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

	}
}

// Lock holds a write lock on dm.
//
// If the lock is already in use, the calling go routine
// blocks until the mutex is available.
func (dm *DRWMutex) Lock(id, source string) {
	isReadLock := false
	dm.lockBlocking(context.Background(), nil, id, source, isReadLock, Options{
		Timeout: drwMutexInfinite,
	})
}

// Options lock options.
type Options struct {

}

// List - returns available target IDs.
func (list *TargetList) List() []TargetID {
	list.RLock()
	defer list.RUnlock()

	keys := []TargetID{}
	for k := range list.targets {
		keys = append(keys, k)
	}

	return keys
}

func (list *TargetList) get(id TargetID) (Target, bool) {
	list.RLock()
	defer list.RUnlock()

	target, ok := list.targets[id]
	return target, ok
}

// Metadata has data stripped, if any.
func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) (err error) {
	legacyFS := !(s.fsType == xfs || s.fsType == ext4)

	s.RLock()
	legacy := s.formatLegacy
	s.RUnlock()

	// Verify if volume is valid and it exists.
	volumeDir, err := s.getVolDir(opts.Bucket)
	if err != nil {
		return err
	}

	if !skipAccessChecks(opts.Bucket) {

	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 (p *podNetnsCache) Get(uid string) Netns {
	// lock current snapshot pod map
	p.mu.RLock()
	defer p.mu.RUnlock()
	if info, f := p.currentPodCache[uid]; f {
		return info.Netns
	}
	return nil
}

// make sure uid is in the cache, even if we don't have a netns
func (p *podNetnsCache) Ensure(uid string) {
	p.mu.Lock()
	defer p.mu.Unlock()
	if _, ok := p.currentPodCache[uid]; !ok {

		}
		m.addResponse(Response{Err: ErrIncorrectSequence})
		return false
	}
	m.RecvSeq++
	return true
}

// response will send handleIncoming response to client.
// may never block.
// Should return whether the next call would block.
func (m *muxClient) response(seq uint32, r Response) {
	if debugReqs {
		fmt.Println(m.MuxID, m.parent.String(), "RESP")
	}
	if debugPrint {

func (r *ReqInfo) GetTags() []KeyVal {
	if r == nil {
		return nil
	}
	r.RLock()
	defer r.RUnlock()
	return append(make([]KeyVal, 0, len(r.tags)), r.tags...)
}

// GetTagsMap - returns the user defined tags in a map structure
func (r *ReqInfo) GetTagsMap() map[string]interface{} {
	if r == nil {
		return nil
	}
	r.RLock()
	defer r.RUnlock()
	m := make(map[string]interface{}, len(r.tags))

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 {

	}

	// Compare only necessary headers
	compareKeys := []string{
		"Expires",
		"Cache-Control",
		"Content-Language",
		"Content-Disposition",
		"X-Amz-Object-Lock-Mode",
		"X-Amz-Object-Lock-Retain-Until-Date",
		"X-Amz-Object-Lock-Legal-Hold",
		"X-Amz-Website-Redirect-Location",
		"X-Amz-Meta-",
	}

	// compare metadata on both maps to see if meta is identical
	compareMeta1 := make(map[string]string)