access LVM logical volume as disk?

[Jeff Rizzo <riz%tastylime.net@localhost>]

I feel like I've definitely done this before, but the obvious strategies 
(vnd)
are failing me here:


Is there any way to get NetBSD 10.1 to treat an LVM logical volume as if 
it's
a disk?  Specifically, I can access the gpt on the raw device of the lv
directly, and it shows:

# gpt show /dev/mapper/rvg0-ubnt
      start       size  index  contents
          0          1         PMBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34       2014         Unused
       2048       2048      1  GPT part - BIOS Boot
       4096    4194304      2  GPT part - Linux data
    4198400  205514752      3  GPT part - Linux data
  209713152       2015         Unused
  209715167         32         Sec GPT table
  209715199          1         Sec GPT header

... but now I need to access one or more of the partitions.  I thought,
"I know, I'll just put a vnd on it", but that doesn't work:

# vnconfig -c vnd0 /dev/mapper/rvg0-ubnt
vnconfig: /dev/rvnd0: VNDIOCSET: Operation not supported

Just in case, I tried the block device:
# vnconfig -c vnd0 /dev/mapper/vg0-ubnt
vnconfig: /dev/rvnd0: VNDIOCSET: Operation not supported

... is there any way to do this short of dumping the entire device (or
section thereof) to a file and THEN using vnconfig?  This seems like it
should be easier.  :) :) :)


Thanks,

+j