}

func (config *TierConfigMgr) refreshedAt() time.Time {
	config.RLock()
	defer config.RUnlock()
	return config.lastRefreshedAt
}

// IsTierValid returns true if there exists a remote tier by name tierName,
// otherwise returns false.
func (config *TierConfigMgr) IsTierValid(tierName string) bool {
	config.RLock()
	defer config.RUnlock()
	_, valid := config.isTierNameInUse(tierName)
	return valid
}

	for _, rule := range lc.Rules {
		if rule.Transition.StorageClass != "" {
			if valid := globalTierConfigMgr.IsTierValid(rule.Transition.StorageClass); !valid {
				return errInvalidStorageClass
			}
		}
		if rule.NoncurrentVersionTransition.StorageClass != "" {
			if valid := globalTierConfigMgr.IsTierValid(rule.NoncurrentVersionTransition.StorageClass); !valid {
				return errInvalidStorageClass
			}
		}
	}