[Techtalk] Bad Superblocks

[Maria Blackmore]

On Sat, 30 Nov 2002, Conor Daly wrote:

> On Fri, Nov 29, 2002 at 11:27:47PM -0600 or so it is rumoured hereabouts, 
> >       I have copied the two partitions into files using dd. That was
> > "successful" -- I can scan the images with hexdump -c, pipe to more,
> > and search for text strings to see what's on the drive. (I'm in the
> > matrix, woohoo.)
> Can you loop mount the _files_?  Though, if you're having trouble mounting
> the partitions, it's not very likely you'll be able to mount the files
> either.

I think it's worth a try

> > is corrupt, and you might try running e2fsck with an alternate superblock:
> >     e2fsck -b 8193 
>       ^^^^^^^^^^^^^^
> Did you try this?

If this doesn't find the backup superblock, it might be because the
filesystem was created with a block size other than 1k.  From the
e2fsck(8) man page:

	The location of the backup superblock is dependent on the
	filesystem's blocksize.  For filesystems with 1k blocksizes,
	a backup superblock can be found at block 8193; for filesystems
	with 2k blocksizes, at block 16384; and for 4k blocksizes,
	at block 32768.

Whilst going through this I would strongly recommend that e2fsck is run
with the -n option until you know if any data on the partition is going to
get mashed up.

Good luck, I would try to add some more useful suggestions here, but I'm
rather too tired to, sorry.

Maria