bsdlabel, vnode_pager

[grarpamp]

Updated a box from RELENG_7 to RELENG_8 yesterday... make buildworld,
installworld, mergemaster, boot0cfg -Bv ad0, bsdlabel -B ad0s1.

When using bsdlabel I get this from this file:
 src/sys/geom/geom_ctl.c:442: Class not found
this happens I think when bsdlabel refuses to write anything.

So I boot in boot -sv, I get this after it writes to disk:
 vnode_pager_getpages: I/O read error

then even with simple sync I get:
 sync: Input/output error

Although I've got the shell prompt still, any attempt to do anything
fails due to the above. /sbin/reboot doesn't work, requiring
powerdown.  After that things come back fine and I think I'm running
on the new boot0 and slice code. It only wigs out after bsdlabel
is able to write something.

At various times under RELENG_7 I used these two names in bsdlabel,
just like '4.2BSD' is used to mark the partition's usage in bsdlabel.
At some point I reverted them to unused as it seemed to have once
solved the Class issue combined with not being able to edit the
bsdlabel with bsdlabel. ZFS is obvious, unknown was to mark ufs or
raw data slices that should not have any system tools looking inside
it at at any time.

/usr/include/sys/disklabel.h:
#define FS_OTHER        10              /* in use, but unknown/unsupported */
#define FS_ZFS          27              /* Sun's ZFS */
#ifdef  FSTYPENAMES
static const char *fstypenames[] = {
 'unknown'
 'ZFS'

This is currently repeatable with: boot -sv, bsdlabel -B ad0s1.
Hopefully someone else will see it on their box as I'm not really
set up to debug.

Also, I hate CHS addressing, too many chances for operator off by
one, or a dozen :) So whoever was thinking of removing it from
toolsets ala: fdisk, has my full second on that motion :) Though
wasn't there something about beginning/ending on proper boundaries
for full stripe read/writes, performance or configuration or something
like that? How does one know that with only LBA? Or is it superstition?
Thx.

# bsdlabel ad0s1
# /dev/ad0s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  a:   786432        0    4.2BSD        0     0     0
  b:   131072   786432    unused        0     0
  c:  6421905        0    unused        0     0         # "raw" part, don't edit
  d:   262144   917504    unused        0     0
  e:   131072  1179648    unused        0     0
  f:  1310720  1310720    4.2BSD        0     0     0
  g:  3538944  2621440    4.2BSD        0     0     0
  h:   261521  6160384    unused        0     0

# gpart show
=>      63  17803359  ad0  MBR  (8.5G)
        63   6421905    1  freebsd  [active]  (3.1G)
   6421968  11381328    2  freebsd  (5.4G)
  17803296       126       - free -  (63K)

=>      0  6421905  ad0s1  BSD  (3.1G)
        0   786432      1  freebsd-ufs  (384M)
   786432   131072      2  !0  (64M)
   917504   262144      4  !0  (128M)
  1179648   131072      5  !0  (64M)
  1310720  1310720      6  freebsd-ufs  (640M)
  2621440  3538944      7  freebsd-ufs  (1.7G)
  6160384   261521      8  !0  (128M)

# fdisk ad0
******* Working on device /dev/ad0 *******
parameters extracted from in-core disklabel are:
cylinders=17662 heads=16 sectors/track=63 (1008 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=17662 heads=16 sectors/track=63 (1008 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
    start 63, size 6421905 (3135 Meg), flag 80 (active)
        beg: cyl 0/ head 1/ sector 1;
        end: cyl 1023/ head 15/ sector 63
The data for partition 2 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
    start 6421968, size 11381328 (5557 Meg), flag 0
        beg: cyl 1023/ head 255/ sector 63;
        end: cyl 1023/ head 15/ sector 63
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>