Re: [PATCH] virtio-blk: Fix zone append sector reporting in batched completion

[Michael S. Tsirkin]

On Mon, Oct 26, 2026 at 07:55:19PM +0800, shao.mingyin@xxxxxxxxxx wrote:
> From: Shao Mingyin <shao.mingyin@xxxxxxxxxx>
> 
> For zone append, the block layer copies req->__sector back into the
> bio in blk_zone_append_update_request_bio(), so the driver must update
> req->__sector with the sector reported by the device.
> virtblk_request_done() does that, but the batched completion path used
> by virtblk_poll() only unmaps and cleans up the requests before calling
> blk_mq_end_request_batch().
> 
> A zone append completed through polling therefore keeps the sector that
> was assigned at submission time, and the file system or application sees
> the wrong LBA for the written data.
> 
> Move the sector update into a helper and call it from both completion
> paths.
> 
> Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices")
> Signed-off-by: Shao Mingyin <shao.mingyin@xxxxxxxxxx>

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

> ---
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index c8bfbf8435ac..cc29b8238a4d 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -331,18 +331,25 @@ static inline u8 virtblk_vbr_status(struct virtblk_req *vbr)
>  	return *((u8 *)&vbr->in_hdr + vbr->in_hdr_len - 1);
>  }
> 
> +static inline void virtblk_update_zone_append_sector(struct request *req,
> +						     struct virtblk_req *vbr)
> +{
> +	struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
> +
> +	if (req_op(req) == REQ_OP_ZONE_APPEND)
> +		req->__sector = virtio64_to_cpu(vblk->vdev,
> +						vbr->in_hdr.zone_append.sector);
> +}
> +
>  static inline void virtblk_request_done(struct request *req)
>  {
>  	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
>  	blk_status_t status = virtblk_result(virtblk_vbr_status(vbr));
> -	struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
> 
>  	virtblk_unmap_data(req, vbr);
>  	virtblk_cleanup_cmd(req);
> 
> -	if (req_op(req) == REQ_OP_ZONE_APPEND)
> -		req->__sector = virtio64_to_cpu(vblk->vdev,
> -						vbr->in_hdr.zone_append.sector);
> +	virtblk_update_zone_append_sector(req, vbr);
> 
>  	blk_mq_end_request(req, status);
>  }
> @@ -1196,8 +1203,11 @@ static void virtblk_complete_batch(struct io_comp_batch *iob)
>  	struct request *req;
> 
>  	rq_list_for_each(&iob->req_list, req) {
> -		virtblk_unmap_data(req, blk_mq_rq_to_pdu(req));
> +		struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
> +
> +		virtblk_unmap_data(req, vbr);
>  		virtblk_cleanup_cmd(req);
> +		virtblk_update_zone_append_sector(req, vbr);
>  	}
>  	blk_mq_end_request_batch(iob);
>  }