virtio_blk_submit_multireq() fuses adjacent in-zone writes into a single request. On a zoned backend, a merged zone append request that straddles a zone boundary is rejected by the device because each write must stay within a single zone.
Add a bail condition to the merge coalescer: if combining the candidate request into the current batch would cross a zone boundary, flush the current batch and start a new one. Signed-off-by: Sam Li <[email protected]> --- hw/block/virtio-blk.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 9cb9f1fb2b..285db19ac7 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -288,6 +288,9 @@ static void virtio_blk_submit_multireq(VirtIOBlock *s, MultiReqBuffer *mrb) int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0; uint32_t max_transfer; int64_t sector_num = 0; + BlockDriverState *bs = blk_bs(s->blk); + bool zone_cross; + int64_t zone_sector, end_sector; if (mrb->num_reqs == 1) { submit_requests(s, mrb, 0, 1, -1); @@ -303,17 +306,34 @@ static void virtio_blk_submit_multireq(VirtIOBlock *s, MultiReqBuffer *mrb) for (i = 0; i < mrb->num_reqs; i++) { VirtIOBlockReq *req = mrb->reqs[i]; if (num_reqs > 0) { + zone_cross = false; + + /* + * On zoned backends, a single backend write must not span a zone + * boundary. Bail out of merging if combining req into the current + * batch would straddle a zone. + */ + if (bs && bs->bl.zone_size > 0) { + zone_sector = bs->bl.zone_size / BDRV_SECTOR_SIZE; + end_sector = req->sector_num + + req->qiov.size / BDRV_SECTOR_SIZE - 1; + zone_cross = (sector_num / zone_sector) != + (end_sector / zone_sector); + } + /* * NOTE: We cannot merge the requests in below situations: * 1. requests are not sequential * 2. merge would exceed maximum number of IOVs * 3. merge would exceed maximum transfer length of backend device + * 4. merge would cross a zone boundary on a zoned backend */ if (sector_num + nb_sectors != req->sector_num || niov > blk_get_max_iov(s->blk) - req->qiov.niov || req->qiov.size > max_transfer || nb_sectors > (max_transfer - - req->qiov.size) / BDRV_SECTOR_SIZE) { + req->qiov.size) / BDRV_SECTOR_SIZE || + zone_cross) { submit_requests(s, mrb, start, num_reqs, niov); num_reqs = 0; } -- 2.53.0
