Add force to umount to force the umount of a container image

Signed-off-by: Daniel J Walsh <[email protected]>

cmd/containers-storage/copy.go

@@ -59,7 +59,7 @@ func copyContent(flags *mflag.FlagSet, action string, m storage.Store, args []st
 			return 1
 		}
 		target = filepath.Join(targetMount, targetParts[1])
-		defer m.Unmount(targetLayer.ID)
+		defer m.Unmount(targetLayer.ID, false)
 	}
 	args = args[:len(args)-1]
 	for _, srcSpec := range args {
@@ -83,7 +83,7 @@ func copyContent(flags *mflag.FlagSet, action string, m storage.Store, args []st
 				return 1
 			}
 			source = filepath.Join(sourceMount, sourceParts[1])
-			defer m.Unmount(sourceLayer.ID)
+			defer m.Unmount(sourceLayer.ID, false)
 		}
 		archiver := chrootarchive.NewArchiverWithChown(tarIDMappings, chownOpts, untarIDMappings)
 		if err := archiver.CopyWithTar(source, target); err != nil {

cmd/containers-storage/mount.go

@@ -51,7 +51,7 @@ func unmount(flags *mflag.FlagSet, action string, m storage.Store, args []string
 	mes := []mountPointError{}
 	errors := false
 	for _, arg := range args {
-		err := m.Unmount(arg)
+		err := m.Unmount(arg, false)
 		errText := ""
 		if err != nil {
 			errText = fmt.Sprintf("%v", err)

layers.go

@@ -211,7 +211,7 @@ type LayerStore interface {
 	Mount(id, mountLabel string) (string, error)
 
 	// Unmount unmounts a layer when it is no longer in use.
-	Unmount(id string) error
+	Unmount(id string, force bool) error
 
 	// ParentOwners returns the UIDs and GIDs of parents of the layer's mountpoint
 	// for which the layer's UID and GID maps don't contain corresponding entries.
@@ -652,7 +652,7 @@ func (r *layerStore) Mount(id, mountLabel string) (string, error) {
 	return mountpoint, err
 }
 
-func (r *layerStore) Unmount(id string) error {
+func (r *layerStore) Unmount(id string, force bool) error {
 	if !r.IsReadWrite() {
 		return errors.Wrapf(ErrStoreIsReadOnly, "not allowed to update mount locations for layers at %q", r.mountspath())
 	}
@@ -664,6 +664,9 @@ func (r *layerStore) Unmount(id string) error {
 		}
 		layer = layerByMount
 	}
+	if force {
+		layer.MountCount = 1
+	}
 	if layer.MountCount > 1 {
 		layer.MountCount--
 		return r.Save()
@@ -797,10 +800,8 @@ func (r *layerStore) Delete(id string) error {
 		return ErrLayerUnknown
 	}
 	id = layer.ID
-	for layer.MountCount > 0 {
-		if err := r.Unmount(id); err != nil {
-			return err
-		}
+	if err := r.Unmount(id, true); err != nil {
+		return err
 	}
 	err := r.driver.Remove(id)
 	if err == nil {
@@ -917,7 +918,7 @@ func (s *simpleGetCloser) Get(path string) (io.ReadCloser, error) {
 }
 
 func (s *simpleGetCloser) Close() error {
-	return s.r.Unmount(s.id)
+	return s.r.Unmount(s.id, false)
 }
 
 func (r *layerStore) newFileGetter(id string) (drivers.FileGetCloser, error) {

store.go

@@ -263,7 +263,7 @@ type Store interface {
 
 	// Unmount attempts to unmount a layer, image, or container, given an ID, a
 	// name, or a mount path.
-	Unmount(id string) error
+	Unmount(id string, force bool) error
 
 	// Changes returns a summary of the changes which would need to be made
 	// to one layer to make its contents the same as a second layer.  If
@@ -2245,7 +2245,7 @@ func (s *store) Mount(id, mountLabel string) (string, error) {
 	return "", ErrLayerUnknown
 }
 
-func (s *store) Unmount(id string) error {
+func (s *store) Unmount(id string, force bool) error {
 	if layerID, err := s.ContainerLayerID(id); err == nil {
 		id = layerID
 	}
@@ -2259,7 +2259,7 @@ func (s *store) Unmount(id string) error {
 		rlstore.Load()
 	}
 	if rlstore.Exists(id) {
-		return rlstore.Unmount(id)
+		return rlstore.Unmount(id, force)
 	}
 	return ErrLayerUnknown
 }
@@ -2811,7 +2811,7 @@ func (s *store) Shutdown(force bool) ([]string, error) {
 		mounted = append(mounted, layer.ID)
 		if force {
 			for layer.MountCount > 0 {
-				err2 := rlstore.Unmount(layer.ID)
+				err2 := rlstore.Unmount(layer.ID, force)
 				if err2 != nil {
 					if err == nil {
 						err = err2