Darren Bent insisted he had to leave Aston Villa after too many "slaps in the face".
Brighton defender Greg Halford has agreed to extend his loan deal from Nottingham Forest until the New Year.
The 18-year-old full-back, a product of Rovers' academy, will remain at Ewood Park until June 2017, with the option of a further year.
"It is fantastic, it is something I've been working towards for a long time now and it feels great to get it done," Henley told the club's official website
"I really enjoy it here, I always have, I've been here since I was nine or 10 and I've enjoyed every minute of it. It feels great to secure my time here."
Henley made his first-team debut as a second-half substitute away to Wigan
last November, and his full Premier League debut came just a month later in the Boxing Day draw at Liverpool.