From: Josef Bacik Date: Wed, 6 Mar 2019 22:13:04 +0000 (-0500) Subject: btrfs: remove WARN_ON in log_dir_items X-Git-Tag: v4.19.33~89 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b57220cc982033dc8e1e8d398cb006b72b275213;p=platform%2Fkernel%2Flinux-rpi.git btrfs: remove WARN_ON in log_dir_items commit 2cc8334270e281815c3850c3adea363c51f21e0d upstream. When Filipe added the recursive directory logging stuff in 2f2ff0ee5e430 ("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 Signed-off-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index b08c47a..5af65d5 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -3532,9 +3532,16 @@ 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; /*