Commit c7ba8287 authored Jun 29, 2013 by Tejun Heo

cgroup: CGRP_ROOT_SUBSYS_BOUND should also be ignored when mounting an existing hierarchy



0ce6cba3 ("cgroup: CGRP_ROOT_SUBSYS_BOUND should be ignored when
comparing mount options") only updated the remount path but
CGRP_ROOT_SUBSYS_BOUND should also be ignored when comparing options
while mounting an existing hierarchy.  As option mismatch triggers a
warning but doesn't fail the mount without sane_behavior, this only
triggers a spurious warning message.

Fix it by only comparing CGRP_ROOT_OPTION_MASK bits when comparing new
and existing root options.

Signed-off-by: Tejun Heo <tj@kernel.org>

parent 0ce6cba3

kernel/cgroup.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1703,7 +1703,7 @@ static struct dentry cgroup_mount(struct file_system_type fs_type,
	*/		*/
	cgroup_free_root(opts.new_root);		cgroup_free_root(opts.new_root);

	if (root->flags != opts.flags) {		if ((root->flags ^ opts.flags) & CGRP_ROOT_OPTION_MASK) {
	if ((root->flags \| opts.flags) & CGRP_ROOT_SANE_BEHAVIOR) {		if ((root->flags \| opts.flags) & CGRP_ROOT_SANE_BEHAVIOR) {
	pr_err("cgroup: sane_behavior: new mount options should match the existing superblock\n");		pr_err("cgroup: sane_behavior: new mount options should match the existing superblock\n");
	ret = -EINVAL;		ret = -EINVAL;