Rename IsMountPoint to IsLikelyNotMountPoint

IsLikelyNotMountPoint determines if a directory is not a mountpoint.
It is fast but not necessarily ALWAYS correct. If the path is in fact
a bind mount from one part of a mount to another it will not be detected.
mkdir /tmp/a /tmp/b; mount --bin /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b")
will return true. When in fact /tmp/b is a mount point. So this patch
renames the function and switches it from a positive to a negative (I
could think of a good positive name). This should make future users of
this function aware that it isn't quite perfect, but probably good
enough.

pkg/volume/gce_pd/gce_pd.go

@@ -172,12 +172,12 @@ func (b *gcePersistentDiskBuilder) SetUp() error {
 // SetUpAt attaches the disk and bind mounts to the volume path.
 func (b *gcePersistentDiskBuilder) SetUpAt(dir string) error {
 	// TODO: handle failed mounts here.
-	mountpoint, err := b.mounter.IsMountPoint(dir)
-	glog.V(4).Infof("PersistentDisk set up: %s %v %v", dir, mountpoint, err)
+	notMnt, err := b.mounter.IsLikelyNotMountPoint(dir)
+	glog.V(4).Infof("PersistentDisk set up: %s %v %v", dir, !notMnt, err)
 	if err != nil && !os.IsNotExist(err) {
 		return err
 	}
-	if mountpoint {
+	if !notMnt {
 		return nil
 	}
 
@@ -199,22 +199,22 @@ func (b *gcePersistentDiskBuilder) SetUpAt(dir string) error {
 	}
 	err = b.mounter.Mount(globalPDPath, dir, "", options)
 	if err != nil {
-		mountpoint, mntErr := b.mounter.IsMountPoint(dir)
+		notMnt, mntErr := b.mounter.IsLikelyNotMountPoint(dir)
 		if mntErr != nil {
-			glog.Errorf("isMountpoint check failed: %v", mntErr)
+			glog.Errorf("IsLikelyNotMountPoint check failed: %v", mntErr)
 			return err
 		}
-		if mountpoint {
+		if !notMnt {
 			if mntErr = b.mounter.Unmount(dir); mntErr != nil {
 				glog.Errorf("Failed to unmount: %v", mntErr)
 				return err
 			}
-			mountpoint, mntErr := b.mounter.IsMountPoint(dir)
+			notMnt, mntErr := b.mounter.IsLikelyNotMountPoint(dir)
 			if mntErr != nil {
-				glog.Errorf("isMountpoint check failed: %v", mntErr)
+				glog.Errorf("IsLikelyNotMountPoint check failed: %v", mntErr)
 				return err
 			}
-			if mountpoint {
+			if !notMnt {
 				// This is very odd, we don't expect it.  We'll try again next sync loop.
 				glog.Errorf("%s is still mounted, despite call to unmount().  Will try again next sync loop.", dir)
 				return err
@@ -257,11 +257,11 @@ func (c *gcePersistentDiskCleaner) TearDown() error {
 // Unmounts the bind mount, and detaches the disk only if the PD
 // resource was the last reference to that disk on the kubelet.
 func (c *gcePersistentDiskCleaner) TearDownAt(dir string) error {
-	mountpoint, err := c.mounter.IsMountPoint(dir)
+	notMnt, err := c.mounter.IsLikelyNotMountPoint(dir)
 	if err != nil {
 		return err
 	}
-	if !mountpoint {
+	if notMnt {
 		return os.Remove(dir)
 	}
 
@@ -282,12 +282,12 @@ func (c *gcePersistentDiskCleaner) TearDownAt(dir string) error {
 			return err
 		}
 	}
-	mountpoint, mntErr := c.mounter.IsMountPoint(dir)
+	notMnt, mntErr := c.mounter.IsLikelyNotMountPoint(dir)
 	if mntErr != nil {
-		glog.Errorf("isMountpoint check failed: %v", mntErr)
+		glog.Errorf("IsLikelyNotMountPoint check failed: %v", mntErr)
 		return err
 	}
-	if !mountpoint {
+	if notMnt {
 		if err := os.Remove(dir); err != nil {
 			return err
 		}

pkg/volume/gce_pd/gce_util.go

@@ -71,13 +71,13 @@ func (diskUtil *GCEDiskUtil) AttachAndMountDisk(b *gcePersistentDiskBuilder, glo
 	}
 
 	// Only mount the PD globally once.
-	mountpoint, err := b.mounter.IsMountPoint(globalPDPath)
+	notMnt, err := b.mounter.IsLikelyNotMountPoint(globalPDPath)
 	if err != nil {
 		if os.IsNotExist(err) {
 			if err := os.MkdirAll(globalPDPath, 0750); err != nil {
 				return err
 			}
-			mountpoint = false
+			notMnt = true
 		} else {
 			return err
 		}
@@ -86,7 +86,7 @@ func (diskUtil *GCEDiskUtil) AttachAndMountDisk(b *gcePersistentDiskBuilder, glo
 	if b.readOnly {
 		options = append(options, "ro")
 	}
-	if !mountpoint {
+	if notMnt {
 		err = b.diskMounter.Mount(devicePath, globalPDPath, b.fsType, options)
 		if err != nil {
 			os.Remove(globalPDPath)