[PATCHv2 7/7] cgroup: mount cgroupns-root when inside non-init cgroupns

[Eric W. Biederman]

Andy Lutomirski <luto at amacapital.net> writes:
>> @@ -1862,6 +1904,7 @@ static struct file_system_type cgroup_fs_type = {
>>         .name = "cgroup",
>>         .mount = cgroup_mount,
>>         .kill_sb = cgroup_kill_sb,
>> +       .fs_flags = FS_USERNS_MOUNT,
>
> Aargh, another one!  Eric, can you either ack or nack my patch?
> Because if my patch goes in, then this line may need to change.  Or
> not, but if a stable release with cgroupfs and without my patch
> happens, then we'll have an ABI break.

cgroupfs has no device nodes.  So as long as we are consistent in any
given release what happens here is orthogonal.

I don't remember if we have managed to get the original problem fixed
with the trivial backportable solution.  I think so.

My apologies for not getting to that I haven't even had time to shepherd
through the regression associated regression fix.  I probably just lock
track of them but I haven't found the Tested-By's for it yet.

Nor have I had time to dig through and figure out how to safely deal
with umount -l aka MOUNT_DETACH.

Along with the question about what to do with nodev, there is also
your patch about nosuid.

Starting in about 5 minutes I am going to be mostly offline until
sometime in the 3rd week in November as I haul all of my stuff accross
the country to someplace that actually has winter and my allergies don't
kill me.

I am going to have to review and merge a lot of code as soon as I am
back to being a programmer full time again.  There is a lot of
interesting stuff coming in right now.

Eric