> > - why "share" rather than "export"?
> 
> I chose "share" because "export" is too tightly coupled with NFS. However, I'm
> sure my point of view can be swayed ;-)

it's actually tightly coupled with nfs, isn't it?
eg. how can it prevent smbd or apache from exporting the filesystem?

> > - what's the point to expose it as a mount option?
> >   sys_mount is not an appropriate interface to control nfs exportability
> >   these days.  to specify filesystem characteristics,
> >   IMNT_ is more appropriate.
> 
> I'm exposing it as a mount option so that userland knows it's there. It's a
> clear indicater of _why_ exporting doesn't work, "noshare" (or "noexport") can
> be seen from the mount options.

i believe that mount is a wrong way to show this kind of
filesystem characteristics.

YAMAMOTO Takashi