From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33171) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z1q36-0008EB-AK for qemu-devel@nongnu.org; Mon, 08 Jun 2015 01:56:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z1q35-0000Cc-Fu for qemu-devel@nongnu.org; Mon, 08 Jun 2015 01:56:40 -0400 From: Fam Zheng Date: Mon, 8 Jun 2015 13:56:09 +0800 Message-Id: <1433742974-20128-4-git-send-email-famz@redhat.com> In-Reply-To: <1433742974-20128-1-git-send-email-famz@redhat.com> References: <1433742974-20128-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v7 3/8] mirror: Do zero write on target if sectors not allocated List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, Jeff Cody , qemu-stable@nongnu.org, Stefan Hajnoczi , pbonzini@redhat.com, jsnow@redhat.com, wangxiaolong@ucloud.cn If guest discards a source cluster, mirroring with bdrv_aio_readv is overkill. Some protocols do zero upon discard, where it's best to use bdrv_aio_write_zeroes, otherwise, bdrv_aio_discard will be enough. Signed-off-by: Fam Zheng --- block/mirror.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index d2515c7..3c38695 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -164,6 +164,8 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; uint64_t delay_ns = 0; MirrorOp *op; + int pnum; + int64_t ret; s->sector_num = hbitmap_iter_next(&s->hbi); if (s->sector_num < 0) { @@ -290,8 +292,22 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) s->in_flight++; s->sectors_in_flight += nb_sectors; trace_mirror_one_iteration(s, sector_num, nb_sectors); - bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, - mirror_read_complete, op); + + ret = bdrv_get_block_status_above(source, NULL, sector_num, + nb_sectors, &pnum); + if (ret < 0 || pnum < nb_sectors || + (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { + bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, + mirror_read_complete, op); + } else if (ret & BDRV_BLOCK_ZERO) { + bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, + s->unmap ? BDRV_REQ_MAY_UNMAP : 0, + mirror_write_complete, op); + } else { + assert(!(ret & BDRV_BLOCK_DATA)); + bdrv_aio_discard(s->target, sector_num, op->nb_sectors, + mirror_write_complete, op); + } return delay_ns; } -- 2.4.2