cgfsng: handle v1 cpuset hierarchy first

If the value of cgroup.clone_children in our immediate ancestor cgroup is 0 then the cpuset of any cgroups we create in subtrees will be empty and hence we'll copy an empty cpuset at which point we cannot enter the cpuset cgroup. Avoid this problem by initializing cgroup.clone_children to 1 an copying the initialized cpuset of our immediate ancestor. Note, that the cpuset of our immediate ancestor must be initialized and ours as well otherwise we couldn't be located in this cgroup. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

cgfsng: handle v1 cpuset hierarchy first
ef185360 · Christian Brauner · 6099dd5a · ef185360
Unverified Commit ef185360 authored Oct 03, 2018 by Christian Brauner
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cgfsng.c src/lxc/cgroups/cgfsng.c +10 -10

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--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -1297,6 +1297,11 @@ static bool monitor_create_path_for_hierarchy(struct hierarchy *h, char *cgname)
 {
 	int ret;

+	if (!cg_legacy_handle_cpuset_hierarchy(h, cgname)) {
+		ERROR("Failed to handle legacy cpuset controller");
+		return false;
+	}
+
 	h->monitor_full_path = must_make_path(h->mountpoint, h->container_base_path, cgname, NULL);
 	ret = mkdir_eexist_on_last(h->monitor_full_path, 0755);
 	if (ret < 0) {
@@ -1304,11 +1309,6 @@ static bool monitor_create_path_for_hierarchy(struct hierarchy *h, char *cgname)
 		return false;
 	}

-	if (!cg_legacy_handle_cpuset_hierarchy(h, cgname)) {
-		ERROR("Failed to handle legacy cpuset controller");
-		return false;
-	}
-
 	return cg_unified_create_cgroup(h, cgname);
 }

@@ -1316,6 +1316,11 @@ static bool container_create_path_for_hierarchy(struct hierarchy *h, char *cgnam
 {
 	int ret;

+	if (!cg_legacy_handle_cpuset_hierarchy(h, cgname)) {
+		ERROR("Failed to handle legacy cpuset controller");
+		return false;
+	}
+
 	h->container_full_path = must_make_path(h->mountpoint, h->container_base_path, cgname, NULL);
 	ret = mkdir_eexist_on_last(h->container_full_path, 0755);
 	if (ret < 0) {
@@ -1323,11 +1328,6 @@ static bool container_create_path_for_hierarchy(struct hierarchy *h, char *cgnam
 		return false;
 	}

-	if (!cg_legacy_handle_cpuset_hierarchy(h, cgname)) {
-		ERROR("Failed to handle legacy cpuset controller");
-		return false;
-	}
-
 	return cg_unified_create_cgroup(h, cgname);
 }