From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52285) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WGyM2-0002wr-Fy for qemu-devel@nongnu.org; Fri, 21 Feb 2014 17:14:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WGyLx-0000fo-FQ for qemu-devel@nongnu.org; Fri, 21 Feb 2014 17:13:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41412) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WGyLx-0000fZ-6q for qemu-devel@nongnu.org; Fri, 21 Feb 2014 17:13:53 -0500 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s1LMDpP4028403 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 21 Feb 2014 17:13:52 -0500 From: Kevin Wolf Date: Fri, 21 Feb 2014 23:12:38 +0100 Message-Id: <1393020771-32712-42-git-send-email-kwolf@redhat.com> In-Reply-To: <1393020771-32712-1-git-send-email-kwolf@redhat.com> References: <1393020771-32712-1-git-send-email-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 41/54] quorum: Create quorum.c, add QuorumChildRequest and QuorumAIOCB. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com From: Beno=C3=AEt 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 cor= ruption. For high availability purpose minority errors are reported via QMP but th= e 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 Signed-off-by: Kevin Wolf --- 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 +=3D qcow2.o qcow2-refcount.o qcow2-cluster.o= qcow2-snapshot.o qcow2-c block-obj-y +=3D qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluste= r.o block-obj-y +=3D qed-check.o block-obj-$(CONFIG_VHDX) +=3D vhdx.o vhdx-endian.o vhdx-log.o +block-obj-y +=3D quorum.o block-obj-y +=3D parallels.o blkdebug.o blkverify.o block-obj-y +=3D snapshot.o qapi.o block-obj-$(CONFIG_WIN32) +=3D 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: + * Beno=C3=AEt 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 la= ter. + * 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 operat= ion it + * performs on its children. + * So for each read/write operation coming from the upper layer there wi= ll 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 rea= d/write + * operation received by the upper layer. + * This structure hold pointers to the QuorumChildRequest structures ins= tances + * 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 AIOC= B */ + + bool is_read; + int vote_ret; +}; --=20 1.8.1.4