From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:40214 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755381AbbFQRBU (ORCPT ); Wed, 17 Jun 2015 13:01:20 -0400 Date: Wed, 17 Jun 2015 19:01:18 +0200 From: David Sterba To: Liu Bo Cc: dsterba@suse.cz, linux-btrfs@vger.kernel.org, fdmanana@suse.com Subject: Re: [RFC PATCH v2 1/2] Btrfs: add noi_version option to disable MS_I_VERSION Message-ID: <20150617170118.GA6761@twin.jikos.cz> Reply-To: dsterba@suse.cz References: <1434527672-5762-1-git-send-email-bo.li.liu@oracle.com> <20150617153306.GY6761@twin.jikos.cz> <20150617155234.GB7773@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150617155234.GB7773@localhost.localdomain> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Wed, Jun 17, 2015 at 11:52:36PM +0800, Liu Bo wrote: > On Wed, Jun 17, 2015 at 05:33:06PM +0200, David Sterba wrote: > > On Wed, Jun 17, 2015 at 03:54:31PM +0800, Liu Bo wrote: > > > MS_I_VERSION is enabled by default for btrfs, this adds an alternative > > > option to toggle it off. > > > > There's an existing generic iversion/noiversion mount option pair, no > > need to extra add it to btrfs. > > I know, it doesn't work though. Sigh, I see, btrfs forces MS_I_VERSION flag, 0c4d2d95d06e920e0c61707e62c7fffc9c57f63a. I read 'enabled by default' as that there's a standard way to override the defaults. So the right way is not to do that but this will break everyhing that relies on that behaviour at the moment. This means to add the exception to the upper layers, either VFS or 'mount', which is not very likely to happen. The generic options do not reach the filesystem specific callbacks, so we can't check it.