title: If a multi update fails partially in mongodb, how to roll back?
body: <p>I understand that a multi update will not be atomic and there are chances that the update query may fail during the process. The error can be found via <code>getLastError</code>. But what if I want to roll back the updates that have already been done in that particular query? Any method simpler than the tedious two phase commits?</p>
  
  <p>For instance, let me say I have a simple collection of some users and their phone models. Now I do a multi update on all the users who have a Nexus 4 to Nexus 5 (Dreamy, isn't it?). The only condition being, all or none - so all the N5s are taken back if even one N4 user doesn't get his. Now, somehow the mongodb fails in between, and I am stuck with a few users with N4 and a few with N5. Now, as I have gathered from the net is that I can't have mongo roll back directly. If the operation failed, I will have to do a manual update of the N5 users back to N4. And if that fails too somehow, keep repeating it.
  Or when I have a complicated collection, I will have to keep a new key viz. <code>Status</code> and update it with keywords <strong>updating</strong>/ <strong>updated</strong>.</p>
  
  <p>This is what I understand. I wanted to know if there is any simpler way. I assume from the comments the answer is a big no.</p>