Terminate template VMs on layer delete

Signed-off-by: Darren Stahl <darst@microsoft.com>

daemon/graphdriver/windows/windows.go

@@ -244,6 +244,32 @@ func (d *Driver) Remove(id string) error {
 		return err
 	}
 
+	// Get and terminate any template VMs that are currently using the layer
+	computeSystems, err := hcsshim.GetContainers(hcsshim.ComputeSystemQuery{})
+	if err != nil {
+		return err
+	}
+
+	for _, computeSystem := range computeSystems {
+		if strings.Contains(computeSystem.RuntimeImagePath, id) && computeSystem.IsRuntimeTemplate {
+			container, err := hcsshim.OpenContainer(computeSystem.ID)
+			if err != nil {
+				return err
+			}
+			defer container.Close()
+			err = container.Terminate()
+			if hcsshim.IsPending(err) {
+				err = container.Wait()
+			} else if hcsshim.IsAlreadyStopped(err) {
+				err = nil
+			}
+
+			if err != nil {
+				return err
+			}
+		}
+	}
+
 	layerPath := filepath.Join(d.info.HomeDir, rID)
 	tmpID := fmt.Sprintf("%s-removing", rID)
 	tmpLayerPath := filepath.Join(d.info.HomeDir, tmpID)