8.1.0 Beta - SystemD unmounts fail due to -c parameter not existing

PrimusNZ · August 17, 2017 at 2:25 PM

Copying nfs.mount.sample in the ~/.config/system.d/ and configuring yeilds a successful mount of my NAS server's files on my LibreELEC system via NFS.

Unmounts fail however due to there being no -c option in umount. This causes the system to hang on shutdown (Which is annoying when you're trying to save a buck by shutting down an idle system)

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● storage-test.mount - test nfs mount script

Loaded: loaded (/storage/.config/system.d/storage-test.mount; disabled; vendor preset: disabled)

Active: active (mounted) (Result: exit-code) since Fri 2017-08-18 01:21:39 NZST; 1s ago

Where: /storage/test

What: 192.168.254.254:/mnt/user/ISOS

Process: 3056 ExecUnmount=/usr/bin/umount /storage/test -c (code=exited, status=1/FAILURE)

Process: 3034 ExecMount=/usr/bin/mount 192.168.254.254:/mnt/user/ISOS /storage/test -t nfs (code=exited, status=0/SUCCESS)

CGroup: /system.slice/storage-test.mount

Aug 18 01:21:30 RyanHTPC systemd[1]: Mounting test nfs mount script...

Aug 18 01:21:30 RyanHTPC systemd[1]: Mounted test nfs mount script.

Aug 18 01:21:39 RyanHTPC systemd[1]: Unmounting test nfs mount script...

Aug 18 01:21:39 RyanHTPC systemd[1]: storage-test.mount: Mount process exited, code=exited status=1

Aug 18 01:21:39 RyanHTPC systemd[1]: Failed unmounting test nfs mount script.

umount command:

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RyanHTPC:~/.config/system.d # umount /storage/test -c

umount: invalid option -- 'c'

BusyBox v1.26.2 (2017-07-28 19:38:17 CEST) multi-call binary.

Usage: umount [OPTIONS] FILESYSTEM|DIRECTORY

Unmount file systems

-a Unmount all file systems

-r Try to remount devices as read-only if mount is busy

-l Lazy umount (detach filesystem)

-f Force umount (i.e., unreachable NFS server)

-D Don't free loop device even if it has been use

It seems that either systemd needs to be patched to not use -c or the version of umount in LibreELEC needs to be updated to a version with the -c flag (Or have this option enabled)

This also seems to occur with CIFS mounts, however I cannot confirm if its the same -c option causing the unmount issue.

**milhouse** · August 17, 2017 at 11:06 PM

Can you post your nfs service:

Code

cat /storage/.config/system.d/storage-test.mount | pastebinit

I've tested an NFS mount based on the default nfs.mount.sample (pastebin) but can't see a problem:

Code

rpi22:~ # systemctl status storage-movies2.mount
* storage-movies2.mount - test nfs mount script
   Loaded: loaded (/storage/.config/system.d/storage-movies2.mount; enabled; vendor preset: disabled)
   Active: active (mounted) since Thu 2017-08-17 19:54:29 UTC; 45s ago
    Where: /storage/movies2
     What: 192.168.0.3:/mnt/share
  Process: 675 ExecMount=/usr/bin/mount 192.168.0.3:/mnt/share /storage/movies2 -t nfs (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/storage-movies2.mount

Aug 17 19:54:29 rpi22 systemd[1]: Mounting test nfs mount script...
Aug 17 19:54:29 rpi22 systemd[1]: Mounted test nfs mount script.
rpi22:~ # systemctl stop storage-movies2.mount
rpi22:~ # systemctl status storage-movies2.mount
* storage-movies2.mount - test nfs mount script
   Loaded: loaded (/storage/.config/system.d/storage-movies2.mount; enabled; vendor preset: disabled)
   Active: inactive (dead) since Thu 2017-08-17 19:55:22 UTC; 2s ago
    Where: /storage/movies2
     What: 192.168.0.3:/mnt/share
  Process: 821 ExecUnmount=/usr/bin/umount /storage/movies2 (code=exited, status=0/SUCCESS)
  Process: 675 ExecMount=/usr/bin/mount 192.168.0.3:/mnt/share /storage/movies2 -t nfs (code=exited, status=0/SUCCESS)

Aug 17 19:54:29 rpi22 systemd[1]: Mounting test nfs mount script...
Aug 17 19:54:29 rpi22 systemd[1]: Mounted test nfs mount script.
Aug 17 19:55:22 rpi22 systemd[1]: Unmounting test nfs mount script...
Aug 17 19:55:22 rpi22 systemd[1]: Unmounted test nfs mount script.

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I've tested this with 8.0.2, 8.1.0 and also LE9.

Looking at the systemd source code there's no evidence it adds the "-c" argument when unmounting:
systemd/mount.c at v232 · systemd/systemd · GitHub

PrimusNZ · August 18, 2017 at 12:03 AM

Heres my mount file XVRQ

Code

LoungeHTPC:~ # systemctl start storage-test.mount
LoungeHTPC:~ # systemctl stop storage-test.mount
Job for storage-test.mount failed.
See "systemctl  status storage-test.mount" and "journalctl  -xe" for details.

LoungeHTPC:~ # systemctl status storage-test.mount
● storage-test.mount - test nfs mount script
   Loaded: loaded (/storage/.config/system.d/storage-test.mount; disabled; vendor preset: disabled)
   Active: active (mounted) (Result: exit-code) since Fri 2017-08-18 10:59:45 NZST; 1min 47s ago
    Where: /storage/test
     What: 192.168.254.254:/mnt/user/ISOS
  Process: 7172 ExecUnmount=/usr/bin/umount /storage/test -c (code=exited, status=1/FAILURE)
  Process: 7163 ExecMount=/usr/bin/mount 192.168.254.254:/mnt/user/ISOS /storage/test -t nfs (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/storage-test.mount

Aug 18 10:59:41 LoungeHTPC systemd[1]: Mounting test nfs mount script...
Aug 18 10:59:41 LoungeHTPC systemd[1]: Mounted test nfs mount script.
Aug 18 10:59:45 LoungeHTPC systemd[1]: Unmounting test nfs mount script...
Aug 18 10:59:45 LoungeHTPC systemd[1]: storage-test.mount: Mount process exited, code=exited status=1
Aug 18 10:59:45 LoungeHTPC systemd[1]: Failed unmounting test nfs mount script.

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**milhouse** · August 18, 2017 at 12:12 AM

It's just bizarre... I don't know right now what could possibly be causing this.

PrimusNZ · August 18, 2017 at 12:26 AM

Quote from milhouse

It's just bizarre... I don't know right now what could possibly be causing this.

You and me both. For now I've had to resort to using a .service file to mount and umount my directories

**escalade** · August 18, 2017 at 10:28 AM

He's using my build, so I've probably introduced this regression somehow. Could be the util-linux bump to 2.29.2 or systemd bump to 2.34. I'll be investigating, in the meantime you could mount manually in autostart.sh and unmount in shutdown.sh.

**escalade** · August 18, 2017 at 12:06 PM

I've been testing a bit, disabling the busybox mount applet and instead adding mount from util-linux seems to do the trick (i.e. it supports the -c option). Downside is that it needs helpers for nfs/cifs. I already have nfs-utils in my build, so I added cifs-utils as well and now systemd mounts/unmounts both cifs/nfs like it should.

This is probably something LE upstream will have to deal with at some point too. Perhaps busybox could be hacked to silently ignore the -c option for example, or systemd hacked to not use it. Or even better maybe busybox should support it

**milhouse** · August 18, 2017 at 9:48 PM

Probably easiest to patch it out of systemd once we update to v234 assuming busybox doesn't add support in a future version.

It's currently a one line change: systemd/mount.c at v234 · systemd/systemd · GitHub

**milhouse** · August 18, 2017 at 10:11 PM

escalade: I've opened a bug (enhancement) on busybox bugzilla requesting umount "-c" support:

10236 – busybox umount doesn't support -c

**escalade** · August 19, 2017 at 9:31 AM

milhouse

I "fixed" it like this: busybox: patch umount to accept/ignore -c option · escalade/LibreELEC.tv@ccc47da · GitHub

Couldn't find the part in systemd that added -c