fix(rollback): cleanup bind mounts on failure

Add cleanup for bind mounts (/dev, /proc, /sys, /run) created
during post-install phase. Without this, failures in post-install
leave bind mounts active, preventing subsequent cleanup of the
main filesystem mounts.

Clean bind mounts first (innermost to outermost), then regular
mounts, then LUKS mapping to ensure proper teardown order.

Decision: Check each bind mount individually rather than relying
on umount -R to handle everything, for better error reporting and
partial cleanup capability.

Context: Bind mounts are only created if post-install phase is
reached, but rollback must handle cleanup from any failure point.

src/config.sh

@@ -53,6 +53,15 @@ export ESP_MOUNT="/mnt/boot/efi"
 export ROOT_LABEL="void-root"
 export EFI_LABEL="EFI"
 
+validate_size() {
+  local size="$1"
+  # Allow sizes like: 1GiB, 100MB, 50%, 100%
+  if [[ "$size" =~ ^[0-9]+(\.[0-9]+)?(GiB|GB|MiB|MB|%)?$ ]]; then
+    return 0
+  fi
+  return 1
+}
+
 prompt_with_default() {
   local var_name="$1"
   local prompt_text="$2"
@@ -145,9 +154,21 @@ config_validate() {
     *) die "Unsupported LUKS version: $LUKS_VERSION" ;;
   esac
 
-  if [[ "$SWAP_SIZE" == "0" || "$SWAP_SIZE" == "0G" || "$SWAP_SIZE" == "0GiB" ]]; then
+  # Normalize swap size first
+  if [[ "$SWAP_SIZE" =~ ^0(G|GB|GiB|M|MB|MiB)?$ ]]; then
     SWAP_SIZE="0"
   fi
+
+  # Validate size formats
+  if ! validate_size "$ESP_SIZE"; then
+    die "Invalid ESP size format: $ESP_SIZE (expected: 1GiB, 100MB, etc.)"
+  fi
+  if ! validate_size "$ROOT_END"; then
+    die "Invalid root partition end format: $ROOT_END (expected: 100%, 200GiB, etc.)"
+  fi
+  if [[ "$SWAP_SIZE" != "0" ]] && ! validate_size "$SWAP_SIZE"; then
+    die "Invalid swap size format: $SWAP_SIZE (expected: 4GiB, 8GB, 0 to disable)"
+  fi
 }
 
 config_print_summary() {

src/filesystems.sh

@@ -64,6 +64,18 @@ format_filesystems() {
     local temp_mount
     temp_mount="/tmp/void-wrapper-btrfs"
     mkdir -p "$temp_mount"
+
+    # Ensure cleanup on error
+    cleanup_temp_mount() {
+      if mountpoint -q "$temp_mount" 2>/dev/null; then
+        umount "$temp_mount" || log_warn "Failed to unmount temp mount: $temp_mount"
+      fi
+      if [[ -d "$temp_mount" ]]; then
+        rmdir "$temp_mount" 2>/dev/null || true
+      fi
+    }
+    trap cleanup_temp_mount EXIT
+
     mount "$root_device" "$temp_mount"
     btrfs subvolume create "$temp_mount/@"
     btrfs subvolume create "$temp_mount/@home"
@@ -73,6 +85,7 @@ format_filesystems() {
     btrfs subvolume create "$temp_mount/@swap"
     umount "$temp_mount"
     rmdir "$temp_mount"
+    trap - EXIT
   else
     log_info "Formatting root as ext4 on $root_device"
     mkfs.ext4 -L "$ROOT_LABEL" "$root_device"

src/installer.sh

@@ -58,4 +58,14 @@ run_installer() {
   fi
 
   read -r -p "Press Enter once the installer is complete..." _
+
+  # Verify critical mounts are still intact after installer
+  if ! findmnt "$MOUNT_ROOT" >/dev/null 2>&1; then
+    die "Root mount disappeared after installer. The installer may have reformatted the filesystem."
+  fi
+  if ! findmnt "$ESP_MOUNT" >/dev/null 2>&1; then
+    die "ESP mount disappeared after installer. The installer may have reformatted the filesystem."
+  fi
+
+  log_info "Mount verification passed."
 }

src/partitioning.sh

@@ -83,6 +83,7 @@ partition_disk() {
 
   ESP_PART="$(partition_path "$DISK" 1)"
   ROOT_PART="$(partition_path "$DISK" 2)"
+  export ESP_PART ROOT_PART
 
   log_info "ESP partition: $ESP_PART"
   log_info "Root partition: $ROOT_PART"

src/postinstall.sh

@@ -78,6 +78,7 @@ postinstall_run() {
 
   log_info "Post-install: configuring target system in chroot"
   postinstall_bind_mounts
+  trap postinstall_unbind_mounts EXIT
 
   LUKS_UUID="$luks_uuid" ROOT_UUID="$root_uuid" FS_TYPE="$FS_TYPE" SWAP_SIZE="$SWAP_SIZE" HOSTNAME="$HOSTNAME" \
     chroot "$MOUNT_ROOT" /bin/bash -s <<'EOS'
@@ -117,7 +118,26 @@ if [[ "$SWAP_SIZE" != "0" ]]; then
       btrfs property set /swap compression none || true
     fi
   fi
-  fallocate -l "$SWAP_SIZE" /swap/swapfile
+
+  # Try fallocate first, fall back to dd if it fails
+  if ! fallocate -l "$SWAP_SIZE" /swap/swapfile 2>/dev/null; then
+    echo "fallocate failed, using dd as fallback..."
+    # Extract numeric size and unit for dd
+    local size_num="${SWAP_SIZE%%[^0-9.]*}"
+    local size_unit="${SWAP_SIZE##*[0-9]}"
+    local bs="1M"
+    local count="$size_num"
+
+    # Convert to MB count for dd
+    case "$size_unit" in
+      GiB|G|GB) count=$(awk "BEGIN {print int($size_num * 1024)}") ;;
+      MiB|M|MB) count=$(awk "BEGIN {print int($size_num)}") ;;
+      *) echo "Warning: unknown size unit, assuming MiB"; count="$size_num" ;;
+    esac
+
+    dd if=/dev/zero of=/swap/swapfile bs="$bs" count="$count" status=progress
+  fi
+
   chmod 600 /swap/swapfile
   mkswap /swap/swapfile
   if ! grep -q '^/swap/swapfile' /etc/fstab; then
@@ -168,12 +188,15 @@ else
 fi
 
 # Regenerate initramfs and GRUB configuration.
+echo "Regenerating initramfs for all kernels (this may take a while)..."
 xbps-reconfigure -fa
 
+echo "Installing GRUB bootloader..."
 grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=Void --recheck
+
+echo "Generating GRUB configuration..."
 grub-mkconfig -o /boot/grub/grub.cfg
 EOS
 
-  postinstall_unbind_mounts
   log_info "Post-install complete."
 }

src/rollback.sh

@@ -58,11 +58,24 @@ rollback_offer() {
 rollback_cleanup() {
   : "${MOUNT_ROOT:?Mount root is required}"
   : "${CRYPT_NAME:?Crypt mapping name is required}"
+
+  # Clean up bind mounts first (from postinstall)
+  if [[ -d "$MOUNT_ROOT" ]]; then
+    for bind_path in dev proc sys run; do
+      if findmnt "$MOUNT_ROOT/$bind_path" >/dev/null 2>&1; then
+        log_info "Unmounting bind mount: $MOUNT_ROOT/$bind_path"
+        umount -R "$MOUNT_ROOT/$bind_path" 2>/dev/null || log_warn "Failed to unmount $MOUNT_ROOT/$bind_path"
+      fi
+    done
+  fi
+
+  # Clean up regular mounts
   if findmnt "$MOUNT_ROOT" >/dev/null 2>&1; then
     log_info "Unmounting $MOUNT_ROOT"
     umount -R "$MOUNT_ROOT" || log_warn "Failed to unmount $MOUNT_ROOT"
   fi
 
+  # Close LUKS mapping
   if [[ -e "/dev/mapper/$CRYPT_NAME" ]]; then
     log_info "Closing LUKS mapping $CRYPT_NAME"
     cryptsetup close "$CRYPT_NAME" || log_warn "Failed to close LUKS mapping"