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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY 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 E3D79C433ED for ; Thu, 29 Apr 2021 14:32:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F7B76144B for ; Thu, 29 Apr 2021 14:32:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236096AbhD2OdR (ORCPT ); Thu, 29 Apr 2021 10:33:17 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:35550 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237338AbhD2OdO (ORCPT ); Thu, 29 Apr 2021 10:33:14 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 395D01F432F8 From: Gabriel Krisman Bertazi To: "Darrick J. Wong" Cc: Theodore Ts'o , Shreeya Patel , Matthew Wilcox , fstests@vger.kernel.org, linux-fsdevel@vger.kernel.org, preichl@redhat.com, kernel@collabora.com Subject: Re: [PATCH] generic/453: Exclude filenames that are not supported by exfat Organization: Collabora References: <20210425223105.1855098-1-shreeya.patel@collabora.com> <20210426003430.GH235567@casper.infradead.org> <20210426123734.GK235567@casper.infradead.org> <20210427181116.GH3122235@magnolia> <20210429003726.GG1251862@magnolia> Date: Thu, 29 Apr 2021 10:32:23 -0400 In-Reply-To: <20210429003726.GG1251862@magnolia> (Darrick J. Wong's message of "Wed, 28 Apr 2021 17:37:26 -0700") Message-ID: <87eeet6u14.fsf@collabora.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org "Darrick J. Wong" writes: > On Wed, Apr 28, 2021 at 09:50:56AM -0400, Theodore Ts'o wrote: >> 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. > > Yes, that's exactly why this test (and generic/454) were created -- as a > functional test for xfs_scrub's unicode checking. > >> 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. > > Perhaps not. These two tests do have the interesting side effect of > catching filesystems that don't hew to the "names are bytestreams" > philosophy. In 2017, fstests usage seemed like it pretty narrowly > included only the big three filesystems, so it amuses me to no end that > four years went by before this discussion started. :P > > Nowadays with wider testing of other filesystems (thanks, Red Hat!) we > should hide these behind _require_names_are_bytes or move them to > tests/xfs/. > > Question -- the unicode case folding doesn't apply to xattr names, > right? No, they don't apply to xattr name in ext4 and f2fs. -- Gabriel Krisman Bertazi