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Merge tag 'for-5.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few regressions and fixes for stable.
Regressions:
- fix a race leading to metadata space leak after task received a
signal
- un-deprecate 2 ioctls, marked as deprecated by mistake
Fixes:
- fix limit check for number of devices during chunk allocation
- fix a race due to double evaluation of i_size_read inside max()
macro, can cause a crash
- remove wrong device id check in tree-checker"
* tag 'for-5.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: un-deprecate ioctls START_SYNC and WAIT_SYNC
btrfs: save i_size to avoid double evaluation of i_size_read in compress_file_range
Btrfs: fix race leading to metadata space leak after task received signal
btrfs: tree-checker: Fix wrong check on max devid
btrfs: Consider system chunk array size for new SYSTEM chunks
The two ioctls START_SYNC and WAIT_SYNC were mistakenly marked as
deprecated and scheduled for removal but we actualy do use them for
'btrfs subvolume delete -C/-c'. The deprecated thing in ebc87351e5
should have been just the async flag for subvolume creation.
The deprecation has been added in this development cycle, remove it
until it's time.
Fixes: ebc87351e5 ("btrfs: Deprecate BTRFS_SUBVOL_CREATE_ASYNC flag")
Signed-off-by: David Sterba <dsterba@suse.com>
We hit a regression while rolling out 5.2 internally where we were
hitting the following panic
kernel BUG at mm/page-writeback.c:2659!
RIP: 0010:clear_page_dirty_for_io+0xe6/0x1f0
Call Trace:
__process_pages_contig+0x25a/0x350
? extent_clear_unlock_delalloc+0x43/0x70
submit_compressed_extents+0x359/0x4d0
normal_work_helper+0x15a/0x330
process_one_work+0x1f5/0x3f0
worker_thread+0x2d/0x3d0
? rescuer_thread+0x340/0x340
kthread+0x111/0x130
? kthread_create_on_node+0x60/0x60
ret_from_fork+0x1f/0x30
This is happening because the page is not locked when doing
clear_page_dirty_for_io. Looking at the core dump it was because our
async_extent had a ram_size of 24576 but our async_chunk range only
spanned 20480, so we had a whole extra page in our ram_size for our
async_extent.
This happened because we try not to compress pages outside of our
i_size, however a cleanup patch changed us to do
actual_end = min_t(u64, i_size_read(inode), end + 1);
which is problematic because i_size_read() can evaluate to different
values in between checking and assigning. So either an expanding
truncate or a fallocate could increase our i_size while we're doing
writeout and actual_end would end up being past the range we have
locked.
I confirmed this was what was happening by installing a debug kernel
that had
actual_end = min_t(u64, i_size_read(inode), end + 1);
if (actual_end > end + 1) {
printk(KERN_ERR "KABOOM\n");
actual_end = end + 1;
}
and installing it onto 500 boxes of the tier that had been seeing the
problem regularly. Last night I got my debug message and no panic,
confirming what I expected.
[ dsterba: the assembly confirms a tiny race window:
mov 0x20(%rsp),%rax
cmp %rax,0x48(%r15) # read
movl $0x0,0x18(%rsp)
mov %rax,%r12
mov %r14,%rax
cmovbe 0x48(%r15),%r12 # eval
Where r15 is inode and 0x48 is offset of i_size.
The original fix was to revert 62b3762271 that would do an
intermediate assignment and this would also avoid the doulble
evaluation but is not future-proof, should the compiler merge the
stores and call i_size_read anyway.
There's a patch adding READ_ONCE to i_size_read but that's not being
applied at the moment and we need to fix the bug. Instead, emulate
READ_ONCE by two barrier()s that's what effectively happens. The
assembly confirms single evaluation:
mov 0x48(%rbp),%rax # read once
mov 0x20(%rsp),%rcx
mov $0x20,%edx
cmp %rax,%rcx
cmovbe %rcx,%rax
mov %rax,(%rsp)
mov %rax,%rcx
mov %r14,%rax
Where 0x48(%rbp) is inode->i_size stored to %eax.
]
Fixes: 62b3762271 ("btrfs: Remove isize local variable in compress_file_range")
CC: stable@vger.kernel.org # v5.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ changelog updated ]
Signed-off-by: David Sterba <dsterba@suse.com>
When a task that is allocating metadata needs to wait for the async
reclaim job to process its ticket and gets a signal (because it was killed
for example) before doing the wait, the task ends up erroring out but
with space reserved for its ticket, which never gets released, resulting
in a metadata space leak (more specifically a leak in the bytes_may_use
counter of the metadata space_info object).
Here's the sequence of steps leading to the space leak:
1) A task tries to create a file for example, so it ends up trying to
start a transaction at btrfs_create();
2) The filesystem is currently in a state where there is not enough
metadata free space to satisfy the transaction's needs. So at
space-info.c:__reserve_metadata_bytes() we create a ticket and
add it to the list of tickets of the space info object. Also,
because the metadata async reclaim job is not running, we queue
a job ro run metadata reclaim;
3) In the meanwhile the task receives a signal (like SIGTERM from
a kill command for example);
4) After queing the async reclaim job, at __reserve_metadata_bytes(),
we unlock the metadata space info and call handle_reserve_ticket();
5) That last function calls wait_reserve_ticket(), which acquires the
lock from the metadata space info. Then in the first iteration of
its while loop, it calls prepare_to_wait_event(), which returns
-ERESTARTSYS because the task has a pending signal. As a result,
we set the error field of the ticket to -EINTR and exit the while
loop without deleting the ticket from the list of tickets (in the
space info object). After exiting the loop we unlock the space info;
6) The async reclaim job is able to release enough metadata, acquires
the metadata space info's lock and then reserves space for the ticket,
since the ticket is still in the list of (non-priority) tickets. The
space reservation happens at btrfs_try_granting_tickets(), called from
maybe_fail_all_tickets(). This increments the bytes_may_use counter
from the metadata space info object, sets the ticket's bytes field to
zero (meaning success, that space was reserved) and removes it from
the list of tickets;
7) wait_reserve_ticket() returns, with the error field of the ticket
set to -EINTR. Then handle_reserve_ticket() just propagates that error
to the caller. Because an error was returned, the caller does not
release the reserved space, since the expectation is that any error
means no space was reserved.
Fix this by removing the ticket from the list, while holding the space
info lock, at wait_reserve_ticket() when prepare_to_wait_event() returns
an error.
Also add some comments and an assertion to guarantee we never end up with
a ticket that has an error set and a bytes counter field set to zero, to
more easily detect regressions in the future.
This issue could be triggered sporadically by some test cases from fstests
such as generic/269 for example, which tries to fill a filesystem and then
kills fsstress processes running in the background.
When this issue happens, we get a warning in syslog/dmesg when unmounting
the filesystem, like the following:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 13240 at fs/btrfs/block-group.c:3186 btrfs_free_block_groups+0x314/0x470 [btrfs]
(...)
CPU: 0 PID: 13240 Comm: umount Tainted: G W L 5.3.0-rc8-btrfs-next-48+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
RIP: 0010:btrfs_free_block_groups+0x314/0x470 [btrfs]
(...)
RSP: 0018:ffff9910c14cfdb8 EFLAGS: 00010286
RAX: 0000000000000024 RBX: ffff89cd8a4d55f0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff89cdf6a178a8 RDI: ffff89cdf6a178a8
RBP: ffff9910c14cfde8 R08: 0000000000000000 R09: 0000000000000001
R10: ffff89cd4d618040 R11: 0000000000000000 R12: ffff89cd8a4d5508
R13: ffff89cde7c4a600 R14: dead000000000122 R15: dead000000000100
FS: 00007f42754432c0(0000) GS:ffff89cdf6a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd25a47f730 CR3: 000000021f8d6006 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
close_ctree+0x1ad/0x390 [btrfs]
generic_shutdown_super+0x6c/0x110
kill_anon_super+0xe/0x30
btrfs_kill_super+0x12/0xa0 [btrfs]
deactivate_locked_super+0x3a/0x70
cleanup_mnt+0xb4/0x160
task_work_run+0x7e/0xc0
exit_to_usermode_loop+0xfa/0x100
do_syscall_64+0x1cb/0x220
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f4274d2cb37
(...)
RSP: 002b:00007ffcff701d38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000557ebde2f060 RCX: 00007f4274d2cb37
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000557ebde2f240
RBP: 0000557ebde2f240 R08: 0000557ebde2f270 R09: 0000000000000015
R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f427522ee64
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffcff701fc0
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffffb12b561e>] copy_process+0x75e/0x1fd0
softirqs last enabled at (0): [<ffffffffb12b561e>] copy_process+0x75e/0x1fd0
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace bcf4b235461b26f6 ]---
BTRFS info (device sdb): space_info 4 has 19116032 free, is full
BTRFS info (device sdb): space_info total=33554432, used=14176256, pinned=0, reserved=0, may_use=196608, readonly=65536
BTRFS info (device sdb): global_block_rsv: size 0 reserved 0
BTRFS info (device sdb): trans_block_rsv: size 0 reserved 0
BTRFS info (device sdb): chunk_block_rsv: size 0 reserved 0
BTRFS info (device sdb): delayed_block_rsv: size 0 reserved 0
BTRFS info (device sdb): delayed_refs_rsv: size 0 reserved 0
Fixes: 374bf9c5cd ("btrfs: unify error handling for ticket flushing")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
The following script will cause false alert on devid check.
#!/bin/bash
dev1=/dev/test/test
dev2=/dev/test/scratch1
mnt=/mnt/btrfs
umount $dev1 &> /dev/null
umount $dev2 &> /dev/null
umount $mnt &> /dev/null
mkfs.btrfs -f $dev1
mount $dev1 $mnt
_fail()
{
echo "!!! FAILED !!!"
exit 1
}
for ((i = 0; i < 4096; i++)); do
btrfs dev add -f $dev2 $mnt || _fail
btrfs dev del $dev1 $mnt || _fail
dev_tmp=$dev1
dev1=$dev2
dev2=$dev_tmp
done
[CAUSE]
Tree-checker uses BTRFS_MAX_DEVS() and BTRFS_MAX_DEVS_SYS_CHUNK() as
upper limit for devid. But we can have devid holes just like above
script.
So the check for devid is incorrect and could cause false alert.
[FIX]
Just remove the whole devid check. We don't have any hard requirement
for devid assignment.
Furthermore, even devid could get corrupted by a bitflip, we still have
dev extents verification at mount time, so corrupted data won't sneak
in.
This fixes fstests btrfs/194.
Reported-by: Anand Jain <anand.jain@oracle.com>
Fixes: ab4ba2e133 ("btrfs: tree-checker: Verify dev item")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For SYSTEM chunks, despite the regular chunk item size limit, there is
another limit due to system chunk array size.
The extra limit was removed in a refactoring, so add it back.
Fixes: e3ecdb3fde ("btrfs: factor out devs_max setting in __btrfs_alloc_chunk")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fixes of error handling cleanup of metadata accounting with qgroups
enabled
- fix swapped values for qgroup tracepoints
- fix race when handling full sync flag
- don't start unused worker thread, functionality removed already
* tag 'for-5.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Btrfs: check for the full sync flag while holding the inode lock during fsync
Btrfs: fix qgroup double free after failure to reserve metadata for delalloc
btrfs: tracepoints: Fix bad entry members of qgroup events
btrfs: tracepoints: Fix wrong parameter order for qgroup events
btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents()
btrfs: don't needlessly create extent-refs kernel thread
btrfs: block-group: Fix a memory leak due to missing btrfs_put_block_group()
Btrfs: add missing extents release on file extent cluster relocation error
We were checking for the full fsync flag in the inode before locking the
inode, which is racy, since at that that time it might not be set but
after we acquire the inode lock some other task set it. One case where
this can happen is on a system low on memory and some concurrent task
failed to allocate an extent map and therefore set the full sync flag on
the inode, to force the next fsync to work in full mode.
A consequence of missing the full fsync flag set is hitting the problems
fixed by commit 0c713cbab6 ("Btrfs: fix race between ranged fsync and
writeback of adjacent ranges"), BUG_ON() when dropping extents from a log
tree, hitting assertion failures at tree-log.c:copy_items() or all sorts
of weird inconsistencies after replaying a log due to file extents items
representing ranges that overlap.
So just move the check such that it's done after locking the inode and
before starting writeback again.
Fixes: 0c713cbab6 ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we fail to reserve metadata for delalloc operations we end up releasing
the previously reserved qgroup amount twice, once explicitly under the
'out_qgroup' label by calling btrfs_qgroup_free_meta_prealloc() and once
again, under label 'out_fail', by calling btrfs_inode_rsv_release() with a
value of 'true' for its 'qgroup_free' argument, which results in
btrfs_qgroup_free_meta_prealloc() being called again, so we end up having
a double free.
Also if we fail to reserve the necessary qgroup amount, we jump to the
label 'out_fail', which calls btrfs_inode_rsv_release() and that in turns
calls btrfs_qgroup_free_meta_prealloc(), even though we weren't able to
reserve any qgroup amount. So we freed some amount we never reserved.
So fix this by removing the call to btrfs_inode_rsv_release() in the
failure path, since it's not necessary at all as we haven't changed the
inode's block reserve in any way at this point.
Fixes: c8eaeac7b7 ("btrfs: reserve delalloc metadata differently")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
For btrfs:qgroup_meta_reserve event, the trace event can output garbage:
qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2
The diff should always be alinged to sector size (4k), so there is
definitely something wrong.
[CAUSE]
For the wrong @diff, it's caused by wrong parameter order.
The correct parameters are:
struct btrfs_root, s64 diff, int type.
However the parameters used are:
struct btrfs_root, int type, s64 diff.
Fixes: 4ee0d8832c ("btrfs: qgroup: Update trace events for metadata reservation")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[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 336a8bb8e3 ("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 f5fef45936 ("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: 43b18595d6 ("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>
The patch 32b593bfcb ("Btrfs: remove no longer used function to run
delayed refs asynchronously") removed the async delayed refs but the
thread has been created, without any use. Remove it to avoid resource
consumption.
Fixes: 32b593bfcb ("Btrfs: remove no longer used function to run delayed refs asynchronously")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_read_block_groups(), if we have an invalid block group which
has mixed type (DATA|METADATA) while the fs doesn't have MIXED_GROUPS
feature, we error out without freeing the block group cache.
This patch will add the missing btrfs_put_block_group() to prevent
memory leak.
Note for stable backports: the file to patch in versions <= 5.3 is
fs/btrfs/extent-tree.c
Fixes: 49303381f1 ("Btrfs: bail out if block group has different mixed flag")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we error out when finding a page at relocate_file_extent_cluster(), we
need to release the outstanding extents counter on the relocation inode,
set by the previous call to btrfs_delalloc_reserve_metadata(), otherwise
the inode's block reserve size can never decrease to zero and metadata
space is leaked. Therefore add a call to btrfs_delalloc_release_extents()
in case we can't find the target page.
Fixes: 8b62f87bad ("Btrfs: rework outstanding_extents")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more stabitly fixes, one build warning fix.
- fix inode allocation under NOFS context
- fix leak in fiemap due to concurrent append writes
- fix log-root tree updates
- fix balance convert of single profile on 32bit architectures
- silence false positive warning on old GCCs (code moved in rc1)"
* tag 'for-5.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: silence maybe-uninitialized warning in clone_range
btrfs: fix uninitialized ret in ref-verify
btrfs: allocate new inode in NOFS context
btrfs: fix balance convert to single on 32-bit host CPUs
btrfs: fix incorrect updating of log root tree
Btrfs: fix memory leak due to concurrent append writes with fiemap
GCC throws warning message as below:
‘clone_src_i_size’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
^
fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here
u64 clone_src_i_size;
^
The clone_src_i_size is only used as call-by-reference
in a call to get_inode_info().
Silence the warning by initializing clone_src_i_size to 0.
Note that the warning is a false positive and reported by older versions
of GCC (eg. 7.x) but not eg 9.x. As there have been numerous people, the
patch is applied. Setting clone_src_i_size to 0 does not otherwise make
sense and would not do any action in case the code changes in the future.
Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note ]
Signed-off-by: David Sterba <dsterba@suse.com>
Coverity caught a case where we could return with a uninitialized value
in ret in process_leaf. This is actually pretty likely because we could
very easily run into a block group item key and have a garbage value in
ret and think there was an errror. Fix this by initializing ret to 0.
Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: fd708b81d9 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, the command:
btrfs balance start -dconvert=single,soft .
on a Raspberry Pi produces the following kernel message:
BTRFS error (device mmcblk0p2): balance: invalid convert data profile single
This fails because we use is_power_of_2(unsigned long) to validate
the new data profile, the constant for 'single' profile uses bit 48,
and there are only 32 bits in a long on ARM.
Fix by open-coding the check using u64 variables.
Tested by completing the original balance command on several Raspberry
Pis.
Fixes: 818255feec ("btrfs: use common helper instead of open coding a bit test")
CC: stable@vger.kernel.org # 4.20+
Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We've historically had reports of being unable to mount file systems
because the tree log root couldn't be read. Usually this is the "parent
transid failure", but could be any of the related errors, including
"fsid mismatch" or "bad tree block", depending on which block got
allocated.
The modification of the individual log root items are serialized on the
per-log root root_mutex. This means that any modification to the
per-subvol log root_item is completely protected.
However we update the root item in the log root tree outside of the log
root tree log_mutex. We do this in order to allow multiple subvolumes
to be updated in each log transaction.
This is problematic however because when we are writing the log root
tree out we update the super block with the _current_ log root node
information. Since these two operations happen independently of each
other, you can end up updating the log root tree in between writing out
the dirty blocks and setting the super block to point at the current
root.
This means we'll point at the new root node that hasn't been written
out, instead of the one we should be pointing at. Thus whatever garbage
or old block we end up pointing at complains when we mount the file
system later and try to replay the log.
Fix this by copying the log's root item into a local root item copy.
Then once we're safely under the log_root_tree->log_mutex we update the
root item in the log_root_tree. This way we do not modify the
log_root_tree while we're committing it, fixing the problem.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Chris Mason <clm@fb.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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>
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Merge tag 'for-5.4-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A bunch of fixes that accumulated in recent weeks, mostly material for
stable.
Summary:
- fix for regression from 5.3 that prevents to use balance convert
with single profile
- qgroup fixes: rescan race, accounting leak with multiple writers,
potential leak after io failure recovery
- fix for use after free in relocation (reported by KASAN)
- other error handling fixups"
* tag 'for-5.4-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: qgroup: Fix reserved data space leak if we have multiple reserve calls
btrfs: qgroup: Fix the wrong target io_tree when freeing reserved data space
btrfs: Fix a regression which we can't convert to SINGLE profile
btrfs: relocation: fix use-after-free on dead relocation roots
Btrfs: fix race setting up and completing qgroup rescan workers
Btrfs: fix missing error return if writeback for extent buffer never started
btrfs: adjust dirty_metadata_bytes after writeback failure of extent buffer
Btrfs: fix selftests failure due to uninitialized i_mode in test inodes
[BUG]
The following script can cause btrfs qgroup data space leak:
mkfs.btrfs -f $dev
mount $dev -o nospace_cache $mnt
btrfs subv create $mnt/subv
btrfs quota en $mnt
btrfs quota rescan -w $mnt
btrfs qgroup limit 128m $mnt/subv
for (( i = 0; i < 3; i++)); do
# Create 3 64M holes for latter fallocate to fail
truncate -s 192m $mnt/subv/file
xfs_io -c "pwrite 64m 4k" $mnt/subv/file > /dev/null
xfs_io -c "pwrite 128m 4k" $mnt/subv/file > /dev/null
sync
# it's supposed to fail, and each failure will leak at least 64M
# data space
xfs_io -f -c "falloc 0 192m" $mnt/subv/file &> /dev/null
rm $mnt/subv/file
sync
done
# Shouldn't fail after we removed the file
xfs_io -f -c "falloc 0 64m" $mnt/subv/file
[CAUSE]
Btrfs qgroup data reserve code allow multiple reservations to happen on
a single extent_changeset:
E.g:
btrfs_qgroup_reserve_data(inode, &data_reserved, 0, SZ_1M);
btrfs_qgroup_reserve_data(inode, &data_reserved, SZ_1M, SZ_2M);
btrfs_qgroup_reserve_data(inode, &data_reserved, 0, SZ_4M);
Btrfs qgroup code has its internal tracking to make sure we don't
double-reserve in above example.
The only pattern utilizing this feature is in the main while loop of
btrfs_fallocate() function.
However btrfs_qgroup_reserve_data()'s error handling has a bug in that
on error it clears all ranges in the io_tree with EXTENT_QGROUP_RESERVED
flag but doesn't free previously reserved bytes.
This bug has a two fold effect:
- Clearing EXTENT_QGROUP_RESERVED ranges
This is the correct behavior, but it prevents
btrfs_qgroup_check_reserved_leak() to catch the leakage as the
detector is purely EXTENT_QGROUP_RESERVED flag based.
- Leak the previously reserved data bytes.
The bug manifests when N calls to btrfs_qgroup_reserve_data are made and
the last one fails, leaking space reserved in the previous ones.
[FIX]
Also free previously reserved data bytes when btrfs_qgroup_reserve_data
fails.
Fixes: 5247255370 ("btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Under the following case with qgroup enabled, if some error happened
after we have reserved delalloc space, then in error handling path, we
could cause qgroup data space leakage:
From btrfs_truncate_block() in inode.c:
ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
block_start, blocksize);
if (ret)
goto out;
again:
page = find_or_create_page(mapping, index, mask);
if (!page) {
btrfs_delalloc_release_space(inode, data_reserved,
block_start, blocksize, true);
btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
ret = -ENOMEM;
goto out;
}
[CAUSE]
In the above case, btrfs_delalloc_reserve_space() will call
btrfs_qgroup_reserve_data() and mark the io_tree range with
EXTENT_QGROUP_RESERVED flag.
In the error handling path, we have the following call stack:
btrfs_delalloc_release_space()
|- btrfs_free_reserved_data_space()
|- btrsf_qgroup_free_data()
|- __btrfs_qgroup_release_data(reserved=@reserved, free=1)
|- qgroup_free_reserved_data(reserved=@reserved)
|- clear_record_extent_bits();
|- freed += changeset.bytes_changed;
However due to a completion bug, qgroup_free_reserved_data() will clear
EXTENT_QGROUP_RESERVED flag in BTRFS_I(inode)->io_failure_tree, other
than the correct BTRFS_I(inode)->io_tree.
Since io_failure_tree is never marked with that flag,
btrfs_qgroup_free_data() will not free any data reserved space at all,
causing a leakage.
This type of error handling can only be triggered by errors outside of
qgroup code. So EDQUOT error from qgroup can't trigger it.
[FIX]
Fix the wrong target io_tree.
Reported-by: Josef Bacik <josef@toxicpanda.com>
Fixes: bc42bda223 ("btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
With v5.3 kernel, we can't convert to SINGLE profile:
# btrfs balance start -f -dconvert=single $mnt
ERROR: error during balancing '/mnt/btrfs': Invalid argument
# dmesg -t | tail
validate_convert_profile: data profile=0x1000000000000 allowed=0x20 is_valid=1 final=0x1000000000000 ret=1
BTRFS error (device dm-3): balance: invalid convert data profile single
[CAUSE]
With the extra debug output added, it shows that the @allowed bit is
lacking the special in-memory only SINGLE profile bit.
Thus we fail at that (profile & ~allowed) check.
This regression is caused by commit 081db89b13 ("btrfs: use raid_attr
to get allowed profiles for balance conversion") and the fact that we
don't use any bit to indicate SINGLE profile on-disk, but uses special
in-memory only bit to help distinguish different profiles.
[FIX]
Add that BTRFS_AVAIL_ALLOC_BIT_SINGLE to @allowed, so the code should be
the same as it was and fix the regression.
Reported-by: Chris Murphy <lists@colorremedies.com>
Fixes: 081db89b13 ("btrfs: use raid_attr to get allowed profiles for balance conversion")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
One user reported a reproducible KASAN report about use-after-free:
BTRFS info (device sdi1): balance: start -dvrange=1256811659264..1256811659265
BTRFS info (device sdi1): relocating block group 1256811659264 flags data|raid0
==================================================================
BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
Write of size 8 at addr ffff88856f671710 by task kworker/u24:10/261579
CPU: 2 PID: 261579 Comm: kworker/u24:10 Tainted: P OE 5.2.11-arch1-1-kasan #4
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X99 Extreme4, BIOS P3.80 04/06/2018
Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs]
Call Trace:
dump_stack+0x7b/0xba
print_address_description+0x6c/0x22e
? btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
__kasan_report.cold+0x1b/0x3b
? btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
kasan_report+0x12/0x17
__asan_report_store8_noabort+0x17/0x20
btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
record_root_in_trans+0x2a0/0x370 [btrfs]
btrfs_record_root_in_trans+0xf4/0x140 [btrfs]
start_transaction+0x1ab/0xe90 [btrfs]
btrfs_join_transaction+0x1d/0x20 [btrfs]
btrfs_finish_ordered_io+0x7bf/0x18a0 [btrfs]
? lock_repin_lock+0x400/0x400
? __kmem_cache_shutdown.cold+0x140/0x1ad
? btrfs_unlink_subvol+0x9b0/0x9b0 [btrfs]
finish_ordered_fn+0x15/0x20 [btrfs]
normal_work_helper+0x1bd/0xca0 [btrfs]
? process_one_work+0x819/0x1720
? kasan_check_read+0x11/0x20
btrfs_endio_write_helper+0x12/0x20 [btrfs]
process_one_work+0x8c9/0x1720
? pwq_dec_nr_in_flight+0x2f0/0x2f0
? worker_thread+0x1d9/0x1030
worker_thread+0x98/0x1030
kthread+0x2bb/0x3b0
? process_one_work+0x1720/0x1720
? kthread_park+0x120/0x120
ret_from_fork+0x35/0x40
Allocated by task 369692:
__kasan_kmalloc.part.0+0x44/0xc0
__kasan_kmalloc.constprop.0+0xba/0xc0
kasan_kmalloc+0x9/0x10
kmem_cache_alloc_trace+0x138/0x260
btrfs_read_tree_root+0x92/0x360 [btrfs]
btrfs_read_fs_root+0x10/0xb0 [btrfs]
create_reloc_root+0x47d/0xa10 [btrfs]
btrfs_init_reloc_root+0x1e2/0x340 [btrfs]
record_root_in_trans+0x2a0/0x370 [btrfs]
btrfs_record_root_in_trans+0xf4/0x140 [btrfs]
start_transaction+0x1ab/0xe90 [btrfs]
btrfs_start_transaction+0x1e/0x20 [btrfs]
__btrfs_prealloc_file_range+0x1c2/0xa00 [btrfs]
btrfs_prealloc_file_range+0x13/0x20 [btrfs]
prealloc_file_extent_cluster+0x29f/0x570 [btrfs]
relocate_file_extent_cluster+0x193/0xc30 [btrfs]
relocate_data_extent+0x1f8/0x490 [btrfs]
relocate_block_group+0x600/0x1060 [btrfs]
btrfs_relocate_block_group+0x3a0/0xa00 [btrfs]
btrfs_relocate_chunk+0x9e/0x180 [btrfs]
btrfs_balance+0x14e4/0x2fc0 [btrfs]
btrfs_ioctl_balance+0x47f/0x640 [btrfs]
btrfs_ioctl+0x119d/0x8380 [btrfs]
do_vfs_ioctl+0x9f5/0x1060
ksys_ioctl+0x67/0x90
__x64_sys_ioctl+0x73/0xb0
do_syscall_64+0xa5/0x370
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 369692:
__kasan_slab_free+0x14f/0x210
kasan_slab_free+0xe/0x10
kfree+0xd8/0x270
btrfs_drop_snapshot+0x154c/0x1eb0 [btrfs]
clean_dirty_subvols+0x227/0x340 [btrfs]
relocate_block_group+0x972/0x1060 [btrfs]
btrfs_relocate_block_group+0x3a0/0xa00 [btrfs]
btrfs_relocate_chunk+0x9e/0x180 [btrfs]
btrfs_balance+0x14e4/0x2fc0 [btrfs]
btrfs_ioctl_balance+0x47f/0x640 [btrfs]
btrfs_ioctl+0x119d/0x8380 [btrfs]
do_vfs_ioctl+0x9f5/0x1060
ksys_ioctl+0x67/0x90
__x64_sys_ioctl+0x73/0xb0
do_syscall_64+0xa5/0x370
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff88856f671100
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1552 bytes inside of
4096-byte region [ffff88856f671100, ffff88856f672100)
The buggy address belongs to the page:
page:ffffea0015bd9c00 refcount:1 mapcount:0 mapping:ffff88864400e600 index:0x0 compound_mapcount: 0
flags: 0x2ffff0000010200(slab|head)
raw: 02ffff0000010200 dead000000000100 dead000000000200 ffff88864400e600
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88856f671600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88856f671680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88856f671700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88856f671780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88856f671800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
BTRFS info (device sdi1): 1 enospc errors during balance
BTRFS info (device sdi1): balance: ended with status: -28
[CAUSE]
The problem happens when finish_ordered_io() get called with balance
still running, while the reloc root of that subvolume is already dead.
(Tree is swap already done, but tree not yet deleted for possible qgroup
usage.)
That means root->reloc_root still exists, but that reloc_root can be
under btrfs_drop_snapshot(), thus we shouldn't access it.
The following race could cause the use-after-free problem:
CPU1 | CPU2
--------------------------------------------------------------------------
| relocate_block_group()
| |- unset_reloc_control(rc)
| |- btrfs_commit_transaction()
btrfs_finish_ordered_io() | |- clean_dirty_subvols()
|- btrfs_join_transaction() | |
|- record_root_in_trans() | |
|- btrfs_init_reloc_root() | |
|- if (root->reloc_root) | |
| | |- root->reloc_root = NULL
| | |- btrfs_drop_snapshot(reloc_root);
|- reloc_root->last_trans|
= trans->transid |
^^^^^^^^^^^^^^^^^^^^^^
Use after free
[FIX]
Fix it by the following modifications:
- Test if the root has dead reloc tree before accessing root->reloc_root
If the root has BTRFS_ROOT_DEAD_RELOC_TREE, then we don't need to
create or update root->reloc_tree
- Clear the BTRFS_ROOT_DEAD_RELOC_TREE flag until we have fully dropped
reloc tree
To co-operate with above modification, so as long as
BTRFS_ROOT_DEAD_RELOC_TREE is still set, we won't try to re-create
reloc tree at record_root_in_trans().
Reported-by: Cebtenzzre <cebtenzzre@gmail.com>
Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
CC: stable@vger.kernel.org # 5.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a race between setting up a qgroup rescan worker and completing
a qgroup rescan worker that can lead to callers of the qgroup rescan wait
ioctl to either not wait for the rescan worker to complete or to hang
forever due to missing wake ups. The following diagram shows a sequence
of steps that illustrates the race.
CPU 1 CPU 2 CPU 3
btrfs_ioctl_quota_rescan()
btrfs_qgroup_rescan()
qgroup_rescan_init()
mutex_lock(&fs_info->qgroup_rescan_lock)
spin_lock(&fs_info->qgroup_lock)
fs_info->qgroup_flags |=
BTRFS_QGROUP_STATUS_FLAG_RESCAN
init_completion(
&fs_info->qgroup_rescan_completion)
fs_info->qgroup_rescan_running = true
mutex_unlock(&fs_info->qgroup_rescan_lock)
spin_unlock(&fs_info->qgroup_lock)
btrfs_init_work()
--> starts the worker
btrfs_qgroup_rescan_worker()
mutex_lock(&fs_info->qgroup_rescan_lock)
fs_info->qgroup_flags &=
~BTRFS_QGROUP_STATUS_FLAG_RESCAN
mutex_unlock(&fs_info->qgroup_rescan_lock)
starts transaction, updates qgroup status
item, etc
btrfs_ioctl_quota_rescan()
btrfs_qgroup_rescan()
qgroup_rescan_init()
mutex_lock(&fs_info->qgroup_rescan_lock)
spin_lock(&fs_info->qgroup_lock)
fs_info->qgroup_flags |=
BTRFS_QGROUP_STATUS_FLAG_RESCAN
init_completion(
&fs_info->qgroup_rescan_completion)
fs_info->qgroup_rescan_running = true
mutex_unlock(&fs_info->qgroup_rescan_lock)
spin_unlock(&fs_info->qgroup_lock)
btrfs_init_work()
--> starts another worker
mutex_lock(&fs_info->qgroup_rescan_lock)
fs_info->qgroup_rescan_running = false
mutex_unlock(&fs_info->qgroup_rescan_lock)
complete_all(&fs_info->qgroup_rescan_completion)
Before the rescan worker started by the task at CPU 3 completes, if
another task calls btrfs_ioctl_quota_rescan(), it will get -EINPROGRESS
because the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN is set at
fs_info->qgroup_flags, which is expected and correct behaviour.
However if other task calls btrfs_ioctl_quota_rescan_wait() before the
rescan worker started by the task at CPU 3 completes, it will return
immediately without waiting for the new rescan worker to complete,
because fs_info->qgroup_rescan_running is set to false by CPU 2.
This race is making test case btrfs/171 (from fstests) to fail often:
btrfs/171 9s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad)
--- tests/btrfs/171.out 2018-09-16 21:30:48.505104287 +0100
+++ /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad 2019-09-19 02:01:36.938486039 +0100
@@ -1,2 +1,3 @@
QA output created by 171
+ERROR: quota rescan failed: Operation now in progress
Silence is golden
...
(Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/171.out /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad' to see the entire diff)
That is because the test calls the btrfs-progs commands "qgroup quota
rescan -w", "qgroup assign" and "qgroup remove" in a sequence that makes
calls to the rescan start ioctl fail with -EINPROGRESS (note the "btrfs"
commands 'qgroup assign' and 'qgroup remove' often call the rescan start
ioctl after calling the qgroup assign ioctl,
btrfs_ioctl_qgroup_assign()), since previous waits didn't actually wait
for a rescan worker to complete.
Another problem the race can cause is missing wake ups for waiters,
since the call to complete_all() happens outside a critical section and
after clearing the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN. In the sequence
diagram above, if we have a waiter for the first rescan task (executed
by CPU 2), then fs_info->qgroup_rescan_completion.wait is not empty, and
if after the rescan worker clears BTRFS_QGROUP_STATUS_FLAG_RESCAN and
before it calls complete_all() against
fs_info->qgroup_rescan_completion, the task at CPU 3 calls
init_completion() against fs_info->qgroup_rescan_completion which
re-initilizes its wait queue to an empty queue, therefore causing the
rescan worker at CPU 2 to call complete_all() against an empty queue,
never waking up the task waiting for that rescan worker.
Fix this by clearing BTRFS_QGROUP_STATUS_FLAG_RESCAN and setting
fs_info->qgroup_rescan_running to false in the same critical section,
delimited by the mutex fs_info->qgroup_rescan_lock, as well as doing the
call to complete_all() in that same critical section. This gives the
protection needed to avoid rescan wait ioctl callers not waiting for a
running rescan worker and the lost wake ups problem, since setting that
rescan flag and boolean as well as initializing the wait queue is done
already in a critical section delimited by that mutex (at
qgroup_rescan_init()).
Fixes: 57254b6ebc ("Btrfs: add ioctl to wait for qgroup rescan completion")
Fixes: d2c609b834 ("btrfs: properly track when rescan worker is running")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If lock_extent_buffer_for_io() fails, it returns a negative value, but its
caller btree_write_cache_pages() ignores such error. This means that a
call to flush_write_bio(), from lock_extent_buffer_for_io(), might have
failed. We should make btree_write_cache_pages() notice such error values
and stop immediatelly, making sure filemap_fdatawrite_range() returns an
error to the transaction commit path. A failure from flush_write_bio()
should also result in the endio callback end_bio_extent_buffer_writepage()
being invoked, which sets the BTRFS_FS_*_ERR bits appropriately, so that
there's no risk a transaction or log commit doesn't catch a writeback
failure.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before, if a eb failed to write out, we would end up triggering a
BUG_ON(). As of f4340622e0 ("btrfs: extent_io: Move the BUG_ON() in
flush_write_bio() one level up"), we no longer BUG_ON(), so we should
make life consistent and add back the unwritten bytes to
dirty_metadata_bytes.
Fixes: f4340622e0 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Filipe Manana <fdmanana@kernel.org>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>
Some of the self tests create a test inode, setup some extents and then do
calls to btrfs_get_extent() to test that the corresponding extent maps
exist and are correct. However btrfs_get_extent(), since the 5.2 merge
window, now errors out when it finds a regular or prealloc extent for an
inode that does not correspond to a regular file (its ->i_mode is not
S_IFREG). This causes the self tests to fail sometimes, specially when
KASAN, slub_debug and page poisoning are enabled:
$ modprobe btrfs
modprobe: ERROR: could not insert 'btrfs': Invalid argument
$ dmesg
[ 9414.691648] Btrfs loaded, crc32c=crc32c-intel, debug=on, assert=on, integrity-checker=on, ref-verify=on
[ 9414.692655] BTRFS: selftest: sectorsize: 4096 nodesize: 4096
[ 9414.692658] BTRFS: selftest: running btrfs free space cache tests
[ 9414.692918] BTRFS: selftest: running extent only tests
[ 9414.693061] BTRFS: selftest: running bitmap only tests
[ 9414.693366] BTRFS: selftest: running bitmap and extent tests
[ 9414.696455] BTRFS: selftest: running space stealing from bitmap to extent tests
[ 9414.697131] BTRFS: selftest: running extent buffer operation tests
[ 9414.697133] BTRFS: selftest: running btrfs_split_item tests
[ 9414.697564] BTRFS: selftest: running extent I/O tests
[ 9414.697583] BTRFS: selftest: running find delalloc tests
[ 9415.081125] BTRFS: selftest: running find_first_clear_extent_bit test
[ 9415.081278] BTRFS: selftest: running extent buffer bitmap tests
[ 9415.124192] BTRFS: selftest: running inode tests
[ 9415.124195] BTRFS: selftest: running btrfs_get_extent tests
[ 9415.127909] BTRFS: selftest: running hole first btrfs_get_extent test
[ 9415.128343] BTRFS critical (device (efault)): regular/prealloc extent found for non-regular inode 256
[ 9415.131428] BTRFS: selftest: fs/btrfs/tests/inode-tests.c:904 expected a real extent, got 0
This happens because the test inodes are created without ever initializing
the i_mode field of the inode, and neither VFS's new_inode() nor the btrfs
callback btrfs_alloc_inode() initialize the i_mode. Initialization of the
i_mode is done through the various callbacks used by the VFS to create
new inodes (regular files, directories, symlinks, tmpfiles, etc), which
all call btrfs_new_inode() which in turn calls inode_init_owner(), which
sets the inode's i_mode. Since the tests only uses new_inode() to create
the test inodes, the i_mode was never initialized.
This always happens on a VM I used with kasan, slub_debug and many other
debug facilities enabled. It also happened to someone who reported this
on bugzilla (on a 5.3-rc).
Fix this by setting i_mode to S_IFREG at btrfs_new_test_inode().
Fixes: 6bf9e4bd6a ("btrfs: inode: Verify inode mode to avoid NULL pointer dereference")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204397
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"This continues with work on code refactoring, sanity checks and space
handling. There are some less user visible changes, nothing that would
particularly stand out.
User visible changes:
- tree checker, more sanity checks of:
- ROOT_ITEM (key, size, generation, level, alignment, flags)
- EXTENT_ITEM and METADATA_ITEM checks (key, size, offset,
alignment, refs)
- tree block reference items
- EXTENT_DATA_REF (key, hash, offset)
- deprecate flag BTRFS_SUBVOL_CREATE_ASYNC for subvolume creation
ioctl, scheduled removal in 5.7
- delete stale and unused UAPI definitions
BTRFS_DEV_REPLACE_ITEM_STATE_*
- improved export of debugging information available via existing
sysfs directory structure
- try harder to delete relations between qgroups and allow to delete
orphan entries
- remove unreliable space checks before relocation starts
Core:
- space handling:
- improved ticket reservations and other high level logic in
order to remove special cases
- factor flushing infrastructure and use it for different
contexts, allows to remove some special case handling
- reduce metadata reservation when only updating inodes
- reduce global block reserve minimum size (affects small
filesystems)
- improved overcommit logic wrt global block reserve
- tests:
- fix memory leaks in extent IO tree
- catch all TRIM range
Fixes:
- fix ENOSPC errors, leading to transaction aborts, when cloning
extents
- several fixes for inode number cache (mount option inode_cache)
- fix potential soft lockups during send when traversing large trees
- fix unaligned access to space cache pages with SLUB debug on
(PowerPC)
Other:
- refactoring public/private functions, moving to new or more
appropriate files
- defines converted to enums
- error handling improvements
- more assertions and comments
- old code deletion"
* tag 'for-5.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (138 commits)
btrfs: Relinquish CPUs in btrfs_compare_trees
btrfs: Don't assign retval of btrfs_try_tree_write_lock/btrfs_tree_read_lock_atomic
btrfs: create structure to encode checksum type and length
btrfs: turn checksum type define into an enum
btrfs: add enospc debug messages for ticket failure
btrfs: do not account global reserve in can_overcommit
btrfs: use btrfs_try_granting_tickets in update_global_rsv
btrfs: always reserve our entire size for the global reserve
btrfs: change the minimum global reserve size
btrfs: rename btrfs_space_info_add_old_bytes
btrfs: remove orig_bytes from reserve_ticket
btrfs: fix may_commit_transaction to deal with no partial filling
btrfs: rework wake_all_tickets
btrfs: refactor the ticket wakeup code
btrfs: stop partially refilling tickets when releasing space
btrfs: add space reservation tracepoint for reserved bytes
btrfs: roll tracepoint into btrfs_space_info_update helper
btrfs: do not allow reservations if we have pending tickets
btrfs: stop clearing EXTENT_DIRTY in inode I/O tree
btrfs: treat RWF_{,D}SYNC writes as sync for CRCs
...
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Merge tag 'for-5.3-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Here are two fixes, one of them urgent fixing a bug introduced in 5.2
and reported by many users. It took time to identify the root cause,
catching the 5.3 release is higly desired also to push the fix to 5.2
stable tree.
The bug is a mess up of return values after adding proper error
handling and honestly the kind of bug that can cause sleeping
disorders until it's caught. My appologies to everybody who was
affected.
Summary of what could happen:
1) either a hang when committing a transaction, if this happens
there's no risk of corruption, still the hang is very inconvenient
and can't be resolved without a reboot
2) writeback for some btree nodes may never be started and we end up
committing a transaction without noticing that, this is really
serious and that will lead to the "parent transid verify failed"
messages"
* tag 'for-5.3-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Btrfs: fix unwritten extent buffers and hangs on future writeback attempts
Btrfs: fix assertion failure during fsync and use of stale transaction
The lock_extent_buffer_io() returns 1 to the caller to tell it everything
went fine and the callers needs to start writeback for the extent buffer
(submit a bio, etc), 0 to tell the caller everything went fine but it does
not need to start writeback for the extent buffer, and a negative value if
some error happened.
When it's about to return 1 it tries to lock all pages, and if a try lock
on a page fails, and we didn't flush any existing bio in our "epd", it
calls flush_write_bio(epd) and overwrites the return value of 1 to 0 or
an error. The page might have been locked elsewhere, not with the goal
of starting writeback of the extent buffer, and even by some code other
than btrfs, like page migration for example, so it does not mean the
writeback of the extent buffer was already started by some other task,
so returning a 0 tells the caller (btree_write_cache_pages()) to not
start writeback for the extent buffer. Note that epd might currently have
either no bio, so flush_write_bio() returns 0 (success) or it might have
a bio for another extent buffer with a lower index (logical address).
Since we return 0 with the EXTENT_BUFFER_WRITEBACK bit set on the
extent buffer and writeback is never started for the extent buffer,
future attempts to writeback the extent buffer will hang forever waiting
on that bit to be cleared, since it can only be cleared after writeback
completes. Such hang is reported with a trace like the following:
[49887.347053] INFO: task btrfs-transacti:1752 blocked for more than 122 seconds.
[49887.347059] Not tainted 5.2.13-gentoo #2
[49887.347060] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[49887.347062] btrfs-transacti D 0 1752 2 0x80004000
[49887.347064] Call Trace:
[49887.347069] ? __schedule+0x265/0x830
[49887.347071] ? bit_wait+0x50/0x50
[49887.347072] ? bit_wait+0x50/0x50
[49887.347074] schedule+0x24/0x90
[49887.347075] io_schedule+0x3c/0x60
[49887.347077] bit_wait_io+0x8/0x50
[49887.347079] __wait_on_bit+0x6c/0x80
[49887.347081] ? __lock_release.isra.29+0x155/0x2d0
[49887.347083] out_of_line_wait_on_bit+0x7b/0x80
[49887.347084] ? var_wake_function+0x20/0x20
[49887.347087] lock_extent_buffer_for_io+0x28c/0x390
[49887.347089] btree_write_cache_pages+0x18e/0x340
[49887.347091] do_writepages+0x29/0xb0
[49887.347093] ? kmem_cache_free+0x132/0x160
[49887.347095] ? convert_extent_bit+0x544/0x680
[49887.347097] filemap_fdatawrite_range+0x70/0x90
[49887.347099] btrfs_write_marked_extents+0x53/0x120
[49887.347100] btrfs_write_and_wait_transaction.isra.4+0x38/0xa0
[49887.347102] btrfs_commit_transaction+0x6bb/0x990
[49887.347103] ? start_transaction+0x33e/0x500
[49887.347105] transaction_kthread+0x139/0x15c
So fix this by not overwriting the return value (ret) with the result
from flush_write_bio(). We also need to clear the EXTENT_BUFFER_WRITEBACK
bit in case flush_write_bio() returns an error, otherwise it will hang
any future attempts to writeback the extent buffer, and undo all work
done before (set back EXTENT_BUFFER_DIRTY, etc).
This is a regression introduced in the 5.2 kernel.
Fixes: 2e3c25136a ("btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()")
Fixes: f4340622e0 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up")
Reported-by: Zdenek Sojka <zsojka@seznam.cz>
Link: https://lore.kernel.org/linux-btrfs/GpO.2yos.3WGDOLpx6t%7D.1TUDYM@seznam.cz/T/#u
Reported-by: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Link: https://lore.kernel.org/linux-btrfs/5c4688ac-10a7-fb07-70e8-c5d31a3fbb38@profihost.ag/T/#t
Reported-by: Drazen Kacar <drazen.kacar@oradian.com>
Link: https://lore.kernel.org/linux-btrfs/DB8PR03MB562876ECE2319B3E579590F799C80@DB8PR03MB5628.eurprd03.prod.outlook.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204377
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Sometimes when fsync'ing a file we need to log that other inodes exist and
when we need to do that we acquire a reference on the inodes and then drop
that reference using iput() after logging them.
That generally is not a problem except if we end up doing the final iput()
(dropping the last reference) on the inode and that inode has a link count
of 0, which can happen in a very short time window if the logging path
gets a reference on the inode while it's being unlinked.
In that case we end up getting the eviction callback, btrfs_evict_inode(),
invoked through the iput() call chain which needs to drop all of the
inode's items from its subvolume btree, and in order to do that, it needs
to join a transaction at the helper function evict_refill_and_join().
However because the task previously started a transaction at the fsync
handler, btrfs_sync_file(), it has current->journal_info already pointing
to a transaction handle and therefore evict_refill_and_join() will get
that transaction handle from btrfs_join_transaction(). From this point on,
two different problems can happen:
1) evict_refill_and_join() will often change the transaction handle's
block reserve (->block_rsv) and set its ->bytes_reserved field to a
value greater than 0. If evict_refill_and_join() never commits the
transaction, the eviction handler ends up decreasing the reference
count (->use_count) of the transaction handle through the call to
btrfs_end_transaction(), and after that point we have a transaction
handle with a NULL ->block_rsv (which is the value prior to the
transaction join from evict_refill_and_join()) and a ->bytes_reserved
value greater than 0. If after the eviction/iput completes the inode
logging path hits an error or it decides that it must fallback to a
transaction commit, the btrfs fsync handle, btrfs_sync_file(), gets a
non-zero value from btrfs_log_dentry_safe(), and because of that
non-zero value it tries to commit the transaction using a handle with
a NULL ->block_rsv and a non-zero ->bytes_reserved value. This makes
the transaction commit hit an assertion failure at
btrfs_trans_release_metadata() because ->bytes_reserved is not zero but
the ->block_rsv is NULL. The produced stack trace for that is like the
following:
[192922.917158] assertion failed: !trans->bytes_reserved, file: fs/btrfs/transaction.c, line: 816
[192922.917553] ------------[ cut here ]------------
[192922.917922] kernel BUG at fs/btrfs/ctree.h:3532!
[192922.918310] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[192922.918666] CPU: 2 PID: 883 Comm: fsstress Tainted: G W 5.1.4-btrfs-next-47 #1
[192922.919035] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[192922.919801] RIP: 0010:assfail.constprop.25+0x18/0x1a [btrfs]
(...)
[192922.920925] RSP: 0018:ffffaebdc8a27da8 EFLAGS: 00010286
[192922.921315] RAX: 0000000000000051 RBX: ffff95c9c16a41c0 RCX: 0000000000000000
[192922.921692] RDX: 0000000000000000 RSI: ffff95cab6b16838 RDI: ffff95cab6b16838
[192922.922066] RBP: ffff95c9c16a41c0 R08: 0000000000000000 R09: 0000000000000000
[192922.922442] R10: ffffaebdc8a27e70 R11: 0000000000000000 R12: ffff95ca731a0980
[192922.922820] R13: 0000000000000000 R14: ffff95ca84c73338 R15: ffff95ca731a0ea8
[192922.923200] FS: 00007f337eda4e80(0000) GS:ffff95cab6b00000(0000) knlGS:0000000000000000
[192922.923579] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[192922.923948] CR2: 00007f337edad000 CR3: 00000001e00f6002 CR4: 00000000003606e0
[192922.924329] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[192922.924711] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[192922.925105] Call Trace:
[192922.925505] btrfs_trans_release_metadata+0x10c/0x170 [btrfs]
[192922.925911] btrfs_commit_transaction+0x3e/0xaf0 [btrfs]
[192922.926324] btrfs_sync_file+0x44c/0x490 [btrfs]
[192922.926731] do_fsync+0x38/0x60
[192922.927138] __x64_sys_fdatasync+0x13/0x20
[192922.927543] do_syscall_64+0x60/0x1c0
[192922.927939] entry_SYSCALL_64_after_hwframe+0x49/0xbe
(...)
[192922.934077] ---[ end trace f00808b12068168f ]---
2) If evict_refill_and_join() decides to commit the transaction, it will
be able to do it, since the nested transaction join only increments the
transaction handle's ->use_count reference counter and it does not
prevent the transaction from getting committed. This means that after
eviction completes, the fsync logging path will be using a transaction
handle that refers to an already committed transaction. What happens
when using such a stale transaction can be unpredictable, we are at
least having a use-after-free on the transaction handle itself, since
the transaction commit will call kmem_cache_free() against the handle
regardless of its ->use_count value, or we can end up silently losing
all the updates to the log tree after that iput() in the logging path,
or using a transaction handle that in the meanwhile was allocated to
another task for a new transaction, etc, pretty much unpredictable
what can happen.
In order to fix both of them, instead of using iput() during logging, use
btrfs_add_delayed_iput(), so that the logging path of fsync never drops
the last reference on an inode, that step is offloaded to a safe context
(usually the cleaner kthread).
The assertion failure issue was sporadically triggered by the test case
generic/475 from fstests, which loads the dm error target while fsstress
is running, which lead to fsync failing while logging inodes with -EIO
errors and then trying later to commit the transaction, triggering the
assertion failure.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing any form of incremental send the parent and the child trees
need to be compared via btrfs_compare_trees. This can result in long
loop chains without ever relinquishing the CPU. This causes softlockup
detector to trigger when comparing trees with a lot of items. Example
report:
watchdog: BUG: soft lockup - CPU#0 stuck for 24s! [snapperd:16153]
CPU: 0 PID: 16153 Comm: snapperd Not tainted 5.2.9-1-default #1 openSUSE Tumbleweed (unreleased)
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
pstate: 40000005 (nZcv daif -PAN -UAO)
pc : __ll_sc_arch_atomic_sub_return+0x14/0x20
lr : btrfs_release_extent_buffer_pages+0xe0/0x1e8 [btrfs]
sp : ffff00001273b7e0
Call trace:
__ll_sc_arch_atomic_sub_return+0x14/0x20
release_extent_buffer+0xdc/0x120 [btrfs]
free_extent_buffer.part.0+0xb0/0x118 [btrfs]
free_extent_buffer+0x24/0x30 [btrfs]
btrfs_release_path+0x4c/0xa0 [btrfs]
btrfs_free_path.part.0+0x20/0x40 [btrfs]
btrfs_free_path+0x24/0x30 [btrfs]
get_inode_info+0xa8/0xf8 [btrfs]
finish_inode_if_needed+0xe0/0x6d8 [btrfs]
changed_cb+0x9c/0x410 [btrfs]
btrfs_compare_trees+0x284/0x648 [btrfs]
send_subvol+0x33c/0x520 [btrfs]
btrfs_ioctl_send+0x8a0/0xaf0 [btrfs]
btrfs_ioctl+0x199c/0x2288 [btrfs]
do_vfs_ioctl+0x4b0/0x820
ksys_ioctl+0x84/0xb8
__arm64_sys_ioctl+0x28/0x38
el0_svc_common.constprop.0+0x7c/0x188
el0_svc_handler+0x34/0x90
el0_svc+0x8/0xc
Fix this by adding a call to cond_resched at the beginning of the main
loop in btrfs_compare_trees.
Fixes: 7069830a9e ("Btrfs: add btrfs_compare_trees function")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Those function are simple boolean predicates there is no need to assign
their return values to interim variables. Use them directly as
predicates. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Create a structure to encode the type and length for the known on-disk
checksums. This makes it easier to add new checksums later.
The structure and helpers are moved from ctree.h so they don't occupy
space in all headers including ctree.h. This save some space in the
final object.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When debugging weird enospc problems it's handy to be able to dump the
space info when we wake up all tickets, and see what the ticket values
are. This helped me figure out cases where we were enospc'ing when we
shouldn't have been.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We ran into a problem in production where a box with plenty of space was
getting wedged doing ENOSPC flushing. These boxes only had 20% of the
disk allocated, but their metadata space + global reserve was right at
the size of their metadata chunk.
In this case can_overcommit should be allowing allocations without
problem, but there's logic in can_overcommit that doesn't allow us to
overcommit if there's not enough real space to satisfy the global
reserve.
This is for historical reasons. Before there were only certain places
we could allocate chunks. We could go to commit the transaction and not
have enough space for our pending delayed refs and such and be unable to
allocate a new chunk. This would result in a abort because of ENOSPC.
This code was added to solve this problem.
However since then we've gained the ability to always be able to
allocate a chunk. So we can easily overcommit in these cases without
risking a transaction abort because of ENOSPC.
Also prior to now the global reserve really would be used because that's
the space we relied on for delayed refs. With delayed refs being
tracked separately we no longer have to worry about running out of
delayed refs space while committing. We are much less likely to
exhaust our global reserve space during transaction commit.
Fix the can_overcommit code to simply see if our current usage + what we
want is less than our current free space plus whatever slack space we
have in the disk is. This solves the problem we were seeing in
production and keeps us from flushing as aggressively as we approach our
actual metadata size usage.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have some annoying xfstests tests that will create a very small fs,
fill it up, delete it, and repeat to make sure everything works right.
This trips btrfs up sometimes because we may commit a transaction to
free space, but most of the free metadata space was being reserved by
the global reserve. So we commit and update the global reserve, but the
space is simply added to bytes_may_use directly, instead of trying to
add it to existing tickets. This results in ENOSPC when we really did
have space. Fix this by calling btrfs_try_granting_tickets once we add
back our excess space to wake any pending tickets.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While messing with the overcommit logic I noticed that sometimes we'd
ENOSPC out when really we should have run out of space much earlier. It
turns out it's because we'll only reserve up to the free amount left in
the space info for the global reserve, but that doesn't make sense with
overcommit because we could be well above our actual size. This results
in the global reserve not carving out it's entire reservation, and thus
not putting enough pressure on the rest of the infrastructure to do the
right thing and ENOSPC out at a convenient time. Fix this by always
taking our full reservation amount for the global reserve.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It made sense to have the global reserve set at 16M in the past, but
since it is used less nowadays set the minimum size to the number of
items we'll need to update the main trees we update during a transaction
commit, plus some slop area so we can do unlinks if we need to.
In practice this doesn't affect normal file systems, but for xfstests
where we do things like fill up a fs and then rm * it can fall over in
weird ways. This enables us for more sane behavior at extremely small
file system sizes.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This name doesn't really fit with how the space reservation stuff works
now, rename it to btrfs_space_info_free_bytes_may_use so it's clear what
the function is doing.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we do not do partial filling of tickets simply remove
orig_bytes, it is no longer needed.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we aren't partially filling tickets we may have some slack
space left in the space_info. We need to account for this in
may_commit_transaction, otherwise we may choose to not commit the
transaction despite it actually having enough space to satisfy our
ticket.
Calculate the free space we have in the space_info, if any, and subtract
this from the ticket we have and use that amount to determine if we will
need to commit to reclaim enough space.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we no longer partially fill tickets we need to rework
wake_all_tickets to call btrfs_try_to_wakeup_tickets() in order to see
if any subsequent tickets are able to be satisfied. If our tickets_id
changes we know something happened and we can keep flushing.
Also if we find a ticket that is smaller than the first ticket in our
queue then we want to retry the flushing loop again in case
may_commit_transaction() decides we could satisfy the ticket by
committing the transaction.
Rename this to maybe_fail_all_tickets() while we're at it, to better
reflect what the function is actually doing.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that btrfs_space_info_add_old_bytes simply checks if we can make the
reservation and updates bytes_may_use, there's no reason to have both
helpers in place.
Factor out the ticket wakeup logic into it's own helper, make
btrfs_space_info_add_old_bytes() update bytes_may_use and then call the
wakeup helper, and replace all calls to btrfs_space_info_add_new_bytes()
with the wakeup helper.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_space_info_add_old_bytes is used when adding the extra space from
an existing reservation back into the space_info to be used by any
waiting tickets. In order to keep us from overcommitting we check to
make sure that we can still use this space for our reserve ticket, and
if we cannot we'll simply subtract it from space_info->bytes_may_use.
However this is problematic, because it assumes that only changes to
bytes_may_use would affect our ability to make reservations. Any
changes to bytes_reserved would be missed. If we were unable to make a
reservation prior because of reserved space, but that reserved space was
free'd due to unlink or truncate and we were allowed to immediately
reclaim that metadata space we would still ENOSPC.
Consider the example where we create a file with a bunch of extents,
using up 2MiB of actual space for the new tree blocks. Then we try to
make a reservation of 2MiB but we do not have enough space to make this
reservation. The iput() occurs in another thread and we remove this
space, and since we did not write the blocks we simply do
space_info->bytes_reserved -= 2MiB. We would never see this because we
do not check our space info used, we just try to re-use the freed
reservations.
To fix this problem, and to greatly simplify the wakeup code, do away
with this partial refilling nonsense. Use
btrfs_space_info_add_old_bytes to subtract the reservation from
space_info->bytes_may_use, and then check the ticket against the total
used of the space_info the same way we do with the initial reservation
attempt.
This keeps the reservation logic consistent and solves the problem of
early ENOSPC in the case that we free up space in places other than
bytes_may_use and bytes_pinned. Thanks,
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I noticed when folding the trace_btrfs_space_reservation() tracepoint
into the btrfs_space_info_update_* helpers that we didn't emit a
tracepoint when doing btrfs_add_reserved_bytes(). I know this is
because we were swapping bytes_may_use for bytes_reserved, so in my mind
there was no reason to have the tracepoint there. But now there is
because we always emit the unreserve for the bytes_may_use side, and
this would have broken if compression was on anyway. Add a tracepoint
to cover the bytes_reserved counter so the math still comes out right.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We duplicate this tracepoint everywhere we call these helpers, so update
the helper to have the tracepoint as well.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Linus Torvalds