static noinline int __push_leaf_left(struct btrfs_path *path, int data_size,
				     int empty, struct extent_buffer *left,
				     int free_space, u32 right_nritems,
				     u32 max_slot)
{
	struct btrfs_fs_info *fs_info = left->fs_info;
	struct btrfs_disk_key disk_key;
	struct extent_buffer *right = path->nodes[0];
	int i;
	int push_space = 0;
	int push_items = 0;
	struct btrfs_item *item;
	u32 old_left_nritems;
	u32 nr;
	int ret = 0;
	u32 this_item_size;
	u32 old_left_item_size;
	struct btrfs_map_token token;

	if (empty)
		nr = min(right_nritems, max_slot);
	else
		nr = min(right_nritems - 1, max_slot);

	for (i = 0; i < nr; i++) {
		item = btrfs_item_nr(i);

		if (!empty && push_items > 0) {
			if (path->slots[0] < i)
				break;
			if (path->slots[0] == i) {
				int space = btrfs_leaf_free_space(right);

				if (space + push_space * 2 > free_space)
					break;
			}
		}

		if (path->slots[0] == i)
			push_space += data_size;

		this_item_size = btrfs_item_size(right, item);
		if (this_item_size + sizeof(*item) + push_space > free_space)
			break;

		push_items++;
		push_space += this_item_size + sizeof(*item);
	}

	if (push_items == 0) {
		ret = 1;
		goto out;
	}
	WARN_ON(!empty && push_items == btrfs_header_nritems(right));

	/* push data from right to left */
	copy_extent_buffer(left, right,
			   btrfs_item_nr_offset(btrfs_header_nritems(left)),
			   btrfs_item_nr_offset(0),
			   push_items * sizeof(struct btrfs_item));

	push_space = BTRFS_LEAF_DATA_SIZE(fs_info) -
		     btrfs_item_offset_nr(right, push_items - 1);

	copy_extent_buffer(left, right, BTRFS_LEAF_DATA_OFFSET +
		     leaf_data_end(left) - push_space,
		     BTRFS_LEAF_DATA_OFFSET +
		     btrfs_item_offset_nr(right, push_items - 1),
		     push_space);
	old_left_nritems = btrfs_header_nritems(left);
	BUG_ON(old_left_nritems <= 0);

	btrfs_init_map_token(&token, left);
	old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
	for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
		u32 ioff;

		item = btrfs_item_nr(i);

		ioff = btrfs_token_item_offset(&token, item);
		btrfs_set_token_item_offset(&token, item,
		      ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size));
	}
	btrfs_set_header_nritems(left, old_left_nritems + push_items);

	/* fixup right node */
	if (push_items > right_nritems)
		WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
		       right_nritems);

	if (push_items < right_nritems) {
		push_space = btrfs_item_offset_nr(right, push_items - 1) -
						  leaf_data_end(right);
		memmove_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET +
				      BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
				      BTRFS_LEAF_DATA_OFFSET +
				      leaf_data_end(right), push_space);

		memmove_extent_buffer(right, btrfs_item_nr_offset(0),
			      btrfs_item_nr_offset(push_items),
			     (btrfs_header_nritems(right) - push_items) *
			     sizeof(struct btrfs_item));
	}

	btrfs_init_map_token(&token, right);
	right_nritems -= push_items;
	btrfs_set_header_nritems(right, right_nritems);
	push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
	for (i = 0; i < right_nritems; i++) {
		item = btrfs_item_nr(i);

		push_space = push_space - btrfs_token_item_size(&token, item);
		btrfs_set_token_item_offset(&token, item, push_space);
	}

	btrfs_mark_buffer_dirty(left);
	if (right_nritems)
		btrfs_mark_buffer_dirty(right);
	else
		btrfs_clean_tree_block(right);

	btrfs_item_key(right, &disk_key, 0);
	fixup_low_keys(path, &disk_key, 1);

	/* then fixup the leaf pointer in the path */
	if (path->slots[0] < push_items) {
		path->slots[0] += old_left_nritems;
		btrfs_tree_unlock(path->nodes[0]);
		free_extent_buffer(path->nodes[0]);
		path->nodes[0] = left;
		path->slots[1] -= 1;
	} else {
		btrfs_tree_unlock(left);
		free_extent_buffer(left);
		path->slots[0] -= push_items;
	}
	BUG_ON(path->slots[0] < 0);
	return ret;
out:
	btrfs_tree_unlock(left);
	free_extent_buffer(left);
	return ret;
}
static noinline int __push_leaf_left(struct btrfs_path *path, int data_size,
				     int empty, struct extent_buffer *left,
				     int free_space, u32 right_nritems,
				     u32 max_slot)
{
	struct btrfs_fs_info *fs_info = left->fs_info;
	struct btrfs_disk_key disk_key;
	struct extent_buffer *right = path->nodes[0];
	int i;
	int push_space = 0;
	int push_items = 0;
	struct btrfs_item *item;
	u32 old_left_nritems;
	u32 nr;
	int ret = 0;
	u32 this_item_size;
	u32 old_left_item_size;
	struct btrfs_map_token token;

	if (empty)
		nr = min(right_nritems, max_slot);
	else
		nr = min(right_nritems - 1, max_slot);

	for (i = 0; i < nr; i++) {
		item = btrfs_item_nr(i);

		if (!empty && push_items > 0) {
			if (path->slots[0] < i)
				break;
			if (path->slots[0] == i) {
				int space = btrfs_leaf_free_space(right);

				if (space + push_space * 2 > free_space)
					break;
			}
		}

		if (path->slots[0] == i)
			push_space += data_size;

		this_item_size = btrfs_item_size(right, item);
		if (this_item_size + sizeof(*item) + push_space > free_space)
			break;

		push_items++;
		push_space += this_item_size + sizeof(*item);
	}

	if (push_items == 0) {
		ret = 1;
		goto out;
	}
	WARN_ON(!empty && push_items == btrfs_header_nritems(right));

	 
	copy_extent_buffer(left, right,
			   btrfs_item_nr_offset(btrfs_header_nritems(left)),
			   btrfs_item_nr_offset(0),
			   push_items * sizeof(struct btrfs_item));

	push_space = BTRFS_LEAF_DATA_SIZE(fs_info) -
		     btrfs_item_offset_nr(right, push_items - 1);

	copy_extent_buffer(left, right, BTRFS_LEAF_DATA_OFFSET +
		     leaf_data_end(left) - push_space,
		     BTRFS_LEAF_DATA_OFFSET +
		     btrfs_item_offset_nr(right, push_items - 1),
		     push_space);
	old_left_nritems = btrfs_header_nritems(left);
	BUG_ON(old_left_nritems <= 0);

	btrfs_init_map_token(&token, left);
	old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
	for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
		u32 ioff;

		item = btrfs_item_nr(i);

		ioff = btrfs_token_item_offset(&token, item);
		btrfs_set_token_item_offset(&token, item,
		      ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size));
	}
	btrfs_set_header_nritems(left, old_left_nritems + push_items);

	 
	if (push_items > right_nritems)
		WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
		       right_nritems);

	if (push_items < right_nritems) {
		push_space = btrfs_item_offset_nr(right, push_items - 1) -
						  leaf_data_end(right);
		memmove_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET +
				      BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
				      BTRFS_LEAF_DATA_OFFSET +
				      leaf_data_end(right), push_space);

		memmove_extent_buffer(right, btrfs_item_nr_offset(0),
			      btrfs_item_nr_offset(push_items),
			     (btrfs_header_nritems(right) - push_items) *
			     sizeof(struct btrfs_item));
	}

	btrfs_init_map_token(&token, right);
	right_nritems -= push_items;
	btrfs_set_header_nritems(right, right_nritems);
	push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
	for (i = 0; i < right_nritems; i++) {
		item = btrfs_item_nr(i);

		push_space = push_space - btrfs_token_item_size(&token, item);
		btrfs_set_token_item_offset(&token, item, push_space);
	}

	btrfs_mark_buffer_dirty(left);
	if (right_nritems)
		btrfs_mark_buffer_dirty(right);
	else
		btrfs_clean_tree_block(right);

	btrfs_item_key(right, &disk_key, 0);
	fixup_low_keys(path, &disk_key, 1);

	 
	if (path->slots[0] < push_items) {
		path->slots[0] += old_left_nritems;
		btrfs_tree_unlock(path->nodes[0]);
		free_extent_buffer(path->nodes[0]);
		path->nodes[0] = left;
		path->slots[1] -= 1;
	} else {
		btrfs_tree_unlock(left);
		free_extent_buffer(left);
		path->slots[0] -= push_items;
	}
	BUG_ON(path->slots[0] < 0);
	return ret;
out:
	btrfs_tree_unlock(left);
	free_extent_buffer(left);
	return ret;
}