From: tytso@mit.edu Subject: Re: [PATCH 2.6.27.y 1/3] ext4: Use our own write_cache_pages() Date: Fri, 28 May 2010 20:49:13 -0400 Message-ID: <20100529004913.GL26177@thunk.org> References: <4C001888.8020006@jaysonking.com> <4C0018E1.5060007@jaysonking.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stable team , LKML , Greg Kroah-Hartman , "Aneesh Kumar K.V" , Dave Chinner , Ext4 Developers List , Kay Diederichs To: "Jayson R. King" Return-path: Received: from thunk.org ([69.25.196.29]:43669 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751442Ab0E2Atl (ORCPT ); Fri, 28 May 2010 20:49:41 -0400 Content-Disposition: inline In-Reply-To: <4C0018E1.5060007@jaysonking.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, May 28, 2010 at 02:26:25PM -0500, Jayson R. King wrote: > From: Theodore Ts'o > Date: Sun May 16 18:00:00 2010 -0400 > Subject: ext4: Use our own write_cache_pages() > > commit 8e48dcfbd7c0892b4cfd064d682cc4c95a29df32 upstream. > > Make a copy of write_cache_pages() for the benefit of > ext4_da_writepages(). This allows us to simplify the code some, and > will allow us to further customize the code in future patches. > > There are some nasty hacks in write_cache_pages(), which Linus has > (correctly) characterized as vile. I've just copied it into > write_cache_pages_da(), without trying to clean those bits up lest I > break something in the ext4's delalloc implementation, which is a bit > fragile right now. This will allow Dave Chinner to clean up > write_cache_pages() in mm/page-writeback.c, without worrying about > breaking ext4. Eventually write_cache_pages_da() will go away when I > rewrite ext4's delayed allocation and create a general > ext4_writepages() which is used for all of ext4's writeback. Until > now this is the lowest risk way to clean up the core > write_cache_pages() function. > > Signed-off-by: "Theodore Ts'o" This doesn't fix a bug; it's to make it easy for Dave Chinner to make some changes to fix XFS's performance and to undo some ext4-specific changes to write_cache_pages(). I'm not sure there's a good reason to backport this to 2.6.27.y.... - Ted