[Qemu-devel] [PATCH 00/12] block: bdrv_drained_begin/end for transactions on dataplane devices

[Fam Zheng <famz@redhat.com>]

External I/O requests mustn't come in while we're in the middle of a
QMP transaction. This series adds bdrv_drained_begin and bdrv_drained_end
around "prepare" and "cleanup" in the transaction actions to make sure that.

Note that "backup" action already starts the block job coroutine in prepare,
and "snapshot" action already creates the snapshot, but both are OK because we
call bdrv_drained_begin first.

The nested event loops also dispatch timers and BHs on the same AioContext. The
existing timers are iscsi, curl, qcow2 and qed. The only one that does I/O is
qed, which is dealt with by a new ".bdrv_drain" callback.


Fam Zheng (12):
  aio: Introduce "type" in aio_set_fd_handler and aio_set_event_notifier
  aio: Save fd client type to AioHandler
  nbd: Mark fd handlers client type as "external"
  dataplane: Mark host notifiers' client type as "external"
  aio: introduce aio_{disable,enable}_clients
  block: Introduce "drained begin/end" API
  block: Add "drained begin/end" for transactional external snapshot
  block: Add "drained begin/end" for transactional backup
  block: Add "drained begin/end" for transactional blockdev-backup
  block: Add "drained begin/end" for internal snapshot
  block: Introduce BlockDriver.bdrv_drain callback
  qed: Implement .bdrv_drain

 aio-posix.c                     |  9 +++++--
 aio-win32.c                     |  8 +++++-
 async.c                         | 45 +++++++++++++++++++++++++++++++-
 block.c                         |  2 ++
 block/curl.c                    | 14 +++++-----
 block/io.c                      | 21 +++++++++++++++
 block/iscsi.c                   |  9 +++----
 block/linux-aio.c               |  5 ++--
 block/nbd-client.c              | 10 ++++---
 block/nfs.c                     | 17 +++++-------
 block/qed.c                     |  7 +++++
 block/sheepdog.c                | 38 ++++++++++++++++++---------
 block/ssh.c                     |  5 ++--
 block/win32-aio.c               |  5 ++--
 blockdev.c                      | 27 ++++++++++++++-----
 hw/block/dataplane/virtio-blk.c |  6 +++--
 hw/scsi/virtio-scsi-dataplane.c | 24 +++++++++++------
 include/block/aio.h             | 36 +++++++++++++++++++++++++
 include/block/block.h           | 19 ++++++++++++++
 include/block/block_int.h       |  8 ++++++
 iohandler.c                     |  3 ++-
 nbd.c                           |  4 ++-
 roms/ipxe                       |  2 +-
 tests/test-aio.c                | 58 +++++++++++++++++++++++------------------
 24 files changed, 289 insertions(+), 93 deletions(-)

-- 
2.5.3