Comment 1 for bug 1856767

Since I had to try to get back the capability to make incremental backups, I tried a few things.
In /usr/lib/python2.7/dist-packages/cinder/backup/drivers/ceph.py, I changed the code for the function
_get_backup_base_name to:
    def _get_backup_base_name(self, volume_id, backup=None):
        # Ensure no unicode
        if backup.service_metadata:
            return self._format_base_name(backup.service_metadata)
        else:
            return utils.convert_str("volume-%s.backup.base" % volume_id)

I know this is a REALLY dirty fix, but at least I'm able to backup my volumes, both in Full backup mode and in incremental mode.