mountfs: support /etc/mtab as a symlink to /proc/mounts for smooth systemd transition

etc/rc.d/init.d/mountfs

@@ -18,15 +18,12 @@ case "$1" in
       # Dump dmesg to log file
       dmesg > /var/log/dmesg.log
 
-      # Clean and recreate /etc/mtab
-      rm -f /etc/mtab # delete in case of symlink
-      cat /proc/mounts | \
-         grep -v "^rootfs" | \
-         grep -v "^/dev/cloop" | \
-         grep -v "^devfs" | \
-         grep -v "^sysfs" | \
-         grep -v "^/dev/root.old" >/etc/mtab
+      # Check that mtab is a symlink to /proc/mounts
+      [ -L /etc/mtab ] || {
+         rm -f /etc/mtab # delete if not a symlink
          rm -f /etc/mtab~ /etc/mtab~~
+         ln -s /proc/mounts /etc/mtab
+      }
 
       $PLYMOUTH --sysinit
 
@@ -45,9 +42,6 @@ case "$1" in
    ;;
    stop)
       echo -n "Unmounting all other currently mounted file systems: "
-      # remove data= in /etc/mtab to prevent problems when system reboots with different mode
-      # (as with kernel 2.6.30 upgrade)
-      sed -i "s|[,]*data=[a-z]*||" /etc/mtab
 #      [ -f /proc/bus/usb/devices ] && umount /proc/bus/usb >/dev/null 2>&1
 #      umount -l /proc
 #      umount -l /sys