linux-ext4 - Re: [PATCH] e2fsck: detect invalid extents at the end of an extent-block

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Message-ID: <20130607033508.GA7555@thunk.org>
Date:	Thu, 6 Jun 2013 23:35:08 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	David Jeffery <djeffery@...hat.com>, linux-ext4@...r.kernel.org
Subject: Re: [PATCH] e2fsck: detect invalid extents at the end of an
 extent-block

On Tue, Jun 04, 2013 at 02:53:51PM -0500, Eric Sandeen wrote:
> 
> Here's an image which demonstrates this, current e2fsck does not detect
> the error.

Thanks.  For future reference, here's how you can use debugfs to
generate a much smaller image which demonstrates the problem, suitable
for use in a regression test.

					- Ted

#!/bin/sh
dd if=/dev/zero of=image bs=1k count=256
mke2fs -Ft ext4 image
debugfs -w image << EOF
write /dev/null testfile
extent_open testfile
  insert_node 0 15 100
  insert_node --after 15 15 115
  insert_node --after 30 15 130
  insert_node --after 45 15 145
  split
  down
  split
  root
  down
  next
  replace_node 15 30 200
  extent_close
set_inode_field testfile i_size 61400
set_inode_field testfile i_blocks 154
setb 100 15
setb 130 30
setb 200 30
set_bg 0 free_blocks_count 156
set_bg 0 bg_checksum calc
set_super_value free_blocks_count 156
EOF

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