Merge branch 'linus' into core/rcu

1 files changed, 15 insertions, 9 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 35eebd5510c2..8185a0f09594 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -702,7 +702,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
 	 * any child cgroups exist. This is theoretically supportable
 	 * but involves complex error handling, so it's being left until
 	 * later */
-	if (!list_empty(&cgrp->children))
+	if (root->number_of_cgroups > 1)
 		return -EBUSY;
 
 	/* Process each subsystem */
@@ -2039,10 +2039,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
 	struct cgroup *cgrp;
 	struct cgroup_iter it;
 	struct task_struct *tsk;
+
 	/*
-	 * Validate dentry by checking the superblock operations
+	 * Validate dentry by checking the superblock operations,
+	 * and make sure it's a directory.
 	 */
-	if (dentry->d_sb->s_op != &cgroup_ops)
+	if (dentry->d_sb->s_op != &cgroup_ops ||
+	    !S_ISDIR(dentry->d_inode->i_mode))
 		 goto err;
 
 	ret = 0;
@@ -2472,10 +2475,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
 		mutex_unlock(&cgroup_mutex);
 		return -EBUSY;
 	}
-
-	parent = cgrp->parent;
-	root = cgrp->root;
-	sb = root->sb;
+	mutex_unlock(&cgroup_mutex);
 
 	/*
 	 * Call pre_destroy handlers of subsys. Notify subsystems
@@ -2483,7 +2483,14 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
 	 */
 	cgroup_call_pre_destroy(cgrp);
 
-	if (cgroup_has_css_refs(cgrp)) {
+	mutex_lock(&cgroup_mutex);
+	parent = cgrp->parent;
+	root = cgrp->root;
+	sb = root->sb;
+
+	if (atomic_read(&cgrp->count)
+	    || !list_empty(&cgrp->children)
+	    || cgroup_has_css_refs(cgrp)) {
 		mutex_unlock(&cgroup_mutex);
 		return -EBUSY;
 	}
@@ -2497,7 +2504,6 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
 	list_del(&cgrp->sibling);
 	spin_lock(&cgrp->dentry->d_lock);
 	d = dget(cgrp->dentry);
-	cgrp->dentry = NULL;
 	spin_unlock(&d->d_lock);
 
 	cgroup_d_remove_dir(d);