NFSv4.1: Fix a request leak on the back channel

If the call to svc_process_common() fails, then the request
needs to be freed before we can exit bc_svc_process.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

net/sunrpc/svc.c

@@ -1377,7 +1377,8 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
 						sizeof(req->rq_snd_buf));
 		return bc_send(req);
 	} else {
-		/* Nothing to do to drop request */
+		/* drop request */
+		xprt_free_bc_request(req);
 		return 0;
 	}
 }