> I'd say "tries to handle"... gnu-tar can't distinguish between allocated blocks all zero
> and sparse holes. in case where it's important that some areas are really allocated,
> gnu-tar may break your files. might not be a common problem but tar just can't
> deal with sparse files perfectly; dump/restore can...
What about the bmap ioctl, FIBMAP?
Probably linux-specific, I'll grant.
pjm.