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

[Cole Robinson]

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