Update c/image after https://github.com/containers/image/pull/2408

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/github.com/containers/storage/store.go

@@ -2820,22 +2820,42 @@ func (s *store) mount(id string, options drivers.MountOpts) (string, error) {
 	}
 	defer s.stopUsingGraphDriver()
 
-	rlstore, err := s.getLayerStoreLocked()
+	rlstore, lstores, err := s.bothLayerStoreKindsLocked()
 	if err != nil {
 		return "", err
 	}
-	if err := rlstore.startWriting(); err != nil {
-		return "", err
-	}
-	defer rlstore.stopWriting()
-
 	if options.UidMaps != nil || options.GidMaps != nil {
 		options.DisableShifting = !s.canUseShifting(options.UidMaps, options.GidMaps)
 	}
 
-	if rlstore.Exists(id) {
-		return rlstore.Mount(id, options)
+	// function used to have a scope for rlstore.StopWriting()
+	tryMount := func() (string, error) {
+		if err := rlstore.startWriting(); err != nil {
+			return "", err
+		}
+		defer rlstore.stopWriting()
+		if rlstore.Exists(id) {
+			return rlstore.Mount(id, options)
+		}
+		return "", nil
 	}
+	mountPoint, err := tryMount()
+	if mountPoint != "" || err != nil {
+		return mountPoint, err
+	}
+
+	// check if the layer is in a read-only store, and return a better error message
+	for _, store := range lstores {
+		if err := store.startReading(); err != nil {
+			return "", err
+		}
+		exists := store.Exists(id)
+		store.stopReading()
+		if exists {
+			return "", fmt.Errorf("mounting read/only store images is not allowed: %w", ErrLayerUnknown)
+		}
+	}
+
 	return "", ErrLayerUnknown
 }