ARM requires /etc/fstab entries due to not specifying mount points

[miguelpduarte]

Is there an existing issue for this?

• I have searched the existing issues

I have checked the wiki

• I have searched the wiki for this problem

Does this issue exist in the latest version?

• I'm using the latest release

Describe the bug?

Described in depth in NixOS/nixpkgs#370710 (comment)

Basically ARM seems to be unable to mount /dev/sr0 in my setup without an fstab entry, with the error:

Output was: mount: /dev/sr0: can't find mount source /dev/sr0 in /etc/fstab.
arm[45384]: ERROR: ProcessHandler.arm_subprocess: Error while running command: ['mount', '--source', '/dev/sr0']

Current workaround that I did, instead of the fstab-based approach (with fileSystems):

    systemd.mounts = [
      {
        what = "/dev/sr0";
        where = "/run/arm/dev/sr0";
        type = "udf,iso9660";
        options = "ro,defaults,users,utf8,iocharset=utf8,nofail,x-systemd.automount";
        wantedBy = ["arm@sr0.service"];
      }
    ];

The /etc/fstab approach also didn't seem to work as the ARM systemd units did not have permissions to mount the drive, failing with:

Output was: mount: /run/arm/dev/sr0: must be superuser to use mount.

The systemd.mounts approach seems to currently be the most sensible, as it ensures that the mount happens before the unit starts up (I think?), but it still seems to have some issues with unmounting:

umount: /run/arm/dev/sr0: must be superuser to unmount.

And after the whole rip was done, the drive still seemed to be mounted to /run/arm/dev/sr0, as running umount /run/arm/dev/sr0 as root was successful (and I could still see files in there 😅 ).

(Next I will monitor the drive itself while the transcoding is happening, as I'm not sure if it ejected the DVD itself or not because I was not in the same room while the process was ongoing)

To Reproduce

1. Connect DVD drive
2. Push disk in
3. ARM worker will spawn and fail to mount, then eject the DVD disk.

What OS are you seeing the problem on?

Other (please state in Anything else? section)

ARM Release Version or Git hash (You can find this in the arm settings page)

Latest git commit for this fork 🙂

Expected behavior?

No mounting issues.

Relevant log output

Anything else?

NixOS/nixpkgs#370710 (comment)

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