[PATCH v2] btrfs: add missing check after link_free_space

[Dinghao Liu]

The return value of link_free_space is checked out-sync.
One branch of an if statement uses an extra check after
WARN_ON() but its peer branch does not. WARN_ON() does
not change the control flow, thus only using this check
might be insufficient.

Fix this by simply adding a check on ret.

Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
--
Changes in v2:
  - Add memory free for free space entry.
---
 fs/btrfs/free-space-cache.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 3283da419200..ba2e6cea5233 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2437,6 +2437,10 @@ int btrfs_remove_free_space(struct btrfs_block_group *block_group,
 			if (info->bytes) {
 				ret = link_free_space(ctl, info);
 				WARN_ON(ret);
+				if (ret) {
+					kmem_cache_free(btrfs_free_space_cachep, info);
+					goto out_lock;
+				}
 			} else {
 				kmem_cache_free(btrfs_free_space_cachep, info);
 			}
-- 
2.21.0 (Apple Git-122)