core/includes/file.inc                             |   95 ++++++++------------
 core/lib/Drupal/Core/StreamWrapper/LocalStream.php |    4 +-
 .../lib/Drupal/system/Tests/File/DirectoryTest.php |   11 +--
 3 files changed, 41 insertions(+), 69 deletions(-)

diff --git a/core/includes/file.inc b/core/includes/file.inc
index 131fe58..a56d3bd 100644
--- a/core/includes/file.inc
+++ b/core/includes/file.inc
@@ -1709,22 +1709,19 @@ function drupal_basename($uri, $suffix = NULL) {
 }
 
 /**
- * Creates a directory using Drupal's default mode.
+ * Creates a directory.
  *
- * PHP's mkdir() does not respect Drupal's default permissions mode. If a mode
- * is not provided, this function will make sure that Drupal's is used.
- *
- * Compatibility: normal paths and stream wrappers.
+ * PHP's mkdir() does not default to the Drupal directory mode and only sets the
+ * mode on the top-level directory when creating recursively.
  *
  * @param $uri
  *   A URI or pathname.
  * @param $mode
- *   By default the Drupal mode is used. Note that you probably want to
- *   specify the mode as an octal number, which means it should have a
- *   leading zero. Also note that Drupal does NOT obey umask().
+ *   Mode given to created directories. By default the Drupal mode is used. It
+ *   must have a leading zero.
  * @param $recursive
- *   Create directories recursively, defaults to FALSE. Note: recursive mkdir
- *   does not work with a $mode which denies writing to the owner.
+ *   Create directories recursively, defaults to FALSE. Cannot work with a $mode
+ *   which denies writing or execution to the owner of the process.
  * @param $context
  *   Refer to http://php.net/manual/ref.stream.php
  *
@@ -1739,13 +1736,39 @@ function drupal_mkdir($uri, $mode = NULL, $recursive = FALSE, $context = NULL) {
   if (!isset($mode)) {
     $mode = variable_get('file_chmod_directory', 0775);
   }
-  return file_uri_scheme($uri) ? _drupal_mkdir_call($uri, $mode, $recursive, $context) : _drupal_mkdir_local($uri, $mode, $recursive, $context);
+
+  // If recursive and there is no URI scheme, create each missing component of
+  // the parent directory individually so they are created with the correct
+  // mode. Schemes can handle this issue in their own implementation.
+  if ($recursive && !file_uri_scheme($uri)) {
+    $components = explode(DIRECTORY_SEPARATOR, $uri);
+    array_pop($components);
+    $recursive_path = '';
+    foreach ($components as $component) {
+      $recursive_path .= $component;
+
+      if (!file_exists($recursive_path)) {
+        if (!_drupal_mkdir_call($recursive_path, $mode, FALSE, $context)) {
+          return FALSE;
+        }
+      }
+
+      $recursive_path .= DIRECTORY_SEPARATOR;
+    }
+
+    // The top-level directory must not exist yet as it needs to be created with
+    // the correct mode, so fall through to the final call.
+    $recursive = FALSE;
+  }
+
+  return _drupal_mkdir_call($uri, $mode, $recursive, $context);
 }
 
 /**
- * Ensures we don't pass a NULL as a context resource to mkdir().
+ * Helper function. Ensures we don't pass a NULL as a context resource to
+ * mkdir().
  *
- * {@inheritdoc}
+ * @see drupal_mkdir()
  */
 function _drupal_mkdir_call($uri, $mode, $recursive, $context) {
   if (isset($context)) {
@@ -1757,52 +1780,6 @@ function _drupal_mkdir_call($uri, $mode, $recursive, $context) {
 }
 
 /**
- * Creates one or more directories from a local path.
- *
- * @param string $localpath
- *   A local pathname.
- * @param integer $mode
- *   The mode will be passed only to new directories in the path. Defaults to
- *   Drupal mode.
- * @param boolean $recursive
- *   Whether or not directories should be created recursively.
- * @param resource $context
- *   Refer to http://php.net/manual/ref.stream.php
- *
- * @return boolean
- *   TRUE on success, or FALSE on failure.
- */
-function _drupal_mkdir_local($localpath, $mode = NULL, $recursive = FALSE, $context = NULL) {
-  $mode = isset($mode) ? $mode : variable_get('file_chmod_directory', 0775);
-
-  if ($recursive) {
-    $directories = explode(DIRECTORY_SEPARATOR, $localpath);
-    $directory_path = '';
-    foreach ($directories as $directory) {
-      $directory_path = $directory_path ? $directory_path . DIRECTORY_SEPARATOR . $directory : $directory;
-      if (!file_exists($directory_path)) {
-        if (!_drupal_mkdir_call($directory_path, $mode, FALSE, $context)) {
-          return FALSE;
-        }
-        // We can't rely on mkdir() setting the mode recursively because mkdir
-        // (correctly) obeys umask() but we can't run umask() because it is set
-        // on a process level:
-        // @see http://php.net/manual/en/function.umask.php#105150
-        // Therefore, sadly, we need to chmod after the dirs are created.
-        if (!chmod($directory_path, $mode)) {
-          return FALSE;
-        }
-      }
-    }
-    return TRUE;
-  }
-  else {
-    // If this is not recursive, PHP's mkdir() needs no adjustment.
-    return _drupal_mkdir_call($localpath, $mode, $recursive, $context);
-  }
-}
-
-/**
  * Removes a directory.
  *
  * PHP's rmdir() is broken on Windows, as it can fail to remove a directory
diff --git a/core/lib/Drupal/Core/StreamWrapper/LocalStream.php b/core/lib/Drupal/Core/StreamWrapper/LocalStream.php
index 570175e..f84ecb1 100644
--- a/core/lib/Drupal/Core/StreamWrapper/LocalStream.php
+++ b/core/lib/Drupal/Core/StreamWrapper/LocalStream.php
@@ -425,10 +425,10 @@ abstract class LocalStream implements StreamWrapperInterface {
       $localpath = $this->getLocalPath($uri);
     }
     if ($options & STREAM_REPORT_ERRORS) {
-      return _drupal_mkdir_local($localpath, $mode, $recursive);
+      return drupal_mkdir($localpath, $mode, $recursive);
     }
     else {
-      return @_drupal_mkdir_local($localpath, $mode, $recursive);
+      return @drupal_mkdir($localpath, $mode, $recursive);
     }
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/File/DirectoryTest.php b/core/modules/system/lib/Drupal/system/Tests/File/DirectoryTest.php
index d25e823..e2b0f39 100644
--- a/core/modules/system/lib/Drupal/system/Tests/File/DirectoryTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/File/DirectoryTest.php
@@ -32,24 +32,19 @@ class DirectoryTest extends FileTestBase {
 
     // Files directory already exists.
     $this->assertTrue(is_dir($directory), t('Files directory already exists.'), 'File');
-    // Make files directory writable only.
-    $old_mode = fileperms($directory);
 
     // Create the directories.
     $parent_path = $directory . DIRECTORY_SEPARATOR . $parent;
     $child_path = $parent_path . DIRECTORY_SEPARATOR . $child;
-    $this->assertTrue(drupal_mkdir($child_path, 0444), t('No error reported when creating new local directories.'), 'File');
+    $this->assertTrue(drupal_mkdir($child_path, 0755, TRUE), t('No error reported when creating new local directories.'), 'File');
 
     // Ensure new directories also exist.
     $this->assertTrue(is_dir($parent_path), t('New parent directory actually exists.'), 'File');
     $this->assertTrue(is_dir($child_path), t('New child directory actually exists.'), 'File');
 
     // Check that new directory permissions were set properly.
-    $this->assertDirectoryPermissions($parent_path, 0444);
-    $this->assertDirectoryPermissions($child_path, 0444);
-
-    // Check that existing directory permissions were not modified.
-    $this->assertDirectoryPermissions($directory, $old_mode);
+    $this->assertDirectoryPermissions($parent_path, 0755);
+    $this->assertDirectoryPermissions($child_path, 0755);
   }
 
   /**