fix(post-install): prioritize ZRAM ahead of disk swap

scripts/post_install/zram_profile_helpers.sh

@@ -1,6 +1,12 @@
 #!/usr/bin/env bash
 # Pure helpers shared by the ZRAM installer and its fixture tests.
 
+# The kernel's maximum priority puts ZRAM ahead of standard Proxmox swap.
+# A disk swap explicitly configured at this same maximum cannot be outranked.
+if ! declare -p ZRAM_SWAP_PRIORITY >/dev/null 2>&1; then
+    readonly ZRAM_SWAP_PRIORITY=32767
+fi
+
 zram_render_generator_config() {
     local algorithm=zstd
     [[ "${1:-false}" == true ]] && algorithm='zstd(level=9)'
@@ -9,19 +15,32 @@ zram_render_generator_config() {
 [zram0]
 zram-size = ram / 10
 compression-algorithm = $algorithm
-swap-priority = 100
+swap-priority = $ZRAM_SWAP_PRIORITY
 EOF
 }
 
-zram_list_non_zram_swap() {
-    local swaps_file="$1" fstab_file="$2"
-    awk 'NR > 1 && $1 !~ /^\/dev\/zram[0-9]+$/ { print "active: " $1 }' "$swaps_file"
-    awk '$0 !~ /^[[:space:]]*#/ && NF >= 3 && $3 == "swap" && $1 !~ /^\/dev\/zram[0-9]+$/ { print "fstab: " $1 }' "$fstab_file"
+zram_list_foreign_active_zram_swap() {
+    local swaps_file="$1" owned_device="${2:-}"
+    local swap_paths swap_path real_device
+    [[ -r "$swaps_file" ]] || return 2
+    swap_paths="$(awk 'NR > 1 { print $1 }' "$swaps_file")" || return 2
+    while IFS= read -r swap_path; do
+        [[ -z "$swap_path" ]] && continue
+        real_device="$(readlink -f -- "$swap_path" 2>/dev/null)" || real_device="$swap_path"
+        if [[ "$real_device" =~ ^/dev/zram[0-9]+$ && "$real_device" != "$owned_device" ]]; then
+            printf 'active zram: %s\n' "$swap_path"
+        fi
+    done <<< "$swap_paths"
 }
 
-zram_has_non_zram_swap() {
-    [[ -r "$1" && -r "$2" ]] || return 2
-    [[ -n "$(zram_list_non_zram_swap "$1" "$2")" ]]
+zram_list_foreign_fstab_zram_swap() {
+    local fstab_file="$1"
+    [[ -r "$fstab_file" ]] || return 2
+    awk '
+        $0 !~ /^[[:space:]]*#/ && NF >= 3 && $3 == "swap" && $1 ~ /^\/dev\/zram[0-9]+$/ {
+            print "fstab zram: " $1
+        }
+    ' "$fstab_file"
 }
 
 # Print generator configuration outside this feature's dedicated drop-in.
@@ -37,7 +56,8 @@ zram_foreign_generator_config() {
             [[ "$file" == "$owned_file" ]] && continue
             # Ignore package defaults containing only comments, whitespace and
             # section headers. Any directive or malformed active line is foreign.
-            if awk '
+            local active
+            active="$(awk '
                 {
                     line=$0
                     sub(/^[[:space:]]+/, "", line)
@@ -45,27 +65,70 @@ zram_foreign_generator_config() {
                     if (line == "" || line ~ /^[#;]/ || line ~ /^\[[^]]+\]$/) next
                     found=1
                 }
-                END { exit !found }
-            ' "$file"; then
+                END { if (found) print "active" }
+            ' "$file")" || return 2
+            if [[ -n "$active" ]]; then
                 printf '%s\n' "$file"
             fi
         done
     done
 }
 
-zram_list_defined_systemd_swap_units() {
-    local fixture_root="${1:-}" root file
-    local roots=(/etc/systemd/system /run/systemd/system)
+zram_list_foreign_systemd_zram_units() {
+    local fixture_root="${1:-}" root file unit what unit_files
+    local roots=(/etc/systemd/system /run/systemd/system /usr/local/lib/systemd/system /usr/lib/systemd/system /lib/systemd/system)
     if [[ -n "$fixture_root" ]]; then
-        roots=("$fixture_root/etc/systemd/system" "$fixture_root/run/systemd/system")
+        roots=("$fixture_root/etc/systemd/system" "$fixture_root/run/systemd/system" "$fixture_root/usr/local/lib/systemd/system" "$fixture_root/usr/lib/systemd/system" "$fixture_root/lib/systemd/system")
     fi
     for root in "${roots[@]}"; do
         [[ -d "$root" ]] || continue
+        # Skip activation links; systemd-generator creates links under
+        # *.wants and they must not look like foreign unit definitions.
+        unit_files="$(find "$root" \( -type d \( -name '*.wants' -o -name '*.requires' \) -prune \) -o \( \( -name '*.swap' -o -path '*.swap.d/*.conf' \) \( -type f -o -type l \) -print \) 2>/dev/null)" || return 2
         while IFS= read -r file; do
-            # Files in these roots are administrator-defined units. The
-            # generator's own output lives under /run/systemd/generator and
-            # is intentionally outside this scan.
-            printf 'systemd: %s\n' "$file"
-        done < <(find "$root" -name '*.swap' \( -type f -o -type l \) -print 2>/dev/null)
+            [[ -z "$file" ]] && continue
+            unit="$(basename "$file")"
+            if [[ -L "$file" && "$(readlink -f -- "$file" 2>/dev/null || true)" == /dev/null ]]; then
+                if [[ "$unit" == "dev-zram0.swap" ]]; then
+                    printf 'systemd zram unit masked: %s\n' "$file"
+                fi
+                continue
+            fi
+            # A persistent unit named for a zram device could shadow the
+            # generated unit, even if it currently points at another device.
+            what="$(awk '
+                /^[[:space:]]*\[Swap\][[:space:]]*$/ { in_swap=1; next }
+                /^[[:space:]]*\[/ { in_swap=0 }
+                in_swap && /^[[:space:]]*What[[:space:]]*=[[:space:]]*\/dev\/zram[0-9]+([[:space:]]|$)/ {
+                    found=1
+                }
+                END { if (found) print "zram" }
+            ' "$file")" || return 2
+            if [[ "$unit" =~ ^dev-zram[0-9]+\.swap$ || -n "$what" ]]; then
+                printf 'systemd zram unit: %s\n' "$file"
+            fi
+        done <<< "$unit_files"
     done
 }
+
+zram_profile_verify_active() {
+    local expected_algorithm="$1" expected_priority="${2:-$ZRAM_SWAP_PRIORITY}"
+    local sys_block_root="${3:-/sys/block}" meminfo_path="${4:-/proc/meminfo}" swaps_path="${5:-/proc/swaps}"
+    local zram0="$sys_block_root/zram0" expected_bytes actual_bytes active_algorithm
+
+    [[ -r "$zram0/disksize" && -r "$zram0/comp_algorithm" && -r "$meminfo_path" && -r "$swaps_path" ]] || return 1
+    expected_bytes="$(awk '/^MemTotal:/ { print int($2 * 1024 / 10) }' "$meminfo_path")"
+    actual_bytes="$(cat "$zram0/disksize")"
+    [[ "$expected_bytes" =~ ^[0-9]+$ && "$actual_bytes" =~ ^[0-9]+$ ]] || return 1
+    (( actual_bytes >= expected_bytes - 1048576 && actual_bytes <= expected_bytes + 1048576 )) || return 1
+    active_algorithm="$(grep -oE '\[[^]]+\]' "$zram0/comp_algorithm" | tr -d '[]')"
+    [[ "$active_algorithm" == "$expected_algorithm" ]] || return 1
+    awk -v priority="$expected_priority" '
+        NR > 1 && $1 == "/dev/zram0" {
+            found=1
+            if ($5 + 0 != priority + 0) bad=1
+        }
+        NR > 1 && $1 ~ /^\/dev\/zram[0-9]+$/ && $1 != "/dev/zram0" { bad=1 }
+        END { exit !(found && !bad) }
+    ' "$swaps_path"
+}