From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755276AbZIAWQh (ORCPT ); Tue, 1 Sep 2009 18:16:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755260AbZIAWQh (ORCPT ); Tue, 1 Sep 2009 18:16:37 -0400 Received: from mail-ew0-f206.google.com ([209.85.219.206]:54517 "EHLO mail-ew0-f206.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755258AbZIAWQg (ORCPT ); Tue, 1 Sep 2009 18:16:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=hZNGc5QB8AY3dbYLgVoPUfSj/TP+rMUhooIxWCSz4QnmrXBbPwpPkR0J5JEXRbPzeU MMqtqymxB4yFT/upS9AfjHgxi0DwUIAThbCAIxB74sWqQTcJC5qUn/toIBbDs8u/5tqN wGWqZdZd2/wR3MkTy25MGghZe5NFEb4ghiD3E= Date: Wed, 2 Sep 2009 00:16:34 +0200 From: Frederic Weisbecker To: Alexander Beregalov Cc: LKML , Reiserfs Subject: Re: [PATCH 0/4] kill-the-bkl/reiserfs: fix some lock dependency inversions Message-ID: <20090901221631.GA6108@nowhere> References: <1251167570-5233-1-git-send-email-fweisbec@gmail.com> <20090826201330.GA18761@orion> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090826201330.GA18761@orion> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 27, 2009 at 12:13:30AM +0400, Alexander Beregalov wrote: > On Tue, Aug 25, 2009 at 04:32:46AM +0200, Frederic Weisbecker wrote: > > Hi, > > > > This small set fixes some lock dependency inversions found in reiserfs > > xattr and mmap paths. > > I guess there are still some of them that I'll have to hunt, especially one > > reported by Laurent Riffard and another one introduced by the reiserfs_readdir > > path optimization (though I'm not sure about the latter, I have yet to find a > > way to reproduce it properly). > > > > As usual, these patches can be found at: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git \ > > reiserfs/kill-bkl > > Hi, > possible circular locking dependency detected > > Is it false positive? No, this confirms a real one, also the worst because it has been introduced by a nice optimization (in term of result of throughput) that I'll probably need to revert. reiserfs_readdir() has a reiserfs_write_lock -> mm->mmap_sem dependency. But reiserfs_readpage() has a mm->mmap_sem -> reiserfs_write_lock dependency. I'll send a fix soon. Thanks a lot for this report Alexander! Frederic.