SUNRPC: Add a new error code for retry waiting for another binder

Add new error code processing to the kernel's rpcbind client and to
call_bind_status() to distinguish two cases:

Case 1: the remote has replied that the program/version tuple is not
registered (returns -EACCES)

Case 2: another process is already in the middle of binding on this
transport (now returns -EAGAIN)

This change allows more specific retry processing for each of these two
cases.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 7a7cd3b7acce..e53d71827132 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -950,6 +950,12 @@ call_bind_status(struct rpc_task *task)
         }
 
         switch (task->tk_status) {
+        case -EAGAIN:
+                dprintk("RPC: %5u rpcbind waiting for another request "
+                                "to finish\n", task->tk_pid);
+                /* avoid busy-waiting here -- could be a network outage. */
+                rpc_delay(task, 5*HZ);
+                goto retry_timeout;
         case -EACCES:
                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
                                 "unavailable\n", task->tk_pid);