LUKS Boot error: can’t read superblock

[f_lux]

Hi Community!

I’m suffering with an “Can’t read superblock” issue after logging in with GRUB with my luks-encrypted HDD. It happens after a power failure.

I can decrypt the luks-Partition from a USB-Linux:

sudo cryptsetup open /dev/sda1 crypto

runs well.

But after that I’m stuck.

sudo mount /dev/mapper/crypto /mnt

Says “Bad Superblock”.

I’m not really a Linux-Expert so I’m thankfull for any advice to make my system boot again. (Or even get access to the partition to save the latest data ;o)

Thanks in advance!

[megavolt]

Hello @f_lux

If it is ext4, then the first superblock is corrupt. You need to check the file system with another suberblock:

Can’t start session after battery drain off

Hello @onzo It seems the file system is damaged and therefore it can’t read the superblock. So the normal repair at boot did not work. You will need boot a manjaro boot disk and repair it: list all backup superblocks: dumpe2fs -h /dev/sda5 and then sudo fsck -b <superblock> /dev/sda5 like this: sudo fsck -b 32768 -y /dev/sda5 You will need to test every superblock until it works. If it worked, it is also useful to detect badblocks and tell ext4 to skip them: sudo fsck -vcck /de…

Instead of /dev/sda5 use /dev/mapper/crypto.

[f_lux]

Hey Megavolt!

Thx 4 your quick reply!

This is the output of

dumpe2fs -h /dev/mapper/crypto

Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          074ae4c1-cb01-4238-8cc7-8c57327bbac8
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
Filesystem flags:         signed_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              60473344
Block count:              241882372
Reserved block count:     12094118
Overhead clusters:        4078171
Free blocks:              187419531
Free inodes:              59904692
First block:              0
Block size:               4096
Fragment size:            4096
Group descriptor size:    64
Reserved GDT blocks:      1024
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Sun Apr 18 15:25:17 2021
Last mount time:          Tue Aug 31 13:51:27 2021
Last write time:          Tue Aug 31 13:51:27 2021
Mount count:              261
Maximum mount count:      -1
Last checked:             Mon Apr 26 07:28:57 2021
Check interval:           0 (<none>)
Lifetime writes:          689 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     32
Desired extra isize:      32
Journal inode:            8
First orphan inode:       45619293
Default directory hash:   half_md4
Directory Hash Seed:      f0d71e13-c039-43c1-8ed7-4b85e3394fdb
Journal backup:           inode blocks
Checksum type:            crc32c
Checksum:                 0xd1d59abb
Journal features:         journal_incompat_revoke journal_64bit journal_checksum_v3
Total journal size:       1024M
Total journal blocks:     262144
Max transaction length:   262144
Fast commit length:       0
Journal sequence:         0x000aa0ad
Journal start:            1
Journal checksum type:    crc32c
Journal checksum:         0x04a61eb9

Which entrys are the “superblock”-backups I have to use?

[f_lux]

@f_lux

superblock

An well, yes, its ext4

[megavolt]

Seems there changed something in the code or I made a mistake there… However, this should display it:

LANG=C sudo dumpe2fs /dev/mapper/crypto | grep -i superblock

[f_lux]

This is my

sudo dumpe2fs /dev/mapper/crypto | grep -i superblock

Output:

Illegal block number passed to ext2fs_mark_block_bitmap #5226077461718260773 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #13651645614301301791 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #12595942493672616290 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #14645335420504974825 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #10072002517370665981 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #1752149066609342841 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #7190106265735448415 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #7873875386962603264 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #3403445120102809709 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #14043753746309486185 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #14649079976496093918 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #690396004654180565 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #5783314249158287372 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #13559547385824256304 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #1813511074410412626 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #720335521950401567 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #6669190058244424297 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #7105116799863360566 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #5192936692069940048 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #8349572122462118418 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #11538410855975775488 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #5030694150573982560 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #5468374690071020471 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #12967513178455050479 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #4725089721210717993 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #5210536449567075156 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #18239724053703962131 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #4521208374437781480 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #1563680391884738378 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #10135875637113008983 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #445607863422464378 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #16608474675953798019 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #9310491083921194983 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #11449932432613944592 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #4921970503471470787 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #13660515395626356667 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #2428183638273429182 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #12108474408317219737 for block bitmap for /dev/mapper/crypto
Illegal block number passed to ext2fs_mark_block_bitmap #1439035655824226557 for block bitmap for /dev/mapper/crypto
  Primary superblock at 0, Group descriptors at 1-116
  Backup superblock at 32768, Group descriptors at 32769-32884
  Backup superblock at 98304, Group descriptors at 98305-98420
  Backup superblock at 163840, Group descriptors at 163841-163956
  Backup superblock at 229376, Group descriptors at 229377-229492
  Backup superblock at 294912, Group descriptors at 294913-295028
  Backup superblock at 819200, Group descriptors at 819201-819316
  Backup superblock at 884736, Group descriptors at 884737-884852
  Backup superblock at 1605632, Group descriptors at 1605633-1605748
  Backup superblock at 2654208, Group descriptors at 2654209-2654324
  Backup superblock at 4096000, Group descriptors at 4096001-4096116
  Backup superblock at 7962624, Group descriptors at 7962625-7962740
  Backup superblock at 11239424, Group descriptors at 11239425-11239540
  Backup superblock at 20480000, Group descriptors at 20480001-20480116
  Backup superblock at 23887872, Group descriptors at 23887873-23887988
  Backup superblock at 71663616, Group descriptors at 71663617-71663732
  Backup superblock at 78675968, Group descriptors at 78675969-78676084
  Backup superblock at 102400000, Group descriptors at 102400001-102400116
  Backup superblock at 214990848, Group descriptors at 214990849-214990964
dumpe2fs: Block bitmap checksum does not match bitmap while trying to read '/dev/mapper/crypto' bitmaps

I start with the 1rst Superblock (Primary?):

sudo fsck -b 0 /dev/mapper/crypto

Output:

2fsck 1.46.2 (28-Feb-2021)
/dev/mapper/crypto: recovering journal
fsck.ext4: Input/output error while trying to re-open /dev/mapper/crypto
/dev/mapper/crypto: ********** WARNING: Filesystem still has errors **********

And then I stuck on the second Superblock:

sudo fsck -b  32768 /dev/mapper/crypto

Output:

e2fsck 1.46.2 (28-Feb-2021)
fsck.ext2: Input/output error while trying to open /dev/mapper/crypto
The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.  If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
 or
    e2fsck -b 32768 <device>

[f_lux]

It’s for sure ext4 and I do have only one partition for the whole system. So: no swap & no ufs…

[megavolt]

Try every superblock, until it works. If non works, then the data is bascally gone. At least it would be really difficult to rescue any data…

[megavolt]

When pasting terminal output, add three backticks ` OR 3 tilde ~ above and below the text:

text

I did it this time for you. Please do it like this in the future.

Thank you

[megavolt]

@f_lux

fsck.ext2: Input/output error while trying to open /dev/mapper/crypto

Maybe try it with

sudo fsck.ext4 -b  32768 /dev/mapper/crypto

No idea why there is a I/O Error… Is the drive defect? If so, then I would rather suggest, to create an image of the partition.

sudo dd if=/dev/sda1 of=/path/to/sda1.img conv=sync,noerror bs=64K 

[winnie]

@f_lux

sudo fsck -b 32768 /dev/mapper/crypto

@f_lux

fsck.ext2: Input/output error while trying to open /dev/mapper/crypto
The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.

It’s not looking good.

You can also try to add the block size (-B 4096), force (-f), and verbose (-v) options while you’re at it. Looks like your ext4 filesystem is using 4K block size.

sudo fsck.ext4 -v -f -b 32768 -B 4096 /dev/mapper/crypto

---

What is the health of this disk? Is it an external HDD? Did you run a short and/or extended SMART test on it?

[f_lux]

Hi folks!

Maybe I’m truly facing a hardware failure.

It’s a internal Samsung 860 EVO 1TB SSD, bought in April 2021. So it’s a very new piece of hardware.

Anyway. My output of

smartctl

is nothing good:

Short INQUIRY response, skip product id

Output of

sudo dd if=/dev/sda1 of=/path/to/sda1.img conv=sync,noerror bs=64K

says

dd: error reading '/dev/sda1': Input/output error

So, I guess the sdd is gone?

[megavolt]

@f_lux

So, I guess the sdd is gone?

Sadly saying: Unfortunately yes. I hope you have a backup

[winnie]

Another victim of an electrical outage / power loss?

I guess this is as good a time as any to vouch for a UPS battery backup for any desktop / server computer.

---

But to better understand, you can’t even successfully dd from the SSD, even in a live session using sudo? What about if you make the output null? (i.e, of=/dev/null)?

[f_lux]

Hey there!

sudo fsck.ext4 -v -f -b 32768 -B 4096 /dev/mapper/crypto

did it!

It’s probably adding the blocksize…?! Dunno.

After that process I was able to chroot into the system and rewrite grub.

Thank you so much folks, for your support!