Add configurable container image sizing with support for creating and resizing ext4 images.

Signed-off-by: Richard Qin <richard.qin.x@gmail.com>

6 files changed, 101 insertions, 7 deletions

diff --git a/debian-container/README b/debian-container/README
index ef3bb97..15fd95b 100644
--- a/debian-container/README
+++ b/debian-container/README
@@ -17,6 +17,11 @@ sudo ./debian-container.sh base-create \
 
 sudo ./debian-container.sh init test-1 --tarball ./debian-stable.tar.gz
 sudo ./debian-container.sh init test-2 --tarball ./debian-stable.tar.gz
+sudo ./debian-container.sh init test-3 --size 8G --tarball ./debian-stable.tar.gz
+
+扩容容器：
+
+sudo ./debian-container.sh resize test-3 --size 12G
 
 进入容器：
 
@@ -59,6 +64,7 @@ sudo env \
 可配置的环境变量：
 
 DEBIAN_INSTANCES 实例目录
+DEBIAN_SIZE     新实例镜像大小，默认 3G
 DEBIAN_LOCK_FILE 锁文件路径
 DEBIAN_TARBALL  默认基础 tarball 路径
 DEBIAN_SUITE    Debian 版本，默认 stable
diff --git a/debian-container/debian-container.sh b/debian-container/debian-container.sh
index 6ef4133..78b0009 100755
--- a/debian-container/debian-container.sh
+++ b/debian-container/debian-container.sh
@@ -11,6 +11,7 @@ DC_DIR=$(dirname -- "$DC_SCRIPT")
 source "$DC_DIR/lib/config.sh"
 source "$DC_DIR/lib/common.sh"
 source "$DC_DIR/lib/network.sh"
+source "$DC_DIR/lib/storage.sh"
 source "$DC_DIR/lib/mount.sh"
 source "$DC_DIR/lib/container.sh"
 
@@ -27,14 +28,14 @@ esac
 dc_require_root
 
 case "$DC_ACTION" in
-  base-create|init|enter|exec|delete)
+  base-create|init|enter|exec|resize|delete)
     # 防止多个会话同时读写同一 ext4 镜像。
     dc_acquire_lock
     ;;
 esac
 
 case "$DC_ACTION" in
-  init|enter|exec|status|delete)
+  init|enter|exec|resize|status|delete)
     (($# > 0)) || dc_die "$DC_ACTION 需要实例名称。"
     dc_select_instance "$1"
     shift
@@ -54,6 +55,7 @@ case "$DC_ACTION" in
   _enter)  dc_enter_rootfs ;;
   exec)    dc_exec "$@" ;;
   _exec)   dc_exec_rootfs "$@" ;;
+  resize)  dc_resize "$@" ;;
   status)  dc_status ;;
   list)    dc_list ;;
   delete)  dc_delete ;;
diff --git a/debian-container/lib/common.sh b/debian-container/lib/common.sh
index d28948a..9fd03b4 100644
--- a/debian-container/lib/common.sh
+++ b/debian-container/lib/common.sh
@@ -53,12 +53,17 @@ dc_usage() {
   init NAME [选项]    创建指定名称的容器镜像
   enter NAME [选项]   进入指定容器
   exec NAME [选项]    在指定容器中执行命令
+  resize NAME [选项]  扩大指定容器的镜像
   status NAME         查看指定容器状态
   list                列出所有容器
   delete NAME         删除指定容器
 
 init 选项：
   --tarball PATH      从本地 tarball 初始化，跳过软件包下载
+  --size SIZE         镜像大小（默认：3G）
+
+resize 选项：
+  --size SIZE         新的镜像大小，只能扩大
 
 base-create 选项：
   --output PATH       输出 tarball 路径
@@ -73,6 +78,7 @@ base-create 选项：
 
 环境变量：
   DEBIAN_INSTANCES  实例目录（默认：当前目录/instances）
+  DEBIAN_SIZE       新实例镜像大小（默认：3G）
   DEBIAN_LOCK_FILE  锁文件路径（默认：/run/lock/debian-container.lock）
   DEBIAN_TARBALL    基础 tarball（默认：当前目录/debian-base.tar.gz）
   DEBIAN_SUITE      Debian 版本（默认：stable）
diff --git a/debian-container/lib/config.sh b/debian-container/lib/config.sh
index 0d91aad..3b59963 100644
--- a/debian-container/lib/config.sh
+++ b/debian-container/lib/config.sh
@@ -4,6 +4,7 @@
 
 # Keep instance data in the directory from which the tool is invoked for now.
 DC_INSTANCES=${DEBIAN_INSTANCES:-"$PWD/instances"}
+DC_SIZE=${DEBIAN_SIZE:-3G}
 DC_LOCK_FILE=${DEBIAN_LOCK_FILE:-/run/lock/debian-container.lock}
 DC_TARBALL=${DEBIAN_TARBALL:-"$PWD/debian-base.tar.gz"}
 DC_SUITE=${DEBIAN_SUITE:-stable}
diff --git a/debian-container/lib/container.sh b/debian-container/lib/container.sh
index 2c0aaad..eee6d76 100644
--- a/debian-container/lib/container.sh
+++ b/debian-container/lib/container.sh
@@ -4,6 +4,7 @@
 
 dc_init() {
   local tarball=
+  local size=$DC_SIZE
 
   while (($# > 0)); do
     case "$1" in
@@ -12,6 +13,11 @@ dc_init() {
         tarball=$2
         shift 2
         ;;
+      --size)
+        (($# >= 2)) || dc_die '--size 需要一个大小。'
+        size=$2
+        shift 2
+        ;;
       --help|-h)
         dc_usage
         return 0
@@ -33,9 +39,7 @@ dc_init() {
     dc_die "实例已存在：$DC_INSTANCE。请使用 enter 进入，避免覆盖容器数据。"
   fi
 
-  mkdir -p "$DC_INSTANCE_DIR" "$DC_ROOT"
-  truncate -s 3G "$DC_IMAGE"
-  mkfs.ext4 -F -q -L DEBIAN_CONTAINER "$DC_IMAGE"
+  dc_create_image "$size"
   if [[ -n "$tarball" ]]; then
     unshare --mount --propagation private -- bash "$DC_SCRIPT" _init "$DC_INSTANCE" "$tarball"
   else
@@ -44,6 +48,32 @@ dc_init() {
   echo "初始化完成。执行 sudo bash $DC_SCRIPT enter $DC_INSTANCE 进入容器。"
 }
 
+dc_resize() {
+  local size=
+
+  while (($# > 0)); do
+    case "$1" in
+      --size)
+        (($# >= 2)) || dc_die '--size 需要一个大小。'
+        size=$2
+        shift 2
+        ;;
+      --help|-h)
+        dc_usage
+        return 0
+        ;;
+      *)
+        dc_die "未知的 resize 选项：$1"
+        ;;
+    esac
+  done
+
+  [[ -n "$size" ]] || dc_die 'resize 必须指定 --size。'
+  [[ -f "$DC_IMAGE" ]] || dc_die '没有找到镜像，请先运行 init。'
+  dc_resize_image "$size"
+  echo "实例已扩容：$DC_INSTANCE，新的大小为 $size"
+}
+
 dc_init_rootfs() {
   local tarball=${1:-}
   local -a include_packages=()
@@ -236,9 +266,8 @@ dc_status() {
   echo "目录：$DC_INSTANCE_DIR"
   if [[ -f "$DC_IMAGE" ]]; then
     echo '镜像：存在'
-  else
-    echo '镜像：不存在'
   fi
+  dc_status_image
 }
 
 dc_delete() {
diff --git a/debian-container/lib/storage.sh b/debian-container/lib/storage.sh
new file mode 100644
index 0000000..e72c0b9
--- /dev/null
+++ b/debian-container/lib/storage.sh
@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-3.0-or-later
+# Copyright (C) 2026 by Richard Qin
+
+dc_create_image() {
+  local size=$1
+
+  mkdir -p "$DC_INSTANCE_DIR" "$DC_ROOT"
+  truncate -s "$size" "$DC_IMAGE"
+  mkfs.ext4 -F -q -L DEBIAN_CONTAINER "$DC_IMAGE"
+}
+
+dc_resize_image() {
+  local size=$1
+  local current_size
+  local target_size
+  local allocated_blocks
+  local block_size
+
+  dc_require_commands e2fsck findmnt numfmt resize2fs stat truncate
+  if findmnt --mountpoint "$DC_ROOT" >/dev/null 2>&1; then
+    dc_die "实例仍处于挂载状态：$DC_INSTANCE"
+  fi
+
+  current_size=$(stat -c '%s' "$DC_IMAGE")
+  target_size=$(numfmt --from=iec "$size")
+  ((target_size > current_size)) || dc_die "扩容大小必须大于当前镜像大小：$current_size bytes"
+
+  truncate -s "$size" "$DC_IMAGE"
+  if e2fsck -f -y "$DC_IMAGE"; then
+    :
+  else
+    [[ $? -eq 1 ]] || dc_die "文件系统检查失败：$DC_IMAGE"
+  fi
+  resize2fs "$DC_IMAGE"
+}
+
+dc_status_image() {
+  local allocated_blocks
+  local block_size
+
+  if [[ -f "$DC_IMAGE" ]]; then
+    allocated_blocks=$(stat -c '%b' "$DC_IMAGE")
+    block_size=$(stat -c '%B' "$DC_IMAGE")
+    echo "逻辑大小：$(stat -c '%s' "$DC_IMAGE") bytes"
+    echo "实际占用：$((allocated_blocks * block_size)) bytes"
+  else
+    echo '镜像：不存在'
+  fi
+}