type disconnectReader struct {
	r  io.Reader
	mu sync.Mutex
}

func (d *disconnectReader) Read(p []byte) (n int, err error) {
	d.mu.Lock()
	defer d.mu.Unlock()
	if d.r != nil {
		return d.r.Read(p)
	}
	return 0, errors.New("reader closed")
}

func (d *disconnectReader) Close() error {
	d.mu.Lock()
	d.r = nil
	d.mu.Unlock()
	return nil
}

	var incorrectConfigs []error
	var retries int
	var mu sync.Mutex
	for onlineServers < len(clnts)/2 {
		var wg sync.WaitGroup
		wg.Add(len(clnts))
		onlineServers = 0
		for _, clnt := range clnts {
			go func(clnt *bootstrapRESTClient) {
				defer wg.Done()

				if clnt.gridConn.State() != grid.StateConnected {
					mu.Lock()

				//   unformatted or simply not accessible for some reason.
				//
				// - Do not consume disks which are being healed
				//
				// - Future: skip busy disks
				return
			}

			mu.Lock()
			newDisks = append(newDisks, disks[i])
			mu.Unlock()
		}()
	}
	wg.Wait()
	return newDisks
}

func (er erasureObjects) getOnlineLocalDisks() (newDisks []StorageAPI) {
	disks := er.getOnlineDisks()

}

func (d *naughtyDisk) Close() (err error) {
	if err = d.calcError(); err != nil {
		return err
	}
	return d.disk.Close()
}

func (d *naughtyDisk) calcError() (err error) {
	d.mu.Lock()
	defer d.mu.Unlock()
	d.callNR++
	if err, ok := d.errors[d.callNR]; ok {
		return err
	}
	if d.defaultErr != nil {
		return d.defaultErr
	}
	return nil
}

				go func() {
					defer wg.Done()
					for info := range updates {
						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
					}

			old := e.cached.Swap(newAcc)
			var a AccElem
			a.Size = atomic.LoadInt64(&old.Size)
			a.Total = atomic.LoadInt64(&old.Total)
			a.N = atomic.LoadInt64(&old.N)
			e.mu.Lock()
			e.lastMinuteLatency.addAll(t-1, a)
			e.mu.Unlock()
			acc = newAcc
		} else {
			// We may be able to grab the new accumulator by yielding.
			runtime.Gosched()
			acc = e.cached.Load()
		}
	}

	const isWriteLock = false
	return lm.lockLoop(ctx, id, source, timeout, isWriteLock)
}

func (lm *LRWMutex) lock(id, source string, isWriteLock bool) (locked bool) {
	lm.mu.Lock()
	defer lm.mu.Unlock()

	lm.id = id
	lm.source = source
	if isWriteLock {
		if lm.ref == 0 && !lm.isWriteLock {
			lm.ref = 1
			lm.isWriteLock = true
			locked = true
		}
	} else {
		if !lm.isWriteLock {

	// Return a transient bucket for invalid or system buckets.
	m.mu.RLock()
	b, ok := m.buckets[bucket]
	if ok {
		m.mu.RUnlock()
		if b.bucket != bucket {
			logger.Info("getBucket: cached bucket %s does not match this bucket %s", b.bucket, bucket)
			debug.PrintStack()
		}
		return b
	}

	m.mu.RUnlock()
	m.mu.Lock()
	defer m.mu.Unlock()
	// See if someone else fetched it while we waited for the lock.

			go func(i int, set *erasureObjects) {
				defer wg.Done()
				err := set.listPath(listCtx, o, innerResults)
				mu.Lock()
				defer mu.Unlock()
				if err == nil {
					allAtEOF = false
				}
				errs[i] = err
			}(len(errs), set)
			errs = append(errs, nil)
		}
	}
	mu.Unlock()

	// Gather results to a single channel.
	// Quorum is one since we are merging across sets.

	type PaddedMutex struct {
		*DRWMutex
	}
	b.RunParallel(func(pb *testing.PB) {
		mu := PaddedMutex{NewDRWMutex(ds, "")}
		for pb.Next() {
			mu.Lock(id, source)
			mu.Unlock(context.Background())
		}
	})
}

func benchmarkMutex(b *testing.B, slack, work bool) {
	b.ResetTimer()
	b.ReportAllocs()

	mu := NewDRWMutex(ds, "")
	if slack {
		b.SetParallelism(10)
	}