NFSv4: Fail the truncate() if the lock/open stateid is invalid

If the open stateid could not be recovered, or the file locks were lost,
then we should fail the truncate() operation altogether.

Reported-by: Andy Adamson <andros@netapp.com>
Link: http://lkml.kernel.org/r/1393954269-3974-1-git-send-email-andros@netapp.com


Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>