[libvirt] [PATCH] qemu: call endjob in RevertToSnapshot

[Jincheng Miao]

On 08/28/2014 10:09 AM, Jincheng Miao wrote:
>
> On 08/27/2014 07:52 PM, Eric Blake wrote:
>> On 08/27/2014 03:20 AM, Jincheng Miao wrote:
>>> On 08/27/2014 11:02 AM, Eric Blake wrote:
>>>> On 08/26/2014 08:10 PM, Jincheng Miao wrote:
>>>>> In qemuDomainRevertToSnapshot(), it will check snap->def->state.
>>>>> But when the state is PMSUSPENDED/NOSTATE/BLOCKED, it forgets to
>>>>> call qemuDomainObjEndJob.
>>>>>
>>>>> Signed-off-by: Jincheng Miao <jmiao at redhat.com>
>>>>> ---
>>>>>    src/qemu/qemu_driver.c |    4 ++--
>>>>>    1 files changed, 2 insertions(+), 2 deletions(-)
>>>> This looks like the fix for
>>>> https://bugzilla.redhat.com/show_bug.cgi?id=1134154 - thanks for 
>>>> chasing
>>>> that!
>>> This patch fix the part of that bug, but it doesn't touch the race
>>> condition:
>>> Why the snap->def->state is NOSTATE? It should be RUNNING.
>>> The only reasonable explanation is that snapshot object is free()ed.
>>>
>>> IMHO, the SnapshotObjList should be clocked during snapshot job 
>>> running.
>> Okay, I see what you are saying; we need to make sure two parallel
>> snapshot operations can't stomp on one another (probably by making them
>> all guarded by the vm job lock).
>
> Yes, wrapper the snapshot operations by vm job lock good choice,

s/good choice/is a good choice/

> and I will check some other functions, and compose a patch for it.
>
>
>> I hope to have time to look into a fix
>> before 1.2.8; but as it has been a long-standing issue, it's not a new
>> regression in this release if I miss that goal (my priority today is
>> getting 1.2.8 APIs to be feature-complete).
>>
>
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