It's all in the bag. The best footballer that is and will be has signed on for Barca till 2018 when he turns the ripe old age of 31 years. It was a two year extension on his contract that was due to run out in 2016.
Note to Arsene Wenger and Arsenal, this is how you negotiate. Well in advance. For the players you should want to keep. Plus, as is rote in the Liga, Messi has a release clause, except its worth €250 million/ $335 million/ £213 million. To keep in perspective, that is about one ninth the valuation of Man Utd, the most expensive sports franchise in the world, at €2.24 billion/ $3 billion/£1.91 billion.
Note to Arsene Wenger and Arsenal, we don't want Messi because then you'll charge us £500 per match and £25 for a soggy meat pie in the extra-terrestrial event he wants to come. We want Ybingewe Kidolalelee Shingbatwoano, if he can hold midfield.