[pve-devel] [PATCH qemu-server 1/2] Fix #1441: Do not unplug controllers when the mirroring is finished

[Fabian Grünbichler]

On Thu, Aug 24, 2017 at 07:05:35AM +0200, Thomas Lamprecht wrote:
> On 08/23/2017 07:15 PM, Alexandre DERUMIER wrote:
> > for me, this patch is ok.
> > 
> > if the job is complete, we don't need to unplug. (and that mean that vm need to support unplug too, we can't be sure that guest support this).
> > 
> > Is it possible that the problem was the previous bug with unix socket, were the target vm was not paused after migration ?
> > 
> 
> Could be possible.
> 
> Looking at the qemu-server and qemu source Emmanuel's patch seems, in fact, valid.
> 
> All mirror block jobs are finished at this point, we do a "nbd-server-stop" on,
> the target which disconnects all NBD clients, as everything from the source side
> using NBD is mirrored, flushed and happy this should not run into a problem there.
> 
> Same for qemu's do_vm_stop, which drains and flushes all remaining blockjobs (which
> there shouldn't be any a this point, else we would have mirrored/migrated an unclean
> state?!)
> 
> I'd still wait for Wolfgang B.'s opinion on this, he knows far more on the topic.

I originally added the device_del because I experienced long delays in
stopping the source VM, but I did not debug further (and unfortunately
cannot remember more details). if such delays are not reproducible
(anymore) when taking out that foreach, I am OK with it.

I think my tests were with -rc5, so it is possible something changed on
the Qemu side as well..