Allow the client to inform the MDS of statistics

Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
Allow the client to inform the MDS of statistics

Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
Merge branch 'layouts' of github.com:loghyr/NFSv4.2 into layouts
Morph LAYOUTRETURN errors into LAYOUTERROR

Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
Reorder the ops, minor typos

Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
Answer Christoph's question about opcodes