[LU-13045] WBC2: batch metadata update

Related — Mon, 13 Feb 2023 09:54:18 +0000

During flush under WBC, a client could send a batch of metadata updates to MDT to improve the metadata performance a lot.

For batch metadata updates, the following points need to consider:

If batch metadata updates need to return with locks (in case of WBC EX lock revocation), it needs to grant a batch of locks to the client and the client needs to cache the returned batch of locks on its DLM lock namespace.
Transaction:
Recovery: VBR
Dependency:
- The client must ensure the dependencies in batching metadata updates must be ordered.
- Each metadata update action in batching metadata update request should be executed one by one in a single thread on MDT;
- If want to improve the performance of batching metadata update request by executing metadata updates in parallel in multiple threads, the MDT must carefully handle the dependencies.
- When DNE involves, the client also needs to consider the dependencies among MDTs when do a batching metadata updates which is same as boosting batching metadata updates using multiple threads..

Whamcloud Community JIRA