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From:   "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
To:     aravind.ramesh@opensource.wdc.com
Cc:     Hans Holmberg <Hans.Holmberg@wdc.com>,
        Jens Axboe <axboe@kernel.dk>,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        hch@infradead.org,
        Matias =?utf-8?Q?Bj=C3=B8rling?= <Matias.Bjorling@wdc.com>,
        open list <linux-kernel@vger.kernel.org>,
        Damien Le Moal <dlemoal@kernel.org>, gost.dev@samsung.com,
        Minwoo Im <minwoo.im.dev@gmail.com>,
        Ming Lei <ming.lei@redhat.com>
Subject: Re: [PATCH v4 0/4] ublk: add zoned storage support
Date:   Fri, 30 Jun 2023 16:26:28 +0200
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Message-ID: <87edltdnp8.fsf@metaspace.dk>
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aravind.ramesh@opensource.wdc.com writes:

>> =EF=BB=BFOn 29/06/23, 12:37 AM, "Andreas Hindborg" <nmi@metaspace.dk
>> <mailto:nmi@metaspace.dk>> wrote:
>> From: Andreas Hindborg <a.hindborg@samsung.com
>> <mailto:a.hindborg@samsung.com>>
>> Hi All,
>> This patch set adds zoned storage support to `ublk`. The first two patch=
es
>> does
>> some house cleaning in preparation for the last two patches. The third p=
atch
>> adds support for report_zones and the following operations:
>>=20
>
> Just to clarify, we do need you ublk user space patches
> to create a ublk device node (with these patches in kernel), right ?

I provide an example implementation. I put a link in the cover letter,
but I think the sentence referring to the link got lost, thanks for
pointing out.

https://github.com/metaspace/ubdsrv/commit/7de0d901c329fde7dc5a2e998952dd88=
bf5e668b

This implementation is based on Ming's ubdsrv code. You do not need to
use this one, you can write your own. I am also working on an
implementation in Rust, but that is still very early. I think Ming is
also writing a Rust library for user space ublk devices.

But currently my patched ubdsrv is the only user space implementation
supporting zoned ublk devices (with the loop and null targets).

>
>> - REQ_OP_ZONE_OPEN
>> - REQ_OP_ZONE_CLOSE
>> - REQ_OP_ZONE_FINISH
>> - REQ_OP_ZONE_RES
>
> REQ_OP_ZONE_RESET

Thanks!

>
>> The last patch adds support for REQ_OP_ZONE_APPEND.
>> v3 [2] -> v4 changes:
>> - Split up v3 patches
>> - Add zone append support
>> - Change order of variables in `ublk_report_zones`
>> Read/write and zone operations are tested with zenfs [3].
>> The zone append path is tested with fio -> zonefs -> ublk -> null_blk.
>> The implementation of zone append requires ublk user copy feature, and
>> therefore
>> the series is based on branch for-next (6afa337a3789) of [4].
>> [1]
>> https://github.com/metaspace/ubdsrv/commit/7de0d901c329fde7dc5a2e998952d=
d88bf5e668b
>> <https://github.com/metaspace/ubdsrv/commit/7de0d901c329fde7dc5a2e998952=
dd88bf5e668b>
>> [2]
>> https://lore.kernel.org/linux-block/20230316145539.300523-1-nmi@metaspac=
e.dk
>> <mailto:20230316145539.300523-1-nmi@metaspace.dk>/
>> [3] https://github.com/westerndigitalcorporation/zenfs
>> <https://github.com/westerndigitalcorporation/zenfs>
>> [4] https://git.kernel.dk/linux.git <https://git.kernel.dk/linux.git>
>> Andreas Hindborg (4):
>> ublk: change ublk IO command defines to enum
>> ublk: move types to shared header file
>> ublk: enable zoned storage support
>> ublk: add zone append
>> MAINTAINERS | 2 +
>> drivers/block/Kconfig | 4 +
>> drivers/block/Makefile | 4 +-
>> drivers/block/ublk_drv-zoned.c | 155 +++++++++++++++++++++++++++++++++
>> drivers/block/ublk_drv.c | 150 +++++++++++++++++++------------
>> drivers/block/ublk_drv.h | 71 +++++++++++++++
>> include/uapi/linux/ublk_cmd.h | 38 ++++++--
>> 7 files changed, 363 insertions(+), 61 deletions(-)
>> create mode 100644 drivers/block/ublk_drv-zoned.c
>> create mode 100644 drivers/block/ublk_drv.h
>> base-commit: 3261ea42710e9665c9151006049411bd23b5411f
>
> Regards,
> Aravind