cgroup: warn if "xattr" is specified with "sane_behavior"

Mount option "xattr" is no longer necessary as it's enabled by default
on kernfs.  Warn if "xattr" is specified with "sane_behavior" so that
the option can be removed in the future.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 0e45a93..305e94e 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -264,6 +264,8 @@ enum {
         * - "release_agent" and "notify_on_release" are removed.
         *   Replacement notification mechanism will be implemented.
         *
+        * - "xattr" mount option is deprecated.  kernfs always enables it.
+        *
         * - cpuset: tasks will be kept in empty cpusets when hotplug happens
         *   and take masks of ancestors with non-empty cpus/mems, instead of
         *   being moved to an ancestor.

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index cda614d..a0fab71 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1267,6 +1267,9 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
                        pr_err("cgroup: sane_behavior: clone_children is not allowed\n");
                        return -EINVAL;
                }
+
+               if (opts->flags & CGRP_ROOT_XATTR)
+                       pr_warning("cgroup: sane_behavior: xattr is always available, flag unnecessary\n");
        }
 
        /*