VIRTIO_BLK_T_DISCARD
type = VIRTIO_BLK_T_DISCARD;
if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES ||
case VIRTIO_BLK_T_DISCARD:
if (type == VIRTIO_BLK_T_DISCARD && flags != 0) {