On Tue, 26 Apr 2022 at 02:36, NeilBrown <neilb@xxxxxxx> wrote: > > On Tue, 26 Apr 2022, Daire Byrne wrote: > > > > I'll stare at fs/nfsd/vfs.c for a bit but I probably lack the > > expertise to make it work. > > Staring at code is good for the soul .... but I'll try to schedule time > to work on this patch again - make it work from nfsd and also make it > handle rename. Yea, I stared at it for quite a while this morning and no amount of coffee was going to help me figure out how best to proceed. If you are able to update this for nfsd then I'll be eternally grateful and do my best to test it under load in an effort to get it all merged. The community here has been so good to us over the last couple of years and it is very much appreciated. It has helped us deliver (oscar winning) movies! To give some brief context as to why this is useful to us (for anyone interested), we utilise NFS re-export extensively to run our batch jobs (movie frame renders) in various remote DCs. In combination with fscache and long term attribute caching, this works great for exposing our (read often) onprem storage to the remote DCs (with varying latencies). But batch jobs have a tendency to start related tasks on many clients at the same time with their results or logs being written to big common directories. And by writing through the re-export server, we often hit this limitation with parallel file creates which slows everything down. We have tried to avoid large directories where possible, but it's hard to catch and fix all the cases. Using an NFS re-export server works 95% of the time for our workloads (after much help from this community), so we are just trying to pick away at the last 5% of edge cases. One of the disadvantages of the re-export server in the middle, is that we lose some of the natural parallelism that directly connected clients would otherwise have. And this becomes very noticeable once the latency goes above 20ms. Cheers, Daire > > It's also not entirely clear that this parallel creates RFC patch will > > ever make it into mainline? > > I hope it will eventually, but I have no idea when that might be. > > Thanks for your continued interest, > NeilBrown
