Volume loss after power cut

Hi all!

I got a ReadyNAS 716x within a 6 disks X-RAID array

After a power failure I've lost the RAID volume, the only things I can do are to format the disks and to disable the X-RAID

This is the output of the diagnostic tool included in raidar:

2016-07-11 19:06:27: BTRFS: error (device md127) in __btrfs_free_extent:6314: errno=-2 No such entry
2016-07-11 19:06:19: BTRFS critical (device md127): corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2016-07-11 19:02:56: readynasd[16784]: segfault at 29 ip 00007fe64ad78a17 sp 00007fe630ff8600 error 4 in libnml.so.0[7fe64ad66000+1a000]
2016-07-11 16:07:10: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-22 09:11:41: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-22 09:11:14: Stack:
2015-10-21 11:15:59: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-21 11:15:32: md/raid:md127: raid level 5 active with 5 out of 6 devices, algorithm 2
2015-10-21 09:47:17: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-21 09:46:49: md/raid:md127: raid level 5 active with 5 out of 6 devices, algorithm 2
2015-10-21 09:46:48: md/raid:md1: raid level 6 active with 5 out of 6 devices, algorithm 2
2015-10-21 09:32:26: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-21 08:26:19: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-21 07:56:08: btrfs: corrupt leaf, bad key order: block=6551450771456,root=1, slot=1
2015-10-15 13:32:55: BUG: unable to handle kernel paging request 

I need desperately to recover all the data

please help me