[Devel] [PATCH VZ8 v1 13/14] ve/cgroup: At cgroup_mark(unmark)_ve_roots skip non-virtualized roots

[Valeriy Vdovin]

During container start there might be a situation when not all cgroup
hierarchies get virtualized by container manager (like vzctl). By
virtualizing a cgroup hierarchy I mean creation of sub-directory within
a particular mounted cgroup. When container starts it looks in css set
of it's init process to list all affilated cgroups and perform actions
on each. But non-virtualized cgroups will also be present in init's css_set
and they should not be touched from inside of any non root ve.

Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
---
 kernel/cgroup/cgroup.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 285e84d1150f..34e049361611 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1927,6 +1927,23 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
 			   struct cftype *cft, bool activate);
 
 #ifdef CONFIG_VE
+static inline bool is_virtualized_cgroup(struct cgroup *cgrp)
+{
+	/*
+	 * no parent means this is the host cgroup
+	 */
+	if (!cgrp->kn->parent)
+		return false;
+
+	if (cgrp->root->subsys_mask)
+		return true;
+
+	if (!strcmp(cgrp->root->name, "systemd"))
+		return true;
+
+	return false;
+}
+
 int cgroup_mark_ve_roots(struct ve_struct *ve)
 {
 	int err;
-- 
2.27.0