From patchwork Thu Jul 2 09:19:41 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 490533 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 0DFB91402A0 for ; Thu, 2 Jul 2015 19:24:25 +1000 (AEST) Received: from localhost ([::1]:35473 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZAajG-0000ho-Kc for incoming@patchwork.ozlabs.org; Thu, 02 Jul 2015 05:24:22 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53827) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZAafd-0002FN-HY for qemu-devel@nongnu.org; Thu, 02 Jul 2015 05:20:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZAafc-0000WD-A8 for qemu-devel@nongnu.org; Thu, 02 Jul 2015 05:20:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33674) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZAafc-0000W6-5f for qemu-devel@nongnu.org; Thu, 02 Jul 2015 05:20:36 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id DB6CA8E78D; Thu, 2 Jul 2015 09:20:35 +0000 (UTC) Received: from localhost (ovpn-112-49.ams2.redhat.com [10.36.112.49]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t629KXJZ018294; Thu, 2 Jul 2015 05:20:35 -0400 From: Stefan Hajnoczi To: Date: Thu, 2 Jul 2015 10:19:41 +0100 Message-Id: <1435828789-9647-10-git-send-email-stefanha@redhat.com> In-Reply-To: <1435828789-9647-1-git-send-email-stefanha@redhat.com> References: <1435828789-9647-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , Peter Maydell , Fam Zheng , Stefan Hajnoczi Subject: [Qemu-devel] [PULL 09/17] 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 From: Fam Zheng 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 Signed-off-by: Stefan Hajnoczi --- block/mirror.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 4be06a5..8888cea 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -165,6 +165,8 @@ 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) { @@ -291,8 +293,22 @@ 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; }