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I restarted my laptop because I installed (already) an update. But after a bit, nothing was on the screen. Only a dark violet background. So, after 5 minutes, I kept pressed the power button and my laptop shut down. When I booted it back, the laptop showed somthing. I think that the most important thing is:

/dev/mapper/ubuntu--vg-root contains a file system with errors, check forced. /dev/mapper/ubuntu--vg-root: Inodes that were part of a corrupted orphan linked list found. /dev/mapper/ubuntu--vg-root: UNEXPECTED INCOSISTENCY; RUN fsck MANUALLY. fsck exited with status code 4. The root filesystem on /dev/dm-0 requires a manual fsck.

But fsck doesn't work. I also attached a photo. I wouldn't like to reinstall Ubuntu, because I have lots of important stuff. I have another (Windows) laptop, which now I use. What should I do? The error

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Yup. It looks like you have a bad superblock. First I'll tell you the cause of the problem, and then give you the solution. : )

The cause:

Ok. So when Ubuntu boots, it goes through 4 stages:

  • BIOS

  • Bootloader

  • Kernel

  • System Startup

BIOS

When your computer goes through BIOS, it executes the firmware code, which tells the important components like the CPU, RAM, Display and others: "Hey guys! Wake up, its time to work!" So once everyone wakes up, the computer moves on to the next stage:

Bootloader

When you see that purple screen that says something like "GRUB", then that's GRUB, the bootloader. It lets you choose which operating system you want to boot, advanced options for them, and other things like opening a command line. Once you have chosen an OS to boot, it moves on to the next stage:

Kernel

The kernel stage is probably the most important of all because that's when the system mounts the hard drive, reads the important files on it, and actually 'put together' the computer. That's where you're having your problem. The system was most likely trying to mount the hard drive when you force closed it. It stuck midway through, and even though it reset, the drive still has an error. The superblock was damaged.

Solution:

Step 1:

Get the DVD that you installed Ubuntu from, boot into it, and choose the 'Try Ubuntu without installing' option when it shows its temporary 'bootloader'.

Step 2:

Once it loads, open a terminal by pressing Ctrl + Alt + T

Step 3:

Execute this:

sudo fdisk -l

That will list all disk partitions. Now, you can find the partition your broken boot is on. Usually, the partition that holds your main OS is usually the one marked as bootable. This is the output of mine, as an example:

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048   637770013   318883983   83  Linux
/dev/sda2       637771774  1953523711   657875969    5  Extended
Partition 2 does not start on physical sector boundary.
/dev/sda5      1945303040  1953523711     4110336   82  Linux swap / Solaris
/dev/sda6       637771776  1945303039   653765632   83  Linux

The bootable partition is marked with a *. That is most likely the broken one.

Step 4.

Execute this command:

sudo dumpe2fs /dev/(sda the live cd is on*) | grep superblock
  • if your linux is a dual-booted one, list the partition that the broken boot is on

It will list all backup superblocks to fix the broken superblock. Output:

  Primary superblock at 0, Group descriptors at 1-20
  Backup superblock at 32768, Group descriptors at 32769-32788
  Backup superblock at 98304, Group descriptors at 98305-98324
  Backup superblock at 163840, Group descriptors at 163841-163860
  Backup superblock at 229376, Group descriptors at 229377-229396
  Backup superblock at 294912, Group descriptors at 294913-294932
  Backup superblock at 819200, Group descriptors at 819201-819220
  Backup superblock at 884736, Group descriptors at 884737-884756
  Backup superblock at 1605632, Group descriptors at 1605633-1605652
  Backup superblock at 2654208, Group descriptors at 2654209-2654228
  Backup superblock at 4096000, Group descriptors at 4096001-4096020
  Backup superblock at 7962624, Group descriptors at 7962625-7962644
  Backup superblock at 11239424, Group descriptors at 11239425-11239444
  Backup superblock at 20480000, Group descriptors at 20480001-20480020
  Backup superblock at 23887872, Group descriptors at 23887873-23887892
  Backup superblock at 71663616, Group descriptors at 71663617-71663636
  Backup superblock at 78675968, Group descriptors at 78675969-78675988

Step 5.

Use this command to choose a backup superblock to fix the broken one:

sudo fsck -b (**superblock** that you chose) /dev/(sda the live cd is on) -y

Remember, you can choose any superblock, as long as it says it's a backup one. And, by the way, the -y at the end is to answer all the Fix? questions. Trust me. There are a lot of them.

So, once you run it, it gets really cool, or creepy, (it's cool to me XD) because it will start to imitate a TV that is on a static channel. That was really funny when i first saw it! Take a video recording and turn it into a GIF if you like. (i might attach one one time ; )

So! Enough talking while we wait! Once that's done, move on to the next step:

Step 6.

Mount the drive:

sudo mount /dev/(sda that cd is on) /mnt

So you can test the filesystem.

Step 6.

6A.

Login to root:

su

6B.

Run command:

cd /mnt

6C

Run command:

mkdir fixtest

6D

Run command:

rm fixtest

If you're able to do all these commands without errors, then you're all set! Restart your computer the normal way, and enjoy!

Hope this works! ; )

  • Ooh! Happy it worked for you! ; D – Skybbles Mar 23 '16 at 13:00

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