SUNRPC: Fix the problem of EADDRNOTAVAIL syslog floods on reconnect

See http://bugzilla.kernel.org/show_bug.cgi?id=13034

If the port gets into a TIME_WAIT state, then we cannot reconnect without
binding to a new port.

Tested-by: Petr Vandrovec <petr@vandrovec.name>
Tested-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 5 deletions

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index d40ff50887aa..e18596146013 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -807,6 +807,9 @@ static void xs_reset_transport(struct sock_xprt *transport)
  *
  * This is used when all requests are complete; ie, no DRC state remains
  * on the server we want to save.
+ *
+ * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
+ * xs_reset_transport() zeroing the socket from underneath a writer.
  */
 static void xs_close(struct rpc_xprt *xprt)
 {
@@ -824,6 +827,14 @@ static void xs_close(struct rpc_xprt *xprt)
         xprt_disconnect_done(xprt);
 }
 
+static void xs_tcp_close(struct rpc_xprt *xprt)
+{
+        if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
+                xs_close(xprt);
+        else
+                xs_tcp_shutdown(xprt);
+}
+
 /**
  * xs_destroy - prepare to shutdown a transport
  * @xprt: doomed transport
@@ -1772,6 +1783,15 @@ static void xs_tcp_setup_socket(struct rpc_xprt *xprt,
                         xprt, -status, xprt_connected(xprt),
                         sock->sk->sk_state);
         switch (status) {
+        default:
+                printk("%s: connect returned unhandled error %d\n",
+                        __func__, status);
+        case -EADDRNOTAVAIL:
+                /* We're probably in TIME_WAIT. Get rid of existing socket,
+                 * and retry
+                 */
+                set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
+                xprt_force_disconnect(xprt);
         case -ECONNREFUSED:
         case -ECONNRESET:
         case -ENETUNREACH:
@@ -1782,10 +1802,6 @@ static void xs_tcp_setup_socket(struct rpc_xprt *xprt,
                 xprt_clear_connecting(xprt);
                 return;
         }
-        /* get rid of existing socket, and retry */
-        xs_tcp_shutdown(xprt);
-        printk("%s: connect returned unhandled error %d\n",
-                        __func__, status);
 out_eagain:
         status = -EAGAIN;
 out:
@@ -1994,7 +2010,7 @@ static struct rpc_xprt_ops xs_tcp_ops = {
         .buf_free               = rpc_free,
         .send_request           = xs_tcp_send_request,
         .set_retrans_timeout    = xprt_set_retrans_timeout_def,
-        .close                  = xs_tcp_shutdown,
+        .close                  = xs_tcp_close,
         .destroy                = xs_destroy,
         .print_stats            = xs_tcp_print_stats,
 };