static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
{
	struct extent_io_tree *tree;


	if (current->flags & PF_MEMALLOC) {
		redirty_page_for_writepage(wbc, page);
		unlock_page(page);
		return 0;
	}
	tree = &BTRFS_I(page->mapping->host)->io_tree;
	return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
}
static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
{
	struct extent_io_tree *tree;


	if (current->flags & PF_MEMALLOC) {
		redirty_page_for_writepage(wbc, page);
		unlock_page(page);
		return 0;
	}
	tree = &BTRFS_I(page->mapping->host)->io_tree;
	return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
}