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Date:   Wed, 4 Oct 2023 18:55:45 +1030
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Subject: Re: [PATCH v3 0/4] btrfs: RAID stripe tree updates
Content-Language: en-US
To:     Johannes Thumshirn <johannes.thumshirn@wdc.com>,
        Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>
Cc:     Qu Wenru <wqu@suse.com>, Damien Le Moal <dlemoal@kernel.org>,
        Naohiro Aota <naohiro.aota@wdc.com>,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20231004-rst-updates-v3-0-7729c4474ade@wdc.com>
From:   Qu Wenruo <quwenruo.btrfs@gmx.com>
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Precedence: bulk


On 2023/10/4 18:26, Johannes Thumshirn wrote:
> This batch of RST updates contains the on-disk format changes Qu
> suggested. It drastically simplifies the write and path, especially for
> RAID10.
>
> Instead of recording all strides of a striped RAID into one stripe tree
> entry, we create multiple entries per stride. This allows us to remove t=
he
> length in the stride as we can use the length from the key. Using this
> method RAID10 becomes RAID1 and RAID0 becomes single from the point of
> view of the stripe tree.

Great the idea can simplify the code.
So I'm very glad I can provide some help on RST.

Although one concern is about the compatibility, but I guess since rst
is still covered under experimental flags for progs, we can more or less
ignore the compatibility for now?

The other concern is, how would those patches be merged, would David
just fold them, and we can check the misc-next, or there would be
another branch for us to view the code?

Thanks,
Qu
>
> ---
> - Link to first batch: https://lore.kernel.org/r/20230918-rst-updates-v1=
-0-17686dc06859@wdc.com
> - Link to second batch: https://lore.kernel.org/r/20230920-rst-updates-v=
2-0-b4dc154a648f@wdc.com
>
> ---
> Johannes Thumshirn (4):
>        btrfs: change RST write
>        btrfs: remove stride length check on read
>        btrfs: remove raid stride length in tree printer
>        btrfs: remove stride length from on-disk format
>
>   fs/btrfs/accessors.h            |   2 -
>   fs/btrfs/print-tree.c           |   5 +-
>   fs/btrfs/raid-stripe-tree.c     | 173 ++------------------------------=
--------
>   include/uapi/linux/btrfs_tree.h |   2 -
>   4 files changed, 7 insertions(+), 175 deletions(-)
> ---
> base-commit: 8d3aed36ee6cac09c7bd6bee6ad67dc2a35615af
> change-id: 20230915-rst-updates-8c55784ca4ef
>
> Best regards,