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 E70EFC76186 for ; Wed, 17 Jul 2019 09:11:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC2BB2077C for ; Wed, 17 Jul 2019 09:11:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726081AbfGQJLE (ORCPT ); Wed, 17 Jul 2019 05:11:04 -0400 Received: from smtp02.belwue.de ([129.143.71.87]:61347 "EHLO smtp02.belwue.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725873AbfGQJLD (ORCPT ); Wed, 17 Jul 2019 05:11:03 -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 1A1FD8B02 for ; Wed, 17 Jul 2019 11:11:01 +0200 (MEST) Date: Wed, 17 Jul 2019 11:11:00 +0200 From: Ulli Horlacher To: linux-btrfs@vger.kernel.org Subject: Re: how do I know a subvolume is a snapshot? Message-ID: <20190717091100.GC3462@tik.uni-stuttgart.de> Mail-Followup-To: linux-btrfs@vger.kernel.org References: <20190716232456.GA26411@tik.uni-stuttgart.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 On Wed 2019-07-17 (11:24), Nikolay Borisov wrote: > > > On 17.07.19 3. 2:24 G., Ulli Horlacher wrote: > > > I thought, I can recognize a snapshot when it has a Parent UUID, but this > > is not true for snapshots of toplevel subvolumes: > > As you have asked this before - in my testing this is not true. It is true on all my SUSE and Ubuntu systems, for all versions. > Alternatively you have to parse the root tree - the ROOT_ITEM's offset > member should be 0 for well-known trees/ordinary subvolume or the > transaction id when the snapshot was created. Where can I find this ROOT_ITEM offset member? Which command? -- 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: