snapshot: fix error on proxy driver when switching different snapshotter

Fixes: #592

Signed-off-by: ChengyuZhu6 <chengyu.zhu@intel.com>

snapshot/snapshot.go

@@ -318,7 +318,11 @@ func (o *snapshotter) Cleanup(ctx context.Context) error {
 }
 
 func (o *snapshotter) Stat(ctx context.Context, key string) (snapshots.Info, error) {
+	log.L.Debugf("[Stat] snapshots")
 	_, info, _, err := snapshot.GetSnapshotInfo(ctx, o.ms, key)
+	if checkErr := o.checkLabelsWithDriver(info.Labels); checkErr != nil {
+		return snapshots.Info{}, errors.New("not found")
+	}
 	return info, err
 }
 
@@ -1011,3 +1015,12 @@ func (o *snapshotter) snapshotRoot() string {
 func (o *snapshotter) snapshotDir(id string) string {
 	return filepath.Join(o.snapshotRoot(), id)
 }
+
+func (o *snapshotter) checkLabelsWithDriver(labels map[string]string) error {
+	isProxyDriver := config.GetFsDriver() == config.FsDriverProxy
+	isProxyLabel := label.IsNydusProxyMode(labels)
+	if (isProxyDriver && !isProxyLabel) || (!isProxyDriver && isProxyLabel) {
+		return errors.Errorf("check Labels With Driver failed, driver = %q, labels = %q", config.GetFsDriver(), labels)
+	}
+	return nil
+}