From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-security-module-owner@kernel.org>
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=-5.2 required=3.0 tests=BAYES_00,
	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 583FBC83011
	for <linux-security-module@archiver.kernel.org>; Tue,  1 Dec 2020 11:14:27 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id F37F220809
	for <linux-security-module@archiver.kernel.org>; Tue,  1 Dec 2020 11:14:26 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S2388974AbgLALOK (ORCPT
        <rfc822;linux-security-module@archiver.kernel.org>);
        Tue, 1 Dec 2020 06:14:10 -0500
Received: from verein.lst.de ([213.95.11.211]:49229 "EHLO verein.lst.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1727463AbgLALOJ (ORCPT
        <rfc822;linux-security-module@vger.kernel.org>);
        Tue, 1 Dec 2020 06:14:09 -0500
Received: by verein.lst.de (Postfix, from userid 2407)
        id 2681867373; Tue,  1 Dec 2020 12:13:21 +0100 (CET)
Date:   Tue, 1 Dec 2020 12:13:20 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Christian Brauner <christian.brauner@ubuntu.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        linux-fsdevel@vger.kernel.org,
        John Johansen <john.johansen@canonical.com>,
        James Morris <jmorris@namei.org>,
        Mimi Zohar <zohar@linux.ibm.com>,
        Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
        Geoffrey Thomas <geofft@ldpreload.com>,
        Mrunal Patel <mpatel@redhat.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Andy Lutomirski <luto@kernel.org>,
        Theodore Tso <tytso@mit.edu>, Alban Crequy <alban@kinvolk.io>,
        Tycho Andersen <tycho@tycho.ws>,
        David Howells <dhowells@redhat.com>,
        James Bottomley <James.Bottomley@hansenpartnership.com>,
        Seth Forshee <seth.forshee@canonical.com>,
        =?iso-8859-1?Q?St=E9phane?= Graber <stgraber@ubuntu.com>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Lennart Poettering <lennart@poettering.net>,
        "Eric W. Biederman" <ebiederm@xmission.com>, smbarber@chromium.org,
        Phil Estes <estesp@gmail.com>, Serge Hallyn <serge@hallyn.com>,
        Kees Cook <keescook@chromium.org>,
        Todd Kjos <tkjos@google.com>, Paul Moore <paul@paul-moore.com>,
        Jonathan Corbet <corbet@lwn.net>,
        containers@lists.linux-foundation.org, fstests@vger.kernel.org,
        linux-security-module@vger.kernel.org, linux-api@vger.kernel.org,
        linux-ext4@vger.kernel.org, linux-integrity@vger.kernel.org,
        selinux@vger.kernel.org
Subject: Re: [PATCH v3 33/38] ext4: support idmapped mounts
Message-ID: <20201201111320.GA31288@lst.de>
References: <20201128213527.2669807-1-christian.brauner@ubuntu.com> <20201128213527.2669807-34-christian.brauner@ubuntu.com> <20201201105445.GJ27730@lst.de> <20201201110219.7gykwbsij6ld45wb@wittgenstein>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20201201110219.7gykwbsij6ld45wb@wittgenstein>
User-Agent: Mutt/1.5.17 (2007-11-01)
Precedence: bulk
List-ID: <linux-security-module.vger.kernel.org>

On Tue, Dec 01, 2020 at 12:02:19PM +0100, Christian Brauner wrote:
> On Tue, Dec 01, 2020 at 11:54:45AM +0100, Christoph Hellwig wrote:
> > What is the reason for the config option?  The only thing that it
> > controls is setting of a single flag.
> 
> I wanted to be conservative and give users the option to disable this on
> their kernel. Would you prefer if I drop it?

I don't think adding an option per file system scales in any way.  If
there is some strong urge to disable the functionality (which I see no
reason for) we could add something like a global sysctl for all on-disk
file systems.