ocfs2: move dlm work to a private work queue

The work that is done can block for long periods of time and so is not
appropriate for keventd.

Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

fs/ocfs2/dlm/dlmcommon.h

@@ -131,6 +131,7 @@ struct dlm_ctxt
 	struct o2hb_callback_func dlm_hb_down;
 	struct task_struct *dlm_thread_task;
 	struct task_struct *dlm_reco_thread_task;
+	struct workqueue_struct *dlm_worker;
 	wait_queue_head_t dlm_thread_wq;
 	wait_queue_head_t dlm_reco_thread_wq;
 	wait_queue_head_t ast_wq;

fs/ocfs2/dlm/dlmdomain.c

@@ -303,11 +303,21 @@ int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
 	return ret;
 }
 
+static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
+{
+	if (dlm->dlm_worker) {
+		flush_workqueue(dlm->dlm_worker);
+		destroy_workqueue(dlm->dlm_worker);
+		dlm->dlm_worker = NULL;
+	}
+}
+
 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
 {
 	dlm_unregister_domain_handlers(dlm);
 	dlm_complete_thread(dlm);
 	dlm_complete_recovery_thread(dlm);
+	dlm_destroy_dlm_worker(dlm);
 
 	/* We've left the domain. Now we can take ourselves out of the
 	 * list and allow the kref stuff to help us free the
@@ -1151,6 +1161,13 @@ static int dlm_join_domain(struct dlm_ctxt *dlm)
 		goto bail;
 	}
 
+	dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
+	if (!dlm->dlm_worker) {
+		status = -ENOMEM;
+		mlog_errno(status);
+		goto bail;
+	}
+
 	do {
 		unsigned int backoff;
 		status = dlm_try_to_join_domain(dlm);
@@ -1191,6 +1208,7 @@ bail:
 		dlm_unregister_domain_handlers(dlm);
 		dlm_complete_thread(dlm);
 		dlm_complete_recovery_thread(dlm);
+		dlm_destroy_dlm_worker(dlm);
 	}
 
 	return status;
@@ -1256,6 +1274,7 @@ static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
 
 	dlm->dlm_thread_task = NULL;
 	dlm->dlm_reco_thread_task = NULL;
+	dlm->dlm_worker = NULL;
 	init_waitqueue_head(&dlm->dlm_thread_wq);
 	init_waitqueue_head(&dlm->dlm_reco_thread_wq);
 	init_waitqueue_head(&dlm->reco.event);

fs/ocfs2/dlm/dlmmaster.c

@@ -1962,7 +1962,7 @@ int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
 	list_add_tail(&item->list, &dlm->work_list);
 	spin_unlock(&dlm->work_lock);
 
-	schedule_work(&dlm->dispatched_work);
+	queue_work(dlm->dlm_worker, &dlm->dispatched_work);
 	return 0;
 }
 

fs/ocfs2/dlm/dlmrecovery.c

@@ -157,11 +157,20 @@ void dlm_dispatch_work(void *data)
 	struct list_head *iter, *iter2;
 	struct dlm_work_item *item;
 	dlm_workfunc_t *workfunc;
+	int tot=0;
+
+	if (!dlm_joined(dlm))
+		return;
 
 	spin_lock(&dlm->work_lock);
 	list_splice_init(&dlm->work_list, &tmp_list);
 	spin_unlock(&dlm->work_lock);
 
+	list_for_each_safe(iter, iter2, &tmp_list) {
+		tot++;
+	}
+	mlog(0, "%s: work thread has %d work items\n", dlm->name, tot);
+
 	list_for_each_safe(iter, iter2, &tmp_list) {
 		item = list_entry(iter, struct dlm_work_item, list);
 		workfunc = item->func;
@@ -851,7 +860,7 @@ int dlm_request_all_locks_handler(struct o2net_msg *msg, u32 len, void *data)
 	spin_lock(&dlm->work_lock);
 	list_add_tail(&item->list, &dlm->work_list);
 	spin_unlock(&dlm->work_lock);
-	schedule_work(&dlm->dispatched_work);
+	queue_work(dlm->dlm_worker, &dlm->dispatched_work);
 
 	dlm_put(dlm);
 	return 0;
@@ -1401,7 +1410,7 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data)
 	spin_lock(&dlm->work_lock);
 	list_add_tail(&item->list, &dlm->work_list);
 	spin_unlock(&dlm->work_lock);
-	schedule_work(&dlm->dispatched_work);
+	queue_work(dlm->dlm_worker, &dlm->dispatched_work);
 
 leave:
 	dlm_put(dlm);