我刚刚使用以下命令加密了外部硬盘驱动器的 ext4 分区：
sudo cryptsetup reencrypt --encrypt /dev/sda2 --reduce-device-size 16MiB -N
这已成功完成，如果我尝试再次运行它，它会显示：
Device /dev/sda2 is already LUKS device. Aborting operation.
到目前为止，一切都很好。现在让我们尝试打开 luks 分区：
sudo cryptsetup luksOpen /dev/sda2 mediamapthing
这有效。但是当我运行这个时：
sudo mount /dev/mapper/mediamapthing /media/media
我收到此错误：
mount: /media/media: special device /dev/mapper/mediamapthing does not exist.
我的猜测是第一个命令以某种方式破坏了我的文件系统（可能是--reduce-device-size），但我想知道这是否可以恢复/我只是运行了错误的命令来安装它。
在 dmesg 中我看到的是这样的：
[ 2260.777750] /dev/mapper/mediamapthing: Can't open blockdev
这不是很有帮助。
我的 fstab 中没有与此驱动器相关的任何内容：
UUID=21c04bb1-7cf9-491c-82a2-57222bbf5fb0 / ext4 rw,relatime 0 1
UUID=34a4e502-bd77-40e3-ace1-c1df54c531c3 /home ext4 rw,relatime 0 1
UUID=B4A8-67EE /boot vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 2
更多信息：
$ sudo systemctl status dev-mapper-mediamapthing.device systemd-cryptsetup@mediamapthing
Unit [email protected] could not be found.
● dev-mapper-mediamapthing.device - /dev/mapper/mediamapthing
Follows: unit currently follows state of sys-devices-virtual-block-dm\x2d0.device
Loaded: loaded
Active: active (plugged) since Tue 2022-11-01 12:21:49 PDT; 4min 46s ago
Until: Tue 2022-11-01 12:21:49 PDT; 4min 46s ago
Device: /sys/devices/virtual/block/dm-0
$ sudo dmsetup table
mediamapthing: 0 4334788608 crypt aes-xts-plain64 :64:logon:cryptsetup:1186f7eb-b29a-46b7-bd1d-c69446f53c47-d0 0 8:2 16384
$ sudo cryptsetup status /dev/mapper/mediamapthing
/dev/mapper/mediamapthing is active.
type: LUKS2
cipher: aes-xts-plain64
keysize: 512 bits
key location: keyring
device: /dev/sda2
sector size: 512
offset: 16384 sectors
size: 4334788608 sectors
mode: read/write
$ sudo cryptsetup luksDump /dev/sda2
LUKS header information
Version: 2
Epoch: 529153
Metadata area: 16384 [bytes]
Keyslots area: 8355840 [bytes]
UUID: 1186f7eb-b29a-46b7-bd1d-c69446f53c47
Label: (no label)
Subsystem: (no subsystem)
Flags: (no flags)
Data segments:
0: crypt
offset: 8388608 [bytes]
length: (whole device)
cipher: <redacted>
sector: 512 [bytes]
Keyslots:
0: luks2
Key: 512 bits
Priority: normal
Cipher: aes-xts-plain64
Cipher key: 512 bits
PBKDF: argon2id
Time cost: 7
Memory: 1048576
Threads: 4
Salt: <redacted>
AF stripes: 4000
AF hash: sha256
Area offset:32768 [bytes]
Area length:258048 [bytes]
Digest ID: 0
Tokens:
Digests:
0: pbkdf2
Hash: sha256
Iterations: 142160
Salt: <redacted>
Digest: <redacted>
$ blkid
/dev/mapper/mediamapthing: LABEL="stuff" UUID="238b30f9-0f23-43b6-9ebe-8389943dd5fb" BLOCK_SIZE="4096" TYPE="ext4"
$ file -sL /dev/mapper/* /dev/dm-*
/dev/mapper/mediamapthing: Linux rev 1.0 ext4 filesystem data, UUID=238b30f9-0f23-43b6-9ebe-8389943dd5fb, volume name "stuff" (errors) (extents) (64bit) (large files) (huge files)
/dev/dm-0: Linux rev 1.0 ext4 filesystem data, UUID=238b30f9-0f23-43b6-9ebe-8389943dd5fb, volume name "stuff" (errors) (extents) (64bit) (large files) (huge files)