I have a couple of filesystems that where initially created as ext3 and later converted to ext4 (tune2fs -O extents,uninit_bg,dir_index ...; fsck.ext4 -pfD ...); I mount then as ext4, have been using them for some time, and everything seems fine.

However, "fsck -N" still reports them as ext3, not ext4. This would be just a cosmetic issue, were not for some programs (Fedora's rescue or upgrade, for example), that refuse to mount them, because they do not match what fstab says.

So, my question is, how does fsck detect them as ext3, and how can I change that info (other than mkfs, of course)? Many thanks!

Does fsck even know what ext4 is? Chances are that this version did'nt "know" ext4 at creation time...
Just a flake of a thought...by the way, what's the OS over there?

Thor

Strictly speaking, you still have an ext3 filesystem - with some extra functionality enabled, on files created since the tune2fs was run. Older files are still "bare" ext3 format.
You might be up for a mkfs after all I'd reckon.
Ted Ts'o maintains the ext? filesystems and tools. Current versions all know about all variants.

I'm currently using Fedora 16, and I can run ext4-related utilities (mkfs, fsck, mount, ...) without issues; but these fs where created many versions ago, well before ext4 existed. I hoped that I could make a full conversion from ext3 to ext4; but it looks like I'll have to create new filesystems after all. Many thanks.