On Sat, Apr 29, 2023 at 08:01:11PM -0300, Jason Gunthorpe wrote: > On Sat, Apr 29, 2023 at 12:21:09AM -0400, Theodore Ts'o wrote: > > > In any case, the file system maintainers' position (mine and I doubt > > Dave Chinner's position has changed) is that if you write to > > file-backed mappings via GUP/RDMA/process_vm_writev, and it causes > > silent data corruption, you get to keep both pieces, and don't go > > looking for us for anything other than sympathy... > > This alone is enough reason to block it. I'm tired of this round and > round and I think we should just say enough, the mm will work to > enforce this view point. Files can only be written through PTEs. > > If this upsets people they can work on fixing it, but at least we > don't have these kernel problems and inconsistencies to deal with. > Indeed, I think there is a broad consensus that FOLL_LONGTERM is such an egregious case that this is the way forward. I will respin with the discussed GUP-fast changes relatively soon and then we can see where that takes us :) > Jason
