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>

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 7ca65c7005ea5d2445ddddd617017ab3e6539f29..66d136984d57f1d767d6ddb7189db96e4cf06b2a 100644 (file)
--- 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);
 }