btrfs: do not BUG_ON() on failure to reserve metadata for delayed item

At btrfs_insert_delayed_dir_index(), we don't expect the metadata
reservation for the delayed dir index item insertion to fail, because the
caller is supposed to have reserved 1 unit of metadata space for that.
All callers are able to deal with an error in case that happens, so there
is no need for something so drastic as a BUG_ON() in case of failure.
Instead just emit a warning, so that's easily noticed during development
(fstests in particular), and return the error to the caller.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index d9be90ac7c3a38d036ba8ba73c548dc836c2c0b0..6019c35de8de00a5ec51f962d0d89690fa6fa5d0 100644 (file)
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1386,10 +1386,13 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 
        ret = btrfs_delayed_item_reserve_metadata(trans, dir->root, delayed_item);
        /*
-        * we have reserved enough space when we start a new transaction,
-        * so reserving metadata failure is impossible
+        * Space was reserved for a dir index item insertion when we started the
+        * transaction, so getting a failure here should be impossible.
         */
-       BUG_ON(ret);
+       if (WARN_ON(ret)) {
+               btrfs_release_delayed_item(delayed_item);
+               goto release_node;
+       }
 
        mutex_lock(&delayed_node->mutex);
        ret = __btrfs_add_delayed_insertion_item(delayed_node, delayed_item);