diff --git a/lib/private/files/objectstore/objectstorestorage.php b/lib/private/files/objectstore/objectstorestorage.php
index 4bc258a5807..09114d26de9 100644
--- a/lib/private/files/objectstore/objectstorestorage.php
+++ b/lib/private/files/objectstore/objectstorestorage.php
@@ -407,11 +407,11 @@ class ObjectStoreStorage extends \OC\Files\Storage\Common {
 	}
 
 	/**
-	 * external changes are not supported
+	 * external changes are not supported, exclusive access to the object storage is assumed
 	 *
 	 * @param string $path
 	 * @param int $time
-	 * @return bool
+	 * @return false
 	 */
 	public function hasUpdated($path, $time) {
 		return false;
diff --git a/lib/private/files/storage/common.php b/lib/private/files/storage/common.php
index ecc75298b66..9657b511f15 100644
--- a/lib/private/files/storage/common.php
+++ b/lib/private/files/storage/common.php
@@ -279,6 +279,11 @@ abstract class Common implements \OC\Files\Storage\Storage {
 	/**
 	 * check if a file or folder has been updated since $time
 	 *
+	 * The method is only used to check if the cache needs to be updated. Storage backends that don't support checking
+	 * the mtime should always return false here. As a result storage implementations that always return false expect
+	 * exclusive access to the backend and will not pick up files that have been added in a way that circumvents
+	 * ownClouds filesystem.
+	 *
 	 * @param string $path
 	 * @param int $time
 	 * @return bool
diff --git a/tests/lib/files/objectstore/swift.php b/tests/lib/files/objectstore/swift.php
index 8ac899288e6..7f3b45c0dab 100644
--- a/tests/lib/files/objectstore/swift.php
+++ b/tests/lib/files/objectstore/swift.php
@@ -77,7 +77,30 @@ class Swift extends \Test\Files\Storage\Storage {
 		}
 		$this->objectStorage->deleteContainer(true);
 		$this->instance->getCache()->clear();
-		//TODO how do I clear hooks?
+	}
+
+	public function testStat() {
+		$textFile = \OC::$SERVERROOT . '/tests/data/lorem.txt';
+		$ctimeStart = time();
+		$this->instance->file_put_contents('/lorem.txt', file_get_contents($textFile));
+		$this->assertTrue($this->instance->isReadable('/lorem.txt'));
+		$ctimeEnd = time();
+		$mTime = $this->instance->filemtime('/lorem.txt');
+
+		// check that ($ctimeStart - 5) <= $mTime <= ($ctimeEnd + 1)
+		$this->assertGreaterThanOrEqual(($ctimeStart - 5), $mTime);
+		$this->assertLessThanOrEqual(($ctimeEnd + 1), $mTime);
+		$this->assertEquals(filesize($textFile), $this->instance->filesize('/lorem.txt'));
+
+		$stat = $this->instance->stat('/lorem.txt');
+		//only size and mtime are required in the result
+		$this->assertEquals($stat['size'], $this->instance->filesize('/lorem.txt'));
+		$this->assertEquals($stat['mtime'], $mTime);
+
+		if ($this->instance->touch('/lorem.txt', 100) !== false) {
+			$mTime = $this->instance->filemtime('/lorem.txt');
+			$this->assertEquals($mTime, 100);
+		}
 	}
 
 }