Commit 4ed3e0c4 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Kevin Wolf
Browse files

block/qcow: use buffer-based io 



Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent b00cb15b

block/qcow.c

+6 −13
Original line number Diff line number Diff line
@@ -631,7 +631,6 @@ static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset, 
    int offset_in_cluster;

    int ret = 0, n;

    uint64_t cluster_offset;

    QEMUIOVector hd_qiov;

    uint8_t *buf;

    void *orig_buf;
@@ -663,11 +662,10 @@ static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset, 
        if (!cluster_offset) {

            if (bs->backing) {

                /* read from the base image */

                qemu_iovec_init_buf(&hd_qiov, buf, n);

                qemu_co_mutex_unlock(&s->lock);

                /* qcow2 emits this on bs->file instead of bs->backing */

                BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);

                ret = bdrv_co_preadv(bs->backing, offset, n, &hd_qiov, 0);

                ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);

                qemu_co_mutex_lock(&s->lock);

                if (ret < 0) {

                    break;
@@ -688,11 +686,10 @@ static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset, 
                ret = -EIO;

                break;

            }

            qemu_iovec_init_buf(&hd_qiov, buf, n);

            qemu_co_mutex_unlock(&s->lock);

            BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);

            ret = bdrv_co_preadv(bs->file, cluster_offset + offset_in_cluster,

                                 n, &hd_qiov, 0);

            ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,

                                n, buf, 0);

            qemu_co_mutex_lock(&s->lock);

            if (ret < 0) {

                break;
@@ -731,7 +728,6 @@ static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, uint64_t offset, 
    int offset_in_cluster;

    uint64_t cluster_offset;

    int ret = 0, n;

    QEMUIOVector hd_qiov;

    uint8_t *buf;

    void *orig_buf;
@@ -776,11 +772,10 @@ static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, uint64_t offset, 
            }

        }



        qemu_iovec_init_buf(&hd_qiov, buf, n);

        qemu_co_mutex_unlock(&s->lock);

        BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);

        ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster,

                              n, &hd_qiov, 0);

        ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,

                             n, buf, 0);

        qemu_co_mutex_lock(&s->lock);

        if (ret < 0) {

            break;
@@ -1056,7 +1051,6 @@ qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 
                           uint64_t bytes, QEMUIOVector *qiov)

{

    BDRVQcowState *s = bs->opaque;

    QEMUIOVector hd_qiov;

    z_stream strm;

    int ret, out_len;

    uint8_t *buf, *out_buf;
@@ -1122,9 +1116,8 @@ qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 
    }

    cluster_offset &= s->cluster_offset_mask;



    qemu_iovec_init_buf(&hd_qiov, out_buf, out_len);

    BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);

    ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);

    ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);

    if (ret < 0) {

        goto fail;

    }