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Subject: Re: fs corruption report
From: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
To: Zooko Wilcox-OHearn <zooko@leastauthority.com>
CC: Marc Dietrich <marvin24@gmx.de>, <linux-btrfs@vger.kernel.org>
Date: Thu, 4 Sep 2014 11:00:55 +0800
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On Mon, 2014-09-01 at 15:25 +0000, Zooko Wilcox-OHearn wrote:
> I'm more than happy to try out patches and even focus my own brain on
> diagnosing it, if I can. I'm hoping to regain access to some of my
> files on my btrfs partition, and also I would enjoy helping get this
> improved. :-)
> 
> So if you want me to try an experiment, just email me. Unfortunately I
> can't just give you a copy of the partition, since it has confidential
> information on it.
> 
> Regards,
> 
> Zooko

Hi Zooko, Marc,

Firstly, thanks for your backtrace info, Marc.
Sorry to reply late, since I'm offline these days.
For the restore problem, I'm sure that the lzo decompress routine lacks
the ability to handle some specific extent pattern.

Here is my test result:
I'm using a specific file for test
/usr/lib/modules/$(uname -r)/kernel/net/irda/irda.ko.
You can get it easily on your own box.

	# mkfs -t btrfs <dev>
	# mount -o compress-force=lzo <dev> <mnt>
	# cp irda.ko <mnt>
	# umount <dev>
	# btrfs restore -v <dev> <restore_dir>
report:
	# bad compress length
	# failed to inflate

btrfs-progs version: v3.16.x

With the same file under no-compress & zlib-compress,
the restore will output a correct copy of irda.ko.

I'm not sure whether the problem above has something to do with your
problem. Hope that the messages above are helpful.

-Gui