Re: [Qemu-devel] [Qemu-stable] 2.1 unexpected stop after exporting blockdev via nbd server

[Stefan Hajnoczi]

On Thu, Jan 8, 2015 at 1:17 AM, Michael Roth <address@hidden> wrote:
> Quoting Stefan Hajnoczi (2015-01-06 05:49:11)
>> On Mon, Jan 05, 2015 at 05:12:10PM +0400, Andrey Korolyov wrote:
>> > On Fri, Jan 2, 2015 at 4:04 PM, Stefan Hajnoczi <address@hidden> wrote:
>> > > On Thu, Dec 18, 2014 at 07:38:59PM +0400, Andrey Korolyov wrote:
>> > >> 2.1-stable is currently crashing with the
>> > >>
>> > >> Co-routine re-entered recursively
>> > >> 2014-12-16 15:06:23.578+0000: shutting down
>> > >>
>> > >> after execution of (for example) following when using virtio-dp as a
>> > >> disk backend:
>> > >>
>> > >> '{ "execute": "nbd-server-start", "arguments": { "addr": { "type":
>> > >> "inet", "data": { "host": "10.6.0.1", "port": "3333" } } } }'
>> > >> '{ "execute": "nbd-server-add", "arguments": {"device":
>> > >> "drive-virtio-disk0","writable": false } }'
>> > >
>> > > Hi,
>> > > You need patches from Max Reitz that make the run-time NBD server
>> > > support dataplane:
>> > > f214928 nbd: Follow the BDS' AIO context
>> > > 3338442 block: Add AIO context notifiers
>> > > 958c717 nbd: Drop nbd_can_read()
>> > >
>> > > Please try QEMU v2.2.0 or qemu.git.
>> > >
>> > > Stefan
>> >
>> > Thanks Stefan, those commits are enough to make dataplane drive work
>> > well with runtime nbd server. By the way, can such functionality
>> > improvements (not major improvements like discard support for scsi)
>> > make their way as backports? To reword this, unexpected behavior like
>> > sudden shutdown I described is better to be closed by later fixes than
>> > by stubs or left as it currently behaving IMO.
>>
>> Oops, I typoed the address@hidden email address.  Trying
>> again...
>>
>> QEMU stable folks: will there be another 2.1.x release?
>
> Yes, 2.1.3 was very poorly timed to go out before Christmas but obviously
> that didn't happen. The patch round-up should go out tomorrow with the
> freeze next Wednesday. The updated schedule is available here:
>
> http://qemu-project.org/Planning/2.1#Release_Schedule

Excellent, please add the following commits to stable:
f214928 nbd: Follow the BDS' AIO context
3338442 block: Add AIO context notifiers
958c717 nbd: Drop nbd_can_read()

They prevent crashes when the run-time NBD server is used together
with virtio-blk dataplane.

They apply cleanly onto stable-2.1 and I have tested that the crash is solved.

Thanks,
Stefan