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

["Benoît Canet" <benoit@irqsave.net>]

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

-- 
1.8.1.2