Logstash holding open deleted logs

Hi, we are using version 1.5.1-1 of logstash on centos 6 and logstash is holding open for days files that have been deleted by rotation. I've found a lot of discussion around this issue and logstash-forwarder, but nothing specific to logstash. Other than restarting logstash periodically, what is the best way to release these handles? Thanks.