From 40e0c389887940c814f57f4b281e9621faa19c41 Mon Sep 17 00:00:00 2001
From: Serguei Bezverkhi <sbezverk@cisco.com>
Date: Tue, 30 Jan 2018 17:56:53 -0500
Subject: [PATCH] Cleaning up loopback removal process

---
 pkg/volume/fc/fc_util.go       | 18 ++++++++++--------
 pkg/volume/iscsi/iscsi_util.go | 15 ++++++++++-----
 pkg/volume/util/util.go        |  1 -
 pkg/volume/util/util_linux.go  |  8 +++++---
 4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/pkg/volume/fc/fc_util.go b/pkg/volume/fc/fc_util.go
index 5c13c2cad8..3eff48ee52 100644
--- a/pkg/volume/fc/fc_util.go
+++ b/pkg/volume/fc/fc_util.go
@@ -361,9 +361,10 @@ func (util *FCUtil) DetachBlockFCDisk(c fcDiskUnmapper, mapPath, devicePath stri
 	}
 	loop, err := volumeutil.BlockVolumePathHandler.GetLoopDevice(blkUtil, dstPath)
 	if err != nil {
-		glog.Warningf("fc: failed to get loopback for device: %v, err: %v", dstPath, err)
-	} else {
-		glog.V(4).Infof("fc: found loopback: %v", loop)
+		if err.Error() != volumeutil.ErrDeviceNotFound {
+			return fmt.Errorf("fc: failed to get loopback for destination path: %v, err: %v", dstPath, err)
+		}
+		glog.Warning("fc: loopback for destination path: %s not found", dstPath)
 	}
 
 	// Detach volume from kubelet node
@@ -386,11 +387,12 @@ func (util *FCUtil) DetachBlockFCDisk(c fcDiskUnmapper, mapPath, devicePath stri
 		glog.Errorf("fc: last error occurred during detach disk:\n%v", lastErr)
 		return lastErr
 	}
-
-	// The volume was successfully detached from node. We can safely remove the loopback.
-	err = volumeutil.BlockVolumePathHandler.RemoveLoopDevice(blkUtil, loop)
-	if err != nil {
-		return fmt.Errorf("fc: failed to remove loopback :%v, err: %v", loop, err)
+	if len(loop) != 0 {
+		// The volume was successfully detached from node. We can safely remove the loopback.
+		err = volumeutil.BlockVolumePathHandler.RemoveLoopDevice(blkUtil, loop)
+		if err != nil {
+			return fmt.Errorf("fc: failed to remove loopback :%v, err: %v", loop, err)
+		}
 	}
 	return nil
 }
diff --git a/pkg/volume/iscsi/iscsi_util.go b/pkg/volume/iscsi/iscsi_util.go
index cfecfe57f8..149e972986 100644
--- a/pkg/volume/iscsi/iscsi_util.go
+++ b/pkg/volume/iscsi/iscsi_util.go
@@ -521,17 +521,22 @@ func (util *ISCSIUtil) DetachBlockISCSIDisk(c iscsiDiskUnmapper, mapPath string)
 	blkUtil := volumeutil.NewBlockVolumePathHandler()
 	loop, err := volumeutil.BlockVolumePathHandler.GetLoopDevice(blkUtil, devicePath)
 	if err != nil {
-		return fmt.Errorf("failed to get loopback for device: %v, err: %v", devicePath, err)
+		if err.Error() != volumeutil.ErrDeviceNotFound {
+			return fmt.Errorf("failed to get loopback for device: %v, err: %v", devicePath, err)
+		}
+		glog.Warning("iscsi: loopback for device: %s not found", device)
 	}
 	// Detach a volume from kubelet node
 	err = util.detachISCSIDisk(c.exec, portals, iqn, iface, volName, initiatorName, found)
 	if err != nil {
 		return fmt.Errorf("failed to finish detachISCSIDisk, err: %v", err)
 	}
-	// The volume was successfully detached from node. We can safely remove the loopback.
-	err = volumeutil.BlockVolumePathHandler.RemoveLoopDevice(blkUtil, loop)
-	if err != nil {
-		return fmt.Errorf("failed to remove loopback :%v, err: %v", loop, err)
+	if len(loop) != 0 {
+		// The volume was successfully detached from node. We can safely remove the loopback.
+		err = volumeutil.BlockVolumePathHandler.RemoveLoopDevice(blkUtil, loop)
+		if err != nil {
+			return fmt.Errorf("failed to remove loopback :%v, err: %v", loop, err)
+		}
 	}
 	return nil
 }
diff --git a/pkg/volume/util/util.go b/pkg/volume/util/util.go
index 6b6528f8ab..bcb436e6f8 100644
--- a/pkg/volume/util/util.go
+++ b/pkg/volume/util/util.go
@@ -46,7 +46,6 @@ const (
 
 	ErrDeviceNotFound     = "device not found"
 	ErrDeviceNotSupported = "device not supported"
-	ErrNotAvailable       = "not available"
 )
 
 // IsReady checks for the existence of a regular file
diff --git a/pkg/volume/util/util_linux.go b/pkg/volume/util/util_linux.go
index 755a10f012..f4bbe856a8 100644
--- a/pkg/volume/util/util_linux.go
+++ b/pkg/volume/util/util_linux.go
@@ -51,7 +51,7 @@ func (v VolumePathHandler) AttachFileDevice(path string) (string, error) {
 func (v VolumePathHandler) GetLoopDevice(path string) (string, error) {
 	_, err := os.Stat(path)
 	if os.IsNotExist(err) {
-		return "", errors.New(ErrNotAvailable)
+		return "", errors.New(ErrDeviceNotFound)
 	}
 	if err != nil {
 		return "", fmt.Errorf("not attachable: %v", err)
@@ -84,9 +84,11 @@ func (v VolumePathHandler) RemoveLoopDevice(device string) error {
 	cmd := exec.Command(losetupPath, args...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
-		if !strings.Contains(string(out), "No such device or address") {
-			return err
+		if _, err := os.Stat(device); os.IsNotExist(err) {
+			return nil
 		}
+		glog.V(2).Infof("Failed to remove loopback device: %s: %v %s", device, err, out)
+		return err
 	}
 	return nil
 }