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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 AA8EAC4320E for ; Thu, 19 Aug 2021 19:55:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5A943610F9 for ; Thu, 19 Aug 2021 19:55:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5A943610F9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 01BA36B006C; Thu, 19 Aug 2021 15:55:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F0E7F6B0071; Thu, 19 Aug 2021 15:55:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DFD1B6B0072; Thu, 19 Aug 2021 15:55:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0242.hostedemail.com [216.40.44.242]) by kanga.kvack.org (Postfix) with ESMTP id C78096B006C for ; Thu, 19 Aug 2021 15:55:12 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 764CB80A0751 for ; Thu, 19 Aug 2021 19:55:12 +0000 (UTC) X-FDA: 78492884064.36.C9D4F69 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf14.hostedemail.com (Postfix) with ESMTP id 1A2056001986 for ; Thu, 19 Aug 2021 19:55:11 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 71009610A5; Thu, 19 Aug 2021 19:55:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629402911; bh=a7hA2i1JEu2oNE3vKMxIBbK/e83UydJxEWPDh43mTdQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=d3CMeAe9SK80ZY+a4MOWda/Fzm7Lfq0N6tpDOQ1W5hDmmhy2reBm34QrnQERUxJul G9sn5DE0WvICokk4lAbvyR49dzprb1tLXbgIhoH5y971HD9nOraJGCjdViLUgrlj69 xCtoQhhp32pkD3/CmK/DFFnvx1yveF/Kid9C0jkVqDKc89DF+J5GviG2L8HcD/3tQP i/iIH7pjAOy/I/r/PQ742Asin6ojMCpwfg9OVnJ8Fq0rzmGnN2lUFtg1Osau5wBr3w KsvJAEvNOyMWi1gs+8nhqECbO+wdtwingfK/846hL5TUxVerK9wWFKAgMGNZUNxasE V2Hg7ToCX2MqQ== Date: Thu, 19 Aug 2021 12:55:08 -0700 From: Eric Biggers To: Linus Torvalds Cc: Jeff Layton , "Eric W. Biederman" , Matthew Wilcox , Andy Lutomirski , David Laight , David Hildenbrand , Linux Kernel Mailing List , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Al Viro , Alexey Dobriyan , Steven Rostedt , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Kees Cook , Greg Ungerer , Geert Uytterhoeven , Mike Rapoport , Vlastimil Babka , Vincenzo Frascino , Chinwen Chang , Michel Lespinasse , Catalin Marinas , Huang Ying , Jann Horn , Feng Tang , Kevin Brodsky , Michael Ellerman , Shawn Anastasio , Steven Price , Nicholas Piggin , Christian Brauner , Jens Axboe , Gabriel Krisman Bertazi , Peter Xu , Suren Baghdasaryan , Shakeel Butt , Marco Elver , Daniel Jordan , Nicolas Viennot , Thomas Cedeno , Collin Fijalkovich , Michal Hocko , Miklos Szeredi , Chengguang Xu , Christian =?iso-8859-1?Q?K=F6nig?= , "linux-unionfs@vger.kernel.org" , Linux API , the arch/x86 maintainers , "" , Linux-MM , Florian Weimer , Michael Kerrisk Subject: Re: Removing Mandatory Locks Message-ID: References: <87eeay8pqx.fsf@disp2133> <5b0d7c1e73ca43ef9ce6665fec6c4d7e@AcuMS.aculab.com> <87h7ft2j68.fsf@disp2133> <87k0kkxbjn.fsf_-_@disp2133> <0c2af732e4e9f74c9d20b09fc4b6cbae40351085.camel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=d3CMeAe9; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of ebiggers@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=ebiggers@kernel.org X-Stat-Signature: k97r8cau3f4oao1e6pith74ngon65fzk X-Rspamd-Queue-Id: 1A2056001986 X-Rspamd-Server: rspam05 X-HE-Tag: 1629402911-45166 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 19, 2021 at 12:15:08PM -0700, Linus Torvalds wrote: > On Thu, Aug 19, 2021 at 11:39 AM Jeff Layton wrote: > > > > I'm all for ripping it out too. It's an insane interface anyway. > > > > I've not heard a single complaint about this being turned off in > > fedora/rhel or any other distro that has this disabled. > > I'd love to remove it, we could absolutely test it. The fact that > several major distros have it disabled makes me think it's fine. > > But as always, it would be good to check Android. > > The desktop distros tend to have the same tools and programs, so if > Fedora and RHEL haven't needed it for years, then it's likely stale in > Debian too (despite being enabled). > > But Android tends to be very different. Does anybody know? > As far as I know, Android never uses mandatory file locking. While CONFIG_MANDATORY_LOCKING=y is typically set (as it's "default y" upstream), I can't find anywhere in the Android source tree that uses the "mand" mount option, let alone anything actually using mandatory locks. (I'm assuming that Documentation/filesystems/mandatory-locking.rst is up-to-date regarding what userspace actually has to do to use it.) - Eric