我有一台带有加密主分区的 ubuntu 18.04 机器，主目录是使用 rsnapshot 备份的。因此，例如，我的 rsnapshot 驱动器中有以下目录结构：
darren@hepburn ~ $ ls -al /mnt/snapshots/hourly.0/hepburn/home/.ecryptfs/darren/
total 60
drwxr-xr-x 4 darren darren 4096 Apr 7 15:15 .
drwxr-xr-x 4 root root 4096 Nov 10 2015 ..
drwx------ 2 darren darren 4096 Nov 1 2015 .ecryptfs
-rw-rw-r-- 1 darren darren 1278 Apr 7 15:15 .encfs6.xml
drwx------ 145 darren darren 45056 Apr 7 11:50 .Private
如果我尝试挂载备份目录以检索文件，我不会从 encfs 收到任何错误，但在挂载目录中看不到任何文件：
darren@hepburn ~ $ encfs -v /mnt/snapshots/hourly.0/hepburn/home/.ecryptfs/darren/ /tmp/backup
VER Root directory: /mnt/snapshots/hourly.0/hepburn/home/.ecryptfs/darren/ [main.cpp:540]
VER Fuse arguments: (daemon) (threaded) (keyCheck) encfs /tmp/backup/ -o use_ino -o default_permissions [main.cpp:541]
VER found new serialization format [FileUtils.cpp:294]
VER subVersion = 20100713 [FileUtils.cpp:308]
VER checking if ssl/aes(3:0:2) implements ssl/aes(3:0) [Interface.cpp:110]
VER allocated cipher ssl/aes, keySize 32, ivlength 16 [SSL_Cipher.cpp:333]
VER useStdin: 0 [FileUtils.cpp:1588]
EncFS Password:
VER checking if ssl/aes(3:0:2) implements ssl/aes(3:0) [Interface.cpp:110]
VER allocated cipher ssl/aes, keySize 32, ivlength 16 [SSL_Cipher.cpp:333]
VER cipher key size = 52 [FileUtils.cpp:1596]
VER checking if nameio/block(4:0:2) implements nameio/block(4:0) [Interface.cpp:110]
darren@hepburn ~ $ ls -al /tmp/backup/
total 68
drwxr-xr-x 4 darren darren 4096 Apr 7 15:15 .
drwxrwxrwt 35 root root 61440 Apr 7 15:50 ..
这不是密码问题，如果我使用错误的密码，我会被告知：
...
EncFS Password:
VER checking if ssl/aes(3:0:2) implements ssl/aes(3:0) [Interface.cpp:110]
VER allocated cipher ssl/aes, keySize 32, ivlength 16 [SSL_Cipher.cpp:333]
VER cipher key size = 52 [FileUtils.cpp:1596]
VER checksum mismatch: expected 3670270093, got 4217147638 [SSL_Cipher.cpp:541]
VER on decode of 48 bytes [SSL_Cipher.cpp:543]
Error decoding volume key, password incorrect
我在这里做错了什么？