Comment 6 for bug 132762

I'm not sure what you mean by "compatibility problems with the upcoming ext4 filesystem". You will get better performance if you remake the filesystem as ext4 from the beginning as opposed to converting an existing ext3 filesystem to ext4, but the latter certainly works. Also, note that that use of a 256-byte inode is not ext4-specific. It's something we started doing in ext3 since it makes a huge difference if your system is using lots of extended attributes, as the Beagle search program and SELinux tends to do. Ext3 has supported storing xattrs in large inodes for quite some time. Unfortunately grub doesn't know how to deal with 256-byte inodes unless it is patched to do so. Ext4's sub-second timestamps and some other features also require 256-byte inode, but ext4 (although with fewer features) on a legacy filesystem with 128-byte inodes.