Floating point exception with a ext3 journal device

[Felix Zielcke]

If you create a journal device with `mke2fs -O journal_dev /dev/sdxy'
and then do `ls (hdx,y)' or `search /' then grub-emu crashes with a FPE
This has been reported on Debian http://bugs.debian.org/502333
The problem lies in fs/ext2.c:466
  grub_ext2_blockgroup (data,
                        ino / grub_le_to_cpu32 (sblock->inodes_per_group),
                        &blkgrp);
sblock->inodes_per_group is zero for a journal device.
I think the best solution would be Javier's patch which refuses extN
filesystems with invalid flags, because journal devices have a INCOMPAT
flag journal_dev set
Else I don't know how to fix this.

-- 
Felix Zielcke