Message ID | 1392242799-16364-2-git-send-email-benoit.canet@irqsave.net |
---|---|
State | New |
Headers | show |
On 12.02.2014 23:06, Benoît Canet wrote: > From: Benoît Canet <benoit@irqsave.net> > > 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 reached and -pedantic: "identical", without "s" > 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 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 <benoit@irqsave.net> > Reviewed-by: Max Reitz <mreitz@redhat.com> > --- > 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 <benoit.canet@irqsave.net> > + * > + * 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 > + * $children_count QuorumChildRequest. > + */ > +typedef struct QuorumChildRequest { > + BlockDriverAIOCB *aiocb; > + QEMUIOVector qiov; > + uint8_t *buf; > + int ret; > + QuorumAIOCB *parent; > +} QuorumChildRequest; > + > +/* Quorum will use the following structure to track progress of each read/write > + * operation received by the upper layer. > + * This structure hold pointers to the QuorumChildRequest structures instances > + * used to do operations on each children and track overall progress. > + */ > +struct QuorumAIOCB { > + BlockDriverAIOCB common; > + > + /* Request metadata */ > + uint64_t sector_num; > + int nb_sectors; > + > + QEMUIOVector *qiov; /* calling IOV */ > + > + QuorumChildRequest *qcrs; /* individual child requests */ > + int count; /* number of completed AIOCB */ > + int success_count; /* number of successfully completed AIOCB */ > + > + bool is_read; > + int vote_ret; > +};
diff --git a/block/Makefile.objs b/block/Makefile.objs index e254a21..716556f 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -3,6 +3,7 @@ block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-c block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o block-obj-y += qed-check.o block-obj-$(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 <benoit.canet@irqsave.net> + * + * 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; +};