vfs-level quota cleanup

[David Holland <dholland-tech%netbsd.org@localhost>]

As promised, draft patches for vfs-level quota cleanup are here:

   http://www.netbsd.org/~dholland/tmp/quota/

It is a 53-part patch series, or if you prefer:

   http://www.netbsd.org/~dholland/tmp/quota/concatenated
   http://www.netbsd.org/~dholland/tmp/quota/onediff

contain the whole thing concatenated, or as a single start-to-end
diff, respectively. The single diff isn't all that straightforward to
follow, but it's less than half the size.

The patches change the VFS-level quota interface to use C structures
for data transfer (mostly the same struct quotakey/quotaval as used by
the userland libquota API) instead of proplib. Anyone still wondering
if this is a good idea should examine patch C-51, which updates the
COMPAT_50 code for the historic quotactl() to call the new interface
instead of the proplib interface. The new code is half the size of the
old code, much clearer, and has many fewer error paths... much like
everywhere else, but in this particular patch the effects are
localized and easily observed.

The interface is defined in <sys/quotactl.h> and is meant to be
extended to also be the user-to-kernel interface; this will involve
removing the interpreter code for quota proplib RPC packets (which is
now all centralized in vfs_quotactl.c) and replacing it with simple
conventional copyin code for struct quotactl_args. I don't have
patches for this yet, and there's additional userland cleanup that
needs to be done first. What you see here is itself hot off the
presses.

These patches are untested; or more accurately, they've been tested as
far as discovering a lethal bug, probably bad proplib refcounting, in
patch C-09. The patches after that might or might not work. They do
compile though and unless some very major surprise appears in testing
(unlikely) the code is in approximately its final form.

So if in the course of reading the diffs you should happen to notice
something screwed up, please let me know.

In order to avoid holding up netbsd-6 I intend to commit this as soon
as I can get patches C-09 through C-53 debugged, which will probably
not be before next weekend and had better not be much after next
weekend. If you object violently, please speak up ASAP. (On the other
hand, if you're just going to rant about how I'm on an anti-proplib
jihad, please spare us. That is hardly the case and you know it.)

One final note: quota2_handle_cmd_cursorget() is now kind of a mess. I
intend to tidy it up once I have it running in approximately its
current form, but I don't want to launch into that until I *do* have
it running, just in case that itself requires substantial editing.

-- 
David A. Holland
dholland%netbsd.org@localhost