fix: use mountpoint from storage to find the encryption keys

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/Files/Storage/Wrapper/Encryption.php

@@ -44,6 +44,7 @@
 use OC\Files\Filesystem;
 use OC\Files\Mount\Manager;
 use OC\Files\ObjectStore\ObjectStoreStorage;
+use OC\Files\Storage\Common;
 use OC\Files\Storage\LocalTempFileTrait;
 use OC\Memcache\ArrayCache;
 use OCP\Cache\CappedMemoryCache;
@@ -806,9 +807,8 @@ private function copyBetweenStorage(
 
 		// first copy the keys that we reuse the existing file key on the target location
 		// and don't create a new one which would break versions for example.
-		$mount = $this->mountManager->findByStorageId($sourceStorage->getId());
-		if (count($mount) >= 1) {
-			$mountPoint = $mount[0]->getMountPoint();
+		if ($sourceStorage->instanceOfStorage(Common::class) && $sourceStorage->getMountOption('mount_point')) {
+			$mountPoint = $sourceStorage->getMountOption('mount_point');
 			$source = $mountPoint . '/' . $sourceInternalPath;
 			$target = $this->getFullPath($targetInternalPath);
 			$this->copyKeys($source, $target);