Passing data from layout to block controller using setData

I'm trying to set a variable in my local.xml file for my custom block:

<layout>
    <!-- ... -->
    <page_homepage>
        <!-- ... -->
        <reference name="root">    
            <!-- ... -->
            <block type="core/template" name="home_page_sections" template="page/homepage/sections.phtml">
                <block type="layout/carousel" name="featured_carousel">
                    <action method="setData">
                        <name>filter_attribute</name>
                        <value>is_featured_product</value>
                    </action>
                </block>
            </block>
        </reference>
    </page_homepage>
</layout>

But I am not getting the data on the other end in my controller:

class Foo_Layout_Block_Carousel extends Mage_Core_Block_Template
{
    public function __construct() 
    {
        parent::__construct();

        $filterAttribute = $this->getFilterAttribute(); // Nothing
        $filterAttribute = $this->getData('filter_attribute'); // Nada

        // Alright, fine, what DO I have?!
        var_dump($this->getData()); // array(0) {} ... Argh!
    }
}

From all my searching I've found that this really should work, but since it does not, I have a feeling I'm missing something obvious. Here is my layout module's configuration (I'm using a single module to define a homepage and any other blocks I need for the site):

<?xml version="1.0"?>
<config>
    <modules>
        <Foo_Layout>
            <version>0.1.0</version>
        </Foo_Layout>
    </modules>
    <global>
        <page>
            <layouts>
                <foo_homepage translate="label">
                    <label>Homepage</label>
                    <template>