int ext4_readpage_inline(struct inode *inode, struct page *page)
{
	int ret = 0;

	down_read(&EXT4_I(inode)->xattr_sem);
	if (!ext4_has_inline_data(inode)) {
		up_read(&EXT4_I(inode)->xattr_sem);
		return -EAGAIN;
	}

	/*
	 * Current inline data can only exist in the 1st page,
	 * So for all the other pages, just set them uptodate.
	 */
	if (!page->index)
		ret = ext4_read_inline_page(inode, page);
	else if (!PageUptodate(page)) {
		zero_user_segment(page, 0, PAGE_SIZE);
		SetPageUptodate(page);
	}

	up_read(&EXT4_I(inode)->xattr_sem);

	unlock_page(page);
	return ret >= 0 ? 0 : ret;
}
Unknown