Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver

[Max Reitz]

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

qemu-io-open.diff
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