btrfs: breakout empty head cleanup to a helper

Move this code out to a helper function to further simplivy
__btrfs_run_delayed_refs.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -2605,6 +2605,43 @@ static int cleanup_extent_op(struct btrfs_trans_handle *trans,
 	return ret ? ret : 1;
 }
 
+static int cleanup_ref_head(struct btrfs_trans_handle *trans,
+			    struct btrfs_fs_info *fs_info,
+			    struct btrfs_delayed_ref_head *head)
+{
+	struct btrfs_delayed_ref_root *delayed_refs;
+	int ret;
+
+	delayed_refs = &trans->transaction->delayed_refs;
+
+	ret = cleanup_extent_op(trans, fs_info, head);
+	if (ret < 0) {
+		unselect_delayed_ref_head(delayed_refs, head);
+		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
+		return ret;
+	} else if (ret) {
+		return ret;
+	}
+
+	/*
+	 * Need to drop our head ref lock and re-acquire the delayed ref lock
+	 * and then re-check to make sure nobody got added.
+	 */
+	spin_unlock(&head->lock);
+	spin_lock(&delayed_refs->lock);
+	spin_lock(&head->lock);
+	if (!list_empty(&head->ref_list) || head->extent_op) {
+		spin_unlock(&head->lock);
+		spin_unlock(&delayed_refs->lock);
+		return 1;
+	}
+	head->node.in_tree = 0;
+	delayed_refs->num_heads--;
+	rb_erase(&head->href_node, &delayed_refs->href_root);
+	spin_unlock(&delayed_refs->lock);
+	return 0;
+}
+
 /*
  * Returns 0 on success or if called with an already aborted transaction.
  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
@@ -2686,47 +2723,21 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 		}
 
 		if (!ref) {
-
-
-			/* All delayed refs have been processed, Go ahead
-			 * and send the head node to run_one_delayed_ref,
-			 * so that any accounting fixes can happen
-			 */
-			ref = &locked_ref->node;
-
-			ret = cleanup_extent_op(trans, fs_info, locked_ref);
-			if (ret < 0) {
-				unselect_delayed_ref_head(delayed_refs,
-							  locked_ref);
-				btrfs_debug(fs_info,
-					    "run_delayed_extent_op returned %d",
-					    ret);
-				return ret;
-			} else if (ret > 0) {
+			ret = cleanup_ref_head(trans, fs_info, locked_ref);
+			if (ret > 0 ) {
 				/* We dropped our lock, we need to loop. */
 				ret = 0;
 				continue;
+			} else if (ret) {
+				return ret;
 			}
 
 			/*
-			 * Need to drop our head ref lock and re-acquire the
-			 * delayed ref lock and then re-check to make sure
-			 * nobody got added.
+			 * All delayed refs have been processed, Go ahead and
+			 * send the head node to run_one_delayed_ref, so that
+			 * any accounting fixes can happen
 			 */
-			spin_unlock(&locked_ref->lock);
-			spin_lock(&delayed_refs->lock);
-			spin_lock(&locked_ref->lock);
-			if (!list_empty(&locked_ref->ref_list) ||
-			    locked_ref->extent_op) {
-				spin_unlock(&locked_ref->lock);
-				spin_unlock(&delayed_refs->lock);
-				continue;
-			}
-			ref->in_tree = 0;
-			delayed_refs->num_heads--;
-			rb_erase(&locked_ref->href_node,
-				 &delayed_refs->href_root);
-			spin_unlock(&delayed_refs->lock);
+			ref = &locked_ref->node;
 		} else {
 			actual_count++;
 			ref->in_tree = 0;