From f3bca888f89ffed04d08db6b05d4c9a7d4c85b22 Mon Sep 17 00:00:00 2001
From: Seth Jennings <sjenning@redhat.com>
Date: Thu, 9 Jun 2016 15:24:26 -0500
Subject: [PATCH] fallback to /dev/mapper device if metadata device is not set
 in docker info

---
 utils/docker/docker.go | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/utils/docker/docker.go b/utils/docker/docker.go
index 568bd121..3ae62797 100644
--- a/utils/docker/docker.go
+++ b/utils/docker/docker.go
@@ -16,6 +16,7 @@ package docker
 
 import (
 	"fmt"
+	"os"
 	"strings"
 
 	dockertypes "github.com/docker/engine-api/types"
@@ -50,8 +51,19 @@ func DockerThinPoolName(info dockertypes.Info) (string, error) {
 
 func DockerMetadataDevice(info dockertypes.Info) (string, error) {
 	metadataDevice := DriverStatusValue(info.DriverStatus, DriverStatusMetadataFile)
-	if len(metadataDevice) == 0 {
-		return "", fmt.Errorf("Could not get the devicemapper metadata device")
+	if len(metadataDevice) != 0 {
+		return metadataDevice, nil
+	}
+
+	poolName, err := DockerThinPoolName(info)
+	if err != nil {
+		return "", err
+	}
+
+	metadataDevice = fmt.Sprintf("/dev/mapper/%s_tmeta", poolName)
+
+	if _, err := os.Stat(metadataDevice); err != nil {
+		return "", err
 	}
 
 	return metadataDevice, nil