Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

[safe/jmp/linux-2.6] / mm / backing-dev.c

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 67a33a5..660a87a 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -11,6 +11,8 @@
 #include <linux/writeback.h>
 #include <linux/device.h>
 
+static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
 void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 {
 }
@@ -25,6 +27,11 @@ struct backing_dev_info default_backing_dev_info = {
 };
 EXPORT_SYMBOL_GPL(default_backing_dev_info);
 
+struct backing_dev_info noop_backing_dev_info = {
+       .name           = "noop",
+};
+EXPORT_SYMBOL_GPL(noop_backing_dev_info);
+
 static struct class *bdi_class;
 
 /*
@@ -41,7 +48,6 @@ static struct timer_list sync_supers_timer;
 
 static int bdi_sync_supers(void *);
 static void sync_supers_timer_fn(unsigned long);
-static void arm_supers_timer(void);
 
 static void bdi_add_default_flusher_task(struct backing_dev_info *bdi);
 
@@ -227,6 +233,9 @@ static struct device_attribute bdi_dev_attrs[] = {
 static __init int bdi_class_init(void)
 {
        bdi_class = class_create(THIS_MODULE, "bdi");
+       if (IS_ERR(bdi_class))
+               return PTR_ERR(bdi_class);
+
        bdi_class->dev_attrs = bdi_dev_attrs;
        bdi_debug_init();
        return 0;
@@ -242,7 +251,7 @@ static int __init default_bdi_init(void)
 
        init_timer(&sync_supers_timer);
        setup_timer(&sync_supers_timer, sync_supers_timer_fn, 0);
-       arm_supers_timer();
+       bdi_arm_supers_timer();
 
        err = bdi_init(&default_backing_dev_info);
        if (!err)
@@ -364,10 +373,13 @@ static int bdi_sync_supers(void *unused)
        return 0;
 }
 
-static void arm_supers_timer(void)
+void bdi_arm_supers_timer(void)
 {
        unsigned long next;
 
+       if (!dirty_writeback_interval)
+               return;
+
        next = msecs_to_jiffies(dirty_writeback_interval * 10) + jiffies;
        mod_timer(&sync_supers_timer, round_jiffies_up(next));
 }
@@ -375,7 +387,7 @@ static void arm_supers_timer(void)
 static void sync_supers_timer_fn(unsigned long unused)
 {
        wake_up_process(sync_supers_tsk);
-       arm_supers_timer();
+       bdi_arm_supers_timer();
 }
 
 static int bdi_forker_task(void *ptr)
@@ -418,7 +430,10 @@ static int bdi_forker_task(void *ptr)
 
                        spin_unlock_bh(&bdi_lock);
                        wait = msecs_to_jiffies(dirty_writeback_interval * 10);
-                       schedule_timeout(wait);
+                       if (wait)
+                               schedule_timeout(wait);
+                       else
+                               schedule();
                        try_to_freeze();
                        continue;
                }
@@ -609,7 +624,7 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
         * it would never exet if it is currently stuck in the refrigerator.
         */
        list_for_each_entry(wb, &bdi->wb_list, list) {
-               wb->task->flags &= ~PF_FROZEN;
+               thaw_process(wb->task);
                kthread_stop(wb->task);
        }
 }
@@ -712,6 +727,33 @@ void bdi_destroy(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL(bdi_destroy);
 
+/*
+ * For use from filesystems to quickly init and register a bdi associated
+ * with dirty writeback
+ */
+int bdi_setup_and_register(struct backing_dev_info *bdi, char *name,
+                          unsigned int cap)
+{
+       char tmp[32];
+       int err;
+
+       bdi->name = name;
+       bdi->capabilities = cap;
+       err = bdi_init(bdi);
+       if (err)
+               return err;
+
+       sprintf(tmp, "%.28s%s", name, "-%d");
+       err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq));
+       if (err) {
+               bdi_destroy(bdi);
+               return err;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL(bdi_setup_and_register);
+
 static wait_queue_head_t congestion_wqh[2] = {
                __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
                __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])