On Sat, Jul 20, 2019 at 07:15:26AM +0000, Damien Le Moal wrote: > Jeff, > > On 2019/07/19 23:25, Jeff Moyer wrote: > > OK, I can see how a file system eases adoption across multiple > > languages, and may, in some cases, be easier to adopt by applications. > > However, I'm not a fan of the file system interface for this usage. > > Once you present a file system, there are certain expectations from > > users, and this fs breaks most of them. > > Your comments got me thinking more about zonefs specifications/features and I am > now wondering if I am not pushing this too far in terms of simplicity. So here > is a new RFC/Question to chew on... While keeping as a target the concept of > "file == zone" or as close to it as possible, what do you think zonefs minimal > feature set should be ? > > One idea I have since a while back now is this: > 1) If a zone is unused, do not show a file for it. This means adding a dynamic > "zone allocation" code and supporting O_CREAT on open, unlink, etc. So have more > normal file system calls behave as with a normal FS. > 2) Allow file names to be decided by the user instead of using a fixed names. > Again, have O_CREAT behave as expected So now you have to implement a persistent directory structure, atomic/transactional updates, etc. You've just added at least 2 orders of magnitude complexity to zonefs and a very substantial amount of additional, ongoing QA to ensure it works correctly. I think keeping it simple by exposing all zones to userspace and leaving it to the application to track/index what zones it is using is the simplest way forward for everyone. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
