NFSv4.1: Fall back to ordinary i/o through the mds if we have no layout segment

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --cc fs/nfs/internal.h
Simple merge

diff --cc fs/nfs/nfs4filelayout.c
Simple merge

diff --cc fs/nfs/objlayout/objio_osd.c
Simple merge

diff --cc fs/nfs/pnfs.c
Simple merge

diff --cc fs/nfs/read.c
Simple merge

diff --cc fs/nfs/write.c
Simple merge