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=-2.2 required=3.0 tests=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 ADF7EC55185 for ; Wed, 22 Apr 2020 16:10:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8ECA920774 for ; Wed, 22 Apr 2020 16:10:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726517AbgDVQKc (ORCPT ); Wed, 22 Apr 2020 12:10:32 -0400 Received: from mx2.suse.de ([195.135.220.15]:36312 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726183AbgDVQKb (ORCPT ); Wed, 22 Apr 2020 12:10:31 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id A134AAED7; Wed, 22 Apr 2020 16:10:29 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id BA3291E0E56; Wed, 22 Apr 2020 18:10:29 +0200 (CEST) Date: Wed, 22 Apr 2020 18:10:29 +0200 From: Jan Kara To: Ira Weiny Cc: "Theodore Y. Ts'o" , Ext4 Developers List , syzkaller-bugs@googlegroups.com, stable@kernel.org, syzbot+bca9799bf129256190da@syzkaller.appspotmail.com Subject: Re: [PATCH] ext4: reject mount options not supported when remounting in handle_mount_opt() Message-ID: <20200422161029.GD20756@quack2.suse.cz> References: <20200415174839.461347-1-tytso@mit.edu> <20200415202537.GA2309605@iweiny-DESK2.sc.intel.com> <20200415220752.GA5187@mit.edu> <20200416052352.GK2309605@iweiny-DESK2.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200416052352.GK2309605@iweiny-DESK2.sc.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed 15-04-20 22:23:52, Ira Weiny wrote: > On Wed, Apr 15, 2020 at 06:07:52PM -0400, Theodore Y. Ts'o wrote: > > On Wed, Apr 15, 2020 at 01:25:37PM -0700, Ira Weiny wrote: > > > This fundamentally changes the behavior from forcing the dax mode to be the > > > same across the remount to only failing if we are going from non-dax to dax, > > > adding -o dax on the remount? > > > > > > But going from -o dax to 'not -o dax' would be ok? > > > > > > FWIW after thinking about it some I _think_ it would be ok to allow the dax > > > mode to change on a remount and let the inodes in memory stay in the mode they > > > are at. And newly loaded inodes would get the new mode... Unfortunately > > > without the STATX patch I have proposed the user does not have any way of > > > knowing which files are in which mode. > > > > We don't currently support mount -o nodax. > > But we do support not supplying the option which means 'nodax' right? Yeah, I second what Ira wrote. The new code does not seem to properly detect a case when enabled mount option is removed for remount and thus the feature would get disabled during remount as a result... Honza -- Jan Kara SUSE Labs, CR