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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D0B36C43466 for ; Mon, 21 Sep 2020 04:28:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D87AC20866 for ; Mon, 21 Sep 2020 04:28:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D87AC20866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D92DF900020; Mon, 21 Sep 2020 00:28:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D418990001E; Mon, 21 Sep 2020 00:28:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BBAE590001F; Mon, 21 Sep 2020 00:28:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0036.hostedemail.com [216.40.44.36]) by kanga.kvack.org (Postfix) with ESMTP id A4E27900018 for ; Mon, 21 Sep 2020 00:28:20 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 610B73623 for ; Mon, 21 Sep 2020 04:28:20 +0000 (UTC) X-FDA: 77285786760.25.scale40_1310ecd27142 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 332621804E3A0; Mon, 21 Sep 2020 04:28:20 +0000 (UTC) X-HE-Tag: scale40_1310ecd27142 X-Filterd-Recvd-Size: 2761 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf30.hostedemail.com (Postfix) with ESMTP; Mon, 21 Sep 2020 04:28:19 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 979FC68AFE; Mon, 21 Sep 2020 06:28:15 +0200 (CEST) Date: Mon, 21 Sep 2020 06:28:15 +0200 From: Christoph Hellwig To: Andy Lutomirski Cc: Al Viro , Matthew Wilcox , Christoph Hellwig , Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , linux-arm-kernel , X86 ML , LKML , "open list:MIPS" , Parisc List , linuxppc-dev , linux-s390 , sparclinux , linux-block , Linux SCSI List , Linux FS Devel , linux-aio , io-uring@vger.kernel.org, linux-arch , Linux-MM , Network Development , keyrings@vger.kernel.org, LSM List Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200921042815.GA16281@lst.de> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200920151510.GS32101@casper.infradead.org> <20200920180742.GN3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) 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 Sun, Sep 20, 2020 at 12:14:49PM -0700, Andy Lutomirski wrote: > I wonder if this is really quite cast in stone. We could also have > FMODE_SHITTY_COMPAT and set that when a file like this is *opened* in > compat mode. Then that particular struct file would be read and > written using the compat data format. The change would be > user-visible, but the user that would see it would be very strange > indeed. > > I don't have a strong opinion as to whether that is better or worse > than denying io_uring access to these things, but at least it moves > the special case out of io_uring. open could have happened through an io_uring thread a well, so I don't see how this would do anything but move the problem to a different place. > > --Andy ---end quoted text---