'Extend an existing volume.
:param volume: volume reference
:param new_size: volume new size in GB'

def extend_volume(self, volume, new_size):

    LOG.info('Extending    volume:    %(id)s    New    size:    %(size)s    GB', {'id': volume['id'], 'size': new_size})
    self.nms.zvol.set_child_prop(self._get_zvol_name(volume['name']), 'volsize', ('%sG' % new_size))
