Single slave zone definition for two view (cache file name problem)

[Mark Andrews]

Referencing the same writable file in multiple places in named can:

* lead to corrupted journals
* the wrong zone content being published in the wrong view
* named not being able to serve zone content when restarted when the
  master is down
* content not showing up in a timely manner
* extra zone transfers recovering from the above

If you failed to experience one or more of these you were lucky.
There is a good chance that some of these things were happening and
you were not even aware.

We got bug reports about all of these events that were caused by
the same writable file being referenced multiple times.

Referencing the same writeable file multiple times has never been
a supported configuration.  This is now being caught.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org