- *
- * LINUX_FADV_ASYNC_WRITE: start async writeout of any dirty pages between file
- * offsets `offset' and `offset+len' inclusive. Any pages which are currently
- * under writeout are skipped, whether or not they are dirty.
- *
- * LINUX_FADV_WRITE_WAIT: wait upon writeout of any dirty pages between file
- * offsets `offset' and `offset+len'.
- *
- * By combining these two operations the application may do several things:
- *
- * LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
- *
- * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE: push all of the currently
- * dirty pages at the disk.
- *
- * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE, LINUX_FADV_WRITE_WAIT: push
- * all of the currently dirty pages at the disk, wait until they have been
- * written.
- *
- * It should be noted that none of these operations write out the file's
- * metadata. So unless the application is strictly performing overwrites of
- * already-instantiated disk blocks, there are no guarantees here that the data
- * will be available after a crash.