sh-3.2# systemctl status persist.mount
persist.mount - Droid mount for /persist
   Loaded: loaded (/lib/systemd/system/persist.mount; enabled)
   Active: inactive (dead)
    Where: /persist
     What: /dev/block/platform/msm_sdcc.1/by-name/persist

sh-3.2# systemctl status system.mount
system.mount - Droid mount for /system
   Loaded: loaded (/lib/systemd/system/system.mount; enabled)
   Active: inactive (dead)
    Where: /system
     What: /dev/block/platform/msm_sdcc.1/by-name/system

sh-3.2# systemctl status local-fs-pre.target
local-fs-pre.target - Local File Systems (Pre)
   Loaded: loaded (/lib/systemd/system/local-fs-pre.target; static)
   Active: active since Wed 2015-03-11 12:28:30 CET; 44s ago
     Docs: man:systemd.special(7)

sh-3.2# systemctl status local-fs.target
local-fs.target - Local File Systems
   Loaded: loaded (/lib/systemd/system/local-fs.target; static)
   Active: active since Wed 2015-03-11 12:28:59 CET; 19s ago
     Docs: man:systemd.special(7)

sh-3.2# cat /etc/systemd/system/local-fs.target.wants/system.mount
[Unit]
Description=Droid mount for /system
Before=local-fs.target
After=local-fs-pre.target

[Mount]
What=/dev/block/platform/msm_sdcc.1/by-name/system
Where=/system
Type=ext4
#Options=ro,barrier=1
# Options had SELinux context option:

# Default is 90 which makes mount period too long in case of
# errors so drop it down a notch.
TimeoutSec=10

[Install]
WantedBy=local-fs.target

# From ./out/target/product/flo/root/fstab.flo :
# /dev/block/platform/msm_sdcc.1/by-name/system       /system         ext4    ro,barrier=1                                                                 wait