Merge pull request #28006 from dmcgowan/clean-overlay2-layerstore

Cleanup invalid code in overlay2 and layer store

daemon/graphdriver/overlay2/overlay.go

@@ -412,7 +412,7 @@ func (d *Driver) getLowerDirs(id string) ([]string, error) {
 			if err != nil {
 				return nil, err
 			}
-			lowersArray = append(lowersArray, path.Clean(path.Join(d.home, "link", lp)))
+			lowersArray = append(lowersArray, path.Clean(path.Join(d.home, linkDir, lp)))
 		}
 	} else if !os.IsNotExist(err) {
 		return nil, err

layer/empty.go

@@ -24,7 +24,10 @@ func (el *emptyLayer) TarStream() (io.ReadCloser, error) {
 	return ioutil.NopCloser(buf), nil
 }
 
-func (el *emptyLayer) TarStreamFrom(ChainID) (io.ReadCloser, error) {
+func (el *emptyLayer) TarStreamFrom(p ChainID) (io.ReadCloser, error) {
+	if p == "" {
+		return el.TarStream()
+	}
 	return nil, fmt.Errorf("can't get parent tar stream of an empty layer")
 }