[libvirt] [PATCH] qemu: don't fail on destroy if domain is inactive

[Nikolay Shirokovskiy]

On 28.03.2019 11:27, Peter Krempa wrote:
> On Thu, Mar 28, 2019 at 10:29:01 +0300, Nikolay Shirokovskiy wrote:
>> Mgmt can not track if domain is already inactive before
>> calling destroy because domain can become inactive because
>> of crash/shutdown from guest. Thus it is make sense to
> 
> Well mgmt apps can use events emitted by libvirt precisely for this
> case.

This is still racy.

> 
>> report success in this case. Another option is to return
>> special error code but this is a bit more complicated.
>>
>> Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy at virtuozzo.com>
>> ---
>>  src/qemu/qemu_driver.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>> index 62d8d97..0789efc 100644
>> --- a/src/qemu/qemu_driver.c
>> +++ b/src/qemu/qemu_driver.c
>> @@ -2172,8 +2172,10 @@ qemuDomainDestroyFlags(virDomainPtr dom,
>>      if (virDomainDestroyFlagsEnsureACL(dom->conn, vm->def) < 0)
>>          goto cleanup;
>>  
>> -    if (virDomainObjCheckActive(vm) < 0)
>> +    if (!virDomainObjIsActive(vm)) {
>> +        ret = 0;
>>          goto cleanup;
>> +    }
> 
> I'm not persuaded we want this. The commit message does not provide
> enough means to justify it. Every other API we have returns error in
> case when the domain is in the state the API will change it to so I'm
> not in favor of making this api behave differently.
> 

Ok then here is the usecase. We want to shutdown domain and unfortunately
this operation failed to bring domain to shutoff state in time. Thus mgmt try
to call destroy as it wants domain to be shutoff. Destroy returns quite
general VIR_ERR_OPERATION_INVALID error code so mgmt need to face
the problem but in reality everything is ok.

Nikolay