[optimization]optimize TarStream for overlay2

daemon/graphdriver/overlay2/overlay.go

@@ -546,6 +546,12 @@ func (d *Driver) Remove(id string) error {
 	return nil
 }
 
+//GetDiffPath return the diff directory
+func (d *Driver) GetDiffPath(id string) containerfs.ContainerFS {
+	diffPath := path.Join(d.dir(id), "diff")
+	return containerfs.NewLocalContainerFS(diffPath)
+}
+
 // Get creates and mounts the required file system for the given id and returns the mount path.
 func (d *Driver) Get(id, mountLabel string) (_ containerfs.ContainerFS, retErr error) {
 	d.locker.Lock(id)

layer/layer_store.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/docker/distribution"
 	"github.com/docker/docker/daemon/graphdriver"
+	"github.com/docker/docker/pkg/containerfs"
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/plugingetter"
 	"github.com/docker/docker/pkg/stringid"
@@ -738,18 +739,34 @@ type naiveDiffPathDriver struct {
 
 type fileGetPutter struct {
 	storage.FileGetter
-	driver graphdriver.Driver
-	id     string
+	driver     graphdriver.Driver
+	id         string
+	isOverlay2 bool
 }
 
 func (w *fileGetPutter) Close() error {
+	if w.isOverlay2 {
+		//do nothing
+		return nil
+	}
 	return w.driver.Put(w.id)
 }
 
 func (n *naiveDiffPathDriver) DiffGetter(id string) (graphdriver.FileGetCloser, error) {
-	p, err := n.Driver.Get(id, "")
-	if err != nil {
-		return nil, err
+
+	var p containerfs.ContainerFS
+	isOverlay2 := false
+	if inter, ok := n.Driver.(interface {
+		GetDiffPath(id string) containerfs.ContainerFS
+	}); ok {
+		p = inter.GetDiffPath(id)
+		isOverlay2 = true
+	} else {
+		var err error
+		p, err = n.Driver.Get(id, "")
+		if err != nil {
+			return nil, err
+		}
 	}
-	return &fileGetPutter{storage.NewPathFileGetter(p.Path()), n.Driver, id}, nil
+	return &fileGetPutter{storage.NewPathFileGetter(p.Path()), n.Driver, id, isOverlay2}, nil
 }