Help with auto-mounting a specific file-system.

Help with auto-mounting a specific file-system.

[Raghav Gururajan]

Hello Guix!

I wanted to make use of my memory card slot in my X200-T and decided to use it to store cloned git repos. I have placed a 32GB card, with formatted btrfs file-system, with label "repo". I wanted to auto-mount this file-system at ~/repo. So I used the following in 'file-systems' section of my config.scm.

  (file-systems (append
                 (list (file-system
                         (device (uuid "1234-ABCD"))
                         (mount-point "/")
                         (type "btrfs")
                         (needed-for-boot? #t)
                         (dependencies mapped-devices))
                       (file-system
                         (device (file-system-label "repo"))
                         (mount-point "/home/user/repo")
                         (type "btrfs")
                         (needed-for-boot? #f)))
                 %base-file-systems))

Now, the setup work and the file-system 'repo' gets auto-mounted at ~/repo. But I am facing two issues:

[1] ~/repo becomes 'root protected' and stays like that.
[2] Despite declaring `(needed-for-boot? #f)`, system does not boot when the memory card is absent/unplugged.

How do I overcome these issues?

Thank you!

Regards,
RG.

Re: Help with auto-mounting a specific file-system.

[Pierre Neidhardt]

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If you are using GNOME or some high-level desktop environment, the SD
card should be automatically mounted when you insert it.

For less sophisticated desktop environments, you can starts tools like
udisksie on login, then pendrives, SD cards and the like will be
automatically mounted to /media/$USER/$VOLUMENAME.

> [1] ~/repo becomes 'root protected' and stays like that.

What do you mean?  Does `sudo chown ...` work for you?

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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Re: Help with auto-mounting a specific file-system.

[Raghav Gururajan]

Hi Pierre!

> If you are using GNOME or some high-level desktop environment, the SD
> card should be automatically mounted when you insert it.
> 
> For less sophisticated desktop environments, you can starts tools like
> udisksie on login, then pendrives, SD cards and the like will be
> automatically mounted to /media/$USER/$VOLUMENAME.

I am currently using dwm+dmenu. But I have already tried the above and it works. It is useful for general hot-swapping.

In this case, I would like to manage things with guix. And I want a specific file-system to be mounted at a specific mount-point (home directory), upon every boot.

>> [1] ~/repo becomes 'root protected' and stays like that.
> 
> What do you mean? Does `sudo chown ...` work for you?

The directory becomes writable only by root. I am able to manually change the permissions, but it resets on every boot.

Regards,
RG.

Re: Help with auto-mounting a specific file-system.

[Pierre Neidhardt]

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> In this case, I would like to manage things with guix. And I want a specific file-system to be mounted at a specific mount-point (home directory), upon every boot.

I think the best way to do this is to use Guix to set the right Udev
rules for Udisks:

https://wiki.archlinux.org/index.php/Udisks

> The directory becomes writable only by root. I am able to manually change the permissions, but it resets on every boot.

Weird, it should stick.

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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Re: Help with auto-mounting a specific file-system.

[Raghav Gururajan]

Hi Pierre!
 
> I think the best way to do this is to use Guix to set the right Udev
> rules for Udisks:
> 
> https://wiki.archlinux.org/index.php/Udisks

I thought I could use the same concept of mounting /home or /boot or /store etc., from another disk. But all these are immediately after root directory "/" and are likely to be protected. So then I should not be using this technique to mount something under user's directory "~/".

Okay, no problem. I can just do git operations by 'cd'ing to /media/foo/bar, which is mounted by udisks/udiskie.

Now, I am would like to modify udisks-service-type, to include an option like `enable-udiskie? boolean` in udisks-configuration. If it is #t, udiskie will run along with udisks service, on every start-up. Could you help me with a scheme code to achieve this?

Btw, this is not just for me. We can patch it in guix. This will be very handy for folks using light-weight DE or window-managers. :-)

Regards,
RG.

Re: Help with auto-mounting a specific file-system.

[Pierre Neidhardt]

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"Raghav Gururajan" <raghavgururajan@disroot.org> writes:

> Okay, no problem. I can just do git operations by 'cd'ing to /media/foo/bar, which is mounted by udisks/udiskie.

To clarify, you can configure udisks to mount your drives somewhere else
like your home directory.

> Now, I am would like to modify udisks-service-type, to include an
> option like `enable-udiskie? boolean` in udisks-configuration. If it
> is #t, udiskie will run along with udisks service, on every
> start-up. Could you help me with a scheme code to achieve this?

Udiskie is a user service, so I don't think it makes sense to include it
in udisks-service-type.

But you can run shepherd as user.  I have this service:

--8<---------------cut here---------------start------------->8---
(define auto-mount
  (make <service>
    #:provides '(auto-mount)
    #:start (make-system-constructor "udiskie &")
    #:stop (make-system-destructor "pkill udiskie")
    #:respawn? #t))
--8<---------------cut here---------------end--------------->8---

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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Re: Help with auto-mounting a specific file-system.

[Raghav Gururajan]

> To clarify, you can configure udisks to mount your drives somewhere else
> like your home directory.

Ah I see. Btw, guix does not use udisks to mount file-systems right?

Like mounting root file-system at "/", guix just uses mount command correct?

> Udiskie is a user service, so I don't think it makes sense to include it
> in udisks-service-type.

Oh. I have to read about types of services then. As a guess, is it the
difference between service running 'system-wide' and 'as and for that user'?

> But you can run shepherd as user.  I have this service:
> 
> --8<---------------cut here---------------start------------->8---
> (define auto-mount
>   (make <service>
>     #:provides '(auto-mount)
>     #:start (make-system-constructor "udiskie &")
>     #:stop (make-system-destructor "pkill udiskie")
>     #:respawn? #t))
> --8<---------------cut here---------------end--------------->8---

Thanks so much. Just to double check, should I put this in my config.scm?

Regards,
RG.

Re: Help with auto-mounting a specific file-system.

[Pierre Neidhardt]

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Raghav Gururajan <raghavgururajan@disroot.org> writes:

> Ah I see. Btw, guix does not use udisks to mount file-systems right?

>
> Like mounting root file-system at "/", guix just uses mount command correct?

Correct.

> Oh. I have to read about types of services then. As a guess, is it the
> difference between service running 'system-wide' and 'as and for that user'?

Correct.  For now Guix does not deal with user services.
>
>> --8<---------------cut here---------------start------------->8---
>> (define auto-mount
>>   (make <service>
>>     #:provides '(auto-mount)
>>     #:start (make-system-constructor "udiskie &")
>>     #:stop (make-system-destructor "pkill udiskie")
>>     #:respawn? #t))
>> --8<---------------cut here---------------end--------------->8---
>
> Thanks so much. Just to double check, should I put this in my config.scm?

No, since Guix does not deal with user services.
You'd put the above snippet in ~/.config/shepherd/init.scm:

--8<---------------cut here---------------start------------->8---
(register-services (list auto-mount))
(action 'shepherd 'daemonize)
(for-each start (append (list auto-mount)))
--8<---------------cut here---------------end--------------->8---

(Untested.)

See my dotfiles of a complete example:

https://gitlab.com/ambrevar/dotfiles

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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Re: Help with auto-mounting a specific file-system.

[Michael Rohleder]

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"Raghav Gururajan" <raghavgururajan@disroot.org> writes:
> Now, the setup work and the file-system 'repo' gets auto-mounted at ~/repo. But I am facing two issues:
>
> [1] ~/repo becomes 'root protected' and stays like that.
> [2] Despite declaring `(needed-for-boot? #f)`, system does not boot when the memory card is absent/unplugged.
>
> How do I overcome these issues?

I have the same problem as in [2], but for nfs.
Only work around was (mount? #f) ...

Maybe (service pam-mount-service-type) could help here, see
http://guix.gnu.org/manual/en/guix.html#PAM-Mount-Service


-- 
Wer unsere Traeume stiehlt, gibt uns den Tod.  (Konfuzius)

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