Incus delete iso error: Failed to run: btrfs subvolume delete

Incus
1

incus 6.14: After importing an iso volume:
incus storage volume import default debian-12.11.0-amd64-netinst.iso debian12-netinst --type=iso
Trying to delete it:
incus storage volume delete default custom/debian12-netinst
Gives the following error:
Error: Failed deleting subvolume "/var/lib/incus/storage-pools/default/custom/default_debian12-netinst.iso": Failed to run: btrfs subvolume delete /var/lib/incus/storage-pools/default/custom/default_debian12-netinst.iso: exit status 1 (ERROR: Not a Btrfs subvolume: Invalid argument)

2 
root@dakara:~# incus storage create foo btrfs
Storage pool foo created
root@dakara:~# incus storage volume import foo /home/stgraber/Downloads/virtio-win-0.1.271.iso virtio --type=iso
root@dakara:~# incus storage volume delete foo virtio
Storage volume virtio deleted
root@dakara:~# incus storage delete foo
Storage pool foo deleted

I know we fixed a volume naming issue related to ISO recently so there’s a good chance that your issue was already fixed in the main branch and that will be in 6.15 next week.

3

Thanks. That sounds positive.
I’ll look out 6.15, test and get back to you.

4

Apologies for the delay in reply. Alas, I still have the same error.

$ incus storage volume delete default debian12-netinst
Error: Failed deleting subvolume "/var/lib/incus/storage-pools/default/custom/default_debian12-netinst.iso": Failed to run: btrfs subvolume delete /var/lib/incus/storage-pools/default/custom/default_debian12-netinst.iso: exit status 1 (ERROR: Not a Btrfs subvolume: Invalid argument)

No files are in the directory shown in the error message although there is a root.img file in
/var/lib/incus/storage-pools/default/custom/default_iso-volume.iso

Supporting information below.

$ incus --version
6.20

$ incus storage volume list default

+-----------------+------------------+-------------+--------------+---------+
|      TYPE       |       NAME       | DESCRIPTION | CONTENT-TYPE | USED BY |
+-----------------+------------------+-------------+--------------+---------+
| custom          | debian12-netinst |             | iso          | 0       |
+-----------------+------------------+-------------+--------------+---------+

$ incus storage volume show default custom/debian12-netinst

config:
  size: "702545920"
description: ""
name: debian12-netinst
type: custom
used_by: []
location: none
content_type: iso
project: default
created_at: 2025-07-24T16:16:06.506036644+02:00

# ls -lR /var/lib/incus/storage-pools/default/custom/
/var/lib/incus/storage-pools/default/custom/:
total 0
drwx------ 1 root root  0 Jul 24 16:36 default_debian12-netinst.iso
drwx--x--x 1 root root 16 Jul 24 16:16 default_iso-volume.iso

/var/lib/incus/storage-pools/default/custom/default_debian12-netinst.iso:
total 0

/var/lib/incus/storage-pools/default/custom/default_iso-volume.iso:
total 686080
-rw------- 1 root root 702545920 Jul 24 16:16 root.img
5

The problem persists also with incus v6.22.

6

What distribution and kernel is that running on?
Also, can you show the incus storage show default output for good measure?

7

cat /proc/version

Linux version 6.1.0-44-amd64 (debian-kernel@lists.debian.org) (gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 SMP PREEMPT_DYNAMIC Debian 6.1.164-1 (2026-03-09)

incus storage show default

config:
  size: 200GiB
  source: /var/lib/incus/disks/default.img
description: ""
name: default
driver: btrfs
used_by:
- /1.0/instances/deb01
- /1.0/instances/u1
- /1.0/instances/win11dev
- /1.0/profiles/default
- /1.0/storage-pools/default/volumes/custom/debian12-netinst
status: Created
locations:
- none

Thanks @stgraber