On Tue, Mar 26, 2019 at 02:02:47PM -0500, Goldwyn Rodrigues wrote: > This sets S_DAX in inode->i_flags, which can be used with > IS_DAX(). > > The dax option is restricted to non multi-device mounts. > dax interacts with the device directly instead of using bio, so > all bio-hooks which we use for multi-device cannot be performed > here. While regular read/writes could be manipulated with > RAID0/1, mmap() is still an issue. > > Auto-setting free space tree, because dealing with free space > inode (specifically readpages) is a nightmare. > Auto-setting nodatasum because we don't get callback for writing > checksums after mmap()s. Congratulations on getting the bear to dance. But why? To me, the point of btrfs is all the cool stuff it does with built-in checksumming and snapshots and RAID and so on. DAX doesn't let you do any of that, so why would somebody want to use btrfs to manage DAX?