LVM : can't create 2 LVs with the same name on 2 differents VGs

Hi,

Using MAAS 2.4.2 (7034-g2f5deb8b8-0ubuntu1)

I have 2 LVM VGs created : vg0 and vg1. When I try to add a logical volume name "lv0" on each (which is perfectly correct), it works fine for the first one, but the second one silently fails, and MAAS logs the following trace. I expect MAAS to accep vg0-lv0 and vg1-lv0 without erroring out.

Thanks !

2018-12-20 10:27:53 maasserver.websockets.protocol: [critical] Error on request (45) machine.create_logical_volume: {"__all__": ["Block device with this Node and Name already exists."]}
        Traceback (most recent call last):
          File "/usr/lib/python3.6/threading.py", line 864, in run
            self._target(*self._args, **self._kwargs)
          File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 850, in worker
            return target()
          File "/usr/lib/python3/dist-packages/twisted/_threads/_threadworker.py", line 46, in work
            task()
          File "/usr/lib/python3/dist-packages/twisted/_threads/_team.py", line 190, in doWork
            task()
        --- <exception caught here> ---
          File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 250, in inContext
            result = inContext.theWork()
          File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 266, in <lambda>
            inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 122, in callWithContext
            return self.currentContext().callWithContext(ctx, func, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 85, in callWithContext
            return func(*args,**kw)
          File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 883, in callInContext
            return func(*args, **kwargs)
          File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 232, in wrapper
            result = func(*args, **kwargs)
          File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 756, in call_within_transaction
            return func_outside_txn(*args, **kwargs)
          File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 563, in retrier
            return func(*args, **kwargs)
          File "/usr/lib/python3.6/contextlib.py", line 52, in inner
            return func(*args, **kwds)
          File "/usr/lib/python3/dist-packages/maasserver/websockets/handlers/machine.py", line 719, in create_logical_volume
            logical_volume = form.save()
          File "/usr/lib/python3/dist-packages/maasserver/forms/__init__.py", line 3778, in save
            size=self.cleaned_data['size'])
          File "/usr/lib/python3/dist-packages/maasserver/models/filesystemgroup.py", line 795, in create_logical_volume
            filesystem_group=self)
          File "/usr/lib/python3/dist-packages/django/db/models/manager.py", line 85, in manager_method
            return getattr(self.get_queryset(), name)(*args, **kwargs)
          File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 394, in create
            obj.save(force_insert=True, using=self.db)
          File "/usr/lib/python3/dist-packages/maasserver/models/virtualblockdevice.py", line 131, in save
            return super(VirtualBlockDevice, self).save(*args, **kwargs)
          File "/usr/lib/python3/dist-packages/maasserver/models/cleansave.py", line 213, in save
            self.validate_unique(exclude=[self._meta.pk.name])
          File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 1041, in validate_unique
            raise ValidationError(errors)
        django.core.exceptions.ValidationError: {'__all__': ['Block device with this Node and Name already exists.']}