The typical result of the backwards comparison here is that the source
server in a server-to-server copy will return BAD_STATEID within a few
seconds of the copy starting, instead of giving the copy a full lease
period, so the copy_file_range() call will end up unnecessarily
returning a short read.

Fixes: 624322f1 "NFSD add COPY_NOTIFY operation"
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>