On Wed, Dec 14, 2011 at 02:42:38PM -0500, Ric Wheeler wrote:

On 12/14/2011 02:27 PM, Al Viro wrote:

quoted

On Wed, Dec 14, 2011 at 02:22:07PM -0500, Ric Wheeler wrote:

quoted

We had an active thread a couple of years back that came out of the
reflink work and, at the time, there seemed to be moderately
positive support for adding a new system call that would fit this
use case (Joel Becker's copyfile()).

Can we resurrect this effort? Is copyfile() still a good way to go,
or should we look at other hooks?

copyfile(2) is probably a good way to go, provided that we do _not_
go baroque as it had happened the last time syscall had been discussed.

IOW, to hell with progress reports, etc. - just a fastpath kind of
thing, in the same kind of relationship to cp(1) as rename(2) is to mv(1).
If it works - fine, if not - caller has to be ready to deal with handling
cross-device case anyway.

I think that this approach makes a lot of sense. Most of the
devices/targets that support the copy offload, will do it in very
reasonable amounts of time.

Let me see if I can dig up some of the presentations from the NetApp
guys who presented overviews or the specifications from the IETF and
T10....

	Whee!  I've been down the rabbit hole, but I've promised myself
to get the updated patch out soon.  I know that Trond et al are probably
wondering what happened to the patch.  more soon.

Joel

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