[libvirt] [PATCH] qemu: fix state change lock held byremoteDispatchDomainBlockJobAbort forever

[Xiubo Li]

...
>> +++++++++++++++++++++++++++++++++++++++++
>> 2016-08-26 07:51:05.685+0000: 8916: warning : qemuDomainObjBeginJobInternal:1571 :
>> Cannot start job (query, none) for domain instance-00001b3a; current job is (modify,
>> none) owned by (8914 remoteDispatchDomainBlockJobAbort, 0 <null>) for (30s, 0s)
>>
>> 2016-08-26 07:51:05.685+0000: 8916: error : qemuDomainObjBeginJobInternal:1583 :
>> Timed out during operation: cannot acquire state change lock (held by
>> remoteDispatchDomainBlockJobAbort)
>> -----------------------------------------
>>

...
>
> However, the patch is wrong. We should just never attempt to wait for
> the event if we already got it. In other words, diskPriv->blockjob
> should have already be false at this point.
>
> Jirka
>

Yes, right. I missed the qemuBlockJobUpdate() before the while().

I am not sure, whether there has other reason to cause the "event" reply 
missed by libvirtd ? or just ignored/lost by the qemu ?

These months, we have encountered 3 times about the case when the error 
and warning logs occured, the VM will have no responding forever, only 
through reboot it.

Thanks very much.

BRs
Xiubo