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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53885C76188 for ; Wed, 5 Apr 2023 06:13:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236979AbjDEGNF (ORCPT ); Wed, 5 Apr 2023 02:13:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237023AbjDEGNA (ORCPT ); Wed, 5 Apr 2023 02:13:00 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBC9C120 for ; Tue, 4 Apr 2023 23:12:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=SYzGzXKN8+b2GwuirxBSKVa3AMhD9/wkNdxjust90pM=; b=pY6HWDckmw7unwEt3deEl7v8PY BSxpjPtLpbEQthrL8zmDEl8cJn0rGqW033U4x+8z7kSEtIjLnM5whVEWcN5yq5i2pIi350V8HQgDj tk3++XvBYlN/j/8t6UPUZsEgWFaBjwpVtmOXh1bLljFQG6Pek9zuYmPA4srOf0QdEGqxxRj5obSs4 vIMMOOxWp7KSjskgSMKhzfDjRI/R5DceESWF/jk5fa1QXXWjh+ANXYzOBcOgGX7JNytv+C2OEC7yj U3E6HY/DaADvSIlipXcbkz9uDACmA5Qt++Dpt8uyOxbgxz8QoUo5z7dy7MaRU8OI0dDg+XEcnyqTg 8AiGiXPw==; Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1pjwO8-003Tsw-2g; Wed, 05 Apr 2023 06:12:56 +0000 Date: Tue, 4 Apr 2023 23:12:56 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Linus Torvalds , linux-xfs@vger.kernel.org, david@fromorbit.com Subject: Re: [PATCH 1/3] xfs: stabilize the tolower function used for ascii-ci dir hash computation Message-ID: References: <168062802052.174368.10967543545284986225.stgit@frogsfrogsfrogs> <168062802637.174368.12108206682992075671.stgit@frogsfrogsfrogs> <20230404183214.GG109974@frogsfrogsfrogs> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230404183214.GG109974@frogsfrogsfrogs> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Apr 04, 2023 at 11:32:14AM -0700, Darrick J. Wong wrote: > Yeah, I get that. Fifteen years ago, Barry Naujok and Christoph merged > this weird ascii-ci feature for XFS that purportedly does ... something. > It clearly only works properly if you force userspace to use latin1, > which is totally nuts in 2023 given that the distros default to UTF8 > and likely don't test anything else. It probably wasn't even a good > idea in *2008*, but it went in anyway. Nobody tested this feature, > metadump breaks with this feature enabled, but as maintainer I get to > maintain these poorly designed half baked projects. IIRC the idea was that it should do 7-bit ASCII only, so even accepting Latin 1 characters seems like a bug compared to what it was documented to do. > I wouldn't ever enable this feature on any computer I use, and I think > the unicode case-insensitive stuff that's been put in to ext4 and f2fs > lately are not a tarpit that I ever want to visit in XFS. Directory > names should be sequences of bytes that don't include nulls or slashes, > end of story. That works fine if all you care is classic Linux / Unix users. And while I'd prefer if all the world was like that, the utf8 based CI has real use cases. Initially mostly for Samba file serving, but apparently Wine also really benefits from it, so some people have CI directories for that. XFS ignoring this means we are missing out on those usrers. The irony is all the utf8 infrastruture was developed for XFS use by SGI, never made it upstream back then and got picked up for ext4. And while it is objectively horrible, plugging into this actually working infrastructure would be the right thing for XFS instead of the whacky ASCII only mode only done as a stepping stone while the utf8 infrastructure got finished.