nfsd4: keep per-session list of connections

The spec requires us in various places to keep track of the connections
associated with each session.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 07e40c6..79b15fb 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -61,6 +61,9 @@
 #define NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL	0x10000
 #define NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED		0x20000
 
+#define NFS4_CDFC4_FORE	0x1
+#define NFS4_CDFC4_BACK 0x2
+
 #define NFS4_SET_TO_SERVER_TIME	0
 #define NFS4_SET_TO_CLIENT_TIME	1