Re: [PATCH 3/5] cryptomount luks allow multiple passphrase attempts

[John Lane <grub@jelmail.com>]

When opening a LUKS volume the user has 2 chances to supply a correct
passphrase.

if the first attempt fails then the passphrase prompt appears again.
if keyfile given then the first attempt is the uses that instead of
prompting; failure will then prompt the user for a passphrase.

This does not apply to plain mode because there is no way to know that a
key is incorrect in plain mode. Whatever key or passphrase is given will
succeed (but the unlocked data may appear as garbage, of course.).
That's inherent in the implementation of plain mode.