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Commit 0986fe9b authored by Joseph Qi's avatar Joseph Qi Committed by Linus Torvalds
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ocfs2: fix race between mount and delete node/cluster 



There is a race case between mount and delete node/cluster, which will
lead o2hb_thread to malfunctioning dead loop.

    o2hb_thread
    {
        o2nm_depend_this_node();
        <<<<<< race window, node may have already been deleted, and then
               enter the loop, o2hb thread will be malfunctioning
               because of no configured nodes found.
        while (!kthread_should_stop() &&
               !reg->hr_unclean_stop && !reg->hr_aborted_start) {
    }

So check the return value of o2nm_depend_this_node() is needed.  If node
has been deleted, do not enter the loop and let mount fail.

Signed-off-by: default avatarJoseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 93d911fc

fs/ocfs2/cluster/heartbeat.c

+16 −3
Original line number Diff line number Diff line
@@ -219,7 +219,8 @@ struct o2hb_region { 
	unsigned		hr_unclean_stop:1,

				hr_aborted_start:1,

				hr_item_pinned:1,

				hr_item_dropped:1;

				hr_item_dropped:1,

				hr_node_deleted:1;



	/* protected by the hr_callback_sem */

	struct task_struct 	*hr_task;
@@ -1078,7 +1079,13 @@ static int o2hb_thread(void *data) 
	set_user_nice(current, MIN_NICE);



	/* Pin node */

	o2nm_depend_this_node();

	ret = o2nm_depend_this_node();

	if (ret) {

		mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);

		reg->hr_node_deleted = 1;

		wake_up(&o2hb_steady_queue);

		return 0;

	}



	while (!kthread_should_stop() &&

	       !reg->hr_unclean_stop && !reg->hr_aborted_start) {
@@ -1787,7 +1794,8 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, 
	spin_unlock(&o2hb_live_lock);



	ret = wait_event_interruptible(o2hb_steady_queue,

				atomic_read(&reg->hr_steady_iterations) == 0);

				atomic_read(&reg->hr_steady_iterations) == 0 ||

				reg->hr_node_deleted);

	if (ret) {

		atomic_set(&reg->hr_steady_iterations, 0);

		reg->hr_aborted_start = 1;
@@ -1798,6 +1806,11 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, 
		goto out3;

	}



	if (reg->hr_node_deleted) {

		ret = -EINVAL;

		goto out3;

	}



	/* Ok, we were woken.  Make sure it wasn't by drop_item() */

	spin_lock(&o2hb_live_lock);

	hb_task = reg->hr_task;