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Commit f1f1c1cc authored by Patrick Caulfield's avatar Patrick Caulfield Committed by Steven Whitehouse
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[DLM] Make sock_sem into a mutex 



Now that there can be multiple dlm_recv threads running we need to prevent two
recvs running for the same connection - it's unlikely but it can happen and it
causes message corruption.

Signed-Off-By: default avatarPatrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent d043e190

fs/dlm/lowcomms-tcp.c

+22 −22
Original line number Diff line number Diff line
@@ -96,7 +96,7 @@ static bool cbuf_empty(struct cbuf *cb) 
struct connection {

	struct socket *sock;	/* NULL if not connected */

	uint32_t nodeid;	/* So we know who we are in the list */

	struct rw_semaphore sock_sem; /* Stop connect races */

	struct mutex sock_mutex;

	unsigned long flags;	/* bit 1,2 = We are on the read/write lists */

#define CF_READ_PENDING 1

#define CF_WRITE_PENDING 2
@@ -171,7 +171,7 @@ static struct connection *nodeid2con(int nodeid, gfp_t allocation) 
			goto finish;



		con->nodeid = nodeid;

		init_rwsem(&con->sock_sem);

		mutex_init(&con->sock_mutex);

		INIT_LIST_HEAD(&con->writequeue);

		spin_lock_init(&con->writequeue_lock);

		INIT_WORK(&con->swork, process_send_sockets);
@@ -247,7 +247,7 @@ static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port, 
/* Close a remote connection and tidy up */

static void close_connection(struct connection *con, bool and_other)

{

	down_write(&con->sock_sem);

	mutex_lock(&con->sock_mutex);



	if (con->sock) {

		sock_release(con->sock);
@@ -262,7 +262,7 @@ static void close_connection(struct connection *con, bool and_other) 
		con->rx_page = NULL;

	}

	con->retries = 0;

	up_write(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

}



/* Data received from remote end */
@@ -276,7 +276,7 @@ static int receive_from_sock(struct connection *con) 
	int r;

	int call_again_soon = 0;



	down_read(&con->sock_sem);

	mutex_lock(&con->sock_mutex);



	if (con->sock == NULL)

		goto out;
@@ -355,17 +355,17 @@ static int receive_from_sock(struct connection *con) 
out:

	if (call_again_soon)

		goto out_resched;

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	return 0;



out_resched:

	if (!test_and_set_bit(CF_READ_PENDING, &con->flags))

		queue_work(recv_workqueue, &con->rwork);

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	return -EAGAIN;



out_close:

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	if (ret != -EAGAIN && !test_bit(CF_IS_OTHERCON, &con->flags)) {

		close_connection(con, false);

		/* Reconnect when there is something to send */
@@ -391,7 +391,7 @@ static int accept_from_sock(struct connection *con) 
	if (result < 0)

		return -ENOMEM;



	down_read_nested(&con->sock_sem, 0);

	mutex_lock_nested(&con->sock_mutex, 0);



	result = -ENOTCONN;

	if (con->sock == NULL)
@@ -417,7 +417,7 @@ static int accept_from_sock(struct connection *con) 
	if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {

		printk("dlm: connect from non cluster node\n");

		sock_release(newsock);

		up_read(&con->sock_sem);

		mutex_unlock(&con->sock_mutex);

		return -1;

	}
@@ -434,7 +434,7 @@ static int accept_from_sock(struct connection *con) 
		result = -ENOMEM;

		goto accept_err;

	}

	down_write_nested(&newcon->sock_sem, 1);

	mutex_lock_nested(&newcon->sock_mutex, 1);

	if (newcon->sock) {

		struct connection *othercon = newcon->othercon;
@@ -442,13 +442,13 @@ static int accept_from_sock(struct connection *con) 
			othercon = kmem_cache_zalloc(con_cache, GFP_KERNEL);

			if (!othercon) {

				printk("dlm: failed to allocate incoming socket\n");

				up_write(&newcon->sock_sem);

				mutex_unlock(&newcon->sock_mutex);

				result = -ENOMEM;

				goto accept_err;

			}

			othercon->nodeid = nodeid;

			othercon->rx_action = receive_from_sock;

			init_rwsem(&othercon->sock_sem);

			mutex_init(&othercon->sock_mutex);

			INIT_WORK(&othercon->swork, process_send_sockets);

			INIT_WORK(&othercon->rwork, process_recv_sockets);

			set_bit(CF_IS_OTHERCON, &othercon->flags);
@@ -466,7 +466,7 @@ static int accept_from_sock(struct connection *con) 
		addcon = newcon;

	}



	up_write(&newcon->sock_sem);

	mutex_unlock(&newcon->sock_mutex);



	/*

	 * Add it to the active queue in case we got data
@@ -475,12 +475,12 @@ static int accept_from_sock(struct connection *con) 
	 */

	if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))

		queue_work(recv_workqueue, &addcon->rwork);

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);



	return 0;



accept_err:

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	sock_release(newsock);



	if (result != -EAGAIN)
@@ -501,7 +501,7 @@ static void connect_to_sock(struct connection *con) 
		return;

	}



	down_write(&con->sock_sem);

	mutex_lock(&con->sock_mutex);

	if (con->retries++ > MAX_CONNECT_RETRIES)

		goto out;
@@ -553,7 +553,7 @@ out_err: 
		result = 0;

	}

out:

	up_write(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	return;

}
@@ -757,7 +757,7 @@ static void send_to_sock(struct connection *con) 
	struct writequeue_entry *e;

	int len, offset;



	down_read(&con->sock_sem);

	mutex_lock(&con->sock_mutex);

	if (con->sock == NULL)

		goto out_connect;
@@ -803,17 +803,17 @@ static void send_to_sock(struct connection *con) 
	}

	spin_unlock(&con->writequeue_lock);

out:

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	return;



send_error:

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	close_connection(con, false);

	lowcomms_connect_sock(con);

	return;



out_connect:

	up_read(&con->sock_sem);

	mutex_unlock(&con->sock_mutex);

	connect_to_sock(con);

	return;

}