1 files changed, 29 insertions, 7 deletions

diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index 24db2b4d12d3..172935b046de 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -469,6 +469,28 @@ static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbi
         return rpc_run_task(&task_setup_data);
 }
 
+/*
+ * In the case where rpc clients have been cloned, we want to make
+ * sure that we use the program number/version etc of the actual
+ * owner of the xprt. To do so, we walk back up the tree of parents
+ * to find whoever created the transport and/or whoever has the
+ * autobind flag set.
+ */
+static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
+{
+        struct rpc_clnt *parent = clnt->cl_parent;
+
+        while (parent != clnt) {
+                if (parent->cl_xprt != clnt->cl_xprt)
+                        break;
+                if (clnt->cl_autobind)
+                        break;
+                clnt = parent;
+                parent = parent->cl_parent;
+        }
+        return clnt;
+}
+
 /**
  * rpcb_getport_async - obtain the port for a given RPC service on a given host
  * @task: task that is waiting for portmapper request
@@ -478,10 +500,10 @@ static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbi
  */
 void rpcb_getport_async(struct rpc_task *task)
 {
-        struct rpc_clnt *clnt = task->tk_client;
+        struct rpc_clnt *clnt;
         struct rpc_procinfo *proc;
         u32 bind_version;
-        struct rpc_xprt *xprt = task->tk_xprt;
+        struct rpc_xprt *xprt;
         struct rpc_clnt *rpcb_clnt;
         static struct rpcbind_args *map;
         struct rpc_task *child;
@@ -490,13 +512,13 @@ void rpcb_getport_async(struct rpc_task *task)
         size_t salen;
         int status;
 
+        clnt = rpcb_find_transport_owner(task->tk_client);
+        xprt = clnt->cl_xprt;
+
         dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
                 task->tk_pid, __func__,
                 clnt->cl_server, clnt->cl_prog, clnt->cl_vers, xprt->prot);
 
-        /* Autobind on cloned rpc clients is discouraged */
-        BUG_ON(clnt->cl_parent != clnt);
-
         /* Put self on the wait queue to ensure we get notified if
          * some other task is already attempting to bind the port */
         rpc_sleep_on(&xprt->binding, task, NULL);
@@ -578,9 +600,9 @@ void rpcb_getport_async(struct rpc_task *task)
                         task->tk_pid, __func__);
                 return;
         }
-        rpc_put_task(child);
 
-        task->tk_xprt->stat.bind_count++;
+        xprt->stat.bind_count++;
+        rpc_put_task(child);
         return;
 
 bailout_nofree: