NFSv4: The NFSv4.0 client must send RENEW calls if it holds a delegation

RFC3530 states that if the client holds a delegation, then it is obliged
to continue to send RENEW calls once every lease period in order to allow
the server to return NFS4ERR_CB_PATH_DOWN if the callback path is
unreachable.

This is not required for NFSv4.1, since the server can at any time set
the SEQ4_STATUS_CB_PATH_DOWN_SESSION in any SEQUENCE operation.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 58adfb6..e1b6607 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -56,6 +56,9 @@
 	NFS4_SESSION_DRAINING,
 };
 
+#define NFS4_RENEW_TIMEOUT		0x01
+#define NFS4_RENEW_DELEGATION_CB	0x02
+
 struct nfs4_minor_version_ops {
 	u32	minor_version;
 
@@ -225,7 +228,7 @@
 };
 
 struct nfs4_state_maintenance_ops {
-	int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *);
+	int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *, unsigned);
 	struct rpc_cred * (*get_state_renewal_cred_locked)(struct nfs_client *);
 	int (*renew_lease)(struct nfs_client *, struct rpc_cred *);
 };