From 6568d624cc402a4f412efa84398447614c9eaf35 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Wed, 30 Aug 2017 15:51:44 +0200
Subject: [PATCH] backup/restore: make backup header extraction faster

Abort tar process after extracting requested files - do not parse the
archive until the end (possibly tens of GB later).

Fixes QubesOS/qubes-issues#2986
---
 qubesadmin/backup/restore.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/qubesadmin/backup/restore.py b/qubesadmin/backup/restore.py
index 981282a..0df5df1 100644
--- a/qubesadmin/backup/restore.py
+++ b/qubesadmin/backup/restore.py
@@ -869,6 +869,7 @@ class BackupRestore(object):
 
             tar1_command = ['tar',
                             '-ixv',
+                            '--occurrence=1',
                             '-C', self.tmpdir] + filelist
 
         tar1_env = os.environ.copy()