From 7d1e8255cf959fba7ee2317550dfde39f0b936ae Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 11 Mar 2009 14:38:03 -0400 Subject: [PATCH] SUNRPC: Add the equivalent of the linger and linger2 timeouts to RPC sockets This fixes a regression against FreeBSD servers as reported by Tomas Kasparek. Apparently when using RPC over a TCP socket, the FreeBSD servers don't ever react to the client closing the socket, and so commit e06799f958bf7f9f8fae15f0c6f519953fb0257c (SUNRPC: Use shutdown() instead of close() when disconnecting a TCP socket) causes the setup to hang forever whenever the client attempts to close and then reconnect. We break the deadlock by adding a 'linger2' style timeout to the socket, after which, the client will abort the connection using a TCP 'RST'. The default timeout is set to 15 seconds. A subsequent patch will put it under user control by means of a systctl. Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/xprtsock.c | 98 ++++++++++++++++++++++++++++++------- 2 files changed, 82 insertions(+), 17 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 2b0d960603b9..1758d9f5b5c3 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -260,6 +260,7 @@ void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie); #define XPRT_BOUND (4) #define XPRT_BINDING (5) #define XPRT_CLOSING (6) +#define XPRT_CONNECTION_ABORT (7) static inline void xprt_set_connected(struct rpc_xprt *xprt) { diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 2e070679ab4a..b51f58b95c39 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -49,6 +49,8 @@ unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE; unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT; unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT; +#define XS_TCP_LINGER_TO (15U * HZ) + /* * We can register our own files under /proc/sys/sunrpc by * calling register_sysctl_table() again. The files in that @@ -806,6 +808,7 @@ static void xs_close(struct rpc_xprt *xprt) xs_reset_transport(transport); smp_mb__before_clear_bit(); + clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); clear_bit(XPRT_CLOSE_WAIT, &xprt->state); clear_bit(XPRT_CLOSING, &xprt->state); smp_mb__after_clear_bit(); @@ -1133,6 +1136,47 @@ static void xs_tcp_data_ready(struct sock *sk, int bytes) read_unlock(&sk->sk_callback_lock); } +/* + * Do the equivalent of linger/linger2 handling for dealing with + * broken servers that don't close the socket in a timely + * fashion + */ +static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt, + unsigned long timeout) +{ + struct sock_xprt *transport; + + if (xprt_test_and_set_connecting(xprt)) + return; + set_bit(XPRT_CONNECTION_ABORT, &xprt->state); + transport = container_of(xprt, struct sock_xprt, xprt); + queue_delayed_work(rpciod_workqueue, &transport->connect_worker, + timeout); +} + +static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt) +{ + struct sock_xprt *transport; + + transport = container_of(xprt, struct sock_xprt, xprt); + + if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) || + !cancel_delayed_work(&transport->connect_worker)) + return; + clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); + xprt_clear_connecting(xprt); +} + +static void xs_sock_mark_closed(struct rpc_xprt *xprt) +{ + smp_mb__before_clear_bit(); + clear_bit(XPRT_CLOSE_WAIT, &xprt->state); + clear_bit(XPRT_CLOSING, &xprt->state); + smp_mb__after_clear_bit(); + /* Mark transport as closed and wake up all pending tasks */ + xprt_disconnect_done(xprt); +} + /** * xs_tcp_state_change - callback to handle TCP socket state changes * @sk: socket whose state has changed @@ -1178,6 +1222,7 @@ static void xs_tcp_state_change(struct sock *sk) clear_bit(XPRT_CONNECTED, &xprt->state); clear_bit(XPRT_CLOSE_WAIT, &xprt->state); smp_mb__after_clear_bit(); + xs_tcp_schedule_linger_timeout(xprt, XS_TCP_LINGER_TO); break; case TCP_CLOSE_WAIT: /* The server initiated a shutdown of the socket */ @@ -1194,17 +1239,14 @@ static void xs_tcp_state_change(struct sock *sk) break; case TCP_LAST_ACK: set_bit(XPRT_CLOSING, &xprt->state); + xs_tcp_schedule_linger_timeout(xprt, XS_TCP_LINGER_TO); smp_mb__before_clear_bit(); clear_bit(XPRT_CONNECTED, &xprt->state); smp_mb__after_clear_bit(); break; case TCP_CLOSE: - smp_mb__before_clear_bit(); - clear_bit(XPRT_CLOSE_WAIT, &xprt->state); - clear_bit(XPRT_CLOSING, &xprt->state); - smp_mb__after_clear_bit(); - /* Mark transport as closed and wake up all pending tasks */ - xprt_disconnect_done(xprt); + xs_tcp_cancel_linger_timeout(xprt); + xs_sock_mark_closed(xprt); } out: read_unlock(&sk->sk_callback_lock); @@ -1562,8 +1604,8 @@ static void xs_udp_connect_worker4(struct work_struct *work) xs_udp_finish_connecting(xprt, sock); status = 0; out: - xprt_wake_pending_tasks(xprt, status); xprt_clear_connecting(xprt); + xprt_wake_pending_tasks(xprt, status); } /** @@ -1604,8 +1646,8 @@ static void xs_udp_connect_worker6(struct work_struct *work) xs_udp_finish_connecting(xprt, sock); status = 0; out: - xprt_wake_pending_tasks(xprt, status); xprt_clear_connecting(xprt); + xprt_wake_pending_tasks(xprt, status); } /* @@ -1626,7 +1668,9 @@ static void xs_abort_connection(struct rpc_xprt *xprt, struct sock_xprt *transpo memset(&any, 0, sizeof(any)); any.sa_family = AF_UNSPEC; result = kernel_connect(transport->sock, &any, sizeof(any), 0); - if (result) + if (!result) + xs_sock_mark_closed(xprt); + else dprintk("RPC: AF_UNSPEC connect return code %d\n", result); } @@ -1702,6 +1746,7 @@ static void xs_tcp_connect_worker4(struct work_struct *work) goto out; if (!sock) { + clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); /* start from scratch */ if ((err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) { dprintk("RPC: can't create TCP transport socket (%d).\n", -err); @@ -1713,10 +1758,18 @@ static void xs_tcp_connect_worker4(struct work_struct *work) sock_release(sock); goto out; } - } else + } else { + int abort_and_exit; + + abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT, + &xprt->state); /* "close" the socket, preserving the local port */ xs_tcp_reuse_connection(xprt, transport); + if (abort_and_exit) + goto out_eagain; + } + dprintk("RPC: worker connecting xprt %p to address: %s\n", xprt, xprt->address_strings[RPC_DISPLAY_ALL]); @@ -1732,17 +1785,18 @@ static void xs_tcp_connect_worker4(struct work_struct *work) case 0: case -EINPROGRESS: case -EALREADY: - goto out_clear; + 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: - xprt_wake_pending_tasks(xprt, status); -out_clear: xprt_clear_connecting(xprt); + xprt_wake_pending_tasks(xprt, status); } /** @@ -1763,6 +1817,7 @@ static void xs_tcp_connect_worker6(struct work_struct *work) goto out; if (!sock) { + clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); /* start from scratch */ if ((err = sock_create_kern(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) { dprintk("RPC: can't create TCP transport socket (%d).\n", -err); @@ -1774,10 +1829,18 @@ static void xs_tcp_connect_worker6(struct work_struct *work) sock_release(sock); goto out; } - } else + } else { + int abort_and_exit; + + abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT, + &xprt->state); /* "close" the socket, preserving the local port */ xs_tcp_reuse_connection(xprt, transport); + if (abort_and_exit) + goto out_eagain; + } + dprintk("RPC: worker connecting xprt %p to address: %s\n", xprt, xprt->address_strings[RPC_DISPLAY_ALL]); @@ -1792,17 +1855,18 @@ static void xs_tcp_connect_worker6(struct work_struct *work) case 0: case -EINPROGRESS: case -EALREADY: - goto out_clear; + 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: - xprt_wake_pending_tasks(xprt, status); -out_clear: xprt_clear_connecting(xprt); + xprt_wake_pending_tasks(xprt, status); } /**