From 67473c6d06f084f58467ef257e2de4b2c0161240 Mon Sep 17 00:00:00 2001
From: Vivek Goyal <vgoyal@redhat.com>
Date: Thu, 25 Jun 2015 17:33:20 -0400
Subject: [PATCH] overlay: Export metadata for container and image in
 docker-inspect

Export metadata for container and image in docker-inspect when overlay
graphdriver is in use. Right now it is done only for devicemapper graph
driver.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 daemon/graphdriver/overlay/overlay.go | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/daemon/graphdriver/overlay/overlay.go b/daemon/graphdriver/overlay/overlay.go
index 1fbe51ade0..6fdaaf1e7a 100644
--- a/daemon/graphdriver/overlay/overlay.go
+++ b/daemon/graphdriver/overlay/overlay.go
@@ -168,7 +168,31 @@ func (d *Driver) Status() [][2]string {
 }
 
 func (d *Driver) GetMetadata(id string) (map[string]string, error) {
-	return nil, nil
+	dir := d.dir(id)
+	if _, err := os.Stat(dir); err != nil {
+		return nil, err
+	}
+
+	metadata := make(map[string]string)
+
+	// If id has a root, it is an image
+	rootDir := path.Join(dir, "root")
+	if _, err := os.Stat(rootDir); err == nil {
+		metadata["RootDir"] = rootDir
+		return metadata, nil
+	}
+
+	lowerId, err := ioutil.ReadFile(path.Join(dir, "lower-id"))
+	if err != nil {
+		return nil, err
+	}
+
+	metadata["LowerDir"] = path.Join(d.dir(string(lowerId)), "root")
+	metadata["UpperDir"] = path.Join(dir, "upper")
+	metadata["WorkDir"] = path.Join(dir, "work")
+	metadata["MergedDir"] = path.Join(dir, "merged")
+
+	return metadata, nil
 }
 
 func (d *Driver) Cleanup() error {