linux-ext4 - Re: ext4_ext_check_inode: bad header/extent in inode

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Message-ID: <20090424115816.GC7949@mit.edu>
Date:	Fri, 24 Apr 2009 07:58:16 -0400
From:	Theodore Tso <tytso@....edu>
To:	Andreas Dilger <adilger@....com>
Cc:	Christian Kujau <lists@...dbynature.de>,
	Eric Sandeen <sandeen@...hat.com>, linux-ext4@...r.kernel.org
Subject: Re: ext4_ext_check_inode: bad header/extent in inode

On Fri, Apr 24, 2009 at 01:09:43AM -0600, Andreas Dilger wrote:
> On Apr 23, 2009  23:20 -0400, Theodore Ts'o wrote:
> > On Thu, Apr 23, 2009 at 03:15:10PM -0700, Christian Kujau wrote:
> > > On Thu, 23 Apr 2009, Theodore Tso wrote:
> > > > Eventually I might need a raw e2image dump, i.e.:
> > > > 
> > > > 	   e2image -r /dev/md0 - | bzip2 > /var/tmp/md0.e2i.bz2
> > > 
> > > I've put the raw e2image dump on http://nerdbynature.de/bits/2.6.30-rc2/
> > > Do you still need the dump without the "-r"?
> > 
> > Nope, the raw e2image file was perfect.  This was actually a problem I
> > knew about, and wanted to get fixed before the e2fsprogs 1.41.5
> > release.  The problem was that i_file_acl_high was set and the kernel
> > unconditionally checks for it even though the INCOMPAT_64_BITS flag is
> > not set.
> 
> Maybe I'm missing something, but how can i_file_acl_high being used
> cause a problem with the file extent maps?

It didn't; what had happened was that a garbage block had got written
into the inode table.  This caused the kernel to complain about
eh_magic being wrong in the inode table.  E2fsck 1.41.3 fixed those
problems, but it ignored i_file_acl_high because the 64 bit feature
flag was not set.  The kernel always pays attention to
i_file_acl_high, regardless of whether the 64-bit feature flag is set
or not.  Hence, the kernel was complaining and refused to touch those
inodes.   

Actually, on a 2.6.30 kernel it causes the kernel to loop forever with
kernel messages "__find_get_block_slow() failed."

In any case, with e2fsck 1.41.5, I added code to fix i_file_acl_high
getting set, and I was then able to mount the raw e2image file and not
have any problems accessing the files in question, so I'm pretty sure
that was the problem.

						- Ted
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