Merge pull request #3088 from fuweid/me-cp-2876-release-1.1

[release/1.1 backporting] bugfix: unpack should always set the snapshot gc label

image.go

@@ -153,26 +153,22 @@ func (i *image) Unpack(ctx context.Context, snapshotterName string) error {
 		chain = append(chain, layer.Diff.Digest)
 	}
 
-	if unpacked {
-		desc, err := i.i.Config(ctx, cs, platforms.Default())
-		if err != nil {
-			return err
-		}
+	desc, err := i.i.Config(ctx, cs, platforms.Default())
+	if err != nil {
+		return err
+	}
 
-		rootfs := identity.ChainID(chain).String()
+	rootfs := identity.ChainID(chain).String()
 
-		cinfo := content.Info{
-			Digest: desc.Digest,
-			Labels: map[string]string{
-				fmt.Sprintf("containerd.io/gc.ref.snapshot.%s", snapshotterName): rootfs,
-			},
-		}
-		if _, err := cs.Update(ctx, cinfo, fmt.Sprintf("labels.containerd.io/gc.ref.snapshot.%s", snapshotterName)); err != nil {
-			return err
-		}
+	cinfo := content.Info{
+		Digest: desc.Digest,
+		Labels: map[string]string{
+			fmt.Sprintf("containerd.io/gc.ref.snapshot.%s", snapshotterName): rootfs,
+		},
 	}
 
-	return nil
+	_, err = cs.Update(ctx, cinfo, fmt.Sprintf("labels.containerd.io/gc.ref.snapshot.%s", snapshotterName))
+	return err
 }
 
 func (i *image) getLayers(ctx context.Context, platform string) ([]rootfs.Layer, error) {