[PATCH 3/3] nfsd: skip CB_NULL probes for 4.1 or later

[Christoph Hellwig <hch@lst.de>]

With sessions in v4.1 or later we don't need to manually probe the backchannel
connection, so we can declare it up instantly after setting up the RPC client.

Note that we really should split nfsd4_run_cb_work in the long run, this is
just the least intrusive fix for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/nfsd/nfs4callback.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 4c993aa..5694cfb 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1066,6 +1066,15 @@ nfsd4_run_cb_work(struct work_struct *work)
 			cb->cb_ops->release(cb);
 		return;
 	}
+
+	/*
+	 * Don't send probe messages for 4.1 or later.
+	 */
+	if (!cb->cb_ops && clp->cl_minorversion) {
+		clp->cl_cb_state = NFSD4_CB_UP;
+		return;
+	}
+
 	cb->cb_msg.rpc_cred = clp->cl_cb_cred;
 	rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
 			cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
-- 
1.9.1