'get pool capacity.'

@lockutils.synchronized('ETERNUS-update', 'cinder-', True)
def update_volume_stats(self):

    self.conn = self._get_eternus_connection()
    eternus_pool = self._get_drvcfg('EternusPool')
    LOG.debug('update_volume_stats,    pool    name:    %s.', eternus_pool)
    pool = self._find_pool(eternus_pool, True)
    if pool:
        self.stats['total_capacity_gb'] = (pool['TotalManagedSpace'] / units.Gi)
        self.stats['free_capacity_gb'] = (pool['RemainingManagedSpace'] / units.Gi)
    else:
        LOG.warning('update_volume_stats,    eternus_pool:%(eternus_pool)s,    specified    pool    is    not    found.', {'eternus_pool': eternus_pool})
        self.stats['total_capacity_gb'] = 0
        self.stats['free_capacity_gb'] = 0
    self.stats['multiattach'] = False
    LOG.debug('update_volume_stats,    eternus_pool:%(eternus_pool)s,    total    capacity[%(total)s],    free    capacity[%(free)s].', {'eternus_pool': eternus_pool, 'total': self.stats['total_capacity_gb'], 'free': self.stats['free_capacity_gb']})
    return (self.stats, eternus_pool)
