* cancelled without a call to {@code cancel}, such as by calling {@code
   * setFuture(cancelledFuture)}.
   *
   * <p>Beware of completing a future while holding a lock. Its listeners may do slow work or
   * acquire other locks, risking deadlocks.
   */
  @CanIgnoreReturnValue
  @Override
  public boolean cancel(boolean mayInterruptIfRunning) {
    @RetainedLocalRef Object localValue = value();
    boolean rValue = false;

func (di *distLockInstance) RUnlock(lc LockContext) {
	if lc.cancel != nil {
		lc.cancel()
	}
	di.rwMutex.RUnlock(lc.ctx)
}

// localLockInstance - frontend/top-level interface for namespace locks.
type localLockInstance struct {
	ns     *nsLockMap
	volume string
	paths  []string
	opsID  string
}

// NewNSLock - returns a lock instance for a given volume and

	// works, but only when running one binary at a time.
	// Use a file lock to make sure only one wrapper is running at a time.
	//
	// The lock file is never deleted, to avoid concurrent locks on distinct
	// files with the same path.
	lockName := filepath.Join(os.TempDir(), "go_ios_exec-"+deviceID+".lock")
	lock, err = os.OpenFile(lockName, os.O_CREATE|os.O_RDONLY, 0666)
	if err != nil {
		return 1, err
	}

// name tierName, otherwise returns madmin.Unsupported and false. N B this
// function is meant for internal use, where the caller is expected to take
// appropriate locks.
func (config *TierConfigMgr) isTierNameInUse(tierName string) (madmin.TierType, bool) {
	if t, ok := config.Tiers[tierName]; ok {
		return t.Type, true
	}
	return madmin.Unsupported, false
}

type Manager struct {
	// ID is an instance ID, that will change whenever the server restarts.
	// This allows remotes to keep track of whether state is preserved.
	ID uuid.UUID

	// Immutable after creation, so no locks.
	targets map[string]*Connection

	// serverside handlers.
	handlers handlers

	// local host name.
	local string

	// authToken is a function that will validate a token.
	authToken ValidateTokenFn

import com.google.errorprone.annotations.concurrent.GuardedBy;
import com.google.j2objc.annotations.Weak;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.BooleanSupplier;
import org.jspecify.annotations.Nullable;

/**
 * A synchronization abstraction supporting waiting on arbitrary boolean conditions.
 *

var limit = make(chan int, 3)

func main() {
	for _, w := range work {
		go func(w func()) {
			limit <- 1
			w()
			<-limit
		}(w)
	}
	select{}
}
</pre>

<h3 id="locks">Locks</h3>

<p>
The <code>sync</code> package implements two lock data types,
<code>sync.Mutex</code> and <code>sync.RWMutex</code>.
</p>

<p class="rule">

				Namespace: minioNamespace,
				Subsystem: "locks",
				Name:      "total",
				Help:      "Number of current locks on this peer",
				Type:      gaugeMetric,
			},
			Value: float64(st.Total),
		})
		metrics = append(metrics, MetricV2{
			Description: MetricDescription{
				Namespace: minioNamespace,
				Subsystem: "locks",
				Name:      "write_total",

	PreserveETag                        string    // preserves this etag during a PUT call.
	NoLock                              bool      // indicates to lower layers if the caller is expecting to hold locks.
	HasIfMatch                          bool      // indicates if the request has If-Match header
	ProxyRequest                        bool      // only set for GET/HEAD in active-active replication scenario

			}
			serverLocksResp, err := sys.peerClients[index].GetLocks(ctx)
			if err != nil {
				return err
			}
			locksResp[index] = &PeerLocks{
				Addr:  sys.peerClients[index].host.String(),
				Locks: serverLocksResp,
			}
			return nil
		}, index)
	}
	for index, err := range g.Wait() {
		reqInfo := (&logger.ReqInfo{}).AppendTags("peerAddress",
			sys.peerClients[index].host.String())