// concurrently reading and writing the IAM storage. The (r)lock()
	// functions return the iamCache. The cache can be safely written to
	// only when returned by `lock()`.
	lock() *iamCache
	unlock()
	rlock() *iamCache
	runlock()
	getUsersSysType() UsersSysType
	loadPolicyDoc(ctx context.Context, policy string, m map[string]PolicyDoc) error

		binary.LittleEndian.PutUint16(data[2:4], version)

		buf, err := ri.MarshalMsg(data)
		ri.mu.Unlock()
		if err != nil {
			return err
		}
		path, err := ri.getJobReportPath()
		if err != nil {
			batchLogIf(ctx, err)
			return err
		}
		return saveConfig(ctx, api, path, buf)
	}
	ri.mu.Unlock()
	return nil
}

// Note: to be used only with batch jobs that affect multiple versions through

func (s *xlStorage) GetDiskID() (string, error) {
	s.RLock()
	diskID := s.diskID
	fileInfo := s.formatFileInfo
	lastCheck := s.formatLastCheck

	// check if we have a valid disk ID that is less than 1 seconds old.
	if fileInfo != nil && diskID != "" && time.Since(lastCheck) <= 1*time.Second {
		s.RUnlock()
		return diskID, nil
	}
	s.RUnlock()

	fi, err := s.checkFormatJSON()
	if err != nil {

						mu.Lock()
						results[i] = info
						mu.Unlock()
					}
				}()
				// Start scanner. Blocks until done.
				err := erObj.nsScanner(ctx, allBuckets, wantCycle, updates, healScanMode)
				if err != nil {
					scannerLogIf(ctx, err)
					mu.Lock()
					if firstErr == nil {
						firstErr = err
					}
					// Cancel remaining...
					cancel()
					mu.Unlock()
					return
				}

func (sys *IAMSys) Init(ctx context.Context, objAPI ObjectLayer, etcdClient *etcd.Client, iamRefreshInterval time.Duration) {
	bootstrapTraceMsg("IAM initialization started")
	globalServerConfigMu.RLock()
	s := globalServerConfig
	globalServerConfigMu.RUnlock()

	openidConfig, err := openid.LookupConfig(s,
		NewHTTPTransport(), xhttp.DrainBody, globalSite.Region())
	if err != nil {

		// - xl.meta metadata is still verified for quorum under lock()
		//   however writing the response doesn't need to serialize
		//   concurrent writers
		unlockOnDefer = true
		nsUnlocker = func() { lock.RUnlock(lkctx) }
	}

	fi, metaArr, onlineDisks, err := er.getObjectFileInfo(ctx, bucket, object, opts, true)
	if err != nil {
		return nil, toObjectErr(err, bucket, object)
	}

		return
	}
}

var errUnsupportedSignal = fmt.Errorf("unsupported signal")

func waitingDrivesNode() map[string]madmin.DiskMetrics {
	globalLocalDrivesMu.RLock()
	localDrives := cloneDrives(globalLocalDrivesMap)
	globalLocalDrivesMu.RUnlock()

	errs := make([]error, len(localDrives))
	infos := make([]DiskInfo, len(localDrives))
	for i, drive := range localDrives {

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          maybeDrainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    @GuardedBy("this")
    void drainKeyReferenceQueue(ReferenceQueue<K> keyReferenceQueue) {
      Reference<? extends K> ref;
      int i = 0;

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          maybeDrainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    @GuardedBy("this")
    void drainKeyReferenceQueue(ReferenceQueue<K> keyReferenceQueue) {
      Reference<? extends K> ref;
      int i = 0;

	globalObjLayerMutex.Lock()
	globalObjectAPI = nil
	globalObjLayerMutex.Unlock()
}

// reset the value of the Global server config.
// set it to `nil`.
func resetGlobalConfig() {
	// hold the mutex lock before a new config is assigned.
	globalServerConfigMu.Lock()
	// Save the loaded config globally.
	globalServerConfig = nil
	globalServerConfigMu.Unlock()
}

func resetGlobalEndpoints() {