When Filipe added the recursive directory logging stuff 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.
Signed-off-by: Josef Bacik <jo...@toxicpanda.com>
---
fs/btrfs/tree-log.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index f06454a55e00..bccb62c1c587 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -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;
/*
--
2.14.3
