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

[Lennart Poettering]

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