Comment # 7 on bug 1175908 from Franck Bui

(In reply to Harald Koenig from comment #0)
> Aug 28 21:13:32 hl systemd-cryptsetup[433]: device-mapper: reload ioctl on  
> failed: No such file or directory

That's probably a message emitted by libcryptsetup.

Can you show the content of /etc/crypttab ?

Can you try to attach your encrypted root device with cryptsetup(8) directly
for the failing case (assuming that the emergency shell is started) ?