Messages in this thread | | | Date | Tue, 1 Dec 2015 15:58:53 -0600 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 7/8] cgroup: mount cgroupns-root when inside non-init cgroupns |
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On Tue, Dec 01, 2015 at 11:46:49AM -0500, Tejun Heo wrote: > Hey, Serge. > > On Mon, Nov 30, 2015 at 10:07:04PM -0600, Serge E. Hallyn wrote: > > So actually the way the code is now, the first mount cannot > > be done from a non-init user namespace; and kernfs_obtain_root() > > is only called from non-init user namespace. So can we assume > > that the root dentry will be instantiated? (or can it get > > evicted?) > > > > If we can assume that then most of that fn can go away. > > The v2 hierarchy is always mounted and non-init ns shouldn't be able > to create new v1 hierarchies, so the root dentry should always be > there.
I mispoke before though - it's not the hierarchy's root dentry, but rather a dentry for a descendent cgroup which will become the root dentry for the new superblock. We do know that there must be a css_set with a cgroup. I'm still trying to track down whether that cgrou's inode's dentry can ever be flushed. I would think not but am not sure.
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