Merge pull request #1100 from jsmeix/Skip_remount_async_when_systemd_…

…is_used_issue1097

Skip remount async when systemd is used.
Remounting with async option is not needed
when systemd is used because when systemd
is used remounting with sync option is skipped and
to aviod needless operations remounting with async
option is also skipped, see
#1097
and
#1099

usr/share/rear/restore/default/050_remount_async.sh

@@ -5,10 +5,19 @@
 # via finalize/default/900_remount_sync.sh
 # see also https://github.com/rear/rear/issues/1097
 #
+# Remounting with async option is not needed when systemd is used because
+# when systemd is used remounting with sync option is skipped in a preceding
+# recover WORKFLOW via finalize/default/900_remount_sync.sh and to aviod
+# needless operations remounting with async option is also skipped here
+# cf. https://github.com/rear/rear/issues/1097
 
 # Skip if not restoreonly WORKFLOW:
 test "restoreonly" = "$WORKFLOW" || return 0
 
+# Skip if systemd is used
+# systemctl gets copied into the recovery system as /bin/systemctl:
+test -x /bin/systemctl && return 0
+
 while read mountpoint device mountby filesystem junk ; do
     if ! mount -o remount,async "${device}" $TARGET_FS_ROOT"$mountpoint" ; then
         LogPrint "Remount async of '${device}' failed which can result very slow restore"