Thanks for your review! I don't know kfs, but I think there's some confusion because Hadoop's kfs-0.2.2 uses org.kosmix as the groupId while kfs-0.3 uses net.sf.kosmosfs as the groupId. It's the same package though, in Java they both use the org.kosmix package name space. It's commented in the ivy config because kfs-0.2.2 and older aren't available through Maven central. This is why the lib is checked into svn.
The problem with my patch is that we can't downgrade to kfs-0.2.2 without causing problems for Maven users. There are three options: 1) leave it at 0.3, 2) deploy kfs 0.2.2 to Maven central, or 3) upgrade Hadoop to use kfs-0.3. Option 3 sounds like the best but I have no way of testing this (there's no test case and wiki documentation seems to have moved on to Hadoop 2). It compiles with some warnings, but whether it actually works is a different question.