Block user writes is a feature that prevents any writes to a cluster. This feature was initially designed for use by mongosync in a C2C deployment, but it is available to users for any purpose they see fit.

Currently, we have a "proxy" that accepts some reserved namespaces to bypass the UserWriteBlockMode. However, we need to find a more general solution. We must ensure that internal operations are permitted to write or execute DDLs regardless of the UserWriteBlockMode value.

Furthermore, it would be beneficial to include a new suite that runs existing tests with user writes blocked.