kern/50000: lfs is limited to 2TB volumes

[dholland%NetBSD.org@localhost]

>Number:         50000
>Category:       kern
>Synopsis:       lfs is limited to 2TB volumes
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jun 26 04:55:00 +0000 2015
>Originator:     David A. Holland
>Release:        7.99.17 (20150519)
>Organization:
>Environment:
System: NetBSD macaran 7.99.17 NetBSD 7.99.17 (MACARAN) #26: Fri May 22 18:22:29 EDT 2015  dholland@macaran:/usr/src/sys/arch/amd64/compile/MACARAN amd64
Architecture: x86_64
Machine: amd64
>Description:

While the ufs-level ffsv2 code was merged into lfs, only enough was
done to make it compile, not run. You can't actually create a volume
that uses v2 inodes with 64-bit block pointers; nor if you managed to
create one would it be able to run.

>How-To-Repeat:

Attempt newfs_lfs on a shingled disk. Then, read the code. Remember
that one had already ascertained some time back that it wasn't
actually hooked up.

>Fix:

One needs to define the 64-bit on-disk LFS format. This is something
we can do more or less unilaterally at this point (AFAIK) but should
still be coordinated with Margo Seltzer.

The amount of work required at that point isn't entirely clear yet.