Do any of the disks report sector errors or ATA or read errors?
smartctl -a /dev/sdx should give the report, assuming you run smartd
and have it probe disks periodically.

	No, they are clean.

I've seen newer versions of the xfsprogs and libs packages. Try using
those. I know you're against new packages that haven't been included
in "stable" -- but if this is a dev/backup system, it's worth the shot
in my opinion.

	Well, either way, that's not going to help in this situation.
Either there is something I can attempt to fix in the underlying array
structure, or else I am going to have to erase the log and continue.

	I'm not sure what you mean by dev/backup.  The file system is not
created as a device on any other system by udev, if that's what you mean.
It's just a Linux system dedicated solely to running rscync backups every
morning at 04:00.  The array does get mounted on other systems using SAMBA
or NFS, as the case may be, so I can easily copy over files to the main
systems lost or corrupted through whatever means.