int nilfs_ifile_read(struct super_block *sb, struct nilfs_root *root,
		     size_t inode_size, struct nilfs_inode *raw_inode,
		     struct inode **inodep)
int nilfs_ifile_read(struct super_block *sb, struct nilfs_root *root,
		     __u64 cno, size_t inode_size)