kern/48474: disk enumeration at boot is off

[htodd%twofifty.com@localhost]

>Number:         48474
>Category:       kern
>Synopsis:       wd1 at boot is wd2 in running kernel
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Dec 23 18:40:00 +0000 2013
>Originator:     Hisashi Todd Fujinaka
>Release:        NetBSD 6.99.28
>Organization:
None
>Environment:
        
        
System: NetBSD mara.i8u.org 6.99.28 NetBSD 6.99.28 (GENERIC) #0: Sun Dec 22 
14:23:09 PST 2013 
htodd%mara.i8u.org@localhost:/usr/obj/amd64-s/sys/arch/amd64/compile/GENERIC 
amd64
Architecture: x86_64
Machine: amd64
>Description:
On boot, I see disks wd0 and wd1. From dmesg:
wd0 at atabus3 drive 0
wd0: <WDC WD5000AAKS-00TMA0>
wd0: drive supports 16-sector PIO transfers, LBA48 addressing
wd0: 465 GB, 969021 cyl, 16 head, 63 sec, 512 bytes/sect x 976773168 sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd0(ahcisata1:0:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133) 
(using DMA)
wd1 at atabus4 drive 0
wd1: <ST3250620AS>
wd1: drive supports 16-sector PIO transfers, LBA48 addressing
wd1: 232 GB, 484521 cyl, 16 head, 63 sec, 512 bytes/sect x 488397168 sectors
wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd1(ahcisata1:1:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133) 
(using DMA)
boot device: wd0
root on wd0a dumps on wd0b

But on the running kernel, trying to access wd1a gives errors:
:~ > sudo mount /dev/wd1a /mnt
mount: cannot open `/dev/wd1a': Device not configured
Exit 1

Turns out that the running kernel thinks it's wd2. This is causing problems 
booting from the "second" disk as well.
/dev/wd2a: file system not clean (fs_clean=0x10); please fsck(8)
/dev/wd2a: lost blocks 0 files 0

        
>How-To-Repeat:
The bootblocks might be wrong; I used NetBSD-6 first and then upgraded this 
disk using build.sh.

But basically, install two disks and reboot the system with NetBSD-6 or 
NetBSD-current.
        
>Fix:
Yes, please.
        

>Unformatted: