Re: [Qemu-devel] [PATCH v2 4/7] block: take lock around bdrv_read implementations

[Paolo Bonzini <pbonzini@redhat.com>]

On 11/06/2011 03:27 PM, Avi Kivity wrote:
> On 10/20/2011 01:16 PM, Paolo Bonzini wrote:
>> This does the first part of the conversion to coroutines, by
>> wrapping bdrv_read implementations to take the read side of the
>> rwlock.
>>
>> Drivers that implement bdrv_read rather than bdrv_co_readv can
>> then benefit from asynchronous operation (at least if the underlying
>> protocol supports it, which is not the case for raw-win32), even
>> though they still operate with a bounce buffer.
>>
>> raw-win32 does not need the lock, because it cannot yield.
>> nbd also doesn't probably, but better be safe.
>
> This patch (2914caa088e3fbbd) breaks autotest when a guest reboots after
> install; instead of rebooting, the guest is stuck in the bootloader or
> kernel.

Are any of these formats used by autotest?

  block/bochs.c     |   13 ++++++++++++-
  block/cloop.c     |   13 ++++++++++++-
  block/cow.c       |   13 ++++++++++++-
  block/dmg.c       |   13 ++++++++++++-
  block/nbd.c       |   13 ++++++++++++-
  block/parallels.c |   13 ++++++++++++-
  block/vmdk.c      |   13 ++++++++++++-
  block/vpc.c       |   13 ++++++++++++-
  block/vvfat.c     |   13 ++++++++++++-
  9 files changed, 108 insertions(+), 9 deletions(-)

Perhaps the failure is only reproduced 80-90% of the time and this 
screws up the bisection.

Paolo