static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start) { BDRVQcow2State *s = bs->opaque; int nr = s->cluster_sectors; uint64_t off; int ret; ret = qcow2_get_cluster_offset(bs, start << BDRV_SECTOR_BITS, &nr, &off); assert(nr == s->cluster_sectors); return ret == QCOW2_CLUSTER_UNALLOCATED || ret == QCOW2_CLUSTER_ZERO; }