From a1aea8fc3977ffa9951c3d7f27dbb1905e5f560f Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 7 Nov 2011 15:00:17 +1100
Subject: [PATCH] sunrpc: wake up SOFTCONN tasks when a connection error
 happens.
Patch-mainline: submitted
References: bnc#679059

A 'SOFTCONN' task should fail if there is an error or a major timeout
during connection.

However errors are currently converted into a timeout (60seconds for
TCP) which is treated as a minor timeout and 3 of these are required
before failure.

The result of this is that if you try to mount an NFSv4 filesystem
(which doesn't require rpcbind and the failure modes that provides)
from a server which you do not have a route to (an so get
NETUNREACHABLE), you have an unnecessary 3 minutes timeout.

So when ENETUNREACH is reported for a connection - or other errors
which are fatal, wake up any SOFTCONN tasks with that error - rather
than letting them wait 60 seconds and then generate ETIMEDOUT.

This causes the above mentioned mount attempt to fail instantly.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: NeilBrown <neilb@suse.de>

---
 include/linux/sunrpc/sched.h |    1 +
 net/sunrpc/sched.c           |   29 +++++++++++++++++++++++++++++
 net/sunrpc/xprtsock.c        |    6 +++++-
 3 files changed, 35 insertions(+), 1 deletions(-)

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index e775689..b85451b 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -236,6 +236,7 @@ void		rpc_wake_up_queued_task(struct rpc_wait_queue *,
					bool (*)(struct rpc_task *, void *),
					void *);
 void		rpc_wake_up_status(struct rpc_wait_queue *, int);
+void		rpc_wake_up_softconn_status(struct rpc_wait_queue *, int);
 int		rpc_queue_empty(struct rpc_wait_queue *);
 void		rpc_delay(struct rpc_task *, unsigned long);
 void *		rpc_malloc(struct rpc_task *, size_t);
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index d12ffa5..d92000a 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -543,6 +543,35 @@ void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
 }
 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
 
+/**
+ * rpc_wake_up_softconn_status - wake up all SOFTCONN rpc_tasks and set their
+ * status value.
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ * @status: status value to set
+ *
+ * Grabs queue->lock
+ */
+void rpc_wake_up_softconn_status(struct rpc_wait_queue *queue, int status)
+{
+	struct rpc_task *task, *next;
+	struct list_head *head;
+
+	spin_lock_bh(&queue->lock);
+	head = &queue->tasks[queue->maxpriority];
+	for (;;) {
+		list_for_each_entry_safe(task, next, head, u.tk_wait.list)
+			if (RPC_IS_SOFTCONN(task)) {
+				task->tk_status = status;
+				rpc_wake_up_task_queue_locked(queue, task);
+			}
+		if (head == &queue->tasks[0])
+			break;
+		head--;
+	}
+	spin_unlock_bh(&queue->lock);
+}
+EXPORT_SYMBOL_GPL(rpc_wake_up_softconn_status);
+
 static void __rpc_queue_timer_fn(unsigned long ptr)
 {
 	struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index d7f97ef..02c683b 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2158,7 +2158,11 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 	case -ECONNREFUSED:
 	case -ECONNRESET:
 	case -ENETUNREACH:
-		/* retry with existing socket, after a delay */
+		/* Retry with existing socket after a delay, except
+		 * for SOFTCONN tasks which fail. */
+		xprt_clear_connecting(xprt);
+		rpc_wake_up_softconn_status(&xprt->pending, status);
+		return;
 	case 0:
 	case -EINPROGRESS:
 	case -EALREADY:
-- 
1.7.7