SUNRPC: fix NFS client over TCP hangs due to packet loss (Bug 16494)

When reusing a TCP connection, ensure that it's aborted if a previous
shutdown attempt has been made on that connection so that the RPC over
TCP recovery mechanism succeeds.

Signed-off-by: Andy Chittenden <andyc.bluearc@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 22 insertions, 6 deletions

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 7ca65c7005ea..66d136984d57 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1305,10 +1305,11 @@ static void xs_tcp_state_change(struct sock *sk)
         if (!(xprt = xprt_from_sock(sk)))
                 goto out;
         dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
-        dprintk("RPC:       state %x conn %d dead %d zapped %d\n",
+        dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
                         sk->sk_state, xprt_connected(xprt),
                         sock_flag(sk, SOCK_DEAD),
-                        sock_flag(sk, SOCK_ZAPPED));
+                        sock_flag(sk, SOCK_ZAPPED),
+                        sk->sk_shutdown);
 
         switch (sk->sk_state) {
         case TCP_ESTABLISHED:
@@ -1779,10 +1780,25 @@ static void xs_tcp_reuse_connection(struct rpc_xprt *xprt, struct sock_xprt *tra
 {
         unsigned int state = transport->inet->sk_state;
 
-        if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED)
-                return;
-        if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT))
-                return;
+        if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
+                /* we don't need to abort the connection if the socket
+                 * hasn't undergone a shutdown
+                 */
+                if (transport->inet->sk_shutdown == 0)
+                        return;
+                dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
+                                __func__, transport->inet->sk_shutdown);
+        }
+        if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
+                /* we don't need to abort the connection if the socket
+                 * hasn't undergone a shutdown
+                 */
+                if (transport->inet->sk_shutdown == 0)
+                        return;
+                dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
+                                "sk_shutdown set to %d\n",
+                                __func__, transport->inet->sk_shutdown);
+        }
         xs_abort_connection(xprt, transport);
 }