Re: Introspecting userns relationships to other namespaces?
From: Eric W. Biederman
Date: Fri Jul 08 2016 - 23:25:52 EST
"W. Trevor King" <wking@xxxxxxxxxx> writes:
> On Thu, Jul 07, 2016 at 08:01:52AM -0700, James Bottomley wrote:
>> In theory, we could get nsfs to show this information as an option
>> (just add a show_options entry to the superblock ops), but the
>> problem is that although each namespace has a parent user_ns,
>> there's no way to get it without digging in the namespace specific
>> structure. Probably we should restructure to move it into
>> ns_common, then we could display it (and enforce all namespaces
>> having owning user_ns) but it would be a reasonably large (but
>> mechanical) change.
> It sounds like everyone is either positive or or neutral on this
> groundwork, even if we haven't decided if/how to expose the
> information to userspace. I'm happy to work up a patch while the rest
> of the discussion continues. I'm also happy to let someone else work
> up the patch, if anyone else is chomping at the bit ;).
I am dubious on moving all of the user namespace members into ns_common.
I would happy to be proved wrong but I suspect in the cases where we
actually use that user namespace the code will become uglier. Making
the ordinary uses uglier to make a rare corner case nicer is the wrong
But feel free to try it is certainly worth doing if it doesn't make the
code that uses the user namespaces uglier.