linux/fs/xfs
Dave Chinner 941fbdfd6d xfs: xfs_ail_push_all_sync() stalls when racing with updates
xfs_ail_push_all_sync() has a loop like this:

while max_ail_lsn {
	prepare_to_wait(ail_empty)
	target = max_ail_lsn
	wake_up(ail_task);
	schedule()
}

Which is designed to sleep until the AIL is emptied. When
xfs_ail_update_finish() moves the tail of the log, it does:

	if (list_empty(&ailp->ail_head))
		wake_up_all(&ailp->ail_empty);

So it will only wake up the sync push waiter when the AIL goes
empty. If, by the time the push waiter has woken, the AIL has more
in it, it will reset the target, wake the push task and go back to
sleep.

The problem here is that if the AIL is having items added to it
when xfs_ail_push_all_sync() is called, then they may get inserted
into the AIL at a LSN higher than the target LSN. At this point,
xfsaild_push() will see that the target is X, the item LSNs are
(X+N) and skip over them, hence never pushing the out.

The result of this the AIL will not get emptied by the AIL push
thread, hence xfs_ail_finish_update() will never see the AIL being
empty even if it moves the tail. Hence xfs_ail_push_all_sync() never
gets woken and hence cannot update the push target to capture the
items beyond the current target on the LSN.

This is a TOCTOU type of issue so the way to avoid it is to not
use the push target at all for sync pushes. We know that a sync push
is being requested by the fact the ail_empty wait queue is active,
hence the xfsaild can just set the target to max_ail_lsn on every
push that we see the wait queue active. Hence we no longer will
leave items on the AIL that are beyond the LSN sampled at the start
of a sync push.

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 xfs: refactor log recovery item sorting into a generic dispatch structure 2020-05-08 08:49:58 -07:00
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: add a xfs_inode_buftarg helper 2019-10-28 08:37:54 -07:00
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_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_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_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: remove all *_ITER_CONTINUE values 2019-08-30 22:43:56 -07:00
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: refactor ratelimited buffer error messages into helper 2020-05-07 08:27:46 -07:00
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: xfs_ail_push_all_sync() stalls when racing with updates 2022-03-20 08:59:49 -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