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Commit 513ef596 authored by David Teigland's avatar David Teigland
Browse files

dlm: prevent connections during shutdown 



During lowcomms shutdown, a new connection could possibly
be created, and attempt to use a workqueue that's been
destroyed.  Similarly, during startup, a new connection
could attempt to use a workqueue that's not been set up
yet.  Add a global variable to indicate when new connections
are allowed.

Based on patch by: Christine Caulfield <ccaulfie@redhat.com>

Reported-by: default avatardann frazier <dann.frazier@canonical.com>
Reviewed-by: default avatardann frazier <dann.frazier@canonical.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent af3a3ab2

fs/dlm/lowcomms.c

+20 −8
Original line number Diff line number Diff line
@@ -142,6 +142,7 @@ struct writequeue_entry { 


static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];

static int dlm_local_count;

static int dlm_allow_conn;



/* Work queues */

static struct workqueue_struct *recv_workqueue;
@@ -710,6 +711,13 @@ static int tcp_accept_from_sock(struct connection *con) 
	struct connection *newcon;

	struct connection *addcon;



	mutex_lock(&connections_lock);

	if (!dlm_allow_conn) {

		mutex_unlock(&connections_lock);

		return -1;

	}

	mutex_unlock(&connections_lock);



	memset(&peeraddr, 0, sizeof(peeraddr));

	result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,

				  IPPROTO_TCP, &newsock);
@@ -1503,6 +1511,7 @@ void dlm_lowcomms_stop(void) 
	   socket activity.

	*/

	mutex_lock(&connections_lock);

	dlm_allow_conn = 0;

	foreach_conn(stop_conn);

	mutex_unlock(&connections_lock);
@@ -1530,7 +1539,7 @@ int dlm_lowcomms_start(void) 
	if (!dlm_local_count) {

		error = -ENOTCONN;

		log_print("no local IP address has been set");

		goto out;

		goto fail;

	}



	error = -ENOMEM;
@@ -1538,7 +1547,13 @@ int dlm_lowcomms_start(void) 
				      __alignof__(struct connection), 0,

				      NULL);

	if (!con_cache)

		goto out;

		goto fail;



	error = work_start();

	if (error)

		goto fail_destroy;



	dlm_allow_conn = 1;



	/* Start listening */

	if (dlm_config.ci_protocol == 0)
@@ -1548,20 +1563,17 @@ int dlm_lowcomms_start(void) 
	if (error)

		goto fail_unlisten;



	error = work_start();

	if (error)

		goto fail_unlisten;



	return 0;



fail_unlisten:

	dlm_allow_conn = 0;

	con = nodeid2con(0,0);

	if (con) {

		close_connection(con, false);

		kmem_cache_free(con_cache, con);

	}

fail_destroy:

	kmem_cache_destroy(con_cache);



out:

fail:

	return error;

}