use mount with LUKS2

Back in times of LUKS1, it was possible to use a command like

$ mount /dev/luks-encrypted-partition /mnt/a 
[enter passphrase upon being prompted] 

as a shortcut for

$ cryptsetup luksOpen /dev/luks-encrypted-partition some-name
$ mount /dev/mapper/some-name /mnt/a

But since LUKS2 this ability is lost. Directly trying to mount a LUKS2 encrypted partition results in the following error message:

$ mount /dev/luks-encrypted-partition /mnt/a
mount: /mnt/a: unknown filesystem type 'crypto_LUKS'. 

Does anyone know how I can get back to the old functionality? I am using an up-to-date Arch Linux system.

Automatic mounting of encrypted partition is possible by helper program mount.crypt, which is part of libpam_mount_bin package. The support for LUKS2 in libpam_mount was introduced in version libpam-mount-2.16-5ubuntu0.1 in 2019 (see https://bugs.launchpad.net/ubuntu/+source/libpam-mount/+bug/1804408 ).

So, the error you encounter is not due to lack of LUKS2 support. I had similar problem after upgrade of (K)ubuntu 18.04 to 20.04 probably because helper program mount.crypt and symlinks mount.crypt_LUKS and mount.crypto_LUKS are now part of libpam-mount-bin package and not libpam-mount, and this package was not installed during upgrade. The hint about package change comes from https://forums.linuxmint.com/viewtopic.php?t=324991 .

Check if you have the mount helper program installed.