SUNRPC: Respond promptly to server TCP resets
If the server sends us an RST error while we're in the TCP_ESTABLISHED
state, then that will not result in a state change, and so the RPC client
ends up hanging forever (see
http://bugzilla.kernel.org/show_bug.cgi?id=11154)
We can intercept the reset by setting up an sk->sk_error_report callback,
which will then allow us to initiate a proper shutdown and retry...
We also make sure that if the send request receives an ECONNRESET, then we
shutdown too...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 9a288d5..0a50361 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -249,6 +249,7 @@
void (*old_data_ready)(struct sock *, int);
void (*old_state_change)(struct sock *);
void (*old_write_space)(struct sock *);
+ void (*old_error_report)(struct sock *);
};
/*
@@ -698,8 +699,9 @@
case -EAGAIN:
xs_nospace(task);
break;
- case -ECONNREFUSED:
case -ECONNRESET:
+ xs_tcp_shutdown(xprt);
+ case -ECONNREFUSED:
case -ENOTCONN:
case -EPIPE:
status = -ENOTCONN;
@@ -742,6 +744,22 @@
xprt_release_xprt(xprt, task);
}
+static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
+{
+ transport->old_data_ready = sk->sk_data_ready;
+ transport->old_state_change = sk->sk_state_change;
+ transport->old_write_space = sk->sk_write_space;
+ transport->old_error_report = sk->sk_error_report;
+}
+
+static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
+{
+ sk->sk_data_ready = transport->old_data_ready;
+ sk->sk_state_change = transport->old_state_change;
+ sk->sk_write_space = transport->old_write_space;
+ sk->sk_error_report = transport->old_error_report;
+}
+
/**
* xs_close - close a socket
* @xprt: transport
@@ -765,9 +783,8 @@
transport->sock = NULL;
sk->sk_user_data = NULL;
- sk->sk_data_ready = transport->old_data_ready;
- sk->sk_state_change = transport->old_state_change;
- sk->sk_write_space = transport->old_write_space;
+
+ xs_restore_old_callbacks(transport, sk);
write_unlock_bh(&sk->sk_callback_lock);
sk->sk_no_check = 0;
@@ -1180,6 +1197,28 @@
}
/**
+ * xs_tcp_error_report - callback mainly for catching RST events
+ * @sk: socket
+ */
+static void xs_tcp_error_report(struct sock *sk)
+{
+ struct rpc_xprt *xprt;
+
+ read_lock(&sk->sk_callback_lock);
+ if (sk->sk_err != ECONNRESET || sk->sk_state != TCP_ESTABLISHED)
+ goto out;
+ if (!(xprt = xprt_from_sock(sk)))
+ goto out;
+ dprintk("RPC: %s client %p...\n"
+ "RPC: error %d\n",
+ __func__, xprt, sk->sk_err);
+
+ xprt_force_disconnect(xprt);
+out:
+ read_unlock(&sk->sk_callback_lock);
+}
+
+/**
* xs_udp_write_space - callback invoked when socket buffer space
* becomes available
* @sk: socket whose state has changed
@@ -1454,10 +1493,9 @@
write_lock_bh(&sk->sk_callback_lock);
+ xs_save_old_callbacks(transport, sk);
+
sk->sk_user_data = xprt;
- transport->old_data_ready = sk->sk_data_ready;
- transport->old_state_change = sk->sk_state_change;
- transport->old_write_space = sk->sk_write_space;
sk->sk_data_ready = xs_udp_data_ready;
sk->sk_write_space = xs_udp_write_space;
sk->sk_no_check = UDP_CSUM_NORCV;
@@ -1589,13 +1627,13 @@
write_lock_bh(&sk->sk_callback_lock);
+ xs_save_old_callbacks(transport, sk);
+
sk->sk_user_data = xprt;
- transport->old_data_ready = sk->sk_data_ready;
- transport->old_state_change = sk->sk_state_change;
- transport->old_write_space = sk->sk_write_space;
sk->sk_data_ready = xs_tcp_data_ready;
sk->sk_state_change = xs_tcp_state_change;
sk->sk_write_space = xs_tcp_write_space;
+ sk->sk_error_report = xs_tcp_error_report;
sk->sk_allocation = GFP_ATOMIC;
/* socket options */
