SUNRPC: Retry bad rpcbind replies

When a server returns a bad rpcbind reply, make rpcbind client recovery logic
retry with an older protocol version.  Older versions are more likely to work
correctly.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index 34738c5cf312..a0c9f6905517 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -446,6 +446,10 @@ static void rpcb_getport_done(struct rpc_task *child, void *data)
         struct rpc_xprt *xprt = map->r_xprt;
         int status = child->tk_status;
 
+        /* Garbage reply: retry with a lesser rpcbind version */
+        if (status == -EIO)
+                status = -EPROTONOSUPPORT;
+
         /* rpcbind server doesn't support this rpcbind protocol version */
         if (status == -EPROTONOSUPPORT)
                 xprt->bind_index++;