[ENBD] nbd-2.4.12 released

[Peter T. Breuer]

"A month of sundays ago Paul Flinders wrote:"
> Look on the bright side the more bugs I find the more get squashed :-)

Before you mention it, I found more bugs in 2.4.* while looking at the
error case scenarios over the weekend.

A killed nbd-client failed to reconnect because it tried to do a short
form of the negotiation while the server it talked to tried to do a
long form. This in turn was because I forgot to implement separate
ports (or alternatively a switchable protocol) for short and long
forms.

I've had to make each server/client cluster go find a port of their
own after the initial connect on the generic ctl port. Reconnects
are to the clusters port and elicit short forms of the negotiation
requiring password and signature only. Talking to the generic ctl
port gets you a whole info interchange suitable for setting up a new
client/server cluster.

It seems to work. Working mode tests are passed and I have tested
killing a slave client daemon. It reconnected fine. I am impressed!
(I had also forgotten to make the servers react to the absence of
a heartbeat, but that's fixed too, and after 30s servers die and
reconnect).

So 2.4.12 is on the ftp site. I'll announce it as soon as the docs are
straight.

   ftp://oboe.it.uc3m.es/pub/Programs/nbd-2.4.12.tgz

I'll examine the 2.2 codes to see if any fixes need to be backed into
them.

Peter