[RFT 1/4] guestfs: fix custom image partition not expanded after disk resize

[Luis Chamberlain <mcgrof@kernel.org>]

The commit e46bf3cd54de ("guestfs: add unified LIBVIRT_IMAGE_SIZE
configuration") added disk resizing for custom images but only resized
the disk image file, not the partition inside. This resulted in VMs
having a 20GB disk but only a 2.9GB root filesystem partition, causing
out-of-space errors during kernel installation.

Add virt-resize step after qemu-img resize to expand the root partition
(/dev/sda1) to use the full disk space. This ensures VMs get the full
20GB root filesystem as intended.

Without this fix, VMs show:
  /dev/vda1  2.8G  (despite 20GB disk)

With this fix, VMs will have:
  /dev/vda1  20G  (using full disk)

Fixes: e46bf3cd54de ("guestfs: add unified LIBVIRT_IMAGE_SIZE configuration")
Generated-by: Claude AI
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 .../roles/base_image/tasks/custom-image.yml   | 31 ++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/playbooks/roles/base_image/tasks/custom-image.yml b/playbooks/roles/base_image/tasks/custom-image.yml
index 46701e75..207a5fa1 100644
--- a/playbooks/roles/base_image/tasks/custom-image.yml
+++ b/playbooks/roles/base_image/tasks/custom-image.yml
@@ -53,7 +53,36 @@
     cmd: "qemu-img resize {{ custom_image }} {{ libvirt_image_size }}"
   changed_when: true
   when:
-    - custom_image_download is changed or custom_image_stat.stat.exists
+    - custom_image_download is changed
+    - guestfs_has_custom_raw_image_url|bool
+
+- name: Create temporary file for partition-expanded image
+  ansible.builtin.tempfile:
+    state: file
+    suffix: .raw
+  register: temp_resized_image
+  when:
+    - custom_image_download is changed
+    - guestfs_has_custom_raw_image_url|bool
+
+- name: Expand root partition to use full disk
+  become: true
+  become_method: ansible.builtin.sudo
+  ansible.builtin.command:
+    cmd: "virt-resize --expand /dev/sda1 {{ custom_image }} {{ temp_resized_image.path }}"
+  changed_when: true
+  when:
+    - custom_image_download is changed
+    - guestfs_has_custom_raw_image_url|bool
+
+- name: Replace original image with partition-expanded one
+  become: true
+  become_method: ansible.builtin.sudo
+  ansible.builtin.command:
+    cmd: "mv -f {{ temp_resized_image.path }} {{ custom_image }}"
+  changed_when: true
+  when:
+    - custom_image_download is changed
     - guestfs_has_custom_raw_image_url|bool
 
 - name: Check if the custom image sentinel file already exists
-- 
2.50.1