From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752557Ab0G0UVl (ORCPT ); Tue, 27 Jul 2010 16:21:41 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:46433 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704Ab0G0UVk (ORCPT ); Tue, 27 Jul 2010 16:21:40 -0400 Date: Tue, 27 Jul 2010 16:21:29 -0400 From: Christoph Hellwig To: Jan Kara Cc: Christoph Hellwig , LKML , Andrew Morton Subject: Re: [PATCH 1/3] bdi: Use parent filesystem BDI for inodes not capable of writeback Message-ID: <20100727202129.GA28641@infradead.org> 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> <20100727180131.GG6820@quack.suse.cz> <20100727201207.GA16335@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100727201207.GA16335@infradead.org> User-Agent: Mutt/1.5.20 (2009-08-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 27, 2010 at 04:12:07PM -0400, Christoph Hellwig wrote: > On Tue, Jul 27, 2010 at 08:01:31PM +0200, Jan Kara wrote: > > > 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? > > I think you're right. This seems rather bad if it's indeed true. I'll > quickly verify it using Dave's new tracing once I've built a block > tree kernel. Indeed it does. So using ->s_bdi actually is wrong for the block device node, given that it does set up the bdevfs inode's backing_dev_info to the proper one, but can't actually do it for the per-sb one.