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/nfs4proc.c b/fs/nfs/nfs4proc.c
index b358ec1..e89940a 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3386,7 +3386,7 @@
 	.rpc_release = nfs4_renew_release,
 };
 
-static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred)
+static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
 {
 	struct rpc_message msg = {
 		.rpc_proc	= &nfs4_procedures[NFSPROC4_CLNT_RENEW],
@@ -3395,6 +3395,8 @@
 	};
 	struct nfs4_renewdata *data;
 
+	if (renew_flags == 0)
+		return 0;
 	if (!atomic_inc_not_zero(&clp->cl_count))
 		return -EIO;
 	data = kmalloc(sizeof(*data), GFP_NOFS);
@@ -5504,11 +5506,13 @@
 	return rpc_run_task(&task_setup_data);
 }
 
-static int nfs41_proc_async_sequence(struct nfs_client *clp, struct rpc_cred *cred)
+static int nfs41_proc_async_sequence(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
 {
 	struct rpc_task *task;
 	int ret = 0;
 
+	if ((renew_flags & NFS4_RENEW_TIMEOUT) == 0)
+		return 0;
 	task = _nfs41_proc_sequence(clp, cred);
 	if (IS_ERR(task))
 		ret = PTR_ERR(task);