cgroup: update cgroup_create() failure path

cgroup_create() was ignoring failure of cgroupfs files.  Update it
such that, if file creation fails, it rolls back by calling
cgroup_destroy_locked() and returns failure.

Note that error out goto labels are renamed.  The labels are a bit
confusing but will become better w/ later cgroup operation renames.

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 c53f42e..027b66e 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4107,7 +4107,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
         */
        if (!cgroup_lock_live_group(parent)) {
                err = -ENODEV;
-               goto err_free;
+               goto err_free_cgrp;
        }
 
        /* Grab a reference on the superblock so the hierarchy doesn't
@@ -4135,13 +4135,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
                css = ss->create(cgrp);
                if (IS_ERR(css)) {
                        err = PTR_ERR(css);
-                       goto err_destroy;
+                       goto err_free_all;
                }
                init_cgroup_css(css, ss, cgrp);
                if (ss->use_id) {
                        err = alloc_css_id(ss, parent, cgrp);
                        if (err)
-                               goto err_destroy;
+                               goto err_free_all;
                }
                /* At error, ->destroy() callback has to free assigned ID. */
                if (clone_children(parent) && ss->post_clone)
@@ -4164,7 +4164,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
         */
        err = cgroup_create_file(dentry, S_IFDIR | mode, sb);
        if (err < 0)
-               goto err_destroy;
+               goto err_free_all;
        lockdep_assert_held(&dentry->d_inode->i_mutex);
 
        /* allocation complete, commit to creation */
@@ -4183,14 +4183,15 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
        }
 
        err = cgroup_populate_dir(cgrp, true, root->subsys_mask);
-       /* If err < 0, we have a half-filled directory - oh well ;) */
+       if (err)
+               goto err_destroy;
 
        mutex_unlock(&cgroup_mutex);
        mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
 
        return 0;
 
-err_destroy:
+err_free_all:
        for_each_subsys(root, ss) {
                if (cgrp->subsys[ss->subsys_id])
                        ss->destroy(cgrp);
@@ -4198,9 +4199,15 @@ err_destroy:
        mutex_unlock(&cgroup_mutex);
        /* Release the reference count that we took on the superblock */
        deactivate_super(sb);
-err_free:
+err_free_cgrp:
        kfree(cgrp);
        return err;
+
+err_destroy:
+       cgroup_destroy_locked(cgrp);
+       mutex_unlock(&cgroup_mutex);
+       mutex_unlock(&dentry->d_inode->i_mutex);
+       return err;
 }
 
 static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)