kern/49136: wedge support breaks ccd using traditional device-path component names

[jdbaker%mylinuxisp.com@localhost]

>Number:         49136
>Category:       kern
>Synopsis:       wedge support breaks ccd using traditional device-path 
>component names
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Aug 21 15:55:00 +0000 2014
>Originator:     John D. Baker
>Release:        NetBSD/i386-7.99.1 after 18-Aug-2014 06:32 UTC
>Organization:
>Environment:
NetBSD faye 7.99.1 NetBSD 7.99.1 (FAYE) #1: Wed Aug 20 23:01:47 CDT 2014  
sysop%verthandi.technoskunk.fur@localhost:/d0/build/current/obj/i386/sys/arch/i386/compile/FAYE
 i386

>Description:
Following the enabling of MBR/disklabel wedge support, "ccd" devices
configured with traditional device-path component names fail:

#
# /etc/ccd.conf
# Configuration file for concatenated disk devices
#

# ccd           ileave  flags   component devices
ccd0            32      none    /dev/wd0p /dev/wd1p

and subsequent attempts to access (such as the boot-time fsck)
report "device not configured" and eventually an unexpected
inconsistency causing multiuser boot to be aborted.
>How-To-Repeat:
On a system with a "ccd" device configured using traditional device
paths similar to that shown above, boot a kernel that has MBR/disklabel
wedge support enabled.
>Fix:
At this time, changing the components to "/dev/dkN" (as found in
'dmesg' output) appears to be the only way to achieve working "ccd"
devices:

#
# /etc/ccd.conf
# Configuration file for concatenated disk devices
#

# ccd           ileave  flags   component devices
ccd0            32      none    /dev/dk6 /dev/dk7

Interestingly, once configured, partitions on the "ccd" device are not
then associated with any "/dev/dkN" wedge devices.

It would be nice to have the old device names continue to work, and for
'ccdconfig' to grow "NAME=..." support.