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Commit b81171cb authored by Bob Peterson's avatar Bob Peterson Committed by David Teigland
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DLM: Save and restore socket callbacks properly 



This patch fixes the problems with patch b3a5bbfd.

1. It removes a return statement from lowcomms_error_report
   because it needs to call the original error report in all paths
   through the function.
2. All socket callbacks are saved and restored, not just the
   sk_error_report, and that's done so with proper locking like
   sunrpc does.

Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent 1a31833d

fs/dlm/lowcomms.c

+59 −11
Original line number Diff line number Diff line
@@ -124,7 +124,10 @@ struct connection { 
	struct connection *othercon;

	struct work_struct rwork; /* Receive workqueue */

	struct work_struct swork; /* Send workqueue */

	void (*orig_error_report)(struct sock *sk);

	void (*orig_error_report)(struct sock *);

	void (*orig_data_ready)(struct sock *);

	void (*orig_state_change)(struct sock *);

	void (*orig_write_space)(struct sock *);

};

#define sock2con(x) ((struct connection *)(x)->sk_user_data)
@@ -467,10 +470,17 @@ int dlm_lowcomms_connect_node(int nodeid) 


static void lowcomms_error_report(struct sock *sk)

{

	struct connection *con = sock2con(sk);

	struct connection *con;

	struct sockaddr_storage saddr;

	int buflen;

	void (*orig_report)(struct sock *) = NULL;



	read_lock_bh(&sk->sk_callback_lock);

	con = sock2con(sk);

	if (con == NULL)

		goto out;



	orig_report = con->orig_error_report;

	if (con->sock == NULL ||

	    kernel_getpeername(con->sock, (struct sockaddr *)&saddr, &buflen)) {

		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
@@ -478,7 +488,6 @@ static void lowcomms_error_report(struct sock *sk) 
				   "sk_err=%d/%d\n", dlm_our_nodeid(),

				   con->nodeid, dlm_config.ci_tcp_port,

				   sk->sk_err, sk->sk_err_soft);

		return;

	} else if (saddr.ss_family == AF_INET) {

		struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
@@ -501,22 +510,54 @@ static void lowcomms_error_report(struct sock *sk) 
				   dlm_config.ci_tcp_port, sk->sk_err,

				   sk->sk_err_soft);

	}

	con->orig_error_report(sk);

out:

	read_unlock_bh(&sk->sk_callback_lock);

	if (orig_report)

		orig_report(sk);

}



/* Note: sk_callback_lock must be locked before calling this function. */

static void save_callbacks(struct connection *con, struct sock *sk)

{

	lock_sock(sk);

	con->orig_data_ready = sk->sk_data_ready;

	con->orig_state_change = sk->sk_state_change;

	con->orig_write_space = sk->sk_write_space;

	con->orig_error_report = sk->sk_error_report;

	release_sock(sk);

}



static void restore_callbacks(struct connection *con, struct sock *sk)

{

	write_lock_bh(&sk->sk_callback_lock);

	lock_sock(sk);

	sk->sk_user_data = NULL;

	sk->sk_data_ready = con->orig_data_ready;

	sk->sk_state_change = con->orig_state_change;

	sk->sk_write_space = con->orig_write_space;

	sk->sk_error_report = con->orig_error_report;

	release_sock(sk);

	write_unlock_bh(&sk->sk_callback_lock);

}



/* Make a socket active */

static void add_sock(struct socket *sock, struct connection *con)

{

	struct sock *sk = sock->sk;



	write_lock_bh(&sk->sk_callback_lock);

	con->sock = sock;



	sk->sk_user_data = con;

	if (!test_bit(CF_IS_OTHERCON, &con->flags))

		save_callbacks(con, sk);

	/* Install a data_ready callback */

	con->sock->sk->sk_data_ready = lowcomms_data_ready;

	con->sock->sk->sk_write_space = lowcomms_write_space;

	con->sock->sk->sk_state_change = lowcomms_state_change;

	con->sock->sk->sk_user_data = con;

	con->sock->sk->sk_allocation = GFP_NOFS;

	con->orig_error_report = con->sock->sk->sk_error_report;

	con->sock->sk->sk_error_report = lowcomms_error_report;

	sk->sk_data_ready = lowcomms_data_ready;

	sk->sk_write_space = lowcomms_write_space;

	sk->sk_state_change = lowcomms_state_change;

	sk->sk_allocation = GFP_NOFS;

	sk->sk_error_report = lowcomms_error_report;

	write_unlock_bh(&sk->sk_callback_lock);

}



/* Add the port number to an IPv6 or 4 sockaddr and return the address
@@ -551,6 +592,8 @@ static void close_connection(struct connection *con, bool and_other, 


	mutex_lock(&con->sock_mutex);

	if (con->sock) {

		if (!test_bit(CF_IS_OTHERCON, &con->flags))

			restore_callbacks(con, con->sock->sk);

		sock_release(con->sock);

		con->sock = NULL;

	}
@@ -1192,6 +1235,8 @@ static struct socket *tcp_create_listen_sock(struct connection *con, 
	if (result < 0) {

		log_print("Failed to set SO_REUSEADDR on socket: %d", result);

	}

	sock->sk->sk_user_data = con;



	con->rx_action = tcp_accept_from_sock;

	con->connect_action = tcp_connect_to_sock;
@@ -1273,6 +1318,7 @@ static int sctp_listen_for_all(void) 
	if (result < 0)

		log_print("Could not set SCTP NODELAY error %d\n", result);



	write_lock_bh(&sock->sk->sk_callback_lock);

	/* Init con struct */

	sock->sk->sk_user_data = con;

	con->sock = sock;
@@ -1280,6 +1326,8 @@ static int sctp_listen_for_all(void) 
	con->rx_action = sctp_accept_from_sock;

	con->connect_action = sctp_connect_to_sock;



	write_unlock_bh(&sock->sk->sk_callback_lock);



	/* Bind to all addresses. */

	if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))

		goto create_delsock;