[PATCH 5.4 154/214] btrfs: check the right error variable in btrfs_del_dir_entries_in_log

Greg Kroah-Hartman
2020-09-01T16:20:07Z

From: Josef Bacik <josef@toxicpanda.com>

commit fb2fecbad50964b9f27a3b182e74e437b40753ef upstream.

With my new locking code dbench is so much faster that I tripped over a
transaction abort from ENOSPC. This turned out to be because
btrfs_del_dir_entries_in_log was checking for ret == -ENOSPC, but this
function sets err on error, and returns err. So instead of properly
marking the inode as needing a full commit, we were returning -ENOSPC
and aborting in __btrfs_unlink_inode. Fix this by checking the proper
variable so that we return the correct thing in the case of ENOSPC.

The ENOENT needs to be checked, because btrfs_lookup_dir_item_index()
can return -ENOENT if the dir item isn't in the tree log (which would
happen if we hadn't fsync'ed this guy). We actually handle that case in
__btrfs_unlink_inode, so it's an expected error to get back.

Fixes: 4a500fd178c8 ("Btrfs: Metadata ENOSPC handling for tree log")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note and comment about ENOENT ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/tree-log.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3473,11 +3473,13 @@ fail:
btrfs_free_path(path);
out_unlock:
mutex_unlock(&dir->log_mutex);
- if (ret == -ENOSPC) {
+ if (err == -ENOSPC) {
btrfs_set_log_full_commit(trans);
- ret = 0;
- } else if (ret < 0)
- btrfs_abort_transaction(trans, ret);
+ err = 0;
+ } else if (err < 0 && err != -ENOENT) {
+ /* ENOENT can be returned if the entry hasn't been fsynced yet */
+ btrfs_abort_transaction(trans, err);
+ }

btrfs_end_log_trans(root);