NetBSD 9.1 upgrade and file system crash - reboot fails

[Riccardo Mottola <riccardo.mottola%libero.it@localhost>]

Hi!

I just updated to NetBSD 9.1! Yay, it was smooth, CD in, upgrade, then 
pkgin... and be happy.
Genuine amd64 laptop.

Use it 10 minutes, launch an intensive disk task (git pull) and Bam! I 
get kernel panic because of ufs (free list.. soemthing about something 
already free). I am unable to take a screeshot and the laptop reboots

Once it reboots, the filesystem checks fail:

Starting root file systems check:
15526 DUP I=155
/dev/rwd0a: UNEXPECTED INCONSITENCY; RUN fsck_ffs MANUALLY.

ouch so I had a panick and the filesystem is so bad?

I did run then "fsck_ffs -y /dev/rwd0a"

A lot of errors.... and the system is not bootable anymore! I get:
NetBSD MBR boot....
Non-System disk or disk error

so bad??

If I boot from the CD I can mount the target filesystem disk and see 
most of my files. What now? Upgrade in place second time? reinstall boot 
loader?

I did run on this machine 9.99 kernel on 9.0 userland for some time 
(testing some patches that made it indeed into release or it wouldn't 
have booted) and it was quite stable even under high load, building, etc.

Riccardo