Re: [PATCH][RFC] fast file mapping for loop

Chris Mason
2008-01-10T12:49:21Z

On Thu, 10 Jan 2008 09:31:31 +0100
Jens Axboe <jens.axboe@oracle.com> wrote:

> On Wed, Jan 09 2008, Alasdair G Kergon wrote:
> > Here's the latest version of dm-loop, for comparison.
> >
> > To try it out,
> > ln -s dmsetup dmlosetup
> > and supply similar basic parameters to losetup.
> > (using dmsetup version 1.02.11 or higher)
>
> Why oh why does dm always insist to reinvent everything? That's bad
> enough in itself, but on top of that most of the extra stuff ends up
> being essentially unmaintained.

I don't quite get how the dm version is reinventing things. They use
the dmsetup command that they use for everything else and provide a
small and fairly clean module for bio specific loop instead of piling
it onto loop.c....

Their code doesn't have the fancy hole handling that yours does, but
neither did yours 4 days ago ;)

>
> If we instead improve loop, everyone wins.
>
> Sorry to sound a bit harsh, but sometimes it doesn't hurt to think a
> bit outside your own sandbox.
>

It is a natural fit in either place, as both loop and dm have a good
infrastructure for it. I'm not picky about where it ends up, but dm
wouldn't be a bad place.

-chris