file metadata via fs API (was: [GIT PULL] Filesystem Information)

[Miklos Szeredi]

On Wed, Aug 12, 2020 at 4:40 PM Al Viro <viro at zeniv.linux.org.uk> wrote:
>
> On Wed, Aug 12, 2020 at 09:23:23AM +0200, Miklos Szeredi wrote:
>
> > Anyway, starting with just introducing the alt namespace without
> > unification seems to be a good first step. If that turns out to be
> > workable, we can revisit unification later.
>
> Start with coming up with answers to the questions on semantics
> upthread.  To spare you the joy of digging through the branches
> of that thread, how's that for starters?
>
> "Can those suckers be passed to
> ...at() as starting points?

No.

>  Can they be bound in namespace?

No.

> Can something be bound *on* them?

No.

>  What do they have for inodes
> and what maintains their inumbers (and st_dev, while we are at
> it)?

Irrelevant.  Can be some anon dev + shared inode.

The only attribute of an attribute that I can think of that makes
sense would be st_size, but even that is probably unimportant.

>  Can _they_ have secondaries like that (sensu Swift)?

Reference?

> Is that a flat space, or can they be directories?"

Yes it has a directory tree.   But you can't mkdir, rename, link,
symlink, etc on anything in there.

Thanks,
Miklos