1 files changed, 39 insertions, 16 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 66a416b42c18..b24d7027b83c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -764,6 +764,7 @@ EXPORT_SYMBOL_GPL(cgroup_unlock);
  */
 
 static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode);
+static struct dentry *cgroup_lookup(struct inode *, struct dentry *, struct nameidata *);
 static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
 static int cgroup_populate_dir(struct cgroup *cgrp);
 static const struct inode_operations cgroup_dir_inode_operations;
@@ -860,6 +861,11 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
         iput(inode);
 }
 
+static int cgroup_delete(const struct dentry *d)
+{
+        return 1;
+}
+
 static void remove_dir(struct dentry *d)
 {
         struct dentry *parent = dget(d->d_parent);
@@ -874,25 +880,29 @@ static void cgroup_clear_directory(struct dentry *dentry)
         struct list_head *node;
 
         BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
-        spin_lock(&dcache_lock);
+        spin_lock(&dentry->d_lock);
         node = dentry->d_subdirs.next;
         while (node != &dentry->d_subdirs) {
                 struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
+
+                spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
                 list_del_init(node);
                 if (d->d_inode) {
                         /* This should never be called on a cgroup
                          * directory with child cgroups */
                         BUG_ON(d->d_inode->i_mode & S_IFDIR);
-                        d = dget_locked(d);
-                        spin_unlock(&dcache_lock);
+                        dget_dlock(d);
+                        spin_unlock(&d->d_lock);
+                        spin_unlock(&dentry->d_lock);
                         d_delete(d);
                         simple_unlink(dentry->d_inode, d);
                         dput(d);
-                        spin_lock(&dcache_lock);
-                }
+                        spin_lock(&dentry->d_lock);
+                } else
+                        spin_unlock(&d->d_lock);
                 node = dentry->d_subdirs.next;
         }
-        spin_unlock(&dcache_lock);
+        spin_unlock(&dentry->d_lock);
 }
 
 /*
@@ -900,11 +910,16 @@ static void cgroup_clear_directory(struct dentry *dentry)
  */
 static void cgroup_d_remove_dir(struct dentry *dentry)
 {
+        struct dentry *parent;
+
         cgroup_clear_directory(dentry);
 
-        spin_lock(&dcache_lock);
+        parent = dentry->d_parent;
+        spin_lock(&parent->d_lock);
+        spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
         list_del_init(&dentry->d_u.d_child);
-        spin_unlock(&dcache_lock);
+        spin_unlock(&dentry->d_lock);
+        spin_unlock(&parent->d_lock);
         remove_dir(dentry);
 }
 
@@ -1440,6 +1455,11 @@ static int cgroup_set_super(struct super_block *sb, void *data)
 
 static int cgroup_get_rootdir(struct super_block *sb)
 {
+        static const struct dentry_operations cgroup_dops = {
+                .d_iput = cgroup_diput,
+                .d_delete = cgroup_delete,
+        };
+
         struct inode *inode =
                 cgroup_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR, sb);
         struct dentry *dentry;
@@ -1457,6 +1477,8 @@ static int cgroup_get_rootdir(struct super_block *sb)
                 return -ENOMEM;
         }
         sb->s_root = dentry;
+        /* for everything else we want ->d_op set */
+        sb->s_d_op = &cgroup_dops;
         return 0;
 }
 
@@ -2180,12 +2202,20 @@ static const struct file_operations cgroup_file_operations = {
 };
 
 static const struct inode_operations cgroup_dir_inode_operations = {
-        .lookup = simple_lookup,
+        .lookup = cgroup_lookup,
         .mkdir = cgroup_mkdir,
         .rmdir = cgroup_rmdir,
         .rename = cgroup_rename,
 };
 
+static struct dentry *cgroup_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+        if (dentry->d_name.len > NAME_MAX)
+                return ERR_PTR(-ENAMETOOLONG);
+        d_add(dentry, NULL);
+        return NULL;
+}
+
 /*
  * Check if a file is a control file
  */
@@ -2199,10 +2229,6 @@ static inline struct cftype *__file_cft(struct file *file)
 static int cgroup_create_file(struct dentry *dentry, mode_t mode,
                                 struct super_block *sb)
 {
-        static const struct dentry_operations cgroup_dops = {
-                .d_iput = cgroup_diput,
-        };
-
         struct inode *inode;
 
         if (!dentry)
@@ -2228,7 +2254,6 @@ static int cgroup_create_file(struct dentry *dentry, mode_t mode,
                 inode->i_size = 0;
                 inode->i_fop = &cgroup_file_operations;
         }
-        dentry->d_op = &cgroup_dops;
         d_instantiate(dentry, inode);
         dget(dentry);   /* Extra count - pin the dentry in core */
         return 0;
@@ -3638,9 +3663,7 @@ again:
         list_del(&cgrp->sibling);
         cgroup_unlock_hierarchy(cgrp->root);
 
-        spin_lock(&cgrp->dentry->d_lock);
         d = dget(cgrp->dentry);
-        spin_unlock(&d->d_lock);
 
         cgroup_d_remove_dir(d);
         dput(d);