diff options
| author | Filipe Manana | 2022-09-08 12:31:50 +0100 |
|---|---|---|
| committer | David Sterba | 2022-09-13 14:05:08 +0200 |
| commit | 8a1f1e3d1eecf9d2359a2709e276743a67e145db (patch) | |
| tree | d1e4b2b6da17904cddb079e168ffde3bf04e4916 /fs | |
| parent | 5da431b71d4b9be3c8cf6786eff9e2d41a5f9f65 (diff) | |
btrfs: fix hang during unmount when stopping block group reclaim worker
During early unmount, at close_ctree(), we try to stop the block group
reclaim task with cancel_work_sync(), but that may hang if the block group
reclaim task is currently at btrfs_relocate_block_group() waiting for the
flag BTRFS_FS_UNFINISHED_DROPS to be cleared from fs_info->flags. During
unmount we only clear that flag later, after trying to stop the block
group reclaim task.
Fix that by clearing BTRFS_FS_UNFINISHED_DROPS before trying to stop the
block group reclaim task and after setting BTRFS_FS_CLOSING_START, so that
if the reclaim task is waiting on that bit, it will stop immediately after
being woken, because it sees the filesystem is closing (with a call to
btrfs_fs_closing()), and then returns immediately with -EINTR.
Fixes: 31e70e527806c5 ("btrfs: fix hang during unmount when block group reclaim task is running")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/disk-io.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 129711773ae5..9f844328b1e2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4477,6 +4477,17 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info) set_bit(BTRFS_FS_CLOSING_START, &fs_info->flags); /* + * If we had UNFINISHED_DROPS we could still be processing them, so + * clear that bit and wake up relocation so it can stop. + * We must do this before stopping the block group reclaim task, because + * at btrfs_relocate_block_group() we wait for this bit, and after the + * wait we stop with -EINTR if btrfs_fs_closing() returns non-zero - we + * have just set BTRFS_FS_CLOSING_START, so btrfs_fs_closing() will + * return 1. + */ + btrfs_wake_unfinished_drop(fs_info); + + /* * We may have the reclaim task running and relocating a data block group, * in which case it may create delayed iputs. So stop it before we park * the cleaner kthread otherwise we can get new delayed iputs after @@ -4494,12 +4505,6 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info) */ kthread_park(fs_info->cleaner_kthread); - /* - * If we had UNFINISHED_DROPS we could still be processing them, so - * clear that bit and wake up relocation so it can stop. - */ - btrfs_wake_unfinished_drop(fs_info); - /* wait for the qgroup rescan worker to stop */ btrfs_qgroup_wait_for_completion(fs_info, false); |