HttpUploadModule - after upload file won't move/rename

I'm trying to setup a very simple HTTP POST file upload server. I'm trying to POST files via curl, without worrying about forms or responses, etc. I just want to drop the file in nginx, and have it land.

So far, the file uploads into the upload_store location, but it doesn't move out. I'm left with a valid file with a hashed filename, in a hashed directory. I feel like I'm missing something simple and obvious, and have got a bit crosseyed in the process. Here's my config:

location /data {
upload_pass /returnok;
root /opt/datapush/test;
upload_store /tmp/upload 1;
upload_store_access user:rw group:rw all:rw;
upload_set_form_field $upload_field_name.name "$upload_file_name";
upload_set_form_field $upload_field_name.content_type "$upload_content_type";
upload_set_form_field $upload_field_name.path "$upload_tmp_path";

upload_cleanup 400 404 499 500-505;


access_log /mnt/log/nginx/datapush_access.log main;
error_log /mnt/log/nginx/datapush_error.log debug;
}
location /returnok {
return 200;
}

/opt/datapush/test/data exists, and is 777 (got a little frustrated at one point). Also, i have debug logging turned on, and everything looks good, but there is no mention of it trying to rename or move the file, and no error to that effect either. Come on, someone show me what I'm over looking here.