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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 3ADC9C48BD5 for ; Sun, 7 Jul 2019 05:28:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 09FC9208E4 for ; Sun, 7 Jul 2019 05:28:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QtdO50qv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725908AbfGGF1L (ORCPT ); Sun, 7 Jul 2019 01:27:11 -0400 Received: from mail-lf1-f47.google.com ([209.85.167.47]:33779 "EHLO mail-lf1-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725800AbfGGF1K (ORCPT ); Sun, 7 Jul 2019 01:27:10 -0400 Received: by mail-lf1-f47.google.com with SMTP id x3so2793123lfc.0 for ; Sat, 06 Jul 2019 22:27:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:openpgp:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4tfuzWM7/p7ssvUdvxGDc1SsWpcMDJF8VHNxlyWAjC8=; b=QtdO50qv1XjTihEe9Uu4iRzvcx8qXOve4VPxLZSMnBoLv/h64Ea6UBWWkaktKPHdKg jYyU2pbhJH3UeZRGnWpC3FWABuimnLxwx2mmZIEiY+0MuoaAL77Jfb3DgLO8BnLmzNHo qAkfC154vmcv/E6lvVnkUoQDGnKGaMaXCUjfvhiKpSRmRqTHpIA4pj61v9gNDWzBPmyO u6HDOhcRh93fjC1onrtdVqtLvMP26HQ2lBLn6S+/7fPyGXU6DrDuidMFRf7T9PquB7vq PyLdOWeNBIt5xEWD97quBTOx2mdE6SSCMWLpJFYeM051C8LEB1ouCumbwRa2n4q2ubE8 NuTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=4tfuzWM7/p7ssvUdvxGDc1SsWpcMDJF8VHNxlyWAjC8=; b=UOUolkVL55f279m4r2+/h/kOEyfmgGS4tIklVAsCOSyJwNCwjiWTyw+ltLuL78CNnC EQ4+1gXkN3XsYsUra/npa8pvVrtT3KWSnTwABS9oaH7psieZmmh8O3nnCMp1vFpfROlM 8DyxsUlrr98rJ9zQWo/4R0yWHFmr0O6NDWtiOfD6q5tV3XGRrbXrobJ+fkfICosRejmy mrxyiNsCbVDAemZt3qsDmANakSZ4oxNjWO+I5bbaoLAoXxdXW6JA5MdqQwRgEwoqJnyM ZkNLqWfVPuPh0JsnOICcoOis4SKa5RbzaO5Juokdtdj7QcGT8dled1JWF1aUl81S1NN9 pUNA== X-Gm-Message-State: APjAAAUMw6oGyB6B0pxPB60CA5fb1rN8qPa6rPy6Nyd85Gi/VDm02vEF aDvgdf3D/0meWrFzWp5mi2jo6LqO X-Google-Smtp-Source: APXvYqwN2D6uHQulBvxCnvgbZ6EMfZr3Hjs/qa+12dgW//CkmQ0/cWu3DMh06H3fNL4imLx2evsCrQ== X-Received: by 2002:ac2:43bb:: with SMTP id t27mr5597611lfl.187.1562477228396; Sat, 06 Jul 2019 22:27:08 -0700 (PDT) Received: from [192.168.1.6] (109-252-55-59.nat.spd-mgts.ru. [109.252.55.59]) by smtp.gmail.com with ESMTPSA id r68sm1262306lff.52.2019.07.06.22.27.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 06 Jul 2019 22:27:07 -0700 (PDT) Subject: Re: find snapshot parent? To: linux-btrfs@vger.kernel.org References: <20190706155353.GA13656@tik.uni-stuttgart.de> <1e70c50e-54d7-0507-60ad-9c486e3517a9@suse.com> <20190706204339.GB13656@tik.uni-stuttgart.de> From: Andrei Borzenkov Openpgp: preference=signencrypt Autocrypt: addr=arvidjaar@gmail.com; prefer-encrypt=mutual; keydata= xsDiBDxiRwwRBAC3CN9wdwpVEqUGmSoqF8tWVIT4P/bLCSZLkinSZ2drsblKpdG7x+guxwts +LgI8qjf/q5Lah1TwOqzDvjHYJ1wbBauxZ03nDzSLUhD4Ms1IsqlIwyTLumQs4vcQdvLxjFs G70aDglgUSBogtaIEsiYZXl4X0j3L9fVstuz4/wXtwCg1cN/yv/eBC0tkcM1nsJXQrC5Ay8D /1aA5qPticLBpmEBxqkf0EMHuzyrFlqVw1tUjZ+Ep2LMlem8malPvfdZKEZ71W1a/XbRn8FE SOp0tUa5GwdoDXgEp1CJUn+WLurR0KPDf01E4j/PHHAoABgrqcOTcIVoNpv2gNiBySVsNGzF XTeY/Yd6vQclkqjBYONGN3r9R8bWA/0Y1j4XK61qjowRk3Iy8sBggM3PmmNRUJYgroerpcAr 2byz6wTsb3U7OzUZ1Llgisk5Qum0RN77m3I37FXlIhCmSEY7KZVzGNW3blugLHcfw/HuCB7R 1w5qiLWKK6eCQHL+BZwiU8hX3dtTq9d7WhRW5nsVPEaPqudQfMSi/Ux1kc0mQW5kcmVpIEJv cnplbmtvdiA8YXJ2aWRqYWFyQGdtYWlsLmNvbT7CZQQTEQIAJQIbAwYLCQgHAwIGFQgCCQoL BBYCAwECHgECF4AFAliWAiQCGQEACgkQR6LMutpd94wFGwCeNuQnMDxve/Fo3EvYIkAOn+zE 21cAnRCQTXd1hTgcRHfpArEd/Rcb5+SczsBNBDxiRyQQBACQtME33UHfFOCApLki4kLFrIw1 5A5asua10jm5It+hxzI9jDR9/bNEKDTKSciHnM7aRUggLwTt+6CXkMy8an+tVqGL/MvDc4/R KKlZxj39xP7wVXdt8y1ciY4ZqqZf3tmmSN9DlLcZJIOT82DaJZuvr7UJ7rLzBFbAUh4yRKaN nwADBwQAjNvMr/KBcGsV/UvxZSm/mdpvUPtcw9qmbxCrqFQoB6TmoZ7F6wp/rL3TkQ5UElPR gsG12+Dk9GgRhnnxTHCFgN1qTiZNX4YIFpNrd0au3W/Xko79L0c4/49ten5OrFI/psx53fhY vLYfkJnc62h8hiNeM6kqYa/x0BEddu92ZG7CRgQYEQIABgUCPGJHJAAKCRBHosy62l33jMhd AJ48P7WDvKLQQ5MKnn2D/TI337uA/gCgn5mnvm4SBctbhaSBgckRmgSxfwQ= Message-ID: <8a75b6b5-1eba-b3ef-99f5-849f40e65d12@gmail.com> Date: Sun, 7 Jul 2019 08:27:06 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190706204339.GB13656@tik.uni-stuttgart.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 06.07.2019 23:43, Ulli Horlacher пишет: > On Sat 2019-07-06 (19:57), Nikolay Borisov wrote: > >>> And how can I see whether /test/tmp/xx/ss1 is a snapshot at all? >>> Do all snapshots have a "Parent UUID" and regular subvolumes not? >> >> Indeed, only snapshots have a Parent UUID. > > Not all: > > root@xerus:/test# btrfs subvolume snapshot -r /test /test/ss1 > Create a readonly snapshot of '/test' in '/test/ss1' > > root@xerus:/test# btrfs subvolume show /test/ss1 > /test/ss1 > Name: ss1 > UUID: 02bd07bc-0bab-3442-96be-40790e1ba9be > Parent UUID: - > Received UUID: - > Creation time: 2019-07-06 22:37:37 +0200 > Subvolume ID: 1036 > Generation: 9824 > Gen at creation: 9824 > Parent ID: 5 > Top level ID: 5 > Flags: readonly > Snapshot(s): > > root@xerus:/test# btrfs subvolume show /test > /test is toplevel subvolume > Which is one more reason to not use btrfs top level directly.