Mounting Luks Container?

Is there a simple way to mount a Luks container via unraid? 

I have an image file.   Before I went to unraid, I would simply 

Cryptesetup open luks blahblah.img blahblah

then mount /dev/mapper/blahblah foldername

I do that now in unraid.  SSH in and do that.  Mount it to a share I made on unraid.  I am able to view it and everything works.   The CATCH is when I go to unmount it

umount /mnt/user/blahblah   then luksClose /dev/mapper/blahblah......................   it just says it is busy

I have made sure I don't have the folder open anywhere.  It seems after an extended amount of time.  It FINALLY release and I can unmount the folder.    Then after another really long time, I can then luksClose the container.    

I am not sure how Unraid handles the file, especially since I mount it from terminal.   Or.......... How do I kill the session?   Force linux to let go of folder so I can unmount and close?

Or, is there some sort of plugin I can do all this with?   

Thanks