linux/fs/xfs
Dave Chinner dbd0f52993 xfs: check buffer pin state after locking in delwri_submit
AIL flushing can get stuck here:

[316649.005769] INFO: task xfsaild/pmem1:324525 blocked for more than 123 seconds.
[316649.007807]       Not tainted 5.17.0-rc6-dgc+ #975
[316649.009186] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[316649.011720] task:xfsaild/pmem1   state:D stack:14544 pid:324525 ppid:     2 flags:0x00004000
[316649.014112] Call Trace:
[316649.014841]  <TASK>
[316649.015492]  __schedule+0x30d/0x9e0
[316649.017745]  schedule+0x55/0xd0
[316649.018681]  io_schedule+0x4b/0x80
[316649.019683]  xfs_buf_wait_unpin+0x9e/0xf0
[316649.021850]  __xfs_buf_submit+0x14a/0x230
[316649.023033]  xfs_buf_delwri_submit_buffers+0x107/0x280
[316649.024511]  xfs_buf_delwri_submit_nowait+0x10/0x20
[316649.025931]  xfsaild+0x27e/0x9d0
[316649.028283]  kthread+0xf6/0x120
[316649.030602]  ret_from_fork+0x1f/0x30

in the situation where flushing gets preempted between the unpin
check and the buffer trylock under nowait conditions:

	blk_start_plug(&plug);
	list_for_each_entry_safe(bp, n, buffer_list, b_list) {
		if (!wait_list) {
			if (xfs_buf_ispinned(bp)) {
				pinned++;
				continue;
			}
Here >>>>>>
			if (!xfs_buf_trylock(bp))
				continue;

This means submission is stuck until something else triggers a log
force to unpin the buffer.

To get onto the delwri list to begin with, the buffer pin state has
already been checked, and hence it's relatively rare we get a race
between flushing and encountering a pinned buffer in delwri
submission to begin with. Further, to increase the pin count the
buffer has to be locked, so the only way we can hit this race
without failing the trylock is to be preempted between the pincount
check seeing zero and the trylock being run.

Hence to avoid this problem, just invert the order of trylock vs
pin check. We shouldn't hit that many pinned buffers here, so
optimising away the trylock for pinned buffers should not matter for
performance at all.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-03-20 08:59:49 -07:00
..
libxfs xfs: constify xfs_name_dotdot 2022-03-14 10:23:17 -07:00
scrub xfs: fix online fsck handling of v5 feature bits on secondary supers 2022-01-12 09:45:21 -08:00
Kconfig xfs: fix Kconfig asking about XFS_SUPPORT_V4 when XFS_FS=n 2020-10-16 15:34:28 -07:00
kmem.c mm: introduce memalloc_retry_wait() 2022-01-15 16:30:29 +02:00
kmem.h xfs: remove kmem_zone typedef 2021-10-22 16:00:31 -07:00
Makefile
mrlock.h
xfs_acl.c overlayfs update for 5.15 2021-09-02 09:21:27 -07:00
xfs_acl.h vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
xfs_aops.c xfs, iomap: limit individual ioend chain lengths in writeback 2022-01-26 09:19:20 -08:00
xfs_aops.h
xfs_attr_inactive.c xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_attr_list.c xfs: replace XFS_FORCED_SHUTDOWN with xfs_is_shutdown 2021-08-19 10:07:13 -07:00
xfs_bio_io.c xfs: async blkdev cache flush 2021-06-21 10:05:51 -07:00
xfs_bmap_item.c xfs: create slab caches for frequently-used deferred items 2021-10-22 16:04:36 -07:00
xfs_bmap_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_bmap_util.c xfs: set prealloc flag in xfs_alloc_file_space() 2022-02-01 14:14:48 -08:00
xfs_bmap_util.h xfs: kill the XFS_IOC_{ALLOC,FREE}SP* ioctls 2022-01-17 09:16:41 -08:00
xfs_buf_item_recover.c xfs: check sb_meta_uuid for dabuf buffer recovery 2021-12-21 09:49:41 -08:00
xfs_buf_item.c xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_buf_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_buf.c xfs: check buffer pin state after locking in delwri_submit 2022-03-20 08:59:49 -07:00
xfs_buf.h dax: return the partition offset from fs_dax_get_by_bdev 2021-12-04 08:58:54 -08:00
xfs_dir2_readdir.c xfs: take the ILOCK when readdir inspects directory mapping data 2022-01-11 15:11:04 -08:00
xfs_discard.c xfs: convert mount flags to features 2021-08-19 10:07:12 -07:00
xfs_discard.h
xfs_dquot_item_recover.c xfs: replace xfs_sb_version checks with feature flag checks 2021-08-19 10:07:12 -07:00
xfs_dquot_item.c xfs: remove support for disabling quota accounting on a mounted file system 2021-08-06 11:05:36 -07:00
xfs_dquot_item.h xfs: remove support for disabling quota accounting on a mounted file system 2021-08-06 11:05:36 -07:00
xfs_dquot.c xfs: hold quota inode ILOCK_EXCL until the end of dqalloc 2022-01-06 10:43:30 -08:00
xfs_dquot.h xfs: queue inactivation immediately when quota is nearing enforcement 2021-08-09 10:52:18 -07:00
xfs_error.c xfs: sysfs: use default_groups in kobj_type 2022-01-06 10:43:30 -08:00
xfs_error.h xfs: add trace point for fs shutdown 2021-08-18 18:46:00 -07:00
xfs_export.c xfs: convert remaining mount flags to state flags 2021-08-19 10:07:13 -07:00
xfs_export.h
xfs_extent_busy.c xfs: pass perags through to the busy extent code 2021-06-02 10:48:24 +10:00
xfs_extent_busy.h xfs: pass perags through to the busy extent code 2021-06-02 10:48:24 +10:00
xfs_extfree_item.c xfs: reduce the size of struct xfs_extent_free_item 2021-10-22 16:04:36 -07:00
xfs_extfree_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_file.c xfs: ensure log flush at the end of a synchronous fallocate call 2022-02-01 14:14:48 -08:00
xfs_filestream.c xfs: convert remaining mount flags to state flags 2021-08-19 10:07:13 -07:00
xfs_filestream.h xfs: convert mount flags to features 2021-08-19 10:07:12 -07:00
xfs_fsmap.c xfs: don't generate selinux audit messages for capability testing 2022-03-09 10:32:06 -08:00
xfs_fsmap.h xfs: fix deadlock and streamline xfs_getfsmap performance 2020-10-07 08:40:29 -07:00
xfs_fsops.c xfs: convert remaining mount flags to state flags 2021-08-19 10:07:13 -07:00
xfs_fsops.h xfs: get rid of xfs_growfs_{data,log}_t 2021-02-03 09:18:50 -08:00
xfs_globals.c xfs: consolidate the eofblocks and cowblocks workers 2021-02-03 09:18:49 -08:00
xfs_health.c xfs: replace XFS_FORCED_SHUTDOWN with xfs_is_shutdown 2021-08-19 10:07:13 -07:00
xfs_icache.c New code for 5.17: 2022-01-22 11:04:27 +02:00
xfs_icache.h xfs: throttle inode inactivation queuing on memory reclaim 2021-08-09 11:13:17 -07:00
xfs_icreate_item.c xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_icreate_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_inode_item_recover.c xfs: replace xfs_sb_version checks with feature flag checks 2021-08-19 10:07:12 -07:00
xfs_inode_item.c xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_inode_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_inode.c xfs: constify the name argument to various directory functions 2022-03-14 10:23:17 -07:00
xfs_inode.h xfs: constify the name argument to various directory functions 2022-03-14 10:23:17 -07:00
xfs_ioctl32.c xfs: kill the XFS_IOC_{ALLOC,FREE}SP* ioctls 2022-01-17 09:16:41 -08:00
xfs_ioctl32.h xfs: remove unused xfs_ioctl32.h declarations 2022-01-18 10:18:36 -08:00
xfs_ioctl.c xfs: don't generate selinux audit messages for capability testing 2022-03-09 10:32:06 -08:00
xfs_ioctl.h xfs: kill the XFS_IOC_{ALLOC,FREE}SP* ioctls 2022-01-17 09:16:41 -08:00
xfs_iomap.c fsdax: shift partition offset handling into the file systems 2021-12-04 08:58:54 -08:00
xfs_iomap.h iomap: add a IOMAP_DAX flag 2021-12-04 08:58:53 -08:00
xfs_iops.c xfs: refactor user/group quota chown in xfs_setattr_nonsize 2022-03-14 10:23:17 -07:00
xfs_iops.h xfs: support idmapped mounts 2021-01-24 14:43:46 +01:00
xfs_itable.c xfs: replace xfs_sb_version checks with feature flag checks 2021-08-19 10:07:12 -07:00
xfs_itable.h xfs: support idmapped mounts 2021-01-24 14:43:46 +01:00
xfs_iwalk.c xfs: avoid buffer deadlocks when walking fs inodes 2021-08-09 11:13:16 -07:00
xfs_iwalk.h
xfs_linux.h fs: move mapping helpers 2021-12-03 18:50:17 +01:00
xfs_log_cil.c xfs: reduce kvmalloc overhead for CIL shadow buffers 2022-01-06 10:43:30 -08:00
xfs_log_priv.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_log_recover.c xfs: Remove redundant assignment of mp 2022-01-06 10:43:30 -08:00
xfs_log.c xfs: log worker needs to start before intent/unlink recovery 2022-03-20 08:59:49 -07:00
xfs_log.h xfs: AIL needs asynchronous CIL forcing 2021-08-16 12:09:30 -07:00
xfs_message.c
xfs_message.h once: implement DO_ONCE_LITE for non-fast-path "do once" functionality 2021-06-28 15:54:57 -07:00
xfs_mount.c xfs: only run COW extent recovery when there are no live extents 2021-12-21 09:49:41 -08:00
xfs_mount.h xfs: compute maximum AG btree height for critical reservation calculation 2021-10-19 11:45:15 -07:00
xfs_mru_cache.c xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_mru_cache.h
xfs_ondisk.h xfs: rename struct xfs_legacy_ictimestamp 2021-04-22 18:29:25 -07:00
xfs_pnfs.c xfs: use setattr_copy to set vfs inode attributes 2022-03-14 10:23:16 -07:00
xfs_pnfs.h
xfs_pwork.c xfs: increase the default parallelism levels of pwork clients 2021-02-03 09:18:49 -08:00
xfs_pwork.h xfs: increase the default parallelism levels of pwork clients 2021-02-03 09:18:49 -08:00
xfs_qm_bhv.c xfs: replace xfs_sb_version checks with feature flag checks 2021-08-19 10:07:12 -07:00
xfs_qm_syscalls.c xfs: fix quotaoff mutex usage now that we don't support disabling it 2021-12-21 09:49:41 -08:00
xfs_qm.c xfs: remove the xfs_dqblk_t typedef 2021-10-14 09:19:33 -07:00
xfs_qm.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_quota.h xfs: queue inactivation immediately when quota is nearing enforcement 2021-08-09 10:52:18 -07:00
xfs_quotaops.c xfs: remove the active vs running quota differentiation 2021-08-06 11:05:37 -07:00
xfs_refcount_item.c xfs: create slab caches for frequently-used deferred items 2021-10-22 16:04:36 -07:00
xfs_refcount_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_reflink.c xfs: add missing cmap->br_state = XFS_EXT_NORM update 2022-03-09 10:32:06 -08:00
xfs_reflink.h xfs: convert xfs_sb_version_has checks to use mount features 2021-08-19 10:07:14 -07:00
xfs_rmap_item.c xfs: create slab caches for frequently-used deferred items 2021-10-22 16:04:36 -07:00
xfs_rmap_item.h xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_rtalloc.c xfs: replace xfs_sb_version checks with feature flag checks 2021-08-19 10:07:12 -07:00
xfs_rtalloc.h xfs: make the record pointer passed to query_range functions const 2021-08-18 18:46:01 -07:00
xfs_stats.c xfs: periodically relog deferred intent items 2020-10-07 08:40:28 -07:00
xfs_stats.h xfs: periodically relog deferred intent items 2020-10-07 08:40:28 -07:00
xfs_super.c Bug fixes for 5.17-rc4: 2022-02-26 09:53:19 -08:00
xfs_super.h xfs: remove xfs_blkdev_issue_flush 2021-06-21 10:05:46 -07:00
xfs_symlink.c New code for 5.17: 2022-01-11 15:01:50 -08:00
xfs_symlink.h xfs: support idmapped mounts 2021-01-24 14:43:46 +01:00
xfs_sysctl.c xfs: restore speculative_cow_prealloc_lifetime sysctl 2021-02-24 10:16:08 -08:00
xfs_sysctl.h xfs: consolidate the eofblocks and cowblocks workers 2021-02-03 09:18:49 -08:00
xfs_sysfs.c xfs: sysfs: use default_groups in kobj_type 2022-01-06 10:43:30 -08:00
xfs_sysfs.h xfs: Fix UBSAN null-ptr-deref in xfs_sysfs_init 2020-08-07 11:50:17 -07:00
xfs_trace.c xfs: add trace point for fs shutdown 2021-08-18 18:46:00 -07:00
xfs_trace.h xfs: constify the name argument to various directory functions 2022-03-14 10:23:17 -07:00
xfs_trans_ail.c xfs: replace XFS_FORCED_SHUTDOWN with xfs_is_shutdown 2021-08-19 10:07:13 -07:00
xfs_trans_buf.c xfs: introduce xfs_buf_daddr() 2021-08-19 10:07:14 -07:00
xfs_trans_dquot.c xfs: rename _zone variables to _cache 2021-10-22 16:04:20 -07:00
xfs_trans_priv.h xfs: refactor adding recovered intent items to the log 2020-05-08 08:50:00 -07:00
xfs_trans.c xfs: reserve quota for dir expansion when linking/unlinking files 2022-03-14 10:23:17 -07:00
xfs_trans.h xfs: reserve quota for dir expansion when linking/unlinking files 2022-03-14 10:23:17 -07:00
xfs_xattr.c xfs: prevent metadata files from being inactivated 2021-03-25 16:47:50 -07:00
xfs.h