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ocfs2: fix race between mount and delete node/cluster

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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: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joseph Qi 2015-11-05 18:44:07 -08:00 committed by Linus Torvalds
parent 93d911fcce
commit 0986fe9b50
1 changed files with 16 additions and 3 deletions
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19
fs/ocfs2/cluster/heartbeat.c
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@ -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;