On 2019-08-22 1:17 p.m., Sagi Grimberg wrote: > >>>>> I don't understand why we don't limit a regular ctrl to single >>>>> access and we do it for the PT ctrl. >>>>> >>>>> I guess the block layer helps to sync between multiple access in >>>>> parallel but we can do it as well. >>>>> >>>>> Also, let's say you limit the access to this subsystem to 1 user, >>>>> the bdev is still accessibly for local user and also you can create >>>>> a different subsystem that will use this device (PT and non-PT ctrl). >>>>> >>>>> Sagi, >>>>> >>>>> can you explain the trouble you meant and how this limitation solve >>>>> it ? >>>> >>>> Its different to emulate the controller with all its admin >>>> commands vs. passing it through to the nvme device.. (think of >>>> format nvm) >>>> >>>> >>>> >>> we don't need to support format command for PT ctrl as we don't >>> support other commands such create_sq/cq. >> >> That is just an example, basically every command that we are not aware >> of we simply passthru to the drive without knowing the implications >> on a multi-host environment.. > > If we were to change the logic of nvmet_parse_passthru_admin_cmd to > have the default case do nvmet_parse_admin_cmd, and only have > the vendor-specific space opcodes do nvmet_passthru_execute_cmd > then I could not see at the moment how we can break a multi-host > export... That makes sense. I'll make that change and resend a v8 next week. Logan
