'Connects the disk image to the Virtual Machine.
:param instance: nova instance to which to attach the disk.
:param disk_info: The pypowervm storage element returned from
create_disk_from_image.  Ex. VOptMedia, VDisk, LU,
or PV.
:param stg_ftsk: FeedTask to defer storage connectivity operations.'

def attach_disk(self, instance, disk_info, stg_ftsk):

    lu = pvm_stg.LU.bld_ref(self._adapter, disk_info.name, disk_info.udid)
    lpar_uuid = vm.get_pvm_uuid(instance)
    def add_func(vios_w):
        LOG.info('Attaching    SSP    disk    from    VIOS    %s.', vios_w.name, instance=instance)
        mapping = tsk_map.build_vscsi_mapping(self._host_uuid, vios_w, lpar_uuid, lu)
        return tsk_map.add_map(vios_w, mapping)
    for vios_uuid in self._vios_uuids:
        stg_ftsk.wrapper_tasks[vios_uuid].add_functor_subtask(add_func)
