Re: [PATCH v2] xattr: Enable security.capability in user namespaces

[Serge E. Hallyn]

Quoting Stefan Berger (stefanb@xxxxxxxxxxxxxxxxxx):
> For virtualizing the xattrs on the 'value' side I was looking for
> whether there's something like a 'wrapper' structure around the
> actual value of the xattr so that that wrapper could be extended to
> support different values at different uids and applied to any xattr.
> Unfortunately there's no such 'wrapper'.

I believe my very first implementation did essentially this - it used
the not uncommon structure of (mostly making this up):

struct ns_vfs_cap {
	int magic;
	int ncaps;
	struct ns_vfs_cap_data data[0];
};

with (ncaps * sizeof(ns_vfs_cap_data)) following that.

I didn't like it.

-serge