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: 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>

1 files changed, 16 insertions, 3 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index fa15debcc02b..ddddef0021a0 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -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;