From patchwork Mon Jun 8 05:56:09 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 481789 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 17A941401AB for ; Mon, 8 Jun 2015 15:57:45 +1000 (AEST) Received: from localhost ([::1]:56027 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z1q47-0001wf-4E for incoming@patchwork.ozlabs.org; Mon, 08 Jun 2015 01:57:43 -0400 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 Received: from mx1.redhat.com ([209.132.183.28]:44377) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z1q33-0000By-6v; Mon, 08 Jun 2015 01:56:37 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id BC3478F276; Mon, 8 Jun 2015 05:56:36 +0000 (UTC) Received: from ad.nay.redhat.com (dhcp-14-104.nay.redhat.com [10.66.14.104]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t585uEsS007462; Mon, 8 Jun 2015 01:56:33 -0400 From: Fam Zheng To: qemu-devel@nongnu.org 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> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , qemu-block@nongnu.org, Jeff Cody , qemu-stable@nongnu.org, Stefan Hajnoczi , pbonzini@redhat.com, jsnow@redhat.com, wangxiaolong@ucloud.cn Subject: [Qemu-devel] [PATCH v7 3/8] mirror: Do zero write on target if sectors not allocated X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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; }