On Wed, Jun 13 2018 at 8:11pm -0400, Luis R. Rodriguez <mcgrof@xxxxxxxxxx> wrote: > Setting up a zoned disks in a generic form is not so trivial. There > is also quite a bit of tribal knowledge with these devices which is not > easy to find. > > The currently supplied demo script works but it is not generic enough to be > practical for Linux distributions or even developers which often move > from one kernel to another. > > This tries to put a bit of this tribal knowledge into an initial udev > rule for development with the hopes Linux distributions can later > deploy. Three rule are added. One rule is optional for now, it should be > extended later to be more distribution-friendly and then I think this > may be ready for consideration for integration on distributions. > > 1) scheduler setup This is wrong.. if zoned devices are so dependent on deadline or mq-deadline then the kernel should allow them to be hardcoded. I know Jens removed the API to do so but the fact that drivers need to rely on hacks like this udev rule to get a functional device is proof we need to allow drivers to impose the scheduler used. > 2) backlist f2fs devices There should porbably be support in dm-zoned for detecting whether a zoned device was formatted with f2fs (assuming there is a known f2fs superblock)? > 3) run dmsetup for the rest of devices automagically running dmsetup directly from udev to create a dm-zoned target is very much wrong. It just gets in the way of proper support that should be add to appropriate tools that admins use to setup their zoned devices. For instance, persistent use of dm-zoned target should be made reliable with a volume manager.. In general this udev script is unwelcome and makes things way worse for the long-term success of zoned devices. I don't dispute there is an obvious void for how to properly setup zoned devices, but this script is _not_ what should fill that void. So a heartfelt: Nacked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
