SUNRPC: Allow the client to detect if the TCP connection is closed

Add an xprt->state bit to enable the TCP ->state_change() method to signal
whether or not the TCP connection is in the process of closing down.
This will to be used by the reconnection logic in a separate patch.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 22 insertions, 3 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 6f524a9e7fd0..afb9e6ad7fe0 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -257,6 +257,7 @@ void			xprt_force_disconnect(struct rpc_xprt *xprt);
 #define XPRT_CLOSE_WAIT         (3)
 #define XPRT_BOUND              (4)
 #define XPRT_BINDING            (5)
+#define XPRT_CLOSING            (6)
 
 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 {
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index b5544514ee57..721c5419765e 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -758,7 +758,9 @@ static void xs_close(struct rpc_xprt *xprt)
         sock_release(sock);
 clear_close_wait:
         smp_mb__before_clear_bit();
+        clear_bit(XPRT_CONNECTED, &xprt->state);
         clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
+        clear_bit(XPRT_CLOSING, &xprt->state);
         smp_mb__after_clear_bit();
 }
 
@@ -1118,12 +1120,28 @@ static void xs_tcp_state_change(struct sock *sk)
                 }
                 spin_unlock_bh(&xprt->transport_lock);
                 break;
-        case TCP_SYN_SENT:
-        case TCP_SYN_RECV:
+        case TCP_FIN_WAIT1:
+                /* The client initiated a shutdown of the socket */
+                set_bit(XPRT_CLOSING, &xprt->state);
+                smp_mb__before_clear_bit();
+                clear_bit(XPRT_CONNECTED, &xprt->state);
+                smp_mb__after_clear_bit();
                 break;
         case TCP_CLOSE_WAIT:
+                /* The server initiated a shutdown of the socket */
+                set_bit(XPRT_CLOSING, &xprt->state);
                 xprt_force_disconnect(xprt);
-        default:
+                break;
+        case TCP_LAST_ACK:
+                smp_mb__before_clear_bit();
+                clear_bit(XPRT_CONNECTED, &xprt->state);
+                smp_mb__after_clear_bit();
+                break;
+        case TCP_CLOSE:
+                smp_mb__before_clear_bit();
+                clear_bit(XPRT_CLOSING, &xprt->state);
+                smp_mb__after_clear_bit();
+                /* Mark transport as closed and wake up all pending tasks */
                 xprt_disconnect(xprt);
         }
  out: