From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753215Ab0G0SB6 (ORCPT ); Tue, 27 Jul 2010 14:01:58 -0400 Received: from cantor.suse.de ([195.135.220.2]:47202 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753021Ab0G0SB5 (ORCPT ); Tue, 27 Jul 2010 14:01:57 -0400 Date: Tue, 27 Jul 2010 20:01:31 +0200 From: Jan Kara To: Christoph Hellwig Cc: Jan Kara , LKML , Andrew Morton Subject: Re: [PATCH 1/3] bdi: Use parent filesystem BDI for inodes not capable of writeback Message-ID: <20100727180131.GG6820@quack.suse.cz> References: <1280250301-17603-1-git-send-email-jack@suse.cz> <1280250301-17603-2-git-send-email-jack@suse.cz> <20100727170903.GA9034@infradead.org> <20100727172437.GE6820@quack.suse.cz> <20100727172731.GA25727@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100727172731.GA25727@infradead.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 27-07-10 13:27:31, Christoph Hellwig wrote: > On Tue, Jul 27, 2010 at 07:24:38PM +0200, Jan Kara wrote: > > Always returning inode->i_sb->s_bdi wouldn't be a right thing IMHO. > > That would file inode for /dev/sda to BDI list of tmpfs mounted on /dev/ > > which isn't what you want... > > It shouldn't. Block device nodes are on the bdev filesystems, and Ok, so inode->i_sb->s_bdi will actually point to noop_backing_dev_info as set by set_anon_super(). Or am I completely out? > we twist the file->mapping pointer so that all the low-level read/write > code always deals with the bdev fs inode, and not the device node > filesystem. Yes, I know this but I fail to see how this influences where ->i_sb->s_bdi ends up... Honza -- Jan Kara SUSE Labs, CR