From patchwork Tue May 22 16:17:12 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 160682 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5D1ABB6FA5 for ; Wed, 23 May 2012 02:17:58 +1000 (EST) Received: from localhost ([::1]:42366 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWrmW-0007ZZ-1d for incoming@patchwork.ozlabs.org; Tue, 22 May 2012 12:17:56 -0400 Received: from eggs.gnu.org ([208.118.235.92]:45759) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWrmD-0007Il-Eu for qemu-devel@nongnu.org; Tue, 22 May 2012 12:17:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SWrmB-0001Zc-Nt for qemu-devel@nongnu.org; Tue, 22 May 2012 12:17:37 -0400 Received: from mail-pz0-f45.google.com ([209.85.210.45]:34090) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWrmB-0001ZD-FC for qemu-devel@nongnu.org; Tue, 22 May 2012 12:17:35 -0400 Received: by dadv2 with SMTP id v2so10214735dad.4 for ; Tue, 22 May 2012 09:17:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; bh=pC6BeN6a+96uTeavdv+QSys/7lpxiv5UCXDO/Ha4H4Y=; b=kLZRcBpN7MhYsCJBqBcSJJwutcF6BSYkVf6a+1pUP1KuLidamipQqXSaTyNmWT+5gm H7CvGLS22v3LyoC83Vtw5HinbRajbxmkjrEjTeD/Yk58h1X0ojZNdxJjlWvThOPyJtHH HchP9su23G9iwvTxsBnN5FHyMqZrdLFQKsTZWw5NY7q+VMVpmvrFIeIONlb7g4GWHDlX pok+kJZaJovUSL7hYlCXSN7gbt0HiZBuYjiNhyk1rLANjLtrZharxw5NWxcjAWZ+Kw5/ NMtpmXpcMJWvEDSjP9QQcGhb2+afHECFvkQRMURtyWoieWB/+A3Fb/vCmZpWapdcFwXE jF1Q== Received: by 10.68.242.99 with SMTP id wp3mr294412pbc.21.1337703453461; Tue, 22 May 2012 09:17:33 -0700 (PDT) Received: from yakj.usersys.redhat.com (93-34-182-16.ip50.fastwebnet.it. [93.34.182.16]) by mx.google.com with ESMTPS id ix5sm27148143pbc.18.2012.05.22.09.17.30 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 22 May 2012 09:17:32 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Tue, 22 May 2012 18:17:12 +0200 Message-Id: <1337703438-9764-2-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.7.10.1 In-Reply-To: <1337703438-9764-1-git-send-email-pbonzini@redhat.com> References: <1337703438-9764-1-git-send-email-pbonzini@redhat.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.85.210.45 Cc: kwolf@redhat.com Subject: [Qemu-devel] [PATCH 1.2 1/7] block: flush in writethrough mode after writes 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 We want to make the formats handle their own flushes autonomously, while keeping for guests the ability to use a writethrough cache. Since formats will write metadata via bs->file, bdrv_co_do_writev is the only place where we need to add a flush. Signed-off-by: Paolo Bonzini --- block.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index af2ab4f..7add33c 100644 --- a/block.c +++ b/block.c @@ -1747,8 +1747,8 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, return ret; } - /* No flush needed for cache modes that use O_DSYNC */ - if ((bs->open_flags & BDRV_O_CACHE_WB) != 0) { + /* No flush needed for cache modes that already do it */ + if (bs->enable_write_cache) { bdrv_flush(bs); } @@ -1797,6 +1797,9 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, cluster_nb_sectors); } else { + /* This does not change the data on the disk, it is not necessary + * to flush even in cache=writethrough mode. + */ ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, &bounce_qiov); } @@ -1966,6 +1969,10 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); } + if (ret == 0 && !bs->enable_write_cache) { + ret = bdrv_co_flush(bs); + } + if (bs->dirty_bitmap) { set_dirty_bitmap(bs, sector_num, nb_sectors, 1); }