fscache: add missing unlock

index c598ea4..6980902 100644
@@ -881,6 +881,7 @@ submit_failed:
 	goto nobufs;
 
 nobufs_unlock_obj:
+	spin_unlock(&cookie->stores_lock);
 	spin_unlock(&object->lock);
 nobufs:
 	spin_unlock(&cookie->lock);