up with a log that when replayed causes the respective inode miss a file extent item representing a hole if we are not using the NO_HOLES feature. This is because for fast fsyncs we don't log any extents that cover a range different from the one requested in the fsync. Example scenario to trigger it: $ mkfs.btrfs -O ^no-holes -f /dev/sdd $ mount /dev/sdd /mnt # Create a file with a single 256K and fsync it to clear to full sync # bit in the inode - we want the msync below to trigger a fast fsync. $ xfs_io -f -c "pwrite -S 0xab 0 256K" -c "fsync" /mnt/foo # Force a transaction commit and wipe out the log tree. $ sync # Dirty 768K of data, increasing the file size to 1Mb, and flush only # the range from 256K to 512K without updating the log tree # (sync_file_range() does not trigger fsync, it only starts writeback # and waits for it to finish). $ xfs_io -c "pwrite -S 0xcd 256K 768K" /mnt/foo $ xfs_io -c "sync_range -abw 256K 256K" /mnt/foo # Now dirty the range from 768K to 1M again and sync that range. $ xfs_io -c "mmap -w 768K 256K" \ -c "mwrite -S 0xef 768K 256K" \ -c "msync -s 768K 256K" \ -c "munmap" \ /mnt/foo <power fail> # Mount to replay the log. $ mount /dev/sdd /mnt $ umount /mnt $ btrfs check /dev/sdd Opening filesystem to check... Checking filesystem on /dev/sdd UUID: 482fb574-b288-478e-a190-a9c44a78fca6 [1/7] checking root items [2/7] checking extents [3/7] checking free space cache [4/7] checking fs roots root 5 inode 257 errors 100, file extent discount Found file extent holes: start: 262144, len: 524288 ERROR: errors found in fs roots found 720896 bytes used, error(s) found total csum bytes: 512 total tree bytes: 131072 total fs tree bytes: 32768 total extent tree bytes: 16384 btree space waste bytes: 123514 file data blocks allocated: 589824 referenced 589824 Fix this issue by setting the range to full (0 to LLONG_MAX) when the NO_HOLES feature is not enabled. This results in extra work being done but it gives the guarantee we don't end up with missing holes after replaying the log. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-09 20:41:05 +08:00
*/
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
start = 0;
end = LLONG_MAX;
len = (u64)LLONG_MAX + 1;
btrfs: fix missing file extent item for hole after ranged fsync When doing a fast fsync for a range that starts at an offset greater than zero, we can end up with a log that when replayed causes the respective inode miss a file extent item representing a hole if we are not using the NO_HOLES feature. This is because for fast fsyncs we don't log any extents that cover a range different from the one requested in the fsync. Example scenario to trigger it: $ mkfs.btrfs -O ^no-holes -f /dev/sdd $ mount /dev/sdd /mnt # Create a file with a single 256K and fsync it to clear to full sync # bit in the inode - we want the msync below to trigger a fast fsync. $ xfs_io -f -c "pwrite -S 0xab 0 256K" -c "fsync" /mnt/foo # Force a transaction commit and wipe out the log tree. $ sync # Dirty 768K of data, increasing the file size to 1Mb, and flush only # the range from 256K to 512K without updating the log tree # (sync_file_range() does not trigger fsync, it only starts writeback # and waits for it to finish). $ xfs_io -c "pwrite -S 0xcd 256K 768K" /mnt/foo $ xfs_io -c "sync_range -abw 256K 256K" /mnt/foo # Now dirty the range from 768K to 1M again and sync that range. $ xfs_io -c "mmap -w 768K 256K" \ -c "mwrite -S 0xef 768K 256K" \ -c "msync -s 768K 256K" \ -c "munmap" \ /mnt/foo <power fail> # Mount to replay the log. $ mount /dev/sdd /mnt $ umount /mnt $ btrfs check /dev/sdd Opening filesystem to check... Checking filesystem on /dev/sdd UUID: 482fb574-b288-478e-a190-a9c44a78fca6 [1/7] checking root items [2/7] checking extents [3/7] checking free space cache [4/7] checking fs roots root 5 inode 257 errors 100, file extent discount Found file extent holes: start: 262144, len: 524288 ERROR: errors found in fs roots found 720896 bytes used, error(s) found total csum bytes: 512 total tree bytes: 131072 total fs tree bytes: 32768 total extent tree bytes: 16384 btree space waste bytes: 123514 file data blocks allocated: 589824 referenced 589824 Fix this issue by setting the range to full (0 to LLONG_MAX) when the NO_HOLES feature is not enabled. This results in extra work being done but it gives the guarantee we don't end up with missing holes after replaying the log. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-09 20:41:05 +08:00
/*
* We write the dirty pages in the range and wait until they complete
* out of the ->i_mutex. If so, we can flush the dirty pages by
* multi-task, and make the performance up. See
* btrfs_wait_ordered_range for an explanation of the ASYNC check.
*/
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
ret = start_ordered_ops(inode, start, end);
if (ret)
goto out;
btrfs: fix race between memory mapped writes and fsync When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush any new delalloc that might have been created before taking the lock and then wait either for the ordered extents to complete or just for the writeback to complete (depending on whether the full sync flag is set or not). We then start logging the inode and assume that while we are doing it no one else is touching the inode's file extent items (or adding new ones). That is generally true because all operations that modify an inode acquire the inode's lock first, including buffered and direct IO writes. However there is one exception: memory mapped writes, which do not and can not acquire the inode's lock. This can cause two types of issues: ending up logging file extent items with overlapping ranges, which is detected by the tree checker and will result in aborting the transaction when starting writeback for a log tree's extent buffers, or a silent corruption where we log a version of the file that never existed. Scenario 1 - logging overlapping extents The following steps explain how we can end up with file extents items with overlapping ranges in a log tree due to a race between a fsync and memory mapped writes: 1) Task A starts an fsync on inode X, which has the full sync runtime flag set. First it starts by flushing all delalloc for the inode; 2) Task A then locks the inode and flushes any other delalloc that might have been created after the previous flush and waits for all ordered extents to complete; 3) In the inode's root we have the following leaf: Leaf N, generation == current transaction id: --------------------------------------------------------- | (...) [ file extent item, offset 640K, length 128K ] | --------------------------------------------------------- The last file extent item in leaf N covers the file range from 640K to 768K; 4) Task B does a memory mapped write for the page corresponding to the file range from 764K to 768K; 5) Task A starts logging the inode. At copy_inode_items_to_log() it uses btrfs_search_forward() to search for leafs modified in the current transaction that contain items for the inode. It finds leaf N and copies all the inode items from that leaf into the log tree. Now the log tree has a copy of the last file extent item from leaf N. At the end of the while loop at copy_inode_items_to_log(), we have the minimum key set to: min_key.objectid = <inode X number> min_key.type = BTRFS_EXTENT_DATA_KEY min_key.offset = 640K Then we increment the key's offset by 1 so that the next call to btrfs_search_forward() leaves us at the first key greater than the key we just processed. But before btrfs_search_forward() is called again... 6) Dellaloc for the page at offset 764K, dirtied by task B, is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) When the respective ordered extent completes, it trims the length of the existing file extent item for file offset 640K from 128K to 124K, and a new file extent item is added with a key offset of 764K and a length of 4K; 8) Task A calls btrfs_search_forward(), which returns us a path pointing to the leaf (can be leaf N or some other) containing the new file extent item for file offset 764K. We end up copying this item to the log tree, which overlaps with the last copied file extent item, which covers the file range from 640K to 768K. When writeback is triggered for log tree's extent buffers, the issue will be detected by the tree checker which will dump a trace and an error message on dmesg/syslog. If the writeback is triggered when syncing the log, which typically is, then we also end up aborting the current transaction. This is the same type of problem fixed in 0c713cbab6200b ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"). Scenario 2 - logging a version of the file that never existed This scenario only happens when using the NO_HOLES feature and results in a silent corruption, in the sense that is not detectable by 'btrfs check' or the tree checker: 1) We have an inode I with a size of 1M and two file extent items, one covering an extent with disk_bytenr == X for the file range [0, 512K) and another one covering another extent with disk_bytenr == Y for the file range [512K, 1M); 2) A hole is punched for the file range [512K, 1M); 3) Task A starts an fsync of inode I, which has the full sync runtime flag set. It starts by flushing all existing delalloc, locks the inode (VFS lock), starts any new delalloc that might have been created before taking the lock and waits for all ordered extents to complete; 4) Some other task does a memory mapped write for the page corresponding to the file range [640K, 644K) for example; 5) Task A then logs all items of the inode with the call to copy_inode_items_to_log(); 6) In the meanwhile delalloc for the range [640K, 644K) is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) The ordered extent for the range [640K, 644K) completes and a file extent item for that range is added to the subvolume tree, pointing to a 4K extent with a disk_bytenr == Z; 8) Task A then calls btrfs_log_holes(), to scan for implicit holes in the subvolume tree. It finds two implicit holes: - one for the file range [512K, 640K) - one for the file range [644K, 1M) As a result we end up neither logging a hole for the range [640K, 644K) nor logging the file extent item with a disk_bytenr == Z. This means that if we have a power failure and replay the log tree we end up getting the following file extent layout: [ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M Which does not corresponding to any layout the file ever had before the power failure. The only two valid layouts would be: [ disk_bytenr X ] [ hole ] 0 512K 512K 1M and [ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M This can be fixed by serializing memory mapped writes with fsync, and there are two ways to do it: 1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX in the inode's io tree. This prevents the race but also blocks any reads during the duration of the fsync, which has a negative impact for many common workloads; 2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This semaphore was recently added by Josef's patch set: btrfs: add a i_mmap_lock to our inode btrfs: cleanup inode_lock/inode_unlock uses btrfs: exclude mmaps while doing remap btrfs: exclude mmap from happening during all fallocate operations and is used to solve races between memory mapped writes and clone/dedupe/fallocate. This also makes us have the same behaviour we have regarding other writes (buffered and direct IO) and fsync - block them while the inode logging is in progress. This change uses the second approach due to the performance impact of the first one. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-23 20:08:47 +08:00
btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
btrfs: move the dio_sem higher up the callchain We're getting a lockdep splat because we take the dio_sem under the log_mutex. What we really need is to protect fsync() from logging an extent map for an extent we never waited on higher up, so just guard the whole thing with dio_sem. ====================================================== WARNING: possible circular locking dependency detected 4.18.0-rc4-xfstests-00025-g5de5edbaf1d4 #411 Not tainted ------------------------------------------------------ aio-dio-invalid/30928 is trying to acquire lock: 0000000092621cfd (&mm->mmap_sem){++++}, at: get_user_pages_unlocked+0x5a/0x1e0 but task is already holding lock: 00000000cefe6b35 (&ei->dio_sem){++++}, at: btrfs_direct_IO+0x3be/0x400 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&ei->dio_sem){++++}: lock_acquire+0xbd/0x220 down_write+0x51/0xb0 btrfs_log_changed_extents+0x80/0xa40 btrfs_log_inode+0xbaf/0x1000 btrfs_log_inode_parent+0x26f/0xa80 btrfs_log_dentry_safe+0x50/0x70 btrfs_sync_file+0x357/0x540 do_fsync+0x38/0x60 __ia32_sys_fdatasync+0x12/0x20 do_fast_syscall_32+0x9a/0x2f0 entry_SYSENTER_compat+0x84/0x96 -> #4 (&ei->log_mutex){+.+.}: lock_acquire+0xbd/0x220 __mutex_lock+0x86/0xa10 btrfs_record_unlink_dir+0x2a/0xa0 btrfs_unlink+0x5a/0xc0 vfs_unlink+0xb1/0x1a0 do_unlinkat+0x264/0x2b0 do_fast_syscall_32+0x9a/0x2f0 entry_SYSENTER_compat+0x84/0x96 -> #3 (sb_internal#2){.+.+}: lock_acquire+0xbd/0x220 __sb_start_write+0x14d/0x230 start_transaction+0x3e6/0x590 btrfs_evict_inode+0x475/0x640 evict+0xbf/0x1b0 btrfs_run_delayed_iputs+0x6c/0x90 cleaner_kthread+0x124/0x1a0 kthread+0x106/0x140 ret_from_fork+0x3a/0x50 -> #2 (&fs_info->cleaner_delayed_iput_mutex){+.+.}: lock_acquire+0xbd/0x220 __mutex_lock+0x86/0xa10 btrfs_alloc_data_chunk_ondemand+0x197/0x530 btrfs_check_data_free_space+0x4c/0x90 btrfs_delalloc_reserve_space+0x20/0x60 btrfs_page_mkwrite+0x87/0x520 do_page_mkwrite+0x31/0xa0 __handle_mm_fault+0x799/0xb00 handle_mm_fault+0x7c/0xe0 __do_page_fault+0x1d3/0x4a0 async_page_fault+0x1e/0x30 -> #1 (sb_pagefaults){.+.+}: lock_acquire+0xbd/0x220 __sb_start_write+0x14d/0x230 btrfs_page_mkwrite+0x6a/0x520 do_page_mkwrite+0x31/0xa0 __handle_mm_fault+0x799/0xb00 handle_mm_fault+0x7c/0xe0 __do_page_fault+0x1d3/0x4a0 async_page_fault+0x1e/0x30 -> #0 (&mm->mmap_sem){++++}: __lock_acquire+0x42e/0x7a0 lock_acquire+0xbd/0x220 down_read+0x48/0xb0 get_user_pages_unlocked+0x5a/0x1e0 get_user_pages_fast+0xa4/0x150 iov_iter_get_pages+0xc3/0x340 do_direct_IO+0xf93/0x1d70 __blockdev_direct_IO+0x32d/0x1c20 btrfs_direct_IO+0x227/0x400 generic_file_direct_write+0xcf/0x180 btrfs_file_write_iter+0x308/0x58c aio_write+0xf8/0x1d0 io_submit_one+0x3a9/0x620 __ia32_compat_sys_io_submit+0xb2/0x270 do_int80_syscall_32+0x5b/0x1a0 entry_INT80_compat+0x88/0xa0 other info that might help us debug this: Chain exists of: &mm->mmap_sem --> &ei->log_mutex --> &ei->dio_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->dio_sem); lock(&ei->log_mutex); lock(&ei->dio_sem); lock(&mm->mmap_sem); *** DEADLOCK *** 1 lock held by aio-dio-invalid/30928: #0: 00000000cefe6b35 (&ei->dio_sem){++++}, at: btrfs_direct_IO+0x3be/0x400 stack backtrace: CPU: 0 PID: 30928 Comm: aio-dio-invalid Not tainted 4.18.0-rc4-xfstests-00025-g5de5edbaf1d4 #411 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 Call Trace: dump_stack+0x7c/0xbb print_circular_bug.isra.37+0x297/0x2a4 check_prev_add.constprop.45+0x781/0x7a0 ? __lock_acquire+0x42e/0x7a0 validate_chain.isra.41+0x7f0/0xb00 __lock_acquire+0x42e/0x7a0 lock_acquire+0xbd/0x220 ? get_user_pages_unlocked+0x5a/0x1e0 down_read+0x48/0xb0 ? get_user_pages_unlocked+0x5a/0x1e0 get_user_pages_unlocked+0x5a/0x1e0 get_user_pages_fast+0xa4/0x150 iov_iter_get_pages+0xc3/0x340 do_direct_IO+0xf93/0x1d70 ? __alloc_workqueue_key+0x358/0x490 ? __blockdev_direct_IO+0x14b/0x1c20 __blockdev_direct_IO+0x32d/0x1c20 ? btrfs_run_delalloc_work+0x40/0x40 ? can_nocow_extent+0x490/0x490 ? kvm_clock_read+0x1f/0x30 ? can_nocow_extent+0x490/0x490 ? btrfs_run_delalloc_work+0x40/0x40 btrfs_direct_IO+0x227/0x400 ? btrfs_run_delalloc_work+0x40/0x40 generic_file_direct_write+0xcf/0x180 btrfs_file_write_iter+0x308/0x58c aio_write+0xf8/0x1d0 ? kvm_clock_read+0x1f/0x30 ? __might_fault+0x3e/0x90 io_submit_one+0x3a9/0x620 ? io_submit_one+0xe5/0x620 __ia32_compat_sys_io_submit+0xb2/0x270 do_int80_syscall_32+0x5b/0x1a0 entry_INT80_compat+0x88/0xa0 CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-13 03:32:32 +08:00
atomic_inc(&root->log_batch);
btrfs: make full fsyncs always operate on the entire file again This is a revert of commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient"), with updated comment in btrfs_sync_file. Commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") made full fsyncs operate on the given range only as it assumed it was safe when using the NO_HOLES feature, since the hole detection was simplified some time ago and no longer was a source for races with ordered extent completion of adjacent file ranges. However it's still not safe to have a full fsync only operate on the given range, because extent maps for new extents might not be present in memory due to inode eviction or extent cloning. Consider the following example: 1) We are currently at transaction N; 2) We write to the file range [0, 1MiB); 3) Writeback finishes for the whole range and ordered extents complete, while we are still at transaction N; 4) The inode is evicted; 5) We open the file for writing, causing the inode to be loaded to memory again, which sets the 'full sync' bit on its flags. At this point the inode's list of modified extent maps is empty (figuring out which extents were created in the current transaction and were not yet logged by an fsync is expensive, that's why we set the 'full sync' bit when loading an inode); 6) We write to the file range [512KiB, 768KiB); 7) We do a ranged fsync (such as msync()) for file range [512KiB, 768KiB). This correctly flushes this range and logs its extent into the log tree. When the writeback started an extent map for range [512KiB, 768KiB) was added to the inode's list of modified extents, and when the fsync() finishes logging it removes that extent map from the list of modified extent maps. This fsync also clears the 'full sync' bit; 8) We do a regular fsync() (full ranged). This fsync() ends up doing nothing because the inode's list of modified extents is empty and no other changes happened since the previous ranged fsync(), so it just returns success (0) and we end up never logging extents for the file ranges [0, 512KiB) and [768KiB, 1MiB). Another scenario where this can happen is if we replace steps 2 to 4 with cloning from another file into our test file, as that sets the 'full sync' bit in our inode's flags and does not populate its list of modified extent maps. This was causing test case generic/457 to fail sporadically when using the NO_HOLES feature, as it exercised this later case where the inode has the 'full sync' bit set and has no extent maps in memory to represent the new extents due to extent cloning. Fix this by reverting commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") since there is no easy way to work around it. Fixes: 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-04-07 18:37:44 +08:00
/*
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
* Always check for the full sync flag while holding the inode's lock,
* to avoid races with other tasks. The flag must be either set all the
* time during logging or always off all the time while logging.
btrfs: make full fsyncs always operate on the entire file again This is a revert of commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient"), with updated comment in btrfs_sync_file. Commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") made full fsyncs operate on the given range only as it assumed it was safe when using the NO_HOLES feature, since the hole detection was simplified some time ago and no longer was a source for races with ordered extent completion of adjacent file ranges. However it's still not safe to have a full fsync only operate on the given range, because extent maps for new extents might not be present in memory due to inode eviction or extent cloning. Consider the following example: 1) We are currently at transaction N; 2) We write to the file range [0, 1MiB); 3) Writeback finishes for the whole range and ordered extents complete, while we are still at transaction N; 4) The inode is evicted; 5) We open the file for writing, causing the inode to be loaded to memory again, which sets the 'full sync' bit on its flags. At this point the inode's list of modified extent maps is empty (figuring out which extents were created in the current transaction and were not yet logged by an fsync is expensive, that's why we set the 'full sync' bit when loading an inode); 6) We write to the file range [512KiB, 768KiB); 7) We do a ranged fsync (such as msync()) for file range [512KiB, 768KiB). This correctly flushes this range and logs its extent into the log tree. When the writeback started an extent map for range [512KiB, 768KiB) was added to the inode's list of modified extents, and when the fsync() finishes logging it removes that extent map from the list of modified extent maps. This fsync also clears the 'full sync' bit; 8) We do a regular fsync() (full ranged). This fsync() ends up doing nothing because the inode's list of modified extents is empty and no other changes happened since the previous ranged fsync(), so it just returns success (0) and we end up never logging extents for the file ranges [0, 512KiB) and [768KiB, 1MiB). Another scenario where this can happen is if we replace steps 2 to 4 with cloning from another file into our test file, as that sets the 'full sync' bit in our inode's flags and does not populate its list of modified extent maps. This was causing test case generic/457 to fail sporadically when using the NO_HOLES feature, as it exercised this later case where the inode has the 'full sync' bit set and has no extent maps in memory to represent the new extents due to extent cloning. Fix this by reverting commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") since there is no easy way to work around it. Fixes: 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-04-07 18:37:44 +08:00
*/
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
btrfs: make full fsyncs always operate on the entire file again This is a revert of commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient"), with updated comment in btrfs_sync_file. Commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") made full fsyncs operate on the given range only as it assumed it was safe when using the NO_HOLES feature, since the hole detection was simplified some time ago and no longer was a source for races with ordered extent completion of adjacent file ranges. However it's still not safe to have a full fsync only operate on the given range, because extent maps for new extents might not be present in memory due to inode eviction or extent cloning. Consider the following example: 1) We are currently at transaction N; 2) We write to the file range [0, 1MiB); 3) Writeback finishes for the whole range and ordered extents complete, while we are still at transaction N; 4) The inode is evicted; 5) We open the file for writing, causing the inode to be loaded to memory again, which sets the 'full sync' bit on its flags. At this point the inode's list of modified extent maps is empty (figuring out which extents were created in the current transaction and were not yet logged by an fsync is expensive, that's why we set the 'full sync' bit when loading an inode); 6) We write to the file range [512KiB, 768KiB); 7) We do a ranged fsync (such as msync()) for file range [512KiB, 768KiB). This correctly flushes this range and logs its extent into the log tree. When the writeback started an extent map for range [512KiB, 768KiB) was added to the inode's list of modified extents, and when the fsync() finishes logging it removes that extent map from the list of modified extent maps. This fsync also clears the 'full sync' bit; 8) We do a regular fsync() (full ranged). This fsync() ends up doing nothing because the inode's list of modified extents is empty and no other changes happened since the previous ranged fsync(), so it just returns success (0) and we end up never logging extents for the file ranges [0, 512KiB) and [768KiB, 1MiB). Another scenario where this can happen is if we replace steps 2 to 4 with cloning from another file into our test file, as that sets the 'full sync' bit in our inode's flags and does not populate its list of modified extent maps. This was causing test case generic/457 to fail sporadically when using the NO_HOLES feature, as it exercised this later case where the inode has the 'full sync' bit set and has no extent maps in memory to represent the new extents due to extent cloning. Fix this by reverting commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") since there is no easy way to work around it. Fixes: 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-04-07 18:37:44 +08:00
Btrfs: fix rare chances for data loss when doing a fast fsync After the simplification of the fast fsync patch done recently by commit b5e6c3e170b7 ("btrfs: always wait on ordered extents at fsync time") and commit e7175a692765 ("btrfs: remove the wait ordered logic in the log_one_extent path"), we got a very short time window where we can get extents logged without writeback completing first or extents logged without logging the respective data checksums. Both issues can only happen when doing a non-full (fast) fsync. As soon as we enter btrfs_sync_file() we trigger writeback, then lock the inode and then wait for the writeback to complete before starting to log the inode. However before we acquire the inode's lock and after we started writeback, it's possible that more writes happened and dirtied more pages. If that happened and those pages get writeback triggered while we are logging the inode (for example, the VM subsystem triggering it due to memory pressure, or another concurrent fsync), we end up seeing the respective extent maps in the inode's list of modified extents and will log matching file extent items without waiting for the respective ordered extents to complete, meaning that either of the following will happen: 1) We log an extent after its writeback finishes but before its checksums are added to the csum tree, leading to -EIO errors when attempting to read the extent after a log replay. 2) We log an extent before its writeback finishes. Therefore after the log replay we will have a file extent item pointing to an unwritten extent (and without the respective data checksums as well). This could not happen before the fast fsync patch simplification, because for any extent we found in the list of modified extents, we would wait for its respective ordered extent to finish writeback or collect its checksums for logging if it did not complete yet. Fix this by triggering writeback again after acquiring the inode's lock and before waiting for ordered extents to complete. Fixes: e7175a692765 ("btrfs: remove the wait ordered logic in the log_one_extent path") Fixes: b5e6c3e170b7 ("btrfs: always wait on ordered extents at fsync time") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-11-12 18:23:58 +08:00
/*
btrfs: fix race between memory mapped writes and fsync When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush any new delalloc that might have been created before taking the lock and then wait either for the ordered extents to complete or just for the writeback to complete (depending on whether the full sync flag is set or not). We then start logging the inode and assume that while we are doing it no one else is touching the inode's file extent items (or adding new ones). That is generally true because all operations that modify an inode acquire the inode's lock first, including buffered and direct IO writes. However there is one exception: memory mapped writes, which do not and can not acquire the inode's lock. This can cause two types of issues: ending up logging file extent items with overlapping ranges, which is detected by the tree checker and will result in aborting the transaction when starting writeback for a log tree's extent buffers, or a silent corruption where we log a version of the file that never existed. Scenario 1 - logging overlapping extents The following steps explain how we can end up with file extents items with overlapping ranges in a log tree due to a race between a fsync and memory mapped writes: 1) Task A starts an fsync on inode X, which has the full sync runtime flag set. First it starts by flushing all delalloc for the inode; 2) Task A then locks the inode and flushes any other delalloc that might have been created after the previous flush and waits for all ordered extents to complete; 3) In the inode's root we have the following leaf: Leaf N, generation == current transaction id: --------------------------------------------------------- | (...) [ file extent item, offset 640K, length 128K ] | --------------------------------------------------------- The last file extent item in leaf N covers the file range from 640K to 768K; 4) Task B does a memory mapped write for the page corresponding to the file range from 764K to 768K; 5) Task A starts logging the inode. At copy_inode_items_to_log() it uses btrfs_search_forward() to search for leafs modified in the current transaction that contain items for the inode. It finds leaf N and copies all the inode items from that leaf into the log tree. Now the log tree has a copy of the last file extent item from leaf N. At the end of the while loop at copy_inode_items_to_log(), we have the minimum key set to: min_key.objectid = <inode X number> min_key.type = BTRFS_EXTENT_DATA_KEY min_key.offset = 640K Then we increment the key's offset by 1 so that the next call to btrfs_search_forward() leaves us at the first key greater than the key we just processed. But before btrfs_search_forward() is called again... 6) Dellaloc for the page at offset 764K, dirtied by task B, is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) When the respective ordered extent completes, it trims the length of the existing file extent item for file offset 640K from 128K to 124K, and a new file extent item is added with a key offset of 764K and a length of 4K; 8) Task A calls btrfs_search_forward(), which returns us a path pointing to the leaf (can be leaf N or some other) containing the new file extent item for file offset 764K. We end up copying this item to the log tree, which overlaps with the last copied file extent item, which covers the file range from 640K to 768K. When writeback is triggered for log tree's extent buffers, the issue will be detected by the tree checker which will dump a trace and an error message on dmesg/syslog. If the writeback is triggered when syncing the log, which typically is, then we also end up aborting the current transaction. This is the same type of problem fixed in 0c713cbab6200b ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"). Scenario 2 - logging a version of the file that never existed This scenario only happens when using the NO_HOLES feature and results in a silent corruption, in the sense that is not detectable by 'btrfs check' or the tree checker: 1) We have an inode I with a size of 1M and two file extent items, one covering an extent with disk_bytenr == X for the file range [0, 512K) and another one covering another extent with disk_bytenr == Y for the file range [512K, 1M); 2) A hole is punched for the file range [512K, 1M); 3) Task A starts an fsync of inode I, which has the full sync runtime flag set. It starts by flushing all existing delalloc, locks the inode (VFS lock), starts any new delalloc that might have been created before taking the lock and waits for all ordered extents to complete; 4) Some other task does a memory mapped write for the page corresponding to the file range [640K, 644K) for example; 5) Task A then logs all items of the inode with the call to copy_inode_items_to_log(); 6) In the meanwhile delalloc for the range [640K, 644K) is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) The ordered extent for the range [640K, 644K) completes and a file extent item for that range is added to the subvolume tree, pointing to a 4K extent with a disk_bytenr == Z; 8) Task A then calls btrfs_log_holes(), to scan for implicit holes in the subvolume tree. It finds two implicit holes: - one for the file range [512K, 640K) - one for the file range [644K, 1M) As a result we end up neither logging a hole for the range [640K, 644K) nor logging the file extent item with a disk_bytenr == Z. This means that if we have a power failure and replay the log tree we end up getting the following file extent layout: [ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M Which does not corresponding to any layout the file ever had before the power failure. The only two valid layouts would be: [ disk_bytenr X ] [ hole ] 0 512K 512K 1M and [ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M This can be fixed by serializing memory mapped writes with fsync, and there are two ways to do it: 1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX in the inode's io tree. This prevents the race but also blocks any reads during the duration of the fsync, which has a negative impact for many common workloads; 2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This semaphore was recently added by Josef's patch set: btrfs: add a i_mmap_lock to our inode btrfs: cleanup inode_lock/inode_unlock uses btrfs: exclude mmaps while doing remap btrfs: exclude mmap from happening during all fallocate operations and is used to solve races between memory mapped writes and clone/dedupe/fallocate. This also makes us have the same behaviour we have regarding other writes (buffered and direct IO) and fsync - block them while the inode logging is in progress. This change uses the second approach due to the performance impact of the first one. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-23 20:08:47 +08:00
* Before we acquired the inode's lock and the mmap lock, someone may
* have dirtied more pages in the target range. We need to make sure
* that writeback for any such pages does not start while we are logging
* the inode, because if it does, any of the following might happen when
* we are not doing a full inode sync:
Btrfs: fix rare chances for data loss when doing a fast fsync After the simplification of the fast fsync patch done recently by commit b5e6c3e170b7 ("btrfs: always wait on ordered extents at fsync time") and commit e7175a692765 ("btrfs: remove the wait ordered logic in the log_one_extent path"), we got a very short time window where we can get extents logged without writeback completing first or extents logged without logging the respective data checksums. Both issues can only happen when doing a non-full (fast) fsync. As soon as we enter btrfs_sync_file() we trigger writeback, then lock the inode and then wait for the writeback to complete before starting to log the inode. However before we acquire the inode's lock and after we started writeback, it's possible that more writes happened and dirtied more pages. If that happened and those pages get writeback triggered while we are logging the inode (for example, the VM subsystem triggering it due to memory pressure, or another concurrent fsync), we end up seeing the respective extent maps in the inode's list of modified extents and will log matching file extent items without waiting for the respective ordered extents to complete, meaning that either of the following will happen: 1) We log an extent after its writeback finishes but before its checksums are added to the csum tree, leading to -EIO errors when attempting to read the extent after a log replay. 2) We log an extent before its writeback finishes. Therefore after the log replay we will have a file extent item pointing to an unwritten extent (and without the respective data checksums as well). This could not happen before the fast fsync patch simplification, because for any extent we found in the list of modified extents, we would wait for its respective ordered extent to finish writeback or collect its checksums for logging if it did not complete yet. Fix this by triggering writeback again after acquiring the inode's lock and before waiting for ordered extents to complete. Fixes: e7175a692765 ("btrfs: remove the wait ordered logic in the log_one_extent path") Fixes: b5e6c3e170b7 ("btrfs: always wait on ordered extents at fsync time") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-11-12 18:23:58 +08:00
*
* 1) We log an extent after its writeback finishes but before its
* checksums are added to the csum tree, leading to -EIO errors
* when attempting to read the extent after a log replay.
*
* 2) We can end up logging an extent before its writeback finishes.
* Therefore after the log replay we will have a file extent item
* pointing to an unwritten extent (and no data checksums as well).
*
* So trigger writeback for any eventual new dirty pages and then we
* wait for all ordered extents to complete below.
*/
ret = start_ordered_ops(inode, start, end);
if (ret) {
btrfs: fix race between memory mapped writes and fsync When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush any new delalloc that might have been created before taking the lock and then wait either for the ordered extents to complete or just for the writeback to complete (depending on whether the full sync flag is set or not). We then start logging the inode and assume that while we are doing it no one else is touching the inode's file extent items (or adding new ones). That is generally true because all operations that modify an inode acquire the inode's lock first, including buffered and direct IO writes. However there is one exception: memory mapped writes, which do not and can not acquire the inode's lock. This can cause two types of issues: ending up logging file extent items with overlapping ranges, which is detected by the tree checker and will result in aborting the transaction when starting writeback for a log tree's extent buffers, or a silent corruption where we log a version of the file that never existed. Scenario 1 - logging overlapping extents The following steps explain how we can end up with file extents items with overlapping ranges in a log tree due to a race between a fsync and memory mapped writes: 1) Task A starts an fsync on inode X, which has the full sync runtime flag set. First it starts by flushing all delalloc for the inode; 2) Task A then locks the inode and flushes any other delalloc that might have been created after the previous flush and waits for all ordered extents to complete; 3) In the inode's root we have the following leaf: Leaf N, generation == current transaction id: --------------------------------------------------------- | (...) [ file extent item, offset 640K, length 128K ] | --------------------------------------------------------- The last file extent item in leaf N covers the file range from 640K to 768K; 4) Task B does a memory mapped write for the page corresponding to the file range from 764K to 768K; 5) Task A starts logging the inode. At copy_inode_items_to_log() it uses btrfs_search_forward() to search for leafs modified in the current transaction that contain items for the inode. It finds leaf N and copies all the inode items from that leaf into the log tree. Now the log tree has a copy of the last file extent item from leaf N. At the end of the while loop at copy_inode_items_to_log(), we have the minimum key set to: min_key.objectid = <inode X number> min_key.type = BTRFS_EXTENT_DATA_KEY min_key.offset = 640K Then we increment the key's offset by 1 so that the next call to btrfs_search_forward() leaves us at the first key greater than the key we just processed. But before btrfs_search_forward() is called again... 6) Dellaloc for the page at offset 764K, dirtied by task B, is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) When the respective ordered extent completes, it trims the length of the existing file extent item for file offset 640K from 128K to 124K, and a new file extent item is added with a key offset of 764K and a length of 4K; 8) Task A calls btrfs_search_forward(), which returns us a path pointing to the leaf (can be leaf N or some other) containing the new file extent item for file offset 764K. We end up copying this item to the log tree, which overlaps with the last copied file extent item, which covers the file range from 640K to 768K. When writeback is triggered for log tree's extent buffers, the issue will be detected by the tree checker which will dump a trace and an error message on dmesg/syslog. If the writeback is triggered when syncing the log, which typically is, then we also end up aborting the current transaction. This is the same type of problem fixed in 0c713cbab6200b ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"). Scenario 2 - logging a version of the file that never existed This scenario only happens when using the NO_HOLES feature and results in a silent corruption, in the sense that is not detectable by 'btrfs check' or the tree checker: 1) We have an inode I with a size of 1M and two file extent items, one covering an extent with disk_bytenr == X for the file range [0, 512K) and another one covering another extent with disk_bytenr == Y for the file range [512K, 1M); 2) A hole is punched for the file range [512K, 1M); 3) Task A starts an fsync of inode I, which has the full sync runtime flag set. It starts by flushing all existing delalloc, locks the inode (VFS lock), starts any new delalloc that might have been created before taking the lock and waits for all ordered extents to complete; 4) Some other task does a memory mapped write for the page corresponding to the file range [640K, 644K) for example; 5) Task A then logs all items of the inode with the call to copy_inode_items_to_log(); 6) In the meanwhile delalloc for the range [640K, 644K) is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) The ordered extent for the range [640K, 644K) completes and a file extent item for that range is added to the subvolume tree, pointing to a 4K extent with a disk_bytenr == Z; 8) Task A then calls btrfs_log_holes(), to scan for implicit holes in the subvolume tree. It finds two implicit holes: - one for the file range [512K, 640K) - one for the file range [644K, 1M) As a result we end up neither logging a hole for the range [640K, 644K) nor logging the file extent item with a disk_bytenr == Z. This means that if we have a power failure and replay the log tree we end up getting the following file extent layout: [ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M Which does not corresponding to any layout the file ever had before the power failure. The only two valid layouts would be: [ disk_bytenr X ] [ hole ] 0 512K 512K 1M and [ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M This can be fixed by serializing memory mapped writes with fsync, and there are two ways to do it: 1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX in the inode's io tree. This prevents the race but also blocks any reads during the duration of the fsync, which has a negative impact for many common workloads; 2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This semaphore was recently added by Josef's patch set: btrfs: add a i_mmap_lock to our inode btrfs: cleanup inode_lock/inode_unlock uses btrfs: exclude mmaps while doing remap btrfs: exclude mmap from happening during all fallocate operations and is used to solve races between memory mapped writes and clone/dedupe/fallocate. This also makes us have the same behaviour we have regarding other writes (buffered and direct IO) and fsync - block them while the inode logging is in progress. This change uses the second approach due to the performance impact of the first one. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-23 20:08:47 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
Btrfs: fix rare chances for data loss when doing a fast fsync After the simplification of the fast fsync patch done recently by commit b5e6c3e170b7 ("btrfs: always wait on ordered extents at fsync time") and commit e7175a692765 ("btrfs: remove the wait ordered logic in the log_one_extent path"), we got a very short time window where we can get extents logged without writeback completing first or extents logged without logging the respective data checksums. Both issues can only happen when doing a non-full (fast) fsync. As soon as we enter btrfs_sync_file() we trigger writeback, then lock the inode and then wait for the writeback to complete before starting to log the inode. However before we acquire the inode's lock and after we started writeback, it's possible that more writes happened and dirtied more pages. If that happened and those pages get writeback triggered while we are logging the inode (for example, the VM subsystem triggering it due to memory pressure, or another concurrent fsync), we end up seeing the respective extent maps in the inode's list of modified extents and will log matching file extent items without waiting for the respective ordered extents to complete, meaning that either of the following will happen: 1) We log an extent after its writeback finishes but before its checksums are added to the csum tree, leading to -EIO errors when attempting to read the extent after a log replay. 2) We log an extent before its writeback finishes. Therefore after the log replay we will have a file extent item pointing to an unwritten extent (and without the respective data checksums as well). This could not happen before the fast fsync patch simplification, because for any extent we found in the list of modified extents, we would wait for its respective ordered extent to finish writeback or collect its checksums for logging if it did not complete yet. Fix this by triggering writeback again after acquiring the inode's lock and before waiting for ordered extents to complete. Fixes: e7175a692765 ("btrfs: remove the wait ordered logic in the log_one_extent path") Fixes: b5e6c3e170b7 ("btrfs: always wait on ordered extents at fsync time") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-11-12 18:23:58 +08:00
goto out;
}
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
/*
* We have to do this here to avoid the priority inversion of waiting on
* IO of a lower priority task while holding a transaction open.
*
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
* For a full fsync we wait for the ordered extents to complete while
* for a fast fsync we wait just for writeback to complete, and then
* attach the ordered extents to the transaction so that a transaction
* commit waits for their completion, to avoid data loss if we fsync,
* the current transaction commits before the ordered extents complete
* and a power failure happens right after that.
*
* For zoned filesystem, if a write IO uses a ZONE_APPEND command, the
* logical address recorded in the ordered extent may change. We need
* to wait for the IO to stabilize the logical address.
Btrfs: fix fsync race leading to invalid data after log replay When the fsync callback (btrfs_sync_file) starts, it first waits for the writeback of any dirty pages to start and finish without holding the inode's mutex (to reduce contention). After this it acquires the inode's mutex and repeats that process via btrfs_wait_ordered_range only if we're doing a full sync (BTRFS_INODE_NEEDS_FULL_SYNC flag is set on the inode). This is not safe for a non full sync - we need to start and wait for writeback to finish for any pages that might have been made dirty before acquiring the inode's mutex and after that first step mentioned before. Why this is needed is explained by the following comment added to btrfs_sync_file: "Right before acquiring the inode's mutex, we might have new writes dirtying pages, which won't immediately start the respective ordered operations - that is done through the fill_delalloc callbacks invoked from the writepage and writepages address space operations. So make sure we start all ordered operations before starting to log our inode. Not doing this means that while logging the inode, writeback could start and invoke writepage/writepages, which would call the fill_delalloc callbacks (cow_file_range, submit_compressed_extents). These callbacks add first an extent map to the modified list of extents and then create the respective ordered operation, which means in tree-log.c:btrfs_log_inode() we might capture all existing ordered operations (with btrfs_get_logged_extents()) before the fill_delalloc callback adds its ordered operation, and by the time we visit the modified list of extent maps (with btrfs_log_changed_extents()), we see and process the extent map they created. We then use the extent map to construct a file extent item for logging without waiting for the respective ordered operation to finish - this file extent item points to a disk location that might not have yet been written to, containing random data - so after a crash a log replay will make our inode have file extent items that point to disk locations containing invalid data, as we returned success to userspace without waiting for the respective ordered operation to finish, because it wasn't captured by btrfs_get_logged_extents()." Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-02 18:09:58 +08:00
*/
if (full_sync || btrfs_is_zoned(fs_info)) {
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
ret = btrfs_wait_ordered_range(inode, start, len);
} else {
/*
* Get our ordered extents as soon as possible to avoid doing
* checksum lookups in the csum tree, and use instead the
* checksums attached to the ordered extents.
*/
btrfs_get_ordered_extents_for_logging(BTRFS_I(inode),
&ctx.ordered_extents);
ret = filemap_fdatawait_range(inode->i_mapping, start, end);
}
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
if (ret)
goto out_release_extents;
atomic_inc(&root->log_batch);
Btrfs: kill trans_mutex We use trans_mutex for lots of things, here's a basic list 1) To serialize trans_handles joining the currently running transaction 2) To make sure that no new trans handles are started while we are committing 3) To protect the dead_roots list and the transaction lists Really the serializing trans_handles joining is not too hard, and can really get bogged down in acquiring a reference to the transaction. So replace the trans_mutex with a trans_lock spinlock and use it to do the following 1) Protect fs_info->running_transaction. All trans handles have to do is check this, and then take a reference of the transaction and keep on going. 2) Protect the fs_info->trans_list. This doesn't get used too much, basically it just holds the current transactions, which will usually just be the currently committing transaction and the currently running transaction at most. 3) Protect the dead roots list. This is only ever processed by splicing the list so this is relatively simple. 4) Protect the fs_info->reloc_ctl stuff. This is very lightweight and was using the trans_mutex before, so this is a pretty straightforward change. 5) Protect fs_info->no_trans_join. Because we don't hold the trans_lock over the entirety of the commit we need to have a way to block new people from creating a new transaction while we're doing our work. So we set no_trans_join and in join_transaction we test to see if that is set, and if it is we do a wait_on_commit. 6) Make the transaction use count atomic so we don't need to take locks to modify it when we're dropping references. 7) Add a commit_lock to the transaction to make sure multiple people trying to commit the same transaction don't race and commit at the same time. 8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl trans. I have tested this with xfstests, but obviously it is a pretty hairy change so lots of testing is greatly appreciated. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-12 05:25:13 +08:00
smp_mb();
btrfs: fix race leading to unpersisted data and metadata on fsync When doing a fast fsync on a file, there is a race which can result in the fsync returning success to user space without logging the inode and without durably persisting new data. The following example shows one possible scenario for this: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ touch /mnt/bar $ xfs_io -f -c "pwrite -S 0xab 0 1M" -c "fsync" /mnt/baz # Now we have: # file bar == inode 257 # file baz == inode 258 $ mv /mnt/baz /mnt/foo # Now we have: # file bar == inode 257 # file foo == inode 258 $ xfs_io -c "pwrite -S 0xcd 0 1M" /mnt/foo # fsync bar before foo, it is important to trigger the race. $ xfs_io -c "fsync" /mnt/bar $ xfs_io -c "fsync" /mnt/foo # After this: # inode 257, file bar, is empty # inode 258, file foo, has 1M filled with 0xcd <power failure> # Replay the log: $ mount /dev/sdc /mnt # After this point file foo should have 1M filled with 0xcd and not 0xab The following steps explain how the race happens: 1) Before the first fsync of inode 258, when it has the "baz" name, its ->logged_trans is 0, ->last_sub_trans is 0 and ->last_log_commit is -1. The inode also has the full sync flag set; 2) After the first fsync, we set inode 258 ->logged_trans to 6, which is the generation of the current transaction, and set ->last_log_commit to 0, which is the current value of ->last_sub_trans (done at btrfs_log_inode()). The full sync flag is cleared from the inode during the fsync. The log sub transaction that was committed had an ID of 0 and when we synced the log, at btrfs_sync_log(), we incremented root->log_transid from 0 to 1; 3) During the rename: We update inode 258, through btrfs_update_inode(), and that causes its ->last_sub_trans to be set to 1 (the current log transaction ID), and ->last_log_commit remains with a value of 0. After updating inode 258, because we have previously logged the inode in the previous fsync, we log again the inode through the call to btrfs_log_new_name(). This results in updating the inode's ->last_log_commit from 0 to 1 (the current value of its ->last_sub_trans). The ->last_sub_trans of inode 257 is updated to 1, which is the ID of the next log transaction; 4) Then a buffered write against inode 258 is made. This leaves the value of ->last_sub_trans as 1 (the ID of the current log transaction, stored at root->log_transid); 5) Then an fsync against inode 257 (or any other inode other than 258), happens. This results in committing the log transaction with ID 1, which results in updating root->last_log_commit to 1 and bumping root->log_transid from 1 to 2; 6) Then an fsync against inode 258 starts. We flush delalloc and wait only for writeback to complete, since the full sync flag is not set in the inode's runtime flags - we do not wait for ordered extents to complete. Then, at btrfs_sync_file(), we call btrfs_inode_in_log() before the ordered extent completes. The call returns true: static inline bool btrfs_inode_in_log(...) { bool ret = false; spin_lock(&inode->lock); if (inode->logged_trans == generation && inode->last_sub_trans <= inode->last_log_commit && inode->last_sub_trans <= inode->root->last_log_commit) ret = true; spin_unlock(&inode->lock); return ret; } generation has a value of 6 (fs_info->generation), ->logged_trans also has a value of 6 (set when we logged the inode during the first fsync and when logging it during the rename), ->last_sub_trans has a value of 1, set during the rename (step 3), ->last_log_commit also has a value of 1 (set in step 3) and root->last_log_commit has a value of 1, which was set in step 5 when fsyncing inode 257. As a consequence we don't log the inode, any new extents and do not sync the log, resulting in a data loss if a power failure happens after the fsync and before the current transaction commits. Also, because we do not log the inode, after a power failure the mtime and ctime of the inode do not match those we had before. When the ordered extent completes before we call btrfs_inode_in_log(), then the call returns false and we log the inode and sync the log, since at the end of ordered extent completion we update the inode and set ->last_sub_trans to 2 (the value of root->log_transid) and ->last_log_commit to 1. This problem is found after removing the check for the emptiness of the inode's list of modified extents in the recent commit 209ecbb8585bf6 ("btrfs: remove stale comment and logic from btrfs_inode_in_log()"), added in the 5.13 merge window. However checking the emptiness of the list is not really the way to solve this problem, and was never intended to, because while that solves the problem for COW writes, the problem persists for NOCOW writes because in that case the list is always empty. In the case of NOCOW writes, even though we wait for the writeback to complete before returning from btrfs_sync_file(), we end up not logging the inode, which has a new mtime/ctime, and because we don't sync the log, we never issue disk barriers (send REQ_PREFLUSH to the device) since that only happens when we sync the log (when we write super blocks at btrfs_sync_log()). So effectively, for a NOCOW case, when we return from btrfs_sync_file() to user space, we are not guaranteeing that the data is durably persisted on disk. Also, while the example above uses a rename exchange to show how the problem happens, it is not the only way to trigger it. An alternative could be adding a new hard link to inode 258, since that also results in calling btrfs_log_new_name() and updating the inode in the log. An example reproducer using the addition of a hard link instead of a rename operation: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ touch /mnt/bar $ xfs_io -f -c "pwrite -S 0xab 0 1M" -c "fsync" /mnt/foo $ ln /mnt/foo /mnt/foo_link $ xfs_io -c "pwrite -S 0xcd 0 1M" /mnt/foo $ xfs_io -c "fsync" /mnt/bar $ xfs_io -c "fsync" /mnt/foo <power failure> # Replay the log: $ mount /dev/sdc /mnt # After this point file foo often has 1M filled with 0xab and not 0xcd The reasons leading to the final fsync of file foo, inode 258, not persisting the new data are the same as for the previous example with a rename operation. So fix by never skipping logging and log syncing when there are still any ordered extents in flight. To avoid making the conditional if statement that checks if logging an inode is needed harder to read, place all the logic into an helper function with separate if statements to make it more manageable and easier to read. A test case for fstests will follow soon. For NOCOW writes, the problem existed before commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), introduced in kernel 4.19, then it went away with that commit since we started to always wait for ordered extent completion before logging. The problem came back again once the fast fsync path was changed again to avoid waiting for ordered extent completion, in commit 487781796d3022 ("btrfs: make fast fsyncs wait only for writeback"), added in kernel 5.10. However, for COW writes, the race only happens after the recent commit 209ecbb8585bf6 ("btrfs: remove stale comment and logic from btrfs_inode_in_log()"), introduced in the 5.13 merge window. For NOCOW writes, the bug existed before that commit. So tag 5.10+ as the release for stable backports. CC: stable@vger.kernel.org # 5.10+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-04-27 18:27:20 +08:00
if (skip_inode_logging(&ctx)) {
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
/*
* We've had everything committed since the last time we were
Btrfs: turbo charge fsync At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-08-18 01:14:17 +08:00
* modified so clear this flag in case it was set for whatever
* reason, it's no longer relevant.
*/
clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
/*
* An ordered extent might have started before and completed
* already with io errors, in which case the inode was not
* updated and we end up here. So check the inode's mapping
* for any errors that might have happened since we last
* checked called fsync.
*/
ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
goto out_release_extents;
}
/*
* We use start here because we will need to wait on the IO to complete
* in btrfs_sync_log, which could require joining a transaction (for
* example checking cross references in the nocow path). If we use join
* here we could get into a situation where we're waiting on IO to
* happen that is blocked on a transaction trying to commit. With start
* we inc the extwriter counter, so we wait for all extwriters to exit
* before we start blocking joiners. This comment is to keep somebody
* from thinking they are super smart and changing this to
* btrfs_join_transaction *cough*Josef*cough*.
*/
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
goto out_release_extents;
}
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit Often an fsync needs to fallback to a transaction commit for several reasons (to ensure consistency after a power failure, a new block group was allocated or a temporary error such as ENOMEM or ENOSPC happened). In that case the log is marked as needing a full commit and any concurrent tasks attempting to log inodes or commit the log will also fallback to the transaction commit. When this happens they all wait for the task that first started the transaction commit to finish the transaction commit - however they wait until the full transaction commit happens, which is not needed, as they only need to wait for the superblocks to be persisted and not for unpinning all the extents pinned during the transaction's lifetime, which even for short lived transactions can be a few thousand and take some significant amount of time to complete - for dbench workloads I have observed up to 4~5 milliseconds of time spent unpinning extents in the worst cases, and the number of pinned extents was between 2 to 3 thousand. So allow fsync tasks to skip waiting for the unpinning of extents when they call btrfs_commit_transaction() and they were not the task that started the transaction commit (that one has to do it, the alternative would be to offload the transaction commit to another task so that it could avoid waiting for the extent unpinning or offload the extent unpinning to another task). This patch is part of a patchset comprised of the following patches: btrfs: remove unnecessary directory inode item update when deleting dir entry btrfs: stop setting nbytes when filling inode item for logging btrfs: avoid logging new ancestor inodes when logging new inode btrfs: skip logging directories already logged when logging all parents btrfs: skip logging inodes already logged when logging new entries btrfs: remove unnecessary check_parent_dirs_for_sync() btrfs: make concurrent fsyncs wait less when waiting for a transaction commit After applying the entire patchset, dbench shows improvements in respect to throughput and latency. The script used to measure it is the following: $ cat dbench-test.sh #!/bin/bash DEV=/dev/sdk MNT=/mnt/sdk MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-m single -d single" echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor umount $DEV &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT dbench -D $MNT -t 300 64 umount $MNT The test was run on a physical machine with 12 cores (Intel corei7), 64G of ram, using a NVMe device and a non-debug kernel configuration (Debian's default configuration). Before applying patchset, 32 clients: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 9627107 0.153 61.938 Close 7072076 0.001 3.175 Rename 407633 1.222 44.439 Unlink 1943895 0.658 44.440 Deltree 256 17.339 110.891 Mkdir 128 0.003 0.009 Qpathinfo 8725406 0.064 17.850 Qfileinfo 1529516 0.001 2.188 Qfsinfo 1599884 0.002 1.457 Sfileinfo 784200 0.005 3.562 Find 3373513 0.411 30.312 WriteX 4802132 0.053 29.054 ReadX 15089959 0.002 5.801 LockX 31344 0.002 0.425 UnlockX 31344 0.001 0.173 Flush 674724 5.952 341.830 Throughput 1008.02 MB/sec 32 clients 32 procs max_latency=341.833 ms After applying patchset, 32 clients: After patchset, with 32 clients: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 9931568 0.111 25.597 Close 7295730 0.001 2.171 Rename 420549 0.982 49.714 Unlink 2005366 0.497 39.015 Deltree 256 11.149 89.242 Mkdir 128 0.002 0.014 Qpathinfo 9001863 0.049 20.761 Qfileinfo 1577730 0.001 2.546 Qfsinfo 1650508 0.002 3.531 Sfileinfo 809031 0.005 5.846 Find 3480259 0.309 23.977 WriteX 4952505 0.043 41.283 ReadX 15568127 0.002 5.476 LockX 32338 0.002 0.978 UnlockX 32338 0.001 2.032 Flush 696017 7.485 228.835 Throughput 1049.91 MB/sec 32 clients 32 procs max_latency=228.847 ms --> +4.1% throughput, -39.6% max latency Before applying patchset, 64 clients: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 8956748 0.342 108.312 Close 6579660 0.001 3.823 Rename 379209 2.396 81.897 Unlink 1808625 1.108 131.148 Deltree 256 25.632 172.176 Mkdir 128 0.003 0.018 Qpathinfo 8117615 0.131 55.916 Qfileinfo 1423495 0.001 2.635 Qfsinfo 1488496 0.002 5.412 Sfileinfo 729472 0.007 8.643 Find 3138598 0.855 78.321 WriteX 4470783 0.102 79.442 ReadX 14038139 0.002 7.578 LockX 29158 0.002 0.844 UnlockX 29158 0.001 0.567 Flush 627746 14.168 506.151 Throughput 924.738 MB/sec 64 clients 64 procs max_latency=506.154 ms After applying patchset, 64 clients: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 9069003 0.303 43.193 Close 6662328 0.001 3.888 Rename 383976 2.194 46.418 Unlink 1831080 1.022 43.873 Deltree 256 24.037 155.763 Mkdir 128 0.002 0.005 Qpathinfo 8219173 0.137 30.233 Qfileinfo 1441203 0.001 3.204 Qfsinfo 1507092 0.002 4.055 Sfileinfo 738775 0.006 5.431 Find 3177874 0.936 38.170 WriteX 4526152 0.084 39.518 ReadX 14213562 0.002 24.760 LockX 29522 0.002 1.221 UnlockX 29522 0.001 0.694 Flush 635652 14.358 422.039 Throughput 990.13 MB/sec 64 clients 64 procs max_latency=422.043 ms --> +6.8% throughput, -18.1% max latency Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-27 18:35:00 +08:00
trans->in_fsync = true;
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
ret = btrfs_log_dentry_safe(trans, dentry, &ctx);
btrfs_release_log_ctx_extents(&ctx);
if (ret < 0) {
/* Fallthrough and commit/free transaction. */
ret = 1;
}
/* we've logged all the items and now have a consistent
* version of the file in the log. It is possible that
* someone will come in and modify the file, but that's
* fine because the log is consistent on disk, and we
* have references to all of the file's extents
*
* It is possible that someone will come in and log the
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
btrfs: fix race between memory mapped writes and fsync When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush any new delalloc that might have been created before taking the lock and then wait either for the ordered extents to complete or just for the writeback to complete (depending on whether the full sync flag is set or not). We then start logging the inode and assume that while we are doing it no one else is touching the inode's file extent items (or adding new ones). That is generally true because all operations that modify an inode acquire the inode's lock first, including buffered and direct IO writes. However there is one exception: memory mapped writes, which do not and can not acquire the inode's lock. This can cause two types of issues: ending up logging file extent items with overlapping ranges, which is detected by the tree checker and will result in aborting the transaction when starting writeback for a log tree's extent buffers, or a silent corruption where we log a version of the file that never existed. Scenario 1 - logging overlapping extents The following steps explain how we can end up with file extents items with overlapping ranges in a log tree due to a race between a fsync and memory mapped writes: 1) Task A starts an fsync on inode X, which has the full sync runtime flag set. First it starts by flushing all delalloc for the inode; 2) Task A then locks the inode and flushes any other delalloc that might have been created after the previous flush and waits for all ordered extents to complete; 3) In the inode's root we have the following leaf: Leaf N, generation == current transaction id: --------------------------------------------------------- | (...) [ file extent item, offset 640K, length 128K ] | --------------------------------------------------------- The last file extent item in leaf N covers the file range from 640K to 768K; 4) Task B does a memory mapped write for the page corresponding to the file range from 764K to 768K; 5) Task A starts logging the inode. At copy_inode_items_to_log() it uses btrfs_search_forward() to search for leafs modified in the current transaction that contain items for the inode. It finds leaf N and copies all the inode items from that leaf into the log tree. Now the log tree has a copy of the last file extent item from leaf N. At the end of the while loop at copy_inode_items_to_log(), we have the minimum key set to: min_key.objectid = <inode X number> min_key.type = BTRFS_EXTENT_DATA_KEY min_key.offset = 640K Then we increment the key's offset by 1 so that the next call to btrfs_search_forward() leaves us at the first key greater than the key we just processed. But before btrfs_search_forward() is called again... 6) Dellaloc for the page at offset 764K, dirtied by task B, is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) When the respective ordered extent completes, it trims the length of the existing file extent item for file offset 640K from 128K to 124K, and a new file extent item is added with a key offset of 764K and a length of 4K; 8) Task A calls btrfs_search_forward(), which returns us a path pointing to the leaf (can be leaf N or some other) containing the new file extent item for file offset 764K. We end up copying this item to the log tree, which overlaps with the last copied file extent item, which covers the file range from 640K to 768K. When writeback is triggered for log tree's extent buffers, the issue will be detected by the tree checker which will dump a trace and an error message on dmesg/syslog. If the writeback is triggered when syncing the log, which typically is, then we also end up aborting the current transaction. This is the same type of problem fixed in 0c713cbab6200b ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"). Scenario 2 - logging a version of the file that never existed This scenario only happens when using the NO_HOLES feature and results in a silent corruption, in the sense that is not detectable by 'btrfs check' or the tree checker: 1) We have an inode I with a size of 1M and two file extent items, one covering an extent with disk_bytenr == X for the file range [0, 512K) and another one covering another extent with disk_bytenr == Y for the file range [512K, 1M); 2) A hole is punched for the file range [512K, 1M); 3) Task A starts an fsync of inode I, which has the full sync runtime flag set. It starts by flushing all existing delalloc, locks the inode (VFS lock), starts any new delalloc that might have been created before taking the lock and waits for all ordered extents to complete; 4) Some other task does a memory mapped write for the page corresponding to the file range [640K, 644K) for example; 5) Task A then logs all items of the inode with the call to copy_inode_items_to_log(); 6) In the meanwhile delalloc for the range [640K, 644K) is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) The ordered extent for the range [640K, 644K) completes and a file extent item for that range is added to the subvolume tree, pointing to a 4K extent with a disk_bytenr == Z; 8) Task A then calls btrfs_log_holes(), to scan for implicit holes in the subvolume tree. It finds two implicit holes: - one for the file range [512K, 640K) - one for the file range [644K, 1M) As a result we end up neither logging a hole for the range [640K, 644K) nor logging the file extent item with a disk_bytenr == Z. This means that if we have a power failure and replay the log tree we end up getting the following file extent layout: [ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M Which does not corresponding to any layout the file ever had before the power failure. The only two valid layouts would be: [ disk_bytenr X ] [ hole ] 0 512K 512K 1M and [ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M This can be fixed by serializing memory mapped writes with fsync, and there are two ways to do it: 1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX in the inode's io tree. This prevents the race but also blocks any reads during the duration of the fsync, which has a negative impact for many common workloads; 2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This semaphore was recently added by Josef's patch set: btrfs: add a i_mmap_lock to our inode btrfs: cleanup inode_lock/inode_unlock uses btrfs: exclude mmaps while doing remap btrfs: exclude mmap from happening during all fallocate operations and is used to solve races between memory mapped writes and clone/dedupe/fallocate. This also makes us have the same behaviour we have regarding other writes (buffered and direct IO) and fsync - block them while the inode logging is in progress. This change uses the second approach due to the performance impact of the first one. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-23 20:08:47 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
if (ret != BTRFS_NO_LOG_SYNC) {
if (!ret) {
ret = btrfs_sync_log(trans, root, &ctx);
if (!ret) {
ret = btrfs_end_transaction(trans);
goto out;
}
}
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
if (!full_sync) {
ret = btrfs_wait_ordered_range(inode, start, len);
if (ret) {
btrfs_end_transaction(trans);
goto out;
}
}
ret = btrfs_commit_transaction(trans);
} else {
ret = btrfs_end_transaction(trans);
}
out:
Btrfs: fix list_add corruption and soft lockups in fsync Xfstests btrfs/146 revealed this corruption, [ 58.138831] Buffer I/O error on dev dm-0, logical block 2621424, async page read [ 58.151233] BTRFS error (device sdf): bdev /dev/mapper/error-test errs: wr 1, rd 0, flush 0, corrupt 0, gen 0 [ 58.152403] list_add corruption. prev->next should be next (ffff88005e6775d8), but was ffffc9000189be88. (prev=ffffc9000189be88). [ 58.153518] ------------[ cut here ]------------ [ 58.153892] WARNING: CPU: 1 PID: 1287 at lib/list_debug.c:31 __list_add_valid+0x169/0x1f0 ... [ 58.157379] RIP: 0010:__list_add_valid+0x169/0x1f0 ... [ 58.161956] Call Trace: [ 58.162264] btrfs_log_inode_parent+0x5bd/0xfb0 [btrfs] [ 58.163583] btrfs_log_dentry_safe+0x60/0x80 [btrfs] [ 58.164003] btrfs_sync_file+0x4c2/0x6f0 [btrfs] [ 58.164393] vfs_fsync_range+0x5f/0xd0 [ 58.164898] do_fsync+0x5a/0x90 [ 58.165170] SyS_fsync+0x10/0x20 [ 58.165395] entry_SYSCALL_64_fastpath+0x1f/0xbe ... It turns out that we could record btrfs_log_ctx:io_err in log_one_extents when IO fails, but make log_one_extents() return '0' instead of -EIO, so the IO error is not acknowledged by the callers, i.e. btrfs_log_inode_parent(), which would remove btrfs_log_ctx:list from list head 'root->log_ctxs'. Since btrfs_log_ctx is allocated from stack memory, it'd get freed with a object alive on the list. then a future list_add will throw the above warning. This returns the correct error in the above case. Jeff also reported this while testing against his fsync error patch set[1]. [1]: https://www.spinics.net/lists/linux-btrfs/msg65308.html "btrfs list corruption and soft lockups while testing writeback error handling" Fixes: 8407f553268a4611f254 ("Btrfs: fix data corruption after fast fsync and writeback error") Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-22 05:35:40 +08:00
ASSERT(list_empty(&ctx.list));
err = file_check_and_advance_wb_err(file);
if (!ret)
ret = err;
return ret > 0 ? -EIO : ret;
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
out_release_extents:
btrfs_release_log_ctx_extents(&ctx);
btrfs: fix race between memory mapped writes and fsync When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush any new delalloc that might have been created before taking the lock and then wait either for the ordered extents to complete or just for the writeback to complete (depending on whether the full sync flag is set or not). We then start logging the inode and assume that while we are doing it no one else is touching the inode's file extent items (or adding new ones). That is generally true because all operations that modify an inode acquire the inode's lock first, including buffered and direct IO writes. However there is one exception: memory mapped writes, which do not and can not acquire the inode's lock. This can cause two types of issues: ending up logging file extent items with overlapping ranges, which is detected by the tree checker and will result in aborting the transaction when starting writeback for a log tree's extent buffers, or a silent corruption where we log a version of the file that never existed. Scenario 1 - logging overlapping extents The following steps explain how we can end up with file extents items with overlapping ranges in a log tree due to a race between a fsync and memory mapped writes: 1) Task A starts an fsync on inode X, which has the full sync runtime flag set. First it starts by flushing all delalloc for the inode; 2) Task A then locks the inode and flushes any other delalloc that might have been created after the previous flush and waits for all ordered extents to complete; 3) In the inode's root we have the following leaf: Leaf N, generation == current transaction id: --------------------------------------------------------- | (...) [ file extent item, offset 640K, length 128K ] | --------------------------------------------------------- The last file extent item in leaf N covers the file range from 640K to 768K; 4) Task B does a memory mapped write for the page corresponding to the file range from 764K to 768K; 5) Task A starts logging the inode. At copy_inode_items_to_log() it uses btrfs_search_forward() to search for leafs modified in the current transaction that contain items for the inode. It finds leaf N and copies all the inode items from that leaf into the log tree. Now the log tree has a copy of the last file extent item from leaf N. At the end of the while loop at copy_inode_items_to_log(), we have the minimum key set to: min_key.objectid = <inode X number> min_key.type = BTRFS_EXTENT_DATA_KEY min_key.offset = 640K Then we increment the key's offset by 1 so that the next call to btrfs_search_forward() leaves us at the first key greater than the key we just processed. But before btrfs_search_forward() is called again... 6) Dellaloc for the page at offset 764K, dirtied by task B, is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) When the respective ordered extent completes, it trims the length of the existing file extent item for file offset 640K from 128K to 124K, and a new file extent item is added with a key offset of 764K and a length of 4K; 8) Task A calls btrfs_search_forward(), which returns us a path pointing to the leaf (can be leaf N or some other) containing the new file extent item for file offset 764K. We end up copying this item to the log tree, which overlaps with the last copied file extent item, which covers the file range from 640K to 768K. When writeback is triggered for log tree's extent buffers, the issue will be detected by the tree checker which will dump a trace and an error message on dmesg/syslog. If the writeback is triggered when syncing the log, which typically is, then we also end up aborting the current transaction. This is the same type of problem fixed in 0c713cbab6200b ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"). Scenario 2 - logging a version of the file that never existed This scenario only happens when using the NO_HOLES feature and results in a silent corruption, in the sense that is not detectable by 'btrfs check' or the tree checker: 1) We have an inode I with a size of 1M and two file extent items, one covering an extent with disk_bytenr == X for the file range [0, 512K) and another one covering another extent with disk_bytenr == Y for the file range [512K, 1M); 2) A hole is punched for the file range [512K, 1M); 3) Task A starts an fsync of inode I, which has the full sync runtime flag set. It starts by flushing all existing delalloc, locks the inode (VFS lock), starts any new delalloc that might have been created before taking the lock and waits for all ordered extents to complete; 4) Some other task does a memory mapped write for the page corresponding to the file range [640K, 644K) for example; 5) Task A then logs all items of the inode with the call to copy_inode_items_to_log(); 6) In the meanwhile delalloc for the range [640K, 644K) is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) The ordered extent for the range [640K, 644K) completes and a file extent item for that range is added to the subvolume tree, pointing to a 4K extent with a disk_bytenr == Z; 8) Task A then calls btrfs_log_holes(), to scan for implicit holes in the subvolume tree. It finds two implicit holes: - one for the file range [512K, 640K) - one for the file range [644K, 1M) As a result we end up neither logging a hole for the range [640K, 644K) nor logging the file extent item with a disk_bytenr == Z. This means that if we have a power failure and replay the log tree we end up getting the following file extent layout: [ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M Which does not corresponding to any layout the file ever had before the power failure. The only two valid layouts would be: [ disk_bytenr X ] [ hole ] 0 512K 512K 1M and [ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M This can be fixed by serializing memory mapped writes with fsync, and there are two ways to do it: 1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX in the inode's io tree. This prevents the race but also blocks any reads during the duration of the fsync, which has a negative impact for many common workloads; 2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This semaphore was recently added by Josef's patch set: btrfs: add a i_mmap_lock to our inode btrfs: cleanup inode_lock/inode_unlock uses btrfs: exclude mmaps while doing remap btrfs: exclude mmap from happening during all fallocate operations and is used to solve races between memory mapped writes and clone/dedupe/fallocate. This also makes us have the same behaviour we have regarding other writes (buffered and direct IO) and fsync - block them while the inode logging is in progress. This change uses the second approach due to the performance impact of the first one. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-23 20:08:47 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
btrfs: make fast fsyncs wait only for writeback Currently regardless of a full or a fast fsync we always wait for ordered extents to complete, and then start logging the inode after that. However for fast fsyncs we can just wait for the writeback to complete, we don't need to wait for the ordered extents to complete since we use the list of modified extents maps to figure out which extents we must log and we can get their checksums directly from the ordered extents that are still in flight, otherwise look them up from the checksums tree. Until commit b5e6c3e170b770 ("btrfs: always wait on ordered extents at fsync time"), for fast fsyncs, we used to start logging without even waiting for the writeback to complete first, we would wait for it to complete after logging, while holding a transaction open, which lead to performance issues when using cgroups and probably for other cases too, as wait for IO while holding a transaction handle should be avoided as much as possible. After that, for fast fsyncs, we started to wait for ordered extents to complete before starting to log, which adds some latency to fsyncs and we even got at least one report about a performance drop which bisected to that particular change: https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/ This change makes fast fsyncs only wait for writeback to finish before starting to log the inode, instead of waiting for both the writeback to finish and for the ordered extents to complete. This brings back part of the logic we had that extracts checksums from in flight ordered extents, which are not yet in the checksums tree, and making sure transaction commits wait for the completion of ordered extents previously logged (by far most of the time they have already completed by the time a transaction commit starts, resulting in no wait at all), to avoid any data loss if an ordered extent completes after the transaction used to log an inode is committed, followed by a power failure. When there are no other tasks accessing the checksums and the subvolume btrees, the ordered extent completion is pretty fast, typically taking 100 to 200 microseconds only in my observations. However when there are other tasks accessing these btrees, ordered extent completion can take a lot more time due to lock contention on nodes and leaves of these btrees. I've seen cases over 2 milliseconds, which starts to be significant. In particular when we do have concurrent fsyncs against different files there is a lot of contention on the checksums btree, since we have many tasks writing the checksums into the btree and other tasks that already started the logging phase are doing lookups for checksums in the btree. This change also turns all ranged fsyncs into full ranged fsyncs, which is something we already did when not using the NO_HOLES features or when doing a full fsync. This is to guarantee we never miss checksums due to writeback having been triggered only for a part of an extent, and we end up logging the full extent but only checksums for the written range, which results in missing checksums after log replay. Allowing ranged fsyncs to operate again only in the original range, when using the NO_HOLES feature and doing a fast fsync is doable but requires some non trivial changes to the writeback path, which can always be worked on later if needed, but I don't think they are a very common use case. Several tests were performed using fio for different numbers of concurrent jobs, each writing and fsyncing its own file, for both sequential and random file writes. The tests were run on bare metal, no virtualization, on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device, with a kernel configuration that is the default of typical distributions (debian in this case), without debug options enabled (kasan, kmemleak, slub debug, debug of page allocations, lock debugging, etc). The following script that calls fio was used: $ cat test-fsync.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd -o space_cache=v2" MKFS_OPTIONS="-d single -m single" if [ $# -ne 5 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 BLOCK_SIZE=$4 WRITE_MODE=$5 if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'" exit 1 fi cat <<EOF > /tmp/fio-job.ini [writers] rw=$WRITE_MODE fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=$BLOCK_SIZE ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo echo "Using config:" echo cat /tmp/fio-job.ini echo umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The results were the following: ************************* *** sequential writes *** ************************* ==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec After patch: WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec (+9.8%, -8.8% runtime) ==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec After patch: WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec (+21.5% throughput, -17.8% runtime) ==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec After patch: WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec (+28.7% throughput, -22.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec After patch: WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec (+35.6% throughput, -25.2% runtime) ==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec After patch: WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec (+34.1% throughput, -25.6% runtime) ==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec After patch: WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec (+19.1% throughput, -16.4% runtime) ==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ==== Before patch: WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec After patch: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec (+23.1% throughput, -18.7% runtime) ************************ *** random writes *** ************************ ==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec After patch: WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec (+0.9% throughput, -1.7% runtime) ==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec After patch: WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec (+2.3% throughput, -2.0% runtime) ==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec After patch: WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec (+15.6% throughput, -13.3% runtime) ==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec After patch: WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec (+11.6% throughput, -10.7% runtime) ==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec After patch: WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec (+3.8% throughput, -3.8% runtime) ==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec After patch: WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec (+12.7% throughput, -11.2% runtime) ==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ==== Before patch: WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec After patch: WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec (+6.3% throughput, -6.0% runtime) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 19:43:58 +08:00
goto out;
}
static const struct vm_operations_struct btrfs_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = btrfs_page_mkwrite,
};
static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct address_space *mapping = filp->f_mapping;
if (!mapping->a_ops->readpage)
return -ENOEXEC;
file_accessed(filp);
vma->vm_ops = &btrfs_file_vm_ops;
return 0;
}
static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
int slot, u64 start, u64 end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != btrfs_ino(inode) ||
key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
return 0;
if (btrfs_file_extent_disk_bytenr(leaf, fi))
return 0;
if (key.offset == end)
return 1;
if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
return 1;
return 0;
}
static int fill_holes(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode,
struct btrfs_path *path, u64 offset, u64 end)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = inode->root;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct extent_map *hole_em;
struct extent_map_tree *em_tree = &inode->extent_tree;
struct btrfs_key key;
int ret;
if (btrfs_fs_incompat(fs_info, NO_HOLES))
goto out;
key.objectid = btrfs_ino(inode);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret <= 0) {
/*
* We should have dropped this offset, so if we find it then
* something has gone horribly wrong.
*/
if (ret == 0)
ret = -EINVAL;
return ret;
}
leaf = path->nodes[0];
if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
u64 num_bytes;
path->slots[0]--;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
end - offset;
btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, 0);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
u64 num_bytes;
key.offset = offset;
btrfs_set_item_key_safe(fs_info, path, &key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
offset;
btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, 0);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
btrfs_release_path(path);
ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode),
offset, 0, 0, end - offset, 0, end - offset, 0, 0, 0);
if (ret)
return ret;
out:
btrfs_release_path(path);
hole_em = alloc_extent_map();
if (!hole_em) {
btrfs_drop_extent_cache(inode, offset, end - 1, 0);
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
} else {
hole_em->start = offset;
hole_em->len = end - offset;
hole_em->ram_bytes = hole_em->len;
hole_em->orig_start = offset;
hole_em->block_start = EXTENT_MAP_HOLE;
hole_em->block_len = 0;
hole_em->orig_block_len = 0;
hole_em->compress_type = BTRFS_COMPRESS_NONE;
hole_em->generation = trans->transid;
do {
btrfs_drop_extent_cache(inode, offset, end - 1, 0);
write_lock(&em_tree->lock);
2013-04-06 04:51:15 +08:00
ret = add_extent_mapping(em_tree, hole_em, 1);
write_unlock(&em_tree->lock);
} while (ret == -EEXIST);
free_extent_map(hole_em);
if (ret)
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&inode->runtime_flags);
}
return 0;
}
/*
* Find a hole extent on given inode and change start/len to the end of hole
* extent.(hole/vacuum extent whose em->start <= start &&
* em->start + em->len > start)
* When a hole extent is found, return 1 and modify start/len.
*/
static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_map *em;
int ret = 0;
em = btrfs_get_extent(inode, NULL, 0,
Btrfs: fix invalid extent maps due to hole punching While punching a hole in a range that is not aligned with the sector size (currently the same as the page size) we can end up leaving an extent map in memory with a length that is smaller then the sector size or with a start offset that is not aligned to the sector size. Both cases are not expected and can lead to problems. This issue is easily detected after the patch from commit a7e3b975a0f9 ("Btrfs: fix reported number of inode blocks"), introduced in kernel 4.12-rc1, in a scenario like the following for example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -c "pwrite -S 0xaa -b 100K 0 100K" /mnt/foo $ xfs_io -c "fpunch 60K 90K" /mnt/foo $ xfs_io -c "pwrite -S 0xbb -b 100K 50K 100K" /mnt/foo $ xfs_io -c "pwrite -S 0xcc -b 50K 100K 50K" /mnt/foo $ umount /mnt After the unmount operation we can see several warnings emmitted due to underflows related to space reservation counters: [ 2837.443299] ------------[ cut here ]------------ [ 2837.447395] WARNING: CPU: 8 PID: 2474 at fs/btrfs/inode.c:9444 btrfs_destroy_inode+0xe8/0x27e [btrfs] [ 2837.452108] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button se rio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_gene ric raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy [ 2837.458389] CPU: 8 PID: 2474 Comm: umount Tainted: G W 4.10.0-rc8-btrfs-next-43+ #1 [ 2837.459754] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 2837.462379] Call Trace: [ 2837.462379] dump_stack+0x68/0x92 [ 2837.462379] __warn+0xc2/0xdd [ 2837.462379] warn_slowpath_null+0x1d/0x1f [ 2837.462379] btrfs_destroy_inode+0xe8/0x27e [btrfs] [ 2837.462379] destroy_inode+0x3d/0x55 [ 2837.462379] evict+0x177/0x17e [ 2837.462379] dispose_list+0x50/0x71 [ 2837.462379] evict_inodes+0x132/0x141 [ 2837.462379] generic_shutdown_super+0x3f/0xeb [ 2837.462379] kill_anon_super+0x12/0x1c [ 2837.462379] btrfs_kill_super+0x16/0x21 [btrfs] [ 2837.462379] deactivate_locked_super+0x30/0x68 [ 2837.462379] deactivate_super+0x36/0x39 [ 2837.462379] cleanup_mnt+0x58/0x76 [ 2837.462379] __cleanup_mnt+0x12/0x14 [ 2837.462379] task_work_run+0x77/0x9b [ 2837.462379] prepare_exit_to_usermode+0x9d/0xc5 [ 2837.462379] syscall_return_slowpath+0x196/0x1b9 [ 2837.462379] entry_SYSCALL_64_fastpath+0xab/0xad [ 2837.462379] RIP: 0033:0x7f3ef3e6b9a7 [ 2837.462379] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 2837.462379] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7 [ 2837.462379] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910 [ 2837.462379] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015 [ 2837.462379] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64 [ 2837.462379] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0 [ 2837.519355] ---[ end trace e79345fe24b30b8d ]--- [ 2837.596256] ------------[ cut here ]------------ [ 2837.597625] WARNING: CPU: 8 PID: 2474 at fs/btrfs/extent-tree.c:5699 btrfs_free_block_groups+0x246/0x3eb [btrfs] [ 2837.603547] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button serio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy [ 2837.659372] CPU: 8 PID: 2474 Comm: umount Tainted: G W 4.10.0-rc8-btrfs-next-43+ #1 [ 2837.663359] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 2837.663359] Call Trace: [ 2837.663359] dump_stack+0x68/0x92 [ 2837.663359] __warn+0xc2/0xdd [ 2837.663359] warn_slowpath_null+0x1d/0x1f [ 2837.663359] btrfs_free_block_groups+0x246/0x3eb [btrfs] [ 2837.663359] close_ctree+0x1dd/0x2e1 [btrfs] [ 2837.663359] ? evict_inodes+0x132/0x141 [ 2837.663359] btrfs_put_super+0x15/0x17 [btrfs] [ 2837.663359] generic_shutdown_super+0x6a/0xeb [ 2837.663359] kill_anon_super+0x12/0x1c [ 2837.663359] btrfs_kill_super+0x16/0x21 [btrfs] [ 2837.663359] deactivate_locked_super+0x30/0x68 [ 2837.663359] deactivate_super+0x36/0x39 [ 2837.663359] cleanup_mnt+0x58/0x76 [ 2837.663359] __cleanup_mnt+0x12/0x14 [ 2837.663359] task_work_run+0x77/0x9b [ 2837.663359] prepare_exit_to_usermode+0x9d/0xc5 [ 2837.663359] syscall_return_slowpath+0x196/0x1b9 [ 2837.663359] entry_SYSCALL_64_fastpath+0xab/0xad [ 2837.663359] RIP: 0033:0x7f3ef3e6b9a7 [ 2837.663359] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 2837.663359] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7 [ 2837.663359] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910 [ 2837.663359] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015 [ 2837.663359] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64 [ 2837.663359] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0 [ 2837.739445] ---[ end trace e79345fe24b30b8e ]--- [ 2837.745595] ------------[ cut here ]------------ [ 2837.746412] WARNING: CPU: 8 PID: 2474 at fs/btrfs/extent-tree.c:5700 btrfs_free_block_groups+0x261/0x3eb [btrfs] [ 2837.747955] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button serio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy [ 2837.755395] CPU: 8 PID: 2474 Comm: umount Tainted: G W 4.10.0-rc8-btrfs-next-43+ #1 [ 2837.756769] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 2837.758526] Call Trace: [ 2837.758925] dump_stack+0x68/0x92 [ 2837.759383] __warn+0xc2/0xdd [ 2837.759383] warn_slowpath_null+0x1d/0x1f [ 2837.759383] btrfs_free_block_groups+0x261/0x3eb [btrfs] [ 2837.759383] close_ctree+0x1dd/0x2e1 [btrfs] [ 2837.759383] ? evict_inodes+0x132/0x141 [ 2837.759383] btrfs_put_super+0x15/0x17 [btrfs] [ 2837.759383] generic_shutdown_super+0x6a/0xeb [ 2837.759383] kill_anon_super+0x12/0x1c [ 2837.759383] btrfs_kill_super+0x16/0x21 [btrfs] [ 2837.759383] deactivate_locked_super+0x30/0x68 [ 2837.759383] deactivate_super+0x36/0x39 [ 2837.759383] cleanup_mnt+0x58/0x76 [ 2837.759383] __cleanup_mnt+0x12/0x14 [ 2837.759383] task_work_run+0x77/0x9b [ 2837.759383] prepare_exit_to_usermode+0x9d/0xc5 [ 2837.759383] syscall_return_slowpath+0x196/0x1b9 [ 2837.759383] entry_SYSCALL_64_fastpath+0xab/0xad [ 2837.759383] RIP: 0033:0x7f3ef3e6b9a7 [ 2837.759383] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 2837.759383] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7 [ 2837.759383] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910 [ 2837.759383] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015 [ 2837.759383] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64 [ 2837.759383] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0 [ 2837.777063] ---[ end trace e79345fe24b30b8f ]--- [ 2837.778235] ------------[ cut here ]------------ [ 2837.778856] WARNING: CPU: 8 PID: 2474 at fs/btrfs/extent-tree.c:9825 btrfs_free_block_groups+0x348/0x3eb [btrfs] [ 2837.791385] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button serio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy [ 2837.797711] CPU: 8 PID: 2474 Comm: umount Tainted: G W 4.10.0-rc8-btrfs-next-43+ #1 [ 2837.798594] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 2837.800118] Call Trace: [ 2837.800515] dump_stack+0x68/0x92 [ 2837.801015] __warn+0xc2/0xdd [ 2837.801471] warn_slowpath_null+0x1d/0x1f [ 2837.801698] btrfs_free_block_groups+0x348/0x3eb [btrfs] [ 2837.801698] close_ctree+0x1dd/0x2e1 [btrfs] [ 2837.801698] ? evict_inodes+0x132/0x141 [ 2837.801698] btrfs_put_super+0x15/0x17 [btrfs] [ 2837.801698] generic_shutdown_super+0x6a/0xeb [ 2837.801698] kill_anon_super+0x12/0x1c [ 2837.801698] btrfs_kill_super+0x16/0x21 [btrfs] [ 2837.801698] deactivate_locked_super+0x30/0x68 [ 2837.801698] deactivate_super+0x36/0x39 [ 2837.801698] cleanup_mnt+0x58/0x76 [ 2837.801698] __cleanup_mnt+0x12/0x14 [ 2837.801698] task_work_run+0x77/0x9b [ 2837.801698] prepare_exit_to_usermode+0x9d/0xc5 [ 2837.801698] syscall_return_slowpath+0x196/0x1b9 [ 2837.801698] entry_SYSCALL_64_fastpath+0xab/0xad [ 2837.801698] RIP: 0033:0x7f3ef3e6b9a7 [ 2837.801698] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 2837.801698] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7 [ 2837.801698] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910 [ 2837.801698] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015 [ 2837.801698] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64 [ 2837.801698] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0 [ 2837.818441] ---[ end trace e79345fe24b30b90 ]--- [ 2837.818991] BTRFS info (device sdc): space_info 1 has 7974912 free, is not full [ 2837.819830] BTRFS info (device sdc): space_info total=8388608, used=417792, pinned=0, reserved=0, may_use=18446744073709547520, readonly=0 What happens in the above example is the following: 1) When punching the hole, at btrfs_punch_hole(), the variable tail_len is set to 2048 (as tail_start is 148Kb + 1 and offset + len is 150Kb). This results in the creation of an extent map with a length of 2Kb starting at file offset 148Kb, through find_first_non_hole() -> btrfs_get_extent(). 2) The second write (first write after the hole punch operation), sets the range [50Kb, 152Kb[ to delalloc. 3) The third write, at btrfs_find_new_delalloc_bytes(), sees the extent map covering the range [148Kb, 150Kb[ and ends up calling set_extent_bit() for the same range, which results in splitting an existing extent state record, covering the range [148Kb, 152Kb[ into two 2Kb extent state records, covering the ranges [148Kb, 150Kb[ and [150Kb, 152Kb[. 4) Finally at lock_and_cleanup_extent_if_need(), immediately after calling btrfs_find_new_delalloc_bytes() we clear the delalloc bit from the range [100Kb, 152Kb[ which results in the btrfs_clear_bit_hook() callback being invoked against the two 2Kb extent state records that cover the ranges [148Kb, 150Kb[ and [150Kb, 152Kb[. When called against the first 2Kb extent state, it calls btrfs_delalloc_release_metadata() with a length argument of 2048 bytes. That function rounds up the length to a sector size aligned length, so it ends up considering a length of 4096 bytes, and then calls calc_csum_metadata_size() which results in decrementing the inode's csum_bytes counter by 4096 bytes, so after it stays a value of 0 bytes. Then the same happens when btrfs_clear_bit_hook() is called against the second extent state that has a length of 2Kb, covering the range [150Kb, 152Kb[, the length is rounded up to 4096 and calc_csum_metadata_size() ends up being called to decrement 4096 bytes from the inode's csum_bytes counter, which at that time has a value of 0, leading to an underflow, which is exactly what triggers the first warning, at btrfs_destroy_inode(). All the other warnings relate to several space accounting counters that underflow as well due to similar reasons. A similar case but where the hole punching operation creates an extent map with a start offset not aligned to the sector size is the following: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "fpunch 695K 820K" $SCRATCH_MNT/bar $ xfs_io -c "pwrite -S 0xaa 1008K 307K" $SCRATCH_MNT/bar $ xfs_io -c "pwrite -S 0xbb -b 630K 1073K 630K" $SCRATCH_MNT/bar $ xfs_io -c "pwrite -S 0xcc -b 459K 1068K 459K" $SCRATCH_MNT/bar $ umount /mnt During the unmount operation we get similar traces for the same reasons as in the first example. So fix the hole punching operation to make sure it never creates extent maps with a length that is not aligned to the sector size nor with a start offset that is not aligned to the sector size, as this breaks all assumptions and it's a land mine. Fixes: d77815461f04 ("btrfs: Avoid trucating page or punching hole in a already existed hole.") Cc: <stable@vger.kernel.org> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-05-30 12:29:09 +08:00
round_down(*start, fs_info->sectorsize),
round_up(*len, fs_info->sectorsize));
if (IS_ERR(em))
return PTR_ERR(em);
/* Hole or vacuum extent(only exists in no-hole mode) */
if (em->block_start == EXTENT_MAP_HOLE) {
ret = 1;
*len = em->start + em->len > *start + *len ?
0 : *start + *len - em->start - em->len;
*start = em->start + em->len;
}
free_extent_map(em);
return ret;
}
static int btrfs_punch_hole_lock_range(struct inode *inode,
const u64 lockstart,
const u64 lockend,
struct extent_state **cached_state)
{
btrfs: fix the filemap_range_has_page() call in btrfs_punch_hole_lock_range() [BUG] With current subpage RW support, the following script can hang the fs with 64K page size. # mkfs.btrfs -f -s 4k $dev # mount $dev -o nospace_cache $mnt # fsstress -w -n 50 -p 1 -s 1607749395 -d $mnt The kernel will do an infinite loop in btrfs_punch_hole_lock_range(). [CAUSE] In btrfs_punch_hole_lock_range() we: - Truncate page cache range - Lock extent io tree - Wait any ordered extents in the range. We exit the loop until we meet all the following conditions: - No ordered extent in the lock range - No page is in the lock range The latter condition has a pitfall, it only works for sector size == PAGE_SIZE case. While can't handle the following subpage case: 0 32K 64K 96K 128K | |///////||//////| || lockstart=32K lockend=96K - 1 In this case, although the range crosses 2 pages, truncate_pagecache_range() will invalidate no page at all, but only zero the [32K, 96K) range of the two pages. Thus filemap_range_has_page(32K, 96K-1) will always return true, thus we will never meet the loop exit condition. [FIX] Fix the problem by doing page alignment for the lock range. Function filemap_range_has_page() has already handled lend < lstart case, we only need to round up @lockstart, and round_down @lockend for truncate_pagecache_range(). This modification should not change any thing for sector size == PAGE_SIZE case, as in that case our range is already page aligned. Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64] Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64] Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-05-31 16:50:54 +08:00
/*
* For subpage case, if the range is not at page boundary, we could
* have pages at the leading/tailing part of the range.
* This could lead to dead loop since filemap_range_has_page()
* will always return true.
* So here we need to do extra page alignment for
* filemap_range_has_page().
*/
const u64 page_lockstart = round_up(lockstart, PAGE_SIZE);
const u64 page_lockend = round_down(lockend + 1, PAGE_SIZE) - 1;
while (1) {
struct btrfs_ordered_extent *ordered;
int ret;
truncate_pagecache_range(inode, lockstart, lockend);
lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
cached_state);
ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode),
lockend);
/*
* We need to make sure we have no ordered extents in this range
* and nobody raced in and read a page in this range, if we did
* we need to try again.
*/
if ((!ordered ||
(ordered->file_offset + ordered->num_bytes <= lockstart ||
ordered->file_offset > lockend)) &&
!filemap_range_has_page(inode->i_mapping,
btrfs: fix the filemap_range_has_page() call in btrfs_punch_hole_lock_range() [BUG] With current subpage RW support, the following script can hang the fs with 64K page size. # mkfs.btrfs -f -s 4k $dev # mount $dev -o nospace_cache $mnt # fsstress -w -n 50 -p 1 -s 1607749395 -d $mnt The kernel will do an infinite loop in btrfs_punch_hole_lock_range(). [CAUSE] In btrfs_punch_hole_lock_range() we: - Truncate page cache range - Lock extent io tree - Wait any ordered extents in the range. We exit the loop until we meet all the following conditions: - No ordered extent in the lock range - No page is in the lock range The latter condition has a pitfall, it only works for sector size == PAGE_SIZE case. While can't handle the following subpage case: 0 32K 64K 96K 128K | |///////||//////| || lockstart=32K lockend=96K - 1 In this case, although the range crosses 2 pages, truncate_pagecache_range() will invalidate no page at all, but only zero the [32K, 96K) range of the two pages. Thus filemap_range_has_page(32K, 96K-1) will always return true, thus we will never meet the loop exit condition. [FIX] Fix the problem by doing page alignment for the lock range. Function filemap_range_has_page() has already handled lend < lstart case, we only need to round up @lockstart, and round_down @lockend for truncate_pagecache_range(). This modification should not change any thing for sector size == PAGE_SIZE case, as in that case our range is already page aligned. Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64] Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64] Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-05-31 16:50:54 +08:00
page_lockstart, page_lockend)) {
if (ordered)
btrfs_put_ordered_extent(ordered);
break;
}
if (ordered)
btrfs_put_ordered_extent(ordered);
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
lockend, cached_state);
ret = btrfs_wait_ordered_range(inode, lockstart,
lockend - lockstart + 1);
if (ret)
return ret;
}
return 0;
}
static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode,
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
struct btrfs_path *path,
struct btrfs_replace_extent_info *extent_info,
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
const u64 replace_len,
const u64 bytes_to_drop)
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = inode->root;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
struct btrfs_file_extent_item *extent;
struct extent_buffer *leaf;
struct btrfs_key key;
int slot;
struct btrfs_ref ref = { 0 };
int ret;
if (replace_len == 0)
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
return 0;
if (extent_info->disk_offset == 0 &&
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
btrfs_fs_incompat(fs_info, NO_HOLES)) {
btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
return 0;
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
}
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
key.objectid = btrfs_ino(inode);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = extent_info->file_offset;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
ret = btrfs_insert_empty_item(trans, root, path, &key,
sizeof(struct btrfs_file_extent_item));
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
if (ret)
return ret;
leaf = path->nodes[0];
slot = path->slots[0];
write_extent_buffer(leaf, extent_info->extent_buf,
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
btrfs_item_ptr_offset(leaf, slot),
sizeof(struct btrfs_file_extent_item));
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
if (extent_info->is_new_extent)
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
btrfs_set_file_extent_generation(leaf, extent, trans->transid);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
replace_len);
btrfs: use the file extent tree infrastructure We want to use this everywhere we modify the file extent items permanently. These include: 1) Inserting new file extents for writes and prealloc extents. 2) Truncating inode items. 3) btrfs_cont_expand(). 4) Insert inline extents. 5) Insert new extents from log replay. 6) Insert a new extent for clone, as it could be past i_size. 7) Hole punching For hole punching in particular it might seem it's not necessary because anybody extending would use btrfs_cont_expand, however there is a corner that still can give us trouble. Start with an empty file and fallocate KEEP_SIZE 1M-2M We now have a 0 length file, and a hole file extent from 0-1M, and a prealloc extent from 1M-2M. Now punch 1M-1.5M Because this is past i_size we have [HOLE EXTENT][ NOTHING ][PREALLOC] [0 1M][1M 1.5M][1.5M 2M] with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size to 1.5M, but our disk_i_size is still 0 until the ordered extent completes. However if we now immediately truncate 2M on the file we'll just call btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we commit the transaction here and crash we'll expose the gap. To fix this we need to clear the file extent mapping for the range that we punched but didn't insert a corresponding file extent for. This will mean the truncate will only get an disk_i_size set to 1M if we crash before the finish ordered io happens. I've written an xfstest to reproduce the problem and validate this fix. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 22:02:22 +08:00
if (ret)
return ret;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
/* If it's a hole, nothing more needs to be done. */
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
if (extent_info->disk_offset == 0) {
btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
return 0;
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
}
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop);
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
if (extent_info->is_new_extent && extent_info->insertions == 0) {
key.objectid = extent_info->disk_offset;
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = extent_info->disk_len;
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
ret = btrfs_alloc_reserved_file_extent(trans, root,
btrfs_ino(inode),
extent_info->file_offset,
extent_info->qgroup_reserved,
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
&key);
} else {
u64 ref_offset;
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
extent_info->disk_offset,
extent_info->disk_len, 0);
ref_offset = extent_info->file_offset - extent_info->data_offset;
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
btrfs_init_data_ref(&ref, root->root_key.objectid,
btrfs_ino(inode), ref_offset);
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
ret = btrfs_inc_extent_ref(trans, &ref);
}
extent_info->insertions++;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
return ret;
}
/*
* The respective range must have been previously locked, as well as the inode.
* The end offset is inclusive (last byte of the range).
* @extent_info is NULL for fallocate's hole punching and non-NULL when replacing
* the file range with an extent.
* When not punching a hole, we don't want to end up in a state where we dropped
* extents without inserting a new one, so we must abort the transaction to avoid
* a corruption.
*/
int btrfs_replace_file_extents(struct btrfs_inode *inode,
struct btrfs_path *path, const u64 start,
const u64 end,
struct btrfs_replace_extent_info *extent_info,
struct btrfs_trans_handle **trans_out)
{
struct btrfs_drop_extents_args drop_args = { 0 };
struct btrfs_root *root = inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1);
u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize);
struct btrfs_trans_handle *trans = NULL;
struct btrfs_block_rsv *rsv;
unsigned int rsv_count;
u64 cur_offset;
u64 len = end - start;
int ret = 0;
if (end <= start)
return -EINVAL;
rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
if (!rsv) {
ret = -ENOMEM;
goto out;
}
rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1);
rsv->failfast = 1;
/*
* 1 - update the inode
* 1 - removing the extents in the range
* 1 - adding the hole extent if no_holes isn't set or if we are
* replacing the range with a new extent
*/
if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info)
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
rsv_count = 3;
else
rsv_count = 2;
trans = btrfs_start_transaction(root, rsv_count);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
goto out_free;
}
ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
min_size, false);
BUG_ON(ret);
trans->block_rsv = rsv;
cur_offset = start;
drop_args.path = path;
drop_args.end = end + 1;
drop_args.drop_cache = true;
while (cur_offset < end) {
drop_args.start = cur_offset;
ret = btrfs_drop_extents(trans, root, inode, &drop_args);
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
/* If we are punching a hole decrement the inode's byte count */
if (!extent_info)
btrfs_update_inode_bytes(inode, 0,
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 19:07:34 +08:00
drop_args.bytes_found);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
if (ret != -ENOSPC) {
/*
* When cloning we want to avoid transaction aborts when
* nothing was done and we are attempting to clone parts
* of inline extents, in such cases -EOPNOTSUPP is
* returned by __btrfs_drop_extents() without having
* changed anything in the file.
*/
if (extent_info && !extent_info->is_new_extent &&
btrfs: fix metadata reservation for fallocate that leads to transaction aborts When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 18:27:20 +08:00
ret && ret != -EOPNOTSUPP)
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
btrfs_abort_transaction(trans, ret);
break;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
}
trans->block_rsv = &fs_info->trans_block_rsv;
if (!extent_info && cur_offset < drop_args.drop_end &&
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
cur_offset < ino_size) {
ret = fill_holes(trans, inode, path, cur_offset,
drop_args.drop_end);
if (ret) {
/*
* If we failed then we didn't insert our hole
* entries for the area we dropped, so now the
* fs is corrupted, so we must abort the
* transaction.
*/
btrfs_abort_transaction(trans, ret);
break;
}
} else if (!extent_info && cur_offset < drop_args.drop_end) {
btrfs: use the file extent tree infrastructure We want to use this everywhere we modify the file extent items permanently. These include: 1) Inserting new file extents for writes and prealloc extents. 2) Truncating inode items. 3) btrfs_cont_expand(). 4) Insert inline extents. 5) Insert new extents from log replay. 6) Insert a new extent for clone, as it could be past i_size. 7) Hole punching For hole punching in particular it might seem it's not necessary because anybody extending would use btrfs_cont_expand, however there is a corner that still can give us trouble. Start with an empty file and fallocate KEEP_SIZE 1M-2M We now have a 0 length file, and a hole file extent from 0-1M, and a prealloc extent from 1M-2M. Now punch 1M-1.5M Because this is past i_size we have [HOLE EXTENT][ NOTHING ][PREALLOC] [0 1M][1M 1.5M][1.5M 2M] with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size to 1.5M, but our disk_i_size is still 0 until the ordered extent completes. However if we now immediately truncate 2M on the file we'll just call btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we commit the transaction here and crash we'll expose the gap. To fix this we need to clear the file extent mapping for the range that we punched but didn't insert a corresponding file extent for. This will mean the truncate will only get an disk_i_size set to 1M if we crash before the finish ordered io happens. I've written an xfstest to reproduce the problem and validate this fix. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 22:02:22 +08:00
/*
* We are past the i_size here, but since we didn't
* insert holes we need to clear the mapped area so we
* know to not set disk_i_size in this area until a new
* file extent is inserted here.
*/
ret = btrfs_inode_clear_file_extent_range(inode,
cur_offset,
drop_args.drop_end - cur_offset);
btrfs: use the file extent tree infrastructure We want to use this everywhere we modify the file extent items permanently. These include: 1) Inserting new file extents for writes and prealloc extents. 2) Truncating inode items. 3) btrfs_cont_expand(). 4) Insert inline extents. 5) Insert new extents from log replay. 6) Insert a new extent for clone, as it could be past i_size. 7) Hole punching For hole punching in particular it might seem it's not necessary because anybody extending would use btrfs_cont_expand, however there is a corner that still can give us trouble. Start with an empty file and fallocate KEEP_SIZE 1M-2M We now have a 0 length file, and a hole file extent from 0-1M, and a prealloc extent from 1M-2M. Now punch 1M-1.5M Because this is past i_size we have [HOLE EXTENT][ NOTHING ][PREALLOC] [0 1M][1M 1.5M][1.5M 2M] with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size to 1.5M, but our disk_i_size is still 0 until the ordered extent completes. However if we now immediately truncate 2M on the file we'll just call btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we commit the transaction here and crash we'll expose the gap. To fix this we need to clear the file extent mapping for the range that we punched but didn't insert a corresponding file extent for. This will mean the truncate will only get an disk_i_size set to 1M if we crash before the finish ordered io happens. I've written an xfstest to reproduce the problem and validate this fix. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 22:02:22 +08:00
if (ret) {
/*
* We couldn't clear our area, so we could
* presumably adjust up and corrupt the fs, so
* we need to abort.
*/
btrfs_abort_transaction(trans, ret);
break;
}
}
if (extent_info &&
drop_args.drop_end > extent_info->file_offset) {
u64 replace_len = drop_args.drop_end -
extent_info->file_offset;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
ret = btrfs_insert_replace_extent(trans, inode, path,
extent_info, replace_len,
drop_args.bytes_found);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
extent_info->data_len -= replace_len;
extent_info->data_offset += replace_len;
extent_info->file_offset += replace_len;
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
}
ret = btrfs_update_inode(trans, root, inode);
if (ret)
break;
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(fs_info);
trans = btrfs_start_transaction(root, rsv_count);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
break;
}
ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
rsv, min_size, false);
BUG_ON(ret); /* shouldn't happen */
trans->block_rsv = rsv;
btrfs: fix a potential hole punching failure In commit d77815461f04 ("btrfs: Avoid trucating page or punching hole in a already existed hole."), existing holes can be skipped by calling find_first_non_hole() to adjust start and len. However, if the given len is invalid and large, when an EXTENT_MAP_HOLE extent is found, len will not be set to zero because (em->start + em->len) is less than (start + len). Then the ret will be 1 but len will not be set to 0. The propagated non-zero ret will result in fallocate failure. In the while-loop of btrfs_replace_file_extents(), len is not updated every time before it calls find_first_non_hole(). That is, after btrfs_drop_extents() successfully drops the last non-hole file extent, it may fail with ENOSPC when attempting to drop a file extent item representing a hole. The problem can happen. After it calls find_first_non_hole(), the cur_offset will be adjusted to be larger than or equal to end. However, since the len is not set to zero, the break-loop condition (ret && !len) will not be met. After it leaves the while-loop, fallocate will return 1, which is an unexpected return value. We're not able to construct a reproducible way to let btrfs_drop_extents() fail with ENOSPC after it drops the last non-hole file extent but with remaining holes left. However, it's quite easy to fix. We just need to update and check the len every time before we call find_first_non_hole(). To make the while loop more readable, we also pull the variable updates to the bottom of loop like this: while (cur_offset < end) { ... // update cur_offset & len // advance cur_offset & len in hole-punching case if needed } Reported-by: Robbie Ko <robbieko@synology.com> Fixes: d77815461f04 ("btrfs: Avoid trucating page or punching hole in a already existed hole.") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Robbie Ko <robbieko@synology.com> Reviewed-by: Chung-Chiang Cheng <cccheng@synology.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: BingJing Chang <bingjingc@synology.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-25 09:56:22 +08:00
cur_offset = drop_args.drop_end;
len = end - cur_offset;
if (!extent_info && len) {
ret = find_first_non_hole(inode, &cur_offset, &len);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
if (unlikely(ret < 0))
break;
if (ret && !len) {
ret = 0;
break;
}
}
}
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
/*
* If we were cloning, force the next fsync to be a full one since we
* we replaced (or just dropped in the case of cloning holes when
* NO_HOLES is enabled) file extent items and did not setup new extent
* maps for the replacement extents (or holes).
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
*/
if (extent_info && !extent_info->is_new_extent)
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
if (ret)
goto out_trans;
trans->block_rsv = &fs_info->trans_block_rsv;
/*
* If we are using the NO_HOLES feature we might have had already an
* hole that overlaps a part of the region [lockstart, lockend] and
* ends at (or beyond) lockend. Since we have no file extent items to
* represent holes, drop_end can be less than lockend and so we must
* make sure we have an extent map representing the existing hole (the
* call to __btrfs_drop_extents() might have dropped the existing extent
* map representing the existing hole), otherwise the fast fsync path
* will not record the existence of the hole region
* [existing_hole_start, lockend].
*/
if (drop_args.drop_end <= end)
drop_args.drop_end = end + 1;
/*
* Don't insert file hole extent item if it's for a range beyond eof
* (because it's useless) or if it represents a 0 bytes range (when
* cur_offset == drop_end).
*/
if (!extent_info && cur_offset < ino_size &&
cur_offset < drop_args.drop_end) {
ret = fill_holes(trans, inode, path, cur_offset,
drop_args.drop_end);
if (ret) {
/* Same comment as above. */
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
} else if (!extent_info && cur_offset < drop_args.drop_end) {
btrfs: use the file extent tree infrastructure We want to use this everywhere we modify the file extent items permanently. These include: 1) Inserting new file extents for writes and prealloc extents. 2) Truncating inode items. 3) btrfs_cont_expand(). 4) Insert inline extents. 5) Insert new extents from log replay. 6) Insert a new extent for clone, as it could be past i_size. 7) Hole punching For hole punching in particular it might seem it's not necessary because anybody extending would use btrfs_cont_expand, however there is a corner that still can give us trouble. Start with an empty file and fallocate KEEP_SIZE 1M-2M We now have a 0 length file, and a hole file extent from 0-1M, and a prealloc extent from 1M-2M. Now punch 1M-1.5M Because this is past i_size we have [HOLE EXTENT][ NOTHING ][PREALLOC] [0 1M][1M 1.5M][1.5M 2M] with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size to 1.5M, but our disk_i_size is still 0 until the ordered extent completes. However if we now immediately truncate 2M on the file we'll just call btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we commit the transaction here and crash we'll expose the gap. To fix this we need to clear the file extent mapping for the range that we punched but didn't insert a corresponding file extent for. This will mean the truncate will only get an disk_i_size set to 1M if we crash before the finish ordered io happens. I've written an xfstest to reproduce the problem and validate this fix. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 22:02:22 +08:00
/* See the comment in the loop above for the reasoning here. */
ret = btrfs_inode_clear_file_extent_range(inode, cur_offset,
drop_args.drop_end - cur_offset);
btrfs: use the file extent tree infrastructure We want to use this everywhere we modify the file extent items permanently. These include: 1) Inserting new file extents for writes and prealloc extents. 2) Truncating inode items. 3) btrfs_cont_expand(). 4) Insert inline extents. 5) Insert new extents from log replay. 6) Insert a new extent for clone, as it could be past i_size. 7) Hole punching For hole punching in particular it might seem it's not necessary because anybody extending would use btrfs_cont_expand, however there is a corner that still can give us trouble. Start with an empty file and fallocate KEEP_SIZE 1M-2M We now have a 0 length file, and a hole file extent from 0-1M, and a prealloc extent from 1M-2M. Now punch 1M-1.5M Because this is past i_size we have [HOLE EXTENT][ NOTHING ][PREALLOC] [0 1M][1M 1.5M][1.5M 2M] with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size to 1.5M, but our disk_i_size is still 0 until the ordered extent completes. However if we now immediately truncate 2M on the file we'll just call btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we commit the transaction here and crash we'll expose the gap. To fix this we need to clear the file extent mapping for the range that we punched but didn't insert a corresponding file extent for. This will mean the truncate will only get an disk_i_size set to 1M if we crash before the finish ordered io happens. I've written an xfstest to reproduce the problem and validate this fix. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 22:02:22 +08:00
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
}
if (extent_info) {
ret = btrfs_insert_replace_extent(trans, inode, path,
extent_info, extent_info->data_len,
drop_args.bytes_found);
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents When cloning extents (or deduplicating) we create a transaction with a space reservation that considers we will drop or update a single file extent item of the destination inode (that we modify a single leaf). That is fine for the vast majority of scenarios, however it might happen that we need to drop many file extent items, and adjust at most two file extent items, in the destination root, which can span multiple leafs. This will lead to either the call to btrfs_drop_extents() to fail with ENOSPC or the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode() (called through clone_finish_inode_update()) to fail with ENOSPC. Such failure results in a transaction abort, leaving the filesystem in a read-only mode. In order to fix this we need to follow the same approach as the hole punching code, where we create a local reservation with 1 unit and keep ending and starting transactions, after balancing the btree inode, when __btrfs_drop_extents() returns ENOSPC. So fix this by making the extent cloning call calls the recently added btrfs_punch_hole_range() helper, which is what does the mentioned work for hole punching, and make sure whenever we drop extent items in a transaction, we also add a replacing file extent item, to avoid corruption (a hole) if after ending a transaction and before starting a new one, the old transaction gets committed and a power failure happens before we finish cloning. A test case for fstests follows soon. Reported-by: David Goodwin <david@codepoets.co.uk> Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/ Reported-by: Sam Tygier <sam@tygier.co.uk> Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/ Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 18:09:50 +08:00
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
}
out_trans:
if (!trans)
goto out_free;
trans->block_rsv = &fs_info->trans_block_rsv;
if (ret)
btrfs_end_transaction(trans);
else
*trans_out = trans;
out_free:
btrfs_free_block_rsv(fs_info, rsv);
out:
return ret;
}
static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_state *cached_state = NULL;
struct btrfs_path *path;
struct btrfs_trans_handle *trans = NULL;
u64 lockstart;
u64 lockend;
u64 tail_start;
u64 tail_len;
u64 orig_start = offset;
int ret = 0;
bool same_block;
u64 ino_size;
bool truncated_block = false;
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
bool updated_inode = false;
ret = btrfs_wait_ordered_range(inode, offset, len);
if (ret)
return ret;
btrfs: exclude mmap from happening during all fallocate operations There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-11 06:14:36 +08:00
btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
ino_size = round_up(inode->i_size, fs_info->sectorsize);
ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
if (ret < 0)
goto out_only_mutex;
if (ret && !len) {
/* Already in a large hole */
ret = 0;
goto out_only_mutex;
}
lockstart = round_up(offset, btrfs_inode_sectorsize(BTRFS_I(inode)));
lockend = round_down(offset + len,
btrfs_inode_sectorsize(BTRFS_I(inode))) - 1;
same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
== (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
/*
* We needn't truncate any block which is beyond the end of the file
* because we are sure there is no data there.
*/
/*
* Only do this if we are in the same block and we aren't doing the
* entire block.
*/
if (same_block && len < fs_info->sectorsize) {
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
if (offset < ino_size) {
truncated_block = true;
ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
0);
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
} else {
ret = 0;
}
goto out_only_mutex;
}
/* zero back part of the first block */
2014-02-15 23:55:58 +08:00
if (offset < ino_size) {
truncated_block = true;
ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
if (ret) {
btrfs: exclude mmap from happening during all fallocate operations There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-11 06:14:36 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
return ret;
}
}
/* Check the aligned pages after the first unaligned page,
* if offset != orig_start, which means the first unaligned page
* including several following pages are already in holes,
* the extra check can be skipped */
if (offset == orig_start) {
/* after truncate page, check hole again */
len = offset + len - lockstart;
offset = lockstart;
ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
if (ret < 0)
goto out_only_mutex;
if (ret && !len) {
ret = 0;
goto out_only_mutex;
}
lockstart = offset;
}
/* Check the tail unaligned part is in a hole */
tail_start = lockend + 1;
tail_len = offset + len - tail_start;
if (tail_len) {
ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len);
if (unlikely(ret < 0))
goto out_only_mutex;
if (!ret) {
/* zero the front end of the last page */
if (tail_start + tail_len < ino_size) {
truncated_block = true;
ret = btrfs_truncate_block(BTRFS_I(inode),
tail_start + tail_len,
0, 1);
if (ret)
goto out_only_mutex;
btrfs: Use right extent length when inserting overlap extent map. When current btrfs finds that a new extent map is going to be insereted but failed with -EEXIST, it will try again to insert the extent map but with the length of sectorsize. This is OK if we don't enable 'no-holes' feature since all extent space is continuous, we will not go into the not found->insert routine. But if we enable 'no-holes' feature, it will make things out of control. e.g. in 4K sectorsize, we pass the following args to btrfs_get_extent(): btrfs_get_extent() args: start: 27874 len 4100 28672 27874 28672 27874+4100 32768 |-----------------------| |---------hole--------------------|---------data----------| 1) not found and insert Since no extent map containing the range, btrfs_get_extent() will go into the not_found and insert routine, which will try to insert the extent map (27874, 27847 + 4100). 2) first overlap But it overlaps with (28672, 32768) extent, so -EEXIST will be returned by add_extent_mapping(). 3) retry but still overlap After catching the -EEXIST, then btrfs_get_extent() will try insert it again but with 4K length, which still overlaps, so -EEXIST will be returned. This makes the following patch fail to punch hole. d77815461f047e561f77a07754ae923ade597d4e btrfs: Avoid trucating page or punching hole in a already existed hole. This patch will use the right length, which is the (exsisting->start - em->start) to insert, making the above patch works in 'no-holes' mode. Also, some small code style problems in above patch is fixed too. Reported-by: Filipe David Manana <fdmanana@gmail.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Filipe David Manana <fdmanana@suse.com> Tested-by: Filipe David Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-08-08 13:06:20 +08:00
}
}
}
if (lockend < lockstart) {
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
ret = 0;
goto out_only_mutex;
}
ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
&cached_state);
if (ret)
goto out_only_mutex;
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_replace_file_extents(BTRFS_I(inode), path, lockstart,
lockend, NULL, &trans);
btrfs_free_path(path);
if (ret)
goto out;
ASSERT(trans != NULL);
inode_inc_iversion(inode);
inode->i_mtime = inode->i_ctime = current_time(inode);
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
updated_inode = true;
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(fs_info);
out:
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
&cached_state);
out_only_mutex:
if (!updated_inode && truncated_block && !ret) {
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
/*
* If we only end up zeroing part of a page, we still need to
* update the inode item, so that all the time fields are
* updated as well as the necessary btrfs inode in memory fields
* for detecting, at fsync time, if the inode isn't yet in the
* log tree or it's there but not up to date.
*/
struct timespec64 now = current_time(inode);
inode_inc_iversion(inode);
inode->i_mtime = now;
inode->i_ctime = now;
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
} else {
int ret2;
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
ret2 = btrfs_end_transaction(trans);
if (!ret)
ret = ret2;
Btrfs: add missing inode update when punching hole When punching a file hole if we endup only zeroing parts of a page, because the start offset isn't a multiple of the sector size or the start offset and length fall within the same page, we were not updating the inode item. This prevented an fsync from doing anything, if no other file changes happened in the current transaction, because the fields in btrfs_inode used to check if the inode needs to be fsync'ed weren't updated. This issue is easy to reproduce and the following excerpt from the xfstest case I made shows how to trigger it: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file. $XFS_IO_PROG -f -c "pwrite -S 0x22 -b 16K 0 16K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, this makes btrfs update some btrfs inode specific fields # that are used to track if the inode needs to be written/updated to the fsync # log or not. After this fsync, the new values for those fields indicate that # a subsequent fsync does not need to touch the fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Force a commit of the current transaction. After this point, any operation # that modifies the data or metadata of our file, should update those fields in # the btrfs inode with values that make the next fsync operation write to the # fsync log. sync # Punch a hole in our file. This small range affects only 1 page. # This made the btrfs hole punching implementation write only some zeroes in # one page, but it did not update the btrfs inode fields used to determine if # the next fsync needs to write to the fsync log. $XFS_IO_PROG -c "fpunch 8000 4K" $SCRATCH_MNT/foo # Another variation of the previously mentioned case. $XFS_IO_PROG -c "fpunch 15000 100" $SCRATCH_MNT/foo # Now fsync the file. This was a no-operation because the previous hole punch # operation didn't update the inode's fields mentioned before, so they remained # with the values they had after the first fsync - that is, they indicate that # it is not needed to write to fsync log. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Enable writes and mount the fs. This makes the fsync log replay code run. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Because the last fsync didn't do anything, here the file content matched what # it was after the first fsync, before the holes were punched, and not what it # was after the holes were punched. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This issue has been around since 2012, when the punch hole implementation was added, commit 2aaa66558172 ("Btrfs: add hole punching"). A test case for xfstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-16 06:38:54 +08:00
}
}
btrfs: exclude mmap from happening during all fallocate operations There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-11 06:14:36 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
return ret;
}
/* Helper structure to record which range is already reserved */
struct falloc_range {
struct list_head list;
u64 start;
u64 len;
};
/*
* Helper function to add falloc range
*
* Caller should have locked the larger range of extent containing
* [start, len)
*/
static int add_falloc_range(struct list_head *head, u64 start, u64 len)
{
struct falloc_range *range = NULL;
if (!list_empty(head)) {
/*
* As fallocate iterates by bytenr order, we only need to check
* the last range.
*/
range = list_last_entry(head, struct falloc_range, list);
if (range->start + range->len == start) {
range->len += len;
return 0;
}
}
range = kmalloc(sizeof(*range), GFP_KERNEL);
if (!range)
return -ENOMEM;
range->start = start;
range->len = len;
list_add_tail(&range->list, head);
return 0;
}
static int btrfs_fallocate_update_isize(struct inode *inode,
const u64 end,
const int mode)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
int ret2;
if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
return 0;
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans))
return PTR_ERR(trans);
inode->i_ctime = current_time(inode);
i_size_write(inode, end);
btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
ret2 = btrfs_end_transaction(trans);
return ret ? ret : ret2;
}
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
enum {
RANGE_BOUNDARY_WRITTEN_EXTENT,
RANGE_BOUNDARY_PREALLOC_EXTENT,
RANGE_BOUNDARY_HOLE,
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
};
static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode,
u64 offset)
{
const u64 sectorsize = btrfs_inode_sectorsize(inode);
struct extent_map *em;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
int ret;
offset = round_down(offset, sectorsize);
em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize);
if (IS_ERR(em))
return PTR_ERR(em);
if (em->block_start == EXTENT_MAP_HOLE)
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
ret = RANGE_BOUNDARY_HOLE;
else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
else
ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
free_extent_map(em);
return ret;
}
static int btrfs_zero_range(struct inode *inode,
loff_t offset,
loff_t len,
const int mode)
{
struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
struct extent_map *em;
struct extent_changeset *data_reserved = NULL;
int ret;
u64 alloc_hint = 0;
const u64 sectorsize = btrfs_inode_sectorsize(BTRFS_I(inode));
u64 alloc_start = round_down(offset, sectorsize);
u64 alloc_end = round_up(offset + len, sectorsize);
u64 bytes_to_reserve = 0;
bool space_reserved = false;
inode_dio_wait(inode);
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
alloc_end - alloc_start);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
/*
* Avoid hole punching and extent allocation for some cases. More cases
* could be considered, but these are unlikely common and we keep things
* as simple as possible for now. Also, intentionally, if the target
* range contains one or more prealloc extents together with regular
* extents and holes, we drop all the existing extents and allocate a
* new prealloc extent, so that we get a larger contiguous disk extent.
*/
if (em->start <= alloc_start &&
test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
const u64 em_end = em->start + em->len;
if (em_end >= offset + len) {
/*
* The whole range is already a prealloc extent,
* do nothing except updating the inode's i_size if
* needed.
*/
free_extent_map(em);
ret = btrfs_fallocate_update_isize(inode, offset + len,
mode);
goto out;
}
/*
* Part of the range is already a prealloc extent, so operate
* only on the remaining part of the range.
*/
alloc_start = em_end;
ASSERT(IS_ALIGNED(alloc_start, sectorsize));
len = offset + len - alloc_start;
offset = alloc_start;
alloc_hint = em->block_start + em->len;
}
free_extent_map(em);
if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
sectorsize);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
free_extent_map(em);
ret = btrfs_fallocate_update_isize(inode, offset + len,
mode);
goto out;
}
if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
free_extent_map(em);
ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
0);
if (!ret)
ret = btrfs_fallocate_update_isize(inode,
offset + len,
mode);
return ret;
}
free_extent_map(em);
alloc_start = round_down(offset, sectorsize);
alloc_end = alloc_start + sectorsize;
goto reserve_space;
}
alloc_start = round_up(offset, sectorsize);
alloc_end = round_down(offset + len, sectorsize);
/*
* For unaligned ranges, check the pages at the boundaries, they might
* map to an extent, in which case we need to partially zero them, or
* they might map to a hole, in which case we need our allocation range
* to cover them.
*/
if (!IS_ALIGNED(offset, sectorsize)) {
ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
offset);
if (ret < 0)
goto out;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
if (ret == RANGE_BOUNDARY_HOLE) {
alloc_start = round_down(offset, sectorsize);
ret = 0;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
if (ret)
goto out;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
} else {
ret = 0;
}
}
if (!IS_ALIGNED(offset + len, sectorsize)) {
ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
offset + len);
if (ret < 0)
goto out;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
if (ret == RANGE_BOUNDARY_HOLE) {
alloc_end = round_up(offset + len, sectorsize);
ret = 0;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
ret = btrfs_truncate_block(BTRFS_I(inode), offset + len,
0, 1);
if (ret)
goto out;
Btrfs: fix space leak after fallocate and zero range operations If we do a buffered write after a zero range operation that has an unaligned (with the filesystem's sector size) end which also falls within an unwritten (prealloc) extent that is currently beyond the inode's i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE, we end up leaking data and metadata space. This happens because when zeroing a range we call btrfs_truncate_block(), which does delalloc (loads the page and partially zeroes its content), and in the buffered write path we only clear existing delalloc space reservation for the range we are writing into if that range starts at an offset smaller then the inode's i_size, which makes sense since we can not have delalloc extents beyond the i_size, only unwritten extents are allowed. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero -k 0 430K" /mnt/foobar $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar $ umount /mnt After the unmount we get the metadata and data space leaks reported in dmesg/syslog: [95794.602253] ------------[ cut here ]------------ [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs] [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.624188] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.625578] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.627647] Call Trace: [95794.628128] destroy_inode+0x3d/0x55 [95794.628573] evict+0x177/0x17e [95794.629010] dispose_list+0x50/0x71 [95794.629478] evict_inodes+0x132/0x141 [95794.630289] generic_shutdown_super+0x3f/0x10b [95794.630864] kill_anon_super+0x12/0x1c [95794.631383] btrfs_kill_super+0x16/0x21 [btrfs] [95794.631930] deactivate_locked_super+0x30/0x68 [95794.632539] deactivate_super+0x36/0x39 [95794.633200] cleanup_mnt+0x49/0x67 [95794.633818] __cleanup_mnt+0x12/0x14 [95794.634416] task_work_run+0x82/0xa6 [95794.634902] prepare_exit_to_usermode+0xe1/0x10c [95794.635525] syscall_return_slowpath+0x18c/0x1af [95794.636122] entry_SYSCALL_64_fastpath+0xab/0xad [95794.636834] RIP: 0033:0x7fa678cb99a7 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 [95794.646929] ---[ end trace e95877675c6ec007 ]--- [95794.647751] ------------[ cut here ]------------ [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs] [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.664342] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.665673] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.667629] Call Trace: [95794.668065] destroy_inode+0x3d/0x55 [95794.668637] evict+0x177/0x17e [95794.669179] dispose_list+0x50/0x71 [95794.669830] evict_inodes+0x132/0x141 [95794.670416] generic_shutdown_super+0x3f/0x10b [95794.671103] kill_anon_super+0x12/0x1c [95794.671786] btrfs_kill_super+0x16/0x21 [btrfs] [95794.672552] deactivate_locked_super+0x30/0x68 [95794.673393] deactivate_super+0x36/0x39 [95794.674107] cleanup_mnt+0x49/0x67 [95794.674706] __cleanup_mnt+0x12/0x14 [95794.675279] task_work_run+0x82/0xa6 [95794.675795] prepare_exit_to_usermode+0xe1/0x10c [95794.676507] syscall_return_slowpath+0x18c/0x1af [95794.677275] entry_SYSCALL_64_fastpath+0xab/0xad [95794.678006] RIP: 0033:0x7fa678cb99a7 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff [95794.687156] ---[ end trace e95877675c6ec008 ]--- [95794.687876] ------------[ cut here ]------------ [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs] [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0 [95794.705270] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.706341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.708030] Call Trace: [95794.708466] destroy_inode+0x3d/0x55 [95794.709071] evict+0x177/0x17e [95794.709497] dispose_list+0x50/0x71 [95794.709973] evict_inodes+0x132/0x141 [95794.710564] generic_shutdown_super+0x3f/0x10b [95794.711200] kill_anon_super+0x12/0x1c [95794.711633] btrfs_kill_super+0x16/0x21 [btrfs] [95794.712139] deactivate_locked_super+0x30/0x68 [95794.712608] deactivate_super+0x36/0x39 [95794.713093] cleanup_mnt+0x49/0x67 [95794.713514] __cleanup_mnt+0x12/0x14 [95794.713933] task_work_run+0x82/0xa6 [95794.714543] prepare_exit_to_usermode+0xe1/0x10c [95794.715247] syscall_return_slowpath+0x18c/0x1af [95794.715952] entry_SYSCALL_64_fastpath+0xab/0xad [95794.716653] RIP: 0033:0x7fa678cb99a7 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01 [95794.729203] ---[ end trace e95877675c6ec009 ]--- [95794.841054] ------------[ cut here ]------------ [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs] [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.863810] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.865149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.867198] Call Trace: [95794.867626] close_ctree+0x1db/0x2b8 [btrfs] [95794.868188] ? evict_inodes+0x132/0x141 [95794.869037] btrfs_put_super+0x15/0x17 [btrfs] [95794.870400] generic_shutdown_super+0x6a/0x10b [95794.871262] kill_anon_super+0x12/0x1c [95794.872046] btrfs_kill_super+0x16/0x21 [btrfs] [95794.872746] deactivate_locked_super+0x30/0x68 [95794.873687] deactivate_super+0x36/0x39 [95794.874639] cleanup_mnt+0x49/0x67 [95794.875504] __cleanup_mnt+0x12/0x14 [95794.876126] task_work_run+0x82/0xa6 [95794.876788] prepare_exit_to_usermode+0xe1/0x10c [95794.877777] syscall_return_slowpath+0x18c/0x1af [95794.878381] entry_SYSCALL_64_fastpath+0xab/0xad [95794.878888] RIP: 0033:0x7fa678cb99a7 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00 [95794.887980] ---[ end trace e95877675c6ec00a ]--- [95794.888739] ------------[ cut here ]------------ [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs] [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100 [95794.907459] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.908625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.910630] Call Trace: [95794.911153] close_ctree+0x1db/0x2b8 [btrfs] [95794.911837] ? evict_inodes+0x132/0x141 [95794.912344] btrfs_put_super+0x15/0x17 [btrfs] [95794.912975] generic_shutdown_super+0x6a/0x10b [95794.913788] kill_anon_super+0x12/0x1c [95794.914424] btrfs_kill_super+0x16/0x21 [btrfs] [95794.915142] deactivate_locked_super+0x30/0x68 [95794.915831] deactivate_super+0x36/0x39 [95794.916433] cleanup_mnt+0x49/0x67 [95794.917045] __cleanup_mnt+0x12/0x14 [95794.917665] task_work_run+0x82/0xa6 [95794.918309] prepare_exit_to_usermode+0xe1/0x10c [95794.919021] syscall_return_slowpath+0x18c/0x1af [95794.919722] entry_SYSCALL_64_fastpath+0xab/0xad [95794.920426] RIP: 0033:0x7fa678cb99a7 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00 [95794.930166] ---[ end trace e95877675c6ec00b ]--- [95794.930961] ------------[ cut here ]------------ [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100 [95794.949193] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.950495] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95794.952361] Call Trace: [95794.952811] close_ctree+0x1db/0x2b8 [btrfs] [95794.953522] ? evict_inodes+0x132/0x141 [95794.954543] btrfs_put_super+0x15/0x17 [btrfs] [95794.955231] generic_shutdown_super+0x6a/0x10b [95794.955916] kill_anon_super+0x12/0x1c [95794.956414] btrfs_kill_super+0x16/0x21 [btrfs] [95794.956953] deactivate_locked_super+0x30/0x68 [95794.957635] deactivate_super+0x36/0x39 [95794.958256] cleanup_mnt+0x49/0x67 [95794.958701] __cleanup_mnt+0x12/0x14 [95794.959181] task_work_run+0x82/0xa6 [95794.959635] prepare_exit_to_usermode+0xe1/0x10c [95794.960182] syscall_return_slowpath+0x18c/0x1af [95794.960731] entry_SYSCALL_64_fastpath+0xab/0xad [95794.961438] RIP: 0033:0x7fa678cb99a7 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95794.970629] ---[ end trace e95877675c6ec00c ]--- [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0 [95794.973595] ------------[ cut here ]------------ [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs] [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G W 4.14.0-rc6-btrfs-next-54+ #1 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs] [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000 [95794.997233] FS: 00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [95794.998592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0 [95795.000542] Call Trace: [95795.001138] close_ctree+0x1db/0x2b8 [btrfs] [95795.001885] ? evict_inodes+0x132/0x141 [95795.002407] btrfs_put_super+0x15/0x17 [btrfs] [95795.003093] generic_shutdown_super+0x6a/0x10b [95795.003720] kill_anon_super+0x12/0x1c [95795.004353] btrfs_kill_super+0x16/0x21 [btrfs] [95795.005095] deactivate_locked_super+0x30/0x68 [95795.005716] deactivate_super+0x36/0x39 [95795.006388] cleanup_mnt+0x49/0x67 [95795.006939] __cleanup_mnt+0x12/0x14 [95795.007512] task_work_run+0x82/0xa6 [95795.008124] prepare_exit_to_usermode+0xe1/0x10c [95795.008994] syscall_return_slowpath+0x18c/0x1af [95795.009831] entry_SYSCALL_64_fastpath+0xab/0xad [95795.010610] RIP: 0033:0x7fa678cb99a7 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff [95795.020538] ---[ end trace e95877675c6ec00d ]--- [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536 Fix this by ensuring the zero range operation does not call btrfs_truncate_block() if the corresponding extent is an unwritten one (it's pointless anyway, since reading from an unwritten extent yields zeroes). Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-18 19:34:31 +08:00
} else {
ret = 0;
}
}
reserve_space:
if (alloc_start < alloc_end) {
struct extent_state *cached_state = NULL;
const u64 lockstart = alloc_start;
const u64 lockend = alloc_end - 1;
bytes_to_reserve = alloc_end - alloc_start;
ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
bytes_to_reserve);
if (ret < 0)
goto out;
space_reserved = true;
ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
&cached_state);
if (ret)
goto out;
ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved,
alloc_start, bytes_to_reserve);
if (ret) {
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
lockend, &cached_state);
goto out;
}
ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
alloc_end - alloc_start,
i_blocksize(inode),
offset + len, &alloc_hint);
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
lockend, &cached_state);
/* btrfs_prealloc_file_range releases reserved space on error */
if (ret) {
space_reserved = false;
goto out;
}
}
ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
out:
if (ret && space_reserved)
btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
alloc_start, bytes_to_reserve);
extent_changeset_free(data_reserved);
return ret;
}
static long btrfs_fallocate(struct file *file, int mode,
loff_t offset, loff_t len)
{
struct inode *inode = file_inode(file);
struct extent_state *cached_state = NULL;
struct extent_changeset *data_reserved = NULL;
struct falloc_range *range;
struct falloc_range *tmp;
struct list_head reserve_list;
u64 cur_offset;
u64 last_byte;
u64 alloc_start;
u64 alloc_end;
u64 alloc_hint = 0;
u64 locked_end;
u64 actual_end = 0;
struct extent_map *em;
int blocksize = btrfs_inode_sectorsize(BTRFS_I(inode));
int ret;
/* Do not allow fallocate in ZONED mode */
if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
return -EOPNOTSUPP;
alloc_start = round_down(offset, blocksize);
alloc_end = round_up(offset + len, blocksize);
btrfs: update btrfs_space_info's bytes_may_use timely This patch can fix some false ENOSPC errors, below test script can reproduce one false ENOSPC error: #!/bin/bash dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 dev=$(losetup --show -f fs.img) mkfs.btrfs -f -M $dev mkdir /tmp/mntpoint mount $dev /tmp/mntpoint cd /tmp/mntpoint xfs_io -f -c "falloc 0 $((64*1024*1024))" testfile Above script will fail for ENOSPC reason, but indeed fs still has free space to satisfy this request. Please see call graph: btrfs_fallocate() |-> btrfs_alloc_data_chunk_ondemand() | bytes_may_use += 64M |-> btrfs_prealloc_file_range() |-> btrfs_reserve_extent() |-> btrfs_add_reserved_bytes() | alloc_type is RESERVE_ALLOC_NO_ACCOUNT, so it does not | change bytes_may_use, and bytes_reserved += 64M. Now | bytes_may_use + bytes_reserved == 128M, which is greater | than btrfs_space_info's total_bytes, false enospc occurs. | Note, the bytes_may_use decrease operation will be done in | end of btrfs_fallocate(), which is too late. Here is another simple case for buffered write: CPU 1 | CPU 2 | |-> cow_file_range() |-> __btrfs_buffered_write() |-> btrfs_reserve_extent() | | | | | | | | | ..... | |-> btrfs_check_data_free_space() | | | | |-> extent_clear_unlock_delalloc() | In CPU 1, btrfs_reserve_extent()->find_free_extent()-> btrfs_add_reserved_bytes() do not decrease bytes_may_use, the decrease operation will be delayed to be done in extent_clear_unlock_delalloc(). Assume in this case, btrfs_reserve_extent() reserved 128MB data, CPU2's btrfs_check_data_free_space() tries to reserve 100MB data space. If 100MB > data_sinfo->total_bytes - data_sinfo->bytes_used - data_sinfo->bytes_reserved - data_sinfo->bytes_pinned - data_sinfo->bytes_readonly - data_sinfo->bytes_may_use btrfs_check_data_free_space() will try to allcate new data chunk or call btrfs_start_delalloc_roots(), or commit current transaction in order to reserve some free space, obviously a lot of work. But indeed it's not necessary as long as decreasing bytes_may_use timely, we still have free space, decreasing 128M from bytes_may_use. To fix this issue, this patch chooses to update bytes_may_use for both data and metadata in btrfs_add_reserved_bytes(). For compress path, real extent length may not be equal to file content length, so introduce a ram_bytes argument for btrfs_reserve_extent(), find_free_extent() and btrfs_add_reserved_bytes(), it's becasue bytes_may_use is increased by file content length. Then compress path can update bytes_may_use correctly. Also now we can discard RESERVE_ALLOC_NO_ACCOUNT, RESERVE_ALLOC and RESERVE_FREE. As we know, usually EXTENT_DO_ACCOUNTING is used for error path. In run_delalloc_nocow(), for inode marked as NODATACOW or extent marked as PREALLOC, we also need to update bytes_may_use, but can not pass EXTENT_DO_ACCOUNTING, because it also clears metadata reservation, so here we introduce EXTENT_CLEAR_DATA_RESV flag to indicate btrfs_clear_bit_hook() to update btrfs_space_info's bytes_may_use. Meanwhile __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() internally for both sucessful and failed path, btrfs_prealloc_file_range()'s callers does not need to call btrfs_free_reserved_data_space() any more. Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2016-07-25 15:51:40 +08:00
cur_offset = alloc_start;
/* Make sure we aren't being give some crap mode */
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
FALLOC_FL_ZERO_RANGE))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
return btrfs_punch_hole(inode, offset, len);
/*
* Only trigger disk allocation, don't trigger qgroup reserve
*
* For qgroup space, it will be checked later.
*/
if (!(mode & FALLOC_FL_ZERO_RANGE)) {
ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
alloc_end - alloc_start);
if (ret < 0)
return ret;
}
btrfs: exclude mmap from happening during all fallocate operations There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-11 06:14:36 +08:00
btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
ret = inode_newsize_ok(inode, offset + len);
if (ret)
goto out;
}
/*
* TODO: Move these two operations after we have checked
* accurate reserved space, or fallocate can still fail but
* with page truncated or size expanded.
*
* But that's a minor problem and won't do much harm BTW.
*/
if (alloc_start > inode->i_size) {
ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode),
alloc_start);
if (ret)
goto out;
} else if (offset + len > inode->i_size) {
/*
* If we are fallocating from the end of the file onward we
* need to zero out the end of the block if i_size lands in the
* middle of a block.
*/
ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0);
if (ret)
goto out;
}
/*
* wait for ordered IO before we have any locks. We'll loop again
* below with the locks held.
*/
ret = btrfs_wait_ordered_range(inode, alloc_start,
alloc_end - alloc_start);
if (ret)
goto out;
if (mode & FALLOC_FL_ZERO_RANGE) {
ret = btrfs_zero_range(inode, offset, len, mode);
btrfs: exclude mmap from happening during all fallocate operations There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-11 06:14:36 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
return ret;
}
locked_end = alloc_end - 1;
while (1) {
struct btrfs_ordered_extent *ordered;
/* the extent lock is ordered inside the running
* transaction
*/
lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
locked_end, &cached_state);
ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode),
locked_end);
if (ordered &&
ordered->file_offset + ordered->num_bytes > alloc_start &&
ordered->file_offset < alloc_end) {
btrfs_put_ordered_extent(ordered);
unlock_extent_cached(&BTRFS_I(inode)->io_tree,
alloc_start, locked_end,
&cached_state);
/*
* we can't wait on the range with the transaction
* running or with the extent lock held
*/
ret = btrfs_wait_ordered_range(inode, alloc_start,
alloc_end - alloc_start);
if (ret)
goto out;
} else {
if (ordered)
btrfs_put_ordered_extent(ordered);
break;
}
}
/* First, check if we exceed the qgroup limit */
INIT_LIST_HEAD(&reserve_list);
while (cur_offset < alloc_end) {
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
alloc_end - cur_offset);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
break;
}
last_byte = min(extent_map_end(em), alloc_end);
actual_end = min_t(u64, extent_map_end(em), offset + len);
last_byte = ALIGN(last_byte, blocksize);
if (em->block_start == EXTENT_MAP_HOLE ||
(cur_offset >= inode->i_size &&
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
ret = add_falloc_range(&reserve_list, cur_offset,
last_byte - cur_offset);
if (ret < 0) {
free_extent_map(em);
break;
}
ret = btrfs_qgroup_reserve_data(BTRFS_I(inode),
&data_reserved, cur_offset,
last_byte - cur_offset);
if (ret < 0) {
cur_offset = last_byte;
free_extent_map(em);
break;
}
btrfs: update btrfs_space_info's bytes_may_use timely This patch can fix some false ENOSPC errors, below test script can reproduce one false ENOSPC error: #!/bin/bash dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 dev=$(losetup --show -f fs.img) mkfs.btrfs -f -M $dev mkdir /tmp/mntpoint mount $dev /tmp/mntpoint cd /tmp/mntpoint xfs_io -f -c "falloc 0 $((64*1024*1024))" testfile Above script will fail for ENOSPC reason, but indeed fs still has free space to satisfy this request. Please see call graph: btrfs_fallocate() |-> btrfs_alloc_data_chunk_ondemand() | bytes_may_use += 64M |-> btrfs_prealloc_file_range() |-> btrfs_reserve_extent() |-> btrfs_add_reserved_bytes() | alloc_type is RESERVE_ALLOC_NO_ACCOUNT, so it does not | change bytes_may_use, and bytes_reserved += 64M. Now | bytes_may_use + bytes_reserved == 128M, which is greater | than btrfs_space_info's total_bytes, false enospc occurs. | Note, the bytes_may_use decrease operation will be done in | end of btrfs_fallocate(), which is too late. Here is another simple case for buffered write: CPU 1 | CPU 2 | |-> cow_file_range() |-> __btrfs_buffered_write() |-> btrfs_reserve_extent() | | | | | | | | | ..... | |-> btrfs_check_data_free_space() | | | | |-> extent_clear_unlock_delalloc() | In CPU 1, btrfs_reserve_extent()->find_free_extent()-> btrfs_add_reserved_bytes() do not decrease bytes_may_use, the decrease operation will be delayed to be done in extent_clear_unlock_delalloc(). Assume in this case, btrfs_reserve_extent() reserved 128MB data, CPU2's btrfs_check_data_free_space() tries to reserve 100MB data space. If 100MB > data_sinfo->total_bytes - data_sinfo->bytes_used - data_sinfo->bytes_reserved - data_sinfo->bytes_pinned - data_sinfo->bytes_readonly - data_sinfo->bytes_may_use btrfs_check_data_free_space() will try to allcate new data chunk or call btrfs_start_delalloc_roots(), or commit current transaction in order to reserve some free space, obviously a lot of work. But indeed it's not necessary as long as decreasing bytes_may_use timely, we still have free space, decreasing 128M from bytes_may_use. To fix this issue, this patch chooses to update bytes_may_use for both data and metadata in btrfs_add_reserved_bytes(). For compress path, real extent length may not be equal to file content length, so introduce a ram_bytes argument for btrfs_reserve_extent(), find_free_extent() and btrfs_add_reserved_bytes(), it's becasue bytes_may_use is increased by file content length. Then compress path can update bytes_may_use correctly. Also now we can discard RESERVE_ALLOC_NO_ACCOUNT, RESERVE_ALLOC and RESERVE_FREE. As we know, usually EXTENT_DO_ACCOUNTING is used for error path. In run_delalloc_nocow(), for inode marked as NODATACOW or extent marked as PREALLOC, we also need to update bytes_may_use, but can not pass EXTENT_DO_ACCOUNTING, because it also clears metadata reservation, so here we introduce EXTENT_CLEAR_DATA_RESV flag to indicate btrfs_clear_bit_hook() to update btrfs_space_info's bytes_may_use. Meanwhile __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() internally for both sucessful and failed path, btrfs_prealloc_file_range()'s callers does not need to call btrfs_free_reserved_data_space() any more. Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2016-07-25 15:51:40 +08:00
} else {
/*
* Do not need to reserve unwritten extent for this
* range, free reserved data space first, otherwise
* it'll result in false ENOSPC error.
*/
btrfs_free_reserved_data_space(BTRFS_I(inode),
data_reserved, cur_offset,
last_byte - cur_offset);
}
free_extent_map(em);
cur_offset = last_byte;
}
/*
* If ret is still 0, means we're OK to fallocate.
* Or just cleanup the list and exit.
*/
list_for_each_entry_safe(range, tmp, &reserve_list, list) {
if (!ret)
ret = btrfs_prealloc_file_range(inode, mode,
range->start,
range->len, i_blocksize(inode),
offset + len, &alloc_hint);
btrfs: update btrfs_space_info's bytes_may_use timely This patch can fix some false ENOSPC errors, below test script can reproduce one false ENOSPC error: #!/bin/bash dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 dev=$(losetup --show -f fs.img) mkfs.btrfs -f -M $dev mkdir /tmp/mntpoint mount $dev /tmp/mntpoint cd /tmp/mntpoint xfs_io -f -c "falloc 0 $((64*1024*1024))" testfile Above script will fail for ENOSPC reason, but indeed fs still has free space to satisfy this request. Please see call graph: btrfs_fallocate() |-> btrfs_alloc_data_chunk_ondemand() | bytes_may_use += 64M |-> btrfs_prealloc_file_range() |-> btrfs_reserve_extent() |-> btrfs_add_reserved_bytes() | alloc_type is RESERVE_ALLOC_NO_ACCOUNT, so it does not | change bytes_may_use, and bytes_reserved += 64M. Now | bytes_may_use + bytes_reserved == 128M, which is greater | than btrfs_space_info's total_bytes, false enospc occurs. | Note, the bytes_may_use decrease operation will be done in | end of btrfs_fallocate(), which is too late. Here is another simple case for buffered write: CPU 1 | CPU 2 | |-> cow_file_range() |-> __btrfs_buffered_write() |-> btrfs_reserve_extent() | | | | | | | | | ..... | |-> btrfs_check_data_free_space() | | | | |-> extent_clear_unlock_delalloc() | In CPU 1, btrfs_reserve_extent()->find_free_extent()-> btrfs_add_reserved_bytes() do not decrease bytes_may_use, the decrease operation will be delayed to be done in extent_clear_unlock_delalloc(). Assume in this case, btrfs_reserve_extent() reserved 128MB data, CPU2's btrfs_check_data_free_space() tries to reserve 100MB data space. If 100MB > data_sinfo->total_bytes - data_sinfo->bytes_used - data_sinfo->bytes_reserved - data_sinfo->bytes_pinned - data_sinfo->bytes_readonly - data_sinfo->bytes_may_use btrfs_check_data_free_space() will try to allcate new data chunk or call btrfs_start_delalloc_roots(), or commit current transaction in order to reserve some free space, obviously a lot of work. But indeed it's not necessary as long as decreasing bytes_may_use timely, we still have free space, decreasing 128M from bytes_may_use. To fix this issue, this patch chooses to update bytes_may_use for both data and metadata in btrfs_add_reserved_bytes(). For compress path, real extent length may not be equal to file content length, so introduce a ram_bytes argument for btrfs_reserve_extent(), find_free_extent() and btrfs_add_reserved_bytes(), it's becasue bytes_may_use is increased by file content length. Then compress path can update bytes_may_use correctly. Also now we can discard RESERVE_ALLOC_NO_ACCOUNT, RESERVE_ALLOC and RESERVE_FREE. As we know, usually EXTENT_DO_ACCOUNTING is used for error path. In run_delalloc_nocow(), for inode marked as NODATACOW or extent marked as PREALLOC, we also need to update bytes_may_use, but can not pass EXTENT_DO_ACCOUNTING, because it also clears metadata reservation, so here we introduce EXTENT_CLEAR_DATA_RESV flag to indicate btrfs_clear_bit_hook() to update btrfs_space_info's bytes_may_use. Meanwhile __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() internally for both sucessful and failed path, btrfs_prealloc_file_range()'s callers does not need to call btrfs_free_reserved_data_space() any more. Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2016-07-25 15:51:40 +08:00
else
btrfs_free_reserved_data_space(BTRFS_I(inode),
btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges [BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-27 15:10:39 +08:00
data_reserved, range->start,
range->len);
list_del(&range->list);
kfree(range);
}
if (ret < 0)
goto out_unlock;
/*
* We didn't need to allocate any more space, but we still extended the
* size of the file so we need to update i_size and the inode item.
*/
ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
out_unlock:
unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
&cached_state);
out:
btrfs: exclude mmap from happening during all fallocate operations There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-11 06:14:36 +08:00
btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
/* Let go of our reservation. */
if (ret != 0 && !(mode & FALLOC_FL_ZERO_RANGE))
btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
cur_offset, alloc_end - cur_offset);
extent_changeset_free(data_reserved);
return ret;
}
static loff_t find_desired_extent(struct btrfs_inode *inode, loff_t offset,
int whence)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_map *em = NULL;
struct extent_state *cached_state = NULL;
loff_t i_size = inode->vfs_inode.i_size;
Btrfs: fix up bounds checking in lseek An user reported this, it is because that lseek's SEEK_SET/SEEK_CUR/SEEK_END allow a negative value for @offset, but btrfs's SEEK_DATA/SEEK_HOLE don't prepare for that and convert the negative @offset into unsigned type, so we get (end < start) warning. [ 1269.835374] ------------[ cut here ]------------ [ 1269.836809] WARNING: CPU: 0 PID: 1241 at fs/btrfs/extent_io.c:430 insert_state+0x11d/0x140() [ 1269.838816] BTRFS: end < start 4094 18446744073709551615 [ 1269.840334] CPU: 0 PID: 1241 Comm: a.out Tainted: G W 3.16.0+ #306 [ 1269.858229] Call Trace: [ 1269.858612] [<ffffffff81801a69>] dump_stack+0x4e/0x68 [ 1269.858952] [<ffffffff8107894c>] warn_slowpath_common+0x8c/0xc0 [ 1269.859416] [<ffffffff81078a36>] warn_slowpath_fmt+0x46/0x50 [ 1269.859929] [<ffffffff813b0fbd>] insert_state+0x11d/0x140 [ 1269.860409] [<ffffffff813b1396>] __set_extent_bit+0x3b6/0x4e0 [ 1269.860805] [<ffffffff813b21c7>] lock_extent_bits+0x87/0x200 [ 1269.861697] [<ffffffff813a5b28>] btrfs_file_llseek+0x148/0x2a0 [ 1269.862168] [<ffffffff811f201e>] SyS_lseek+0xae/0xc0 [ 1269.862620] [<ffffffff8180b212>] system_call_fastpath+0x16/0x1b [ 1269.862970] ---[ end trace 4d33ea885832054b ]--- This assumes that btrfs starts finding DATA/HOLE from the beginning of file if the assigned @offset is negative. Also we add alignment for lock_extent_bits 's range. Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-16 17:49:30 +08:00
u64 lockstart;
u64 lockend;
u64 start;
u64 len;
int ret = 0;
if (i_size == 0 || offset >= i_size)
Btrfs: fix up bounds checking in lseek An user reported this, it is because that lseek's SEEK_SET/SEEK_CUR/SEEK_END allow a negative value for @offset, but btrfs's SEEK_DATA/SEEK_HOLE don't prepare for that and convert the negative @offset into unsigned type, so we get (end < start) warning. [ 1269.835374] ------------[ cut here ]------------ [ 1269.836809] WARNING: CPU: 0 PID: 1241 at fs/btrfs/extent_io.c:430 insert_state+0x11d/0x140() [ 1269.838816] BTRFS: end < start 4094 18446744073709551615 [ 1269.840334] CPU: 0 PID: 1241 Comm: a.out Tainted: G W 3.16.0+ #306 [ 1269.858229] Call Trace: [ 1269.858612] [<ffffffff81801a69>] dump_stack+0x4e/0x68 [ 1269.858952] [<ffffffff8107894c>] warn_slowpath_common+0x8c/0xc0 [ 1269.859416] [<ffffffff81078a36>] warn_slowpath_fmt+0x46/0x50 [ 1269.859929] [<ffffffff813b0fbd>] insert_state+0x11d/0x140 [ 1269.860409] [<ffffffff813b1396>] __set_extent_bit+0x3b6/0x4e0 [ 1269.860805] [<ffffffff813b21c7>] lock_extent_bits+0x87/0x200 [ 1269.861697] [<ffffffff813a5b28>] btrfs_file_llseek+0x148/0x2a0 [ 1269.862168] [<ffffffff811f201e>] SyS_lseek+0xae/0xc0 [ 1269.862620] [<ffffffff8180b212>] system_call_fastpath+0x16/0x1b [ 1269.862970] ---[ end trace 4d33ea885832054b ]--- This assumes that btrfs starts finding DATA/HOLE from the beginning of file if the assigned @offset is negative. Also we add alignment for lock_extent_bits 's range. Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-16 17:49:30 +08:00
return -ENXIO;
/*
* offset can be negative, in this case we start finding DATA/HOLE from
Btrfs: fix up bounds checking in lseek An user reported this, it is because that lseek's SEEK_SET/SEEK_CUR/SEEK_END allow a negative value for @offset, but btrfs's SEEK_DATA/SEEK_HOLE don't prepare for that and convert the negative @offset into unsigned type, so we get (end < start) warning. [ 1269.835374] ------------[ cut here ]------------ [ 1269.836809] WARNING: CPU: 0 PID: 1241 at fs/btrfs/extent_io.c:430 insert_state+0x11d/0x140() [ 1269.838816] BTRFS: end < start 4094 18446744073709551615 [ 1269.840334] CPU: 0 PID: 1241 Comm: a.out Tainted: G W 3.16.0+ #306 [ 1269.858229] Call Trace: [ 1269.858612] [<ffffffff81801a69>] dump_stack+0x4e/0x68 [ 1269.858952] [<ffffffff8107894c>] warn_slowpath_common+0x8c/0xc0 [ 1269.859416] [<ffffffff81078a36>] warn_slowpath_fmt+0x46/0x50 [ 1269.859929] [<ffffffff813b0fbd>] insert_state+0x11d/0x140 [ 1269.860409] [<ffffffff813b1396>] __set_extent_bit+0x3b6/0x4e0 [ 1269.860805] [<ffffffff813b21c7>] lock_extent_bits+0x87/0x200 [ 1269.861697] [<ffffffff813a5b28>] btrfs_file_llseek+0x148/0x2a0 [ 1269.862168] [<ffffffff811f201e>] SyS_lseek+0xae/0xc0 [ 1269.862620] [<ffffffff8180b212>] system_call_fastpath+0x16/0x1b [ 1269.862970] ---[ end trace 4d33ea885832054b ]--- This assumes that btrfs starts finding DATA/HOLE from the beginning of file if the assigned @offset is negative. Also we add alignment for lock_extent_bits 's range. Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-16 17:49:30 +08:00
* the very start of the file.
*/
start = max_t(loff_t, 0, offset);
Btrfs: fix up bounds checking in lseek An user reported this, it is because that lseek's SEEK_SET/SEEK_CUR/SEEK_END allow a negative value for @offset, but btrfs's SEEK_DATA/SEEK_HOLE don't prepare for that and convert the negative @offset into unsigned type, so we get (end < start) warning. [ 1269.835374] ------------[ cut here ]------------ [ 1269.836809] WARNING: CPU: 0 PID: 1241 at fs/btrfs/extent_io.c:430 insert_state+0x11d/0x140() [ 1269.838816] BTRFS: end < start 4094 18446744073709551615 [ 1269.840334] CPU: 0 PID: 1241 Comm: a.out Tainted: G W 3.16.0+ #306 [ 1269.858229] Call Trace: [ 1269.858612] [<ffffffff81801a69>] dump_stack+0x4e/0x68 [ 1269.858952] [<ffffffff8107894c>] warn_slowpath_common+0x8c/0xc0 [ 1269.859416] [<ffffffff81078a36>] warn_slowpath_fmt+0x46/0x50 [ 1269.859929] [<ffffffff813b0fbd>] insert_state+0x11d/0x140 [ 1269.860409] [<ffffffff813b1396>] __set_extent_bit+0x3b6/0x4e0 [ 1269.860805] [<ffffffff813b21c7>] lock_extent_bits+0x87/0x200 [ 1269.861697] [<ffffffff813a5b28>] btrfs_file_llseek+0x148/0x2a0 [ 1269.862168] [<ffffffff811f201e>] SyS_lseek+0xae/0xc0 [ 1269.862620] [<ffffffff8180b212>] system_call_fastpath+0x16/0x1b [ 1269.862970] ---[ end trace 4d33ea885832054b ]--- This assumes that btrfs starts finding DATA/HOLE from the beginning of file if the assigned @offset is negative. Also we add alignment for lock_extent_bits 's range. Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-16 17:49:30 +08:00
lockstart = round_down(start, fs_info->sectorsize);
lockend = round_up(i_size, fs_info->sectorsize);
if (lockend <= lockstart)
lockend = lockstart + fs_info->sectorsize;
lockend--;
len = lockend - lockstart + 1;
lock_extent_bits(&inode->io_tree, lockstart, lockend, &cached_state);
while (start < i_size) {
em = btrfs_get_extent_fiemap(inode, start, len);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
em = NULL;
break;
}
if (whence == SEEK_HOLE &&
(em->block_start == EXTENT_MAP_HOLE ||
test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
break;
else if (whence == SEEK_DATA &&
(em->block_start != EXTENT_MAP_HOLE &&
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
break;
start = em->start + em->len;
free_extent_map(em);
em = NULL;
cond_resched();
}
free_extent_map(em);
unlock_extent_cached(&inode->io_tree, lockstart, lockend,
&cached_state);
if (ret) {
offset = ret;
} else {
if (whence == SEEK_DATA && start >= i_size)
offset = -ENXIO;
else
offset = min_t(loff_t, start, i_size);
}
return offset;
}
static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
switch (whence) {
default:
return generic_file_llseek(file, offset, whence);
case SEEK_DATA:
case SEEK_HOLE:
btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
offset = find_desired_extent(BTRFS_I(inode), offset, whence);
btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
break;
}
if (offset < 0)
return offset;
return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
}
static int btrfs_file_open(struct inode *inode, struct file *filp)
{
filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
return generic_file_open(inode, filp);
}
static int check_direct_read(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
int ret;
int i, seg;
ret = check_direct_IO(fs_info, iter, offset);
if (ret < 0)
return ret;
if (!iter_is_iovec(iter))
return 0;
for (seg = 0; seg < iter->nr_segs; seg++)
for (i = seg + 1; i < iter->nr_segs; i++)
if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
return -EINVAL;
return 0;
}
static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
return 0;
btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops, 0);
btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
return ret;
}
btrfs: switch to iomap for direct IO We're using direct io implementation based on buffer heads. This patch switches to the new iomap infrastructure. Switch from __blockdev_direct_IO() to iomap_dio_rw(). Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as iomap_begin() for iomap direct I/O functions. This function allocates and locks all the blocks required for the I/O. btrfs_submit_direct() is used as the submit_io() hook for direct I/O ops. Since we need direct I/O reads to go through iomap_dio_rw(), we change file_operations.read_iter() to a btrfs_file_read_iter() which calls btrfs_direct_IO() for direct reads and falls back to generic_file_buffered_read() for incomplete reads and buffered reads. We don't need address_space.direct_IO() anymore: set it to noop. Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is capable of direct I/O reads from a hole, so we don't need to return -ENOENT. Btrfs direct I/O is now done under i_rwsem, shared in case of reads and exclusive in case of writes. This guards against simultaneous truncates. Use iomap->iomap_end() to check for failed or incomplete direct I/O: - for writes, call __endio_write_update_ordered() - for reads, unlock extents btrfs_dio_data is now hooked in iomap->private and not current->journal_info. It carries the reservation variable and the amount of data submitted, so we can calculate the amount of data to call __endio_write_update_ordered in case of an error. This patch removes last use of struct buffer_head from btrfs. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-18 00:18:21 +08:00
static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret = 0;
if (iocb->ki_flags & IOCB_DIRECT) {
ret = btrfs_direct_read(iocb, to);
btrfs: don't fallback to buffered read if we don't need to Since we switched to the iomap infrastructure in b5ff9f1a96e8f ("btrfs: switch to iomap for direct IO") we're calling generic_file_buffered_read() directly and not via generic_file_read_iter() anymore. If the read could read everything there is no need to bother calling generic_file_buffered_read(), like it is handled in generic_file_read_iter(). If we call generic_file_buffered_read() in this case we can hit a situation where we do an invalid readahead and cause this UBSAN splat in fstest generic/091: run fstests generic/091 at 2020-10-21 10:52:32 ================================================================================ UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13 shift exponent 64 is too large for 64-bit type 'long unsigned int' CPU: 0 PID: 656 Comm: fsx Not tainted 5.9.0-rc7+ #821 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 dump_stack+0x57/0x70 lib/dump_stack.c:118 ubsan_epilogue+0x5/0x40 lib/ubsan.c:148 __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe9 lib/ubsan.c:395 __roundup_pow_of_two ./include/linux/log2.h:57 get_init_ra_size mm/readahead.c:318 ondemand_readahead.cold+0x16/0x2c mm/readahead.c:530 generic_file_buffered_read+0x3ac/0x840 mm/filemap.c:2199 call_read_iter ./include/linux/fs.h:1876 new_sync_read+0x102/0x180 fs/read_write.c:415 vfs_read+0x11c/0x1a0 fs/read_write.c:481 ksys_read+0x4f/0xc0 fs/read_write.c:615 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 arch/x86/entry/entry_64.S:118 RIP: 0033:0x7fe87fee992e RSP: 002b:00007ffe01605278 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000004f000 RCX: 00007fe87fee992e RDX: 0000000000004000 RSI: 0000000001677000 RDI: 0000000000000003 RBP: 000000000004f000 R08: 0000000000004000 R09: 000000000004f000 R10: 0000000000053000 R11: 0000000000000246 R12: 0000000000004000 R13: 0000000000000000 R14: 000000000007a120 R15: 0000000000000000 ================================================================================ BTRFS info (device nullb0): has skinny extents BTRFS info (device nullb0): ZONED mode enabled, zone size 268435456 B BTRFS info (device nullb0): enabling ssd optimizations Fixes: f85781fb505e ("btrfs: switch to iomap for direct IO") Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-22 22:05:05 +08:00
if (ret < 0 || !iov_iter_count(to) ||
iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))
btrfs: switch to iomap for direct IO We're using direct io implementation based on buffer heads. This patch switches to the new iomap infrastructure. Switch from __blockdev_direct_IO() to iomap_dio_rw(). Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as iomap_begin() for iomap direct I/O functions. This function allocates and locks all the blocks required for the I/O. btrfs_submit_direct() is used as the submit_io() hook for direct I/O ops. Since we need direct I/O reads to go through iomap_dio_rw(), we change file_operations.read_iter() to a btrfs_file_read_iter() which calls btrfs_direct_IO() for direct reads and falls back to generic_file_buffered_read() for incomplete reads and buffered reads. We don't need address_space.direct_IO() anymore: set it to noop. Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is capable of direct I/O reads from a hole, so we don't need to return -ENOENT. Btrfs direct I/O is now done under i_rwsem, shared in case of reads and exclusive in case of writes. This guards against simultaneous truncates. Use iomap->iomap_end() to check for failed or incomplete direct I/O: - for writes, call __endio_write_update_ordered() - for reads, unlock extents btrfs_dio_data is now hooked in iomap->private and not current->journal_info. It carries the reservation variable and the amount of data submitted, so we can calculate the amount of data to call __endio_write_update_ordered in case of an error. This patch removes last use of struct buffer_head from btrfs. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-18 00:18:21 +08:00
return ret;
}
return filemap_read(iocb, to, ret);
btrfs: switch to iomap for direct IO We're using direct io implementation based on buffer heads. This patch switches to the new iomap infrastructure. Switch from __blockdev_direct_IO() to iomap_dio_rw(). Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as iomap_begin() for iomap direct I/O functions. This function allocates and locks all the blocks required for the I/O. btrfs_submit_direct() is used as the submit_io() hook for direct I/O ops. Since we need direct I/O reads to go through iomap_dio_rw(), we change file_operations.read_iter() to a btrfs_file_read_iter() which calls btrfs_direct_IO() for direct reads and falls back to generic_file_buffered_read() for incomplete reads and buffered reads. We don't need address_space.direct_IO() anymore: set it to noop. Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is capable of direct I/O reads from a hole, so we don't need to return -ENOENT. Btrfs direct I/O is now done under i_rwsem, shared in case of reads and exclusive in case of writes. This guards against simultaneous truncates. Use iomap->iomap_end() to check for failed or incomplete direct I/O: - for writes, call __endio_write_update_ordered() - for reads, unlock extents btrfs_dio_data is now hooked in iomap->private and not current->journal_info. It carries the reservation variable and the amount of data submitted, so we can calculate the amount of data to call __endio_write_update_ordered in case of an error. This patch removes last use of struct buffer_head from btrfs. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-18 00:18:21 +08:00
}
const struct file_operations btrfs_file_operations = {
.llseek = btrfs_file_llseek,
btrfs: switch to iomap for direct IO We're using direct io implementation based on buffer heads. This patch switches to the new iomap infrastructure. Switch from __blockdev_direct_IO() to iomap_dio_rw(). Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as iomap_begin() for iomap direct I/O functions. This function allocates and locks all the blocks required for the I/O. btrfs_submit_direct() is used as the submit_io() hook for direct I/O ops. Since we need direct I/O reads to go through iomap_dio_rw(), we change file_operations.read_iter() to a btrfs_file_read_iter() which calls btrfs_direct_IO() for direct reads and falls back to generic_file_buffered_read() for incomplete reads and buffered reads. We don't need address_space.direct_IO() anymore: set it to noop. Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is capable of direct I/O reads from a hole, so we don't need to return -ENOENT. Btrfs direct I/O is now done under i_rwsem, shared in case of reads and exclusive in case of writes. This guards against simultaneous truncates. Use iomap->iomap_end() to check for failed or incomplete direct I/O: - for writes, call __endio_write_update_ordered() - for reads, unlock extents btrfs_dio_data is now hooked in iomap->private and not current->journal_info. It carries the reservation variable and the amount of data submitted, so we can calculate the amount of data to call __endio_write_update_ordered in case of an error. This patch removes last use of struct buffer_head from btrfs. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-18 00:18:21 +08:00
.read_iter = btrfs_file_read_iter,
.splice_read = generic_file_splice_read,
.write_iter = btrfs_file_write_iter,
.splice_write = iter_file_splice_write,
.mmap = btrfs_file_mmap,
.open = btrfs_file_open,
.release = btrfs_release_file,
.fsync = btrfs_sync_file,
.fallocate = btrfs_fallocate,
.unlocked_ioctl = btrfs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_compat_ioctl,
#endif
.remap_file_range = btrfs_remap_file_range,
};
void __cold btrfs_auto_defrag_exit(void)
{
kmem_cache_destroy(btrfs_inode_defrag_cachep);
}
int __init btrfs_auto_defrag_init(void)
{
btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
sizeof(struct inode_defrag), 0,
SLAB_MEM_SPREAD,
NULL);
if (!btrfs_inode_defrag_cachep)
return -ENOMEM;
return 0;
}
int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
{
int ret;
/*
* So with compression we will find and lock a dirty page and clear the
* first one as dirty, setup an async extent, and immediately return
* with the entire range locked but with nobody actually marked with
* writeback. So we can't just filemap_write_and_wait_range() and
* expect it to work since it will just kick off a thread to do the
* actual work. So we need to call filemap_fdatawrite_range _again_
* since it will wait on the page lock, which won't be unlocked until
* after the pages have been marked as writeback and so we're good to go
* from there. We have to do this otherwise we'll miss the ordered
* extents and that results in badness. Please Josef, do not think you
* know better and pull this out at some point in the future, it is
* right and you are wrong.
*/
ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
&BTRFS_I(inode)->runtime_flags))
ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
return ret;
}