OpenCloudOS-Kernel/fs/xfs/xfs_aops.c

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/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_iomap.h"
xfs: event tracing support Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15 07:14:59 +08:00
#include "xfs_trace.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_bmap_btree.h"
#include "xfs_reflink.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/gfp.h>
#include <linux/mpage.h>
#include <linux/pagevec.h>
#include <linux/writeback.h>
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
/*
* structure owned by writepages passed to individual writepage calls
*/
struct xfs_writepage_ctx {
struct xfs_bmbt_irec imap;
bool imap_valid;
unsigned int io_type;
struct xfs_ioend *ioend;
sector_t last_block;
};
xfs: event tracing support Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15 07:14:59 +08:00
void
xfs_count_page_state(
struct page *page,
int *delalloc,
int *unwritten)
{
struct buffer_head *bh, *head;
*delalloc = *unwritten = 0;
bh = head = page_buffers(page);
do {
if (buffer_unwritten(bh))
(*unwritten) = 1;
else if (buffer_delay(bh))
(*delalloc) = 1;
} while ((bh = bh->b_this_page) != head);
}
struct block_device *
xfs_find_bdev_for_inode(
struct inode *inode)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
if (XFS_IS_REALTIME_INODE(ip))
return mp->m_rtdev_targp->bt_bdev;
else
return mp->m_ddev_targp->bt_bdev;
}
struct dax_device *
xfs_find_daxdev_for_inode(
struct inode *inode)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
if (XFS_IS_REALTIME_INODE(ip))
return mp->m_rtdev_targp->bt_daxdev;
else
return mp->m_ddev_targp->bt_daxdev;
}
/*
* We're now finished for good with this page. Update the page state via the
* associated buffer_heads, paying attention to the start and end offsets that
* we need to process on the page.
xfs: bufferhead chains are invalid after end_page_writeback In xfs_finish_page_writeback(), we have a loop that looks like this: do { if (off < bvec->bv_offset) goto next_bh; if (off > end) break; bh->b_end_io(bh, !error); next_bh: off += bh->b_size; } while ((bh = bh->b_this_page) != head); The b_end_io function is end_buffer_async_write(), which will call end_page_writeback() once all the buffers have marked as no longer under IO. This issue here is that the only thing currently protecting both the bufferhead chain and the page from being reclaimed is the PageWriteback state held on the page. While we attempt to limit the loop to just the buffers covered by the IO, we still read from the buffer size and follow the next pointer in the bufferhead chain. There is no guarantee that either of these are valid after the PageWriteback flag has been cleared. Hence, loops like this are completely unsafe, and result in use-after-free issues. One such problem was caught by Calvin Owens with KASAN: ..... INFO: Freed in 0x103fc80ec age=18446651500051355200 cpu=2165122683 pid=-1 free_buffer_head+0x41/0x90 __slab_free+0x1ed/0x340 kmem_cache_free+0x270/0x300 free_buffer_head+0x41/0x90 try_to_free_buffers+0x171/0x240 xfs_vm_releasepage+0xcb/0x3b0 try_to_release_page+0x106/0x190 shrink_page_list+0x118e/0x1a10 shrink_inactive_list+0x42c/0xdf0 shrink_zone_memcg+0xa09/0xfa0 shrink_zone+0x2c3/0xbc0 ..... Call Trace: <IRQ> [<ffffffff81e8b8e4>] dump_stack+0x68/0x94 [<ffffffff8153a995>] print_trailer+0x115/0x1a0 [<ffffffff81541174>] object_err+0x34/0x40 [<ffffffff815436e7>] kasan_report_error+0x217/0x530 [<ffffffff81543b33>] __asan_report_load8_noabort+0x43/0x50 [<ffffffff819d651f>] xfs_destroy_ioend+0x3bf/0x4c0 [<ffffffff819d69d4>] xfs_end_bio+0x154/0x220 [<ffffffff81de0c58>] bio_endio+0x158/0x1b0 [<ffffffff81dff61b>] blk_update_request+0x18b/0xb80 [<ffffffff821baf57>] scsi_end_request+0x97/0x5a0 [<ffffffff821c5558>] scsi_io_completion+0x438/0x1690 [<ffffffff821a8d95>] scsi_finish_command+0x375/0x4e0 [<ffffffff821c3940>] scsi_softirq_done+0x280/0x340 Where the access is occuring during IO completion after the buffer had been freed from direct memory reclaim. Prevent use-after-free accidents in this end_io processing loop by pre-calculating the loop conditionals before calling bh->b_end_io(). The loop is already limited to just the bufferheads covered by the IO in progress, so the offset checks are sufficient to prevent accessing buffers in the chain after end_page_writeback() has been called by the the bh->b_end_io() callout. Yet another example of why Bufferheads Must Die. cc: <stable@vger.kernel.org> # 4.7 Signed-off-by: Dave Chinner <dchinner@redhat.com> Reported-and-Tested-by: Calvin Owens <calvinowens@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-22 07:56:38 +08:00
*
* Note that we open code the action in end_buffer_async_write here so that we
* only have to iterate over the buffers attached to the page once. This is not
* only more efficient, but also ensures that we only calls end_page_writeback
* at the end of the iteration, and thus avoids the pitfall of having the page
* and buffers potentially freed after every call to end_buffer_async_write.
*/
static void
xfs_finish_page_writeback(
struct inode *inode,
struct bio_vec *bvec,
int error)
{
struct buffer_head *head = page_buffers(bvec->bv_page), *bh = head;
bool busy = false;
unsigned int off = 0;
unsigned long flags;
ASSERT(bvec->bv_offset < PAGE_SIZE);
ASSERT((bvec->bv_offset & (i_blocksize(inode) - 1)) == 0);
ASSERT(bvec->bv_offset + bvec->bv_len <= PAGE_SIZE);
ASSERT((bvec->bv_len & (i_blocksize(inode) - 1)) == 0);
local_irq_save(flags);
bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
do {
if (off >= bvec->bv_offset &&
off < bvec->bv_offset + bvec->bv_len) {
ASSERT(buffer_async_write(bh));
ASSERT(bh->b_end_io == NULL);
if (error) {
mark_buffer_write_io_error(bh);
clear_buffer_uptodate(bh);
SetPageError(bvec->bv_page);
} else {
set_buffer_uptodate(bh);
}
clear_buffer_async_write(bh);
unlock_buffer(bh);
} else if (buffer_async_write(bh)) {
ASSERT(buffer_locked(bh));
busy = true;
}
off += bh->b_size;
} while ((bh = bh->b_this_page) != head);
bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
local_irq_restore(flags);
if (!busy)
end_page_writeback(bvec->bv_page);
}
/*
* We're now finished for good with this ioend structure. Update the page
* state, release holds on bios, and finally free up memory. Do not use the
* ioend after this.
*/
STATIC void
xfs_destroy_ioend(
struct xfs_ioend *ioend,
int error)
{
struct inode *inode = ioend->io_inode;
struct bio *bio = &ioend->io_inline_bio;
struct bio *last = ioend->io_bio, *next;
u64 start = bio->bi_iter.bi_sector;
bool quiet = bio_flagged(bio, BIO_QUIET);
for (bio = &ioend->io_inline_bio; bio; bio = next) {
struct bio_vec *bvec;
int i;
/*
* For the last bio, bi_private points to the ioend, so we
* need to explicitly end the iteration here.
*/
if (bio == last)
next = NULL;
else
next = bio->bi_private;
/* walk each page on bio, ending page IO on them */
bio_for_each_segment_all(bvec, bio, i)
xfs_finish_page_writeback(inode, bvec, error);
bio_put(bio);
}
if (unlikely(error && !quiet)) {
xfs_err_ratelimited(XFS_I(inode)->i_mount,
"writeback error on sector %llu", start);
}
}
/*
* Fast and loose check if this write could update the on-disk inode size.
*/
static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend)
{
return ioend->io_offset + ioend->io_size >
XFS_I(ioend->io_inode)->i_d.di_size;
}
STATIC int
xfs_setfilesize_trans_alloc(
struct xfs_ioend *ioend)
{
struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
struct xfs_trans *tp;
int error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
if (error)
return error;
ioend->io_append_trans = tp;
/*
xfs: fix direct IO nested transaction deadlock. The direct IO path can do a nested transaction reservation when writing past the EOF. The first transaction is the append transaction for setting the filesize at IO completion, but we can also need a transaction for allocation of blocks. If the log is low on space due to reservations and small log, the append transaction can be granted after wating for space as the only active transaction in the system. This then attempts a reservation for an allocation, which there isn't space in the log for, and the reservation sleeps. The result is that there is nothing left in the system to wake up all the processes waiting for log space to come free. The stack trace that shows this deadlock is relatively innocuous: xlog_grant_head_wait xlog_grant_head_check xfs_log_reserve xfs_trans_reserve xfs_iomap_write_direct __xfs_get_blocks xfs_get_blocks_direct do_blockdev_direct_IO __blockdev_direct_IO xfs_vm_direct_IO generic_file_direct_write xfs_file_dio_aio_writ xfs_file_aio_write do_sync_write vfs_write This was discovered on a filesystem with a log of only 10MB, and a log stripe unit of 256k whih increased the base reservations by 512k. Hence a allocation transaction requires 1.2MB of log space to be available instead of only 260k, and so greatly increased the chance that there wouldn't be enough log space available for the nested transaction to succeed. The key to reproducing it is this mkfs command: mkfs.xfs -f -d agcount=16,su=256k,sw=12 -l su=256k,size=2560b $SCRATCH_DEV The test case was a 1000 fsstress processes running with random freeze and unfreezes every few seconds. Thanks to Eryu Guan (eguan@redhat.com) for writing the test that found this on a system with a somewhat unique default configuration.... cc: <stable@vger.kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andrew Dahl <adahl@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-28 10:01:00 +08:00
* We may pass freeze protection with a transaction. So tell lockdep
* we released it.
*/
__sb_writers_release(ioend->io_inode->i_sb, SB_FREEZE_FS);
/*
* We hand off the transaction to the completion thread now, so
* clear the flag here.
*/
current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
return 0;
}
[XFS] Fix to prevent the notorious 'NULL files' problem after a crash. The problem that has been addressed is that of synchronising updates of the file size with writes that extend a file. Without the fix the update of a file's size, as a result of a write beyond eof, is independent of when the cached data is flushed to disk. Often the file size update would be written to the filesystem log before the data is flushed to disk. When a system crashes between these two events and the filesystem log is replayed on mount the file's size will be set but since the contents never made it to disk the file is full of holes. If some of the cached data was flushed to disk then it may just be a section of the file at the end that has holes. There are existing fixes to help alleviate this problem, particularly in the case where a file has been truncated, that force cached data to be flushed to disk when the file is closed. If the system crashes while the file(s) are still open then this flushing will never occur. The fix that we have implemented is to introduce a second file size, called the in-memory file size, that represents the current file size as viewed by the user. The existing file size, called the on-disk file size, is the one that get's written to the filesystem log and we only update it when it is safe to do so. When we write to a file beyond eof we only update the in- memory file size in the write operation. Later when the I/O operation, that flushes the cached data to disk completes, an I/O completion routine will update the on-disk file size. The on-disk file size will be updated to the maximum offset of the I/O or to the value of the in-memory file size if the I/O includes eof. SGI-PV: 958522 SGI-Modid: xfs-linux-melb:xfs-kern:28322a Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-08 11:49:46 +08:00
/*
* Update on-disk file size now that data has been written to disk.
[XFS] Fix to prevent the notorious 'NULL files' problem after a crash. The problem that has been addressed is that of synchronising updates of the file size with writes that extend a file. Without the fix the update of a file's size, as a result of a write beyond eof, is independent of when the cached data is flushed to disk. Often the file size update would be written to the filesystem log before the data is flushed to disk. When a system crashes between these two events and the filesystem log is replayed on mount the file's size will be set but since the contents never made it to disk the file is full of holes. If some of the cached data was flushed to disk then it may just be a section of the file at the end that has holes. There are existing fixes to help alleviate this problem, particularly in the case where a file has been truncated, that force cached data to be flushed to disk when the file is closed. If the system crashes while the file(s) are still open then this flushing will never occur. The fix that we have implemented is to introduce a second file size, called the in-memory file size, that represents the current file size as viewed by the user. The existing file size, called the on-disk file size, is the one that get's written to the filesystem log and we only update it when it is safe to do so. When we write to a file beyond eof we only update the in- memory file size in the write operation. Later when the I/O operation, that flushes the cached data to disk completes, an I/O completion routine will update the on-disk file size. The on-disk file size will be updated to the maximum offset of the I/O or to the value of the in-memory file size if the I/O includes eof. SGI-PV: 958522 SGI-Modid: xfs-linux-melb:xfs-kern:28322a Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-08 11:49:46 +08:00
*/
STATIC int
__xfs_setfilesize(
struct xfs_inode *ip,
struct xfs_trans *tp,
xfs_off_t offset,
size_t size)
[XFS] Fix to prevent the notorious 'NULL files' problem after a crash. The problem that has been addressed is that of synchronising updates of the file size with writes that extend a file. Without the fix the update of a file's size, as a result of a write beyond eof, is independent of when the cached data is flushed to disk. Often the file size update would be written to the filesystem log before the data is flushed to disk. When a system crashes between these two events and the filesystem log is replayed on mount the file's size will be set but since the contents never made it to disk the file is full of holes. If some of the cached data was flushed to disk then it may just be a section of the file at the end that has holes. There are existing fixes to help alleviate this problem, particularly in the case where a file has been truncated, that force cached data to be flushed to disk when the file is closed. If the system crashes while the file(s) are still open then this flushing will never occur. The fix that we have implemented is to introduce a second file size, called the in-memory file size, that represents the current file size as viewed by the user. The existing file size, called the on-disk file size, is the one that get's written to the filesystem log and we only update it when it is safe to do so. When we write to a file beyond eof we only update the in- memory file size in the write operation. Later when the I/O operation, that flushes the cached data to disk completes, an I/O completion routine will update the on-disk file size. The on-disk file size will be updated to the maximum offset of the I/O or to the value of the in-memory file size if the I/O includes eof. SGI-PV: 958522 SGI-Modid: xfs-linux-melb:xfs-kern:28322a Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-08 11:49:46 +08:00
{
xfs_fsize_t isize;
xfs_ilock(ip, XFS_ILOCK_EXCL);
isize = xfs_new_eof(ip, offset + size);
if (!isize) {
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_trans_cancel(tp);
return 0;
[XFS] Fix to prevent the notorious 'NULL files' problem after a crash. The problem that has been addressed is that of synchronising updates of the file size with writes that extend a file. Without the fix the update of a file's size, as a result of a write beyond eof, is independent of when the cached data is flushed to disk. Often the file size update would be written to the filesystem log before the data is flushed to disk. When a system crashes between these two events and the filesystem log is replayed on mount the file's size will be set but since the contents never made it to disk the file is full of holes. If some of the cached data was flushed to disk then it may just be a section of the file at the end that has holes. There are existing fixes to help alleviate this problem, particularly in the case where a file has been truncated, that force cached data to be flushed to disk when the file is closed. If the system crashes while the file(s) are still open then this flushing will never occur. The fix that we have implemented is to introduce a second file size, called the in-memory file size, that represents the current file size as viewed by the user. The existing file size, called the on-disk file size, is the one that get's written to the filesystem log and we only update it when it is safe to do so. When we write to a file beyond eof we only update the in- memory file size in the write operation. Later when the I/O operation, that flushes the cached data to disk completes, an I/O completion routine will update the on-disk file size. The on-disk file size will be updated to the maximum offset of the I/O or to the value of the in-memory file size if the I/O includes eof. SGI-PV: 958522 SGI-Modid: xfs-linux-melb:xfs-kern:28322a Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-08 11:49:46 +08:00
}
trace_xfs_setfilesize(ip, offset, size);
ip->i_d.di_size = isize;
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
return xfs_trans_commit(tp);
}
int
xfs_setfilesize(
struct xfs_inode *ip,
xfs_off_t offset,
size_t size)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
if (error)
return error;
return __xfs_setfilesize(ip, tp, offset, size);
}
STATIC int
xfs_setfilesize_ioend(
struct xfs_ioend *ioend,
int error)
{
struct xfs_inode *ip = XFS_I(ioend->io_inode);
struct xfs_trans *tp = ioend->io_append_trans;
/*
* The transaction may have been allocated in the I/O submission thread,
* thus we need to mark ourselves as being in a transaction manually.
* Similarly for freeze protection.
*/
current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
__sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
/* we abort the update if there was an IO error */
if (error) {
xfs_trans_cancel(tp);
return error;
}
return __xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
}
/*
* IO write completion.
*/
STATIC void
xfs_end_io(
struct work_struct *work)
{
struct xfs_ioend *ioend =
container_of(work, struct xfs_ioend, io_work);
struct xfs_inode *ip = XFS_I(ioend->io_inode);
xfs_off_t offset = ioend->io_offset;
size_t size = ioend->io_size;
int error;
[XFS] Fix to prevent the notorious 'NULL files' problem after a crash. The problem that has been addressed is that of synchronising updates of the file size with writes that extend a file. Without the fix the update of a file's size, as a result of a write beyond eof, is independent of when the cached data is flushed to disk. Often the file size update would be written to the filesystem log before the data is flushed to disk. When a system crashes between these two events and the filesystem log is replayed on mount the file's size will be set but since the contents never made it to disk the file is full of holes. If some of the cached data was flushed to disk then it may just be a section of the file at the end that has holes. There are existing fixes to help alleviate this problem, particularly in the case where a file has been truncated, that force cached data to be flushed to disk when the file is closed. If the system crashes while the file(s) are still open then this flushing will never occur. The fix that we have implemented is to introduce a second file size, called the in-memory file size, that represents the current file size as viewed by the user. The existing file size, called the on-disk file size, is the one that get's written to the filesystem log and we only update it when it is safe to do so. When we write to a file beyond eof we only update the in- memory file size in the write operation. Later when the I/O operation, that flushes the cached data to disk completes, an I/O completion routine will update the on-disk file size. The on-disk file size will be updated to the maximum offset of the I/O or to the value of the in-memory file size if the I/O includes eof. SGI-PV: 958522 SGI-Modid: xfs-linux-melb:xfs-kern:28322a Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-08 11:49:46 +08:00
/*
* Just clean up the in-memory strutures if the fs has been shut down.
*/
if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
error = -EIO;
goto done;
}
/*
* Clean up any COW blocks on an I/O error.
*/
error = blk_status_to_errno(ioend->io_bio->bi_status);
if (unlikely(error)) {
switch (ioend->io_type) {
case XFS_IO_COW:
xfs_reflink_cancel_cow_range(ip, offset, size, true);
break;
}
goto done;
}
/*
* Success: commit the COW or unwritten blocks if needed.
*/
switch (ioend->io_type) {
case XFS_IO_COW:
error = xfs_reflink_end_cow(ip, offset, size);
break;
case XFS_IO_UNWRITTEN:
/* writeback should never update isize */
error = xfs_iomap_write_unwritten(ip, offset, size, false);
break;
default:
ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
break;
}
[XFS] Fix to prevent the notorious 'NULL files' problem after a crash. The problem that has been addressed is that of synchronising updates of the file size with writes that extend a file. Without the fix the update of a file's size, as a result of a write beyond eof, is independent of when the cached data is flushed to disk. Often the file size update would be written to the filesystem log before the data is flushed to disk. When a system crashes between these two events and the filesystem log is replayed on mount the file's size will be set but since the contents never made it to disk the file is full of holes. If some of the cached data was flushed to disk then it may just be a section of the file at the end that has holes. There are existing fixes to help alleviate this problem, particularly in the case where a file has been truncated, that force cached data to be flushed to disk when the file is closed. If the system crashes while the file(s) are still open then this flushing will never occur. The fix that we have implemented is to introduce a second file size, called the in-memory file size, that represents the current file size as viewed by the user. The existing file size, called the on-disk file size, is the one that get's written to the filesystem log and we only update it when it is safe to do so. When we write to a file beyond eof we only update the in- memory file size in the write operation. Later when the I/O operation, that flushes the cached data to disk completes, an I/O completion routine will update the on-disk file size. The on-disk file size will be updated to the maximum offset of the I/O or to the value of the in-memory file size if the I/O includes eof. SGI-PV: 958522 SGI-Modid: xfs-linux-melb:xfs-kern:28322a Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-08 11:49:46 +08:00
done:
if (ioend->io_append_trans)
error = xfs_setfilesize_ioend(ioend, error);
xfs_destroy_ioend(ioend, error);
}
STATIC void
xfs_end_bio(
struct bio *bio)
{
struct xfs_ioend *ioend = bio->bi_private;
struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
if (ioend->io_type == XFS_IO_UNWRITTEN || ioend->io_type == XFS_IO_COW)
queue_work(mp->m_unwritten_workqueue, &ioend->io_work);
else if (ioend->io_append_trans)
queue_work(mp->m_data_workqueue, &ioend->io_work);
else
xfs_destroy_ioend(ioend, blk_status_to_errno(bio->bi_status));
}
STATIC int
xfs_map_blocks(
struct inode *inode,
loff_t offset,
struct xfs_bmbt_irec *imap,
int type)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t count = i_blocksize(inode);
xfs_fileoff_t offset_fsb, end_fsb;
int error = 0;
int bmapi_flags = XFS_BMAPI_ENTIRE;
int nimaps = 1;
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
ASSERT(type != XFS_IO_COW);
if (type == XFS_IO_UNWRITTEN)
bmapi_flags |= XFS_BMAPI_IGSTATE;
xfs_ilock(ip, XFS_ILOCK_SHARED);
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
(ip->i_df.if_flags & XFS_IFEXTENTS));
ASSERT(offset <= mp->m_super->s_maxbytes);
if ((xfs_ufsize_t)offset + count > mp->m_super->s_maxbytes)
count = mp->m_super->s_maxbytes - offset;
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
imap, &nimaps, bmapi_flags);
/*
* Truncate an overwrite extent if there's a pending CoW
* reservation before the end of this extent. This forces us
* to come back to writepage to take care of the CoW.
*/
if (nimaps && type == XFS_IO_OVERWRITE)
xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error)
return error;
if (type == XFS_IO_DELALLOC &&
(!nimaps || isnullstartblock(imap->br_startblock))) {
error = xfs_iomap_write_allocate(ip, XFS_DATA_FORK, offset,
imap);
if (!error)
trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
return error;
}
#ifdef DEBUG
if (type == XFS_IO_UNWRITTEN) {
ASSERT(nimaps);
ASSERT(imap->br_startblock != HOLESTARTBLOCK);
ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
}
#endif
if (nimaps)
trace_xfs_map_blocks_found(ip, offset, count, type, imap);
return 0;
}
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
STATIC bool
xfs_imap_valid(
struct inode *inode,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
offset >>= inode->i_blkbits;
xfs: trim writepage mapping to within eof The writeback rework in commit fbcc02561359 ("xfs: Introduce writeback context for writepages") introduced a subtle change in behavior with regard to the block mapping used across the ->writepages() sequence. The previous xfs_cluster_write() code would only flush pages up to EOF at the time of the writepage, thus ensuring that any pages due to file-extending writes would be handled on a separate cycle and with a new, updated block mapping. The updated code establishes a block mapping in xfs_writepage_map() that could extend beyond EOF if the file has post-eof preallocation. Because we now use the generic writeback infrastructure and pass the cached mapping to each writepage call, there is no implicit EOF limit in place. If eofblocks trimming occurs during ->writepages(), any post-eof portion of the cached mapping becomes invalid. The eofblocks code has no means to serialize against writeback because there are no pages associated with post-eof blocks. Therefore if an eofblocks trim occurs and is followed by a file-extending buffered write, not only has the mapping become invalid, but we could end up writing a page to disk based on the invalid mapping. Consider the following sequence of events: - A buffered write creates a delalloc extent and post-eof speculative preallocation. - Writeback starts and on the first writepage cycle, the delalloc extent is converted to real blocks (including the post-eof blocks) and the mapping is cached. - The file is closed and xfs_release() trims post-eof blocks. The cached writeback mapping is now invalid. - Another buffered write appends the file with a delalloc extent. - The concurrent writeback cycle picks up the just written page because the writeback range end is LLONG_MAX. xfs_writepage_map() attributes it to the (now invalid) cached mapping and writes the data to an incorrect location on disk (and where the file offset is still backed by a delalloc extent). This problem is reproduced by xfstests test generic/464, which triggers racing writes, appends, open/closes and writeback requests. To address this problem, trim the mapping used during writeback to within EOF when the mapping is validated. This ensures the mapping is revalidated for any pages encountered beyond EOF as of the time the current mapping was cached or last validated. Reported-by: Eryu Guan <eguan@redhat.com> Diagnosed-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:46 +08:00
/*
* We have to make sure the cached mapping is within EOF to protect
* against eofblocks trimming on file release leaving us with a stale
* mapping. Otherwise, a page for a subsequent file extending buffered
* write could get picked up by this writeback cycle and written to the
* wrong blocks.
*
* Note that what we really want here is a generic mapping invalidation
* mechanism to protect us from arbitrary extent modifying contexts, not
* just eofblocks.
*/
xfs_trim_extent_eof(imap, XFS_I(inode));
return offset >= imap->br_startoff &&
offset < imap->br_startoff + imap->br_blockcount;
}
STATIC void
xfs_start_buffer_writeback(
struct buffer_head *bh)
{
ASSERT(buffer_mapped(bh));
ASSERT(buffer_locked(bh));
ASSERT(!buffer_delay(bh));
ASSERT(!buffer_unwritten(bh));
bh->b_end_io = NULL;
set_buffer_async_write(bh);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
}
STATIC void
xfs_start_page_writeback(
struct page *page,
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
int clear_dirty)
{
ASSERT(PageLocked(page));
ASSERT(!PageWriteback(page));
xfs: ensure WB_SYNC_ALL writeback handles partial pages correctly XFS has been having trouble with stray delayed allocation extents beyond EOF for a long time. Recent changes to the collapse range code has triggered erroneous EBUSY errors on page invalidtion for block size smaller than page size filesystems. These have been caused by dirty buffers beyond EOF on a partial page which do not get written to disk during a sync. The issue is that write-ahead in xfs_cluster_write() finds such a partial page and handles it by leaving the page dirty but pushing it into a writeback state. This used to work just fine, as the write_cache_pages() code would then find the dirty partial page in the next mapping tree lookup as the dirty tag is still set. Unfortunately, when we moved to a mark and sweep approach to writeback to fix other writeback sync issues, we broken this. THe act of marking the page as under writeback now clears the TOWRITE tag in the radix tree, even though the page is still dirty. This causes the TOWRITE tag to be cleared, and hence the next lookup on the mapping tree does not find the dirty partial page and so doesn't try to write it again. This same writeback bug was found recently in ext4 and fixed in commit 1c8349a ("ext4: fix data integrity sync in ordered mode") without communication to the wider filesystem community. We can use exactly the same fix here so the TOWRITE flag is not cleared on partial page writes. cc: stable@vger.kernel.org # dependent on 1c8349a17137b93f0a83f276c764a6df1b9a116e Root-cause-found-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-23 13:36:27 +08:00
/*
* if the page was not fully cleaned, we need to ensure that the higher
* layers come back to it correctly. That means we need to keep the page
* dirty, and for WB_SYNC_ALL writeback we need to ensure the
* PAGECACHE_TAG_TOWRITE index mark is not removed so another attempt to
* write this page in this writeback sweep will be made.
*/
if (clear_dirty) {
clear_page_dirty_for_io(page);
xfs: ensure WB_SYNC_ALL writeback handles partial pages correctly XFS has been having trouble with stray delayed allocation extents beyond EOF for a long time. Recent changes to the collapse range code has triggered erroneous EBUSY errors on page invalidtion for block size smaller than page size filesystems. These have been caused by dirty buffers beyond EOF on a partial page which do not get written to disk during a sync. The issue is that write-ahead in xfs_cluster_write() finds such a partial page and handles it by leaving the page dirty but pushing it into a writeback state. This used to work just fine, as the write_cache_pages() code would then find the dirty partial page in the next mapping tree lookup as the dirty tag is still set. Unfortunately, when we moved to a mark and sweep approach to writeback to fix other writeback sync issues, we broken this. THe act of marking the page as under writeback now clears the TOWRITE tag in the radix tree, even though the page is still dirty. This causes the TOWRITE tag to be cleared, and hence the next lookup on the mapping tree does not find the dirty partial page and so doesn't try to write it again. This same writeback bug was found recently in ext4 and fixed in commit 1c8349a ("ext4: fix data integrity sync in ordered mode") without communication to the wider filesystem community. We can use exactly the same fix here so the TOWRITE flag is not cleared on partial page writes. cc: stable@vger.kernel.org # dependent on 1c8349a17137b93f0a83f276c764a6df1b9a116e Root-cause-found-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-23 13:36:27 +08:00
set_page_writeback(page);
} else
set_page_writeback_keepwrite(page);
unlock_page(page);
}
static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh)
{
return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
}
/*
* Submit the bio for an ioend. We are passed an ioend with a bio attached to
* it, and we submit that bio. The ioend may be used for multiple bio
* submissions, so we only want to allocate an append transaction for the ioend
* once. In the case of multiple bio submission, each bio will take an IO
* reference to the ioend to ensure that the ioend completion is only done once
* all bios have been submitted and the ioend is really done.
xfs: fix broken error handling in xfs_vm_writepage When we shut down the filesystem, it might first be detected in writeback when we are allocating a inode size transaction. This happens after we have moved all the pages into the writeback state and unlocked them. Unfortunately, if we fail to set up the transaction we then abort writeback and try to invalidate the current page. This then triggers are BUG() in block_invalidatepage() because we are trying to invalidate an unlocked page. Fixing this is a bit of a chicken and egg problem - we can't allocate the transaction until we've clustered all the pages into the IO and we know the size of it (i.e. whether the last block of the IO is beyond the current EOF or not). However, we don't want to hold pages locked for long periods of time, especially while we lock other pages to cluster them into the write. To fix this, we need to make a clear delineation in writeback where errors can only be handled by IO completion processing. That is, once we have marked a page for writeback and unlocked it, we have to report errors via IO completion because we've already started the IO. We may not have submitted any IO, but we've changed the page state to indicate that it is under IO so we must now use the IO completion path to report errors. To do this, add an error field to xfs_submit_ioend() to pass it the error that occurred during the building on the ioend chain. When this is non-zero, mark each ioend with the error and call xfs_finish_ioend() directly rather than building bios. This will immediately push the ioends through completion processing with the error that has occurred. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-12 19:09:45 +08:00
*
* If @fail is non-zero, it means that we have a situation where some part of
* the submission process has failed after we have marked paged for writeback
* and unlocked them. In this situation, we need to fail the bio and ioend
* rather than submit it to IO. This typically only happens on a filesystem
* shutdown.
*/
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
STATIC int
xfs_submit_ioend(
struct writeback_control *wbc,
struct xfs_ioend *ioend,
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
int status)
{
xfs: mark speculative prealloc CoW fork extents unwritten Christoph Hellwig pointed out that there's a potentially nasty race when performing simultaneous nearby directio cow writes: "Thread 1 writes a range from B to c " B --------- C p "a little later thread 2 writes from A to B " A --------- B p [editor's note: the 'p' denote cowextsize boundaries, which I added to make this more clear] "but the code preallocates beyond B into the range where thread "1 has just written, but ->end_io hasn't been called yet. "But once ->end_io is called thread 2 has already allocated "up to the extent size hint into the write range of thread 1, "so the end_io handler will splice the unintialized blocks from "that preallocation back into the file right after B." We can avoid this race by ensuring that thread 1 cannot accidentally remap the blocks that thread 2 allocated (as part of speculative preallocation) as part of t2's write preparation in t1's end_io handler. The way we make this happen is by taking advantage of the unwritten extent flag as an intermediate step. Recall that when we begin the process of writing data to shared blocks, we create a delayed allocation extent in the CoW fork: D: --RRRRRRSSSRRRRRRRR--- C: ------DDDDDDD--------- When a thread prepares to CoW some dirty data out to disk, it will now convert the delalloc reservation into an /unwritten/ allocated extent in the cow fork. The da conversion code tries to opportunistically allocate as much of a (speculatively prealloc'd) extent as possible, so we may end up allocating a larger extent than we're actually writing out: D: --RRRRRRSSSRRRRRRRR--- U: ------UUUUUUU--------- Next, we convert only the part of the extent that we're actively planning to write to normal (i.e. not unwritten) status: D: --RRRRRRSSSRRRRRRRR--- U: ------UURRUUU--------- If the write succeeds, the end_cow function will now scan the relevant range of the CoW fork for real extents and remap only the real extents into the data fork: D: --RRRRRRRRSRRRRRRRR--- U: ------UU--UUU--------- This ensures that we never obliterate valid data fork extents with unwritten blocks from the CoW fork. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-02-03 07:14:02 +08:00
/* Convert CoW extents to regular */
if (!status && ioend->io_type == XFS_IO_COW) {
status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
ioend->io_offset, ioend->io_size);
}
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
/* Reserve log space if we might write beyond the on-disk inode size. */
if (!status &&
ioend->io_type != XFS_IO_UNWRITTEN &&
xfs_ioend_is_append(ioend) &&
!ioend->io_append_trans)
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
status = xfs_setfilesize_trans_alloc(ioend);
ioend->io_bio->bi_private = ioend;
ioend->io_bio->bi_end_io = xfs_end_bio;
ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
/*
* If we are failing the IO now, just mark the ioend with an
* error and finish it. This will run IO completion immediately
* as there is only one reference to the ioend at this point in
* time.
*/
if (status) {
ioend->io_bio->bi_status = errno_to_blk_status(status);
bio_endio(ioend->io_bio);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
return status;
}
ioend->io_bio->bi_write_hint = ioend->io_inode->i_write_hint;
submit_bio(ioend->io_bio);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
return 0;
}
static void
xfs_init_bio_from_bh(
struct bio *bio,
struct buffer_head *bh)
{
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio_set_dev(bio, bh->b_bdev);
}
xfs: fix broken error handling in xfs_vm_writepage When we shut down the filesystem, it might first be detected in writeback when we are allocating a inode size transaction. This happens after we have moved all the pages into the writeback state and unlocked them. Unfortunately, if we fail to set up the transaction we then abort writeback and try to invalidate the current page. This then triggers are BUG() in block_invalidatepage() because we are trying to invalidate an unlocked page. Fixing this is a bit of a chicken and egg problem - we can't allocate the transaction until we've clustered all the pages into the IO and we know the size of it (i.e. whether the last block of the IO is beyond the current EOF or not). However, we don't want to hold pages locked for long periods of time, especially while we lock other pages to cluster them into the write. To fix this, we need to make a clear delineation in writeback where errors can only be handled by IO completion processing. That is, once we have marked a page for writeback and unlocked it, we have to report errors via IO completion because we've already started the IO. We may not have submitted any IO, but we've changed the page state to indicate that it is under IO so we must now use the IO completion path to report errors. To do this, add an error field to xfs_submit_ioend() to pass it the error that occurred during the building on the ioend chain. When this is non-zero, mark each ioend with the error and call xfs_finish_ioend() directly rather than building bios. This will immediately push the ioends through completion processing with the error that has occurred. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-12 19:09:45 +08:00
static struct xfs_ioend *
xfs_alloc_ioend(
struct inode *inode,
unsigned int type,
xfs_off_t offset,
struct buffer_head *bh)
{
struct xfs_ioend *ioend;
struct bio *bio;
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, xfs_ioend_bioset);
xfs_init_bio_from_bh(bio, bh);
ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
INIT_LIST_HEAD(&ioend->io_list);
ioend->io_type = type;
ioend->io_inode = inode;
ioend->io_size = 0;
ioend->io_offset = offset;
INIT_WORK(&ioend->io_work, xfs_end_io);
ioend->io_append_trans = NULL;
ioend->io_bio = bio;
return ioend;
}
/*
* Allocate a new bio, and chain the old bio to the new one.
*
* Note that we have to do perform the chaining in this unintuitive order
* so that the bi_private linkage is set up in the right direction for the
* traversal in xfs_destroy_ioend().
*/
static void
xfs_chain_bio(
struct xfs_ioend *ioend,
struct writeback_control *wbc,
struct buffer_head *bh)
{
struct bio *new;
new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
xfs_init_bio_from_bh(new, bh);
bio_chain(ioend->io_bio, new);
bio_get(ioend->io_bio); /* for xfs_destroy_ioend */
ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
ioend->io_bio->bi_write_hint = ioend->io_inode->i_write_hint;
submit_bio(ioend->io_bio);
ioend->io_bio = new;
}
/*
* Test to see if we've been building up a completion structure for
* earlier buffers -- if so, we try to append to this ioend if we
* can, otherwise we finish off any current ioend and start another.
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
* Return the ioend we finished off so that the caller can submit it
* once it has finished processing the dirty page.
*/
STATIC void
xfs_add_to_ioend(
struct inode *inode,
struct buffer_head *bh,
xfs_off_t offset,
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
struct xfs_writepage_ctx *wpc,
struct writeback_control *wbc,
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
struct list_head *iolist)
{
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
bh->b_blocknr != wpc->last_block + 1 ||
offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
if (wpc->ioend)
list_add(&wpc->ioend->io_list, iolist);
wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset, bh);
}
/*
* If the buffer doesn't fit into the bio we need to allocate a new
* one. This shouldn't happen more than once for a given buffer.
*/
while (xfs_bio_add_buffer(wpc->ioend->io_bio, bh) != bh->b_size)
xfs_chain_bio(wpc->ioend, wbc, bh);
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
wpc->ioend->io_size += bh->b_size;
wpc->last_block = bh->b_blocknr;
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
xfs_start_buffer_writeback(bh);
}
STATIC void
xfs_map_buffer(
struct inode *inode,
struct buffer_head *bh,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
sector_t bn;
struct xfs_mount *m = XFS_I(inode)->i_mount;
xfs_off_t iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
xfs_daddr_t iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
ASSERT(imap->br_startblock != HOLESTARTBLOCK);
ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
((offset - iomap_offset) >> inode->i_blkbits);
ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode)));
bh->b_blocknr = bn;
set_buffer_mapped(bh);
}
STATIC void
xfs_map_at_offset(
struct inode *inode,
struct buffer_head *bh,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
ASSERT(imap->br_startblock != HOLESTARTBLOCK);
ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
xfs_map_buffer(inode, bh, imap, offset);
set_buffer_mapped(bh);
clear_buffer_delay(bh);
clear_buffer_unwritten(bh);
}
/*
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
* Test if a given page contains at least one buffer of a given @type.
* If @check_all_buffers is true, then we walk all the buffers in the page to
* try to find one of the type passed in. If it is not set, then the caller only
* needs to check the first buffer on the page for a match.
*/
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
STATIC bool
xfs_check_page_type(
struct page *page,
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
unsigned int type,
bool check_all_buffers)
{
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
struct buffer_head *bh;
struct buffer_head *head;
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
if (PageWriteback(page))
return false;
if (!page->mapping)
return false;
if (!page_has_buffers(page))
return false;
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
bh = head = page_buffers(page);
do {
if (buffer_unwritten(bh)) {
if (type == XFS_IO_UNWRITTEN)
return true;
} else if (buffer_delay(bh)) {
if (type == XFS_IO_DELALLOC)
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
return true;
} else if (buffer_dirty(bh) && buffer_mapped(bh)) {
if (type == XFS_IO_OVERWRITE)
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
return true;
}
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
/* If we are only checking the first buffer, we are done now. */
if (!check_all_buffers)
break;
} while ((bh = bh->b_this_page) != head);
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
return false;
}
STATIC void
xfs_vm_invalidatepage(
struct page *page,
unsigned int offset,
unsigned int length)
{
trace_xfs_invalidatepage(page->mapping->host, page, offset,
length);
xfs: cancel dirty pages on invalidation Recently we've had warnings arise from the vm handing us pages without bufferheads attached to them. This should not ever occur in XFS, but we don't defend against it properly if it does. The only place where we remove bufferheads from a page is in xfs_vm_releasepage(), but we can't tell the difference here between "page is dirty so don't release" and "page is dirty but is being invalidated so release it". In some places that are invalidating pages ask for pages to be released and follow up afterward calling ->releasepage by checking whether the page was dirty and then aborting the invalidation. This is a possible vector for releasing buffers from a page but then leaving it in the mapping, so we really do need to avoid dirty pages in xfs_vm_releasepage(). To differentiate between invalidated pages and normal pages, we need to clear the page dirty flag when invalidating the pages. This can be done through xfs_vm_invalidatepage(), and will result xfs_vm_releasepage() seeing the page as clean which matches the bufferhead state on the page after calling block_invalidatepage(). Hence we can re-add the page dirty check in xfs_vm_releasepage to catch the case where we might be releasing a page that is actually dirty and so should not have the bufferheads on it removed. This will remove one possible vector of "dirty page with no bufferheads" and so help narrow down the search for the root cause of that problem. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:45 +08:00
/*
* If we are invalidating the entire page, clear the dirty state from it
* so that we can check for attempts to release dirty cached pages in
* xfs_vm_releasepage().
*/
if (offset == 0 && length >= PAGE_SIZE)
cancel_dirty_page(page);
block_invalidatepage(page, offset, length);
}
/*
* If the page has delalloc buffers on it, we need to punch them out before we
* invalidate the page. If we don't, we leave a stale delalloc mapping on the
* inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read
* is done on that same region - the delalloc extent is returned when none is
* supposed to be there.
*
* We prevent this by truncating away the delalloc regions on the page before
* invalidating it. Because they are delalloc, we can do this without needing a
* transaction. Indeed - if we get ENOSPC errors, we have to be able to do this
* truncation without a transaction as there is no space left for block
* reservation (typically why we see a ENOSPC in writeback).
*
* This is not a performance critical path, so for now just do the punching a
* buffer head at a time.
*/
STATIC void
xfs_aops_discard_page(
struct page *page)
{
struct inode *inode = page->mapping->host;
struct xfs_inode *ip = XFS_I(inode);
struct buffer_head *bh, *head;
loff_t offset = page_offset(page);
xfs: xfs_check_page_type buffer checks need help xfs_aops_discard_page() was introduced in the following commit: xfs: truncate delalloc extents when IO fails in writeback ... to clean up left over delalloc ranges after I/O failure in ->writepage(). generic/224 tests for this scenario and occasionally reproduces panics on sub-4k blocksize filesystems. The cause of this is failure to clean up the delalloc range on a page where the first buffer does not match one of the expected states of xfs_check_page_type(). If a buffer is not unwritten, delayed or dirty&mapped, xfs_check_page_type() stops and immediately returns 0. The stress test of generic/224 creates a scenario where the first several buffers of a page with delayed buffers are mapped & uptodate and some subsequent buffer is delayed. If the ->writepage() happens to fail for this page, xfs_aops_discard_page() incorrectly skips the entire page. This then causes later failures either when direct IO maps the range and finds the stale delayed buffer, or we evict the inode and find that the inode still has a delayed block reservation accounted to it. We can easily fix this xfs_aops_discard_page() failure by making xfs_check_page_type() check all buffers, but this breaks xfs_convert_page() more than it is already broken. Indeed, xfs_convert_page() wants xfs_check_page_type() to tell it if the first buffers on the pages are of a type that can be aggregated into the contiguous IO that is already being built. xfs_convert_page() should not be writing random buffers out of a page, but the current behaviour will cause it to do so if there are buffers that don't match the current specification on the page. Hence for xfs_convert_page() we need to: a) return "not ok" if the first buffer on the page does not match the specification provided to we don't write anything; and b) abort it's buffer-add-to-io loop the moment we come across a buffer that does not match the specification. Hence we need to fix both xfs_check_page_type() and xfs_convert_page() to work correctly with pages that have mixed buffer types, whilst allowing xfs_aops_discard_page() to scan all buffers on the page for a type match. Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 13:19:14 +08:00
if (!xfs_check_page_type(page, XFS_IO_DELALLOC, true))
goto out_invalidate;
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
goto out_invalidate;
xfs_alert(ip->i_mount,
"page discard on page %p, inode 0x%llx, offset %llu.",
page, ip->i_ino, offset);
xfs_ilock(ip, XFS_ILOCK_EXCL);
bh = head = page_buffers(page);
do {
int error;
xfs_fileoff_t start_fsb;
if (!buffer_delay(bh))
goto next_buffer;
start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1);
if (error) {
/* something screwed, just bail */
if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
xfs_alert(ip->i_mount,
"page discard unable to remove delalloc mapping.");
}
break;
}
next_buffer:
offset += i_blocksize(inode);
} while ((bh = bh->b_this_page) != head);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out_invalidate:
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
xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
return;
}
static int
xfs_map_cow(
struct xfs_writepage_ctx *wpc,
struct inode *inode,
loff_t offset,
unsigned int *new_type)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_bmbt_irec imap;
bool is_cow = false;
int error;
/*
* If we already have a valid COW mapping keep using it.
*/
if (wpc->io_type == XFS_IO_COW) {
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, offset);
if (wpc->imap_valid) {
*new_type = XFS_IO_COW;
return 0;
}
}
/*
* Else we need to check if there is a COW mapping at this offset.
*/
xfs_ilock(ip, XFS_ILOCK_SHARED);
is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (!is_cow)
return 0;
/*
* And if the COW mapping has a delayed extent here we need to
* allocate real space for it now.
*/
if (isnullstartblock(imap.br_startblock)) {
error = xfs_iomap_write_allocate(ip, XFS_COW_FORK, offset,
&imap);
if (error)
return error;
}
wpc->io_type = *new_type = XFS_IO_COW;
wpc->imap_valid = true;
wpc->imap = imap;
return 0;
}
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
/*
* We implement an immediate ioend submission policy here to avoid needing to
* chain multiple ioends and hence nest mempool allocations which can violate
* forward progress guarantees we need to provide. The current ioend we are
* adding buffers to is cached on the writepage context, and if the new buffer
* does not append to the cached ioend it will create a new ioend and cache that
* instead.
*
* If a new ioend is created and cached, the old ioend is returned and queued
* locally for submission once the entire page is processed or an error has been
* detected. While ioends are submitted immediately after they are completed,
* batching optimisations are provided by higher level block plugging.
*
* At the end of a writeback pass, there will be a cached ioend remaining on the
* writepage context that the caller will need to submit.
*/
static int
xfs_writepage_map(
struct xfs_writepage_ctx *wpc,
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
struct writeback_control *wbc,
struct inode *inode,
struct page *page,
uint64_t end_offset)
{
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
LIST_HEAD(submit_list);
struct xfs_ioend *ioend, *next;
struct buffer_head *bh, *head;
ssize_t len = i_blocksize(inode);
uint64_t offset;
int error = 0;
int count = 0;
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
int uptodate = 1;
unsigned int new_type;
bh = head = page_buffers(page);
offset = page_offset(page);
do {
if (offset >= end_offset)
break;
if (!buffer_uptodate(bh))
uptodate = 0;
/*
* set_page_dirty dirties all buffers in a page, independent
* of their state. The dirty state however is entirely
* meaningless for holes (!mapped && uptodate), so skip
* buffers covering holes here.
*/
if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
wpc->imap_valid = false;
continue;
}
if (buffer_unwritten(bh))
new_type = XFS_IO_UNWRITTEN;
else if (buffer_delay(bh))
new_type = XFS_IO_DELALLOC;
else if (buffer_uptodate(bh))
new_type = XFS_IO_OVERWRITE;
else {
if (PageUptodate(page))
ASSERT(buffer_mapped(bh));
/*
* This buffer is not uptodate and will not be
* written to disk. Ensure that we will put any
* subsequent writeable buffers into a new
* ioend.
*/
wpc->imap_valid = false;
continue;
}
if (xfs_is_reflink_inode(XFS_I(inode))) {
error = xfs_map_cow(wpc, inode, offset, &new_type);
if (error)
goto out;
}
if (wpc->io_type != new_type) {
wpc->io_type = new_type;
wpc->imap_valid = false;
}
if (wpc->imap_valid)
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
offset);
if (!wpc->imap_valid) {
error = xfs_map_blocks(inode, offset, &wpc->imap,
wpc->io_type);
if (error)
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
goto out;
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
offset);
}
if (wpc->imap_valid) {
lock_buffer(bh);
if (wpc->io_type != XFS_IO_OVERWRITE)
xfs_map_at_offset(inode, bh, &wpc->imap, offset);
xfs_add_to_ioend(inode, bh, offset, wpc, wbc, &submit_list);
count++;
}
} while (offset += len, ((bh = bh->b_this_page) != head));
if (uptodate && bh == head)
SetPageUptodate(page);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
ASSERT(wpc->ioend || list_empty(&submit_list));
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
out:
/*
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
* On error, we have to fail the ioend here because we have locked
* buffers in the ioend. If we don't do this, we'll deadlock
* invalidating the page as that tries to lock the buffers on the page.
* Also, because we may have set pages under writeback, we have to make
* sure we run IO completion to mark the error state of the IO
* appropriately, so we can't cancel the ioend directly here. That means
* we have to mark this page as under writeback if we included any
* buffers from it in the ioend chain so that completion treats it
* correctly.
*
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
* If we didn't include the page in the ioend, the on error we can
* simply discard and unlock it as there are no other users of the page
* or it's buffers right now. The caller will still need to trigger
* submission of outstanding ioends on the writepage context so they are
* treated correctly on error.
*/
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
if (count) {
xfs_start_page_writeback(page, !error);
/*
* Preserve the original error if there was one, otherwise catch
* submission errors here and propagate into subsequent ioend
* submissions.
*/
list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
int error2;
list_del_init(&ioend->io_list);
error2 = xfs_submit_ioend(wbc, ioend, error);
if (error2 && !error)
error = error2;
}
} else if (error) {
xfs_aops_discard_page(page);
ClearPageUptodate(page);
unlock_page(page);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
} else {
/*
* We can end up here with no error and nothing to write if we
* race with a partial page truncate on a sub-page block sized
* filesystem. In that case we need to mark the page clean.
*/
xfs_start_page_writeback(page, 1);
end_page_writeback(page);
}
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
mapping_set_error(page->mapping, error);
return error;
}
/*
* Write out a dirty page.
*
* For delalloc space on the page we need to allocate space and flush it.
* For unwritten space on the page we need to start the conversion to
* regular allocated space.
* For any other dirty buffer heads on the page we should flush them.
*/
STATIC int
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
xfs_do_writepage(
struct page *page,
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
struct writeback_control *wbc,
void *data)
{
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
struct xfs_writepage_ctx *wpc = data;
struct inode *inode = page->mapping->host;
loff_t offset;
uint64_t end_offset;
pgoff_t end_index;
trace_xfs_writepage(inode, page, 0, 0);
ASSERT(page_has_buffers(page));
/*
* Refuse to write the page out if we are called from reclaim context.
*
* This avoids stack overflows when called from deeply used stacks in
* random callers for direct reclaim or memcg reclaim. We explicitly
* allow reclaim from kswapd as the stack usage there is relatively low.
*
* This should never happen except in the case of a VM regression so
* warn about it.
*/
if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
PF_MEMALLOC))
goto redirty;
/*
* Given that we do not allow direct reclaim to call us, we should
* never be called while in a filesystem transaction.
*/
if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS))
goto redirty;
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
/*
* Is this page beyond the end of the file?
*
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
* The page index is less than the end_index, adjust the end_offset
* to the highest offset that this page should represent.
* -----------------------------------------------------
* | file mapping | <EOF> |
* -----------------------------------------------------
* | Page ... | Page N-2 | Page N-1 | Page N | |
* ^--------------------------------^----------|--------
* | desired writeback range | see else |
* ---------------------------------^------------------|
*/
offset = i_size_read(inode);
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
end_index = offset >> PAGE_SHIFT;
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
if (page->index < end_index)
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
end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
else {
/*
* Check whether the page to write out is beyond or straddles
* i_size or not.
* -------------------------------------------------------
* | file mapping | <EOF> |
* -------------------------------------------------------
* | Page ... | Page N-2 | Page N-1 | Page N | Beyond |
* ^--------------------------------^-----------|---------
* | | Straddles |
* ---------------------------------^-----------|--------|
*/
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 offset_into_page = offset & (PAGE_SIZE - 1);
/*
* Skip the page if it is fully outside i_size, e.g. due to a
* truncate operation that is in progress. We must redirty the
* page so that reclaim stops reclaiming it. Otherwise
* xfs_vm_releasepage() is called on it and gets confused.
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
*
* Note that the end_index is unsigned long, it would overflow
* if the given offset is greater than 16TB on 32-bit system
* and if we do check the page is fully outside i_size or not
* via "if (page->index >= end_index + 1)" as "end_index + 1"
* will be evaluated to 0. Hence this page will be redirtied
* and be written out repeatedly which would result in an
* infinite loop, the user program that perform this operation
* will hang. Instead, we can verify this situation by checking
* if the page to write is totally beyond the i_size or if it's
* offset is just equal to the EOF.
*/
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
if (page->index > end_index ||
(page->index == end_index && offset_into_page == 0))
goto redirty;
/*
* The page straddles i_size. It must be zeroed out on each
* and every writepage invocation because it may be mmapped.
* "A file is mapped in multiples of the page size. For a file
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
* that is not a multiple of the page size, the remaining
* memory is zeroed when mapped, and writes to that region are
* not written out to the file."
*/
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
zero_user_segment(page, offset_into_page, PAGE_SIZE);
xfs: fix infinite loop at xfs_vm_writepage on 32bit system Write to a file with an offset greater than 16TB on 32-bit system and then trigger page write-back via sync(1) will cause task hang. # block_size=4096 # offset=$(((2**32 - 1) * $block_size)) # xfs_io -f -c "pwrite $offset $block_size" /storage/test_file # sync INFO: task sync:2590 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sync D c1064a28 0 2590 2097 0x00000000 ..... Call Trace: [<c1064a28>] ? ttwu_do_wakeup+0x18/0x130 [<c1066d0e>] ? try_to_wake_up+0x1ce/0x220 [<c1066dbf>] ? wake_up_process+0x1f/0x40 [<c104fc2e>] ? wake_up_worker+0x1e/0x30 [<c15b6083>] schedule+0x23/0x60 [<c15b3c2d>] schedule_timeout+0x18d/0x1f0 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c10515f1>] ? __queue_delayed_work+0x91/0x150 [<c12a12ef>] ? do_raw_spin_lock+0x3f/0x100 [<c12a143e>] ? do_raw_spin_unlock+0x4e/0x90 [<c15b5b5d>] wait_for_completion+0x7d/0xc0 [<c1066d60>] ? try_to_wake_up+0x220/0x220 [<c116a4d2>] sync_inodes_sb+0x92/0x180 [<c116fb05>] sync_inodes_one_sb+0x15/0x20 [<c114a8f8>] iterate_supers+0xb8/0xc0 [<c116faf0>] ? fdatawrite_one_bdev+0x20/0x20 [<c116fc21>] sys_sync+0x31/0x80 [<c15be18d>] sysenter_do_call+0x12/0x28 This issue can be triggered via xfstests/generic/308. The reason is that the end_index is unsigned long with maximum value '2^32-1=4294967295' on 32-bit platform, and the given offset cause it wrapped to 0, so that the following codes will repeat again and again until the task schedule time out: end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Just skip the page if it is fully outside i_size, e.g. due * to a truncate operation that is in progress. */ if (page->index >= end_index + 1 || offset_into_page == 0) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlock_page(page); return 0; } In order to check if a page is fully outsids i_size or not, we can fix the code logic as below: if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) Secondly, there still has another similar issue when calculating the end offset for mapping the filesystem blocks to the file blocks for delalloc. With the same tests to above, run unmount(8) will cause kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: XFS_FORCED_SHUTDOWN(ip->i_mount) || \ ip->i_delayed_blks == 0, file: fs/xfs/xfs_super.c, line: 964 kernel BUG at fs/xfs/xfs_message.c:108! invalid opcode: 0000 [#1] SMP task: edddc100 ti: ec6ee000 task.ti: ec6ee000 EIP: 0060:[<f83d87cb>] EFLAGS: 00010296 CPU: 1 EIP is at assfail+0x2b/0x30 [xfs] .............. Call Trace: [<f83d9cd4>] xfs_fs_destroy_inode+0x74/0x120 [xfs] [<c115ddf1>] destroy_inode+0x31/0x50 [<c115deff>] evict+0xef/0x170 [<c115dfb2>] dispose_list+0x32/0x40 [<c115ea3a>] evict_inodes+0xca/0xe0 [<c1149706>] generic_shutdown_super+0x46/0xd0 [<c11497b9>] kill_block_super+0x29/0x70 [<c1149a14>] deactivate_locked_super+0x44/0x70 [<c114a427>] deactivate_super+0x47/0x60 [<c1161c3d>] mntput_no_expire+0xcd/0x120 [<c1162ae8>] SyS_umount+0xa8/0x370 [<c1162dce>] SyS_oldumount+0x1e/0x20 [<c15be18d>] sysenter_do_call+0x12/0x28 That because the end_offset is evaluated to 0 which is the same reason to above, hence the mapping and covertion for dealloc file blocks to file system blocks did not happened. This patch just fixed both issues. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-20 06:24:26 +08:00
/* Adjust the end_offset to the end of file */
end_offset = offset;
}
return xfs_writepage_map(wpc, wbc, inode, page, end_offset);
redirty:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
STATIC int
xfs_vm_writepage(
struct page *page,
struct writeback_control *wbc)
{
struct xfs_writepage_ctx wpc = {
.io_type = XFS_IO_INVALID,
};
int ret;
ret = xfs_do_writepage(page, wbc, &wpc);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
if (wpc.ioend)
ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
return ret;
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
}
STATIC int
xfs_vm_writepages(
struct address_space *mapping,
struct writeback_control *wbc)
{
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
struct xfs_writepage_ctx wpc = {
.io_type = XFS_IO_INVALID,
};
int ret;
xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
if (dax_mapping(mapping))
return dax_writeback_mapping_range(mapping,
xfs_find_bdev_for_inode(mapping->host), wbc);
xfs: Introduce writeback context for writepages xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:21:19 +08:00
ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);
xfs: don't chain ioends during writepage submission Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-15 14:23:12 +08:00
if (wpc.ioend)
ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
return ret;
}
/*
* Called to move a page into cleanable state - and from there
* to be released. The page should already be clean. We always
* have buffer heads in this call.
*
* Returns 1 if the page is ok to release, 0 otherwise.
*/
STATIC int
xfs_vm_releasepage(
struct page *page,
gfp_t gfp_mask)
{
int delalloc, unwritten;
trace_xfs_releasepage(page->mapping->host, page, 0, 0);
xfs: skip dirty pages in ->releasepage() XFS has had scattered reports of delalloc blocks present at ->releasepage() time. This results in a warning with a stack trace similar to the following: ... Call Trace: [<ffffffffa23c5b8f>] dump_stack+0x63/0x84 [<ffffffffa20837a7>] warn_slowpath_common+0x97/0xe0 [<ffffffffa208380a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa2326caf>] xfs_vm_releasepage+0x10f/0x140 [<ffffffffa218c680>] ? page_mkclean_one+0xd0/0xd0 [<ffffffffa218d3a0>] ? anon_vma_prepare+0x150/0x150 [<ffffffffa21521c2>] try_to_release_page+0x32/0x50 [<ffffffffa2166b2e>] shrink_active_list+0x3ce/0x3e0 [<ffffffffa21671c7>] shrink_lruvec+0x687/0x7d0 [<ffffffffa21673ec>] shrink_zone+0xdc/0x2c0 [<ffffffffa2168539>] kswapd+0x4f9/0x970 [<ffffffffa2168040>] ? mem_cgroup_shrink_node_zone+0x1a0/0x1a0 [<ffffffffa20a0d99>] kthread+0xc9/0xe0 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 [<ffffffffa26b404f>] ret_from_fork+0x3f/0x70 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 This occurs because it is possible for shrink_active_list() to send pages marked dirty to ->releasepage() when certain buffer_head threshold conditions are met. shrink_active_list() doesn't check the page dirty state apparently to handle an old ext3 corner case where in some cases clean pages would not have the dirty bit cleared, thus it is up to the filesystem to determine how to handle the page. XFS currently handles the delalloc case properly, but this behavior makes the warning spurious. Update the XFS ->releasepage() handler to explicitly skip dirty pages. Retain the existing delalloc/unwritten checks so we continue to warn if such buffers exist on clean pages when they shouldn't. Diagnosed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-22 07:50:38 +08:00
/*
* mm accommodates an old ext3 case where clean pages might not have had
* the dirty bit cleared. Thus, it can send actual dirty pages to
* ->releasepage() via shrink_active_list(). Conversely,
xfs: cancel dirty pages on invalidation Recently we've had warnings arise from the vm handing us pages without bufferheads attached to them. This should not ever occur in XFS, but we don't defend against it properly if it does. The only place where we remove bufferheads from a page is in xfs_vm_releasepage(), but we can't tell the difference here between "page is dirty so don't release" and "page is dirty but is being invalidated so release it". In some places that are invalidating pages ask for pages to be released and follow up afterward calling ->releasepage by checking whether the page was dirty and then aborting the invalidation. This is a possible vector for releasing buffers from a page but then leaving it in the mapping, so we really do need to avoid dirty pages in xfs_vm_releasepage(). To differentiate between invalidated pages and normal pages, we need to clear the page dirty flag when invalidating the pages. This can be done through xfs_vm_invalidatepage(), and will result xfs_vm_releasepage() seeing the page as clean which matches the bufferhead state on the page after calling block_invalidatepage(). Hence we can re-add the page dirty check in xfs_vm_releasepage to catch the case where we might be releasing a page that is actually dirty and so should not have the bufferheads on it removed. This will remove one possible vector of "dirty page with no bufferheads" and so help narrow down the search for the root cause of that problem. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:45 +08:00
* block_invalidatepage() can send pages that are still marked dirty but
* otherwise have invalidated buffers.
xfs: skip dirty pages in ->releasepage() XFS has had scattered reports of delalloc blocks present at ->releasepage() time. This results in a warning with a stack trace similar to the following: ... Call Trace: [<ffffffffa23c5b8f>] dump_stack+0x63/0x84 [<ffffffffa20837a7>] warn_slowpath_common+0x97/0xe0 [<ffffffffa208380a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa2326caf>] xfs_vm_releasepage+0x10f/0x140 [<ffffffffa218c680>] ? page_mkclean_one+0xd0/0xd0 [<ffffffffa218d3a0>] ? anon_vma_prepare+0x150/0x150 [<ffffffffa21521c2>] try_to_release_page+0x32/0x50 [<ffffffffa2166b2e>] shrink_active_list+0x3ce/0x3e0 [<ffffffffa21671c7>] shrink_lruvec+0x687/0x7d0 [<ffffffffa21673ec>] shrink_zone+0xdc/0x2c0 [<ffffffffa2168539>] kswapd+0x4f9/0x970 [<ffffffffa2168040>] ? mem_cgroup_shrink_node_zone+0x1a0/0x1a0 [<ffffffffa20a0d99>] kthread+0xc9/0xe0 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 [<ffffffffa26b404f>] ret_from_fork+0x3f/0x70 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 This occurs because it is possible for shrink_active_list() to send pages marked dirty to ->releasepage() when certain buffer_head threshold conditions are met. shrink_active_list() doesn't check the page dirty state apparently to handle an old ext3 corner case where in some cases clean pages would not have the dirty bit cleared, thus it is up to the filesystem to determine how to handle the page. XFS currently handles the delalloc case properly, but this behavior makes the warning spurious. Update the XFS ->releasepage() handler to explicitly skip dirty pages. Retain the existing delalloc/unwritten checks so we continue to warn if such buffers exist on clean pages when they shouldn't. Diagnosed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-22 07:50:38 +08:00
*
* We want to release the latter to avoid unnecessary buildup of the
xfs: cancel dirty pages on invalidation Recently we've had warnings arise from the vm handing us pages without bufferheads attached to them. This should not ever occur in XFS, but we don't defend against it properly if it does. The only place where we remove bufferheads from a page is in xfs_vm_releasepage(), but we can't tell the difference here between "page is dirty so don't release" and "page is dirty but is being invalidated so release it". In some places that are invalidating pages ask for pages to be released and follow up afterward calling ->releasepage by checking whether the page was dirty and then aborting the invalidation. This is a possible vector for releasing buffers from a page but then leaving it in the mapping, so we really do need to avoid dirty pages in xfs_vm_releasepage(). To differentiate between invalidated pages and normal pages, we need to clear the page dirty flag when invalidating the pages. This can be done through xfs_vm_invalidatepage(), and will result xfs_vm_releasepage() seeing the page as clean which matches the bufferhead state on the page after calling block_invalidatepage(). Hence we can re-add the page dirty check in xfs_vm_releasepage to catch the case where we might be releasing a page that is actually dirty and so should not have the bufferheads on it removed. This will remove one possible vector of "dirty page with no bufferheads" and so help narrow down the search for the root cause of that problem. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:45 +08:00
* LRU, so xfs_vm_invalidatepage() clears the page dirty flag on pages
* that are entirely invalidated and need to be released. Hence the
* only time we should get dirty pages here is through
* shrink_active_list() and so we can simply skip those now.
*
* warn if we've left any lingering delalloc/unwritten buffers on clean
* or invalidated pages we are about to release.
xfs: skip dirty pages in ->releasepage() XFS has had scattered reports of delalloc blocks present at ->releasepage() time. This results in a warning with a stack trace similar to the following: ... Call Trace: [<ffffffffa23c5b8f>] dump_stack+0x63/0x84 [<ffffffffa20837a7>] warn_slowpath_common+0x97/0xe0 [<ffffffffa208380a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa2326caf>] xfs_vm_releasepage+0x10f/0x140 [<ffffffffa218c680>] ? page_mkclean_one+0xd0/0xd0 [<ffffffffa218d3a0>] ? anon_vma_prepare+0x150/0x150 [<ffffffffa21521c2>] try_to_release_page+0x32/0x50 [<ffffffffa2166b2e>] shrink_active_list+0x3ce/0x3e0 [<ffffffffa21671c7>] shrink_lruvec+0x687/0x7d0 [<ffffffffa21673ec>] shrink_zone+0xdc/0x2c0 [<ffffffffa2168539>] kswapd+0x4f9/0x970 [<ffffffffa2168040>] ? mem_cgroup_shrink_node_zone+0x1a0/0x1a0 [<ffffffffa20a0d99>] kthread+0xc9/0xe0 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 [<ffffffffa26b404f>] ret_from_fork+0x3f/0x70 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 This occurs because it is possible for shrink_active_list() to send pages marked dirty to ->releasepage() when certain buffer_head threshold conditions are met. shrink_active_list() doesn't check the page dirty state apparently to handle an old ext3 corner case where in some cases clean pages would not have the dirty bit cleared, thus it is up to the filesystem to determine how to handle the page. XFS currently handles the delalloc case properly, but this behavior makes the warning spurious. Update the XFS ->releasepage() handler to explicitly skip dirty pages. Retain the existing delalloc/unwritten checks so we continue to warn if such buffers exist on clean pages when they shouldn't. Diagnosed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-22 07:50:38 +08:00
*/
xfs: cancel dirty pages on invalidation Recently we've had warnings arise from the vm handing us pages without bufferheads attached to them. This should not ever occur in XFS, but we don't defend against it properly if it does. The only place where we remove bufferheads from a page is in xfs_vm_releasepage(), but we can't tell the difference here between "page is dirty so don't release" and "page is dirty but is being invalidated so release it". In some places that are invalidating pages ask for pages to be released and follow up afterward calling ->releasepage by checking whether the page was dirty and then aborting the invalidation. This is a possible vector for releasing buffers from a page but then leaving it in the mapping, so we really do need to avoid dirty pages in xfs_vm_releasepage(). To differentiate between invalidated pages and normal pages, we need to clear the page dirty flag when invalidating the pages. This can be done through xfs_vm_invalidatepage(), and will result xfs_vm_releasepage() seeing the page as clean which matches the bufferhead state on the page after calling block_invalidatepage(). Hence we can re-add the page dirty check in xfs_vm_releasepage to catch the case where we might be releasing a page that is actually dirty and so should not have the bufferheads on it removed. This will remove one possible vector of "dirty page with no bufferheads" and so help narrow down the search for the root cause of that problem. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:45 +08:00
if (PageDirty(page))
return 0;
xfs_count_page_state(page, &delalloc, &unwritten);
xfs: cancel dirty pages on invalidation Recently we've had warnings arise from the vm handing us pages without bufferheads attached to them. This should not ever occur in XFS, but we don't defend against it properly if it does. The only place where we remove bufferheads from a page is in xfs_vm_releasepage(), but we can't tell the difference here between "page is dirty so don't release" and "page is dirty but is being invalidated so release it". In some places that are invalidating pages ask for pages to be released and follow up afterward calling ->releasepage by checking whether the page was dirty and then aborting the invalidation. This is a possible vector for releasing buffers from a page but then leaving it in the mapping, so we really do need to avoid dirty pages in xfs_vm_releasepage(). To differentiate between invalidated pages and normal pages, we need to clear the page dirty flag when invalidating the pages. This can be done through xfs_vm_invalidatepage(), and will result xfs_vm_releasepage() seeing the page as clean which matches the bufferhead state on the page after calling block_invalidatepage(). Hence we can re-add the page dirty check in xfs_vm_releasepage to catch the case where we might be releasing a page that is actually dirty and so should not have the bufferheads on it removed. This will remove one possible vector of "dirty page with no bufferheads" and so help narrow down the search for the root cause of that problem. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:45 +08:00
if (WARN_ON_ONCE(delalloc))
return 0;
xfs: cancel dirty pages on invalidation Recently we've had warnings arise from the vm handing us pages without bufferheads attached to them. This should not ever occur in XFS, but we don't defend against it properly if it does. The only place where we remove bufferheads from a page is in xfs_vm_releasepage(), but we can't tell the difference here between "page is dirty so don't release" and "page is dirty but is being invalidated so release it". In some places that are invalidating pages ask for pages to be released and follow up afterward calling ->releasepage by checking whether the page was dirty and then aborting the invalidation. This is a possible vector for releasing buffers from a page but then leaving it in the mapping, so we really do need to avoid dirty pages in xfs_vm_releasepage(). To differentiate between invalidated pages and normal pages, we need to clear the page dirty flag when invalidating the pages. This can be done through xfs_vm_invalidatepage(), and will result xfs_vm_releasepage() seeing the page as clean which matches the bufferhead state on the page after calling block_invalidatepage(). Hence we can re-add the page dirty check in xfs_vm_releasepage to catch the case where we might be releasing a page that is actually dirty and so should not have the bufferheads on it removed. This will remove one possible vector of "dirty page with no bufferheads" and so help narrow down the search for the root cause of that problem. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-14 00:47:45 +08:00
if (WARN_ON_ONCE(unwritten))
return 0;
return try_to_free_buffers(page);
}
/*
* If this is O_DIRECT or the mpage code calling tell them how large the mapping
* is, so that we can avoid repeated get_blocks calls.
*
* If the mapping spans EOF, then we have to break the mapping up as the mapping
* for blocks beyond EOF must be marked new so that sub block regions can be
* correctly zeroed. We can't do this for mappings within EOF unless the mapping
* was just allocated or is unwritten, otherwise the callers would overwrite
* existing data with zeros. Hence we have to split the mapping into a range up
* to and including EOF, and a second mapping for beyond EOF.
*/
static void
xfs_map_trim_size(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
struct xfs_bmbt_irec *imap,
xfs_off_t offset,
ssize_t size)
{
xfs_off_t mapping_size;
mapping_size = imap->br_startoff + imap->br_blockcount - iblock;
mapping_size <<= inode->i_blkbits;
ASSERT(mapping_size > 0);
if (mapping_size > size)
mapping_size = size;
if (offset < i_size_read(inode) &&
(xfs_ufsize_t)offset + mapping_size >= i_size_read(inode)) {
/* limit mapping to block that spans EOF */
mapping_size = roundup_64(i_size_read(inode) - offset,
i_blocksize(inode));
}
if (mapping_size > LONG_MAX)
mapping_size = LONG_MAX;
bh_result->b_size = mapping_size;
}
static int
xfs_get_blocks(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb, end_fsb;
int error = 0;
int lockmode = 0;
struct xfs_bmbt_irec imap;
int nimaps = 1;
xfs_off_t offset;
ssize_t size;
BUG_ON(create);
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
offset = (xfs_off_t)iblock << inode->i_blkbits;
ASSERT(bh_result->b_size >= i_blocksize(inode));
size = bh_result->b_size;
if (offset >= i_size_read(inode))
return 0;
/*
* Direct I/O is usually done on preallocated files, so try getting
* a block mapping without an exclusive lock first.
*/
lockmode = xfs_ilock_data_map_shared(ip);
ASSERT(offset <= mp->m_super->s_maxbytes);
if ((xfs_ufsize_t)offset + size > mp->m_super->s_maxbytes)
size = mp->m_super->s_maxbytes - offset;
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
&imap, &nimaps, XFS_BMAPI_ENTIRE);
if (error)
goto out_unlock;
if (nimaps) {
trace_xfs_get_blocks_found(ip, offset, size,
imap.br_state == XFS_EXT_UNWRITTEN ?
XFS_IO_UNWRITTEN : XFS_IO_OVERWRITE, &imap);
xfs_iunlock(ip, lockmode);
} else {
trace_xfs_get_blocks_notfound(ip, offset, size);
goto out_unlock;
}
/* trim mapping down to size requested */
xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size);
/*
* For unwritten extents do not report a disk address in the buffered
* read case (treat as if we're reading into a hole).
*/
if (xfs_bmap_is_real_extent(&imap))
xfs_map_buffer(inode, bh_result, &imap, offset);
/*
* If this is a realtime file, data may be on a different device.
* to that pointed to from the buffer_head b_bdev currently.
*/
bh_result->b_bdev = xfs_find_bdev_for_inode(inode);
return 0;
out_unlock:
xfs_iunlock(ip, lockmode);
return error;
}
STATIC ssize_t
xfs_vm_direct_IO(
struct kiocb *iocb,
struct iov_iter *iter)
{
xfs: fix assertion failure in xfs_vm_write_failed() In xfs_vm_write_failed(), we evaluate the block_offset of pos with PAGE_MASK which is an unsigned long. That is fine on 64-bit platforms regardless of whether the request pos is 32-bit or 64-bit. However, on 32-bit platforms the value is 0xfffff000 and so the high 32 bits in it will be masked off with (pos & PAGE_MASK) for a 64-bit pos. As a result, the evaluated block_offset is incorrect which will cause this failure ASSERT(block_offset + from == pos); and potentially pass the wrong block to xfs_vm_kill_delalloc_range(). In this case, we can get a kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: block_offset + from == pos, file: fs/xfs/xfs_aops.c, line: 1504 ------------[ cut here ]------------ kernel BUG at fs/xfs/xfs_message.c:100! invalid opcode: 0000 [#1] SMP ........ Pid: 4057, comm: mkfs.xfs Tainted: G O 3.9.0-rc2 #1 EIP: 0060:[<f94a7e8b>] EFLAGS: 00010282 CPU: 0 EIP is at assfail+0x2b/0x30 [xfs] EAX: 00000056 EBX: f6ef28a0 ECX: 00000007 EDX: f57d22a4 ESI: 1c2fb000 EDI: 00000000 EBP: ea6b5d30 ESP: ea6b5d1c DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 094f3ff4 CR3: 2bcb4000 CR4: 000006f0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process mkfs.xfs (pid: 4057, ti=ea6b4000 task=ea5799e0 task.ti=ea6b4000) Stack: 00000000 f9525c48 f951fa80 f951f96b 000005e4 ea6b5d7c f9494b34 c19b0ea2 00000066 f3d6c620 c19b0ea2 00000000 e9a91458 00001000 00000000 00000000 00000000 c15c7e89 00000000 1c2fb000 00000000 00000000 1c2fb000 00000080 Call Trace: [<f9494b34>] xfs_vm_write_failed+0x74/0x1b0 [xfs] [<c15c7e89>] ? printk+0x4d/0x4f [<f9494d7d>] xfs_vm_write_begin+0x10d/0x170 [xfs] [<c110a34c>] generic_file_buffered_write+0xdc/0x210 [<f949b669>] xfs_file_buffered_aio_write+0xf9/0x190 [xfs] [<f949b7f3>] xfs_file_aio_write+0xf3/0x160 [xfs] [<c115e504>] do_sync_write+0x94/0xd0 [<c115ed1f>] vfs_write+0x8f/0x160 [<c115e470>] ? wait_on_retry_sync_kiocb+0x50/0x50 [<c115f017>] sys_write+0x47/0x80 [<c15d860d>] sysenter_do_call+0x12/0x28 ............. EIP: [<f94a7e8b>] assfail+0x2b/0x30 [xfs] SS:ESP 0068:ea6b5d1c ---[ end trace cdd9af4f4ecab42f ]--- Kernel panic - not syncing: Fatal exception In order to avoid this, we can evaluate the block_offset of the start of the page by using shifts rather than masks the mismatch problem. Thanks Dave Chinner for help finding and fixing this bug. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Reviewed-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-07-16 13:11:16 +08:00
/*
* We just need the method present so that open/fcntl allow direct I/O.
xfs: fix assertion failure in xfs_vm_write_failed() In xfs_vm_write_failed(), we evaluate the block_offset of pos with PAGE_MASK which is an unsigned long. That is fine on 64-bit platforms regardless of whether the request pos is 32-bit or 64-bit. However, on 32-bit platforms the value is 0xfffff000 and so the high 32 bits in it will be masked off with (pos & PAGE_MASK) for a 64-bit pos. As a result, the evaluated block_offset is incorrect which will cause this failure ASSERT(block_offset + from == pos); and potentially pass the wrong block to xfs_vm_kill_delalloc_range(). In this case, we can get a kernel panic if CONFIG_XFS_DEBUG is enabled: XFS: Assertion failed: block_offset + from == pos, file: fs/xfs/xfs_aops.c, line: 1504 ------------[ cut here ]------------ kernel BUG at fs/xfs/xfs_message.c:100! invalid opcode: 0000 [#1] SMP ........ Pid: 4057, comm: mkfs.xfs Tainted: G O 3.9.0-rc2 #1 EIP: 0060:[<f94a7e8b>] EFLAGS: 00010282 CPU: 0 EIP is at assfail+0x2b/0x30 [xfs] EAX: 00000056 EBX: f6ef28a0 ECX: 00000007 EDX: f57d22a4 ESI: 1c2fb000 EDI: 00000000 EBP: ea6b5d30 ESP: ea6b5d1c DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 094f3ff4 CR3: 2bcb4000 CR4: 000006f0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process mkfs.xfs (pid: 4057, ti=ea6b4000 task=ea5799e0 task.ti=ea6b4000) Stack: 00000000 f9525c48 f951fa80 f951f96b 000005e4 ea6b5d7c f9494b34 c19b0ea2 00000066 f3d6c620 c19b0ea2 00000000 e9a91458 00001000 00000000 00000000 00000000 c15c7e89 00000000 1c2fb000 00000000 00000000 1c2fb000 00000080 Call Trace: [<f9494b34>] xfs_vm_write_failed+0x74/0x1b0 [xfs] [<c15c7e89>] ? printk+0x4d/0x4f [<f9494d7d>] xfs_vm_write_begin+0x10d/0x170 [xfs] [<c110a34c>] generic_file_buffered_write+0xdc/0x210 [<f949b669>] xfs_file_buffered_aio_write+0xf9/0x190 [xfs] [<f949b7f3>] xfs_file_aio_write+0xf3/0x160 [xfs] [<c115e504>] do_sync_write+0x94/0xd0 [<c115ed1f>] vfs_write+0x8f/0x160 [<c115e470>] ? wait_on_retry_sync_kiocb+0x50/0x50 [<c115f017>] sys_write+0x47/0x80 [<c15d860d>] sysenter_do_call+0x12/0x28 ............. EIP: [<f94a7e8b>] assfail+0x2b/0x30 [xfs] SS:ESP 0068:ea6b5d1c ---[ end trace cdd9af4f4ecab42f ]--- Kernel panic - not syncing: Fatal exception In order to avoid this, we can evaluate the block_offset of the start of the page by using shifts rather than masks the mismatch problem. Thanks Dave Chinner for help finding and fixing this bug. Reported-by: Michael L. Semon <mlsemon35@gmail.com> Reviewed-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-07-16 13:11:16 +08:00
*/
return -EINVAL;
}
STATIC sector_t
xfs_vm_bmap(
struct address_space *mapping,
sector_t block)
{
struct inode *inode = (struct inode *)mapping->host;
struct xfs_inode *ip = XFS_I(inode);
trace_xfs_vm_bmap(XFS_I(inode));
/*
* The swap code (ab-)uses ->bmap to get a block mapping and then
* bypasseѕ the file system for actual I/O. We really can't allow
* that on reflinks inodes, so we have to skip out here. And yes,
* 0 is the magic code for a bmap error.
*
* Since we don't pass back blockdev info, we can't return bmap
* information for rt files either.
*/
if (xfs_is_reflink_inode(ip) || XFS_IS_REALTIME_INODE(ip))
return 0;
filemap_write_and_wait(mapping);
return generic_block_bmap(mapping, block, xfs_get_blocks);
}
STATIC int
xfs_vm_readpage(
struct file *unused,
struct page *page)
{
trace_xfs_vm_readpage(page->mapping->host, 1);
return mpage_readpage(page, xfs_get_blocks);
}
STATIC int
xfs_vm_readpages(
struct file *unused,
struct address_space *mapping,
struct list_head *pages,
unsigned nr_pages)
{
trace_xfs_vm_readpages(mapping->host, nr_pages);
return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
}
xfs: don't dirty buffers beyond EOF generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. cc: <stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-02 10:12:51 +08:00
/*
* This is basically a copy of __set_page_dirty_buffers() with one
* small tweak: buffers beyond EOF do not get marked dirty. If we mark them
* dirty, we'll never be able to clean them because we don't write buffers
* beyond EOF, and that means we can't invalidate pages that span EOF
* that have been marked dirty. Further, the dirty state can leak into
* the file interior if the file is extended, resulting in all sorts of
* bad things happening as the state does not match the underlying data.
*
* XXX: this really indicates that bufferheads in XFS need to die. Warts like
* this only exist because of bufferheads and how the generic code manages them.
*/
STATIC int
xfs_vm_set_page_dirty(
struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
loff_t end_offset;
loff_t offset;
int newly_dirty;
if (unlikely(!mapping))
return !TestSetPageDirty(page);
end_offset = i_size_read(inode);
offset = page_offset(page);
spin_lock(&mapping->private_lock);
if (page_has_buffers(page)) {
struct buffer_head *head = page_buffers(page);
struct buffer_head *bh = head;
do {
if (offset < end_offset)
set_buffer_dirty(bh);
bh = bh->b_this_page;
offset += i_blocksize(inode);
xfs: don't dirty buffers beyond EOF generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. cc: <stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-02 10:12:51 +08:00
} while (bh != head);
}
memcg: add per cgroup dirty page accounting When modifying PG_Dirty on cached file pages, update the new MEM_CGROUP_STAT_DIRTY counter. This is done in the same places where global NR_FILE_DIRTY is managed. The new memcg stat is visible in the per memcg memory.stat cgroupfs file. The most recent past attempt at this was http://thread.gmane.org/gmane.linux.kernel.cgroups/8632 The new accounting supports future efforts to add per cgroup dirty page throttling and writeback. It also helps an administrator break down a container's memory usage and provides evidence to understand memcg oom kills (the new dirty count is included in memcg oom kill messages). The ability to move page accounting between memcg (memory.move_charge_at_immigrate) makes this accounting more complicated than the global counter. The existing mem_cgroup_{begin,end}_page_stat() lock is used to serialize move accounting with stat updates. Typical update operation: memcg = mem_cgroup_begin_page_stat(page) if (TestSetPageDirty()) { [...] mem_cgroup_update_page_stat(memcg) } mem_cgroup_end_page_stat(memcg) Summary of mem_cgroup_end_page_stat() overhead: - Without CONFIG_MEMCG it's a no-op - With CONFIG_MEMCG and no inter memcg task movement, it's just rcu_read_lock() - With CONFIG_MEMCG and inter memcg task movement, it's rcu_read_lock() + spin_lock_irqsave() A memcg parameter is added to several routines because their callers now grab mem_cgroup_begin_page_stat() which returns the memcg later needed by for mem_cgroup_update_page_stat(). Because mem_cgroup_begin_page_stat() may disable interrupts, some adjustments are needed: - move __mark_inode_dirty() from __set_page_dirty() to its caller. __mark_inode_dirty() locking does not want interrupts disabled. - use spin_lock_irqsave(tree_lock) rather than spin_lock_irq() in __delete_from_page_cache(), replace_page_cache_page(), invalidate_complete_page2(), and __remove_mapping(). text data bss dec hex filename 8925147 1774832 1785856 12485835 be84cb vmlinux-!CONFIG_MEMCG-before 8925339 1774832 1785856 12486027 be858b vmlinux-!CONFIG_MEMCG-after +192 text bytes 8965977 1784992 1785856 12536825 bf4bf9 vmlinux-CONFIG_MEMCG-before 8966750 1784992 1785856 12537598 bf4efe vmlinux-CONFIG_MEMCG-after +773 text bytes Performance tests run on v4.0-rc1-36-g4f671fe2f952. Lower is better for all metrics, they're all wall clock or cycle counts. The read and write fault benchmarks just measure fault time, they do not include I/O time. * CONFIG_MEMCG not set: baseline patched kbuild 1m25.030000(+-0.088% 3 samples) 1m25.426667(+-0.120% 3 samples) dd write 100 MiB 0.859211561 +-15.10% 0.874162885 +-15.03% dd write 200 MiB 1.670653105 +-17.87% 1.669384764 +-11.99% dd write 1000 MiB 8.434691190 +-14.15% 8.474733215 +-14.77% read fault cycles 254.0(+-0.000% 10 samples) 253.0(+-0.000% 10 samples) write fault cycles 2021.2(+-3.070% 10 samples) 1984.5(+-1.036% 10 samples) * CONFIG_MEMCG=y root_memcg: baseline patched kbuild 1m25.716667(+-0.105% 3 samples) 1m25.686667(+-0.153% 3 samples) dd write 100 MiB 0.855650830 +-14.90% 0.887557919 +-14.90% dd write 200 MiB 1.688322953 +-12.72% 1.667682724 +-13.33% dd write 1000 MiB 8.418601605 +-14.30% 8.673532299 +-15.00% read fault cycles 266.0(+-0.000% 10 samples) 266.0(+-0.000% 10 samples) write fault cycles 2051.7(+-1.349% 10 samples) 2049.6(+-1.686% 10 samples) * CONFIG_MEMCG=y non-root_memcg: baseline patched kbuild 1m26.120000(+-0.273% 3 samples) 1m25.763333(+-0.127% 3 samples) dd write 100 MiB 0.861723964 +-15.25% 0.818129350 +-14.82% dd write 200 MiB 1.669887569 +-13.30% 1.698645885 +-13.27% dd write 1000 MiB 8.383191730 +-14.65% 8.351742280 +-14.52% read fault cycles 265.7(+-0.172% 10 samples) 267.0(+-0.000% 10 samples) write fault cycles 2070.6(+-1.512% 10 samples) 2084.4(+-2.148% 10 samples) As expected anon page faults are not affected by this patch. tj: Updated to apply on top of the recent cancel_dirty_page() changes. Signed-off-by: Sha Zhengju <handai.szj@gmail.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-23 05:13:16 +08:00
/*
* Lock out page->mem_cgroup migration to keep PageDirty
* synchronized with per-memcg dirty page counters.
memcg: add per cgroup dirty page accounting When modifying PG_Dirty on cached file pages, update the new MEM_CGROUP_STAT_DIRTY counter. This is done in the same places where global NR_FILE_DIRTY is managed. The new memcg stat is visible in the per memcg memory.stat cgroupfs file. The most recent past attempt at this was http://thread.gmane.org/gmane.linux.kernel.cgroups/8632 The new accounting supports future efforts to add per cgroup dirty page throttling and writeback. It also helps an administrator break down a container's memory usage and provides evidence to understand memcg oom kills (the new dirty count is included in memcg oom kill messages). The ability to move page accounting between memcg (memory.move_charge_at_immigrate) makes this accounting more complicated than the global counter. The existing mem_cgroup_{begin,end}_page_stat() lock is used to serialize move accounting with stat updates. Typical update operation: memcg = mem_cgroup_begin_page_stat(page) if (TestSetPageDirty()) { [...] mem_cgroup_update_page_stat(memcg) } mem_cgroup_end_page_stat(memcg) Summary of mem_cgroup_end_page_stat() overhead: - Without CONFIG_MEMCG it's a no-op - With CONFIG_MEMCG and no inter memcg task movement, it's just rcu_read_lock() - With CONFIG_MEMCG and inter memcg task movement, it's rcu_read_lock() + spin_lock_irqsave() A memcg parameter is added to several routines because their callers now grab mem_cgroup_begin_page_stat() which returns the memcg later needed by for mem_cgroup_update_page_stat(). Because mem_cgroup_begin_page_stat() may disable interrupts, some adjustments are needed: - move __mark_inode_dirty() from __set_page_dirty() to its caller. __mark_inode_dirty() locking does not want interrupts disabled. - use spin_lock_irqsave(tree_lock) rather than spin_lock_irq() in __delete_from_page_cache(), replace_page_cache_page(), invalidate_complete_page2(), and __remove_mapping(). text data bss dec hex filename 8925147 1774832 1785856 12485835 be84cb vmlinux-!CONFIG_MEMCG-before 8925339 1774832 1785856 12486027 be858b vmlinux-!CONFIG_MEMCG-after +192 text bytes 8965977 1784992 1785856 12536825 bf4bf9 vmlinux-CONFIG_MEMCG-before 8966750 1784992 1785856 12537598 bf4efe vmlinux-CONFIG_MEMCG-after +773 text bytes Performance tests run on v4.0-rc1-36-g4f671fe2f952. Lower is better for all metrics, they're all wall clock or cycle counts. The read and write fault benchmarks just measure fault time, they do not include I/O time. * CONFIG_MEMCG not set: baseline patched kbuild 1m25.030000(+-0.088% 3 samples) 1m25.426667(+-0.120% 3 samples) dd write 100 MiB 0.859211561 +-15.10% 0.874162885 +-15.03% dd write 200 MiB 1.670653105 +-17.87% 1.669384764 +-11.99% dd write 1000 MiB 8.434691190 +-14.15% 8.474733215 +-14.77% read fault cycles 254.0(+-0.000% 10 samples) 253.0(+-0.000% 10 samples) write fault cycles 2021.2(+-3.070% 10 samples) 1984.5(+-1.036% 10 samples) * CONFIG_MEMCG=y root_memcg: baseline patched kbuild 1m25.716667(+-0.105% 3 samples) 1m25.686667(+-0.153% 3 samples) dd write 100 MiB 0.855650830 +-14.90% 0.887557919 +-14.90% dd write 200 MiB 1.688322953 +-12.72% 1.667682724 +-13.33% dd write 1000 MiB 8.418601605 +-14.30% 8.673532299 +-15.00% read fault cycles 266.0(+-0.000% 10 samples) 266.0(+-0.000% 10 samples) write fault cycles 2051.7(+-1.349% 10 samples) 2049.6(+-1.686% 10 samples) * CONFIG_MEMCG=y non-root_memcg: baseline patched kbuild 1m26.120000(+-0.273% 3 samples) 1m25.763333(+-0.127% 3 samples) dd write 100 MiB 0.861723964 +-15.25% 0.818129350 +-14.82% dd write 200 MiB 1.669887569 +-13.30% 1.698645885 +-13.27% dd write 1000 MiB 8.383191730 +-14.65% 8.351742280 +-14.52% read fault cycles 265.7(+-0.172% 10 samples) 267.0(+-0.000% 10 samples) write fault cycles 2070.6(+-1.512% 10 samples) 2084.4(+-2.148% 10 samples) As expected anon page faults are not affected by this patch. tj: Updated to apply on top of the recent cancel_dirty_page() changes. Signed-off-by: Sha Zhengju <handai.szj@gmail.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-23 05:13:16 +08:00
*/
lock_page_memcg(page);
xfs: don't dirty buffers beyond EOF generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. cc: <stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-02 10:12:51 +08:00
newly_dirty = !TestSetPageDirty(page);
spin_unlock(&mapping->private_lock);
if (newly_dirty) {
/* sigh - __set_page_dirty() is static, so copy it here, too */
unsigned long flags;
spin_lock_irqsave(&mapping->tree_lock, flags);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(!PageUptodate(page));
account_page_dirtied(page, mapping);
xfs: don't dirty buffers beyond EOF generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. cc: <stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-02 10:12:51 +08:00
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
spin_unlock_irqrestore(&mapping->tree_lock, flags);
}
unlock_page_memcg(page);
memcg: add per cgroup dirty page accounting When modifying PG_Dirty on cached file pages, update the new MEM_CGROUP_STAT_DIRTY counter. This is done in the same places where global NR_FILE_DIRTY is managed. The new memcg stat is visible in the per memcg memory.stat cgroupfs file. The most recent past attempt at this was http://thread.gmane.org/gmane.linux.kernel.cgroups/8632 The new accounting supports future efforts to add per cgroup dirty page throttling and writeback. It also helps an administrator break down a container's memory usage and provides evidence to understand memcg oom kills (the new dirty count is included in memcg oom kill messages). The ability to move page accounting between memcg (memory.move_charge_at_immigrate) makes this accounting more complicated than the global counter. The existing mem_cgroup_{begin,end}_page_stat() lock is used to serialize move accounting with stat updates. Typical update operation: memcg = mem_cgroup_begin_page_stat(page) if (TestSetPageDirty()) { [...] mem_cgroup_update_page_stat(memcg) } mem_cgroup_end_page_stat(memcg) Summary of mem_cgroup_end_page_stat() overhead: - Without CONFIG_MEMCG it's a no-op - With CONFIG_MEMCG and no inter memcg task movement, it's just rcu_read_lock() - With CONFIG_MEMCG and inter memcg task movement, it's rcu_read_lock() + spin_lock_irqsave() A memcg parameter is added to several routines because their callers now grab mem_cgroup_begin_page_stat() which returns the memcg later needed by for mem_cgroup_update_page_stat(). Because mem_cgroup_begin_page_stat() may disable interrupts, some adjustments are needed: - move __mark_inode_dirty() from __set_page_dirty() to its caller. __mark_inode_dirty() locking does not want interrupts disabled. - use spin_lock_irqsave(tree_lock) rather than spin_lock_irq() in __delete_from_page_cache(), replace_page_cache_page(), invalidate_complete_page2(), and __remove_mapping(). text data bss dec hex filename 8925147 1774832 1785856 12485835 be84cb vmlinux-!CONFIG_MEMCG-before 8925339 1774832 1785856 12486027 be858b vmlinux-!CONFIG_MEMCG-after +192 text bytes 8965977 1784992 1785856 12536825 bf4bf9 vmlinux-CONFIG_MEMCG-before 8966750 1784992 1785856 12537598 bf4efe vmlinux-CONFIG_MEMCG-after +773 text bytes Performance tests run on v4.0-rc1-36-g4f671fe2f952. Lower is better for all metrics, they're all wall clock or cycle counts. The read and write fault benchmarks just measure fault time, they do not include I/O time. * CONFIG_MEMCG not set: baseline patched kbuild 1m25.030000(+-0.088% 3 samples) 1m25.426667(+-0.120% 3 samples) dd write 100 MiB 0.859211561 +-15.10% 0.874162885 +-15.03% dd write 200 MiB 1.670653105 +-17.87% 1.669384764 +-11.99% dd write 1000 MiB 8.434691190 +-14.15% 8.474733215 +-14.77% read fault cycles 254.0(+-0.000% 10 samples) 253.0(+-0.000% 10 samples) write fault cycles 2021.2(+-3.070% 10 samples) 1984.5(+-1.036% 10 samples) * CONFIG_MEMCG=y root_memcg: baseline patched kbuild 1m25.716667(+-0.105% 3 samples) 1m25.686667(+-0.153% 3 samples) dd write 100 MiB 0.855650830 +-14.90% 0.887557919 +-14.90% dd write 200 MiB 1.688322953 +-12.72% 1.667682724 +-13.33% dd write 1000 MiB 8.418601605 +-14.30% 8.673532299 +-15.00% read fault cycles 266.0(+-0.000% 10 samples) 266.0(+-0.000% 10 samples) write fault cycles 2051.7(+-1.349% 10 samples) 2049.6(+-1.686% 10 samples) * CONFIG_MEMCG=y non-root_memcg: baseline patched kbuild 1m26.120000(+-0.273% 3 samples) 1m25.763333(+-0.127% 3 samples) dd write 100 MiB 0.861723964 +-15.25% 0.818129350 +-14.82% dd write 200 MiB 1.669887569 +-13.30% 1.698645885 +-13.27% dd write 1000 MiB 8.383191730 +-14.65% 8.351742280 +-14.52% read fault cycles 265.7(+-0.172% 10 samples) 267.0(+-0.000% 10 samples) write fault cycles 2070.6(+-1.512% 10 samples) 2084.4(+-2.148% 10 samples) As expected anon page faults are not affected by this patch. tj: Updated to apply on top of the recent cancel_dirty_page() changes. Signed-off-by: Sha Zhengju <handai.szj@gmail.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-23 05:13:16 +08:00
if (newly_dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
xfs: don't dirty buffers beyond EOF generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. cc: <stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-02 10:12:51 +08:00
return newly_dirty;
}
const struct address_space_operations xfs_address_space_operations = {
.readpage = xfs_vm_readpage,
.readpages = xfs_vm_readpages,
.writepage = xfs_vm_writepage,
.writepages = xfs_vm_writepages,
xfs: don't dirty buffers beyond EOF generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. cc: <stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-02 10:12:51 +08:00
.set_page_dirty = xfs_vm_set_page_dirty,
.releasepage = xfs_vm_releasepage,
.invalidatepage = xfs_vm_invalidatepage,
.bmap = xfs_vm_bmap,
.direct_IO = xfs_vm_direct_IO,
.migratepage = buffer_migrate_page,
xfs: pagecache usage optimization Hi. I introduced "is_partially_uptodate" aops for XFS. A page can have multiple buffers and even if a page is not uptodate, some buffers can be uptodate on pagesize != blocksize environment. This aops checks that all buffers which correspond to a part of a file that we want to read are uptodate. If so, we do not have to issue actual read IO to HDD even if a page is not uptodate because the portion we want to read are uptodate. "block_is_partially_uptodate" function is already used by ext2/3/4. With the following patch random read/write mixed workloads or random read after random write workloads can be optimized and we can get performance improvement. I did a performance test using the sysbench. #sysbench --num-threads=4 --max-requests=100000 --test=fileio --file-num=1 \ --file-block-size=8K --file-total-size=1G --file-test-mode=rndrw \ --file-fsync-freq=0 --file-rw-ratio=0.5 run -2.6.29-rc6 Test execution summary: total time: 123.8645s total number of events: 100000 total time taken by event execution: 442.4994 per-request statistics: min: 0.0000s avg: 0.0044s max: 0.3387s approx. 95 percentile: 0.0118s -2.6.29-rc6-patched Test execution summary: total time: 108.0757s total number of events: 100000 total time taken by event execution: 417.7505 per-request statistics: min: 0.0000s avg: 0.0042s max: 0.3217s approx. 95 percentile: 0.0118s arch: ia64 pagesize: 16k blocksize: 4k Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Felix Blyakher <felixb@sgi.com>
2009-03-29 15:53:38 +08:00
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};