Commit 8b5a5a9d authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: deprecate remount option changes 



This patch marks the following features for deprecation.

* Rebinding subsys by remount: Never reached useful state - only works
  on empty hierarchies.

* release_agent update by remount: release_agent itself will be
  replaced with conventional fsnotify notification.

v2: Lennart pointed out that "name=" is necessary for mounts w/o any
    controller attached.  Drop "name=" deprecation.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
parent dd775ae2

Documentation/feature-removal-schedule.txt

+9 −0
Original line number Diff line number Diff line
@@ -539,3 +539,12 @@ Why: There appear to be no production users of the get_robust_list syscall, 
	of ASLR. It was only ever intended for debugging, so it should be

	removed.

Who:	Kees Cook <keescook@chromium.org>



----------------------------



What:	cgroup option updates via remount

When:	March 2013

Why:	Remount currently allows changing bound subsystems and

	release_agent.  Rebinding is hardly useful as it only works

	when the hierarchy is empty and release_agent itself should be

	replaced with conventional fsnotify.

kernel/cgroup.c

+5 −0
Original line number Diff line number Diff line
@@ -1294,6 +1294,11 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data) 
	if (ret)

		goto out_unlock;



	/* See feature-removal-schedule.txt */

	if (opts.subsys_bits != root->actual_subsys_bits || opts.release_agent)

		pr_warning("cgroup: option changes via remount are deprecated (pid=%d comm=%s)\n",

			   task_tgid_nr(current), current->comm);



	/* Don't allow flags or name to change at remount */

	if (opts.flags != root->flags ||

	    (opts.name && strcmp(opts.name, root->name))) {

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