'Save volume metadata to container.
This will fetch all fields from the db VolumeMetadata object for
volume_id and save them in the provided container dictionary.'

def _save_vol_meta(self, container, volume_id):

    type_tag = self.TYPE_TAG_VOL_META
    LOG.debug("Getting    metadata    type    '%s'", type_tag)
    meta = self.db.volume_metadata_get(self.context, volume_id)
    if meta:
        container[type_tag] = {}
        for entry in meta:
            if (not self._is_serializable(meta[entry])):
                LOG.info("Unable    to    serialize    field    '%s'    -    excluding    from    backup", entry)
                continue
            container[type_tag][entry] = meta[entry]
        LOG.debug("Completed    fetching    metadata    type    '%s'", type_tag)
    else:
        LOG.debug("No    metadata    type    '%s'    available", type_tag)
