Commit f5fe8d51 authored by Alexander Aring's avatar Alexander Aring Committed by David Teigland
Browse files

fs: dlm: fix race in mhandle deletion 



This patch fixes a race between mhandle deletion in case of receiving an
acknowledge and flush of all pending mhandle in cases of an timeout or
resetting node states.

Fixes: 489d8e55 ("fs: dlm: add reliable connection if reconnect")
Reported-by: default avatarGuillaume Nault <gnault@redhat.com>
Signed-off-by: default avatarAlexander Aring <aahringo@redhat.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent d10a0b88

fs/dlm/midcomms.c

+21 −14
Original line number Diff line number Diff line
@@ -287,6 +287,14 @@ static void dlm_mhandle_release(struct rcu_head *rcu) 
	kfree(mh);

}



static void dlm_mhandle_delete(struct midcomms_node *node,

			       struct dlm_mhandle *mh)

{

	list_del_rcu(&mh->list);

	atomic_dec(&node->send_queue_cnt);

	call_rcu(&mh->rcu, dlm_mhandle_release);

}



static void dlm_send_queue_flush(struct midcomms_node *node)

{

	struct dlm_mhandle *mh;
@@ -294,15 +302,11 @@ static void dlm_send_queue_flush(struct midcomms_node *node) 
	pr_debug("flush midcomms send queue of node %d\n", node->nodeid);



	rcu_read_lock();

	list_for_each_entry_rcu(mh, &node->send_queue, list) {

	spin_lock(&node->send_queue_lock);

		list_del_rcu(&mh->list);

		spin_unlock(&node->send_queue_lock);



		atomic_dec(&node->send_queue_cnt);



		call_rcu(&mh->rcu, dlm_mhandle_release);

	list_for_each_entry_rcu(mh, &node->send_queue, list) {

		dlm_mhandle_delete(node, mh);

	}

	spin_unlock(&node->send_queue_lock);

	rcu_read_unlock();

}
@@ -424,21 +428,24 @@ static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq) 
	rcu_read_lock();

	list_for_each_entry_rcu(mh, &node->send_queue, list) {

		if (before(mh->seq, seq)) {

			spin_lock(&node->send_queue_lock);

			list_del_rcu(&mh->list);

			spin_unlock(&node->send_queue_lock);



			atomic_dec(&node->send_queue_cnt);



			if (mh->ack_rcv)

				mh->ack_rcv(node);

		} else {

			/* send queue should be ordered */

			break;

		}

	}



			call_rcu(&mh->rcu, dlm_mhandle_release);

	spin_lock(&node->send_queue_lock);

	list_for_each_entry_rcu(mh, &node->send_queue, list) {

		if (before(mh->seq, seq)) {

			dlm_mhandle_delete(node, mh);

		} else {

			/* send queue should be ordered */

			break;

		}

	}

	spin_unlock(&node->send_queue_lock);

	rcu_read_unlock();

}