On Wed, Dec 02, 2015 at 11:53:12AM -0500, Tejun Heo wrote:

Hello, Serge.

On Tue, Dec 01, 2015 at 03:58:53PM -0600, Serge E. Hallyn wrote:

quoted

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.

Hmmm... I'm not really following.  The inode can be flushed and that's
why it needs to be walked down from root.  What am I missing here?

Can it be flushed when we know that the cgroup is being pinned by
a css_set?  (There's either a task or a cgroup_namespace pinning it
or we wouldn't get here)

-serge