From: "Darrick J. Wong" Subject: Re: [PATCHSET v3.1 0/7] data integrity: Stabilize pages during writeback for various fses Date: Wed, 11 May 2011 11:19:01 -0700 Message-ID: <20110511181901.GK20579@tux1.beaverton.ibm.com> References: <20110509230318.19566.66202.stgit@elm3c44.beaverton.ibm.com> <20110510125124.GD4402@quack.suse.cz> Reply-To: djwong@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Tso , Alexander Viro , OGAWA Hirofumi , Jens Axboe , "Martin K. Petersen" , Jeff Layton , Dave Chinner , linux-kernel , Dave Hansen , Christoph Hellwig , linux-mm@kvack.org, Chris Mason , Joel Becker , linux-scsi , linux-fsdevel , linux-ext4@vger.kernel.org, Mingming Cao To: Jan Kara Return-path: Received: from e3.ny.us.ibm.com ([32.97.182.143]:34909 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751331Ab1EKSTF (ORCPT ); Wed, 11 May 2011 14:19:05 -0400 Content-Disposition: inline In-Reply-To: <20110510125124.GD4402@quack.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, May 10, 2011 at 02:51:24PM +0200, Jan Kara wrote: > On Mon 09-05-11 16:03:18, Darrick J. Wong wrote: > > I am still chasing down what exactly is broken in ext3. data=writeback mode > > passes with no failures. data=ordered, however, does not pass; my current > > suspicion is that jbd is calling submit_bh on data buffers but doesn't call > > page_mkclean to kick the userspace programs off the page before writing it. > Yes, ext3 in data=ordered mode writes pages from > journal_commit_transaction() via submit_bh() without clearing page dirty > bits thus page_mkclean() is not called for these pages. Frankly, do you > really want to bother with adding support for ext2 and ext3? People can use > ext4 as a fs driver when they want to start using blk-integrity support. > Especially ext2 patch looks really painful and just from a quick look I can > see code e.g. in fs/ext2/namei.c which isn't handled by your patch yet. Yeah, I agree that ext2 is ugly and ext3/jbd might be more painful. Are there any other code that wants stable pages that's already running with ext3? In this months-long discussion I've heard that encryption and raid also like stable pages during writes. Have those users been broken this whole time, or have they been stabilizing pages themselves? I suppose we can cross the "ext3 fails horribly on DIF" bridge when someone complains about it. Possibly we could try to steer them to btrfs. --D