If the flag BDRV_REQ_PREFETCH was set, pass it further to the COR-driver to skip unneeded reading. It can be taken into account for the COR-algorithms optimization. That check is being made during the block stream job by the moment.
Signed-off-by: Andrey Shinkevich <andrey.shinkev...@virtuozzo.com> --- block/copy-on-read.c | 14 ++++++++++---- block/io.c | 2 +- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/block/copy-on-read.c b/block/copy-on-read.c index f53f7e0..5389dca 100644 --- a/block/copy-on-read.c +++ b/block/copy-on-read.c @@ -145,10 +145,16 @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs, } } - ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, - local_flags); - if (ret < 0) { - return ret; + if ((flags & BDRV_REQ_PREFETCH) & + !(local_flags & BDRV_REQ_COPY_ON_READ)) { + /* Skip non-guest reads if no copy needed */ + } else { + + ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, + local_flags); + if (ret < 0) { + return ret; + } } offset += n; diff --git a/block/io.c b/block/io.c index 11df188..62b75a5 100644 --- a/block/io.c +++ b/block/io.c @@ -1388,7 +1388,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum); ret = bdrv_driver_preadv(bs, cluster_offset, pnum, - &local_qiov, 0, 0); + &local_qiov, 0, flags & BDRV_REQ_PREFETCH); if (ret < 0) { goto err; } -- 1.8.3.1