XFS - bad primary superblock - bad magic number !!!

[Panagiotis Atmatzidis <p.atmatzidis@xxxxxxxxx>]

Hi there,

I have a Gentoo GNU/Linux home file server. This server has a / with 
reiserFS and 3 hd's with XFS which are used for storage. The 3 HD's are 
encrypted xfs filelsystems. The filesystems dmsetup links are:
enc-a, enc-b, enc-c

I had houndreds of hard-reboots for several reasons for ~ 3 years and 
never had problems with data loss etc.
Today though, when I came back.. I saw the Linux server turned off and 
when I booted the machine I saw the following error msg for enc-a & 
enc-b. enc-c is alright (files are there and it's mount-able, I see no 
errors on xfs_repair /dev/mapper/enc-c):
#xfs_repair -n /dev/mapper/enc-a
Phase 1 - find and verify superblock...
bad primary superblock - bad magic number !!!

attempting to find secondary superblock...
(this one goes for ever without an end until now)

is there any way to save this?

thank you.