How to update all when you need callbacks fired?

Let's say I've got 15 user ids in an array called user_ids.

If I want to, say, change all of their names to "Bob" I could do:

users = User.find(user_ids)
users.update_all( :name => 'Bob' )

This doesn't trigger callbacks, though. If I need to trigger callbacks on these records saving, to my knowledge the only way is to use:

users = User.find(user_ids)
users.each do |u|
  u.name = 'Bob'
  u.save
end

This potentially means a very long running task in a controller action, however.

So, my question is, is there any other better / higher performance / railsier way to trigger a batch update to a set of records that does trigger the callbacks on the records?