[OpenAFS] Re: [OpenAFS-devel] interface for vos split

Thomas Kula kula@tproa.net
Thu, 8 Jan 2009 15:46:55 -0500

On Thu, Jan 08, 2009 at 12:32:20PM -0800, Russ Allbery wrote:
> "Steven Jenkins" <steven.jenkins@gmail.com> writes:
> > Thus it seems to me most straightforward from a user-experience
> > viewpoint to require the vnode.  and not provide a -dirname option, but
> > make sure the man page shows how to use fs gettfid to determine the
> > vnode.  The user experience would not necessarily be ideal, but it would
> > be consistent, thus less frustrating to the user in the long run.
> I think this is a better tradeoff than adding a new volserver call,
> definitely.  If we can't put the capability of fs getfid into vos, I think
> the above would be less confusing than an implementation that sort of
> supports directory names but doesn't in a way that users expect.

I think the -dirvnode option should be included no matter
which way this goes. The man page should provide instructions
on finding the directory vnode, with the comment that, of
course, you'll have to run it on a machine with a running
cache manager.

If it is sane (and I'm loath to use the word sane in
connection with the vos command) to include enough bits
to reproduce fs getfid in it, then I think we should
support the -dirname option. This gives us support for
both relative and absolute -dirname (both of which users
are going to expect at some point). I would suggest
that if -dirname is tried and the PIOCTL fails the
error message suggest using the -dirvnode option (while
most of the time I'd probably run this command I'd be
on a machine that has a cache manager, I run vos plenty
of times on machines that do not, and we should catch
that and at least report back something sane). 

I, like many others, would be reluctant to add even more
stuff to the vos command (I agree with Russ that the bulk
of vos should be in a shared library and that it would be
a decent sized task to do that), but to be most useful,
I think adding more stuff in is called for here.

Otherwise, yeah, if pulling enough stuff in to give vos
the ability to determine vnode numbers in both the 
relative and absolute path cases is too much, leave
it out and only provide -dirvnode. 

Thomas L. Kula | kula@tproa.net | http://kula.tproa.net/