diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 0b78bf28ff5daf06b9b4ca92caa5d56f6b375a60..905de02e4386d8b03dd66b62029faac2218f2721 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2007 Oracle. All rights reserved.
+ * Copyright (C) 2014 Fujitsu. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
@@ -21,6 +22,7 @@
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/freezer.h>
+#include <linux/workqueue.h>
#include "async-thread.h"
#define WORK_QUEUED_BIT 0
@@ -727,3 +729,138 @@ void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
wake_up_process(worker->task);
spin_unlock_irqrestore(&worker->lock, flags);
}
+
+struct btrfs_workqueue_struct {
+ struct workqueue_struct *normal_wq;
+ /* List head pointing to ordered work list */
+ struct list_head ordered_list;
+
+ /* Spinlock for ordered_list */
+ spinlock_t list_lock;
+};
+
+struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
+ int flags,
+ int max_active)
+{
+ struct btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
+
+ if (unlikely(!ret))
+ return NULL;
+
+ ret->normal_wq = alloc_workqueue("%s-%s", flags, max_active,
+ "btrfs", name);
+ if (unlikely(!ret->normal_wq)) {
+ kfree(ret);
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&ret->ordered_list);
+ spin_lock_init(&ret->list_lock);
+ return ret;
+}
+
+static void run_ordered_work(struct btrfs_workqueue_struct *wq)
+{
+ struct list_head *list = &wq->ordered_list;
+ struct btrfs_work_struct *work;
+ spinlock_t *lock = &wq->list_lock;
+ unsigned long flags;
+
+ while (1) {
+ spin_lock_irqsave(lock, flags);
+ if (list_empty(list))
+ break;
+ work = list_entry(list->next, struct btrfs_work_struct,
+ ordered_list);
+ if (!test_bit(WORK_DONE_BIT, &work->flags))
+ break;
+
+ /*
+ * we are going to call the ordered done function, but
+ * we leave the work item on the list as a barrier so
+ * that later work items that are done don't have their
+ * functions called before this one returns
+ */
+ if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
+ break;
+ spin_unlock_irqrestore(lock, flags);
+ work->ordered_func(work);
+
+ /* now take the lock again and drop our item from the list */
+ spin_lock_irqsave(lock, flags);
+ list_del(&work->ordered_list);
+ spin_unlock_irqrestore(lock, flags);
+
+ /*
+ * we don't want to call the ordered free functions
+ * with the lock held though
+ */
+ work->ordered_free(work);
+ }
+ spin_unlock_irqrestore(lock, flags);
+}
+
+static void normal_work_helper(struct work_struct *arg)
+{
+ struct btrfs_work_struct *work;
+ struct btrfs_workqueue_struct *wq;
+ int need_order = 0;
+
+ work = container_of(arg, struct btrfs_work_struct, normal_work);
+ /*
+ * We should not touch things inside work in the following cases:
+ * 1) after work->func() if it has no ordered_free
+ * Since the struct is freed in work->func().
+ * 2) after setting WORK_DONE_BIT
+ * The work may be freed in other threads almost instantly.
+ * So we save the needed things here.
+ */
+ if (work->ordered_func)
+ need_order = 1;
+ wq = work->wq;
+
+ work->func(work);
+ if (need_order) {
+ set_bit(WORK_DONE_BIT, &work->flags);
+ run_ordered_work(wq);
+ }
+}
+
+void btrfs_init_work(struct btrfs_work_struct *work,
+ void (*func)(struct btrfs_work_struct *),
+ void (*ordered_func)(struct btrfs_work_struct *),
+ void (*ordered_free)(struct btrfs_work_struct *))
+{
+ work->func = func;
+ work->ordered_func = ordered_func;
+ work->ordered_free = ordered_free;
+ INIT_WORK(&work->normal_work, normal_work_helper);
+ INIT_LIST_HEAD(&work->ordered_list);
+ work->flags = 0;
+}
+
+void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
+ struct btrfs_work_struct *work)
+{
+ unsigned long flags;
+
+ work->wq = wq;
+ if (work->ordered_func) {
+ spin_lock_irqsave(&wq->list_lock, flags);
+ list_add_tail(&work->ordered_list, &wq->ordered_list);
+ spin_unlock_irqrestore(&wq->list_lock, flags);
+ }
+ queue_work(wq->normal_wq, &work->normal_work);
+}
+
+void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+{
+ destroy_workqueue(wq->normal_wq);
+ kfree(wq);
+}
+
+void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
+{
+ workqueue_set_max_active(wq->normal_wq, max);
+}
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index 1f26792683edf195b48db80992c05acae6fd71f0..9d8da53f6dd9fe616927a97ceedb906ca4ec9448 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2007 Oracle. All rights reserved.
+ * Copyright (C) 2014 Fujitsu. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
@@ -118,4 +119,30 @@ void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max,
struct btrfs_workers *async_starter);
void btrfs_requeue_work(struct btrfs_work *work);
void btrfs_set_work_high_prio(struct btrfs_work *work);
+
+struct btrfs_workqueue_struct;
+
+struct btrfs_work_struct {
+ void (*func)(struct btrfs_work_struct *arg);
+ void (*ordered_func)(struct btrfs_work_struct *arg);
+ void (*ordered_free)(struct btrfs_work_struct *arg);
+
+ /* Don't touch things below */
+ struct work_struct normal_work;
+ struct list_head ordered_list;
+ struct btrfs_workqueue_struct *wq;
+ unsigned long flags;
+};
+
+struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
+ int flags,
+ int max_active);
+void btrfs_init_work(struct btrfs_work_struct *work,
+ void (*func)(struct btrfs_work_struct *),
+ void (*ordered_func)(struct btrfs_work_struct *),
+ void (*ordered_free)(struct btrfs_work_struct *));
+void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
+ struct btrfs_work_struct *work);
+void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq);
+void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max);
#endif