Mostly just a quick note to myself.

As noted elsewhere on the web, there is some problems with Rack and file uploads when using Ruby 1.9.

The problem has been fixed in Rack, but Passenger bundles their own Rack, which makes it a bit tricky until they release a newer version.

So I went into /usr/lib/ruby19/gems/1.9.1/gems/passenger-2.2.2/vendor and removed rack-1.0.0-git, replacing it with a fresh checkout from GitHub.

One /etc/init.d/apache restart later, and all is good.