btrfs: use btrfs_record_snapshot_destroy() during rmdir

[ Upstream commit 157501b0469969fc1ba53add5049575aadd79d80 ]

We are setting the parent directory's last_unlink_trans directly which
may result in a concurrent task starting to log the directory not see the
update and therefore can log the directory after we removed a child
directory which had a snapshot within instead of falling back to a
transaction commit. Replaying such a log tree would result in a mount
failure since we can't currently delete snapshots (and subvolumes) during
log replay. This is the type of failure described in commit 1ec9a1ae1e30
("Btrfs: fix unreplayable log after snapshot delete + parent dir fsync").

Fix this by using btrfs_record_snapshot_destroy() which updates the
last_unlink_trans field while holding the inode's log_mutex lock.

Fixes: 44f714dae50a ("Btrfs: improve performance on fsync against new inode after rename/unlink")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8f92f998dc37bd67dbd744247d7169fd18125a2d..757111e529948262e4104ef0805c9bdc38cf238d 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4772,7 +4772,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
         * deletes for directory foo.
         */
        if (BTRFS_I(inode)->last_unlink_trans >= trans->transid)
-               BTRFS_I(dir)->last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
+               btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
 
        if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
                err = btrfs_unlink_subvol(trans, dir, dentry);