ufs: NFS support

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>