[libvirt] [PATCH v3] qemu: Ignore nwfilter binding instantiation issues during reconnect

[John Ferlan]

ping^3?

Tks

John

On 09/06/2018 07:03 PM, John Ferlan wrote:
> 
> ping^2?
> 
> Tks,
> 
> John
> 
> These are essentially what Daniel and I agreed upon during the v2 review
> - link the patches below...
> 
> On 08/30/2018 06:24 PM, John Ferlan wrote:
>> ping?
>>
>> Tks,
>>
>> John
>>
>> On 08/24/2018 10:02 AM, John Ferlan wrote:
>>> https://bugzilla.redhat.com/show_bug.cgi?id=1607202
>>>
>>> It's essentially stated in the nwfilterBindingDelete that we
>>> will allow the admin to shoot themselves in the foot by deleting
>>> the nwfilter binding which then allows them to undefine the
>>> nwfilter that is in use for the running guest...
>>>
>>> However, by allowing this we cause a problem for libvirtd
>>> restart reconnect processing which would then try to recreate
>>> the missing binding attempting to use the deleted filter
>>> resulting in an error and thus shutting the guest down.
>>>
>>> So rather than keep adding virDomainConfNWFilterInstantiate
>>> flags to "ignore" specific error conditions, modify the logic
>>> to ignore, but VIR_WARN errors other than ignoreExists. This
>>> will at least allow the guest to not shutdown for only nwfilter
>>> binding errors that we can now perhaps recover from since we
>>> have the binding create/delete capability.
>>>
>>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>>> ---
>>>
>>>  v2: https://www.redhat.com/archives/libvir-list/2018-August/msg01567.html
>>>
>>>  Differences to v2.  Leave the ignoreExists bool, but just allow and
>>>  VIR_WARN other errors from virDomainConfNWFilterInstantiate. Continue
>>>  processing all filters from error point too.
>>>
>>>  src/qemu/qemu_process.c | 24 ++++++++++++++++--------
>>>  1 file changed, 16 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
>>> index ab749389ee..61a277f468 100644
>>> --- a/src/qemu/qemu_process.c
>>> +++ b/src/qemu/qemu_process.c
>>> @@ -3160,20 +3160,29 @@ qemuProcessNotifyNets(virDomainDefPtr def)
>>>      }
>>>  }
>>>  
>>> -static int
>>> -qemuProcessFiltersInstantiate(virDomainDefPtr def, bool ignoreExists)
>>> +/* Attempt to instantiate the filters. Ignore failures because it's
>>> + * possible that someone deleted a filter binding and the associated
>>> + * filter while the guest was running and we don't want that action
>>> + * to cause failure to keep the guest running during the reconnection
>>> + * processing. Nor do we necessarily want other failures to do the
>>> + * same. We'll just log the error conditions other than of course
>>> + * ignoreExists possibility (e.g. the true flag) */
>>> +static void
>>> +qemuProcessFiltersInstantiate(virDomainDefPtr def)
>>>  {
>>>      size_t i;
>>>  
>>>      for (i = 0; i < def->nnets; i++) {
>>>          virDomainNetDefPtr net = def->nets[i];
>>>          if ((net->filter) && (net->ifname)) {
>>> -            if (virDomainConfNWFilterInstantiate(def->name, def->uuid, net, ignoreExists) < 0)
>>> -                return 1;
>>> +            if (virDomainConfNWFilterInstantiate(def->name, def->uuid, net,
>>> +                                                 true) < 0) {
>>> +                VIR_WARN("filter '%s' instantiation for '%s' failed '%s'",
>>> +                         net->filter, net->ifname, virGetLastErrorMessage());
>>> +                virResetLastError();
>>> +            }
>>>          }
>>>      }
>>> -
>>> -    return 0;
>>>  }
>>>  
>>>  static int
>>> @@ -7892,8 +7901,7 @@ qemuProcessReconnect(void *opaque)
>>>  
>>>      qemuProcessNotifyNets(obj->def);
>>>  
>>> -    if (qemuProcessFiltersInstantiate(obj->def, true))
>>> -        goto error;
>>> +    qemuProcessFiltersInstantiate(obj->def);
>>>  
>>>      if (qemuProcessRefreshDisks(driver, obj, QEMU_ASYNC_JOB_NONE) < 0)
>>>          goto error;
>>>
>>
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