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 52D78C76186 for ; Wed, 17 Jul 2019 08:06:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C9C12077C for ; Wed, 17 Jul 2019 08:06:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726115AbfGQIGB (ORCPT ); Wed, 17 Jul 2019 04:06:01 -0400 Received: from smtp02.belwue.de ([129.143.71.87]:50626 "EHLO smtp02.belwue.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725890AbfGQIGA (ORCPT ); Wed, 17 Jul 2019 04:06:00 -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 D7E8A8F4B for ; Wed, 17 Jul 2019 10:05:57 +0200 (MEST) Date: Wed, 17 Jul 2019 10:05:57 +0200 From: Ulli Horlacher To: linux-btrfs@vger.kernel.org Subject: Re: how do I know a subvolume is a snapshot? Message-ID: <20190717080557.GA3462@tik.uni-stuttgart.de> Mail-Followup-To: linux-btrfs@vger.kernel.org References: <20190716232456.GA26411@tik.uni-stuttgart.de> <1858db2d-8683-0ba9-cc13-9e654a1fa810@allchangeplease.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1858db2d-8683-0ba9-cc13-9e654a1fa810@allchangeplease.de> 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 (09:45), Bernhard Kühnel wrote: > Am 17.07.2019 um 01:24 schrieb Ulli Horlacher: > > > How do I know that /mnt/tmp/ss is a snapshot? > > I cannot see a snapshot identifier. > > From the btrfs-subvolume man page: > > >       A snapshot is a subvolume like any other, with given initial content. By default, snapshots are created > >       read-write. File modifications in a snapshot do not affect the files in the original subvolume. I know this, but my question was not "What is a snapshot". > I believe the usual practice is to create snapshots with the -r flag and > follow some naming convention (e.g. place them in a common .snapshots > folder named by date), but you're free to switch between read-only and > read-write mode for a snapshot at any time using the btrfs property command. This is true also for my users and co-admins. Though, I want to know which subvolume is a snapshot of what subvolume. Non-toplevel subvolume snapshots have a Parent UUID - why not all?! Or at least some kind of flag "I am a snapshot". -- 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:<1858db2d-8683-0ba9-cc13-9e654a1fa810@allchangeplease.de>