Re: vnd.c 1.254

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sun, 17 Jan 2016 11:52:42 +0100
    From:        Manuel Bouyer <bouyer%antioche.eu.org@localhost>
    Message-ID:  <20160117105242.GC1498%asim.lip6.fr@localhost>

  | This is how vnconfig -l has been working for a long time.

Not that long, only since vnd was made a cloning device, which means
only in NetBSD 7 (it wasn't cloning in NetBSD 6).   Of course, the
change was sometime in the 6.99.* series.   Before that, vnconfig -l
paid no attention to /dev at all (which is as it should be) and simply
showed the status of every possible vnd device.

When it became cloning, that is obviously impossible, and the hack was
added to use the contents of /dev to decide what it should list.  That
was a mistake, and is what caused the current problems (it worked OK
as long as the correct vnconfig was used, but anyone using a NetBSD 6.99.x
kernel with NetBSD 6 userland would have had a problem).

  | HEAD has been changed, which means that HEAD won't list free devices
  | which exists in /dev. I think this behavior is brocken.

I disagree.  I think it should be changed further to not list any
free devices at all.

  | We are running a vnconfig from netbsd-7.

That would do it.   Update it to what is on the netbsd-7 branch or
the netbsd-7-0 branch.

  | netbsd-7 vnconfig was broken to fix a problem with netbsd-7
  | kernel+netbsd-6 userland. This is inacceptable.

No, it was the right choice, there are (and particularly were) far more
people running NetBSD 6 than NetBSD 7.   What's more, NetBSD 7 has had a
lot of bug fixes pulled up, there really should be a 7.0.1 release
very soon, and the current 7.0 should be forgotten.

  | In addition it seems that in some case, vnconfig fails to configure
  | a free device.

If that is happening we need to find out why.   Can you add some debug to
the script to figure out what error is occurring (perhaps removing the
redirect to /dev/null on the vnconfig).

kre