ext3 converted to ext4 still being mounted as ext3

morgon asked:

I have a somewhat bizzare problem at the moment with my Debian-system (mainly testing).

I used to have a root-partition on lvm that was formatted as ext3.

I now booted a live-system and converted the ext3 into ext4 (via tune2fs…) and also did a fsck.ext4. In the live-system I can mount the partition as ext4.

Then I changed the entry in /etc/fstab from ext3 to ext4 and rebooted my Debian.

The problem is that the partition (even though it says ext4 in /etc/fstab) seems still be to mounted as ext3 – at least that is what mount says.

When I try to determine the filesystem-type I get inconsistent results:

fsck -N reports ext4:

sudo fsck -N /dev/mapper/hed-root 
fsck from util-linux 2.20.1
[/sbin/fsck.ext4 (1) -- /] fsck.ext4 /dev/mapper/hed-root 

but blkid says ext3

sudo blkid -o value -s TYPE /dev/mapper/hed-root 

As I said the filesystem resides in a lvm-volume. I changed nothing there.

What can I do to resolve this?

Many thanks!

My answer:

Based on your filesystem features output, you didn’t actually convert your filesystem to ext4.

To resolve the issue, convert the filesystem to ext4. Reboot your live CD and run the appropriate commands:

tune2fs -O extents,uninit_bg,dir_index /dev/mapper/hed-root
e2fsck -fDC0 /dev/mapper/hed-root

(Note that the ext4 driver is capable of mounting ext2 and ext3 filesystems, which is why your system is currently usable.)

View the full question and answer on Server Fault.

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.