Wrong calculating of file size in du.py

[fremail]

It seems you have a bug in file size calculating for files bigger than block_size

elif os.path.isfile(dir_entry.path):
            file_size = os.path.getsize(dir_entry.path)
            if file_size > block_size:
                total_size += file_size

I think the total_size should be increased by size multiple of block_size.

Something like this:

total_size += math.ceil(file_size / block_size) * block_size