[systemd-devel] How to use systemd-growfs* services with GPT automount

[Nils Kattenbeck]

Hi Lennart,

thanks for the information. I finally found out the true cause,
however, and it's just stupidity on my part.
While Debian (my mkosi base) does ship systemd-growfs and the man
pages for all the services, it does not ship the services themselves.
So I guess that the auto-grow functionality can never be activated.

Do you happen to know if it just starts to work magically if I add
those service files to the filesystem on my own? Or is this something
which can be compiled out?

King regards, Nils

On Wed, Oct 25, 2023 at 9:57 AM Lennart Poettering
<lennart at poettering.net> wrote:
>
> On Di, 24.10.23 23:48, Nils Kattenbeck (nilskemail at gmail.com) wrote:
>
> > > On Mo, 23.10.23 02:00, Nils Kattenbeck (nilskemail at gmail.com) wrote:
> > >
> > > > Hello,
> > > >
> > > > I am not sure how to get systemd-growfs-root.service to work with
> > > > automount. The partitions are configured via systemd-repart (and the
> > > > image created using mkosi). While the partitions are correctly grown
> > > > upon boot, the contained filesystem is not grown to match the
> > > > partition even though GrowFileSystem defaults to true. Is there
> > > > anything I am missing or an easy way to troubleshoot this and get more
> > > > information?
> > > >
> > > > One thing I notice is that the generator.late/-.mount unit has a
> > > > Options=ro which as per documentation prevents growing the filesystem.
> > > > However, the filesystem is actually mounted read-write so I assume
> > > > this is just an artifact of the initrd. Is it not possible to grow the
> > > > filesystem from which the initrd starts?
> > >
> > > Do you have "ro" or "rw" on the kernel cmdline?
> >
> > I have neither set on the cmdline.
>
> if you add it, does it work?
>
> ro/rw is a bit weird. Usually in our configuration model the settings
> on the kernel cmdline args take precedence over config in
> /etc/. But ro/rw is different for historical reasons: it only
> specifies the initial ro/rw state of the disks, expecting that
> /etc/fstab later changes things to the final setting. And if neither
> are specified we imply "ro".
>
> Hence, you have two choices: define an /etc/fstab (which of course is
> not what you want with gpt-auto) or just add "rw" to the kernel cmdline.
>
> Lennart
>
> --
> Lennart Poettering, Berlin