struct page *get_new_data_page(struct inode *inode,
		struct page *ipage, pgoff_t index, bool new_i_size)
{
	struct address_space *mapping = inode->i_mapping;
	struct page *page;
	struct dnode_of_data dn;
	int err;

	page = f2fs_grab_cache_page(mapping, index, true);
	if (!page) {
		/*
		 * before exiting, we should make sure ipage will be released
		 * if any error occur.
		 */
		f2fs_put_page(ipage, 1);
		return ERR_PTR(-ENOMEM);
	}

	set_new_dnode(&dn, inode, ipage, NULL, 0);
	err = f2fs_reserve_block(&dn, index);
	if (err) {
		f2fs_put_page(page, 1);
		return ERR_PTR(err);
	}
	if (!ipage)
		f2fs_put_dnode(&dn);

	if (PageUptodate(page))
		goto got_it;

	if (dn.data_blkaddr == NEW_ADDR) {
		zero_user_segment(page, 0, PAGE_SIZE);
		if (!PageUptodate(page))
			SetPageUptodate(page);
	} else {
		f2fs_put_page(page, 1);

		/* if ipage exists, blkaddr should be NEW_ADDR */
		f2fs_bug_on(F2FS_I_SB(inode), ipage);
		page = get_lock_data_page(inode, index, true);
		if (IS_ERR(page))
			return page;
	}
got_it:
	if (new_i_size && i_size_read(inode) <
				((loff_t)(index + 1) << PAGE_SHIFT))
		f2fs_i_size_write(inode, ((loff_t)(index + 1) << PAGE_SHIFT));
	return page;
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.