var bytesWritten int64
	var bufs [][]byte
	for block := startBlock; block <= endBlock; block++ {
		var blockOffset, blockLength int64
		switch {
		case startBlock == endBlock:
			blockOffset = offset % e.blockSize
			blockLength = length
		case block == startBlock:
			blockOffset = offset % e.blockSize
			blockLength = e.blockSize - blockOffset
		case block == endBlock:
			blockOffset = 0

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"errors"
)

var (
	errLockConflict       = errors.New("lock conflict")
	errLockNotInitialized = errors.New("lock not initialized")
	errLockNotFound       = errors.New("lock not found")

// If block is true, Read and Write will block when there is no data to read or no space to write.
// If block is false, Read and Write will return ErrIsEmpty or ErrIsFull immediately.
// By default, the ring buffer is not blocking.
// This setting should be called before any Read or Write operation or after a Reset.
func (r *RingBuffer) SetBlocking(block bool) *RingBuffer {
	r.block = block
	if block {

	// stop the replay go-routine.
	if h.store != nil {
		h.storeCtxCancel()
	}

	// Set logch to nil and close it.
	// This will block all Send operations,
	// and finish the existing ones.
	// All future ones will be discarded.
	h.logChMu.Lock()
	xioutil.SafeClose(h.logCh)
	h.logCh = nil
	h.logChMu.Unlock()

	if h.producer != nil {
		h.producer.Close()
		h.client.Close()
	}

package cmd

import (
	"context"
	"os"
	"reflect"
	"sync"
	"testing"

	"github.com/minio/minio/internal/dsync"
)

// Helper function to create a lock server for testing
func createLockTestServer(ctx context.Context, t *testing.T) (string, *lockRESTServer, string) {
	obj, fsDir, err := prepareFS(ctx)
	if err != nil {
		t.Fatal(err)
	}

			Source:    t.Name(),
			Owner:     "owner",
			Quorum:    &quorum,
		}
		ok, err := l.RLock(ctx, arg)
		if err != nil {
			t.Fatal(err)
		}
		if !ok {
			t.Fatal("did not get read lock")
		}
		// RLock twice
		ok, err = l.RLock(ctx, arg)
		if err != nil {
			t.Fatal(err)
		}
		if !ok {
			t.Fatal("did not get write lock")
		}

		rResources[i] = arg.Resources[0]
	}

### Locks

We have 3 different things that we synchronize on.

#### Http2Connection

This lock guards internal state of each connection. This lock is never held for blocking operations. That means that we acquire the lock, read or write a few fields and release the lock. No I/O and no application-layer callbacks.

#### Http2Stream

	h.status.Store(statusClosed)
	h.storeCtxCancel()

	// Wait for messages to be sent...
	h.wg.Wait()

	// Set logch to nil and close it.
	// This will block all Send operations,
	// and finish the existing ones.
	// All future ones will be discarded.
	h.logChMu.Lock()
	xioutil.SafeClose(h.logCh)
	h.logCh = nil
	h.logChMu.Unlock()

func (sys *BucketTargetSys) isOffline(ep *url.URL) bool {
	sys.hMutex.RLock()
	defer sys.hMutex.RUnlock()
	if h, ok := sys.hc[ep.Host]; ok {
		return !h.Online
	}
	go sys.initHC(ep)
	return false
}

// markOffline sets endpoint to offline if network i/o timeout seen.
func (sys *BucketTargetSys) markOffline(ep *url.URL) {
	sys.hMutex.Lock()
	defer sys.hMutex.Unlock()
	if h, ok := sys.hc[ep.Host]; ok {

		time.Sleep(time.Duration(d))
	}

	l.mutex.Lock()
	defer l.mutex.Unlock()
	var locksHeld int64
	if locksHeld, reply = l.lockMap[args.Resources[0]]; !reply { // No lock is held on the given name
		return false, fmt.Errorf("RUnlock attempted on an unlocked entity: %s", args.Resources[0])
	}
	if reply = locksHeld != WriteLock; !reply { // A write-lock is held, cannot release a read lock