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Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver
From: |
Benoît Canet |
Subject: |
Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver |
Date: |
Tue, 29 Oct 2013 21:06:03 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Le Tuesday 29 Oct 2013 à 18:56:34 (+0100), Max Reitz a écrit :
> Am 29.10.2013 18:55, schrieb Max Reitz:
> > Am 29.10.2013 08:59, schrieb Benoît Canet:
> >> Le Friday 04 Oct 2013 à 16:31:56 (+0200), Max Reitz a écrit :
> >>> On 2013-10-02 14:39, Benoît Canet wrote:
> >>>> It must be applied on top of "block: Add
> >>>> BlockDriver.bdrv_check_ext_snapshot."
> >>>>
> >>>> This patchset create a block driver implementing a quorum using total
> >>>> qemu disk
> >>>> images. Writes are mirrored on the $total files.
> >>>> For the reading part the $total files are read at the same time and a
> >>>> vote is
> >>>> done to determine if a qiov version is present $threshold or more times.
> >>>> It then
> >>>> return this majority version to the upper layers.
> >>>> When i < $threshold versions of the data are returned by the lower layer
> >>>> the
> >>>> quorum is broken and the read return -EIO.
> >>>>
> >>>> The goal of this patchset is to be turned in a QEMU block filter living
> >>>> just
> >>>> above raw-*.c and below qcow2/qed when the required infrastructure will
> >>>> be done.
> >>>>
> >>>> Main use of this feature will be people using NFS appliances which can be
> >>>> subjected to bitflip errors.
> >>>>
> >>>> This patchset can be used to replace blkverify and the out of tree
> >>>> blkmirror.
> >>>>
> >>>> v9: integrate latests comments from kevin
> >>>>
> >>>> Benoît Canet (11):
> >>>> quorum: Create quorum.c, add QuorumSingleAIOCB and QuorumAIOCB.
> >>>> quorum: Create BDRVQuorumState and BlkDriver and do init.
> >>>> quorum: Add quorum_aio_writev and its dependencies.
> >>>> blkverify: Extract qemu_iovec_clone() and qemu_iovec_compare() from
> >>>> blkverify.
> >>>> quorum: Add quorum_aio_readv.
> >>>> quorum: Add quorum mechanism.
> >>>> quorum: Add quorum_getlength().
> >>>> quorum: Add quorum_invalidate_cache().
> >>>> quorum: Add quorum_co_get_block_status.
> >>>> quorum: Add quorum_co_flush().
> >>>> quorum: Add quorum_open() and quorum_close().
> >>>>
> >>>> block/Makefile.objs | 1 +
> >>>> block/blkverify.c | 108 +----
> >>>> block/quorum.c | 1035
> >>>> +++++++++++++++++++++++++++++++++++++++++++++
> >>>> configure | 36 ++
> >>>> include/monitor/monitor.h | 2 +
> >>>> include/qemu-common.h | 2 +
> >>>> monitor.c | 2 +
> >>>> util/iov.c | 103 +++++
> >>>> 8 files changed, 1183 insertions(+), 106 deletions(-)
> >>>> create mode 100644 block/quorum.c
> >>>>
> >>> Could you add a qemu-iotest if possible?
> >> I don't see how to specify quorum to qemu-io for bytes checking.
> >>
> >> Best regards
> >>
> >> Benoît
> > As of commit b543c5cd, you can pass options to the block driver through
> > qemu-io -c open. The problem for quorum is that it cannot handle the
> > filename option (which qemu-io will always set). I've attached a diff to
> > change this behavior (which makes the path parameter for open optional
> > and passes NULL to bdrv_open if it is not given). You're free to make
> > use of it. ;-)
> >
> > If this diff is applied, you can invoke qemu-io with quorum for example
> > as following:
> > qemu-io -c 'open -o
> > file.driver=quorum,file.children.0.file.filename=[Image
> > 1],file.children.1.file.filename=[Image 2],file.vote_threshold=[x]'
> >
> > Max
>
> Obviously forgot to attach the diff.
>
> Max
> diff --git a/qemu-io.c b/qemu-io.c
> index 3b3340a..4d0e9f6 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -57,8 +57,13 @@ static int openfile(char *name, int flags, int growable,
> QDict *opts)
>
> if (growable) {
> if (bdrv_file_open(&qemuio_bs, name, opts, flags, &local_err)) {
> - fprintf(stderr, "%s: can't open device %s: %s\n", progname, name,
> - error_get_pretty(local_err));
> + if (name) {
> + fprintf(stderr, "%s: can't open device %s: %s\n", progname,
> + name, error_get_pretty(local_err));
> + } else {
> + fprintf(stderr, "%s: can't open device: %s\n", progname,
> + error_get_pretty(local_err));
> + }
> error_free(local_err);
> return 1;
> }
> @@ -66,8 +71,13 @@ static int openfile(char *name, int flags, int growable,
> QDict *opts)
> qemuio_bs = bdrv_new("hda");
>
> if (bdrv_open(qemuio_bs, name, opts, flags, NULL, &local_err) < 0) {
> - fprintf(stderr, "%s: can't open device %s: %s\n", progname, name,
> - error_get_pretty(local_err));
> + if (name) {
> + fprintf(stderr, "%s: can't open device %s: %s\n", progname,
> + name, error_get_pretty(local_err));
> + } else {
> + fprintf(stderr, "%s: can't open device: %s\n", progname,
> + error_get_pretty(local_err));
> + }
> error_free(local_err);
> bdrv_unref(qemuio_bs);
> qemuio_bs = NULL;
> @@ -127,6 +137,7 @@ static int open_f(BlockDriverState *bs, int argc, char
> **argv)
> int c;
> QemuOpts *qopts;
> QDict *opts = NULL;
> + char *filename = NULL;
>
> while ((c = getopt(argc, argv, "snrgo:")) != EOF) {
> switch (c) {
> @@ -160,11 +171,13 @@ static int open_f(BlockDriverState *bs, int argc, char
> **argv)
> flags |= BDRV_O_RDWR;
> }
>
> - if (optind != argc - 1) {
> + if (optind == argc - 1) {
> + filename = argv[optind];
> + } else if (optind < argc - 1) {
> return qemuio_command_usage(&open_cmd);
> }
>
> - return openfile(argv[optind], flags, growable, opts);
> + return openfile(filename, flags, growable, opts);
> }
>
> static int quit_f(BlockDriverState *bs, int argc, char **argv)
Thanks a lot.
Best regards
Benoît