@@ -21,7 +21,7 @@ type Backend interface {

 }

 type containerBackend interface {

-	Commit(name string, config *backend.ContainerCommitConfig) (imageID string, err error)

+	CreateImageFromContainer(name string, config *backend.CreateImageConfig) (imageID string, err error)

 }

 type imageBackend interface {

@@ -34,33 +34,29 @@ func (s *imageRouter) postCommit(ctx context.Context, w http.ResponseWriter, r *

 		return err

 	}

-	cname := r.Form.Get("container")

-

+	// TODO: remove pause arg, and always pause in backend

 	pause := httputils.BoolValue(r, "pause")

 	version := httputils.VersionFromContext(ctx)

 	if r.FormValue("pause") == "" && versions.GreaterThanOrEqualTo(version, "1.13") {

 		pause = true

 	}

-	c, _, _, err := s.decoder.DecodeConfig(r.Body)

+	config, _, _, err := s.decoder.DecodeConfig(r.Body)

 	if err != nil && err != io.EOF { //Do not fail if body is empty.

 		return err

 	}

-	commitCfg := &backend.ContainerCommitConfig{

-		ContainerCommitConfig: types.ContainerCommitConfig{

-			Pause:        pause,

-			Repo:         r.Form.Get("repo"),

-			Tag:          r.Form.Get("tag"),

-			Author:       r.Form.Get("author"),

-			Comment:      r.Form.Get("comment"),

-			Config:       c,

-			MergeConfigs: true,

-		},

+	commitCfg := &backend.CreateImageConfig{

+		Pause:   pause,

+		Repo:    r.Form.Get("repo"),

+		Tag:     r.Form.Get("tag"),

+		Author:  r.Form.Get("author"),

+		Comment: r.Form.Get("comment"),

+		Config:  config,

 		Changes: r.Form["changes"],

 	}

-	imgID, err := s.backend.Commit(cname, commitCfg)

+	imgID, err := s.backend.CreateImageFromContainer(r.Form.Get("container"), commitCfg)

 	if err != nil {

 		return err

 	}

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

 	"io"

 	"time"

-	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/api/types/container"

 )

@@ -94,13 +93,26 @@ type ExecProcessConfig struct {

 	User       string   `json:"user,omitempty"`

 }

-// ContainerCommitConfig is a wrapper around

-// types.ContainerCommitConfig that also

-// transports configuration changes for a container.

-type ContainerCommitConfig struct {

-	types.ContainerCommitConfig

+// CreateImageConfig is the configuration for creating an image from a

+// container.

+type CreateImageConfig struct {

+	Repo    string

+	Tag     string

+	Pause   bool

+	Author  string

+	Comment string

+	Config  *container.Config

 	Changes []string

-	// TODO: ContainerConfig is only used by the dockerfile Builder, so remove it

-	// once the Builder has been updated to use a different interface

-	ContainerConfig *container.Config

+}

+

+// CommitConfig is the configuration for creating an image as part of a build.

+type CommitConfig struct {

+	Author              string

+	Comment             string

+	Config              *container.Config

+	ContainerConfig     *container.Config

+	ContainerID         string

+	ContainerMountLabel string

+	ContainerOS         string

+	ParentImageID       string

 }

@@ -25,19 +25,6 @@ type ContainerRmConfig struct {

 	ForceRemove, RemoveVolume, RemoveLink bool

 }

-// ContainerCommitConfig contains build configs for commit operation,

-// and is used when making a commit with the current state of the container.

-type ContainerCommitConfig struct {

-	Pause   bool

-	Repo    string

-	Tag     string

-	Author  string

-	Comment string

-	// merge container config into commit config before commit

-	MergeConfigs bool

-	Config       *container.Config

-}

-

 // ExecConfig is a small subset of the Config struct that holds the configuration

 // for the exec feature of docker.

 type ExecConfig struct {

@@ -11,6 +11,7 @@ import (

 	"github.com/docker/docker/api/types/backend"

 	"github.com/docker/docker/api/types/container"

 	containerpkg "github.com/docker/docker/container"

+	"github.com/docker/docker/image"

 	"github.com/docker/docker/layer"

 	"github.com/docker/docker/pkg/containerfs"

 	"golang.org/x/net/context"

@@ -39,8 +40,9 @@ type Backend interface {

 	ImageBackend

 	ExecBackend

-	// Commit creates a new Docker image from an existing Docker container.

-	Commit(string, *backend.ContainerCommitConfig) (string, error)

+	// CommitBuildStep creates a new Docker image from the config generated by

+	// a build step.

+	CommitBuildStep(backend.CommitConfig) (image.ID, error)

 	// ContainerCreateWorkdir creates the workdir

 	ContainerCreateWorkdir(containerID string) error

@@ -13,6 +13,7 @@ import (

 	"github.com/docker/docker/builder"

 	"github.com/docker/docker/builder/dockerfile/instructions"

 	"github.com/docker/docker/builder/dockerfile/shell"

+	"github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/system"

 	"github.com/docker/go-connections/nat"

 	"github.com/stretchr/testify/assert"

@@ -445,7 +446,7 @@ func TestRunWithBuildArgs(t *testing.T) {

 		assert.Equal(t, strslice.StrSlice{""}, config.Config.Entrypoint)

 		return container.ContainerCreateCreatedBody{ID: "12345"}, nil

 	}

-	mockBackend.commitFunc = func(cID string, cfg *backend.ContainerCommitConfig) (string, error) {

+	mockBackend.commitFunc = func(cfg backend.CommitConfig) (image.ID, error) {

 		// Check the runConfig.Cmd sent to commit()

 		assert.Equal(t, origCmd, cfg.Config.Cmd)

 		assert.Equal(t, cachedCmd, cfg.ContainerConfig.Cmd)

@@ -101,24 +101,17 @@ func (b *Builder) commitContainer(dispatchState *dispatchState, id string, conta

 		return nil

 	}

-	commitCfg := &backend.ContainerCommitConfig{

-		ContainerCommitConfig: types.ContainerCommitConfig{

-			Author: dispatchState.maintainer,

-			Pause:  true,

-			// TODO: this should be done by Commit()

-			Config: copyRunConfig(dispatchState.runConfig),

-		},

+	commitCfg := backend.CommitConfig{

+		Author: dispatchState.maintainer,

+		// TODO: this copy should be done by Commit()

+		Config:          copyRunConfig(dispatchState.runConfig),

 		ContainerConfig: containerConfig,

+		ContainerID:     id,

 	}

-	// Commit the container

-	imageID, err := b.docker.Commit(id, commitCfg)

-	if err != nil {

-		return err

-	}

-

-	dispatchState.imageID = imageID

-	return nil

+	imageID, err := b.docker.CommitBuildStep(commitCfg)

+	dispatchState.imageID = string(imageID)

+	return err

 }

 func (b *Builder) exportImage(state *dispatchState, imageMount *imageMount, runConfig *container.Config) error {

@@ -10,6 +10,7 @@ import (

 	"github.com/docker/docker/api/types/container"

 	"github.com/docker/docker/builder"

 	containerpkg "github.com/docker/docker/container"

+	"github.com/docker/docker/image"

 	"github.com/docker/docker/layer"

 	"github.com/docker/docker/pkg/containerfs"

 	"golang.org/x/net/context"

@@ -18,7 +19,7 @@ import (

 // MockBackend implements the builder.Backend interface for unit testing

 type MockBackend struct {

 	containerCreateFunc func(config types.ContainerCreateConfig) (container.ContainerCreateCreatedBody, error)

-	commitFunc          func(string, *backend.ContainerCommitConfig) (string, error)

+	commitFunc          func(backend.CommitConfig) (image.ID, error)

 	getImageFunc        func(string) (builder.Image, builder.ReleaseableLayer, error)

 	makeImageCacheFunc  func(cacheFrom []string) builder.ImageCache

 }

@@ -38,9 +39,9 @@ func (m *MockBackend) ContainerRm(name string, config *types.ContainerRmConfig)

 	return nil

 }

-func (m *MockBackend) Commit(cID string, cfg *backend.ContainerCommitConfig) (string, error) {

+func (m *MockBackend) CommitBuildStep(c backend.CommitConfig) (image.ID, error) {

 	if m.commitFunc != nil {

-		return m.commitFunc(cID, cfg)

+		return m.commitFunc(c)

 	}

 	return "", nil

 }

@@ -12,7 +12,6 @@ import (

 	"github.com/docker/docker/api/types/backend"

 	containertypes "github.com/docker/docker/api/types/container"

 	"github.com/docker/docker/builder/dockerfile"

-	"github.com/docker/docker/container"

 	"github.com/docker/docker/errdefs"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/layer"

@@ -122,9 +121,10 @@ func merge(userConf, imageConf *containertypes.Config) error {

 	return nil

 }

-// Commit creates a new filesystem image from the current state of a container.

-// The image can optionally be tagged into a repository.

-func (daemon *Daemon) Commit(name string, c *backend.ContainerCommitConfig) (string, error) {

+// CreateImageFromContainer creates a new image from a container. The container

+// config will be updated by applying the change set to the custom config, then

+// applying that config over the existing container config.

+func (daemon *Daemon) CreateImageFromContainer(name string, c *backend.CreateImageConfig) (string, error) {

 	start := time.Now()

 	container, err := daemon.GetContainer(name)

 	if err != nil {

@@ -150,26 +150,51 @@ func (daemon *Daemon) Commit(name string, c *backend.ContainerCommitConfig) (str

 		daemon.containerPause(container)

 		defer daemon.containerUnpause(container)

 	}

-	if !system.IsOSSupported(container.OS) {

-		return "", system.ErrNotSupportedOperatingSystem

-	}

-	if c.MergeConfigs && c.Config == nil {

+	if c.Config == nil {

 		c.Config = container.Config

 	}

-

 	newConfig, err := dockerfile.BuildFromConfig(c.Config, c.Changes, container.OS)

 	if err != nil {

 		return "", err

 	}

+	if err := merge(newConfig, container.Config); err != nil {

+		return "", err

+	}

-	if c.MergeConfigs {

-		if err := merge(newConfig, container.Config); err != nil {

-			return "", err

-		}

+	id, err := daemon.commitImage(backend.CommitConfig{

+		Author:              c.Author,

+		Comment:             c.Comment,

+		Config:              newConfig,

+		ContainerConfig:     container.Config,

+		ContainerID:         container.ID,

+		ContainerMountLabel: container.MountLabel,

+		ContainerOS:         container.OS,

+		ParentImageID:       string(container.ImageID),

+	})

+	if err != nil {

+		return "", err

 	}

-	rwTar, err := daemon.exportContainerRw(container)

+	imageRef, err := daemon.tagCommit(c.Repo, c.Tag, id)

+	if err != nil {

+		return "", err

+	}

+	daemon.LogContainerEventWithAttributes(container, "commit", map[string]string{

+		"comment":  c.Comment,

+		"imageID":  id.String(),

+		"imageRef": imageRef,

+	})

+	containerActions.WithValues("commit").UpdateSince(start)

+	return id.String(), nil

+}

+

+func (daemon *Daemon) commitImage(c backend.CommitConfig) (image.ID, error) {

+	layerStore, ok := daemon.layerStores[c.ContainerOS]

+	if !ok {

+		return "", system.ErrNotSupportedOperatingSystem

+	}

+	rwTar, err := exportContainerRw(layerStore, c.ContainerID, c.ContainerMountLabel)

 	if err != nil {

 		return "", err

 	}

@@ -180,35 +205,31 @@ func (daemon *Daemon) Commit(name string, c *backend.ContainerCommitConfig) (str

 	}()

 	var parent *image.Image

-	if container.ImageID == "" {

+	if c.ParentImageID == "" {

 		parent = new(image.Image)

 		parent.RootFS = image.NewRootFS()

 	} else {

-		parent, err = daemon.imageStore.Get(container.ImageID)

+		parent, err = daemon.imageStore.Get(image.ID(c.ParentImageID))

 		if err != nil {

 			return "", err

 		}

 	}

-	l, err := daemon.layerStores[container.OS].Register(rwTar, parent.RootFS.ChainID())

+	l, err := layerStore.Register(rwTar, parent.RootFS.ChainID())

 	if err != nil {

 		return "", err

 	}

-	defer layer.ReleaseAndLog(daemon.layerStores[container.OS], l)

+	defer layer.ReleaseAndLog(layerStore, l)

-	containerConfig := c.ContainerConfig

-	if containerConfig == nil {

-		containerConfig = container.Config

-	}

 	cc := image.ChildConfig{

-		ContainerID:     container.ID,

+		ContainerID:     c.ContainerID,

 		Author:          c.Author,

 		Comment:         c.Comment,

-		ContainerConfig: containerConfig,

-		Config:          newConfig,

+		ContainerConfig: c.ContainerConfig,

+		Config:          c.Config,

 		DiffID:          l.DiffID(),

 	}

-	config, err := json.Marshal(image.NewChildImage(parent, cc, container.OS))

+	config, err := json.Marshal(image.NewChildImage(parent, cc, c.ContainerOS))

 	if err != nil {

 		return "", err

 	}

@@ -218,23 +239,27 @@ func (daemon *Daemon) Commit(name string, c *backend.ContainerCommitConfig) (str

 		return "", err

 	}

-	if container.ImageID != "" {

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

+	if c.ParentImageID != "" {

+		if err := daemon.imageStore.SetParent(id, image.ID(c.ParentImageID)); err != nil {

 			return "", err

 		}

 	}

+	return id, nil

+}

+// TODO: remove from Daemon, move to api backend

+func (daemon *Daemon) tagCommit(repo string, tag string, id image.ID) (string, error) {

 	imageRef := ""

-	if c.Repo != "" {

-		newTag, err := reference.ParseNormalizedNamed(c.Repo) // todo: should move this to API layer

+	if repo != "" {

+		newTag, err := reference.ParseNormalizedNamed(repo) // todo: should move this to API layer

 		if err != nil {

 			return "", err

 		}

 		if !reference.IsNameOnly(newTag) {

-			return "", errors.Errorf("unexpected repository name: %s", c.Repo)

+			return "", errors.Errorf("unexpected repository name: %s", repo)

 		}

-		if c.Tag != "" {

-			if newTag, err = reference.WithTag(newTag, c.Tag); err != nil {

+		if tag != "" {

+			if newTag, err = reference.WithTag(newTag, tag); err != nil {

 				return "", err

 			}

 		}

@@ -243,26 +268,17 @@ func (daemon *Daemon) Commit(name string, c *backend.ContainerCommitConfig) (str

 		}

 		imageRef = reference.FamiliarString(newTag)

 	}

-

-	attributes := map[string]string{

-		"comment":  c.Comment,

-		"imageID":  id.String(),

-		"imageRef": imageRef,

-	}

-	daemon.LogContainerEventWithAttributes(container, "commit", attributes)

-	containerActions.WithValues("commit").UpdateSince(start)

-	return id.String(), nil

+	return imageRef, nil

 }

-func (daemon *Daemon) exportContainerRw(container *container.Container) (arch io.ReadCloser, err error) {

-	// Note: Indexing by OS is safe as only called from `Commit` which has already performed validation

-	rwlayer, err := daemon.layerStores[container.OS].GetRWLayer(container.ID)

+func exportContainerRw(layerStore layer.Store, id, mountLabel string) (arch io.ReadCloser, err error) {

+	rwlayer, err := layerStore.GetRWLayer(id)

 	if err != nil {

 		return nil, err

 	}

 	defer func() {

 		if err != nil {

-			daemon.layerStores[container.OS].ReleaseRWLayer(rwlayer)

+			layerStore.ReleaseRWLayer(rwlayer)

 		}

 	}()

@@ -270,7 +286,7 @@ func (daemon *Daemon) exportContainerRw(container *container.Container) (arch io

 	// mount the layer if needed. But the Diff() function for windows requests that

 	// the layer should be mounted when calling it. So we reserve this mount call

 	// until windows driver can implement Diff() interface correctly.

-	_, err = rwlayer.Mount(container.GetMountLabel())

+	_, err = rwlayer.Mount(mountLabel)

 	if err != nil {

 		return nil, err

 	}

@@ -283,8 +299,28 @@ func (daemon *Daemon) exportContainerRw(container *container.Container) (arch io

 	return ioutils.NewReadCloserWrapper(archive, func() error {

 			archive.Close()

 			err = rwlayer.Unmount()

-			daemon.layerStores[container.OS].ReleaseRWLayer(rwlayer)

+			layerStore.ReleaseRWLayer(rwlayer)

 			return err

 		}),

 		nil

 }

+

+// CommitBuildStep is used by the builder to create an image for each step in

+// the build.

+//

+// This method is different from CreateImageFromContainer:

+//   * it doesn't attempt to validate container state

+//   * it doesn't send a commit action to metrics

+//   * it doesn't log a container commit event

+//

+// This is a temporary shim. Should be removed when builder stops using commit.

+func (daemon *Daemon) CommitBuildStep(c backend.CommitConfig) (image.ID, error) {

+	container, err := daemon.GetContainer(c.ContainerID)

+	if err != nil {

+		return "", err

+	}

+	c.ContainerMountLabel = container.MountLabel

+	c.ContainerOS = container.OS

+	c.ParentImageID = string(container.ImageID)

+	return daemon.commitImage(c)

+}

@@ -601,7 +601,7 @@ func (s *DockerSuite) TestEventsFilterType(c *check.C) {

 	events = strings.Split(strings.TrimSpace(out), "\n")

 	// Events generated by the container that builds the image

-	c.Assert(events, checker.HasLen, 3, check.Commentf("Events == %s", events))

+	c.Assert(events, checker.HasLen, 2, check.Commentf("Events == %s", events))

 	out, _ = dockerCmd(

 		c,