[RFC] Reinstate NFS exportability for JFFS2.

[Neil Brown]

On Saturday August 2, bfields at fieldses.org wrote:
> 
> Though really I can't see any great objection to just moving xfs's hack
> up into nfsd.  It may not do everything, but it seems like an
> incremental improvement.

Because it is a hack, and hacks have a tendency to hide deeper
problems, and not be ever get cleaned up and generally to become a
burden to future generations.

However if you do go down that path, can I suggest:

 1/ get rid of the word "hack" throughout the code.  If you think it
    is sensible, make it appear sensible.
 2/ drop the "retry malloc of a smaller size" thing. 
    In fact, you can probably use one of the set of pages that has
    been reserved for the request.  It is very rare that a readdir
    request will be as big as the largest read.
 3/ Make the new way unconditional.  That gives it broader test
    coverage which can only be a good thing.  And what is good for the
    goose is good for the gander... (not that I'm calling anyone a
    goose).


But I still prefer the O_READDIRPLUS approach.

NeilBrown