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From: Stefan Hajnoczi <stefanha@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH] block: fix streaming/closing race
Date: Fri, 30 Mar 2012 11:25:24 +0100	[thread overview]
Message-ID: <CAJSP0QV52+JJXzBK+01JQOmZcm1n0eRsusUBMeApmBbirM4sYQ@mail.gmail.com> (raw)
In-Reply-To: <4F756F51.5010603@redhat.com>

On Fri, Mar 30, 2012 at 9:31 AM, Paolo Bonzini <pbonzini@redhat.com> 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

  parent reply	other threads:[~2012-03-30 10:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-29 16:08 [Qemu-devel] [PATCH] block: fix streaming/closing race Paolo Bonzini
2012-03-30  7:19 ` Stefan Hajnoczi
2012-03-30  8:31   ` Paolo Bonzini
2012-03-30 10:00     ` Paolo Bonzini
2012-03-30 10:25     ` Stefan Hajnoczi [this message]
2012-03-30 10:29       ` Paolo Bonzini

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