@@ -75,7 +75,6 @@ type daemonStore struct {

 	imageStore                image.Store

 	layerStore                layer.Store

 	distributionMetadataStore dmetadata.Store

-	referenceStore            refstore.Store

 }

 // Daemon holds information about the Docker daemon.

@@ -103,7 +102,8 @@ type Daemon struct {

 	shutdown              bool

 	idMappings            *idtools.IDMappings

 	stores                map[string]daemonStore // By container target platform

-	PluginStore           *plugin.Store          // todo: remove

+	referenceStore        refstore.Store

+	PluginStore           *plugin.Store // todo: remove

 	pluginManager         *plugin.Manager

 	linkIndex             *linkIndex

 	containerd            libcontainerd.Client

@@ -691,7 +691,6 @@ func NewDaemon(config *config.Config, registryService registry.Service, containe

 	d.downloadManager = xfer.NewLayerDownloadManager(lsMap, *config.MaxConcurrentDownloads)

 	logrus.Debugf("Max Concurrent Uploads: %d", *config.MaxConcurrentUploads)

 	d.uploadManager = xfer.NewLayerUploadManager(*config.MaxConcurrentUploads)

-

 	for platform, ds := range d.stores {

 		imageRoot := filepath.Join(config.Root, "image", ds.graphDriver)

 		ifs, err := image.NewFSStoreBackend(filepath.Join(imageRoot, "imagedb"))

@@ -728,18 +727,30 @@ func NewDaemon(config *config.Config, registryService registry.Service, containe

 	eventsService := events.New()

+	// We have a single tag/reference store for the daemon globally. However, it's

+	// stored under the graphdriver. On host platforms which only support a single

+	// container OS, but multiple selectable graphdrivers, this means depending on which

+	// graphdriver is chosen, the global reference store is under there. For

+	// platforms which support multiple container operating systems, this is slightly

+	// more problematic as where does the global ref store get located? Fortunately,

+	// for Windows, which is currently the only daemon supporting multiple container

+	// operating systems, the list of graphdrivers available isn't user configurable.

+	// For backwards compatibility, we just put it under the windowsfilter

+	// directory regardless.

+	refStoreLocation := filepath.Join(d.stores[runtime.GOOS].imageRoot, `repositories.json`)

+	rs, err := refstore.NewReferenceStore(refStoreLocation)

+	if err != nil {

+		return nil, fmt.Errorf("Couldn't create reference store repository: %s", err)

+	}

+	d.referenceStore = rs

+

 	for platform, ds := range d.stores {

 		dms, err := dmetadata.NewFSMetadataStore(filepath.Join(ds.imageRoot, "distribution"), platform)

 		if err != nil {

 			return nil, err

 		}

-		rs, err := refstore.NewReferenceStore(filepath.Join(ds.imageRoot, "repositories.json"), platform)

-		if err != nil {

-			return nil, fmt.Errorf("Couldn't create Tag store repositories: %s", err)

-		}

 		ds.distributionMetadataStore = dms

-		ds.referenceStore = rs

 		d.stores[platform] = ds

 		// No content-addressability migration on Windows as it never supported pre-CA

@@ -20,7 +20,7 @@ func (daemon *Daemon) getLayerRefs(platform string) map[layer.ChainID]int {

 	layerRefs := map[layer.ChainID]int{}

 	for id, img := range tmpImages {

 		dgst := digest.Digest(id)

-		if len(daemon.stores[platform].referenceStore.References(dgst)) == 0 && len(daemon.stores[platform].imageStore.Children(id)) != 0 {

+		if len(daemon.referenceStore.References(dgst)) == 0 && len(daemon.stores[platform].imageStore.Children(id)) != 0 {

 			continue

 		}

@@ -2,6 +2,7 @@ package daemon

 import (

 	"fmt"

+	"runtime"

 	"github.com/docker/distribution/reference"

 	"github.com/docker/docker/image"

@@ -45,10 +46,17 @@ func (daemon *Daemon) GetImageIDAndPlatform(refOrID string) (image.ID, string, e

 		return "", "", errImageDoesNotExist{ref}

 	}

-	for platform := range daemon.stores {

-		if id, err := daemon.stores[platform].referenceStore.Get(namedRef); err == nil {

-			return image.IDFromDigest(id), platform, nil

+	if digest, err := daemon.referenceStore.Get(namedRef); err == nil {

+		// Search the image stores to get the platform, defaulting to host OS.

+		imagePlatform := runtime.GOOS

+		id := image.IDFromDigest(digest)

+		for platform := range daemon.stores {

+			if img, err := daemon.stores[platform].imageStore.Get(id); err == nil {

+				imagePlatform = img.Platform()

+				break

+			}

 		}

+		return id, imagePlatform, nil

 	}

 	// deprecated: repo:shortid https://github.com/docker/docker/pull/799

@@ -56,7 +64,7 @@ func (daemon *Daemon) GetImageIDAndPlatform(refOrID string) (image.ID, string, e

 		if tag := tagged.Tag(); stringid.IsShortID(stringid.TruncateID(tag)) {

 			for platform := range daemon.stores {

 				if id, err := daemon.stores[platform].imageStore.Search(tag); err == nil {

-					for _, storeRef := range daemon.stores[platform].referenceStore.References(id.Digest()) {

+					for _, storeRef := range daemon.referenceStore.References(id.Digest()) {

 						if storeRef.Name() == namedRef.Name() {

 							return id, platform, nil

 						}

@@ -70,7 +70,7 @@ func (daemon *Daemon) ImageDelete(imageRef string, force, prune bool) ([]types.I

 		return nil, err

 	}

-	repoRefs := daemon.stores[platform].referenceStore.References(imgID.Digest())

+	repoRefs := daemon.referenceStore.References(imgID.Digest())

 	var removedRepositoryRef bool

 	if !isImageIDPrefix(imgID.String(), imageRef) {

@@ -104,7 +104,7 @@ func (daemon *Daemon) ImageDelete(imageRef string, force, prune bool) ([]types.I

 		daemon.LogImageEvent(imgID.String(), imgID.String(), "untag")

 		records = append(records, untaggedRecord)

-		repoRefs = daemon.stores[platform].referenceStore.References(imgID.Digest())

+		repoRefs = daemon.referenceStore.References(imgID.Digest())

 		// If a tag reference was removed and the only remaining

 		// references to the same repository are digest references,

@@ -237,7 +237,7 @@ func (daemon *Daemon) removeImageRef(platform string, ref reference.Named) (refe

 	// Ignore the boolean value returned, as far as we're concerned, this

 	// is an idempotent operation and it's okay if the reference didn't

 	// exist in the first place.

-	_, err := daemon.stores[platform].referenceStore.Delete(ref)

+	_, err := daemon.referenceStore.Delete(ref)

 	return ref, err

 }

@@ -248,7 +248,7 @@ func (daemon *Daemon) removeImageRef(platform string, ref reference.Named) (refe

 // daemon's event service. An "Untagged" types.ImageDeleteResponseItem is added to the

 // given list of records.

 func (daemon *Daemon) removeAllReferencesToImageID(imgID image.ID, platform string, records *[]types.ImageDeleteResponseItem) error {

-	imageRefs := daemon.stores[platform].referenceStore.References(imgID.Digest())

+	imageRefs := daemon.referenceStore.References(imgID.Digest())

 	for _, imageRef := range imageRefs {

 		parsedRef, err := daemon.removeImageRef(platform, imageRef)

@@ -383,7 +383,7 @@ func (daemon *Daemon) checkImageDeleteConflict(imgID image.ID, platform string,

 	}

 	// Check if any repository tags/digest reference this image.

-	if mask&conflictActiveReference != 0 && len(daemon.stores[platform].referenceStore.References(imgID.Digest())) > 0 {

+	if mask&conflictActiveReference != 0 && len(daemon.referenceStore.References(imgID.Digest())) > 0 {

 		return &imageDeleteConflict{

 			imgID:   imgID,

 			message: "image is referenced in multiple repositories",

@@ -411,5 +411,5 @@ func (daemon *Daemon) checkImageDeleteConflict(imgID image.ID, platform string,

 // that there are no repository references to the given image and it has no

 // child images.

 func (daemon *Daemon) imageIsDangling(imgID image.ID, platform string) bool {

-	return !(len(daemon.stores[platform].referenceStore.References(imgID.Digest())) > 0 || len(daemon.stores[platform].imageStore.Children(imgID)) > 0)

+	return !(len(daemon.referenceStore.References(imgID.Digest())) > 0 || len(daemon.stores[platform].imageStore.Children(imgID)) > 0)

 }

@@ -19,7 +19,7 @@ func (daemon *Daemon) ExportImage(names []string, outStream io.Writer) error {

 	if system.LCOWSupported() {

 		platform = "linux"

 	}

-	imageExporter := tarexport.NewTarExporter(daemon.stores[platform].imageStore, daemon.stores[platform].layerStore, daemon.stores[platform].referenceStore, daemon)

+	imageExporter := tarexport.NewTarExporter(daemon.stores[platform].imageStore, daemon.stores[platform].layerStore, daemon.referenceStore, daemon)

 	return imageExporter.Save(names, outStream)

 }

@@ -32,6 +32,6 @@ func (daemon *Daemon) LoadImage(inTar io.ReadCloser, outStream io.Writer, quiet

 	if system.LCOWSupported() {

 		platform = "linux"

 	}

-	imageExporter := tarexport.NewTarExporter(daemon.stores[platform].imageStore, daemon.stores[platform].layerStore, daemon.stores[platform].referenceStore, daemon)

+	imageExporter := tarexport.NewTarExporter(daemon.stores[platform].imageStore, daemon.stores[platform].layerStore, daemon.referenceStore, daemon)

 	return imageExporter.Load(inTar, outStream, quiet)

 }

@@ -69,7 +69,7 @@ func (daemon *Daemon) ImageHistory(name string) ([]*image.HistoryResponseItem, e

 		h.ID = id.String()

 		var tags []string

-		for _, r := range daemon.stores[platform].referenceStore.References(id.Digest()) {

+		for _, r := range daemon.referenceStore.References(id.Digest()) {

 			if _, ok := r.(reference.NamedTagged); ok {

 				tags = append(tags, reference.FamiliarString(r))

 			}

@@ -24,7 +24,7 @@ func (daemon *Daemon) LookupImage(name string) (*types.ImageInspect, error) {

 		platform = runtime.GOOS

 	}

-	refs := daemon.stores[platform].referenceStore.References(img.ID().Digest())

+	refs := daemon.referenceStore.References(img.ID().Digest())

 	repoTags := []string{}

 	repoDigests := []string{}

 	for _, ref := range refs {

@@ -74,7 +74,7 @@ func (daemon *Daemon) pullImageWithReference(ctx context.Context, ref reference.

 			ImageEventLogger: daemon.LogImageEvent,

 			MetadataStore:    daemon.stores[platform].distributionMetadataStore,

 			ImageStore:       distribution.NewImageConfigStoreFromStore(daemon.stores[platform].imageStore),

-			ReferenceStore:   daemon.stores[platform].referenceStore,

+			ReferenceStore:   daemon.referenceStore,

 		},

 		DownloadManager: daemon.downloadManager,

 		Schema2Types:    distribution.ImageTypes,

@@ -56,7 +56,7 @@ func (daemon *Daemon) PushImage(ctx context.Context, image, tag string, metaHead

 			ImageEventLogger: daemon.LogImageEvent,

 			MetadataStore:    daemon.stores[platform].distributionMetadataStore,

 			ImageStore:       distribution.NewImageConfigStoreFromStore(daemon.stores[platform].imageStore),

-			ReferenceStore:   daemon.stores[platform].referenceStore,

+			ReferenceStore:   daemon.referenceStore,

 		},

 		ConfigMediaType: schema2.MediaTypeImageConfig,

 		LayerStore:      distribution.NewLayerProviderFromStore(daemon.stores[platform].layerStore),

@@ -28,7 +28,7 @@ func (daemon *Daemon) TagImage(imageName, repository, tag string) error {

 // TagImageWithReference adds the given reference to the image ID provided.

 func (daemon *Daemon) TagImageWithReference(imageID image.ID, platform string, newTag reference.Named) error {

-	if err := daemon.stores[platform].referenceStore.AddTag(newTag, imageID.Digest(), true); err != nil {

+	if err := daemon.referenceStore.AddTag(newTag, imageID.Digest(), true); err != nil {

 		return err

 	}

@@ -149,7 +149,7 @@ func (daemon *Daemon) Images(imageFilters filters.Args, all bool, withExtraAttrs

 		newImage := newImage(img, size)

-		for _, ref := range daemon.stores[platform].referenceStore.References(id.Digest()) {

+		for _, ref := range daemon.referenceStore.References(id.Digest()) {

 			if imageFilters.Include("reference") {

 				var found bool

 				var matchErr error

@@ -221,7 +221,7 @@ func (daemon *Daemon) ImagesPrune(ctx context.Context, pruneFilters filters.Args

 			return nil, ctx.Err()

 		default:

 			dgst := digest.Digest(id)

-			if len(daemon.stores[platform].referenceStore.References(dgst)) == 0 && len(daemon.stores[platform].imageStore.Children(id)) != 0 {

+			if len(daemon.referenceStore.References(dgst)) == 0 && len(daemon.stores[platform].imageStore.Children(id)) != 0 {

 				continue

 			}

 			if !until.IsZero() && img.Created.After(until) {

@@ -252,7 +252,7 @@ deleteImagesLoop:

 		}

 		deletedImages := []types.ImageDeleteResponseItem{}

-		refs := daemon.stores[platform].referenceStore.References(dgst)

+		refs := daemon.referenceStore.References(dgst)

 		if len(refs) > 0 {

 			shouldDelete := !danglingOnly

 			if !shouldDelete {

@@ -26,7 +26,7 @@ type Association struct {

 	ID  digest.Digest

 }

-// Store provides the set of methods which can operate on a tag store.

+// Store provides the set of methods which can operate on a reference store.

 type Store interface {

 	References(id digest.Digest) []reference.Named

 	ReferencesByName(ref reference.Named) []Association

@@ -46,9 +46,6 @@ type store struct {

 	// referencesByIDCache is a cache of references indexed by ID, to speed

 	// up References.

 	referencesByIDCache map[digest.Digest]map[string]reference.Named

-	// platform is the container target platform for this store (which may be

-	// different to the host operating system

-	platform string

 }

 // Repository maps tags to digests. The key is a stringified Reference,

@@ -73,7 +70,7 @@ func (a lexicalAssociations) Less(i, j int) bool {

 // NewReferenceStore creates a new reference store, tied to a file path where

 // the set of references are serialized in JSON format.

-func NewReferenceStore(jsonPath, platform string) (Store, error) {

+func NewReferenceStore(jsonPath string) (Store, error) {

 	abspath, err := filepath.Abs(jsonPath)

 	if err != nil {

 		return nil, err

@@ -83,7 +80,6 @@ func NewReferenceStore(jsonPath, platform string) (Store, error) {

 		jsonPath:            abspath,

 		Repositories:        make(map[string]repository),

 		referencesByIDCache: make(map[digest.Digest]map[string]reference.Named),

-		platform:            platform,

 	}

 	// Load the json file if it exists, otherwise create it.

 	if err := store.reload(); os.IsNotExist(err) {

@@ -5,7 +5,6 @@ import (

 	"io/ioutil"

 	"os"

 	"path/filepath"

-	"runtime"

 	"strings"

 	"testing"

@@ -41,7 +40,7 @@ func TestLoad(t *testing.T) {

 	}

 	jsonFile.Close()

-	store, err := NewReferenceStore(jsonFile.Name(), runtime.GOOS)

+	store, err := NewReferenceStore(jsonFile.Name())

 	if err != nil {

 		t.Fatalf("error creating tag store: %v", err)

 	}

@@ -70,7 +69,7 @@ func TestSave(t *testing.T) {

 	jsonFile.Close()

 	defer os.RemoveAll(jsonFile.Name())

-	store, err := NewReferenceStore(jsonFile.Name(), runtime.GOOS)

+	store, err := NewReferenceStore(jsonFile.Name())

 	if err != nil {

 		t.Fatalf("error creating tag store: %v", err)

 	}

@@ -112,7 +111,7 @@ func TestAddDeleteGet(t *testing.T) {

 	jsonFile.Close()

 	defer os.RemoveAll(jsonFile.Name())

-	store, err := NewReferenceStore(jsonFile.Name(), runtime.GOOS)

+	store, err := NewReferenceStore(jsonFile.Name())

 	if err != nil {

 		t.Fatalf("error creating tag store: %v", err)

 	}

@@ -329,7 +328,7 @@ func TestInvalidTags(t *testing.T) {

 	tmpDir, err := ioutil.TempDir("", "tag-store-test")

 	defer os.RemoveAll(tmpDir)

-	store, err := NewReferenceStore(filepath.Join(tmpDir, "repositories.json"), runtime.GOOS)

+	store, err := NewReferenceStore(filepath.Join(tmpDir, "repositories.json"))

 	if err != nil {

 		t.Fatalf("error creating tag store: %v", err)

 	}