Re: [Qemu-devel] [PATCHv5] rbd block driver fix race between aio completition and aio cancel

[Stefan Priebe - Profihost AG]

fixed in V6

Am 30.11.2012 09:26, schrieb Stefan Hajnoczi:
> On Thu, Nov 29, 2012 at 10:37 PM, Stefan Priebe <address@hidden> 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