On Fri, Aug 25, 2017 at 08:40:32AM -0700, Christoph Hellwig wrote: > On Fri, Aug 25, 2017 at 11:14:45AM -0400, Theodore Ts'o wrote: > > > I don't know of anyone that actually uses the flag. If someone did > > > that would probably run into problems like changing that changing it > > > on a file that's currently mmaped would crash an burn badly. > > > > Crash and burn meaning the *kernel* will crash and burn? Or will data > > be damaged? > > > > Given that, maybe XFS should withdraw support for the DAX and hope no > > one is actually using it? > > Nah, -o dax works very well. It's just the flag instead of the -o dax > option or rather switching it on a mapped file will probably be very dangerous. Sorry, I was suggested XFS withdrawing support for the pre-file dax flag. I thought part of the argument for why ext4 should accept this patch is that XFS already has the per-file DAX flag? - Ted