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

[Sergey 'DoubleF' Zaharchenko]

On Tue, 6 Jan 2004 19:57:09 +1030
Malcolm Kay <malcolm.kay at internode.on.net> probably wrote:

> 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 maybe prefix that by a

$ bsdlabel -R /dev/ad6s1c dislabel.ad6s1c.new

which would just check your new layout for errors, without writing
anything, and print your file out as disklabel understands it.

> > 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

It can't be fdisk that you are reading about?

> > 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.

And of course the label isn't there, just because nobody wanted a `DD' disk.

> > 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?

And the `new' one seems to be correct for a 80G drive (+- a couple of
megabytes)? Have you touched anything?

Now, mount might work.

> 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.

Uhum. disklabel said that the offset was 63 in your previous posting, didn't it? 
What does

# ls -l /dev/ad6s1 /dev/ad6s1c

say? Any differences? I have none.

> What is reported by fdisk?

Let me guess: a single large slice.

> Malcolm Kay
> 
> > Thanks!
> 
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-- 
DoubleF
[Sir Stafford Cripps] has all the virtues I dislike and none of the
vices I admire.
		-- Winston Churchill
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