Re: [9fans] qids

["rob pike, esq." <rob@mightycheese.com>]

> I am writing a file server to be overlayed on a portion
> of an existing name space.  It presents the original
> name space, plus some new files.
> 
> I'm trying to decide how to manage the qids.  The issue
> is choosing qids for the new files without colliding
> with qids of the old ones.

If your server is a separate mount point that doesn't
itself serve the underlying files, don't worry about it;
the server is part of the uniqueness criteria for the files.

> The best related example I've seen is the qid hash
> table in exportfs.  Is there a better one?

If you are instead serving leftovers like exportfs, then
you'll need to something analogous.  Servers of original
files are encouraged to use only the low 48 bits of the
qid.path to permit encapsulating servers to use the top
16 bits to generate uniqueness.  The code in exportfs
may be a good example, but last I looked it was a bit
obscure.

-rob