[libvirt] xend_internal: Use domain/status for shutdown check

[Cole Robinson]

On 04/10/2012 09:32 AM, Stefan Bader wrote:
> On 10.04.2012 15:22, Cole Robinson wrote:
>> On 04/10/2012 04:46 AM, Stefan Bader wrote:
>>> On 04/08/2012 03:08 PM, Cole Robinson wrote:
>>>> On 04/02/2012 10:38 AM, Stefan Bader wrote:
>>>>> xend_internal: Use domain/status for shutdown check
>>>>>
>>>>> On newer xend (v3.x and after) there is no state and domid reported
>>>>> for inactive domains. When initially creating connections this is
>>>>> handled in various places by assigning domain->id = -1.
>>>>> But once an instance has been running, the id is set to the current
>>>>> domain id. And it does not change when the instance is shut down.
>>>>> So when querying the domain info, the hypervisor driver, which gets
>>>>> asked first will indicate it cannot find information, then the
>>>>> xend driver is asked and will set the status to NOSTATE because it
>>>>> checks for the -1 domain id.
>>>>> Checking domain/status for 0 seems to be more reliable for that.
>>>>>
>>>>> One note: I am not sure whether the domain->id also should get set
>>>>> back to -1 whenever any sub-driver thinks the instance is no longer
>>>>> running.
>>>>>
>>>>> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=746007
>>>>> BugLink: http://bugs.launchpad.net/bugs/929626
>>>>>
>>>>> Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
>>>>>
>>>>> Index: libvirt-0.9.8/src/xen/xend_internal.c
>>>>> ===================================================================
>>>>> --- libvirt-0.9.8.orig/src/xen/xend_internal.c	2011-12-04 08:15:00.000000000 +0100
>>>>> +++ libvirt-0.9.8/src/xen/xend_internal.c	2012-03-23 11:07:43.575529377 +0100
>>>>> @@ -989,9 +989,11 @@
>>>>>              state = VIR_DOMAIN_BLOCKED;
>>>>>          else if (strchr(flags, 'r'))
>>>>>              state = VIR_DOMAIN_RUNNING;
>>>>> -    } else if (domain->id < 0) {
>>>>> -        /* Inactive domains don't have a state reported, so
>>>>> -           mark them SHUTOFF, rather than NOSTATE */
>>>>> +    } else if (sexpr_int(root, "domain/status") == 0) {
>>>>
>>>> Maybe this should be
>>>>
>>>> (domain->id < 0 || sexpr_int(root, ...
>>>>
>>> It would not matter. Since the status is zero for all non-running domains it
>>> covers those with domain->id < 0 as well.
>>>
>>
>> Even for RHEL5 vintage xen? Since we historically try to maintain
>> compatibility with that. It may well work, but unless it's tested I don't
>> think there's much harm in keeping the id < 0 check to preserve old behavior.
>>
>> Thanks,
>> Cole
> 
> I checked against CentOS5.5 (close enough). But right, it should not harm to
> have it. I re-submit the patch as soon as I have recovered my failed attempt to
> recover a raid failure... :/
> 

If you checked against a centos5 host, I'm fine with that. So ACK to this patch.

- Cole