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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 1432CC4361B for ; Fri, 18 Dec 2020 21:44:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DAFAF23B54 for ; Fri, 18 Dec 2020 21:44:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726235AbgLRVns (ORCPT ); Fri, 18 Dec 2020 16:43:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725822AbgLRVns (ORCPT ); Fri, 18 Dec 2020 16:43:48 -0500 Received: from mail-wr1-x429.google.com (mail-wr1-x429.google.com [IPv6:2a00:1450:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8340C0617A7 for ; Fri, 18 Dec 2020 13:43:07 -0800 (PST) Received: by mail-wr1-x429.google.com with SMTP id d26so3795725wrb.12 for ; Fri, 18 Dec 2020 13:43:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=colorremedies-com.20150623.gappssmtp.com; s=20150623; h=mime-version:from:date:message-id:subject:to; bh=BVrnFOBNITYCKeO+wqy8Hskrwvb905EF38c/ZDeiUw8=; b=2EG5xq487GYrhsL3YlMH1Yd/2+Cc0WOUgjtSJWbPQPwsApakQXOHrXqcrcGQTPDOBI al4YjEWnxT+MGbGLnanYDEOgGP4VNdbAC2ji93Q3HKUcYkyMpdJ2Mq31oTDEuD/4pCNq zKadZ89R+4Ck9bm4+jEKxd9cRWiTe9aXa09daPNtCsWC5LnmAr5Py7+ViDjAy+h43r22 b0Y7wAMgFyV+ylahDJbJpjvO3uL6rZD4kfDotjvjvpJtfN32T4aIN1Jn8isCYHuX4Zt0 JSWD6/Ak/vgwKivC1zE3ztUQ5RdNi/jM9Rf0twXwp7V4rovDn5n7xftUIAQuO2aZFHtQ IhUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=BVrnFOBNITYCKeO+wqy8Hskrwvb905EF38c/ZDeiUw8=; b=JrkOCHGn2NunkHcoFtt4qc+hX8R7TMReWje1tWfXDUMmptgegFYnF2dTbwJRGEz6Kk 9v1cwJLmNv3jA479V09E7yzWEtJr0OBdc0axFK3smz6TVPxQiz9Z8j6YD1C7R1ufqxoN Ld4ZNRoV3lYZx40w6NOPAeSkiL+qZWsrMuYhu0b7OIgUTNrw6FeKkKF2Gq5OKXKKIGa+ Nm3+lN6d5K1kRjvN8j+j7wGneCkZF1EJ6/+eaiJeOXlb8GhdkEvlOY3CTYnBoTCfAam8 DypGCv9YiiPphyiluXSSbTP63jqZe5MzAuYXIOrB3tj60CnSuaoj3K69b9PeFgi94g+h 0wvA== X-Gm-Message-State: AOAM530Kq57bODyYH83dKmVJIe2TkgeV0uqP+jOeZwOEGHth/Ad+ZmR+ 6EIN2YNv1k8j65V3FZng1rp9Fk0Y5hpKn5594YtWTnd8BEr0iajW X-Google-Smtp-Source: ABdhPJzHzcXlaYNkGPakGHZzxZN+dKOTaFURjErLkpDOgPfvP2if9zULBf0tRhg4aiuETDwQC+JPVHJC2NLU2mlPMaw= X-Received: by 2002:adf:e2ca:: with SMTP id d10mr6534600wrj.65.1608327786366; Fri, 18 Dec 2020 13:43:06 -0800 (PST) MIME-Version: 1.0 From: Chris Murphy Date: Fri, 18 Dec 2020 14:42:50 -0700 Message-ID: Subject: what determines what /dev/ is mounted? To: Btrfs BTRFS Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 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? -- Chris Murphy