linux-ext4 - Re: [PATCH] libext2fs: Fix rbtree backend for extent lengths greater than 2^32

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Message-ID: <20120528021447.GE19152@thunk.org>
Date:	Sun, 27 May 2012 22:14:47 -0400
From:	Ted Ts'o <tytso@....edu>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	ext4 development <linux-ext4@...r.kernel.org>,
	Lukáš Czerner <lczerner@...hat.com>
Subject: Re: [PATCH] libext2fs: Fix rbtree backend for extent lengths
 greater than 2^32

On Fri, May 25, 2012 at 02:43:53PM -0500, Eric Sandeen wrote:
> Well, this took way too long to find, in retrospect.
> 
> In short, for a completely full filesystem with more than 2^32
> blocks, the rbtree bitmap backend can assemble an extent of used
> blocks which is longer than 2^32.  If it does, it will overflow
> ->count, and corrupt the rbtree for the bitmaps.
> 
> Discovered by completely filling a 32T filesystem using fallocate, and
> then observing debugfs, dumpe2fs, and e2fsck all behaving badly.
> 
> (Note that filling with only 31 x 1T files did not show the problem,
> because freespace was fragmented enough that there was no sufficiently
> long range of used blocks.)
> 
> Signed-off-by: Eric Sandeen <sandeen@...hat.com>

Thanks, applied.

						- Ted
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