On Fri, Aug 23, 2019 at 01:23:45PM +1000, Dave Chinner wrote: > > But the fact that RDMA, and potentially others, can "pass the > > pins" to other processes is something I spent a lot of time trying to work out. > > There's nothing in file layout lease architecture that says you > can't "pass the pins" to another process. All the file layout lease > requirements say is that if you are going to pass a resource for > which the layout lease guarantees access for to another process, > then the destination process already have a valid, active layout > lease that covers the range of the pins being passed to it via the > RDMA handle. How would the kernel detect and enforce this? There are many ways to pass a FD. IMHO it is wrong to try and create a model where the file lease exists independently from the kernel object relying on it. In other words the IB MR object itself should hold a reference to the lease it relies upon to function properly. Then we don't have to wreck the unix FD model to fit this in. Jason
