Help recovering damaged drive - fsck segfaults, read-only mount looks ok

[Matt Emmerton]

> > If I force a mount in readonly mode, I can inspect the drive and at 
> > first glance, everything seems valid.  Since this machine is used 
> > for backups, I have lots of other medata (eg, checksums) and I'm 
> > slowly working through to see if anything important is damaged.
>
> At this point: STOP.
> If your data is important to you, get a copy of it NOW.

Thanks to everyone who provided guidance here.

Since this was my backup system, I determined that there wasn't any value in
trying to restore the incremental history on it, and it would be best to
start fresh with a new filesystem and new backups, which are in progress
now.

Matt