[Qemu-devel] [PATCH 0/3] block: fix and detect qemu_aio_wait() issues

[Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>]

This series fixes an issue where qemu_aio_flush() would return to IDE hardware
emulation with requests still pending.  Kevin Wolf <kwolf@redhat.com> found it
in the block tree before qemu.git/master merge, so qemu.git/master is not
affected and these patches are against his tree.

A recent interaction between copy-on-read and "qcow2: Unlock during COW"
emphasized the need for strong assertion checking.  Patch 1 fixes an assertion
failure with qcow2 images in hw/ide/pci.c:bmdma_cmd_writeb().

Patches 2 and 3 then introduce assertions that detect
wait_for_overlapping_requests() deadlock and broken qemu_aio_wait().  In the
future we will have better information if issues related to qemu_aio_wait()
come up.

I have run qemu-iotests for qcow2 and qed.  I have also performed a RHEL6 guest
install to qed and tested booting the guest with IDE and qcow2.

Stefan Hajnoczi (3):
  qcow2: avoid reentrant bdrv_read() in copy_sectors()
  block: wait_for_overlapping_requests() deadlock detection
  block: convert qemu_aio_flush() calls to bdrv_drain_all()

 block-migration.c     |    2 +-
 block.c               |   27 +++++++++++++++++++++++++++
 block.h               |    1 +
 block/qcow2-cluster.c |   27 +++++++++++++++++++--------
 blockdev.c            |    4 ++--
 cpus.c                |    2 +-
 hw/ide/macio.c        |    5 +++--
 hw/ide/pci.c          |    2 +-
 hw/virtio-blk.c       |    2 +-
 hw/xen_platform.c     |    2 +-
 qemu-io.c             |    4 ++--
 savevm.c              |    2 +-
 xen-mapcache.c        |    2 +-
 13 files changed, 61 insertions(+), 21 deletions(-)

-- 
1.7.7.3