From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Subject: Re: [PATCHv5] rbd block driver fix race between aio completition
 and aio cancel
Date: Fri, 30 Nov 2012 09:57:53 +0100
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, Josh Durgin <josh.durgin@inktank.com>, ceph-devel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>

fixed in V6

Am 30.11.2012 09:26, schrieb Stefan Hajnoczi:
> On Thu, Nov 29, 2012 at 10:37 PM, Stefan Priebe <s.priebe@profihost.ag> wrote:
>> @@ -568,6 +562,10 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb)
>>   {
>>       RBDAIOCB *acb = (RBDAIOCB *) blockacb;
>>       acb->cancelled = 1;
>> +
>> +    while (acb->status == -EINPROGRESS) {
>> +        qemu_aio_wait();
>> +    }
>>   }
>>
>>   static const AIOCBInfo rbd_aiocb_info = {
>> @@ -639,6 +637,7 @@ static void rbd_aio_bh_cb(void *opaque)
>>       acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
>>       qemu_bh_delete(acb->bh);
>>       acb->bh = NULL;
>> +    acb->status = 0;
>>
>>       qemu_aio_release(acb);
>>   }
>
> We cannot release acb in rbd_aio_bh_cb() when acb->cancelled == 1
> because qemu_rbd_aio_cancel() still accesses it.  This was discussed
> in an early version of the patch.
>
> Stefan
>