SUNRPC: RPC client should retry with different versions of rpcbind

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 16 insertions, 2 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index a42f767dcdd..20bec7767dd 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1734,6 +1734,18 @@ config SUNRPC
 config SUNRPC_GSS
         tristate
 
+config SUNRPC_BIND34
+        bool "Support for rpcbind versions 3 & 4 (EXPERIMENTAL)"
+        depends on SUNRPC && EXPERIMENTAL
+        help
+          Provides kernel support for querying rpcbind servers via versions 3
+          and 4 of the rpcbind protocol.  The kernel automatically falls back
+          to version 2 if a remote rpcbind service does not support versions
+          3 or 4.
+
+          If unsure, say N to get traditional behavior (version 2 rpcbind
+          requests only).
+
 config RPCSEC_GSS_KRB5
         tristate "Secure RPC: Kerberos V mechanism (EXPERIMENTAL)"
         depends on SUNRPC && EXPERIMENTAL
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index e7dc09ecc47..d8fbee40a19 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -902,9 +902,11 @@ call_bind_status(struct rpc_task *task)
                                 task->tk_pid);
                 break;
         case -EPROTONOSUPPORT:
-                dprintk("RPC: %5u remote rpcbind version 2 unavailable\n",
+                dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
                                 task->tk_pid);
-                break;
+                task->tk_status = 0;
+                task->tk_action = call_bind;
+                return;
         default:
                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
                                 task->tk_pid, -task->tk_status);