Ceph » CephFS

Creating a separate ticket to distinguish this from the #10649 code.

This was a pre-existing issue, but it's going to be more noticeable with the OMAP code: there was nothing to save the sessionmap as a result of updates to completed_requests (either add_completed_request or trim_completed_requests) calls.

The example of where this matters (from zheng) is:

I think we need to save completed_requests for corner cases. consider following scenario:

Client A sends setattr request to MDS
MDS handles the request and sends reply to client. But network between MDS and client A becomes disconnected.
MDS handles lots of setattr requests from other clients. Log entry for the first setattr request get trimmed
MDS crashed, standby MDS on other host takes over.
Client A re-send the setattr request to the new MDS.