From: Nick Piggin Subject: Re: + fs-introduce-write_begin-write_end-and-perform_write-aops.patch added to -mm tree Date: Thu, 14 Jun 2007 12:39:03 +0200 Message-ID: <20070614103903.GA6703@wotan.suse.de> References: <200705292119.l4TLJtAD011726@shell0.pdx.osdl.net> <20070613134005.GA13815@localhost.sw.ru> <20070613114356.GD17547@wotan.suse.de> <1181776021.21924.87.camel@dyn9047017100.beaverton.ibm.com> <20070614095249.GG17819@atrey.karlin.mff.cuni.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Badari Pulavarty , lkml , mark.fasheh@oracle.com, ext4 , Andrew Morton , cmm@us.ibm.com To: Jan Kara Return-path: Received: from ns1.suse.de ([195.135.220.2]:56079 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751235AbXFNKjL (ORCPT ); Thu, 14 Jun 2007 06:39:11 -0400 Content-Disposition: inline In-Reply-To: <20070614095249.GG17819@atrey.karlin.mff.cuni.cz> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, Jun 14, 2007 at 11:52:49AM +0200, Jan Kara wrote: > > On Wed, 2007-06-13 at 13:43 +0200, Nick Piggin wrote: > > .. > > > > > > > 5) ext3_write_end: > > > > Before write_begin/write_end patch set we have folowing locking > > > > order: > > > > stop_journal(handle); > > > > unlock_page(page); > > > > But now order is oposite: > > > > unlock_page(page); > > > > stop_journal(handle); > > > > Can we got any race condition now? I'm not sure is it actual problem, > > > > may be somebody cant describe this. > > > > > > Can we just change it to the original order? That would seem to be > > > safest unless one of the ext3 devs explicitly acks it. > Sorry, I've missed beginning of this thread. But what problems can > exactly cause this ordering change? ext3_journal_stop has no need to be > protected by the page lock - it can be even better that it's not > protected as it can trigger commit and all that would happen > unnecessarily under page lock... Sure, if you think it is safe. I would rather it be done in a different patch though.