[!] Unable to mount nilfs2 filesystem after power outage - error loading super root.

[KARBOWSKI Piotr <piotr.karbowski-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hi,

Yesterday I had an power outage. After booting my notebook again, I was 
no longer able to mount /home that was on the top of nilfs2 filesystem.

I've come across a post from 2011 about fsck in git.nilfs.org but that 
repo is no longer accessable. The repo from githab does not have any 
trace of the experimental fsck tool thus I've dumped the filesystem to 
image, recreated ext4 and restored backup.

The symptoms:

# mount -o loop ./kurogane_ssd-home.17.03.2016.img /mnt/tmp
mount.nilfs2: Error while mounting /dev/loop/0 on /mnt/tmp: No such file 
or directory

# dmesg
[ 9591.626210] NILFS warning: mounting unchecked fs
[ 9591.824166] NILFS: error loading super root.

No nilfs-utils's tools works beside the tune with -l

# nilfs-tune -l /dev/loop1
nilfs-tune 2.2.2
Filesystem volume name:	  home
Filesystem UUID:	  6a915104-61d5-4214-bed4-2538d1bdfaa5
Filesystem magic number:  0x3434
Filesystem revision #:	  2.0
Filesystem features:      (none)
Filesystem state:	  invalid or mounted
Filesystem OS type:	  Linux
Block size:		  4096
Filesystem created:	  Sat Nov 14 14:40:18 2015
Last mount time:	  Thu Mar 17 17:41:23 2016
Last write time:	  Thu Mar 17 22:46:08 2016
Mount count:		  154
Maximum mount count:	  50
Reserve blocks uid:	  0 (user root)
Reserve blocks gid:	  0 (group root)
First inode:		  11
Inode size:		  128
DAT entry size:		  32
Checkpoint size:	  192
Segment usage size:	  16
Number of segments:	  11294
Device size:		  94745133056
First data block:	  1
# of blocks per segment:  2048
Reserved segments %:	  5
Last checkpoint #:	  1016585
Last block address:	  17023836
Last sequence #:	  80736
Free blocks count:	  6764544
Commit interval:	  0
# of blks to create seg:  0
CRC seed:		  0x60cb4676
CRC check sum:		  0x68371ded
CRC check data size:	  0x00000118

This is something I woudn't expect from a log structured filesystem. I 
am running kernel 4.5.0.

Any comments and help with restoring access to this fs much appriecieate

-- Piotr.
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