drbd: fix potential list_add corruption

If the md_sync_timer triggers a second time,
while the work queued during the first time is still pending,
this could result in list_add() of an already added item,
and corrupt the work item list.

This likely only triggered because of the erroneous
batch-dequeueing of work items fixed with
  drbd: dequeue single work items in wait_for_work()

Still, skip queueing if md_sync_work is already queued.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg 2012-08-22 14:59:06 +02:00 committed by Philipp Reisner
parent bc317a9ecd
commit b792b655cd

View File

@ -3314,7 +3314,9 @@ static void md_sync_timer_fn(unsigned long data)
{
struct drbd_conf *mdev = (struct drbd_conf *) data;
drbd_queue_work_front(&mdev->tconn->sender_work, &mdev->md_sync_work);
/* must not double-queue! */
if (list_empty(&mdev->md_sync_work.list))
drbd_queue_work_front(&mdev->tconn->sender_work, &mdev->md_sync_work);
}
static int w_md_sync(struct drbd_work *w, int unused)