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

On Tue, Aug 4, 2020 at 4:36 PM Miklos Szeredi [off-list ref] wrote:

I think we already lost that with the xattr API, that should have been
done in a way that fits this philosophy.  But given that we  have "/"
as the only special purpose char in filenames, and even repetitions
are allowed, it's hard to think of a good way to do that.  Pity.

One way this could be solved is to allow opting into an alternative
path resolution mode.

E.g.
  openat(AT_FDCWD, "foo/bar//mnt/info", O_RDONLY | O_ALT);

Yes, the implementation might be somewhat tricky, but that's another
question.  Also I'm pretty sure that we should be reducing the
POSIX-ness of anything below "//" to the bare minimum.  No seeking,
etc....

I think this would open up some nice possibilities beyond the fsinfo thing.

Thanks,
Miklos