+static coroutine_fn int replication_co_writev(BlockDriverState *bs,
+ int64_t sector_num,
+ int remaining_sectors,
+ QEMUIOVector *qiov)
+{
+ BDRVReplicationState *s = bs->opaque;
+ QEMUIOVector hd_qiov;
+ uint64_t bytes_done = 0;
+ BdrvChild *top = bs->file;
+ BdrvChild *base = s->secondary_disk;
+ BlockDriverState *target;
+ int ret, n;
+
+ ret = replication_get_io_status(s);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (ret == 0) {
+ ret = bdrv_co_writev(top->bs, sector_num,
+ remaining_sectors, qiov);
+ return replication_return_value(s, ret);
+ }
+
+ /*
+ * Failover failed, only write to active disk if the sectors
+ * have already been allocated in active disk/hidden disk.
+ */
+ qemu_iovec_init(&hd_qiov, qiov->niov);
+ while (remaining_sectors > 0) {
+ ret = bdrv_is_allocated_above(top->bs, base->bs, sector_num,
+ remaining_sectors, &n);
+ if (ret < 0) {
+ return ret;
+ }
+
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done, n * BDRV_SECTOR_SIZE);
+
+ target = ret ? (top->bs) : (base->bs);
+ ret = bdrv_co_writev(target, sector_num, n, &hd_qiov);
+ if (ret < 0) {
+ return ret;
+ }
+
+ remaining_sectors -= n;
+ sector_num += n;
+ bytes_done += n * BDRV_SECTOR_SIZE;
+ }
+
+ return 0;