type IAMStorageAPI interface {
	// The role of the read-write lock is to prevent go routines from
	// 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

	if ri == nil {
		return
	}

	ri.mu.Lock()
	defer ri.mu.Unlock()

	ri.Bucket = bucket
	ri.Object = info.Name
	ri.countItem(info.Size, info.DeleteMarker, success)
}

func (ri *batchJobInfo) trackCurrentBucketBatch(bucket string, batch []ObjectInfo) {
	if ri == nil {
		return
	}

	ri.mu.Lock()
	defer ri.mu.Unlock()

	ri.Bucket = bucket
	for i := range batch {

}

// sets globalObjectAPI to `nil`.
func resetGlobalObjectAPI() {
	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

	defer func() {
		if unlockOnDefer {
			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := z.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()
		nsUnlocker = func() { lock.RUnlock(lkctx) }
		unlockOnDefer = true
	}

	checkPrecondFn := opts.CheckPrecondFn

		return nil, errCorruptedBackend
	}
	return fi, nil
}

// GetDiskID - returns the cached disk uuid
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.

   * of reads may not be immediately reflected on the algorithm's data structures. These structures
   * are guarded by a lock and operations are applied in batches to avoid lock contention. The
   * penalty of applying the batches is spread across threads so that the amortized cost is slightly
   * higher than performing just the operation without enforcing the capacity constraint.

			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := er.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()

		// Release lock when the metadata is verified, and reader
		// is ready to be read.
		//
		// This is possible to be lock free because

   * then:
   *
   * <ul>
   *   <li>{@code isDone()} must return {@code true}
   *   <li>{@code isCancelled()} must return {@code false}
   *   <li>{@code get()} must not block, and it must throw an {@code ExecutionException} with the
   *       return value of this method as its cause
   * </ul>
   *
   * <p>This method is {@code protected} so that classes like {@code

		s.writeErrorResponse(w, err)
		return
	}
}

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

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

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

		UserAgent:    r.UserAgent(),
		Host:         handlers.GetSourceIP(r),
	})
}

// PutBucketObjectLockConfigHandler - PUT Bucket object lock configuration.
// ----------
// Places an Object Lock configuration on the specified bucket. The rule
// specified in the Object Lock configuration will be applied by default
// to every new object placed in the specified bucket.