[parted-devel] [PATCH] Detect Ext4 (Parted Alioth #188)

[Colin Watson]

On Fri, Jan 09, 2009 at 03:28:14PM +0100, Jim Meyering wrote:
> "Bryn M. Reeves" <bmr at redhat.com> wrote:
> > Colin Watson wrote:
> >> And of course it turns out to be rather hard to test these, because
> >> ext3's maximum file size is 2TB and we need 2^32 4KB blocks (i.e. 16TB)
> >> before needing to use the high longword of the block count, so it's
> >> rather hard to create this situation with the sparse loopback file
> >> approach that would work reasonably in parted's test suite. I can't even
> >> create an ext4 filesystem and put a loopback file in that (not that that
> >> would be viable in parted's test suite) because ext4's maximum file size
> >> is 16TB. Any ideas?
> >
> > How about using a sparse block device instead of a loopback device
> > backed by a sparse file?
> 
> Or use a file on an xfs file system as the backing store.
> Here's a 9MB file with apparent size of over 5 exabytes:

Unfortunately this didn't work for me, perhaps because I'm running a
32-bit kernel.

I tried the script Bryn linked to (thanks!) and got as far as mkfs.ext4
with that, but the e2fsprogs I currently have doesn't support actually
creating large ext4 filesystems yet; so I think this will have to remain
untested for now, unless any ext4 hackers on the list can give it a try.

Thanks,

-- 
Colin Watson                                       [cjwatson at ubuntu.com]