From af38c279daaea45fcb35ab5370c2b8032e2cf5f4 Mon Sep 17 00:00:00 2001
From: Chris Hammer <chris@thezengarden.net>
Date: Mon, 14 Oct 2024 14:24:28 -0400
Subject: [PATCH] add pvsqueeze.sh script, and execute it prior to ALL bigboot
 executions

---
 bigboot_execute_resize.yml | 16 ++++++---
 scripts/pvsqueeze.sh       | 68 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 5 deletions(-)
 create mode 100644 scripts/pvsqueeze.sh

diff --git a/bigboot_execute_resize.yml b/bigboot_execute_resize.yml
index 3f2c3b1..1274d3a 100644
--- a/bigboot_execute_resize.yml
+++ b/bigboot_execute_resize.yml
@@ -31,13 +31,19 @@
       when:
         - bigboot_data[inventory_hostname]['bigboot_execute_shrink_lv'] | default(false) | bool
 
-    - name: Expand the /boot partition as requested
-      ansible.builtin.import_role:
-        name: infra.lvm_snapshots.bigboot
-      vars:
-        bigboot_partition_size: "{{ bigboot_size_target }}"
+    - name: Shift free extents and expand /boot
       when:
         - bigboot_data[inventory_hostname]['bigboot_execute_bigboot'] | bool
+      block:
+        - name: Shift free extents to end of PV
+          ansible.builtin.script: "scripts/pvsqueeze.sh {{ bigboot_data[inventory_hostname]['bigboot_pv'] }}"
+          register: bigboot_pvsqueeze
+
+        - name: Expand the /boot partition as requested
+          ansible.builtin.import_role:
+            name: infra.lvm_snapshots.bigboot
+          vars:
+            bigboot_partition_size: "{{ bigboot_size_target }}"
 
     - name: Restore service state for disabled services
       ansible.builtin.import_tasks: tasks/restore_services.yml
diff --git a/scripts/pvsqueeze.sh b/scripts/pvsqueeze.sh
new file mode 100644
index 0000000..05b762a
--- /dev/null
+++ b/scripts/pvsqueeze.sh
@@ -0,0 +1,68 @@
+#!/bin/bash
+#
+# pvsqueeze - Squeeze PEs into free holes
+#
+# This script iteratively moves linear (allocated to LV) PEs to fill in free
+# holes found in a PV segement map. The end result is that all free PEs are
+# at the end of the PV. Use this script as required in anger!
+#
+
+# Usage
+if [[ ! $1 =~ ^/dev/ ]]; then
+  echo "Usage: $0 PV"
+  exit 1
+fi
+
+# Set some vars
+pvdev=$1
+pvsargs='--noheadings --nameprefixes --segments -o pvseg_start,pvseg_size,segtype'
+
+# Show current segment map
+echo 'PV segment map before squeeze:'
+pvs "$pvdev" --segments -o lvname,pvseg_start,pvseg_size,seg_le_ranges
+if [[ $? -ne 0 ]]; then
+  echo "$0: Fatal error getting PV info"
+  exit 1
+fi
+
+# Iterate stuffing PEs in each free hole
+while true; do
+  # Find first free segment
+  LVM2_PVSEG_START=
+  eval $(pvs "$pvdev" $pvsargs | grep SEGTYPE=.free. | head -1)
+  if [[ -z $LVM2_PVSEG_START ]]; then
+    echo "$0: No free segments found"
+    exit 1
+  fi
+  free_start=$LVM2_PVSEG_START
+  free_size=$LVM2_PVSEG_SIZE
+
+  # Find the last linear segment
+  LVM2_PVSEG_START=
+  eval $(pvs "$pvdev" $pvsargs | grep SEGTYPE=.linear. | tail -1)
+    if [[ -z $LVM2_PVSEG_START ]]; then
+    echo "$0: No linear segments found"
+    exit 1
+  fi
+  move_start=$LVM2_PVSEG_START
+  move_size=$LVM2_PVSEG_SIZE
+
+  # We're done when first free is after the last linear
+  [[ $free_start -gt $move_start ]] && break
+
+  # Move last linear PEs to the free segment
+  from_range="$pvdev:$((move_start+move_size-free_size))-$((move_start+move_size-1))"
+  to_range="$pvdev:$((free_start))-$((free_start+free_size))"
+  echo "Moving $from_range to $to_range..."
+  pvmove --atomic --alloc anywhere "$from_range" "$to_range"
+  if [[ $? -ne 0 ]]; then
+    echo "$0: Fatal error doing pvmove"
+    exit 1
+  fi
+done
+
+# Show squeezed segment map
+echo 'PV segment map after squeeze:'
+pvs "$pvdev" --segments -o lvname,pvseg_start,pvseg_size,seg_le_ranges
+
+exit 0