Hi all, We are working on RBD persistent writeback cache which caches data on block devices. Currently, we operate the cache device using the driver in BlueStore: src/os/bluestore/KernelDevice. Meanwhile, we may need to use other block device drivers in BlueStore. So we need to reuse these codes in librbd. Thanks to Jason who gave us some suggestions. And Changcheng submitted a PR about this work. https://github.com/ceph/ceph/pull/34622/ Welcome for more suggestions and comments. Best wishes Lisa -- Best wishes Lisa