diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 698ae80..f877411 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -599,7 +599,7 @@ function block_form_user_profile_form_alter(&$form, &$form_state) {
   $account = $form_state['controller']->getEntity($form_state);
   $rids = array_keys($account->roles);
   $result = db_query("SELECT DISTINCT b.* FROM {block} b LEFT JOIN {block_role} r ON b.module = r.module AND b.delta = r.delta WHERE b.status = 1 AND b.custom <> 0 AND (r.rid IN (:rids) OR r.rid IS NULL) ORDER BY b.weight, b.module", array(':rids' => $rids));
-  $account_data = user_data_get('block', $account->uid, 'block');
+  $account_data = drupal_container()->get('user.data')->get('block', $account->uid, 'block');
 
   $blocks = array();
   foreach ($result as $block) {
@@ -644,7 +644,7 @@ function block_field_extra_fields() {
  */
 function block_user_update($account) {
   if (isset($account->block)) {
-    user_data_set('block', $account->uid, 'block', $account->block);
+    drupal_container()->get('user.data')->set('block', $account->uid, 'block', $account->block);
   }
 }
 
@@ -807,7 +807,7 @@ function block_block_list_alter(&$blocks) {
   }
 
   if ($user->uid) {
-    $user_data = user_data_get('block', $user->uid, 'block');
+    $user_data = drupal_container()->get('user.data')->get('block', $user->uid, 'block');
   }
 
   foreach ($blocks as $key => $block) {
diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index 5b191ec..d74a66a 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -144,7 +144,7 @@ function _contact_personal_tab_access($account) {
 
   // If the requested user has disabled their contact form, do not allow users
   // to contact them.
-  $account_data = user_data_get('contact', $account->uid, 'enabled');
+  $account_data = drupal_container()->get('user.data')->get('contact', $account->uid, 'enabled');
   if (isset($account_data) && empty($account_data)) {
     return FALSE;
   }
@@ -293,7 +293,7 @@ function contact_form_user_profile_form_alter(&$form, &$form_state) {
     '#collapsible' => TRUE,
   );
   $account = $form_state['controller']->getEntity($form_state);
-  $account_data = user_data_get('contact', $account->uid, 'enabled');
+  $account_data = drupal_container()->get('user.data')->get('contact', $account->uid, 'enabled');
   $form['contact']['contact'] = array(
     '#type' => 'checkbox',
     '#title' => t('Personal contact form'),
@@ -307,7 +307,7 @@ function contact_form_user_profile_form_alter(&$form, &$form_state) {
  */
 function contact_user_update($account) {
   if (isset($account->contact)) {
-    user_data_set('contact', $account->uid, 'enabled', (int) $account->contact);
+    drupal_container()->get('user.data')->set('contact', $account->uid, 'enabled', (int) $account->contact);
   }
 }
 
diff --git a/core/modules/overlay/overlay.module b/core/modules/overlay/overlay.module
index 0380849..76d90be 100644
--- a/core/modules/overlay/overlay.module
+++ b/core/modules/overlay/overlay.module
@@ -87,7 +87,7 @@ function overlay_theme() {
 function overlay_form_user_profile_form_alter(&$form, &$form_state) {
   $account = $form_state['controller']->getEntity($form_state);
   if (user_access('access overlay', $account)) {
-    $account_data = user_data_get('overlay', $account->uid, 'enabled');
+    $account_data = drupal_container()->get('user.data')->get('overlay', $account->uid, 'enabled');
     $form['overlay_control'] = array(
       '#type' => 'fieldset',
       '#title' => t('Administrative overlay'),
@@ -108,7 +108,7 @@ function overlay_form_user_profile_form_alter(&$form, &$form_state) {
  */
 function overlay_user_presave($account) {
   if (isset($account->overlay)) {
-    user_data_set('overlay', $account->uid, 'enabled', $account->overlay);
+    drupal_container()->get('user.data')->set('overlay', $account->uid, 'enabled', $account->overlay);
   }
 }
 
@@ -127,7 +127,7 @@ function overlay_init() {
 
   // Only act if the user has access to the overlay and a mode was not already
   // set. Other modules can also enable the overlay directly for other uses.
-  $user_data = user_data_get('overlay', $user->uid, 'enabled');
+  $user_data = drupal_container()->get('user.data')->get('overlay', $user->uid, 'enabled');
   $use_overlay = !isset($user_data) || $user_data;
   if (empty($mode) && user_access('access overlay') && $use_overlay) {
     $current_path = current_path();
@@ -356,7 +356,7 @@ function overlay_user_dismiss_message() {
     throw new AccessDeniedHttpException();
   }
 
-  user_data_set('overlay', $user->uid, 'message_dismissed', 1);
+  drupal_container()->get('user.data')->set('overlay', $user->uid, 'message_dismissed', 1);
   drupal_set_message(t('The message has been dismissed. You can change your overlay settings at any time by visiting your profile page.'));
   // Destination is normally given. Go to the user profile as a fallback.
   drupal_goto('user/' . $user->uid . '/edit');
@@ -383,7 +383,7 @@ function overlay_disable_message() {
     return $build;
   }
 
-  $user_data = user_data_get('overlay', $user->uid);
+  $user_data = drupal_container()->get('user.data')->get('overlay', $user->uid);
   if (empty($user_data['message_dismissed']) && (!isset($user_data['enabled']) || $user_data['enabled'])) {
     $build = array(
       '#theme' => 'overlay_disable_message',
diff --git a/core/modules/user/lib/Drupal/user/UserBundle.php b/core/modules/user/lib/Drupal/user/UserBundle.php
new file mode 100644
index 0000000..4e356b2
--- /dev/null
+++ b/core/modules/user/lib/Drupal/user/UserBundle.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\user\UserBundle.
+ */
+
+namespace Drupal\user;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\HttpKernel\Bundle\Bundle;
+
+/**
+ * User dependency injection container.
+ */
+class UserBundle extends Bundle {
+
+  /**
+   * Overrides Symfony\Component\HttpKernel\Bundle\Bundle::build().
+   */
+  public function build(ContainerBuilder $container) {
+    $container
+      ->register('user.data', 'Drupal\user\UserData')
+      ->addArgument('database');
+  }
+
+}
diff --git a/core/modules/user/lib/Drupal/user/UserData.php b/core/modules/user/lib/Drupal/user/UserData.php
new file mode 100644
index 0000000..13855d2
--- /dev/null
+++ b/core/modules/user/lib/Drupal/user/UserData.php
@@ -0,0 +1,164 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\user\UserData.
+ */
+
+namespace Drupal\user;
+
+use Drupal\Core\Database\Connection;
+
+/**
+ * Defines the user data service.
+ */
+class UserData {
+
+  /**
+   * The database connection to use.
+   *
+   * @var \Drupal\Core\Database\Connection
+   */
+  protected $connection;
+
+  /**
+   * Constructs a new user data service.
+   *
+   * @param \Drupal\Core\Database\Connection $connection
+   *   The database connection to use.
+   */
+  public function __construct(Connection $connection) {
+    $this->connection = $connection;
+  }
+
+  /**
+   * Returns data stored for a user account.
+   *
+   * @param string $module
+   *   The name of the module the data is associated with.
+   * @param integer $uid
+   *   (optional) The user account ID the data is associated with.
+   * @param string $name
+   *   (optional) The name of the data key.
+   *
+   * @return mixed|array
+   *   The requested user account data, depending on the arguments passed:
+   *   - For $module, $name, and $uid, the stored data is returned, or NULL if
+   *     no data was found.
+   *   - For $module and $uid, an associative array is returned that contains
+   *     the stored data name/value pairs.
+   *   - For $module and $name, an associative array is returned whose keys are
+   *     user IDs and whose values contain the stored data.
+   *   - For $module only, an associative array is returned that contains all
+   *     existing data for $module in all user accounts, keyed first by user ID
+   *     and $name second.
+   */
+  public function get($module, $uid = NULL, $name = NULL) {
+    $query = $this->connection->select('users_data', 'ud')
+      ->fields('ud')
+      ->condition('module', $module);
+    if (isset($uid)) {
+      $query->condition('uid', $uid);
+    }
+    if (isset($name)) {
+      $query->condition('name', $name);
+    }
+    $result = $query->execute();
+    // If $module, $uid, and $name was passed, return the value.
+    if (isset($name) && isset($uid)) {
+      $result = $result->fetchAllAssoc('uid');
+      if (isset($result[$uid])) {
+        return $result[$uid]->serialized ? unserialize($result[$uid]->value) : $result[$uid]->value;
+      }
+      return NULL;
+    }
+    // If $module and $uid was passed, return the name/value pairs.
+    elseif (isset($uid)) {
+      $return = array();
+      foreach ($result as $record) {
+        $return[$record->name] = ($record->serialized ? unserialize($record->value) : $record->value);
+      }
+      return $return;
+    }
+    // If $module and $name was passed, return the uid/value pairs.
+    elseif (isset($name)) {
+      $return = array();
+      foreach ($result as $record) {
+        $return[$record->uid] = ($record->serialized ? unserialize($record->value) : $record->value);
+      }
+      return $return;
+    }
+    // If only $module was passed, return data keyed by uid and name.
+    else {
+      $return = array();
+      foreach ($result as $record) {
+        $return[$record->uid][$record->name] = ($record->serialized ? unserialize($record->value) : $record->value);
+      }
+      return $return;
+    }
+  }
+
+  /**
+   * Stores data for a user account.
+   *
+   * @param string $module
+   *   The name of the module the data is associated with.
+   * @param integer $uid
+   *   The user account ID the data is associated with.
+   * @param string $name
+   *   The name of the data key.
+   * @param mixed $value
+   *   The value to store. Non-scalar values are serialized automatically.
+   *
+   * @return void
+   */
+  public function set($module, $uid, $name, $value) {
+    $serialized = 0;
+    if (!is_scalar($value)) {
+      $value = serialize($value);
+      $serialized = 1;
+    }
+    $this->connection->merge('users_data')
+      ->key(array(
+        'uid' => $uid,
+        'module' => $module,
+        'name' => $name,
+      ))
+      ->fields(array(
+        'value' => $value,
+        'serialized' => $serialized,
+      ))
+      ->execute();
+  }
+
+  /**
+   * Deletes data stored for a user account.
+   *
+   * @param string|array $module
+   *   (optional) The name of the module the data is associated with. Can also
+   *   be an array to delete the data of multiple modules.
+   * @param integer|array $uid
+   *   (optional) The user account ID the data is associated with. If omitted,
+   *   all data for $module is deleted. Can also be an array of IDs to delete
+   *   the data of multiple user accounts.
+   * @param string $name
+   *   (optional) The name of the data key. If omitted, all data associated with
+   *   $module and $uid is deleted.
+   *
+   * @return void
+   */
+  public function delete($module = NULL, $uid = NULL, $name = NULL) {
+    $query = $this->connection->delete('users_data');
+    if (isset($module)) {
+      $query->condition('module', $module);
+    }
+    if (isset($uid)) {
+      $query->condition('uid', $uid);
+    }
+    if (isset($name)) {
+      $query->condition('name', $name);
+    }
+    $query->execute();
+  }
+
+}
diff --git a/core/modules/user/lib/Drupal/user/UserStorageController.php b/core/modules/user/lib/Drupal/user/UserStorageController.php
index 2c92aac..ced445e 100644
--- a/core/modules/user/lib/Drupal/user/UserStorageController.php
+++ b/core/modules/user/lib/Drupal/user/UserStorageController.php
@@ -151,7 +151,7 @@ protected function preSave(EntityInterface $entity) {
     // Store account cancellation information.
     foreach (array('user_cancel_method', 'user_cancel_notify') as $key) {
       if (isset($entity->{$key})) {
-        user_data_set('user', $entity->id(), substr($key, 5), $entity->{$key});
+        drupal_container()->get('user.data')->set('user', $entity->id(), substr($key, 5), $entity->{$key});
       }
     }
   }
@@ -228,11 +228,9 @@ protected function postDelete($entities) {
     db_delete('users_roles')
       ->condition('uid', array_keys($entities), 'IN')
       ->execute();
-    db_delete('users_data')
-      ->condition('uid', array_keys($entities), 'IN')
-      ->execute();
     db_delete('authmap')
       ->condition('uid', array_keys($entities), 'IN')
       ->execute();
+    drupal_container()->get('user.data')->delete(NULL, array_keys($entities));
   }
 }
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 855396a..002301c 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -2998,9 +2998,7 @@ function user_modules_uninstalled($modules) {
      ->condition('module', $modules, 'IN')
      ->execute();
   // Remove any potentially orphan module data stored for users.
-  db_delete('users_data')
-    ->condition('module', $modules, 'IN')
-    ->execute();
+  drupal_container()->get('user.data')->delete($modules);
 }
 
 /**
@@ -3104,129 +3102,3 @@ function user_library_info() {
 
   return $libraries;
 }
-
-/**
- * Returns data stored for a user account.
- *
- * @param string $module
- *   The name of the module the data is associated with.
- * @param integer $uid
- *   (optional) The user account ID the data is associated with.
- * @param string $name
- *   (optional) The name of the data key.
- *
- * @return mixed|array
- *   The requested user account data, depending on the arguments passed:
- *   - For $module, $name, and $uid, the stored data is returned, or NULL if no
- *     data was found.
- *   - For $module and $uid, an associative array is returned that contains the
- *     stored data name/value pairs.
- *   - For $module and $name, an associative array is returned whose keys are
- *     user IDs and whose values contain the stored data.
- *   - For $module only, an associative array is returned that contains all
- *     existing data for $module in all user accounts, keyed by first by user ID
- *     and $name second.
- */
-function user_data_get($module, $uid = NULL, $name = NULL) {
-  $query = db_select('users_data', 'ud')
-    ->fields('ud')
-    ->condition('module', $module);
-  if (isset($uid)) {
-    $query->condition('uid', $uid);
-  }
-  if (isset($name)) {
-    $query->condition('name', $name);
-  }
-  $result = $query->execute();
-  // If $module, $uid, and $name was passed, return the value.
-  if (isset($name) && isset($uid)) {
-    $result = $result->fetchAllAssoc('uid');
-    if (isset($result[$uid])) {
-      return $result[$uid]->serialized ? unserialize($result[$uid]->value) : $result[$uid]->value;
-    }
-    return NULL;
-  }
-  // If $module and $uid was passed, return the name/value pairs.
-  elseif (isset($uid)) {
-    $return = array();
-    foreach ($result as $record) {
-      $return[$record->name] = ($record->serialized ? unserialize($record->value) : $record->value);
-    }
-    return $return;
-  }
-  // If $module and $name was passed, return the uid/value pairs.
-  elseif (isset($name)) {
-    $return = array();
-    foreach ($result as $record) {
-      $return[$record->uid] = ($record->serialized ? unserialize($record->value) : $record->value);
-    }
-    return $return;
-  }
-  // If only $module was passed, return data keyed by uid and name.
-  else {
-    $return = array();
-    foreach ($result as $record) {
-      $return[$record->uid][$record->name] = ($record->serialized ? unserialize($record->value) : $record->value);
-    }
-    return $return;
-  }
-}
-
-/**
- * Stores data for a user account.
- *
- * @param string $module
- *   The name of the module the data is associated with.
- * @param integer $uid
- *   The user account ID the data is associated with.
- * @param string $name
- *   The name of the data key.
- * @param mixed $value
- *   The value to store. Non-scalar values are serialized automatically.
- *
- * @return void
- */
-function user_data_set($module, $uid, $name, $value) {
-  $serialized = 0;
-  if (!is_scalar($value)) {
-    $value = serialize($value);
-    $serialized = 1;
-  }
-  db_merge('users_data')
-    ->key(array(
-      'uid' => $uid,
-      'module' => $module,
-      'name' => $name,
-    ))
-    ->fields(array(
-      'value' => $value,
-      'serialized' => $serialized,
-    ))
-    ->execute();
-}
-
-/**
- * Deletes data stored for a user account.
- *
- * @param string $module
- *   The name of the module the data is associated with.
- * @param integer $uid
- *   (optional) The user account ID the data is associated with. If omitted, all
- *   data for $module is deleted.
- * @param string $name
- *   (optional) The name of the data key. If omitted, all data associated with
- *   $module and $uid is deleted.
- *
- * @return void
- */
-function user_data_del($module, $uid = NULL, $name = NULL) {
-  $query = db_delete('users_data')
-    ->condition('module', $module);
-  if (isset($uid)) {
-    $query->condition('uid', $uid);
-  }
-  if (isset($name)) {
-    $query->condition('name', $name);
-  }
-  $query->execute();
-}
diff --git a/core/modules/user/user.pages.inc b/core/modules/user/user.pages.inc
index 1189f06..d45112d 100644
--- a/core/modules/user/user.pages.inc
+++ b/core/modules/user/user.pages.inc
@@ -388,7 +388,7 @@ function user_cancel_confirm($account, $timestamp = 0, $hashed_pass = '') {
   $current = REQUEST_TIME;
 
   // Basic validation of arguments.
-  $account_data = user_data_get('user', $account->id());
+  $account_data = drupal_container()->get('user.data')->get('user', $account->id());
   if (isset($account_data['cancel_method']) && !empty($timestamp) && !empty($hashed_pass)) {
     // Validate expiration and hashed password/login.
     if ($timestamp <= $current && $current - $timestamp < $timeout && $account->uid && $timestamp >= $account->login && $hashed_pass == user_pass_rehash($account->pass, $timestamp, $account->login)) {