lua in zfs

[Warner Losh]

On Thu, Sep 28, 2017 at 11:52 AM, John Baldwin <jhb at freebsd.org> wrote:

> On Thursday, September 28, 2017 11:07:35 AM Warner Losh wrote:
> > On Thu, Sep 28, 2017 at 10:50 AM, Andriy Gapon <avg at freebsd.org> wrote:
> >
> > > On 28/09/2017 19:44, Andriy Gapon wrote:
> > > > On 28/09/2017 18:55, Ian Lepore wrote:
> > > >> Iirc, the big difference between 5.2.x and 5.3 is that the latter
> added
> > > >> support for integers.  It seems like that would be a good thing, in
> the
> > > >> kernel.
> > > >
> > > > I am sure that the ZFS Lua represents numbers as integers and has no
> > > floating
> > > > point support at all.
> > >
> > >
> > > Some more info:
> > > https://github.com/illumos/illumos-gate/blob/master/usr/
> > > src/uts/common/fs/zfs/lua/README.zfs
> >
> >
> > Reading this strongly suggests to me that we're going to have two
> versions
> > of lua in the tree then:
> >
> > 1) This version is a modified version of 5.2.4
> > 2) Significant changes have been made to harden this interpreter, which
> > won't be in 5.3.0
> > 3) A number of APIs have been removed, which makes it difficult to use
> as a
> > general purpose thing.
> >
> > So I think that you should go ahead and import it. The level of work for
> my
> > request is very high, and significantly diverges us from upstream. It's
> > unfortunate that we'll have two versions. But this isn't really pure lua
> > but a variant maybe better described as lua-zfs.
>
> Yes, that was my guess from Andriy's original e-mail.  ZFS tends to be a
> bit
> self-contained and includes its own version of zlib for example.  In
> general
> it seems to use its own version of 3rd party utils rather than sharing
> those
> with other parts of the system.
>

Sure. I was vaguely aware of that...  But I had to ask to make sure that we
couldn't use it, and also provide a 'paper trail' to those grepping the
tree / mailing lists for why...

Warner