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

On Thu, Mar 28, 2019 at 09:53:08AM +0100, Peter Krempa wrote: > On Thu, Mar 28, 2019 at 08:43:46 +0000, Nikolay Shirokovskiy wrote: >> >> >> 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(a)virtuozzo.com&gt; >>>> --- >>>> 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. > > I understand the problem here, but I disagree that the API should return > success if it didn't do anything when it previously was returning > errors. > > You can choose to implement a new error code to be used instead of > VIR_ERR_OPERATION_INVALID in virDomainObjCheckActive. E.g. > VIR_ERR_OBJECT_INACTIVE (to be generic enough to work with > networks/storage pools/etc.) Why can't the mgmt app simply ignore the existing OPERATION_INVALID error they get from destroy.