[systemd-devel] systemd-gpt-auto-generator does not appear to remount rootfs rw

Dimitri John Ledkov dimitri.j.ledkov at intel.com
Tue Dec 23 08:56:35 PST 2014

I'm using systemd 218 (stock upstream, unpatched) & dracut 040 (stock
upstream, unpatched).

I'm trying to build a basic GPT disk image to boot in a VM with
gpt-auto-generator discovery of partitions.

I create three partitions: ESP, swap and rootfs with the following type ids set:
sgdisk /dev/loop6 --typecode=1:c12a7328-f81f-11d2-ba4b-00a0c93ec93b
sgdisk /dev/loop6 --typecode=2:0657fd6d-a4ab-43c4-84e5-0933c84b4f4f
sgdisk /dev/loop6 --typecode=3:4f68bce3-e8cd-4db1-96e7-fbcaf984b709

In addition to that I clear the no-auto-mount and read-only attributes:
sgdisk /dev/loop6 --attributes=1:clear:60
sgdisk /dev/loop6 --attributes=1:clear:63
sgdisk /dev/loop6 --attributes=3:clear:60
sgdisk /dev/loop6 --attributes=3:clear:63

Thus I am expecting for the gpt-auto-generator to work correctly.

It does boot with and without initramfs, however in such configuration
the root filesystem (3rd partition in this case) is mounted read-only
and a few of standard systemd units fail. As per documentation, I had
the impression that rootfs should be mounted read-write in such

To mitigated this problem I came up with two workarounds:
* add "rw" to the kernel cmdline
* add /etc/fstab with a single entry like this one:
/dev/gpt-auto-root / none       defaults,rw

Is this correct additional requirements to get "rw" rootfs? Or is
there a bug, and either of the workarounds are not required? Or are my
type ids/attributes set wrongly on the partitions?

Ho Ho Ho,


Intel Corporation (UK) Ltd. - Co. Reg. #1134945 - Pipers Way, Swindon SN3 1RJ.

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