Re: cross-subvolume cp --reflink

On Mon, Aug 20, 2012 at 11:08 AM, Jérôme Poulin <jeromepoulin <at> gmail.com> wrote:
>
> On Thu, Aug 16, 2012 at 5:41 PM, james northrup
> <northrup.james <at> gmail.com> wrote:
> >
> > dunno if this thread is dead, but im inclined to patch in cp --reflink
> > to "fdupes" prog.
> >  It  currently does provide a poor-man's dedupe via md5sum and hardlink,
> > or delete.
> >
> > all the better if the distro-kernels can backport cross-snapshot
> > reflinks sooner than later.
> >
>
> I was also wondering if it is possible for a program like fdupes to
> use BTRFS checksum to make searching for duplicates much faster as you
> wouldn't need to calculate checksum if BTRFS own checksum was
> mismatched between 2 groups of checksum blocks?

source in question is here..

http://code.google.com/p/fdupes/source/browse/trunk/fdupes.c

i consider cp --reflink an option for this code.  it doesn't strike me
as scalable at first glance and i wouldnt want to spend more than a
few minutes adding a  new option.

i like the idea of something a little more scalable to populate a
radix tree with extent-checksums abound and to link them without
regard to order or associative. i dont have this project in mind