[systemd-devel] Fwd: Handling ExecStop failure

[Ashish Sangwan]

We have a user space file system implementation.
Lets say the binary name is user_fs
Execution/Mounting is done by using "systemctl start user_fs.service"
and stop/umounting is done by using "systemctl stop user_fs.service"

The service file looks like following:

    [Service]
    KillMode=none
    Type=forking
    ExecStop=/opt/scripts/user_fs stop
    ExecStart=/opt/scripts/user_fs start
    Restart=on-failure
    RestartSec=10
    StartLimitBurst=3
    StartLimitInterval=60s
    StandardError=journal+console
    StandardOutput=journal+console


    [Install]
    WantedBy=default.target

When the mountpoint is busy, the ExecStop fails to umount which is expected.

    user_fs.service -
       Loaded: loaded (/etc/systemd/system/user_fs.service; enabled)
       Active: failed (Result: exit-code) since Mon 2016-05-23
01:56:15 EDT; 18min ago
      Process: 22360 ExecStop=/opt/scripts/user_fs stop (code=exited, status=32)
      Process: 21933 ExecStart=/opt/scripts/user_fs start
(code=exited, status=0/SUCCESS)
     Main PID: 21988

    May 23 01:56:15 perfnode105 user_fs [22360]: Running umount /mnt
    May 23 01:56:15 perfnode105 user_fs [22360]: umount: /mnt: target is busy
    May 23 01:56:15 perfnode105 user_fs[22360]: (In some cases useful
info about processes that
    May 23 01:56:15 perfnode105 user_fs[22360]: use the device is
found by lsof(8) or fuser(1).)

The first issue is, once the command mentioned in ExecStop failed due
to mountpoint busy, the user comes out of the mountpoint, making it
un-busy and again fires the systemctl stop command, however the status
of the service is not changed, it remained in failed state and the
mountpoint remains mounted.
We have to explicitly do umount and kill the process to clean it.
How can I avoid this issue so that once the mountpoint becomes
un-busy, executing systemctl stop again will complete successfully.

My second issue is, on failure of stopping/umounting, no failure
message appears on console although I have used StandardError option.

I will really appreciate any help.

Regards,
Ashish