I had 5.4 machine. Upgraded to 5.5 today via yum upgrade. All went fine. Rebooted. Wanted to convert root partition to ext4 (I have three partitions: /boot, / and swap). All of them on software RAID 1 (root is /dev/md2). I did the following for converting

```
yum install e4fsprogs
tune2fs -O extents,uninit_bg,dir_index /dev/md2
nano /etc/fstab # I indicated here that my /dev/md2 is of ext4
uname -a
mkinitrd -f /boot/initrd-2.6.18-194.3.1.el5.img 2.6.18-194.3.1.el5

```

Rebooted. I expected fsck to start automatically as said on some site. But it did not. Threw some error (don't remember exactly which). Ok, I booted linux rescue and executed fsck:

```
fsck -t ext4 -fy /dev/md2

```

Partition went fine. But still when I boot main system, it says in log: "ext3-fs:" then something about not being able to mount ext3 partition due to unknown extended attributed (200).

I booted linux rescue again. It loads fine and correctly determines all my machine partitions both ext3 (boot) and ext4 (/) under /mnt/sysimage just fine.

I retried mkinitrd thing again watching it's output and ensured ext4 module is included into the system. I also edited menu.lst grub file to include rootfstype=ext4 kernel parameter. Bad luck. I still have message from ext3-fs about not being able to mount filesystem because of attributes and kernel panic immediately after. I checked /etc/fstab - it's fine and saying that root is of ext4.

What did I do wrong? This machine is empty so I can just reformat it with 5.5 and recreate partitions to be originally ext4. But... I just want to know what did I do wrong.