On Mon, Feb 04, 2019 at 06:21:39PM +0000, Christopher Lameter wrote: > On Mon, 4 Feb 2019, Jason Gunthorpe wrote: > > > On Mon, Feb 04, 2019 at 05:14:19PM +0000, Christopher Lameter wrote: > > > Frankly I still think this does not solve anything. > > > > > > Concurrent write access from two sources to a single page is simply wrong. > > > You cannot make this right by allowing long term RDMA pins in a filesystem > > > and thus the filesystem can never update part of its files on disk. > > > > Fundamentally this patch series is fixing O_DIRECT to not crash the > > kernel in extreme cases.. RDMA has the same problem, but it is much > > easier to hit. > > O_DIRECT is the same issue. O_DIRECT addresses always have been in > anonymous memory or special file systems. That's never been a constraint that's existed.