From patchwork Tue Feb 18 12:11:16 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Beno=C3=AEt_Canet?= X-Patchwork-Id: 321419 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 E07C12C00B7 for ; Tue, 18 Feb 2014 23:12:25 +1100 (EST) Received: from localhost ([::1]:48519 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WFjXD-00055O-I4 for incoming@patchwork.ozlabs.org; Tue, 18 Feb 2014 07:12:23 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37435) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WFjWU-00051q-Nc for qemu-devel@nongnu.org; Tue, 18 Feb 2014 07:11:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WFjWO-0004mI-J0 for qemu-devel@nongnu.org; Tue, 18 Feb 2014 07:11:38 -0500 Received: from lnantes-156-75-100-125.w80-12.abo.wanadoo.fr ([80.12.84.125]:33561 helo=paradis.irqsave.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WFjWO-0004lX-8q for qemu-devel@nongnu.org; Tue, 18 Feb 2014 07:11:32 -0500 Received: from localhost.localdomain (laure.irqsave.net [192.168.77.2]) by paradis.irqsave.net (Postfix) with ESMTP id CFA2E657E6; Tue, 18 Feb 2014 13:51:36 +0100 (CET) From: =?UTF-8?q?Beno=C3=AEt=20Canet?= To: qemu-devel@nongnu.org Date: Tue, 18 Feb 2014 13:11:16 +0100 Message-Id: <1392725487-18330-2-git-send-email-benoit.canet@irqsave.net> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1392725487-18330-1-git-send-email-benoit.canet@irqsave.net> References: <1392725487-18330-1-git-send-email-benoit.canet@irqsave.net> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 80.12.84.125 Cc: kwolf@redhat.com, famz@redhat.com, =?UTF-8?q?Beno=C3=AEt=20Canet?= , mreitz@redhat.com, stefanha@redhat.com Subject: [Qemu-devel] [PATCH V18 01/12] quorum: Create quorum.c, add QuorumChildRequest and QuorumAIOCB. 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: Benoît Canet Quorum is a block filter mirroring writes to num_children children. For reads quorum reads each children and does a vote. If more than vote_threshold versions are identical the quorum is reached and this winning version is returned to the guest. So quorum prevents bit corruption. For high availability purpose minority errors are reported via QMP but the guest does not see them. This patch creates the driver C source file and introduces the structures that will be used in asynchronous reads and writes. Signed-off-by: Benoit Canet Reviewed-by: Max Reitz --- block/Makefile.objs | 1 + block/quorum.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 54 insertions(+) create mode 100644 block/quorum.c diff --git a/block/Makefile.objs b/block/Makefile.objs index e254a21..716556f 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -3,6 +3,7 @@ block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-c block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o block-obj-y += qed-check.o block-obj-$(CONFIG_VHDX) += vhdx.o vhdx-endian.o vhdx-log.o +block-obj-y += quorum.o block-obj-y += parallels.o blkdebug.o blkverify.o block-obj-y += snapshot.o qapi.o block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o diff --git a/block/quorum.c b/block/quorum.c new file mode 100644 index 0000000..950f5cc --- /dev/null +++ b/block/quorum.c @@ -0,0 +1,53 @@ +/* + * Quorum Block filter + * + * Copyright (C) 2012-2014 Nodalink, EURL. + * + * Author: + * Benoît Canet + * + * Based on the design and code of blkverify.c (Copyright (C) 2010 IBM, Corp) + * and blkmirror.c (Copyright (C) 2011 Red Hat, Inc). + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "block/block_int.h" + +typedef struct QuorumAIOCB QuorumAIOCB; + +/* Quorum will create one instance of the following structure per operation it + * performs on its children. + * So for each read/write operation coming from the upper layer there will be + * $children_count QuorumChildRequest. + */ +typedef struct QuorumChildRequest { + BlockDriverAIOCB *aiocb; + QEMUIOVector qiov; + uint8_t *buf; + int ret; + QuorumAIOCB *parent; +} QuorumChildRequest; + +/* Quorum will use the following structure to track progress of each read/write + * operation received by the upper layer. + * This structure hold pointers to the QuorumChildRequest structures instances + * used to do operations on each children and track overall progress. + */ +struct QuorumAIOCB { + BlockDriverAIOCB common; + + /* Request metadata */ + uint64_t sector_num; + int nb_sectors; + + QEMUIOVector *qiov; /* calling IOV */ + + QuorumChildRequest *qcrs; /* individual child requests */ + int count; /* number of completed AIOCB */ + int success_count; /* number of successfully completed AIOCB */ + + bool is_read; + int vote_ret; +};