Introduced by commit 16b374ca "NFSv4.1: pnfs: filelayout: add driver's
LAYOUTGET and GETDEVICEINFO infrastructure" (October 20, 2010).
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>