On 8/9/19 3:58 PM, ira.weiny@xxxxxxxxx wrote: > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > Add an exclusive lease flag which indicates that the layout mechanism > can not be broken. After studying the rest of these discussions extensively, I think in all cases FL_EXCLUSIVE is better named "unbreakable", rather than exclusive. If you read your sentence above, it basically reinforces that idea: "add an exclusive flag to mean it is unbreakable" is a bit of a disconnect. It would be better to say, Add an "unbreakable" lease flag which indicates that the layout lease cannot be broken. Furthermore, while this may or may not be a way forward on the "we cannot have more than one process take a layout lease on a file/range", it at least stops making it impossible. In other words, no one is going to write a patch that allows sharing an exclusive layout lease--but someone might well update some of these patches here to make it possible to have multiple processes take unbreakable leases on the same file/range. I haven't worked through everything there yet, but again: * FL_UNBREAKABLE is the name you're looking for here, and * I think we want to allow multiple processes to take FL_UNBREAKABLE leases on the same file/range, so that we can make RDMA setups reasonable. By "reasonable" I mean, "no need to have a lead process that owns all the leases". thanks, -- John Hubbard NVIDIA
