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>

1 files changed, 11 insertions, 23 deletions

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 10d149c1fde1..6b2013403f46 100644
--- 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;
         }