From: Peter Zijlstra Subject: Re: [EXT4 set 5][PATCH 1/1] expand inode i_extra_isize to support features in larger inode Date: Sun, 15 Jul 2007 22:13:20 +0200 Message-ID: <1184530400.5284.111.camel@lappy> References: <1183275482.4010.133.camel@localhost.localdomain> <20070710163247.5c8bfa3f.akpm@linux-foundation.org> <20070713020529.1486491f.akpm@linux-foundation.org> <1184333621.20032.85.camel@twins> <20070713121259.20066d5b.akpm@linux-foundation.org> <20070713214746.GH23255@mami.zabbo.net> <1184504543.5284.96.camel@lappy> <20070715111109.a2775ae4.akpm@linux-foundation.org> <1184527263.5284.110.camel@lappy> <20070715125921.87574a3a.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Zach Brown , cmm@us.ibm.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, Andy Whitcroft , Ingo Molnar To: Andrew Morton Return-path: Received: from canuck.infradead.org ([209.217.80.40]:33984 "EHLO canuck.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751412AbXGOUOP (ORCPT ); Sun, 15 Jul 2007 16:14:15 -0400 In-Reply-To: <20070715125921.87574a3a.akpm@linux-foundation.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Sun, 2007-07-15 at 12:59 -0700, Andrew Morton wrote: > On Sun, 15 Jul 2007 21:21:03 +0200 Peter Zijlstra wrote: > > > Shows the current stacktrace where we violate the previously established > > locking order. > > yup, but the lock_page() which we did inside truncate_mutex was a > lock_page() against a different address_space: the blockdev mapping. > > So this is OK - we'll never take truncate_mutex against the blockdev > mapping (it doesn't have one, for a start ;)) > > This is similar to the quite common case where we take inode A's > i_mutex inside inode B's i_mutex, which needs special lockdep annotations. > > I think. I haven't looked into this in detail. Right, I can make lock_page classes per address space. Lets see if this one goes away.