From: Greg KH Subject: Re: [PATCH] ext4: fix BUG_ON() in ext4_ext_insert_extent() for .32 longterm Date: Wed, 2 Nov 2011 14:00:24 -0700 Message-ID: <20111102210024.GA9949@kroah.com> References: <20110927193523.GB3309@thunk.org> <1317206703-5604-1-git-send-email-tm@tao.ma> <20111027094329.GB31921@thunk.org> <20111027115322.GB6379@kroah.com> <20111028023607.GA23772@gmail.com> <20111028052406.GA21306@kroah.com> <20111028084652.GA25104@gmail.com> <20111028090759.GA22822@kroah.com> <20111028123402.GA26003@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Ted Ts'o , Tao Ma , linux-ext4@vger.kernel.org, Xiaoyun Mao , Yingbin Wang , Jia Wan Received: from out5.smtp.messagingengine.com ([66.111.4.29]:53753 "EHLO out5.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752063Ab1KBVFv (ORCPT ); Wed, 2 Nov 2011 17:05:51 -0400 Content-Disposition: inline In-Reply-To: <20111028123402.GA26003@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Oct 28, 2011 at 08:34:02PM +0800, Zheng Liu wrote: > On Fri, Oct 28, 2011 at 11:07:59AM +0200, Greg KH wrote: > > On Fri, Oct 28, 2011 at 04:46:52PM +0800, Zheng Liu wrote: > > > On Fri, Oct 28, 2011 at 07:24:06AM +0200, Greg KH wrote: > > > > On Fri, Oct 28, 2011 at 10:36:08AM +0800, Zheng Liu wrote: > > > > > On Thu, Oct 27, 2011 at 01:53:22PM +0200, Greg KH wrote: > > > > > > On Thu, Oct 27, 2011 at 05:43:29AM -0400, Ted Ts'o wrote: > > > > > > > On Wed, Sep 28, 2011 at 06:45:03PM +0800, Tao Ma wrote: > > > > > > > > actually this bug does show up in 2.6.39 and I think stable tree still > > > > > > > > needs this fix. After some careful test, my colleague has generated > > > > > > > > the patch. Please considering ack it so that Greg can add it into the > > > > > > > > stable tree. > > > > > > > > > > > > > > Sorry for the delay, but yes. This patch would be good for the stable > > > > > > > tree for 2.6.39 (if Greg is still accepting patches for > > > > > > > 2.6.39-stable). It doesn't apply for upstream ext4 since the code has > > > > > > > been changed/refactored since then, but it's a good fix. > > > > > > > > > > > > No, .39 has not been maintained for quite some time now, sorry. > > > > > Hi Greg, > > > > > > > > > > Thank you for your attention. Actually this bug is between from .32 to > > > > > .39. Please considering to apply this patch to other stable or longterm > > > > > trees. > > > > > > > > Ah, ok, that makes sense, can you provide me a patch that will apply to > > > > the .32 and .33-longterm kernels? > > > Hi Greg, > > > > > > I couldn't download the .32 and .33-longterm kernels from kernel.org > > > because the full sources were not found on that server. Thus this patch > > > is generated from the .32-mainline kernel and can be applied to the .32 > > > and .33 kernels. > > > > The .32 and .33 longterm kernels are part of the linux-stable tree on > > git.kernel.org, they are in their own branch. Please redo this against > > those trees, as I'm pretty sure that there will be conflicts, due to all > > of the different changes since the .0 releases. > Hi Greg > > This patch is for .32 longterm kernel. Please try it again. > > regards, > Zheng > > >From bc522003378af679afd227ff87497dfb4fd4d652 Mon Sep 17 00:00:00 2001 > From: Zheng Liu > Date: Fri, 28 Oct 2011 19:41:19 +0800 > Subject: [PATCH] ext4: fix BUG_ON() in ext4_ext_insert_extent() > > We will meet with a BUG_ON() if following script is run. > > mkfs.ext4 -b 4096 /dev/sdb1 1000000 > mount -t ext4 /dev/sdb1 /mnt/sdb1 > fallocate -l 100M /mnt/sdb1/test > sync > for((i=0;i<170;i++)) > do > dd if=/dev/zero of=/mnt/sdb1/test conv=notrunc bs=256k count=1 > seek=`expr $i \* 2` > done > umount /mnt/sdb1 > mount -t ext4 /dev/sdb1 /mnt/sdb1 > dd if=/dev/zero of=/mnt/sdb1/test conv=notrunc bs=256k count=1 seek=341 > umount /mnt/sdb1 > mount /dev/sdb1 /mnt/sdb1 > dd if=/dev/zero of=/mnt/sdb1/test conv=notrunc bs=256k count=1 seek=340 > sync > > The reason is that it forgot to mark dirty when splitting two extents in > ext4_ext_convert_to_initialized(). Althrough ex has been updated in > memory, > it is not dirtied both in ext4_ext_convert_to_initialized() and > ext4_ext_insert_extent(). The disk layout is corrupted. Then it will > meet with > a BUG_ON() when writting at the start of that extent again. > > Cc: stable@kernel.org #for 2.6.32 > Cc: Greg Kroah-Hartman > Cc: "Theodore Ts'o" > Cc: Xiaoyun Mao > Cc: Yingbin Wang > Cc: Jia Wan > Signed-off-by: Zheng Liu Sorry for dragging this out, but what commit id does this correspond to in Linus's tree? I can't seem to figure it out. Or does it not correspond to anything? If so, I need a sentence that says why it doesn't for the patch changelog. thanks, greg k-h