Re: xattr names for unprivileged stacking?

Al Viro
2020-08-29T16:14:12Z

On Sat, Aug 29, 2020 at 05:07:17PM +0100, Matthew Wilcox wrote:

> I agree with you that supporting named streams within a file requires
> an independent inode for each stream. I disagree with you that this is
> dentry cache infrastructure. I do not believe in giving each stream
> its own dentry. Either they share the default stream's dentry, or they
> have no dentry (mild preference for no dentry).

*blink*

Just how would they have different inodes while sharing a dentry?

> > The fact that ADS inodes would not be in the dentry cache and hence
> > not visible to pathwalks at all then means that all of the issues
> > such as mounting over them, chroot, etc don't exist in the first
> > place...
>
> Wait, you've now switched from "this is dentry cache infrastructure"
> to "it should not be in the dentry cache". So I don't understand what
> you're arguing for.

Bloody wonderful, that. So now we have struct file instances with no dentry
associated with them? Which would have to be taken into account all over
the place...