exportfs -d logs 9p traffic to /tmp/exportdb.
-f allows writing to a different file.
exportfs silently continues if it doesn't have
permissions to create or write to /tmp/exportdb.
These are poor behaviors.
A better default is to write to stderr, since it
is 9P debug info that is better immediately printed,
and not user info that is better handled by syslog().
As a result, -f is obsolete and thus removed.
Redirect responsibility is now on rc.
As a side effect, rc will fail if it doesn't
have permissions to write.
exportfs(4) is updated to reflect all changes
and with a better Synopsis.
oexportfs is changed to match exportfs.
oexportfs(4) is updated to reflect all changes.
The Synopsis is not changed due to the number of flags.
Removed -f from iostats.
iostats(4) is updated to reflect all changes.
---
old iostats failed to work when builidng the kernel due to old bugs
that where already fixed in exportfs. instead of backporting the fixes,
reimplement iostats as a filter that sits between exportfs and the
process mount. from users perspective, theres no difference.
the result is much smaller and can handle everything that exportfs
can like /srv.
