1 files changed, 136 insertions, 7 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 5abab094441f..5bc2f45bddf0 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -36,7 +36,9 @@
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/rpc_pipe_fs.h>
 #include <linux/sunrpc/metrics.h>
+#include <linux/sunrpc/bc_xprt.h>
 
+#include "sunrpc.h"
 
 #ifdef RPC_DEBUG
 # define RPCDBG_FACILITY	RPCDBG_CALL
@@ -63,6 +65,9 @@ static void	call_decode(struct rpc_task *task);
 static void	call_bind(struct rpc_task *task);
 static void	call_bind_status(struct rpc_task *task);
 static void	call_transmit(struct rpc_task *task);
+#if defined(CONFIG_NFS_V4_1)
+static void	call_bc_transmit(struct rpc_task *task);
+#endif /* CONFIG_NFS_V4_1 */
 static void	call_status(struct rpc_task *task);
 static void	call_transmit_status(struct rpc_task *task);
 static void	call_refresh(struct rpc_task *task);
@@ -613,6 +618,50 @@ rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 }
 EXPORT_SYMBOL_GPL(rpc_call_async);
 
+#if defined(CONFIG_NFS_V4_1)
+/**
+ * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
+ * rpc_execute against it
+ * @ops: RPC call ops
+ */
+struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
+					const struct rpc_call_ops *tk_ops)
+{
+	struct rpc_task *task;
+	struct xdr_buf *xbufp = &req->rq_snd_buf;
+	struct rpc_task_setup task_setup_data = {
+		.callback_ops = tk_ops,
+	};
+
+	dprintk("RPC: rpc_run_bc_task req= %p\n", req);
+	/*
+	 * Create an rpc_task to send the data
+	 */
+	task = rpc_new_task(&task_setup_data);
+	if (!task) {
+		xprt_free_bc_request(req);
+		goto out;
+	}
+	task->tk_rqstp = req;
+
+	/*
+	 * Set up the xdr_buf length.
+	 * This also indicates that the buffer is XDR encoded already.
+	 */
+	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
+			xbufp->tail[0].iov_len;
+
+	task->tk_action = call_bc_transmit;
+	atomic_inc(&task->tk_count);
+	BUG_ON(atomic_read(&task->tk_count) != 2);
+	rpc_execute(task);
+
+out:
+	dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
+	return task;
+}
+#endif /* CONFIG_NFS_V4_1 */
+
 void
 rpc_call_start(struct rpc_task *task)
 {
@@ -695,6 +744,19 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 
 /*
+ * Restart an (async) RPC call from the call_prepare state.
+ * Usually called from within the exit handler.
+ */
+void
+rpc_restart_call_prepare(struct rpc_task *task)
+{
+	if (RPC_ASSASSINATED(task))
+		return;
+	task->tk_action = rpc_prepare_task;
+}
+EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
+
+/*
  * Restart an (async) RPC call. Usually called from within the
  * exit handler.
  */
@@ -1085,7 +1147,7 @@ call_transmit(struct rpc_task *task)
 	 * in order to allow access to the socket to other RPC requests.
 	 */
 	call_transmit_status(task);
-	if (task->tk_msg.rpc_proc->p_decode != NULL)
+	if (rpc_reply_expected(task))
 		return;
 	task->tk_action = rpc_exit_task;
 	rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
@@ -1120,6 +1182,72 @@ call_transmit_status(struct rpc_task *task)
 	}
 }
 
+#if defined(CONFIG_NFS_V4_1)
+/*
+ * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
+ * addition, disconnect on connectivity errors.
+ */
+static void
+call_bc_transmit(struct rpc_task *task)
+{
+	struct rpc_rqst *req = task->tk_rqstp;
+
+	BUG_ON(task->tk_status != 0);
+	task->tk_status = xprt_prepare_transmit(task);
+	if (task->tk_status == -EAGAIN) {
+		/*
+		 * Could not reserve the transport. Try again after the
+		 * transport is released.
+		 */
+		task->tk_status = 0;
+		task->tk_action = call_bc_transmit;
+		return;
+	}
+
+	task->tk_action = rpc_exit_task;
+	if (task->tk_status < 0) {
+		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
+			"error: %d\n", task->tk_status);
+		return;
+	}
+
+	xprt_transmit(task);
+	xprt_end_transmit(task);
+	dprint_status(task);
+	switch (task->tk_status) {
+	case 0:
+		/* Success */
+		break;
+	case -EHOSTDOWN:
+	case -EHOSTUNREACH:
+	case -ENETUNREACH:
+	case -ETIMEDOUT:
+		/*
+		 * Problem reaching the server.  Disconnect and let the
+		 * forechannel reestablish the connection.  The server will
+		 * have to retransmit the backchannel request and we'll
+		 * reprocess it.  Since these ops are idempotent, there's no
+		 * need to cache our reply at this time.
+		 */
+		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
+			"error: %d\n", task->tk_status);
+		xprt_conditional_disconnect(task->tk_xprt,
+			req->rq_connect_cookie);
+		break;
+	default:
+		/*
+		 * We were unable to reply and will have to drop the
+		 * request.  The server should reconnect and retransmit.
+		 */
+		BUG_ON(task->tk_status == -EAGAIN);
+		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
+			"error: %d\n", task->tk_status);
+		break;
+	}
+	rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
+}
+#endif /* CONFIG_NFS_V4_1 */
+
 /*
  * 6.	Sort out the RPC call status
  */
@@ -1130,8 +1258,8 @@ call_status(struct rpc_task *task)
 	struct rpc_rqst	*req = task->tk_rqstp;
 	int		status;
 
-	if (req->rq_received > 0 && !req->rq_bytes_sent)
-		task->tk_status = req->rq_received;
+	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
+		task->tk_status = req->rq_reply_bytes_recvd;
 
 	dprint_status(task);
 
@@ -1248,7 +1376,7 @@ call_decode(struct rpc_task *task)
 
 	/*
 	 * Ensure that we see all writes made by xprt_complete_rqst()
-	 * before it changed req->rq_received.
+	 * before it changed req->rq_reply_bytes_recvd.
 	 */
 	smp_rmb();
 	req->rq_rcv_buf.len = req->rq_private_buf.len;
@@ -1289,7 +1417,7 @@ out_retry:
 	task->tk_status = 0;
 	/* Note: rpc_verify_header() may have freed the RPC slot */
 	if (task->tk_rqstp == req) {
-		req->rq_received = req->rq_rcv_buf.len = 0;
+		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
 		if (task->tk_client->cl_discrtry)
 			xprt_conditional_disconnect(task->tk_xprt,
 					req->rq_connect_cookie);
@@ -1377,13 +1505,14 @@ rpc_verify_header(struct rpc_task *task)
 	}
 	if ((len -= 3) < 0)
 		goto out_overflow;
-	p += 1;	/* skip XID */
 
+	p += 1; /* skip XID */
 	if ((n = ntohl(*p++)) != RPC_REPLY) {
 		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
-				task->tk_pid, __func__, n);
+			task->tk_pid, __func__, n);
 		goto out_garbage;
 	}
+
 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
 		if (--len < 0)
 			goto out_overflow;