Properly end iterating over the file once the target has been reached

Signed-off-by: Julius Härtl <jus@bitgrid.net>

Author: juliusknorr

lib/private/Files/View.php

@@ -456,11 +456,12 @@ public function readfilePart($path, $from, $to) {
 				// forward file handle via chunked fread because fseek seem to have failed
 
 				$end = $from + 1;
-				while (!feof($handle) && ftell($handle) < $end) {
+				while (!feof($handle) && ftell($handle) < $end && ftell($handle) !== $from) {
 					$len = $from - ftell($handle);
 					if ($len > $chunkSize) {
 						$len = $chunkSize;
 					}
+
 					$result = fread($handle, $len);
 
 					if ($result === false) {