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, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE 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 3A053C43619 for ; Thu, 15 Apr 2021 15:01:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A640613D3 for ; Thu, 15 Apr 2021 15:01:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234303AbhDOPB3 (ORCPT ); Thu, 15 Apr 2021 11:01:29 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:53899 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S234884AbhDOPAG (ORCPT ); Thu, 15 Apr 2021 11:00:06 -0400 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 13FExS1V031149 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 Apr 2021 10:59:29 -0400 Received: by cwcc.thunk.org (Postfix, from userid 15806) id 547EE15C3B35; Thu, 15 Apr 2021 10:59:28 -0400 (EDT) Date: Thu, 15 Apr 2021 10:59:28 -0400 From: "Theodore Ts'o" To: Christian Brauner Cc: Christoph Hellwig , Eryu Guan , Christian Brauner , fstests@vger.kernel.org, linux-ext4@vger.kernel.org, "Darrick J . Wong" , David Howells , Amir Goldstein Subject: Re: [PATCH -RFC] ext4: add feature file to advertise that ext4 supports idmapped mounts Message-ID: References: <20210411151249.6y34x7yatqtpcvi6@wittgenstein> <20210411151857.wd6gd46u53vlh2xv@wittgenstein> <20210411153223.vhcegiklrwoczy55@wittgenstein> <20210412115426.a4bzsx4cp7jhx2ou@wittgenstein> <20210415055408.GA8947@lst.de> <20210415074921.cf5uv4xehlctvtvv@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210415074921.cf5uv4xehlctvtvv@wittgenstein> Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org On Thu, Apr 15, 2021 at 09:49:21AM +0200, Christian Brauner wrote: > Harsh words. :) > Christoph's right though I think for the xfstests we don't need it and > we're covered with what we have in the version I sent out last Sunday. Sorry, I had missed your v13 patch set and that it had included tests for the existence of idmapped. I had sent out the RFC patch because I was under the impression that we hadn't made forward progress on testing for the support idmapped mounts. If we have a way of doing this, and you're comfortable that it is reliable (e.g., that a bug might cause the test to be skipped because it thinks the file system doesn't support idmapped mount, when really it was caused by a regression), and I'm happy to just rely on the method you've used in the v13 fstests patch set. That being said, I still think it would be helpful to have a VFS-standard way for userspace to be able to test for the presence of a particular kernel feature/capability without having to do a test mount, possibly requiring setting up a test user_ns, etc., etc. But that isn't as urgent as making sure we can easily the feature without needing manual customization of the test suite as file systems add support for the feature, or as the feature gets backported to enterprise distro kernels. Cheers, - Ted