XFS_IOC_SWAPEXT failed... Invalid argument

$ lsb_release -rd
Description: Ubuntu 8.04.2
Release: 8.04

$ uname -r
2.6.24-23-generic

$ apt-cache policy xfsdump
xfsdump:
  Installed: 2.2.45-1
  Candidate: 2.2.45-1
  Version table:
 *** 2.2.45-1 0
        500 http://us.archive.ubuntu.com hardy/main Packages
        100 /var/lib/dpkg/status

xfs_fsr -v doesn't seem to work anymore, I get a bunch of messages like this:

XFS_IOC_SWAPEXT failed: ino=6327324: Invalid argument
ino=52300
XFS_IOC_SWAPEXT failed: ino=52300: Invalid argument
ino=52295
XFS_IOC_SWAPEXT failed: ino=52295: Invalid argument
ino=52299

And, after it's done, the fragmentation stays roughly the same:
before: actual 4464, ideal 230, fragmentation factor 94.85%
after: actual 4799, ideal 289, fragmentation factor 93.98%

The filesystem is 26% full (and recently experienced numerous deletions of very large files).

I found this bug (and a fix) in the kernel bugzilla, but the kernel version is more recent... perhaps something was backported to Ubuntu's hardy kernel?
http://bugzilla.kernel.org/show_bug.cgi?id=12538