"Cannot find file system superblock" error - how to recover?

[Malcolm Kay]

On Tue, 6 Jan 2004 15:38, Scott I. Remick wrote:
> --- Sergey 'DoubleF' Zaharchenko <doublef at tele-kom.ru> wrote:
> > > I wonder whether editing the label and setting both offsets to 0
> > > might solve the problem.
> >
> > It definitely seems like that, as the actual offset of the partition is
> > 0, as dd shows.
>
> Ok, sounds like a plan. Not that I know what I'm doing. Should I use
> something like the following command to save my current disklabel?
>
> bsdlabel /dev/ad6s1c > disklabel.ad6s1c.backup
>
> Then do I just edit a copy of that textfile, change the offsets to 0, then
> write it back like this?
>
> bsdlabel -R /dev/ad6s1c dislabel.ad6s1c.new
>
> And lastly... your talk about offsets. The man page for bsdlabel describes
> using it on the whole disk (ad6) and not a slice or partition. If I run it
> on  ad6, I get:
>
> bsdlabel: /dev/ad6: no valid label found
>

Beware; if you write a disklabel (or presumably bsdlabel; I have no experience 
with 5.x) to ad6 you create a "dangerously dedicated" 
disk, i.e. a disk without slices.

> If I run it on the slice ad6s1 I get:
>
> # /dev/ad6s1:
> 8 partitions:
> #        size   offset    fstype   [fsize bsize bps/cpg]
>   c: 156344517        0    unused        0     0         # "raw" part,
> don't edit
>   e: 156344517        0    4.2BSD     2048 16384    89
>
> And there I see the offset of 0 you might be talking about...? Are we
> looking at the proper label? Just want to make sure before I mess things
> up.
>

Are you saying that the disklabels reported for ad6s1 and ad6s1c are different?

Under FreeBSD 4.x ad6s1 and ad6s1c would normally be aliases referencing the 
entire slice. Maybe 5.x is different! I'm now very confused.

What is reported by fdisk?

Malcolm Kay

> Thanks!