Re: [Qemu-devel] [Qemu-block] [PATCH v2 10/16] mirror: Do initial aio context move of target via BB interface

[Fam Zheng <famz@redhat.com>]

On Thu, 05/11 16:27, Stefan Hajnoczi wrote:
> On Wed, Apr 19, 2017 at 05:43:50PM +0800, Fam Zheng wrote:
> > diff --git a/blockdev.c b/blockdev.c
> > index dfd1385..53f9874 100644
> > --- a/blockdev.c
> > +++ b/blockdev.c
> > @@ -3556,8 +3556,6 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
> >          goto out;
> >      }
> >  
> > -    bdrv_set_aio_context(target_bs, aio_context);
> > -
> >      blockdev_mirror_common(arg->has_job_id ? arg->job_id : NULL, bs, target_bs,
> >                             arg->has_replaces, arg->replaces, arg->sync,
> >                             backing_mode, arg->has_speed, arg->speed,
> > @@ -3608,8 +3606,6 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id,
> >      aio_context = bdrv_get_aio_context(bs);
> >      aio_context_acquire(aio_context);
> >  
> > -    bdrv_set_aio_context(target_bs, aio_context);
> > -
> >      blockdev_mirror_common(has_job_id ? job_id : NULL, bs, target_bs,
> >                             has_replaces, replaces, sync, backing_mode,
> >                             has_speed, speed,
> 
> This patch post-pones bdrv_set_aio_context() until later on.  We now
> call bdrv_get_info() without holding target_bs's AioContext in
> mirror_start_job().
> 
> Please acquire the AioContext around target_bs accesses until we move it
> to our AioContext.

Good catch! Will fix.

Fam