Expand description
2026-09-25: The Linux file backend: io_uring fixed-buffer reads (SQPOLL,
registered pinned buffers) into qd bounce buffers, each copied to the
device on the caller’s stream.
Owner: metrale-storage high-speed swap. Invariants:
- A bounce buffer is refilled only after the event recorded behind its last
host-to-device copy has completed (
wait_buffer_free).