Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754590Ab0F0XKJ (ORCPT ); Sun, 27 Jun 2010 19:10:09 -0400 Received: from ironport2-out.teksavvy.com ([206.248.154.181]:9972 "EHLO ironport2-out.pppoe.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754106Ab0F0XKH (ORCPT ); Sun, 27 Jun 2010 19:10:07 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApIBAOt2J0xLd/sX/2dsb2JhbAAHgxbLFY9+gSmDCXIE X-IronPort-AV: E=Sophos;i="4.53,492,1272859200"; d="scan'208";a="68998615" Message-ID: <4C27DA4A.3040708@teksavvy.com> Date: Sun, 27 Jun 2010 19:10:02 -0400 From: Mark Lord User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-GB; rv:1.9.1.10) Gecko/20100512 Thunderbird/3.0.5 MIME-Version: 1.0 To: Jens Axboe CC: Brian Bloniarz , Linus Torvalds , "linux-kernel@vger.kernel.org" , Christoph Hellwig Subject: Re: [GIT PULL] block/io bits for 2.6.35-rc References: <4C10EC2A.8060002@fusionio.com> <4C1111ED.6020008@fusionio.com> <4C111685.8010400@athenacr.com> In-Reply-To: <4C111685.8010400@athenacr.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2455 Lines: 54 On 10/06/10 12:44 PM, Brian Bloniarz wrote: > On 06/10/2010 12:25 PM, Jens Axboe wrote: >> On 2010-06-10 17:55, Linus Torvalds wrote: >>> On Thu, Jun 10, 2010 at 6:44 AM, Jens Axboe wrote: >>>> >>>> - A set of patches fixing the WB_SYNC_NONE writeback from Christoph. So >>>> we should finally have both functional and working WB_SYNC_NONE from >>>> umount context. >>> >>> I _really_ think this is too late, considering how broken it has been. >>> We already reverted the WB_SYNC_NONE things exactly because it didn't >>> work, didn't we? I'm going to be off-line in two days, and this part >>> of the pull request really makes me nervous, if only simply because of >>> the history of it all (ie it's always been broken, why shouldn't it be >>> broken now?). >>> >>> IOW, that's a lot of scary changes, that have historically not been >>> safe or sufficiently tested, and have caused problems for various >>> filesystems. Convince me why they should suddenly be ok to merge? >> >> I agree, it's late and it makes me nervous too. I had them cook for >> a day, didn't see any problems. And Christoph would not send it in >> unless it passes at least xfs qa, which is what found the problems >> last time (the ones we reverted). >> >> It's fixing a regression where umount takes a LONG time if you have >> a lot of dirty inodes, since it basically degenerates to a data >> integrity writeback instead of a simple WB_SYNC_NONE. If it wasn't >> fixing a nasty regression (the distros are all wanting a real fix >> for this, it's a user problem), I would not be submitting this code >> at this point in time. >> > > Reinforcing that last point: from what I could figure out, Fedora 13 > is shipping the buggy WB_SYNC_NONE patch currently. Ubuntu 10.04 is > shipping an in-kernel workaround that has serious performance > drawbacks. > > https://bugzilla.kernel.org/show_bug.cgi?id=15906 has links to the > downstream bugs. .. Jens, this bug has been biting my servers badly here for the past few months -- umount after a backup (from ext4 to ext4) takes 3-4 minutes instead of the expected 3-4 seconds. Is there a patch file for this against 2.6.34 that I (and others) could use? Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/