Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin

* 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits)
  fs: scale mntget/mntput
  fs: rename vfsmount counter helpers
  fs: implement faster dentry memcmp
  fs: prefetch inode data in dcache lookup
  fs: improve scalability of pseudo filesystems
  fs: dcache per-inode inode alias locking
  fs: dcache per-bucket dcache hash locking
  bit_spinlock: add required includes
  kernel: add bl_list
  xfs: provide simple rcu-walk ACL implementation
  btrfs: provide simple rcu-walk ACL implementation
  ext2,3,4: provide simple rcu-walk ACL implementation
  fs: provide simple rcu-walk generic_check_acl implementation
  fs: provide rcu-walk aware permission i_ops
  fs: rcu-walk aware d_revalidate method
  fs: cache optimise dentry and inode for rcu-walk
  fs: dcache reduce branches in lookup path
  fs: dcache remove d_mounted
  fs: fs_struct use seqlock
  fs: rcu-walk for path lookup
  ...

1 files changed, 39 insertions, 15 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 66a416b42c18..51cddc11cd85 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -763,6 +763,8 @@ EXPORT_SYMBOL_GPL(cgroup_unlock);
  * -> cgroup_mkdir.
  */
 
+static struct dentry *cgroup_lookup(struct inode *dir,
+                        struct dentry *dentry, struct nameidata *nd);
 static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode);
 static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
 static int cgroup_populate_dir(struct cgroup *cgrp);
@@ -874,25 +876,29 @@ 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 +906,16 @@ 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(&dentry->d_lock);
         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);
 }
 
@@ -2180,7 +2191,7 @@ 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,
@@ -2196,13 +2207,29 @@ static inline struct cftype *__file_cft(struct file *file)
         return __d_cft(file->f_dentry);
 }
 
-static int cgroup_create_file(struct dentry *dentry, mode_t mode,
-                                struct super_block *sb)
+static int cgroup_delete_dentry(const struct dentry *dentry)
+{
+        return 1;
+}
+
+static struct dentry *cgroup_lookup(struct inode *dir,
+                        struct dentry *dentry, struct nameidata *nd)
 {
-        static const struct dentry_operations cgroup_dops = {
+        static const struct dentry_operations cgroup_dentry_operations = {
+                .d_delete = cgroup_delete_dentry,
                 .d_iput = cgroup_diput,
         };
 
+        if (dentry->d_name.len > NAME_MAX)
+                return ERR_PTR(-ENAMETOOLONG);
+        d_set_d_op(dentry, &cgroup_dentry_operations);
+        d_add(dentry, NULL);
+        return NULL;
+}
+
+static int cgroup_create_file(struct dentry *dentry, mode_t mode,
+                                struct super_block *sb)
+{
         struct inode *inode;
 
         if (!dentry)
@@ -2228,7 +2255,6 @@ 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 +3664,7 @@ 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);