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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 D32C7C4361B for ; Sat, 19 Dec 2020 06:52:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5AC023A82 for ; Sat, 19 Dec 2020 06:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726398AbgLSGwX (ORCPT ); Sat, 19 Dec 2020 01:52:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbgLSGwX (ORCPT ); Sat, 19 Dec 2020 01:52:23 -0500 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9313CC06138C for ; Fri, 18 Dec 2020 22:51:42 -0800 (PST) Received: by mail-lf1-x131.google.com with SMTP id 23so11187248lfg.10 for ; Fri, 18 Dec 2020 22:51:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=wHh3AGKNUHGuxNBZIXl3F3lpRLpN0fkGHPtMG0h1E/Q=; b=CGZXxwnqvixvF/JfDlD/6y4awLzxnX9MxrDUFM3hXrsXQaw5M+mMG0ynofcfBP3gwh d2ky9udeH/1G33z7EVt6nLwx9r9xw2FzupLb08Zm8DZ9tlL1mjOKESN2jWUrMtZa4ee2 dX57uXD+3NDBfdgHtXmk2+8s/BLClQmfm1f/Vlh9AnwMdL18hDrRQf0dXa4kAz70N/9Q /lu1O6sH0AJfBe7m0lR/8AUelaqNzAZVuIgqZ5fd5OhPJGGE5eDi94H9V3QM93bo91ja cqpxhMV4Hlm4IENZoqc1a+5bQdtf7W/wWqw3E3CbU2CztG27XfESoTXUVPQzpZ72nBpR hGvw== 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:autocrypt:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=wHh3AGKNUHGuxNBZIXl3F3lpRLpN0fkGHPtMG0h1E/Q=; b=QSwPv0LNbZWIIOOyqPZeRhCna2ijTR9ilQsWwP03xSlJ7mfp4gWW35VPnVfZXzrGbD ZT9NwBB6K5smGaZE0EXiDUjByeVbIjNpgyBHqs5i9mS/M+jv1IF8OpNEaVTNA4uc9ne2 dBNd+doWMp4sOncTQSFel8uC8eQvv9xoph7c0XTUDSysy1NMGsVNLLRQoShR3Jw3Njeb Gf1UY2XZCJ6bbtKURNgeo4i5s7Sx7xnWCmTDVPMjP16mEhSFXpjtGlYOA3te7Akw4tTC q9fPkl3E5QAh/QGotYxx3+Jkr2AlOH59cUy8X4boePRIC8BCn81BQyEPw7kq2mdFQ7nY 2HuQ== X-Gm-Message-State: AOAM531zVGrA+9VISyaBfPSKWg1/FP0p6vzxbr0dN/sKxYNbdl5ThP1h y4byABOpUQGGNNt1/fsCJSrinKrxrs8= X-Google-Smtp-Source: ABdhPJzHnoFEU70eQVJ7GWOsq9ZY21psPQOT8+EGCMRlJYPic7k453F+aGeuDWh6HuaQnjEF4GARQw== X-Received: by 2002:a05:651c:130b:: with SMTP id u11mr3067579lja.118.1608360701014; Fri, 18 Dec 2020 22:51:41 -0800 (PST) Received: from ?IPv6:2a00:1370:812d:ecb3:590f:aaab:50ba:573b? ([2a00:1370:812d:ecb3:590f:aaab:50ba:573b]) by smtp.gmail.com with ESMTPSA id e9sm1187340lfc.253.2020.12.18.22.51.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Dec 2020 22:51:40 -0800 (PST) Subject: Re: what determines what /dev/ is mounted? To: Chris Murphy , Btrfs BTRFS References: From: Andrei Borzenkov Autocrypt: addr=arvidjaar@gmail.com; prefer-encrypt=mutual; keydata= mQGiBDxiRwwRBAC3CN9wdwpVEqUGmSoqF8tWVIT4P/bLCSZLkinSZ2drsblKpdG7x+guxwts +LgI8qjf/q5Lah1TwOqzDvjHYJ1wbBauxZ03nDzSLUhD4Ms1IsqlIwyTLumQs4vcQdvLxjFs G70aDglgUSBogtaIEsiYZXl4X0j3L9fVstuz4/wXtwCg1cN/yv/eBC0tkcM1nsJXQrC5Ay8D /1aA5qPticLBpmEBxqkf0EMHuzyrFlqVw1tUjZ+Ep2LMlem8malPvfdZKEZ71W1a/XbRn8FE SOp0tUa5GwdoDXgEp1CJUn+WLurR0KPDf01E4j/PHHAoABgrqcOTcIVoNpv2gNiBySVsNGzF XTeY/Yd6vQclkqjBYONGN3r9R8bWA/0Y1j4XK61qjowRk3Iy8sBggM3PmmNRUJYgroerpcAr 2byz6wTsb3U7OzUZ1Llgisk5Qum0RN77m3I37FXlIhCmSEY7KZVzGNW3blugLHcfw/HuCB7R 1w5qiLWKK6eCQHL+BZwiU8hX3dtTq9d7WhRW5nsVPEaPqudQfMSi/Ux1kbQmQW5kcmV5IEJv cnplbmtvdiA8YXJ2aWRqYWFyQGdtYWlsLmNvbT6IYAQTEQIAIAUCSXs6NQIbAwYLCQgHAwIE FQIIAwQWAgMBAh4BAheAAAoJEEeizLraXfeMLOYAnj4ovpka+mXNzImeYCd5LqW5to8FAJ4v P4IW+Ic7eYXxCLM7/zm9YMUVbrQmQW5kcmVpIEJvcnplbmtvdiA8YXJ2aWRqYWFyQGdtYWls LmNvbT6IZQQTEQIAJQIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AFAliWAiQCGQEACgkQ R6LMutpd94wFGwCeNuQnMDxve/Fo3EvYIkAOn+zE21cAnRCQTXd1hTgcRHfpArEd/Rcb5+Sc uQENBDxiRyQQBACQtME33UHfFOCApLki4kLFrIw15A5asua10jm5It+hxzI9jDR9/bNEKDTK SciHnM7aRUggLwTt+6CXkMy8an+tVqGL/MvDc4/RKKlZxj39xP7wVXdt8y1ciY4ZqqZf3tmm SN9DlLcZJIOT82DaJZuvr7UJ7rLzBFbAUh4yRKaNnwADBwQAjNvMr/KBcGsV/UvxZSm/mdpv UPtcw9qmbxCrqFQoB6TmoZ7F6wp/rL3TkQ5UElPRgsG12+Dk9GgRhnnxTHCFgN1qTiZNX4YI FpNrd0au3W/Xko79L0c4/49ten5OrFI/psx53fhYvLYfkJnc62h8hiNeM6kqYa/x0BEddu92 ZG6IRgQYEQIABgUCPGJHJAAKCRBHosy62l33jMhdAJ48P7WDvKLQQ5MKnn2D/TI337uA/gCg n5mnvm4SBctbhaSBgckRmgSxfwQ= Message-ID: Date: Sat, 19 Dec 2020 09:51:39 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 19.12.2020 00:42, Chris Murphy пишет: > When I have a 2-device btrfs: > > devid 1 = /dev/vdb1 > devid 2 = /dev/vdc1 > > Regardless of the mount command, df and /proc/mounts shows /dev/vdb1 is mounted. > > If I flip the backing assignments in qemu, such that: > > devid 2 = /dev/vdb1 > devid 1 = /dev/vdc1 > > Now, /dev/vdc1 is shown as mounted by df and /proc/mounts. > > But this isn't scientific. Is there a predictable logic? Is it always > the lowest devid? > It is the lowest devid which is present (ignoring "missing" devices).