When rsync 2.6.9 is patched with the patch: rsync-2.6.9/patches/source-filter_dest-filter.diff
You get this:
rsync: read errors mapping "<some file>": No data available (61)
By re-ordering some code in the patch, this can be made to function correctly. I have a patch here to fix this: http://projects.nickblundell.org.uk/sites/projects.nickblundell.org.uk/files/blundell_rsync2.6.9_source_dest_filter.patch
I have made the analogous change to the patch in CVS.
Thanks for your help.
A note for future patches:
An easier way to show what changed in a patch is to produce a diff that can be applied to the code after the released diff. E.g. patch your rsync-2.6.9-orig code with the patch before you diff against the fixed code. FYI.