Btrfs: cleanup code of btrfs_balance_delayed_items()

- move the condition check for wait into a function
- use wait_event_interruptible instead of prepare-schedule-finish process

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 10d149c..6b20134 100644 (file)
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1349,52 +1349,40 @@ void btrfs_assert_delayed_root_empty(struct btrfs_root *root)
        WARN_ON(btrfs_first_delayed_node(delayed_root));
 }
 
-static int refs_newer(struct btrfs_delayed_root *delayed_root,
-                     int seq, int count)
+static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
 {
        int val = atomic_read(&delayed_root->items_seq);
 
-       if (val < seq || val >= seq + count)
+       if (val < seq || val >= seq + BTRFS_DELAYED_BATCH)
                return 1;
+
+       if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
+               return 1;
+
        return 0;
 }
 
 void btrfs_balance_delayed_items(struct btrfs_root *root)
 {
        struct btrfs_delayed_root *delayed_root;
-       int seq;
 
        delayed_root = btrfs_get_delayed_root(root);
 
        if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
                return;
 
-       seq = atomic_read(&delayed_root->items_seq);
-
        if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
+               int seq;
                int ret;
-               DEFINE_WAIT(__wait);
+
+               seq = atomic_read(&delayed_root->items_seq);
 
                ret = btrfs_wq_run_delayed_node(delayed_root, root, 0);
                if (ret)
                        return;
 
-               while (1) {
-                       prepare_to_wait(&delayed_root->wait, &__wait,
-                                       TASK_INTERRUPTIBLE);
-
-                       if (refs_newer(delayed_root, seq,
-                                      BTRFS_DELAYED_BATCH) ||
-                           atomic_read(&delayed_root->items) <
-                           BTRFS_DELAYED_BACKGROUND) {
-                               break;
-                       }
-                       if (!signal_pending(current))
-                               schedule();
-                       else
-                               break;
-               }
-               finish_wait(&delayed_root->wait, &__wait);
+               wait_event_interruptible(delayed_root->wait,
+                                        could_end_wait(delayed_root, seq));
                return;
        }