RPC: Ensure that we disconnect TCP socket when client requests error out

If we're part way through transmitting a TCP request, and the client
errors, then we need to disconnect and reconnect the TCP socket in order to
avoid confusing the server.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 031a50c8b9ea82616abd4a4e18021a25848941ce commit)

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index e8bbe81..840e47a 100644 (file)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -229,7 +229,7 @@ int                 xprt_reserve_xprt(struct rpc_task *task);
 int                    xprt_reserve_xprt_cong(struct rpc_task *task);
 int                    xprt_prepare_transmit(struct rpc_task *task);
 void                   xprt_transmit(struct rpc_task *task);
-void                   xprt_abort_transmit(struct rpc_task *task);
+void                   xprt_end_transmit(struct rpc_task *task);
 int                    xprt_adjust_timeout(struct rpc_rqst *req);
 void                   xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 void                   xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 4ba271f..d6409e7 100644 (file)
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -921,26 +921,43 @@ call_transmit(struct rpc_task *task)
        task->tk_status = xprt_prepare_transmit(task);
        if (task->tk_status != 0)
                return;
+       task->tk_action = call_transmit_status;
        /* Encode here so that rpcsec_gss can use correct sequence number. */
        if (rpc_task_need_encode(task)) {
-               task->tk_rqstp->rq_bytes_sent = 0;
+               BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
                call_encode(task);
                /* Did the encode result in an error condition? */
                if (task->tk_status != 0)
-                       goto out_nosend;
+                       return;
        }
-       task->tk_action = call_transmit_status;
        xprt_transmit(task);
        if (task->tk_status < 0)
                return;
-       if (!task->tk_msg.rpc_proc->p_decode) {
-               task->tk_action = rpc_exit_task;
-               rpc_wake_up_task(task);
-       }
-       return;
-out_nosend:
-       /* release socket write lock before attempting to handle error */
-       xprt_abort_transmit(task);
+       /*
+        * On success, ensure that we call xprt_end_transmit() before sleeping
+        * 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)
+               return;
+       task->tk_action = rpc_exit_task;
+       rpc_wake_up_task(task);
+}
+
+/*
+ * 5a. Handle cleanup after a transmission
+ */
+static void
+call_transmit_status(struct rpc_task *task)
+{
+       task->tk_action = call_status;
+       /*
+        * Special case: if we've been waiting on the socket's write_space()
+        * callback, then don't call xprt_end_transmit().
+        */
+       if (task->tk_status == -EAGAIN)
+               return;
+       xprt_end_transmit(task);
        rpc_task_force_reencode(task);
 }
 
@@ -992,18 +1009,7 @@ call_status(struct rpc_task *task)
 }
 
 /*
- * 6a. Handle transmission errors.
- */
-static void
-call_transmit_status(struct rpc_task *task)
-{
-       if (task->tk_status != -EAGAIN)
-               rpc_task_force_reencode(task);
-       call_status(task);
-}
-
-/*
- * 6b. Handle RPC timeout
+ * 6a. Handle RPC timeout
  *     We do not release the request slot, so we keep using the
  *     same XID for all retransmits.
  */

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 313b68d..e8c2bc4 100644 (file)
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -707,12 +707,9 @@ out_unlock:
        return err;
 }
 
-void
-xprt_abort_transmit(struct rpc_task *task)
+void xprt_end_transmit(struct rpc_task *task)
 {
-       struct rpc_xprt *xprt = task->tk_xprt;
-
-       xprt_release_write(xprt, task);
+       xprt_release_write(task->tk_xprt, task);
 }
 
 /**
@@ -761,8 +758,6 @@ void xprt_transmit(struct rpc_task *task)
                        task->tk_status = -ENOTCONN;
                else if (!req->rq_received)
                        rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
-
-               xprt->ops->release_xprt(xprt, task);
                spin_unlock_bh(&xprt->transport_lock);
                return;
        }
@@ -772,18 +767,8 @@ void xprt_transmit(struct rpc_task *task)
         *       schedq, and being picked up by a parallel run of rpciod().
         */
        task->tk_status = status;
-
-       switch (status) {
-       case -ECONNREFUSED:
+       if (status == -ECONNREFUSED)
                rpc_sleep_on(&xprt->sending, task, NULL, NULL);
-       case -EAGAIN:
-       case -ENOTCONN:
-               return;
-       default:
-               break;
-       }
-       xprt_release_write(xprt, task);
-       return;
 }
 
 static inline void do_xprt_reserve(struct rpc_task *task)

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index ee678ed..441bd53 100644 (file)
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -413,6 +413,33 @@ static int xs_tcp_send_request(struct rpc_task *task)
        return status;
 }
 
+/**
+ * xs_tcp_release_xprt - clean up after a tcp transmission
+ * @xprt: transport
+ * @task: rpc task
+ *
+ * This cleans up if an error causes us to abort the transmission of a request.
+ * In this case, the socket may need to be reset in order to avoid confusing
+ * the server.
+ */
+static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+       struct rpc_rqst *req;
+
+       if (task != xprt->snd_task)
+               return;
+       if (task == NULL)
+               goto out_release;
+       req = task->tk_rqstp;
+       if (req->rq_bytes_sent == 0)
+               goto out_release;
+       if (req->rq_bytes_sent == req->rq_snd_buf.len)
+               goto out_release;
+       set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
+out_release:
+       xprt_release_xprt(xprt, task);
+}
+
 /**
  * xs_close - close a socket
  * @xprt: transport
@@ -1250,7 +1277,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
 
 static struct rpc_xprt_ops xs_tcp_ops = {
        .reserve_xprt           = xprt_reserve_xprt,
-       .release_xprt           = xprt_release_xprt,
+       .release_xprt           = xs_tcp_release_xprt,
        .set_port               = xs_set_port,
        .connect                = xs_connect,
        .buf_alloc              = rpc_malloc,