LVM自动映射导致的Arch安装失败

TL;DR（太长不看版）

关键错误信息：ERROR: unable to open /dev/sda2: Device or resource busy

解决方案：

dmsetup remove ArchinstallVg-root

---

问题描述

在使用 archinstall 安装 Arch Linux 时，我启用了 LVM（逻辑卷管理），但因意外中断了安装过程。在尝试重新安装时，遇到了严重的问题，报错信息如下：

ERROR: unable to open /dev/sda2: Device or resource busy

更详细的日志输出：

  File "/usr/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/usr/lib/python3.13/site-packages/archinstall/scripts/guided.py", line 186, in <module>
    guided()
    ~~~~~~^^
  File "/usr/lib/python3.13/site-packages/archinstall/scripts/guided.py", line 182, in guided
    fs_handler.perform_filesystem_operations()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/archinstall/lib/disk/filesystem.py", line 84, in perform_filesystem_operations
    self._format_partitions(
    ~~~~~~~~~~~~~~~~~~~~~~~^
        mod.partitions,
     ^^^^^^^^^^^^^^^
        mod.device_path
     ^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/archinstall/lib/disk/filesystem.py", line 118, in _format_partitions
    device_handler.format(part_mod.safe_fs_type, part_mod.safe_dev_path)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/archinstall/lib/disk/device_handler.py", line 296, in format
    raise DiskError(msg) from err
archinstall.lib.exceptions.DiskError: Could not format /dev/sda2 with btrfs: ['/usr/bin/mkfs.btrfs', '-f', '/dev/sda2'] exited with abnormal exit code [1]: btrfs-progs v6.12
See https://btrfs.readthedocs.io for more information.

ERROR: unable to open /dev/sda2: Device or resource busy


Archinstall experienced the above error. If you think this is a bug, please report it to
https://github.com/archlinux/archinstall and include the log file "/var/log/archinstall/install.log".

Hint: To extract the log from a live ISO
curl -F'file=@/var/log/archinstall/install.log' https://0x0.st

---

排查步骤

通过以下方法尝试解决问题：

1. 移除物理卷：

   pvremove /dev/sda

   返回错误信息：Cannot use /dev/sda: device is partitioned

2. 擦除文件系统签名：

   wipefs -a /dev/sda

   返回错误信息：error: /dev/sda: probing initialization failed: Device or resource busy

3. 卸载挂载点：

   umount /dev/sda2

   但发现设备未挂载，继续排查资源占用问题。

4. 查看占用情况：

   lsof /dev/sda2

   无输出，表明没有活跃进程占用。

5. 停用卷组：

   vgchange -an

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解决方案

最终，通过以下命令解决问题：

dmsetup ls

列出活动设备映射项，发现 ArchinstallVg-root 存在。使用以下命令移除：

dmsetup remove ArchinstallVg-root

此后，重新运行安装流程问题得到解决。

---

总结

问题原因：意外中断安装后，LVM 的设备映射未被正确清理，导致设备被占用。 解决方法：手动清理设备映射。

此问题的经验教训在于，LVM 的设备管理需要谨慎操作，尤其在自动化工具意外中止的情况下，手动介入尤为重要。希望这篇记录对遇到类似问题的朋友有所帮助。