Commit 1143ec5e authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Stefan Hajnoczi
Browse files

block/io: bdrv_co_do_copy_on_readv: use and support qiov_offset 



Use and support new API in bdrv_co_do_copy_on_readv. Note that in case
of allocated-in-top we need to shrink read size to MIN(..) by hand, as
pre-patch this was actually done implicitly by qemu_iovec_concat (and
we used local_qiov.size).

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-6-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-6-vsementsov@virtuozzo.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent ac850bf0

block/io.c

+9 −9
Original line number Diff line number Diff line
@@ -1227,7 +1227,7 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 


static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,

        int64_t offset, unsigned int bytes, QEMUIOVector *qiov,

        int flags)

        size_t qiov_offset, int flags)

{

    BlockDriverState *bs = child->bs;
@@ -1239,7 +1239,6 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, 
    void *bounce_buffer;



    BlockDriver *drv = bs->drv;

    QEMUIOVector local_qiov;

    int64_t cluster_offset;

    int64_t cluster_bytes;

    size_t skip_bytes;
@@ -1302,6 +1301,8 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, 
        assert(skip_bytes < pnum);



        if (ret <= 0) {

            QEMUIOVector local_qiov;



            /* Must copy-on-read; use the bounce buffer */

            pnum = MIN(pnum, MAX_BOUNCE_BUFFER);

            qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
@@ -1339,16 +1340,15 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, 
            }



            if (!(flags & BDRV_REQ_PREFETCH)) {

                qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes,

                qemu_iovec_from_buf(qiov, qiov_offset + progress,

                                    bounce_buffer + skip_bytes,

                                    pnum - skip_bytes);

            }

        } else if (!(flags & BDRV_REQ_PREFETCH)) {

            /* Read directly into the destination */

            qemu_iovec_init(&local_qiov, qiov->niov);

            qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);

            ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,

                                     &local_qiov, 0, 0);

            qemu_iovec_destroy(&local_qiov);

            ret = bdrv_driver_preadv(bs, offset + progress,

                                     MIN(pnum - skip_bytes, bytes - progress),

                                     qiov, qiov_offset + progress, 0);

            if (ret < 0) {

                goto err;

            }
@@ -1422,7 +1422,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, 
        }



        if (!ret || pnum != bytes) {

            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, flags);

            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, 0, flags);

            goto out;

        } else if (flags & BDRV_REQ_PREFETCH) {

            goto out;