From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [RFC] vfs/inode: For none-block-based filesystems default to sb->s_bdi Date: Tue, 5 Oct 2010 17:12:10 +0200 Message-ID: <20101005151210.GC14516@quack.suse.cz> References: <4CAA4B1D.1010904@panasas.com> <4CAA4EE5.2070308@panasas.com> <20101005083208.GA3514@quack.suse.cz> <4CAB2DE5.90801@panasas.com> <4CAB2E29.3080806@panasas.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Christoph Hellwig , Al Viro , linux-fsdevel , Trond Myklebust , Benny Halevy To: Boaz Harrosh Return-path: Received: from cantor.suse.de ([195.135.220.2]:52837 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754043Ab0JEPNF (ORCPT ); Tue, 5 Oct 2010 11:13:05 -0400 Content-Disposition: inline In-Reply-To: <4CAB2E29.3080806@panasas.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue 05-10-10 09:54:49, Boaz Harrosh wrote: > On 10/05/2010 09:53 AM, Boaz Harrosh wrote: > > On 10/05/2010 04:32 AM, Jan Kara wrote: > >> Hi Boaz, > >> > >> On Mon 04-10-10 18:02:13, Boaz Harrosh wrote: > >>> Sorry I've just seen Jan's patch: > >>> From: Jan Kara > >>> Date: Mon, 27 Sep 2010 23:56:48 +0200 > >>> Subject: [PATCH] bdi: Initialize inode->i_mapping.backing_dev_info to sb->s_bdi > >> ... > >>> That works for me as well. Was it decided how to solve this? Other wise > >>> I'll need to patch exofs, ASAP for this -rc > >> In the end, we'll use Christoph's patch > >> (http://lkml.org/lkml/2010/9/29/76) changing inode_to_bdi() to be > >> more conservative and also the warning will be gone. So you don't have to > >> patch anything... > >> > >> Honza > > > > I would still like to fix it. Currently each inode->mapping.backing_dev_info in my > > none-block-filesystem is set to &default_backing_dev_info. This sounds scary! > > what about the future patches that will schedule a wakup on set_inode_dirty ? > > Will they not need my proper sb->s_bdi on each ->mapping? > > > > I could do it in the filesystem, but the way the code is now I'll need to > > set it in 5 different places, or clean up the code with more common code. > > > > That said, I think your (or my) patch makes much more sense. The sb->s_bdi > > is a much better common default then &default_backing_dev_info. By now > > is &default_backing_dev_info really needed at all? > > > > I guess I'll have to go head and do it in FS code. > > > > BTW: I liked that WARN_ON it exposed a real problem. In fact, it exposed too many of them for being so late in the -rc cycle ;). Luckily they were all harmless (at least currently). So for now we are better off without the warning so that we don't scare users. Honza -- Jan Kara SUSE Labs, CR