Systemd and noauto in fstab headache

[niowluka]

Hi everybody, new to the forum, fairly new to Debian, long time Linux user.

I am completely new to systemd though, and really struggling to set up some mount points. Here are some of the problematic entries in fstab:

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/dev/mapper/cryptdata-2tb	/home/niowluka/Videos	btrfs	subvol=videos,defaults,noatime,noexec,user,comment=x-gvfs-hide 0 0
/dev/mapper/cryptdata-2tb	/mnt/archive/music	btrfs	subvol=music,defaults,noatime,noexec,user,noauto,comment=x-gvfs-show,comment=x-gvfs-name=Archive\040Music 0 0
/dev/mapper/cryptdata-8tb	/mnt/archive/videos	ext4	defaults,noatime,noexec,user,noauto,comment=x-gvfs-show,comment=x-gvfs-name=Archive\040Video 0 0

UUID=68233986-c957-427a-af4e-e5208bf08e20 /mnt/debian/root	btrfs	subvolid=5,defaults,noatime,ssd,compress=lzouser,noauto,comment=x-gvfs-show,comment=x-gvfs-name=Debian\040Root 0 0

Line 1 mounts with no problem at boot OK

Line 2 doesn't mount at boot (noauto), shows up nicely in nautilus and thunar side pane (x-gvfs), but mounting from there fails with '... already mounted on ...' error. I tried adding x-systemd.automount, but that's just causing it to mount at boot, and also creating my own .automount unit (with After=local-fs.target to not mount at boot), but it fails to mount with the same error.
I can mount it with 'mount /mnt/archive/music' from CLI before I try to do it from the file manager, but if I do it after I get the same error in CLI (presumably because of generated .mount and .automount units). FAIL

Line 3 doesn't mount at boot (noauto), shows up nicely in nautilus and thunar side pane, and I can mount it from there, but it asks for password, even though user is specified. Another problem is that after unmounting it seems to close/remove the devmapper device ... Again, all works fine from CLI before I do anything in the file manager FAIL

Line 4 doesn't mount at boot (noauto), shows up nicely in nautilus and thunar side pane (x-gvfs), but mounting it fails with 'only permitted for root', i.e. why doesn't it ask for password ? FAIL

How can I set up those mount points to not mount at boot, but be easily mountable (right click - mount) from nautilus or thunar ?

[L_V]

The internal drives owner is root.
Then a user cannot mount internal drives without special privilege: this is logic.

The trick is in polkit-1 (policykit-1 package).
If you want to weaken the permission, you can by creating your own policy rule to be placed at

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/etc/polkit-1/localauthority/50-local.d/10-MyMountRules.pkla

I don't give you the exact content, because it would need some fresh test for Buster, and I don't need it.
But you can investigate this to start.

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/usr/share/polkit-1/actions/org.freedesktop.UDisks2.policy

  <action id="org.freedesktop.udisks2.filesystem-mount-system">
    <description>Mount a filesystem on a system device</description>
    <defaults>
      <allow_any>auth_admin</allow_any>
      <allow_inactive>auth_admin</allow_inactive>
      <allow_active>auth_admin_keep</allow_active>
    </defaults>

Directly editing /usr/share/polkit-1/actions/org.freedesktop.UDisks2.policy is not recommended...., but ... replacing auth_admin by yes should have some effect.

+ have a look at

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systemctl list-unit-files | grep mount

However, if you decide to mount your shared partitions at boot, for info, I use this option in fstab

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noauto,x-systemd.automount

[niowluka]

Thanks @L_V. I assume the polkit changes your propose would allow a user to mount any drive without privileges ? That's not exactly what I'm after, would rather there was a way to mount it from file manager, but with a password prompt ... Worst case I'd rather add user to fstab for this one.

It's the first 3 entries that I'm mostly interested in, though ...

However, if you decide to mount your shared partitions at boot, for info, I use this option in fstab

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noauto,x-systemd.automount

What's the advantage of adding both of these over not adding either of those ?

[L_V]

That's not exactly what I'm after, would rather there was a way to mount it from file manager, but with a password prompt ...

It is sometimes better to take more time to exactly define what you want before looking for a solution.
What you ask is exactly what a lot of applications requesting a root access are doing, and managing via policy-kit / gparted for example.

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/usr/share/polkit-1/actions/org.gnome.gparted.policy

<policyconfig>
    <vendor>The GParted Project</vendor>
    <vendor_url>https://gparted.org</vendor_url>
    <icon_name>gparted</icon_name>
    <action id="org.gnome.gparted">
        <description>Run GParted as root</description>
        <message>Authentication is required to run the GParted Partition Editor as root</message>
        <defaults>
            <allow_any>auth_admin</allow_any>
            <allow_inactive>auth_admin</allow_inactive>
            <allow_active>auth_admin</allow_active>
        </defaults>
        <annotate key="org.freedesktop.policykit.exec.path">/usr/sbin/gparted</annotate>
        <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>
    </action>
</policyconfig>

I just gave you inputs to get inspired...

Concerning "noauto,x-systemd.automount" fstab option, don't ask me to explain how fstab is interpreting auto or x-system inputs....
Found with some look around, tested, approved and fitting my need. That's it !

I even have an idea for you.....
Try to comment your shared partitions in your fstab, and see what happen.....
By default, what happen in my system is exactly what you are looking for (with Dolphin in KDE).

[niowluka]

It is sometimes better to take more time to exactly define what you want before looking for a solution.

I thought I was being pretty clear on what I want - I'd like to be able to mount the mountpoints from fstab from a file manager, without systemd mounting them automatically at boot. Apologies if that didn't come out in the post.

Concerning "noauto,x-systemd.automount" fstab option, don't ask me to explain how fstab is interpreting auto or x-system inputs....

I didn't and I wasn't going to. I asked why you think this is better, as I don't see any advantage. In both cases the drives will be mounted automatically at boot by systemd.

I even have an idea for you.....
Try to comment your shared partitions in your fstab, and see what happen.....
By default, what happen in my system is exactly what you are looking for (with Dolphin in KDE).

It'll be the same as before I started editing the fstab in the first place, won't it ?

Will look into the polkit, but seems like an overkill, especially considering how easy it was before systemd ... Like I said, I could live with user in fstab for this one.

Any ideas about the other issues ?

[L_V]

I didn't and I wasn't going to. I asked why you think this is better, as I don't see any advantage. In both cases the drives will be mounted automatically at boot by systemd.

You ask, but don't experiment enough.
What was working with "auto" for Strecth was not working for Buster anymore, and this is why I have introduced x-systemd.automount in fstab.
It is not because it is "better", but because it works.
This is for a partition I want to mount at boot.

Now, for a partition which is not in the fstab, I just tell you that without doing anything, this partition is visible in Dolphin, and if I click on it, a pop-up window will request a password.
I understood this is what your were looking for.
Now, if you don't have the same behaviour, may be "thunar" I never used does not work the same as Dolphin. I never used gnome.

May be policykit-1-gnome can help you to investigate.

[niowluka]

You ask, but don't experiment enough.

I'm new here, I'll ignore that.

[L_V]

policykit-1-gnome / investigation for gnome users

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/usr/share/doc/policykit-1-gnome/README
/etc/xdg/autostart/polkit-gnome-authentication-agent-1.desktop
/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1