From 98392532335407f948ade593cb8cd777673600ec Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Mon, 25 May 2015 08:13:30 -0400
Subject: [PATCH] Add logging to volume tear-down to help understand mount
 behaviour

---
 pkg/util/mount/mount.go       | 12 +++++++++---
 pkg/volume/aws_ebs/aws_ebs.go |  5 +++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/pkg/util/mount/mount.go b/pkg/util/mount/mount.go
index 9733f5a02eb..73311749b48 100644
--- a/pkg/util/mount/mount.go
+++ b/pkg/util/mount/mount.go
@@ -18,6 +18,8 @@ limitations under the License.
 // an alternate platform, we will need to abstract further.
 package mount
 
+import "github.com/golang/glog"
+
 type Interface interface {
 	// Mount mounts source to target as fstype with given options.
 	Mount(source string, target string, fstype string, options []string) error
@@ -66,9 +68,13 @@ func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
 
 	// Find all references to the device.
 	var refs []string
-	for i := range mps {
-		if mps[i].Device == deviceName && mps[i].Path != mountPath {
-			refs = append(refs, mps[i].Path)
+	if deviceName == "" {
+		glog.Warningf("could not determine device for path: %s", mountPath)
+	} else {
+		for i := range mps {
+			if mps[i].Device == deviceName && mps[i].Path != mountPath {
+				refs = append(refs, mps[i].Path)
+			}
 		}
 	}
 	return refs, nil
diff --git a/pkg/volume/aws_ebs/aws_ebs.go b/pkg/volume/aws_ebs/aws_ebs.go
index f276db68e31..b10ed14a422 100644
--- a/pkg/volume/aws_ebs/aws_ebs.go
+++ b/pkg/volume/aws_ebs/aws_ebs.go
@@ -289,6 +289,9 @@ func (pd *awsElasticBlockStore) TearDownAt(dir string) error {
 		glog.V(2).Info("Error getting mountrefs for ", dir, ": ", err)
 		return err
 	}
+	if len(refs) == 0 {
+		glog.Warning("Did not find pod-mount for ", dir, " during tear-down")
+	}
 	// Unmount the bind-mount inside this pod
 	if err := pd.mounter.Unmount(dir); err != nil {
 		glog.V(2).Info("Error unmounting dir ", dir, ": ", err)
@@ -307,6 +310,8 @@ func (pd *awsElasticBlockStore) TearDownAt(dir string) error {
 			glog.V(2).Info("Error detaching disk ", pd.volumeID, ": ", err)
 			return err
 		}
+	} else {
+		glog.V(2).Infof("Found multiple refs; won't detach EBS volume: %v", refs)
 	}
 	mountpoint, mntErr := pd.mounter.IsMountPoint(dir)
 	if mntErr != nil {