Yes, but I suspect there might be some confusion by the author and others between "io_uring completion of a write" (ie: io_uring sends its completion queue event that corresponds to a previous submission queue event) and "fsync completion" (as you've put as "completion of all writes", though note that fsync the api is fd scoped and the io_uring operation for fsync has file range support).
The CQEs on a write indicate something different compared to the CQE of an fsync operation on that same range.
