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=-1.1 required=3.0 tests=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 1169FC3A589 for ; Thu, 15 Aug 2019 19:18:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDDC720656 for ; Thu, 15 Aug 2019 19:18:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565896728; bh=xb3DyN7+JjEreEpTFI2Ds9GHRndFIqFAERtGNbOWS7Y=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-ID:From; b=VVY3B+GPwA2nGadgdPudoeiZ5TwoxUOPopFMGGtUimADijHE/L5BVxLfJ3bKNAZw5 vfNitaBlq0qe4kQQlFS8YH8DLdhU8wCjgyoXckIFIwbXHAFeWtlRr1fFrpAAWX2Fp0 zWu2GzTMUJKWxxR7wp0aq93QqijRJjr/K8q7D6so= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731970AbfHOTSs (ORCPT ); Thu, 15 Aug 2019 15:18:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:55228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731622AbfHOTSs (ORCPT ); Thu, 15 Aug 2019 15:18:48 -0400 Received: from tleilax.poochiereds.net (68-20-15-154.lightspeed.rlghnc.sbcglobal.net [68.20.15.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E467920656; Thu, 15 Aug 2019 19:18:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565896727; bh=xb3DyN7+JjEreEpTFI2Ds9GHRndFIqFAERtGNbOWS7Y=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=IwBwr4X7s6UUHdEn1pqVL9Ih31e97AG9B5E6L1EEtU+w1kICT77efALfAX80qMHgv uV84QgbrpemnviUcI1i3vtF3aZ+rWXMmAQBUvcy/zGRntno9fSGO8sWI6zilPB2+VQ huE5hvP3Z7Qp9yTnewO3qIk0mHQsIXfTwPL5FwwY= Message-ID: <01b6620186a18b167ca1bab1fadb2dbaffdd8379.camel@kernel.org> Subject: Re: Deprecated mandatory file locking From: Jeff Layton To: Jan Kara Cc: linux-fsdevel@vger.kernel.org Date: Thu, 15 Aug 2019 15:18:45 -0400 In-Reply-To: <20190814174604.GC10843@quack2.suse.cz> References: <20190814173345.GB10843@quack2.suse.cz> <20190814174604.GC10843@quack2.suse.cz> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.4 (3.32.4-1.fc30) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, 2019-08-14 at 19:46 +0200, Jan Kara wrote: > Resending to proper Jeff's address... > > On Wed 14-08-19 19:33:45, Jan Kara wrote: > > Hello Jeff, > > > > we've got a report from user > > (https://bugzilla.suse.com/show_bug.cgi?id=1145007) wondering why his fstab > > entry (for root filesystem!) using 'mand' mount option stopped working. > > Now I understand your rationale in 9e8925b67a "locks: Allow disabling > > mandatory locking at compile time" but I guess there's some work to do wrt > > documentation. At least mount(8) manpage could mention that mandatory > > locking is broken and may be disabled referencing the rationale in fcntl > > manpage? Or the kernel could mention something in the log about failing > > mount because of 'mand' mount option? What do you think? Because it took > > me some code searching to understand why the mount is actually failing > > which we can hardly expect from a normal sysadmin... > > > > Honza Wow, I think this is the first actual user fallout we've ever had from that change! Why was he setting that option? Does he actually use mandatory locking? I think a pr_notice() or pr_warn() at mount time when someone tries to use it sounds like a very reasonable thing to do. Perhaps we can just stick one in may_mandlock()? I'll draft up a patch, and also update Documentation/filesystems/mandatory-locking.txt with the current situation. Thanks, -- Jeff Layton