是的，回调都是在一个事务包裹起来。

Yes, the callbacks are all wrapped up in a transaction.

基本上，以下将导致回退：

Basically, the following will cause a rollback:

• 从 before_save 返回false或类似的回调
• 异常 before_save 或类似的回调
• 异常 after_save的或类似的回调（after_create）

• return false from before_save or similar callbacks
• exception in before_save or similar callbacks
• exception in after_save or similar callbacks (after_create)

下面不会导致回滚：

• 从 after_save的返回false或类似的回调
• 异常 after_commit

• return false from after_save or similar callbacks
• exception in after_commit

如果你不想异常引起回滚，使用 after_commit

If you don't want an exception to cause a rollback, use after_commit

• 参考：http://webonrails.com/2012/08/28/activerecord-after_commit-hook/
• 附加参考：http://guides.rubyonrails.org/v3.1.3/active_record_validations_callbacks.html#transaction-callbacks

• Reference: http://webonrails.com/2012/08/28/activerecord-after_commit-hook/
• Additional reference: http://guides.rubyonrails.org/v3.1.3/active_record_validations_callbacks.html#transaction-callbacks