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)

1 files changed, 29 insertions, 23 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 4ba271f892c8..d6409e757219 100644
--- 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.
  */