Updates to allow Bigboot to decrement from the default target size, down to a minimum threshold of 1GB

tasks/check_space_fallback.yml

@@ -0,0 +1,26 @@
+---
+- name: Fail if /boot can't expand to at least 1GB
+  ansible.builtin.assert:
+    that: bigboot_size_target | human_to_bytes > 1073741824
+    fail_msg: "{{ bigboot_size_target | int | human_readable(unit='M') }} is less than the minimum of 1GB for /boot"
+
+- name: Verify available space and re-check if needed
+  block:
+    - name: Assert that there is space on the logical volume for shrinkage
+      ansible.builtin.assert:
+        that: bigboot_lv_info['size_available'] > bigboot_expansion_diff | int
+        fail_msg: There is not enough space available for LV shrinking.
+
+  rescue:
+    - name: Decrement size target by .25G
+      ansible.builtin.set_fact:
+        bigboot_size_target: "{{ bigboot_size_target | human_to_bytes - 262144000 }}"
+
+    - name: Update required expansion space
+      ansible.builtin.set_fact:
+        bigboot_expansion_diff:
+          "{{ bigboot_size_target | human_to_bytes - bigboot_boot_partsize | human_to_bytes }}"
+
+    - name: Re-check disk space - RESCUE
+      ansible.builtin.include_tasks: check_space_fallback.yml
+