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,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 073DDC433ED for ; Wed, 28 Apr 2021 13:51:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CF07361447 for ; Wed, 28 Apr 2021 13:51:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238737AbhD1Nv4 (ORCPT ); Wed, 28 Apr 2021 09:51:56 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:59229 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S239013AbhD1Nvz (ORCPT ); Wed, 28 Apr 2021 09:51:55 -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 13SDourD012532 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Apr 2021 09:50:56 -0400 Received: by cwcc.thunk.org (Postfix, from userid 15806) id 3A78115C3C3D; Wed, 28 Apr 2021 09:50:56 -0400 (EDT) Date: Wed, 28 Apr 2021 09:50:56 -0400 From: "Theodore Ts'o" To: "Darrick J. Wong" Cc: Shreeya Patel , Matthew Wilcox , fstests@vger.kernel.org, linux-fsdevel@vger.kernel.org, krisman@collabora.com, preichl@redhat.com, kernel@collabora.com Subject: Re: [PATCH] generic/453: Exclude filenames that are not supported by exfat Message-ID: References: <20210425223105.1855098-1-shreeya.patel@collabora.com> <20210426003430.GH235567@casper.infradead.org> <20210426123734.GK235567@casper.infradead.org> <20210427181116.GH3122235@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210427181116.GH3122235@magnolia> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Apr 27, 2021 at 11:11:16AM -0700, Darrick J. Wong wrote: > > TBH I think these tests (g/453 and g/454) are probably only useful for > filesystems that allow unrestricted byte streams for names. I'm actually a little puzzled about why these tests should exist: # Create a directory with multiple filenames that all appear the same # (in unicode, anyway) but point to different inodes. In theory all # Linux filesystems should allow this (filenames are a sequence of # arbitrary bytes) even if the user implications are horrifying. Why do we care about testing this? The assertion "In all theory all Linux filesystems should allow this" is clearly not true --- if you enable unicode support for ext4 or f2fs, this will no longer be true, and this is considered by some a _feature_ not a bug --- precisely _because_ the user implications are horrifying. So why does these tests exist? Darrick, I see you added them in 2017 to test whether or not xfs_scrub will warn about confuable names, if _check_xfs_scrub_does_unicode is true. So we already understand that it's possible for a file system checker to complain that these file names are bad. It's not at all clear to me that asserting that all Linux file systems _must_ treat file names as "bag of bits" and not apply any kind of unicode normalization or strict unicode validation is a valid thing to test for in 2021. - Ted