nfsd41: add flag checking for create_session

Teach the NFS server to reject invalid create_session flags.

Also do some minor formatting adjustments.

Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fbde6f7..6dbaa37 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1515,6 +1515,9 @@
 	bool confirm_me = false;
 	int status = 0;
 
+	if (cr_ses->flags & ~SESSION4_FLAG_MASK_A)
+		return nfserr_inval;
+
 	nfs4_lock_state();
 	unconf = find_unconfirmed_client(&cr_ses->clientid);
 	conf = find_confirmed_client(&cr_ses->clientid);