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>
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@ -249,6 +249,7 @@ struct sock_xprt {
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void (*old_data_ready)(struct sock *, int);
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void (*old_state_change)(struct sock *);
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void (*old_write_space)(struct sock *);
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void (*old_error_report)(struct sock *);
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};
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/*
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@ -698,8 +699,9 @@ static int xs_tcp_send_request(struct rpc_task *task)
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case -EAGAIN:
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xs_nospace(task);
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break;
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case -ECONNREFUSED:
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case -ECONNRESET:
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xs_tcp_shutdown(xprt);
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case -ECONNREFUSED:
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case -ENOTCONN:
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case -EPIPE:
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status = -ENOTCONN;
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@ -742,6 +744,22 @@ out_release:
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xprt_release_xprt(xprt, task);
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}
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static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
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{
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transport->old_data_ready = sk->sk_data_ready;
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transport->old_state_change = sk->sk_state_change;
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transport->old_write_space = sk->sk_write_space;
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transport->old_error_report = sk->sk_error_report;
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}
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static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
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{
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sk->sk_data_ready = transport->old_data_ready;
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sk->sk_state_change = transport->old_state_change;
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sk->sk_write_space = transport->old_write_space;
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sk->sk_error_report = transport->old_error_report;
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}
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/**
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* xs_close - close a socket
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* @xprt: transport
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@ -765,9 +783,8 @@ static void xs_close(struct rpc_xprt *xprt)
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transport->sock = NULL;
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sk->sk_user_data = NULL;
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sk->sk_data_ready = transport->old_data_ready;
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sk->sk_state_change = transport->old_state_change;
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sk->sk_write_space = transport->old_write_space;
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xs_restore_old_callbacks(transport, sk);
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write_unlock_bh(&sk->sk_callback_lock);
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sk->sk_no_check = 0;
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@ -1179,6 +1196,28 @@ static void xs_tcp_state_change(struct sock *sk)
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read_unlock(&sk->sk_callback_lock);
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}
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/**
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* xs_tcp_error_report - callback mainly for catching RST events
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* @sk: socket
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*/
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static void xs_tcp_error_report(struct sock *sk)
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{
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struct rpc_xprt *xprt;
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read_lock(&sk->sk_callback_lock);
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if (sk->sk_err != ECONNRESET || sk->sk_state != TCP_ESTABLISHED)
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goto out;
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if (!(xprt = xprt_from_sock(sk)))
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goto out;
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dprintk("RPC: %s client %p...\n"
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"RPC: error %d\n",
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__func__, xprt, sk->sk_err);
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xprt_force_disconnect(xprt);
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out:
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read_unlock(&sk->sk_callback_lock);
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}
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/**
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* xs_udp_write_space - callback invoked when socket buffer space
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* becomes available
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@ -1454,10 +1493,9 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
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write_lock_bh(&sk->sk_callback_lock);
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xs_save_old_callbacks(transport, sk);
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sk->sk_user_data = xprt;
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transport->old_data_ready = sk->sk_data_ready;
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transport->old_state_change = sk->sk_state_change;
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transport->old_write_space = sk->sk_write_space;
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sk->sk_data_ready = xs_udp_data_ready;
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sk->sk_write_space = xs_udp_write_space;
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sk->sk_no_check = UDP_CSUM_NORCV;
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@ -1589,13 +1627,13 @@ static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
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write_lock_bh(&sk->sk_callback_lock);
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xs_save_old_callbacks(transport, sk);
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sk->sk_user_data = xprt;
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transport->old_data_ready = sk->sk_data_ready;
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transport->old_state_change = sk->sk_state_change;
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transport->old_write_space = sk->sk_write_space;
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sk->sk_data_ready = xs_tcp_data_ready;
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sk->sk_state_change = xs_tcp_state_change;
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sk->sk_write_space = xs_tcp_write_space;
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sk->sk_error_report = xs_tcp_error_report;
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sk->sk_allocation = GFP_ATOMIC;
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/* socket options */
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