bin/54774: fsdb cannot use alternate superblocks

[dholland%eecs.harvard.edu@localhost]

>Number:         54774
>Category:       bin
>Synopsis:       fsdb cannot use alternate superblocks
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Dec 17 00:20:01 +0000 2019
>Originator:     David Holland
>Release:        NetBSD 9.99.17 (20191114)
>Organization:
>Environment:
System: NetBSD macaran 9.99.17 NetBSD 9.99.17 (MACARAN) #55: Thu Nov 14 16:56:47 EST 2019 dholland@macaran:/usr/src/sys/arch/amd64/compile/MACARAN amd64
Architecture: x86_64
Machine: amd64
>Description:

fsdb cannot read from alternate superblocks, which means that you
can't use it when you particularly need it with a toasted filesystem
image.

It completely refuses to run if it can't read the superblock at the
default location.

>How-To-Repeat:

man fsdb

>Fix: