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btrfs: remove WARN_ON in log_dir_items 

When Filipe added the recursive directory logging stuff in
2f2ff0ee5e ("Btrfs: fix metadata inconsistencies after directory
fsync") he specifically didn't take the directory i_mutex for the
children directories that we need to log because of lockdep.  This is
generally fine, but can lead to this WARN_ON() tripping if we happen to
run delayed deletion's in between our first search and our second search
of dir_item/dir_indexes for this directory.  We expect this to happen,
so the WARN_ON() isn't necessary.  Drop the WARN_ON() and add a comment
so we know why this case can happen.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Josef Bacik 2019-03-06 17:13:04 -05:00 committed by David Sterba
parent bf504110bc
commit 2cc8334270
1 changed files with 9 additions and 2 deletions
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11
fs/btrfs/tree-log.c
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@ -3578,9 +3578,16 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
}
btrfs_release_path(path);
/* find the first key from this transaction again */
/*
* Find the first key from this transaction again. See the note for
* log_new_dir_dentries, if we're logging a directory recursively we
* won't be holding its i_mutex, which means we can modify the directory
* while we're logging it. If we remove an entry between our first
* search and this search we'll not find the key again and can just
* bail.
*/
ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
if (WARN_ON(ret != 0))
if (ret != 0)
goto done;
/*