From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7252C7618F for ; Tue, 16 Jul 2019 23:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79AFB2173E for ; Tue, 16 Jul 2019 23:25:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728986AbfGPXZC (ORCPT ); Tue, 16 Jul 2019 19:25:02 -0400 Received: from smtp02.belwue.de ([129.143.71.87]:58046 "EHLO smtp02.belwue.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728414AbfGPXZC (ORCPT ); Tue, 16 Jul 2019 19:25:02 -0400 Received: from fex.rus.uni-stuttgart.de (fex.rus.uni-stuttgart.de [129.69.1.129]) by smtp02.belwue.de (Postfix) with SMTP id 462348D4C for ; Wed, 17 Jul 2019 01:24:56 +0200 (MEST) Date: Wed, 17 Jul 2019 01:24:56 +0200 From: Ulli Horlacher To: linux-btrfs@vger.kernel.org Subject: how do I know a subvolume is a snapshot? Message-ID: <20190716232456.GA26411@tik.uni-stuttgart.de> Mail-Followup-To: linux-btrfs@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org I thought, I can recognize a snapshot when it has a Parent UUID, but this is not true for snapshots of toplevel subvolumes: root@trulla:/# btrfs version btrfs-progs v4.5.3+20160729 root@trulla:/# btrfs subvolume show /mnt/tmp /mnt/tmp is toplevel subvolume root@trulla:/# btrfs subvolume snapshot /mnt/tmp /mnt/tmp/ss Create a snapshot of '/mnt/tmp' in '/mnt/tmp/ss' root@trulla:/# btrfs subvolume create /mnt/tmp/xx Create subvolume '/mnt/tmp/xx' root@trulla:/# btrfs subvolume show /mnt/tmp/ss /mnt/tmp/ss Name: ss UUID: 7732bdde-0485-204e-b41b-833376e791da Parent UUID: - Received UUID: - Creation time: 2019-07-17 01:02:48 +0200 Subvolume ID: 270 Generation: 60 Gen at creation: 60 Parent ID: 5 Top level ID: 5 Flags: - Snapshot(s): root@trulla:/# btrfs subvolume show /mnt/tmp/xx /mnt/tmp/xx Name: xx UUID: 342b2065-1679-8245-bd76-8da598cc33d8 Parent UUID: - Received UUID: - Creation time: 2019-07-17 01:03:02 +0200 Subvolume ID: 271 Generation: 61 Gen at creation: 61 Parent ID: 5 Top level ID: 5 Flags: - Snapshot(s): How do I know that /mnt/tmp/ss is a snapshot? I cannot see a snapshot identifier. -- Ullrich Horlacher Server und Virtualisierung Rechenzentrum TIK Universitaet Stuttgart E-Mail: horlacher@tik.uni-stuttgart.de Allmandring 30a Tel: ++49-711-68565868 70569 Stuttgart (Germany) WWW: http://www.tik.uni-stuttgart.de/ REF:<20190716232456.GA26411@tik.uni-stuttgart.de>