nilfs_last_byte
limit = kaddr + nilfs_last_byte(inode, n) -
kaddr += nilfs_last_byte(dir, n) - reclen;
limit = nilfs_last_byte(dir, 0); /* is a multiple of chunk size */
dir_end = kaddr + nilfs_last_byte(dir, n);
kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);