More XFS madness fixes

secondary.py

@@ -122,6 +122,9 @@ class Backup:
             stat = os.statvfs(self.dst_root)
             free = stat.f_frsize * stat.f_bavail
             need = size + stat.f_frsize
+            if stat.f_bavail == stat.f_bfree:
+                # Probably on xfs, make sure we alway have 1 MB extra
+                need += 1024*1024
             if path:
                 need += stat.f_frsize * len(path.split('/'))
             return (free, need)