Re: More than 16 partitions

On Sat, Apr 25, 2020 at 2:41 PM Theo de Raadt <deraadt@openbsd.org> wrote:
>
> Amelia A Lewis <amyzing@talsever.com> wrote:
>
> > So, and I recognize that the answer might reasonably be "go read more
> > code and figure it out yourself," a question for Theo and others if you
> > have a moment: why couldn't an arch expand past sixteen? It seems, both
> > from the math calculating struct size (which may be mistaken, in which
> > case I apologize) and in the comment for MAXMAXPARTITIONS that more
> > *are* possible.
>
> Because there is another reason. Here are the device nodes for
> two sequentially-numbered disks.
>
> brw-r----- 1 root operator 4, 0 Apr 17 11:50 sd0a
> brw-r----- 1 root operator 4, 1 Apr 17 11:50 sd0b
> brw-r----- 1 root operator 4, 2 Apr 17 11:50 sd0c
> brw-r----- 1 root operator 4, 3 Apr 17 11:50 sd0d
> brw-r----- 1 root operator 4, 4 Apr 17 11:50 sd0e
> brw-r----- 1 root operator 4, 5 Apr 17 11:50 sd0f
> brw-r----- 1 root operator 4, 6 Apr 17 11:50 sd0g
> brw-r----- 1 root operator 4, 7 Apr 17 11:50 sd0h
> brw-r----- 1 root operator 4, 8 Apr 17 11:50 sd0i
> brw-r----- 1 root operator 4, 9 Apr 17 11:50 sd0j
> brw-r----- 1 root operator 4, 10 Apr 17 11:50 sd0k
> brw-r----- 1 root operator 4, 11 Apr 17 11:50 sd0l
> brw-r----- 1 root operator 4, 12 Apr 17 11:50 sd0m
> brw-r----- 1 root operator 4, 13 Apr 17 11:50 sd0n
> brw-r----- 1 root operator 4, 14 Apr 17 11:50 sd0o
> brw-r----- 1 root operator 4, 15 Apr 17 11:50 sd0p
> brw-r----- 1 root operator 4, 16 Apr 17 11:50 sd1a
> brw-r----- 1 root operator 4, 17 Apr 17 11:50 sd1b
> brw-r----- 1 root operator 4, 18 Apr 17 11:50 sd1c
> brw-r----- 1 root operator 4, 19 Apr 17 11:50 sd1d
> brw-r----- 1 root operator 4, 20 Apr 17 11:50 sd1e
> brw-r----- 1 root operator 4, 21 Apr 17 11:50 sd1f
> brw-r----- 1 root operator 4, 22 Apr 17 11:50 sd1g
> brw-r----- 1 root operator 4, 23 Apr 17 11:50 sd1h
> brw-r----- 1 root operator 4, 24 Apr 17 11:50 sd1i
> brw-r----- 1 root operator 4, 25 Apr 17 11:50 sd1j
> brw-r----- 1 root operator 4, 26 Apr 17 11:50 sd1k
> brw-r----- 1 root operator 4, 27 Apr 17 11:50 sd1l
> brw-r----- 1 root operator 4, 28 Apr 17 11:50 sd1m
> brw-r----- 1 root operator 4, 29 Apr 17 11:50 sd1n
> brw-r----- 1 root operator 4, 30 Apr 17 11:50 sd1o
> brw-r----- 1 root operator 4, 31 Apr 17 11:50 sd1p
>
> Look very carefully at this column ^^
>

Are they allocated in the kernel in a linear fashion? If not, you
could allocate additional nodes under a spare major for the extra
partitions. If so, well I'm just talking out of my arse.

I'd see for myself if I could find where they're allocated. I'll have
more of a deep dive later.


--
Aaron Mason - Programmer, open source addict
I've taken my software vows - for beta or for worse