diff --git a/kernel-shared/backref.c b/kernel-shared/backref.c
index 89ccf073..f46f3267 100644
--- a/kernel-shared/backref.c
+++ b/kernel-shared/backref.c
@@ -650,7 +650,8 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
 			break;
 		}
 		default:
-			WARN_ON(1);
+			error("invalid backref type: %u", type);
+			ret = -EUCLEAN;
 		}
 		if (ret)
 			return ret;