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    SubjectRe: [PATCH 2/2] nvme: add emulation for zone-append
    On 19.08.2020 13:25, Jens Axboe wrote:
    >On 8/19/20 12:11 PM, David Fugate wrote:
    >> On Tue, 2020-08-18 at 07:12 +0000, Christoph Hellwig wrote:
    >>> On Tue, Aug 18, 2020 at 10:59:36AM +0530, Kanchan Joshi wrote:
    >>>> If drive does not support zone-append natively, enable emulation
    >>>> using
    >>>> regular write.
    >>>> Make emulated zone-append cmd write-lock the zone, preventing
    >>>> concurrent append/write on the same zone.
    >>>
    >>> I really don't think we should add this. ZNS and the Linux support
    >>> were all designed with Zone Append in mind, and then your company did
    >>> the nastiest possible move violating the normal NVMe procedures to
    >>> make
    >>> it optional. But that doesn't change the fact the Linux should keep
    >>> requiring it, especially with the amount of code added here and how
    >>> it
    >>> hooks in the fast path.
    >>
    >> Intel does not support making *optional* NVMe spec features *required*
    >> by the NVMe driver.
    >
    >It's not required, the driver will function quite fine without it. If you
    >want to use ZNS it's required. The Linux driver thankfully doesn't need
    >any vendor to sign off on what it can or cannot do, or what features
    >are acceptable.
    >
    >> It's forgivable WDC's accepted contribution didn't work with other
    >> vendors' devices choosing not to implement the optional Zone Append,
    >> but it's not OK to reject contributions remedying this. Provided
    >> there's no glaring technical issues, Samsung's contribution should be
    >> accepted to maintain both spec compliance as well as vendor neutrality.
    >
    >It's *always* ok to reject contributions, if those contributions cause
    >maintainability issues, unacceptable slowdowns, or whatever other issue
    >that the maintainers of said driver don't want to deal with. Any
    >contribution should be judged on merit, not based on political decisions
    >or opinions. Obviously this thread reeks of it.
    >

    I'll reply here, where the discussion diverges from this particular
    patch.

    We will stop pushing for this emulation. We have a couple of SSDs where
    we disabled Append, we implemented support for them, and we wanted to
    push the changes upstream. That's it. This is no politics not a
    conspiracy against the current ZNS spec. We spent a lot of time working
    on this spec and are actually doing a fair amount of work to support
    Append other places in the stack. In any case, the fuzz stops here.

    Javier

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