On 6:52 05/12, Christoph Hellwig wrote: > If you want to export these at all they have to be EXPORT_SYMBOL_GPL. > Understood. > But I'd really like to avoid seeing another duplicate DAX I/O path. > Please try to adopt the existing iomap-based infrastructure for your > needs first. This is not worth with btrfs. With non-page aligned I/O on btrfs, we need to copy the first/last page of the extents for CoW. So, we would end up using the exported functions anyways. Believe me, I have spent some time getting btrfs iomap compatible before giving up. The problems are btrfs needs to carry a lot of information across iomap_begin and iomap_end. While the added private variable helps in this, it also needs hooks in bio_submit() functions for crc calculations during direct writes. -- Goldwyn
