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
