Fix tx closed error when upperdirlabel specified

When upperdirLabel specified, overlay Update will throw tx closed error since Commit is invoked before GetInfo

Signed-off-by: cardy.tang <zuniorone@gmail.com>
(cherry picked from commit 9f9ebbd)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

snapshots/overlay/overlay.go

@@ -160,10 +160,6 @@ func (o *snapshotter) Update(ctx context.Context, info snapshots.Info, fieldpath
 		return snapshots.Info{}, err
 	}
 
-	if err := t.Commit(); err != nil {
-		return snapshots.Info{}, err
-	}
-
 	if o.upperdirLabel {
 		id, _, _, err := storage.GetInfo(ctx, info.Name)
 		if err != nil {
@@ -175,6 +171,10 @@ func (o *snapshotter) Update(ctx context.Context, info snapshots.Info, fieldpath
 		info.Labels[upperdirKey] = o.upperPath(id)
 	}
 
+	if err := t.Commit(); err != nil {
+		return snapshots.Info{}, err
+	}
+
 	return info, nil
 }