On 5/7/20 12:55 PM, Jeremy Allison wrote: > On Thu, May 07, 2020 at 12:35:42PM -0600, Jens Axboe wrote: >> On 5/7/20 12:31 PM, Jeremy Allison wrote: >>> >>> Look at how quickly someone spotted disk corruption >>> because of the change in userspace-visible behavior >>> of the io_uring interface. We only shipped that code >>> 03 March 2020 and someone *already* found it. >> >> I _think_ that will only happen on regular files if you use RWF_NOWAIT >> or similar, for regular blocking it should not happen. So I don't think >> you're at risk there, though I do think that anyone should write >> applications with short IOs in mind or they will run into surprises down >> the line. Should have been more clear! > > Well we definitely considered short IOs writing the > server code, but as the protocol allows that to be > visible to the clients (in fact it has explicit > fields meant to deal with it) it wasn't considered > vital to hide them from clients. Yes, and in case my reply wasn't totally clear, it was more of a general observation, not directed at Samba specifically! > We'll certainly fix up short reads for the iouring > module, but it's less clear we should mess with > our existing blocking threaded pread/pwrite code > to deal with them. Possibly goes into the bucket > of "belt and braces, couldn't possibly hurt" :-). Agree, belts and suspenders for the regular pread/pwrite, that's a fair position. > Thanks for the clarification ! Thanks for getting this fleshed out! Impressed with the speed at which we got to the bottom of this. -- Jens Axboe
