Re: Supporting reflinked/cow files in coreutils

[Philipp Thomas]

* Pádraig Brady (address@hidden) [20110414 17:30]:

> I don't think there is anything else you could do,
> like minimizing reads from a set of files with
> shared extents, as there is no way to ID the extent.
> Oh I suppose you could by using device_id, physical_offset.
> You could extend the di_set stuff we have for matching
> hardlinks to do that I suppose. But then one can currently
> only clone a file, not an extent (on BTRFS at least).
> What is your use case exactly?

As far as I understood the request, it's for reflink support in du so that
it's possible to see the space savings reflinks give you. Given your hint
I'll have a look at the di_set stuff to see how this can possibly be
extended to use the FIEMAP info.

> Also it would be better to send details to address@hidden
> as others might have suggestions.

Which I'm doing hereby. BTW, could somebody point me to the documents for
copyright assignment? I have one on file for GCC but now I'd need one for
coreutils.

Philpp