cgroup: update error handling in cgroup_populate_dir()
cgroup_populate_dir() didn't use to check whether the actual file
creations were successful and could return success with only subset of
the requested files created, which is nasty.
This patch udpates cgroup_populate_dir() so that it either succeeds
with all files or fails with no file.
v2: The original patch also converted for_each_root_subsys() usages to
for_each_subsys() without explaining why. That part has been
moved to a separate patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 9835a09..6b73244 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4171,10 +4171,13 @@
* cgroup_populate_dir - create subsys files in a cgroup directory
* @cgrp: target cgroup
* @subsys_mask: mask of the subsystem ids whose files should be added
+ *
+ * On failure, no file is added.
*/
static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask)
{
struct cgroup_subsys *ss;
+ int ret = 0;
/* process cftsets of each subsystem */
for_each_root_subsys(cgrp->root, ss) {
@@ -4182,8 +4185,11 @@
if (!test_bit(ss->subsys_id, &subsys_mask))
continue;
- list_for_each_entry(set, &ss->cftsets, node)
- cgroup_addrm_files(cgrp, ss, set->cfts, true);
+ list_for_each_entry(set, &ss->cftsets, node) {
+ ret = cgroup_addrm_files(cgrp, ss, set->cfts, true);
+ if (ret < 0)
+ goto err;
+ }
}
/* This cgroup is ready now */
@@ -4201,6 +4207,9 @@
}
return 0;
+err:
+ cgroup_clear_dir(cgrp, subsys_mask);
+ return ret;
}
static void css_dput_fn(struct work_struct *work)