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=-0.8 required=3.0 tests=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 A1040C31E40 for ; Mon, 12 Aug 2019 14:11:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E7B7208C2 for ; Mon, 12 Aug 2019 14:11:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727764AbfHLOL4 (ORCPT ); Mon, 12 Aug 2019 10:11:56 -0400 Received: from mail-qk1-f193.google.com ([209.85.222.193]:39728 "EHLO mail-qk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727206AbfHLOLz (ORCPT ); Mon, 12 Aug 2019 10:11:55 -0400 Received: by mail-qk1-f193.google.com with SMTP id 125so3974702qkl.6; Mon, 12 Aug 2019 07:11:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HckXkSELBT5jyRopE2pzV3JrBcZaAIu4qF7LSK+P/Zk=; b=Le6/ABehm9ETT3puLLGQvgwqe8JavRVTGi/pbQF7plDOxMcDXm16SYrE6mLxav5ZBO dMvA8Vdd5jBWf2FyP+ttnWFWtHZ84WDUP4gW6R8Fvg6ee2VWueZG5Jiqv/FEHeypiMzW bcDWHxIQGEgrYCp2ZG4oJUBNQe5jF331dQO+c9qj8gMnUgOm7YgF6t6mDbM6UjmnECc/ S7xBP6aud+w4DBN2DTYBotlDbOPNHMTVF62bnI7M7TB4kSVvyKgjraTDT7QPBT4Np8H/ HWK/Hxwj4T46cvmXeOzLxNOIPrN+ED9B3mV8FpyDZpDv27y6ILvL0GSu3UZrtCYcVGJT 18TA== X-Gm-Message-State: APjAAAWJ4P2+Zx2olBZ4OuAmDBhjbXOXANAnHSBw5zjV0bJFZ4JToosX G+IESdP4CTuQFjzrMiW4A86Y42uzKNebkl6e5wM= X-Google-Smtp-Source: APXvYqxtt7OhOLMOBKJ7ckgLW8+yi7AHTbnlSXtQb5z7c1RrTlQlkHiOx9q+BjSXgB4EEwuNQuPQFcogoxaDzLeahwc= X-Received: by 2002:a05:620a:b:: with SMTP id j11mr30315011qki.352.1565619114553; Mon, 12 Aug 2019 07:11:54 -0700 (PDT) MIME-Version: 1.0 References: <20190730014924.2193-1-deepa.kernel@gmail.com> <20190730014924.2193-5-deepa.kernel@gmail.com> <53df9d81bfb4ee7ec64fabf1089f91d80dceb491.camel@codethink.co.uk> In-Reply-To: <53df9d81bfb4ee7ec64fabf1089f91d80dceb491.camel@codethink.co.uk> From: Arnd Bergmann Date: Mon, 12 Aug 2019 16:11:38 +0200 Message-ID: Subject: Re: [Y2038] [PATCH 04/20] mount: Add mount warning for impending timestamp expiry To: Ben Hutchings Cc: Deepa Dinamani , Alexander Viro , Linux Kernel Mailing List , Linux FS-devel Mailing List , y2038 Mailman List Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Aug 12, 2019 at 3:25 PM Ben Hutchings wrote: > On Sat, 2019-08-10 at 13:44 -0700, Deepa Dinamani wrote: > > On Mon, Aug 5, 2019 at 7:14 AM Ben Hutchings > > wrote: > > > On Mon, 2019-07-29 at 18:49 -0700, Deepa Dinamani wrote: > > > > The warning reuses the uptime max of 30 years used by the > > > > setitimeofday(). > > > > > > > > Note that the warning is only added for new filesystem mounts > > > > through the mount syscall. Automounts do not have the same warning. > > > [...] > > > > > > Another thing - perhaps this warning should be suppressed for read-only > > > mounts? > > > > Many filesystems support read only mounts only. We do fill in right > > granularities and limits for these filesystems as well. In keeping > > with the trend, I have added the warning accordingly. I don't think I > > have a preference either way. But, not warning for the red only mounts > > adds another if case. If you have a strong preference, I could add it > > in. > > It seems to me that the warning is needed if there is a possibility of > data loss (incorrect timestamps, potentially leading to incorrect > decisions about which files are newer). This can happen only when a > filesystem is mounted read-write, or when a filesystem image is > created. > > I think that warning for read-only mounts would be an annoyance to > users retrieving files from old filesystems. I agree, the warning is not helpful for read-only mounts. An earlier plan was to completely disallow writable mounts that might risk an overflow (in some configurations at least). The warning replaces that now, and I think it should also just warn for the cases that would otherwise have been dangerous. Arnd