diff --git a/builder/builder.go b/builder/builder.go
index bbf0a30e15..caff35aead 100644
--- a/builder/builder.go
+++ b/builder/builder.go
@@ -111,7 +111,7 @@ func (fi *HashedFileInfo) SetHash(h string) {
 type Backend interface {
 	// TODO: use digest reference instead of name
 
-	// LookupImage looks up a Docker image referenced by `name`.
+	// GetImage looks up a Docker image referenced by `name`.
 	GetImage(name string) (*image.Image, error)
 	// Pull tells Docker to pull image referenced by `name`.
 	Pull(name string) (*image.Image, error)
@@ -142,12 +142,11 @@ type Backend interface {
 	// TODO: use copyBackend api
 	BuilderCopy(containerID string, destPath string, src FileInfo, decompress bool) error
 
-	// Retain retains an image avoiding it to be removed or overwritten until a corresponding Release() call.
 	// TODO: remove
-	Retain(sessionID, imgID string)
-	// Release releases a list of images that were retained for the time of a build.
-	// TODO: remove
-	Release(sessionID string, activeImages []string)
+	// Mount mounts the root filesystem for the container.
+	Mount(containerID string) error
+	// Unmount unmounts the root filesystem for the container.
+	Unmount(containerID string) error
 }
 
 // ImageCache abstracts an image cache store.
diff --git a/builder/dockerfile/builder.go b/builder/dockerfile/builder.go
index 554e0c9558..5b254440eb 100644
--- a/builder/dockerfile/builder.go
+++ b/builder/dockerfile/builder.go
@@ -95,8 +95,7 @@ type Builder struct {
 	allowedBuildArgs map[string]bool // list of build-time args that are allowed for expansion/substitution and passing to commands in 'run'.
 
 	// TODO: remove once docker.Commit can receive a tag
-	id           string
-	activeImages []string
+	id string
 }
 
 // NewBuilder creates a new Dockerfile builder from an optional dockerfile and a Config.
@@ -145,11 +144,6 @@ func NewBuilder(config *Config, docker builder.Backend, context builder.Context,
 // * NOT tag the image, that is responsibility of the caller.
 //
 func (b *Builder) Build() (string, error) {
-	// TODO: remove once b.docker.Commit can take a tag parameter.
-	defer func() {
-		b.docker.Release(b.id, b.activeImages)
-	}()
-
 	// If Dockerfile was not parsed yet, extract it from the Context
 	if b.dockerfile == nil {
 		if err := b.readDockerfile(); err != nil {
diff --git a/builder/dockerfile/dispatchers.go b/builder/dockerfile/dispatchers.go
index 038a2c8c61..97f50bb4e9 100644
--- a/builder/dockerfile/dispatchers.go
+++ b/builder/dockerfile/dispatchers.go
@@ -399,6 +399,9 @@ func run(b *Builder, args []string, attributes map[string]bool, original string)
 		return err
 	}
 
+	b.docker.Mount(cID)
+	defer b.docker.Unmount(cID)
+
 	if err := b.run(cID); err != nil {
 		return err
 	}
diff --git a/builder/dockerfile/internals.go b/builder/dockerfile/internals.go
index 91b2c0eb02..0d87c12b04 100644
--- a/builder/dockerfile/internals.go
+++ b/builder/dockerfile/internals.go
@@ -66,6 +66,10 @@ func (b *Builder) commit(id string, autoCmd *stringutils.StrSlice, comment strin
 		if err != nil {
 			return err
 		}
+		if err := b.docker.Mount(id); err != nil {
+			return err
+		}
+		defer b.docker.Unmount(id)
 	}
 
 	// Note: Actually copy the struct
@@ -83,8 +87,6 @@ func (b *Builder) commit(id string, autoCmd *stringutils.StrSlice, comment strin
 	if err != nil {
 		return err
 	}
-	b.docker.Retain(b.id, imageID)
-	b.activeImages = append(b.activeImages, imageID)
 	b.image = imageID
 	return nil
 }
@@ -191,6 +193,10 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD
 	if err != nil {
 		return err
 	}
+	if err := b.docker.Mount(container.ID); err != nil {
+		return err
+	}
+	defer b.docker.Unmount(container.ID)
 	b.tmpContainers[container.ID] = struct{}{}
 
 	comment := fmt.Sprintf("%s %s in %s", cmdName, origPaths, dest)
@@ -471,10 +477,6 @@ func (b *Builder) probeCache() (bool, error) {
 	logrus.Debugf("[BUILDER] Use cached version: %s", b.runConfig.Cmd)
 	b.image = string(cache)
 
-	// TODO: remove once Commit can take a tag parameter.
-	b.docker.Retain(b.id, b.image)
-	b.activeImages = append(b.activeImages, b.image)
-
 	return true, nil
 }
 
diff --git a/daemon/daemonbuilder/builder.go b/daemon/daemonbuilder/builder.go
index 61d09f6a76..6da9896301 100644
--- a/daemon/daemonbuilder/builder.go
+++ b/daemon/daemonbuilder/builder.go
@@ -176,6 +176,25 @@ func (d Docker) BuilderCopy(cID string, destPath string, src builder.FileInfo, d
 	return fixPermissions(srcPath, destPath, rootUID, rootGID, destExists)
 }
 
+// Mount mounts the root filesystem for the container.
+func (d Docker) Mount(cID string) error {
+	c, err := d.Daemon.GetContainer(cID)
+	if err != nil {
+		return err
+	}
+	return d.Daemon.Mount(c)
+}
+
+// Unmount unmounts the root filesystem for the container.
+func (d Docker) Unmount(cID string) error {
+	c, err := d.Daemon.GetContainer(cID)
+	if err != nil {
+		return err
+	}
+	d.Daemon.Unmount(c)
+	return nil
+}
+
 // GetCachedImage returns a reference to a cached image whose parent equals `parent`
 // and runconfig equals `cfg`. A cache miss is expected to return an empty ID and a nil error.
 func (d Docker) GetCachedImage(imgID string, cfg *runconfig.Config) (string, error) {