bug#31752: 'guix system disk-image --file-system-type=iso9660' is broken

[Ludovic Courtès]

Here’s what I get:

--8<---------------cut here---------------start------------->8---
$ guix system disk-image --file-system-type=iso9660 
gnu/system/examples/bare-bones.tmpl
[…]
environment variable `PATH' set to 
`/gnu/store/fc24iwkx64d05rjmay734arc0z4izdl9-qemu-minimal-2.12.0/bin:/gnu/store/zr3lz229a9p2xs2daapkkf8d46ihppn7-parted-3.2'
error: failed to evaluate directive: (directory "/gnu/store" 0 30000)
error: failed to evaluate directive: (directory "/gnu/store" 0 30000 1021)
In ./gnu/build/linux-boot.scm:
   530:13  6 (_)
In unknown file:
           5 (primitive-load "/gnu/store/v1v98cplv1ra7hqp8p11v2pzssl���")
           4 (primitive-load "/gnu/store/hgwy4w3y0801napx28z6dpjrzs3���")
In ice-9/eval.scm:
    619:8  3 (_ #(#<directory (guile-user) 25b2140> ("/gnu/sto���" ���) ���))
In ./gnu/build/vm.scm:
    411:4  2 (make-iso9660-image _ "/gnu/store/iiilhj85499zxp8fp3nn���" ���)
In ./gnu/build/install.scm:
    129:2  1 (populate-root-file-system "/gnu/store/98a0qs63d79djaf���" ���)
In ice-9/boot-9.scm:
   260:13  0 (for-each #<procedure 255cd60 at ./gnu/build/install.s���> ���)
In procedure chown: Operation not permitted
[    0.956489] Kernel panic - not syncing: Attempted to kill init! 
exitcode=0x00000000
--8<---------------cut here---------------end--------------->8---

The code in the VM is running as root, yet (mkdir-p
"/tmp/root/gnu/store") creates those directories with UID 30001.

Needs more investigation…

Ludo’.