'Get information of volume\'s backing.
If the volume does not have a backing yet. It will be created.
:param volume: Volume object
:param connector: Connector information
:return: Return connection information'

def _initialize_connection(self, volume, connector):

    backing = self.volumeops.get_backing(volume.name)
    if ('instance' in connector):
        instance = vim_util.get_moref(connector['instance'], 'VirtualMachine')
        LOG.debug('The    instance:    %s    for    which    initialize    connection    is    called,    exists.', instance)
        host = self.volumeops.get_host(instance)
        if (not backing):
            LOG.info('There    is    no    backing    for    the    volume:    %s.    Need    to    create    one.', volume.name)
            backing = self._create_backing(volume, host)
        else:
            self._relocate_backing(volume, backing, host)
    else:
        LOG.debug('The    instance    for    which    initialize    connection    is    called,    does    not    exist.')
        if (not backing):
            LOG.warning('Trying    to    boot    from    an    empty    volume:    %s.', volume.name)
            backing = self._create_backing(volume)
    return self._get_connection_info(volume, backing, connector)
