Add error handling to the file cache upgrade

lib/files/cache/upgrade.php

@@ -39,11 +39,12 @@ class Upgrade {
 
 		if ($row = $this->legacy->get($path)) {
 			$data = $this->getNewData($row);
+			if ($data) {
 				$this->insert($data);
-
 				$this->upgradeChilds($data['id'], $mode);
 			}
 		}
+	}
 
 	/**
 	 * @param int $id
@@ -53,12 +54,14 @@ class Upgrade {
 		foreach ($children as $child) {
 			$childData = $this->getNewData($child);
 			\OC_Hook::emit('\OC\Files\Cache\Upgrade', 'migrate_path', $child['path']);
+			if ($childData) {
 				$this->insert($childData);
 				if ($mode == Scanner::SCAN_RECURSIVE) {
 					$this->upgradeChilds($child['id']);
 				}
 			}
 		}
+	}
 
 	/**
 	 * @param array $data the data for the new cache
@@ -95,11 +98,12 @@ class Upgrade {
 	 */
 	function getNewData($data) {
 		$newData = $data;
-		list($storage, $internalPath) = \OC\Files\Filesystem::resolvePath($data['path']);
 		/**
 		 * @var \OC\Files\Storage\Storage $storage
 		 * @var string $internalPath;
 		 */
+		list($storage, $internalPath) = \OC\Files\Filesystem::resolvePath($data['path']);
+		if ($storage) {
 			$newData['path_hash'] = md5($internalPath);
 			$newData['path'] = $internalPath;
 			$newData['storage'] = $this->getNumericId($storage);
@@ -109,6 +113,10 @@ class Upgrade {
 			$newData['mimetype'] = $this->getMimetypeId($newData['mimetype'], $storage);
 			$newData['mimepart'] = $this->getMimetypeId($newData['mimepart'], $storage);
 			return $newData;
+		} else {
+			\OC_Log::write('core', 'Unable to migrate data from old cache for '.$data['path'].' because the storage was not found', \OC_Log::ERROR);
+			return false;
+		}
 	}
 
 	/**