On Wed, Mar 11, 2020 at 07:44:12AM +0100, Christoph Hellwig wrote: > On Wed, Mar 11, 2020 at 05:39:42PM +1100, Dave Chinner wrote: > > IOWs, the dax_associate_page() related functionality probably needs > > to be a filesystem callout - part of the aops vector, I think, so > > that device dax can still use it. That way XFS can go it's own way, > > while ext4 and device dax can continue to use the existing mechanism > > mechanisn that is currently implemented.... > > s/XFS/XFS with rmap/, as most XFS file systems currently don't have > that enabled we'll also need to keep the legacy path around. Sure, that's trivially easy to handle in the XFS code once the callouts are in place. But, quite frankly, we can enforce rmap to be enabled enabled because nobody is using a reflink enabled FS w/ DAX right now. Everyone will have to mkfs their filesystems anyway to enable reflink+dax, so we simply don't allow reflink+dax to be enabled unless rmap is also enabled. Simple, easy, trivial. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
