kern/60456: FFS_NO_SNAPSHOT option is not entirely effective

["thorpej%me.com@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60456
>Category:       kern
>Synopsis:       FFS_NO_SNAPSHOT option is not entirely effective
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jul 17 18:50:00 +0000 2026
>Originator:     Jason Thorpe
>Release:        11.99.7
>Organization:
Retrogrouches R Us
>Environment:
NetBSD icarus 11.99.7 NetBSD 11.99.7 (PHAETHON1) #137: Fri Jul 17 08:56:41 PDT 2026  thorpej@dhcp-105.ktnet:/Users/thorpej/NetBSD/current/src/sys/arch/hb68k/compile/PHAETHON1 hb68k
>Description:
The FFS_NO_SNAPSHOT option exists, yet when it is enabled, I pay for nearly 2 pages of .text on my machine:

dhcp-105:thorpej$ m68k--netbsdelf-size ffs_snapshot.o 
   text	   data	    bss	    dec	    hex	filename
   7713	      0	      0	   7713	   1e21	ffs_snapshot.o
dhcp-105:thorpej$ 

opt_ffs.h:#define	FFS_NO_SNAPSHOT	1

>How-To-Repeat:
Enable FFS_NO_SNAPSHOT, build kernel, observe that ffs_snapshot.o is still built and contains progbits.
>Fix:
Yes please.