[Virtio-fs] data integrity in dax mode

[Liu Bo]

Hi,

I have a concern about data integrity in dax mode.

For now virtio_fs_copy_from_iter() (i.e. the write direction) only
does copy_from_iter(), which doesn't enforce a clean_cache_range or
CLWB.  And even worse, virtio-fs doesn't have a dax_writepages like,
which can calls dax_writeback_mapping_range().

Correct me if I'm wrong, but did virtio-fs solve it in some way?

thanks,
-liubo