xfsdump does not work since 2.6.35 and producing following output: http://www.spinics.net/lists/xfs/msg00910.html It reports warnings "Invalid argument: using null generation count in directory entry" and NOT dumping reported files. The patch (http://www.spinics.net/lists/xfs/msg00924.html ) fixes the problem. After applying xfsdump works correctly.
Created attachment 248099 [details, diff] Patch from http://www.spinics.net/lists/xfs/msg00924.html
It seems that gentoo-sources-2.6.35-r8 based on 2.6.35.5 have this bug fixed.