func TestMirrorEndpointLookup(t *testing.T) {
	containsMirror := func(endpoints []APIEndpoint) bool {
		for _, pe := range endpoints {
			if pe.URL.Host == "my.mirror" {
				return true
			}
		}
		return false
	}
	s := DefaultService{config: makeServiceConfig([]string{"my.mirror"}, nil)}

	imageName, err := reference.WithName(IndexName + "/test/image")
	if err != nil {
		t.Error(err)
	}
	pushAPIEndpoints, err := s.LookupPushEndpoints(imageName.Hostname())
	if err != nil {
		t.Fatal(err)
	}
	if containsMirror(pushAPIEndpoints) {
		t.Fatal("Push endpoint should not contain mirror")
	}

	pullAPIEndpoints, err := s.LookupPullEndpoints(imageName.Hostname())
	if err != nil {
		t.Fatal(err)
	}
	if !containsMirror(pullAPIEndpoints) {
		t.Fatal("Pull endpoint should contain mirror")
	}
}

// Add adds an image to the image cache
func (ic *ICache) Add(imageConfig *metadata.ImageConfig) {
	defer trace.End(trace.Begin(""))

	ic.m.Lock()
	defer ic.m.Unlock()

	// Normalize the name stored in imageConfig using Docker's reference code
	ref, err := reference.WithName(imageConfig.Name)
	if err != nil {
		log.Errorf("Tried to create reference from %s: %s", imageConfig.Name, err.Error())
		return
	}

	imageID := prefixImageID(imageConfig.ImageID)
	ic.iDIndex.Add(imageConfig.ImageID)
	ic.cacheByID[imageID] = imageConfig

	for _, tag := range imageConfig.Tags {
		ref, err = reference.WithTag(ref, tag)
		if err != nil {
			log.Errorf("Tried to create tagged reference from %s and tag %s: %s", imageConfig.Name, tag, err.Error())
			return
		}
		ic.cacheByName[imageConfig.Reference] = imageConfig
	}
}

func (l *tarexporter) legacyLoad(tmpDir string, outStream io.Writer, progressOutput progress.Output) error {
	legacyLoadedMap := make(map[string]image.ID)

	dirs, err := ioutil.ReadDir(tmpDir)
	if err != nil {
		return err
	}

	// every dir represents an image
	for _, d := range dirs {
		if d.IsDir() {
			if err := l.legacyLoadImage(d.Name(), tmpDir, legacyLoadedMap, progressOutput); err != nil {
				return err
			}
		}
	}

	// load tags from repositories file
	repositoriesPath, err := safePath(tmpDir, legacyRepositoriesFileName)
	if err != nil {
		return err
	}
	repositoriesFile, err := os.Open(repositoriesPath)
	if err != nil {
		if !os.IsNotExist(err) {
			return err
		}
		return repositoriesFile.Close()
	}
	defer repositoriesFile.Close()

	repositories := make(map[string]map[string]string)
	if err := json.NewDecoder(repositoriesFile).Decode(&repositories); err != nil {
		return err
	}

	for name, tagMap := range repositories {
		for tag, oldID := range tagMap {
			imgID, ok := legacyLoadedMap[oldID]
			if !ok {
				return fmt.Errorf("invalid target ID: %v", oldID)
			}
			named, err := reference.WithName(name)
			if err != nil {
				return err
			}
			ref, err := reference.WithTag(named, tag)
			if err != nil {
				return err
			}
			l.setLoadedTag(ref, imgID, outStream)
		}
	}

	return nil
}

// TagImage creates the tag specified by newTag, pointing to the image named
// imageName (alternatively, imageName can also be an image ID).
func (daemon *Daemon) TagImage(imageName, repository, tag string) error {
	imageID, err := daemon.GetImageID(imageName)
	if err != nil {
		return err
	}

	newTag, err := reference.WithName(repository)
	if err != nil {
		return err
	}
	if tag != "" {
		if newTag, err = reference.WithTag(newTag, tag); err != nil {
			return err
		}
	}

	return daemon.TagImageWithReference(imageID, newTag)
}

// AddImage adds an image to the image cache
func (ic *ICache) AddImage(imageConfig *metadata.ImageConfig) {

	ic.m.Lock()
	defer ic.m.Unlock()

	var imageID string

	// Don't assume the image id in image has "sha256:<id> as format.  We store it in
	// this fomat to make it easier to lookup by digest
	if strings.HasPrefix(imageConfig.ImageID, "sha") {
		imageID = imageConfig.ImageID
	} else {
		imageID = "sha256:" + imageConfig.ImageID
	}

	// add image id to truncindex
	ic.idIndex.Add(imageConfig.ImageID)

	ic.cacheByID[imageID] = imageConfig

	// Normalize the name stored in imageConfig using Docker's reference code
	ref, err := reference.WithName(imageConfig.Name)
	if err != nil {
		log.Errorf("Tried to create reference from %s: %s", imageConfig.Name, err.Error())
		return
	}

	for _, tag := range imageConfig.Tags {
		ref, err = reference.WithTag(ref, tag)
		if err != nil {
			log.Errorf("Tried to create tagged reference from %s and tag %s: %s", imageConfig.Name, tag, err.Error())
			return
		}

		if tagged, ok := ref.(reference.NamedTagged); ok {
			taggedName := fmt.Sprintf("%s:%s", tagged.Name(), tagged.Tag())
			ic.cacheByName[taggedName] = imageConfig
		} else {
			ic.cacheByName[ref.Name()] = imageConfig
		}
	}
}

func handlerPutTag(w http.ResponseWriter, r *http.Request) {
	if !requiresAuth(w, r) {
		return
	}
	vars := mux.Vars(r)
	repositoryName, err := reference.WithName(vars["repository"])
	if err != nil {
		apiError(w, "Could not parse repository", 400)
		return
	}
	tagName := vars["tag"]
	tags, exists := testRepositories[repositoryName.String()]
	if !exists {
		tags = make(map[string]string)
		testRepositories[repositoryName.String()] = tags
	}
	tagValue := ""
	readJSON(r, tagValue)
	tags[tagName] = tagValue
	writeResponse(w, true, 200)
}

func handlerGetDeleteTags(w http.ResponseWriter, r *http.Request) {
	if !requiresAuth(w, r) {
		return
	}
	repositoryName, err := reference.WithName(mux.Vars(r)["repository"])
	if err != nil {
		apiError(w, "Could not parse repository", 400)
		return
	}
	tags, exists := testRepositories[repositoryName.String()]
	if !exists {
		apiError(w, "Repository not found", 404)
		return
	}
	if r.Method == "DELETE" {
		delete(testRepositories, repositoryName.String())
		writeResponse(w, true, 200)
		return
	}
	writeResponse(w, tags, 200)
}

func (s *router) postImagesTag(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if err := httputils.ParseForm(r); err != nil {
		return err
	}
	repo := r.Form.Get("repo")
	tag := r.Form.Get("tag")
	newTag, err := reference.WithName(repo)
	if err != nil {
		return err
	}
	if tag != "" {
		if newTag, err = reference.WithTag(newTag, tag); err != nil {
			return err
		}
	}
	if err := s.daemon.TagImage(newTag, vars["name"]); err != nil {
		return err
	}
	w.WriteHeader(http.StatusCreated)
	return nil
}

func handlerGetTag(w http.ResponseWriter, r *http.Request) {
	if !requiresAuth(w, r) {
		return
	}
	vars := mux.Vars(r)
	repositoryName, err := reference.WithName(vars["repository"])
	if err != nil {
		apiError(w, "Could not parse repository", 400)
		return
	}
	tagName := vars["tag"]
	tags, exists := testRepositories[repositoryName.String()]
	if !exists {
		apiError(w, "Repository not found", 404)
		return
	}
	tag, exists := tags[tagName]
	if !exists {
		apiError(w, "Tag not found", 404)
		return
	}
	writeResponse(w, tag, 200)
}

// parseRemoteRef parses the remote reference into a reference.Named
// returning the tag associated with the reference. In the case the
// given reference string includes both digest and tag, the returned
// reference will have the digest without the tag, but the tag will
// be returned.
func parseRemoteRef(remote string) (reference.Named, string, error) {
	// Parse remote reference, supporting remotes with name and tag
	// NOTE: Using distribution reference to handle references
	// containing both a name and digest
	remoteRef, err := distreference.ParseNamed(remote)
	if err != nil {
		return nil, "", err
	}

	var tag string
	if t, ok := remoteRef.(distreference.Tagged); ok {
		tag = t.Tag()
	}

	// Convert distribution reference to docker reference
	// TODO: remove when docker reference changes reconciled upstream
	ref, err := reference.WithName(remoteRef.Name())
	if err != nil {
		return nil, "", err
	}
	if d, ok := remoteRef.(distreference.Digested); ok {
		ref, err = reference.WithDigest(ref, d.Digest())
		if err != nil {
			return nil, "", err
		}
	} else if tag != "" {
		ref, err = reference.WithTag(ref, tag)
		if err != nil {
			return nil, "", err
		}
	} else {
		ref = reference.WithDefaultTag(ref)
	}

	return ref, tag, nil
}

//.........这里部分代码省略.........
	rwTar, err := daemon.exportContainerRw(container)
	if err != nil {
		return "", err
	}
	defer func() {
		if rwTar != nil {
			rwTar.Close()
		}
	}()

	var history []image.History
	rootFS := image.NewRootFS()
	osVersion := ""
	var osFeatures []string

	if container.ImageID != "" {
		img, err := daemon.imageStore.Get(container.ImageID)
		if err != nil {
			return "", err
		}
		history = img.History
		rootFS = img.RootFS
		osVersion = img.OSVersion
		osFeatures = img.OSFeatures
	}

	l, err := daemon.layerStore.Register(rwTar, rootFS.ChainID())
	if err != nil {
		return "", err
	}
	defer layer.ReleaseAndLog(daemon.layerStore, l)

	h := image.History{
		Author:     c.Author,
		Created:    time.Now().UTC(),
		CreatedBy:  strings.Join(container.Config.Cmd, " "),
		Comment:    c.Comment,
		EmptyLayer: true,
	}

	if diffID := l.DiffID(); layer.DigestSHA256EmptyTar != diffID {
		h.EmptyLayer = false
		rootFS.Append(diffID)
	}

	history = append(history, h)

	config, err := json.Marshal(&image.Image{
		V1Image: image.V1Image{
			DockerVersion:   dockerversion.Version,
			Config:          newConfig,
			Architecture:    runtime.GOARCH,
			OS:              runtime.GOOS,
			Container:       container.ID,
			ContainerConfig: *container.Config,
			Author:          c.Author,
			Created:         h.Created,
		},
		RootFS:     rootFS,
		History:    history,
		OSFeatures: osFeatures,
		OSVersion:  osVersion,
	})

	if err != nil {
		return "", err
	}

	id, err := daemon.imageStore.Create(config)
	if err != nil {
		return "", err
	}

	if container.ImageID != "" {
		if err := daemon.imageStore.SetParent(id, container.ImageID); err != nil {
			return "", err
		}
	}

	if c.Repo != "" {
		newTag, err := reference.WithName(c.Repo) // todo: should move this to API layer
		if err != nil {
			return "", err
		}
		if c.Tag != "" {
			if newTag, err = reference.WithTag(newTag, c.Tag); err != nil {
				return "", err
			}
		}
		if err := daemon.TagImageWithReference(id, newTag); err != nil {
			return "", err
		}
	}

	attributes := map[string]string{
		"comment": c.Comment,
	}
	daemon.LogContainerEventWithAttributes(container, "commit", attributes)
	return id.String(), nil
}

func (pd *v2PushDescriptor) Upload(ctx context.Context, progressOutput progress.Output) (distribution.Descriptor, error) {
	if fs, ok := pd.layer.(distribution.Describable); ok {
		if d := fs.Descriptor(); len(d.URLs) > 0 {
			progress.Update(progressOutput, pd.ID(), "Skipped foreign layer")
			return d, nil
		}
	}

	diffID := pd.DiffID()

	pd.pushState.Lock()
	if descriptor, ok := pd.pushState.remoteLayers[diffID]; ok {
		// it is already known that the push is not needed and
		// therefore doing a stat is unnecessary
		pd.pushState.Unlock()
		progress.Update(progressOutput, pd.ID(), "Layer already exists")
		return descriptor, nil
	}
	pd.pushState.Unlock()

	// Do we have any metadata associated with this layer's DiffID?
	v2Metadata, err := pd.v2MetadataService.GetMetadata(diffID)
	if err == nil {
		descriptor, exists, err := layerAlreadyExists(ctx, v2Metadata, pd.repoInfo, pd.repo, pd.pushState)
		if err != nil {
			progress.Update(progressOutput, pd.ID(), "Image push failed")
			return distribution.Descriptor{}, retryOnError(err)
		}
		if exists {
			progress.Update(progressOutput, pd.ID(), "Layer already exists")
			pd.pushState.Lock()
			pd.pushState.remoteLayers[diffID] = descriptor
			pd.pushState.Unlock()
			return descriptor, nil
		}
	}

	logrus.Debugf("Pushing layer: %s", diffID)

	// if digest was empty or not saved, or if blob does not exist on the remote repository,
	// then push the blob.
	bs := pd.repo.Blobs(ctx)

	var layerUpload distribution.BlobWriter
	mountAttemptsRemaining := 3

	// Attempt to find another repository in the same registry to mount the layer
	// from to avoid an unnecessary upload.
	// Note: metadata is stored from oldest to newest, so we iterate through this
	// slice in reverse to maximize our chances of the blob still existing in the
	// remote repository.
	for i := len(v2Metadata) - 1; i >= 0 && mountAttemptsRemaining > 0; i-- {
		mountFrom := v2Metadata[i]

		sourceRepo, err := reference.ParseNamed(mountFrom.SourceRepository)
		if err != nil {
			continue
		}
		if pd.repoInfo.Hostname() != sourceRepo.Hostname() {
			// don't mount blobs from another registry
			continue
		}

		namedRef, err := reference.WithName(mountFrom.SourceRepository)
		if err != nil {
			continue
		}

		// TODO (brianbland): We need to construct a reference where the Name is
		// only the full remote name, so clean this up when distribution has a
		// richer reference package
		remoteRef, err := distreference.WithName(namedRef.RemoteName())
		if err != nil {
			continue
		}

		canonicalRef, err := distreference.WithDigest(remoteRef, mountFrom.Digest)
		if err != nil {
			continue
		}

		logrus.Debugf("attempting to mount layer %s (%s) from %s", diffID, mountFrom.Digest, sourceRepo.FullName())

		layerUpload, err = bs.Create(ctx, client.WithMountFrom(canonicalRef))
		switch err := err.(type) {
		case distribution.ErrBlobMounted:
			progress.Updatef(progressOutput, pd.ID(), "Mounted from %s", err.From.Name())

			err.Descriptor.MediaType = schema2.MediaTypeLayer

			pd.pushState.Lock()
			pd.pushState.confirmedV2 = true
			pd.pushState.remoteLayers[diffID] = err.Descriptor
			pd.pushState.Unlock()

			// Cache mapping from this layer's DiffID to the blobsum
			if err := pd.v2MetadataService.Add(diffID, metadata.V2Metadata{Digest: mountFrom.Digest, SourceRepository: pd.repoInfo.FullName()}); err != nil {
				return distribution.Descriptor{}, xfer.DoNotRetry{Err: err}
			}
			return err.Descriptor, nil
//.........这里部分代码省略.........

func (pd *v2PushDescriptor) Upload(ctx context.Context, progressOutput progress.Output) (distribution.Descriptor, error) {
	if fs, ok := pd.layer.(distribution.Describable); ok {
		if d := fs.Descriptor(); len(d.URLs) > 0 {
			progress.Update(progressOutput, pd.ID(), "Skipped foreign layer")
			return d, nil
		}
	}

	diffID := pd.DiffID()

	pd.pushState.Lock()
	if descriptor, ok := pd.pushState.remoteLayers[diffID]; ok {
		// it is already known that the push is not needed and
		// therefore doing a stat is unnecessary
		pd.pushState.Unlock()
		progress.Update(progressOutput, pd.ID(), "Layer already exists")
		return descriptor, nil
	}
	pd.pushState.Unlock()

	maxMountAttempts, maxExistenceChecks, checkOtherRepositories := getMaxMountAndExistenceCheckAttempts(pd.layer)

	// Do we have any metadata associated with this layer's DiffID?
	v2Metadata, err := pd.v2MetadataService.GetMetadata(diffID)
	if err == nil {
		// check for blob existence in the target repository if we have a mapping with it
		descriptor, exists, err := pd.layerAlreadyExists(ctx, progressOutput, diffID, false, 1, v2Metadata)
		if exists || err != nil {
			return descriptor, err
		}
	}

	// if digest was empty or not saved, or if blob does not exist on the remote repository,
	// then push the blob.
	bs := pd.repo.Blobs(ctx)

	var layerUpload distribution.BlobWriter

	// Attempt to find another repository in the same registry to mount the layer from to avoid an unnecessary upload
	candidates := getRepositoryMountCandidates(pd.repoInfo, pd.hmacKey, maxMountAttempts, v2Metadata)
	for _, mountCandidate := range candidates {
		logrus.Debugf("attempting to mount layer %s (%s) from %s", diffID, mountCandidate.Digest, mountCandidate.SourceRepository)
		createOpts := []distribution.BlobCreateOption{}

		if len(mountCandidate.SourceRepository) > 0 {
			namedRef, err := reference.WithName(mountCandidate.SourceRepository)
			if err != nil {
				logrus.Errorf("failed to parse source repository reference %v: %v", namedRef.String(), err)
				pd.v2MetadataService.Remove(mountCandidate)
				continue
			}

			// TODO (brianbland): We need to construct a reference where the Name is
			// only the full remote name, so clean this up when distribution has a
			// richer reference package
			remoteRef, err := distreference.WithName(namedRef.RemoteName())
			if err != nil {
				logrus.Errorf("failed to make remote reference out of %q: %v", namedRef.RemoteName(), namedRef.RemoteName())
				continue
			}

			canonicalRef, err := distreference.WithDigest(distreference.TrimNamed(remoteRef), mountCandidate.Digest)
			if err != nil {
				logrus.Errorf("failed to make canonical reference: %v", err)
				continue
			}

			createOpts = append(createOpts, client.WithMountFrom(canonicalRef))
		}

		// send the layer
		lu, err := bs.Create(ctx, createOpts...)
		switch err := err.(type) {
		case nil:
			// noop
		case distribution.ErrBlobMounted:
			progress.Updatef(progressOutput, pd.ID(), "Mounted from %s", err.From.Name())

			err.Descriptor.MediaType = schema2.MediaTypeLayer

			pd.pushState.Lock()
			pd.pushState.confirmedV2 = true
			pd.pushState.remoteLayers[diffID] = err.Descriptor
			pd.pushState.Unlock()

			// Cache mapping from this layer's DiffID to the blobsum
			if err := pd.v2MetadataService.TagAndAdd(diffID, pd.hmacKey, metadata.V2Metadata{
				Digest:           err.Descriptor.Digest,
				SourceRepository: pd.repoInfo.FullName(),
			}); err != nil {
				return distribution.Descriptor{}, xfer.DoNotRetry{Err: err}
			}
			return err.Descriptor, nil
		default:
			logrus.Infof("failed to mount layer %s (%s) from %s: %v", diffID, mountCandidate.Digest, mountCandidate.SourceRepository, err)
		}

		if len(mountCandidate.SourceRepository) > 0 &&
			(metadata.CheckV2MetadataHMAC(&mountCandidate, pd.hmacKey) ||
				len(mountCandidate.HMAC) == 0) {
//.........这里部分代码省略.........

// Update adds new images to the cache
func (c *ImageCache) Update(client *client.PortLayer) error {
	c.m.Lock()
	defer c.m.Unlock()

	CacheNotUpdated = true

	log.Debugf("Updating image cache...")

	host, err := guest.UUID()
	if host == "" {
		host, err = os.Hostname()
	}
	if err != nil {
		return fmt.Errorf("Unexpected error getting hostname: %s", err)
	}

	// attempt to create the image store if it doesn't exist
	store := &models.ImageStore{Name: host}
	_, err = client.Storage.CreateImageStore(
		storage.NewCreateImageStoreParams().WithBody(store),
	)

	if err != nil {
		if _, ok := err.(*storage.CreateImageStoreConflict); ok {
			log.Debugf("Store already exists")
		} else {
			log.Debugf("Creating a store failed: %#v", err)
			return err
		}
	}

	params := storage.NewListImagesParams().WithStoreName(host)

	layers, err := client.Storage.ListImages(params)
	if err != nil {
		return fmt.Errorf("Failed to retrieve image list from portlayer: %s", err)
	}

	for _, layer := range layers.Payload {
		imageConfig := &metadata.ImageConfig{}
		if err := json.Unmarshal([]byte(layer.Metadata["metaData"]), imageConfig); err != nil {
			derr.NewErrorWithStatusCode(fmt.Errorf("Failed to unmarshal image config: %s", err),
				http.StatusInternalServerError)
		}

		if imageConfig.ImageID != "" {
			var imageID string

			// Don't assume the image id in image has "sha256:<id> as format.  We store it in
			// this fomat to make it easier to lookup by digest
			if strings.HasPrefix(imageConfig.ImageID, "sha") {
				imageID = imageConfig.ImageID
			} else {
				imageID = "sha256:" + imageConfig.ImageID
			}

			c.cacheByID[imageID] = imageConfig

			// Normalize the name stored in imageConfig using Docker's reference code
			ref, err := reference.WithName(imageConfig.Name)
			if err != nil {
				log.Errorf("Tried to create reference from %s: %s", imageConfig.Name, err.Error())
				continue
			}

			for id := range imageConfig.Tags {
				tag := imageConfig.Tags[id]
				ref, err = reference.WithTag(ref, tag)
				if err != nil {
					log.Errorf("Tried to create tagged reference from %s and tag %s: %s", imageConfig.Name, tag, err.Error())
					continue
				}

				if tagged, ok := ref.(reference.NamedTagged); ok {
					taggedName := fmt.Sprintf("%s:%s", tagged.Name(), tagged.Tag())
					c.cacheByName[taggedName] = imageConfig
				} else {
					c.cacheByName[ref.Name()] = imageConfig
				}
			}
		}
	}

	CacheNotUpdated = false
	return nil
}

func (pd *v2PushDescriptor) Upload(ctx context.Context, progressOutput progress.Output) error {
	diffID := pd.DiffID()

	pd.pushState.Lock()
	if _, ok := pd.pushState.remoteLayers[diffID]; ok {
		// it is already known that the push is not needed and
		// therefore doing a stat is unnecessary
		pd.pushState.Unlock()
		progress.Update(progressOutput, pd.ID(), "Layer already exists")
		return nil
	}
	pd.pushState.Unlock()

	// Do we have any metadata associated with this layer's DiffID?
	v2Metadata, err := pd.v2MetadataService.GetMetadata(diffID)
	if err == nil {
		descriptor, exists, err := layerAlreadyExists(ctx, v2Metadata, pd.repoInfo, pd.repo, pd.pushState)
		if err != nil {
			progress.Update(progressOutput, pd.ID(), "Image push failed")
			return retryOnError(err)
		}
		if exists {
			progress.Update(progressOutput, pd.ID(), "Layer already exists")
			pd.pushState.Lock()
			pd.pushState.remoteLayers[diffID] = descriptor
			pd.pushState.Unlock()
			return nil
		}
	}

	logrus.Debugf("Pushing layer: %s", diffID)

	// if digest was empty or not saved, or if blob does not exist on the remote repository,
	// then push the blob.
	bs := pd.repo.Blobs(ctx)

	var mountFrom metadata.V2Metadata

	// Attempt to find another repository in the same registry to mount the layer from to avoid an unnecessary upload
	for _, metadata := range v2Metadata {
		sourceRepo, err := reference.ParseNamed(metadata.SourceRepository)
		if err != nil {
			continue
		}
		if pd.repoInfo.Hostname() == sourceRepo.Hostname() {
			logrus.Debugf("attempting to mount layer %s (%s) from %s", diffID, metadata.Digest, sourceRepo.FullName())
			mountFrom = metadata
			break
		}
	}

	var createOpts []distribution.BlobCreateOption

	if mountFrom.SourceRepository != "" {
		namedRef, err := reference.WithName(mountFrom.SourceRepository)
		if err != nil {
			return err
		}

		// TODO (brianbland): We need to construct a reference where the Name is
		// only the full remote name, so clean this up when distribution has a
		// richer reference package
		remoteRef, err := distreference.WithName(namedRef.RemoteName())
		if err != nil {
			return err
		}

		canonicalRef, err := distreference.WithDigest(remoteRef, mountFrom.Digest)
		if err != nil {
			return err
		}

		createOpts = append(createOpts, client.WithMountFrom(canonicalRef))
	}

	// Send the layer
	layerUpload, err := bs.Create(ctx, createOpts...)
	switch err := err.(type) {
	case distribution.ErrBlobMounted:
		progress.Updatef(progressOutput, pd.ID(), "Mounted from %s", err.From.Name())

		err.Descriptor.MediaType = schema2.MediaTypeLayer

		pd.pushState.Lock()
		pd.pushState.confirmedV2 = true
		pd.pushState.remoteLayers[diffID] = err.Descriptor
		pd.pushState.Unlock()

		// Cache mapping from this layer's DiffID to the blobsum
		if err := pd.v2MetadataService.Add(diffID, metadata.V2Metadata{Digest: mountFrom.Digest, SourceRepository: pd.repoInfo.FullName()}); err != nil {
			return xfer.DoNotRetry{Err: err}
		}

		return nil
	}
	if mountFrom.SourceRepository != "" {
		// unable to mount layer from this repository, so this source mapping is no longer valid
		logrus.Debugf("unassociating layer %s (%s) with %s", diffID, mountFrom.Digest, mountFrom.SourceRepository)
		pd.v2MetadataService.Remove(mountFrom)
	}
//.........这里部分代码省略.........

func migrateRefs(root, driverName string, rs refAdder, mappings map[string]image.ID) error {
	migrationFile := filepath.Join(root, migrationTagsFileName)
	if _, err := os.Lstat(migrationFile); !os.IsNotExist(err) {
		return err
	}

	type repositories struct {
		Repositories map[string]map[string]string
	}

	var repos repositories

	f, err := os.Open(filepath.Join(root, repositoriesFilePrefixLegacy+driverName))
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	defer f.Close()
	if err := json.NewDecoder(f).Decode(&repos); err != nil {
		return err
	}

	for name, repo := range repos.Repositories {
		for tag, id := range repo {
			if strongID, exists := mappings[id]; exists {
				ref, err := reference.WithName(name)
				if err != nil {
					logrus.Errorf("migrate tags: invalid name %q, %q", name, err)
					continue
				}
				if dgst, err := digest.ParseDigest(tag); err == nil {
					canonical, err := reference.WithDigest(ref, dgst)
					if err != nil {
						logrus.Errorf("migrate tags: invalid digest %q, %q", dgst, err)
						continue
					}
					if err := rs.AddDigest(canonical, strongID, false); err != nil {
						logrus.Errorf("can't migrate digest %q for %q, err: %q", ref.String(), strongID, err)
					}
				} else {
					tagRef, err := reference.WithTag(ref, tag)
					if err != nil {
						logrus.Errorf("migrate tags: invalid tag %q, %q", tag, err)
						continue
					}
					if err := rs.AddTag(tagRef, strongID, false); err != nil {
						logrus.Errorf("can't migrate tag %q for %q, err: %q", ref.String(), strongID, err)
					}
				}
				logrus.Infof("migrated tag %s:%s to point to %s", name, tag, strongID)
			}
		}
	}

	mf, err := os.Create(migrationFile)
	if err != nil {
		return err
	}
	mf.Close()

	return nil
}

//.........这里部分代码省略.........
			Index: &registrytypes.IndexInfo{
				Name:     "example.com:8000",
				Official: false,
			},
			RemoteName:    "privatebase",
			LocalName:     "example.com:8000/privatebase",
			CanonicalName: "example.com:8000/privatebase",
			Official:      false,
		},
		"localhost/private/moonbase": {
			Index: &registrytypes.IndexInfo{
				Name:     "localhost",
				Official: false,
			},
			RemoteName:    "private/moonbase",
			LocalName:     "localhost/private/moonbase",
			CanonicalName: "localhost/private/moonbase",
			Official:      false,
		},
		"localhost/privatebase": {
			Index: &registrytypes.IndexInfo{
				Name:     "localhost",
				Official: false,
			},
			RemoteName:    "privatebase",
			LocalName:     "localhost/privatebase",
			CanonicalName: "localhost/privatebase",
			Official:      false,
		},
		IndexName + "/public/moonbase": {
			Index: &registrytypes.IndexInfo{
				Name:     IndexName,
				Official: true,
			},
			RemoteName:    "public/moonbase",
			LocalName:     "public/moonbase",
			CanonicalName: "docker.io/public/moonbase",
			Official:      false,
		},
		"index." + IndexName + "/public/moonbase": {
			Index: &registrytypes.IndexInfo{
				Name:     IndexName,
				Official: true,
			},
			RemoteName:    "public/moonbase",
			LocalName:     "public/moonbase",
			CanonicalName: "docker.io/public/moonbase",
			Official:      false,
		},
		"ubuntu-12.04-base": {
			Index: &registrytypes.IndexInfo{
				Name:     IndexName,
				Official: true,
			},
			RemoteName:    "library/ubuntu-12.04-base",
			LocalName:     "ubuntu-12.04-base",
			CanonicalName: "docker.io/library/ubuntu-12.04-base",
			Official:      true,
		},
		IndexName + "/ubuntu-12.04-base": {
			Index: &registrytypes.IndexInfo{
				Name:     IndexName,
				Official: true,
			},
			RemoteName:    "library/ubuntu-12.04-base",
			LocalName:     "ubuntu-12.04-base",
			CanonicalName: "docker.io/library/ubuntu-12.04-base",
			Official:      true,
		},
		"index." + IndexName + "/ubuntu-12.04-base": {
			Index: &registrytypes.IndexInfo{
				Name:     IndexName,
				Official: true,
			},
			RemoteName:    "library/ubuntu-12.04-base",
			LocalName:     "ubuntu-12.04-base",
			CanonicalName: "docker.io/library/ubuntu-12.04-base",
			Official:      true,
		},
	}

	for reposName, expectedRepoInfo := range expectedRepoInfos {
		named, err := reference.WithName(reposName)
		if err != nil {
			t.Error(err)
		}

		repoInfo, err := ParseRepositoryInfo(named)
		if err != nil {
			t.Error(err)
		} else {
			checkEqual(t, repoInfo.Index.Name, expectedRepoInfo.Index.Name, reposName)
			checkEqual(t, repoInfo.RemoteName(), expectedRepoInfo.RemoteName, reposName)
			checkEqual(t, repoInfo.Name(), expectedRepoInfo.LocalName, reposName)
			checkEqual(t, repoInfo.FullName(), expectedRepoInfo.CanonicalName, reposName)
			checkEqual(t, repoInfo.Index.Official, expectedRepoInfo.Index.Official, reposName)
			checkEqual(t, repoInfo.Official, expectedRepoInfo.Official, reposName)
		}
	}
}