Neither rustfs/src/storage/backpressure.rs nor rustfs/src/storage/lock_optimizer.rs had a production caller: their only non-self references were the pub mod lines in storage/mod.rs and a cfg(test) module, so the object transfer path never applied this backpressure and never took these lock shortcuts.
The six removed tests in concurrent_fix_test.rs duplicated tests that lived inside the deleted files; the shared primitives they shadowed keep their own coverage in rustfs-io-core.
