27

I have a Debian system here. fsck runs from time to time while booting (on an ext4 file system).

I get messages like this:

inode extent tree (at level 1) could be shorter IGNORED

What do they mean?

Stephen Kitt
  • 411,918
  • 54
  • 1,065
  • 1,164
buhtz
  • 777
  • 1
  • 10
  • 22

1 Answers1

31

They mean that e2fsck determined that an extent tree (a data structure used to point to data in the file system) could be restructured to have less depth (presumably because it tracked extents in the past which are no longer in use, so the tree could be rebalanced). That’s not much of a problem in practice, unless the extent depth is greater than the maximum; so it can be ignored, as you’re seeing. If an extent tree is too big, e2fsck will force a rebuild and you won’t see the IGNORED message.

If you run e2fsck interactively, it will ask you whether it should fix these trees, instead of just ignoring them.

Stephen Kitt
  • 411,918
  • 54
  • 1,065
  • 1,164
  • 1
    And should one fix them? And is this just something that happens from time to time or is it an indicator of impending hdd failure, or something? – pbhj Jun 16 '20 at 16:23
  • 5
    As mentioned in the answer, when they need to be fixed, `fsck` will fix them instead of ignoring them. This happens from time to time, it’s not corruption, and it doesn’t indicate an impending failure. – Stephen Kitt Jun 16 '20 at 16:26
  • 1
    I can confirm that if you run e2fsck -f /dev/sda1 it will ask if it should fix ignored too. And will fix them. – Валерий Заподовников Jun 05 '23 at 04:34