<p class="rule">
For any call to <code>l.RLock</code> on a <code>sync.RWMutex</code> variable <code>l</code>,
there is an <i>n</i> such that the <i>n</i>th call to <code>l.Unlock</code>
is synchronized before the return from <code>l.RLock</code>,
and the matching call to <code>l.RUnlock</code> is synchronized before the return from call <i>n</i>+1 to <code>l.Lock</code>.
</p>

<p class="rule">

Klaus Post <******@****.***> 1759093161 +0200

	lock := z.serverPools[0].NewNSLock(minioMetaBucket, rebalMetaName)
	lkCtx, err := lock.GetLock(ctx, globalOperationTimeout)
	if err != nil {
		rebalanceLogIf(ctx, fmt.Errorf("failed to acquire write lock on %s/%s: %w", minioMetaBucket, rebalMetaName, err))
		return err
	}
	defer lock.Unlock(lkCtx)

	ctx = lkCtx.Context()

		}
	}

	return &LockedFile{File: f}, nil
}

// TryLockedOpenFile - tries a new write lock, functionality
// it is similar to LockedOpenFile with with syscall.LOCK_EX
// mode but along with syscall.LOCK_NB such that the function
// doesn't wait forever but instead returns if it cannot
// acquire a write lock.
func TryLockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {

Klaus Post <******@****.***> 1759093161 +0200

		srs.Failed.addsize(st.TransferSize, st.Err)
	case st.Pending:
	}
	sr.M[dID] = srs
}

func (sr *SRStats) get() map[string]SRMetric {
	epMap := globalBucketTargetSys.healthStats()

	sr.lock.RLock()
	defer sr.lock.RUnlock()
	m := make(map[string]SRMetric, len(sr.M))
	for dID, v := range sr.M {
		t := newXferStats()
		mx := make(map[RMetricName]XferStats)

		if v.XferRateLrg != nil {

// - '> 0' interval duration between cycles
func (opts Config) BitrotScanCycle() (d time.Duration) {
	configMutex.RLock()
	defer configMutex.RUnlock()
	return opts.cache.bitrotCycle
}

// Clone safely the heal configuration
func (opts Config) Clone() (int, time.Duration, string) {
	configMutex.RLock()
	defer configMutex.RUnlock()
	return opts.IOCount, opts.Sleep, opts.Bitrot
}

func (pr *syncReadCloser) Read(p []byte) (n int, err error) {
	// This ensures that Close will block until Read has completed.
	// This allows another goroutine to close the reader.
	pr.mu.Lock()
	defer pr.mu.Unlock()
	if pr.rc == nil {
		return 0, io.EOF
	}
	return pr.rc.Read(p)
}

func (pr *syncReadCloser) Close() error {
	pr.mu.Lock()
	defer pr.mu.Unlock()
	if pr.rc != nil {
		err := pr.rc.Close()
		pr.rc = nil

	// https://issuetracker.google.com/issues/73230216.
	lockPath := filepath.Join(os.TempDir(), "go_android_exec-adb-lock")
	lock, err := os.OpenFile(lockPath, os.O_CREATE|os.O_RDWR, 0666)
	if err != nil {
		return 0, err
	}
	defer lock.Close()
	if err := syscall.Flock(int(lock.Fd()), syscall.LOCK_EX); err != nil {
		return 0, err
	}

	// In case we're booting a device or emulator alongside all.bash, wait for

	if o.Bucket != b.bucket {
		logger.Info("bucketMetacache.findCache: bucket %s does not match this bucket %s", o.Bucket, b.bucket)
		debug.PrintStack()
		return metacache{}
	}

	// Grab a write lock, since we create one if we cannot find one.
	b.mu.Lock()
	defer b.mu.Unlock()

	// Check if exists already.
	if c, ok := b.caches[o.ID]; ok {
		c.lastHandout = time.Now()
		b.caches[o.ID] = c
		b.debugf("returning existing %v", o.ID)