From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57468) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WETr9-0004D9-Oy for qemu-devel@nongnu.org; Fri, 14 Feb 2014 20:15:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WETqy-0003nG-EE for qemu-devel@nongnu.org; Fri, 14 Feb 2014 20:15:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9905) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WETqy-0003n5-59 for qemu-devel@nongnu.org; Fri, 14 Feb 2014 20:15:36 -0500 Message-ID: <52FEC046.8050401@redhat.com> Date: Sat, 15 Feb 2014 02:17:58 +0100 From: Max Reitz MIME-Version: 1.0 References: <1392242799-16364-1-git-send-email-benoit.canet@irqsave.net> <1392242799-16364-2-git-send-email-benoit.canet@irqsave.net> In-Reply-To: <1392242799-16364-2-git-send-email-benoit.canet@irqsave.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH V17 01/12] quorum: Create quorum.c, add QuorumChildRequest and QuorumAIOCB. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?B?QmVub8OudCBDYW5ldA==?= , qemu-devel@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, =?UTF-8?B?QmVub8OudCBDYW5ldA==?= , stefanha@redhat.com On 12.02.2014 23:06, Beno=C3=AEt Canet wrote: > 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 identicals the quorum is reach= ed and -pedantic: "identical", without "s" > this winning version is returned to the guest. So quorum prevents bit c= orruption. > For high availability purpose minority errors are reported via QMP but = the guest > does not see them. > > This patch create the driver C source file and introduce the structures= that "creates" and "introduces", with "s" But since I'm not in -Werror mode, you may leave the reviewed-by. ;-) Max > 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 +=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-clu= ster.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 = 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 oper= ation 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 r= ead/write > + * operation received by the upper layer. > + * This structure hold pointers to the QuorumChildRequest structures i= nstances > + * 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 AI= OCB */ > + > + bool is_read; > + int vote_ret; > +};