From 0445f92c5d537c173a54446b80d2052145de5148 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 17 Dec 2018 13:34:59 -0500 Subject: [PATCH 1/3] SUNRPC: Fix disconnection races When the socket is closed, we need to call xprt_disconnect_done() in order to clean up the XPRT_WRITE_SPACE flag, and wake up the sleeping tasks. However, we also want to ensure that we don't wake them up before the socket is closed, since that would cause thundering herd issues with everyone piling up to retransmit before the TCP shutdown dance has completed. Only the task that holds XPRT_LOCKED needs to wake up early in order to allow the close to complete. Reported-by: Dave Wysochanski Reported-by: Scott Mayhew Cc: Chuck Lever Signed-off-by: Trond Myklebust Tested-by: Chuck Lever --- net/sunrpc/clnt.c | 1 + net/sunrpc/xprt.c | 5 ++++- net/sunrpc/xprtsock.c | 6 ++---- 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index c6782aa47525..24cbddc44c88 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1952,6 +1952,7 @@ call_connect_status(struct rpc_task *task) /* retry with existing socket, after a delay */ rpc_delay(task, 3*HZ); /* fall through */ + case -ENOTCONN: case -EAGAIN: /* Check for timeouts before looping back to call_bind */ case -ETIMEDOUT: diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index ce927002862a..3fb001dff670 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -680,7 +680,9 @@ void xprt_force_disconnect(struct rpc_xprt *xprt) /* Try to schedule an autoclose RPC call */ if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) queue_work(xprtiod_workqueue, &xprt->task_cleanup); - xprt_wake_pending_tasks(xprt, -EAGAIN); + else if (xprt->snd_task) + rpc_wake_up_queued_task_set_status(&xprt->pending, + xprt->snd_task, -ENOTCONN); spin_unlock_bh(&xprt->transport_lock); } EXPORT_SYMBOL_GPL(xprt_force_disconnect); @@ -852,6 +854,7 @@ static void xprt_connect_status(struct rpc_task *task) case -ENETUNREACH: case -EHOSTUNREACH: case -EPIPE: + case -ENOTCONN: case -EAGAIN: dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid); break; diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 8a5e823e0b33..4c471b4235ba 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1217,6 +1217,8 @@ static void xs_reset_transport(struct sock_xprt *transport) trace_rpc_socket_close(xprt, sock); sock_release(sock); + + xprt_disconnect_done(xprt); } /** @@ -1237,8 +1239,6 @@ static void xs_close(struct rpc_xprt *xprt) xs_reset_transport(transport); xprt->reestablish_timeout = 0; - - xprt_disconnect_done(xprt); } static void xs_inject_disconnect(struct rpc_xprt *xprt) @@ -1489,8 +1489,6 @@ static void xs_tcp_state_change(struct sock *sk) &transport->sock_state)) xprt_clear_connecting(xprt); clear_bit(XPRT_CLOSING, &xprt->state); - if (sk->sk_err) - xprt_wake_pending_tasks(xprt, -sk->sk_err); /* Trigger the socket release */ xs_tcp_force_close(xprt); } From cf76785d30712d90185455e752337acdb53d2a5d Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 17 Dec 2018 17:38:51 -0500 Subject: [PATCH 2/3] SUNRPC: Fix a race with XPRT_CONNECTING Ensure that we clear XPRT_CONNECTING before releasing the XPRT_LOCK so that we don't have races between the (asynchronous) socket setup code and tasks in xprt_connect(). Signed-off-by: Trond Myklebust Tested-by: Chuck Lever --- net/sunrpc/xprtsock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 4c471b4235ba..f0b3700cec95 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -2090,8 +2090,8 @@ static void xs_udp_setup_socket(struct work_struct *work) trace_rpc_socket_connect(xprt, sock, 0); status = 0; out: - xprt_unlock_connect(xprt, transport); xprt_clear_connecting(xprt); + xprt_unlock_connect(xprt, transport); xprt_wake_pending_tasks(xprt, status); } @@ -2327,8 +2327,8 @@ static void xs_tcp_setup_socket(struct work_struct *work) } status = -EAGAIN; out: - xprt_unlock_connect(xprt, transport); xprt_clear_connecting(xprt); + xprt_unlock_connect(xprt, transport); xprt_wake_pending_tasks(xprt, status); } From abc13275771fac77e2d7b129c289522dacb644b6 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 17 Dec 2018 17:33:33 -0500 Subject: [PATCH 3/3] SUNRPC: Remove xprt_connect_status() Over the years, xprt_connect_status() has been superseded by call_connect_status(), which now handles all the errors that xprt_connect_status() does and more. Since the latter converts all errors that it doesn't recognise to EIO, then it is time for it to be retired. Reported-by: Chuck Lever Signed-off-by: Trond Myklebust Tested-by: Chuck Lever --- net/sunrpc/xprt.c | 32 +------------------------------- 1 file changed, 1 insertion(+), 31 deletions(-) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 3fb001dff670..73547d17d3c6 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -67,7 +67,6 @@ */ static void xprt_init(struct rpc_xprt *xprt, struct net *net); static __be32 xprt_alloc_xid(struct rpc_xprt *xprt); -static void xprt_connect_status(struct rpc_task *task); static void xprt_destroy(struct rpc_xprt *xprt); static DEFINE_SPINLOCK(xprt_list_lock); @@ -822,7 +821,7 @@ void xprt_connect(struct rpc_task *task) if (!xprt_connected(xprt)) { task->tk_timeout = task->tk_rqstp->rq_timeout; task->tk_rqstp->rq_connect_cookie = xprt->connect_cookie; - rpc_sleep_on(&xprt->pending, task, xprt_connect_status); + rpc_sleep_on(&xprt->pending, task, NULL); if (test_bit(XPRT_CLOSING, &xprt->state)) return; @@ -841,35 +840,6 @@ void xprt_connect(struct rpc_task *task) xprt_release_write(xprt, task); } -static void xprt_connect_status(struct rpc_task *task) -{ - switch (task->tk_status) { - case 0: - dprintk("RPC: %5u xprt_connect_status: connection established\n", - task->tk_pid); - break; - case -ECONNREFUSED: - case -ECONNRESET: - case -ECONNABORTED: - case -ENETUNREACH: - case -EHOSTUNREACH: - case -EPIPE: - case -ENOTCONN: - case -EAGAIN: - dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid); - break; - case -ETIMEDOUT: - dprintk("RPC: %5u xprt_connect_status: connect attempt timed " - "out\n", task->tk_pid); - break; - default: - dprintk("RPC: %5u xprt_connect_status: error %d connecting to " - "server %s\n", task->tk_pid, -task->tk_status, - task->tk_rqstp->rq_xprt->servername); - task->tk_status = -EIO; - } -} - enum xprt_xid_rb_cmp { XID_RB_EQUAL, XID_RB_LEFT,