diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 996b3314f4..fcdf7af8e6 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1320,6 +1320,7 @@ static bool cluster_needs_new_alloc(BlockDriverState *bs, uint64_t l2_entry)
         if (l2_entry & QCOW_OFLAG_COPIED) {
             return false;
         }
+        /* fallthrough */
     case QCOW2_CLUSTER_UNALLOCATED:
     case QCOW2_CLUSTER_COMPRESSED:
     case QCOW2_CLUSTER_ZERO_PLAIN: