Always carry a puncture repair kit for stuff like this, as if the nail comes out you're likley to loose a lot of air fairly quickley. As long as the hole is in the centre 70% or so of the tread (as in not right up by the side wall) you should be fine to have it patched properly. They should take the tyre off and insert a plug from the other side, at which point it's as good as new IMO
