[libvirt] [PATCH] qemu: Only restore security label when saving is successfull.

[Osier Yang]

于 2011年03月29日 03:07, Eric Blake 写道:
> On 03/27/2011 10:16 PM, Osier Yang wrote:
>> 于 2011年03月25日 23:54, Eric Blake 写道:
>>> On 03/25/2011 02:54 AM, Osier Yang wrote:
>>>> "qemudDomainSaveFlag" trys to restore security label even if
>>>> the saving fails, a useless warning will be thowed then, e.g.
>>>> if "doStopVcpus" fails.
>>>>
>>>> * src/qemu/qemu_driver.c
>>>> ---
>
>>>>        virCgroupPtr cgroup = NULL;
>>>> +    bool saved = false;
>>>
>>> You don't need this if we can key off of some other condition.
>>>
>>>>
>
>> No, that's not the original patch meant, and this attached patch
>> doesn't fix the problem.
>>
>>      /* Pause */
>>      if (vm->state == VIR_DOMAIN_RUNNING) {
>>          header.was_running = 1;
>>          if (qemuProcessStopCPUs(driver, vm)<  0)
>>              goto endjob;
>>
>> The original patch meant:
>>
>> In case of "qemuProcessStopCPUs" failure, (in RHEL, it's
>> "doStopVcpus"), which means VM is still not NULL, and
>> "bypassSecurityDriver" is never changed before, (it's initialized
>> as 0 at the beginning), so, when it jumps to "endjob", it
>> must try to restore the label for the saving path, however,
>> it even didn't try to save (even no label setting before), as
>> a result, it will always warn "No such file or directory, bla bla".
>>
>> So changing "bypassSecurityDriver" after the first restoring
>> attempt doesn't work.
>
> Aha - I see what you mean.  We had _two_ logic bugs, and I only fixed
> the second one (we restored the label twice on a late error), whereas
> you were trying to fix the first (we restore the label even if we never
> set it in the first place on an early error).
>
> Meanwhile, my fd: migration already touched this file, so your patch no
> longer applies.  I think I fixed that incidentally by moving the
> labeling into qemu_migration.c (that is, commit 6034ddd55 should fix the
> issue you were first testing).  Now, the bypassSecurityDriver in
> qemu_driver.c doesn't affect any cleanup paths early or late, and in the
> new qemuMigrationToFile, bypassSecurityDriver is coupled with the new
> restoreLabel boolean which is set only when the labeling took place, so
> the cleanup is properly gated.
>

I looked through commit 6034ddd55, it should fix the problem,
thanks for picking it up incidentally.

Osier