Re: cp --sparse might corrupt DEST

[Szakacsits Szabolcs]

On Mon, 8 Mar 2004, Jim Meyering wrote:
> 
> Changing cp as you suggest is one way to solve this problem.
> Another would be to make cp fail when it's asked to do
> something that doesn't make sense: preserve holes in a
> non-regular destination file.

I think the later one isn't correct:

   1) it's not cp's job to preserve holes. It's an optimization
      but it can not be done _always_.

   2) people suppose cp works in the non-regular destination 
      file case. This would get broken with the later change.

BTW, if you're interested in large sparse file handling optimization 
(cp, cat, etc) currently having horrible performance (coredumps, sparse
matrices, etc) then you might take a look at the relevant part (HANDLING 
LARGE SPARSE FILES) of

        http://linux-ntfs.sourceforge.net/man/ntfsclone.html

    Szaka