Re: [Qemu-devel] [PATCH] block: fix streaming/closing race

[Stefan Hajnoczi]

On Fri, Mar 30, 2012 at 9:31 AM, Paolo Bonzini <address@hidden> wrote:
> Il 30/03/2012 09:19, Stefan Hajnoczi ha scritto:
>>> > +void block_job_cancel_sync(BlockJob *job)
>>> > +{
>>> > +    BlockDriverState *bs = job->bs;
>>> > +
>>> > +    assert(bs->job == job);
>>> > +    block_job_cancel(job);
>>> > +    while (bs->job != NULL && bs->job->busy) {
>> It's not clear to me why we have a busy flag.
>
> Because the coroutine does not restart if you do qemu_aio_wait and the
> coroutine is waiting in co_sleep.  So the busy flag communicates that
> the coroutine is quiescent and, when cancelled, will not issue any new I/O.

Ah, yes.  This is tricky, a comment would be nice.

Stefan