private Synchronized() {}

  private static class SynchronizedObject implements Serializable {
    final Object delegate;
    final Object mutex;

    SynchronizedObject(Object delegate, @Nullable Object mutex) {
      this.delegate = checkNotNull(delegate);
      this.mutex = (mutex == null) ? this : mutex;
    }

    Object delegate() {
      return delegate;
    }

    // No equals and hashCode; see ForwardingObject for details.

  private Synchronized() {}

  private static class SynchronizedObject implements Serializable {
    final Object delegate;
    final Object mutex;

    SynchronizedObject(Object delegate, @Nullable Object mutex) {
      this.delegate = checkNotNull(delegate);
      this.mutex = (mutex == null) ? this : mutex;
    }

    Object delegate() {
      return delegate;
    }

    // No equals and hashCode; see ForwardingObject for details.

	nrRequests   uint64
	major, minor uint32
	fsType       string

	immediatePurge       chan string
	immediatePurgeCancel context.CancelFunc

	// mutex to prevent concurrent read operations overloading walks.
	rotational bool
	walkMu     *sync.Mutex
	walkReadMu *sync.Mutex
}

// checkPathLength - returns error if given path name length more than 255
func checkPathLength(pathName string) error {

// BatchJobPool batch job pool
type BatchJobPool struct {
	ctx          context.Context
	objLayer     ObjectLayer
	once         sync.Once
	mu           sync.Mutex
	jobCh        chan *BatchJobRequest
	jmu          sync.Mutex // protects jobCancelers
	jobCancelers map[string]context.CancelFunc
	workerKillCh chan struct{}
	workerSize   int
}

var globalBatchJobPool *BatchJobPool

)

// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet.
var (
	randN  uint32
	randmu sync.Mutex
)

// Temp files created in default Tmp dir
var globalTestTmpDir = os.TempDir()

// reseed - returns a new seed every time the function is called.
func reseed() uint32 {

	// metrics
	LastRefreshTimeUnixNano         uint64
	LastRefreshDurationMilliseconds uint64
	TotalRefreshSuccesses           uint64
	TotalRefreshFailures            uint64

	sync.Mutex

	iamRefreshInterval time.Duration

	LDAPConfig   xldap.Config  // only valid if usersSysType is LDAPUsers
	OpenIDConfig openid.Config // only valid if OpenID is configured

		ReadData:         readData,
		InclFreeVersions: opts.InclFreeVersions,
		Healing:          false,
	}

	mrfCheck := make(chan FileInfo)
	defer xioutil.SafeClose(mrfCheck)

	var rw sync.Mutex

	// Ask for all disks first;
	go func() {
		ctx, cancel := context.WithCancel(ctx)
		defer cancel()

		wg := sync.WaitGroup{}
		for i, disk := range disks {
			if disk == nil {
				done <- false

	// Updates must be closed before we return.
	defer xioutil.SafeClose(updates)

	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	var wg sync.WaitGroup
	var mu sync.Mutex
	var results []dataUsageCache
	var firstErr error

	allBuckets, err := z.ListBuckets(ctx, BucketOptions{})
	if err != nil {
		return err
	}

	if len(allBuckets) == 0 {

		return policies, nil
	}

	if userPolicyPresent {
		// if user mapping present and no group policies found
		// rely on user policy for access, instead of fallback.
		return nil, nil
	}

	var mu sync.Mutex

	// no mappings found, fallback for all groups.
	g := errgroup.WithNErrs(len(groups)).WithConcurrency(10) // load like 10 groups at a time.

	for index := range groups {
		g.Go(func() error {