'Extends a volume if required
In case src_vref size is smaller than the size if the requested
new volume call _resize().'

def _extend_if_required(self, volume, src_vref):

    if (volume.size != src_vref.size):
        LOG.debug("resize    volume    '%(dst_vol)s'    from    %(src_size)d    to    %(dst_size)d", {'dst_vol': volume.name, 'src_size': src_vref.size, 'dst_size': volume.size})
        self._resize(volume)
