-#ifdef __DQUOT_PARANOIA
- if (atomic_read(&dquot->dq_count))
- BUG();
-#endif
- /* Quota now has no users and it has been written on last dqput() */
+ /* Wait for dquot users */
+ if (atomic_read(&dquot->dq_count)) {
+ DEFINE_WAIT(wait);
+
+ atomic_inc(&dquot->dq_count);
+ prepare_to_wait(&dquot->dq_wait_unused, &wait,
+ TASK_UNINTERRUPTIBLE);
+ spin_unlock(&dq_list_lock);
+ /* Once dqput() wakes us up, we know it's time to free
+ * the dquot.
+ * IMPORTANT: we rely on the fact that there is always
+ * at most one process waiting for dquot to free.
+ * Otherwise dq_count would be > 1 and we would never
+ * wake up.
+ */
+ if (atomic_read(&dquot->dq_count) > 1)
+ schedule();
+ finish_wait(&dquot->dq_wait_unused, &wait);
+ dqput(dquot);
+ /* At this moment dquot() need not exist (it could be
+ * reclaimed by prune_dqcache(). Hence we must
+ * restart. */
+ goto restart;
+ }
+ /*
+ * Quota now has no users and it has been written on last
+ * dqput()
+ */