normalize the path once in upload.php is enough - THX Robin for this hint

apps/files/ajax/upload.php

@@ -48,15 +48,11 @@ if(strpos($dir, '..') === false) {
 	$fileCount=count($files['name']);
 	for($i=0;$i<$fileCount;$i++) {
         $target = OCP\Files::buildNotExistingFileName(stripslashes($dir), $files['name'][$i]);
+		// $path needs to be normalized - this failed within drag'n'drop upload to a sub-folder
+		$target = OC_Filesystem::normalizePath($target);
 		if(is_uploaded_file($files['tmp_name'][$i]) and OC_Filesystem::fromTmpFile($files['tmp_name'][$i], $target)) {
 			$meta = OC_FileCache::get($target);
 			$id = OC_FileCache::getId($target);
-			// in case the upload goes to a sub directory getID() returns -1 and $target needs to be normalized
-			// calling normalizePath() inside getId() causes endless scan.
-			if ($id == -1) {
-				$path = OC_Filesystem::normalizePath($target);
-				$id = OC_FileCache::getId($path);
-			}
 			$result[]=array( "status" => "success", 'mime'=>$meta['mimetype'], 'size'=>$meta['size'], 'id'=>$id, 'name'=>basename($target));
 		}
 	}

lib/filecache.php

@@ -43,8 +43,6 @@ class OC_FileCache{
 	 * - versioned
 	 */
 	public static function get($path, $root=false) {
-		// $path needs to be normalized - this failed within drag'n'drop upload to a subfolder
-		$path = OC_Filesystem::normalizePath($path);
 		if(OC_FileCache_Update::hasUpdated($path, $root)) {
 			if($root===false) {//filesystem hooks are only valid for the default root
 				OC_Hook::emit('OC_Filesystem', 'post_write', array('path'=>$path));