[$] Asynchronous fsync()

The cost of fsync()
is well known to filesystem developers,
which is why there are efforts to provide
cheaper alternatives. Ric Wheeler wanted to discuss the longstanding idea of
adding an asynchronous version of fsync() in a filesystem session
at the 2019 Linux Storage, Filesystem, and Memory-Management Summit
(LSFMM). It
turns out that what he wants may already be available via the new io_uring interface.