Messages in this thread | | | Subject | Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl | From | Sagi Grimberg <> | Date | Thu, 22 Aug 2019 12:17:39 -0700 |
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>>>> 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...
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