Refactor rtree_leaf_elm_extent_write() as rtree_leaf_elm_extent_lock_write(), so that whether the leaf element is currently acquired is separate from what lock state to write. This allows for a relaxed atomic read when releasing the lock.
Refactor rtree_leaf_elm_extent_write() as rtree_leaf_elm_extent_lock_write(), so that whether the leaf element is currently acquired is separate from what lock state to write. This allows for a relaxed atomic read when releasing the lock.