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Date:   Wed, 12 Jun 2019 19:51:38 +0200
From:   David Sterba <dsterba@suse.cz>
To:     Naohiro Aota <naohiro.aota@wdc.com>
Cc:     linux-btrfs@vger.kernel.org, David Sterba <dsterba@suse.com>,
        Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        Qu Wenruo <wqu@suse.com>, Nikolay Borisov <nborisov@suse.com>,
        linux-kernel@vger.kernel.org, Hannes Reinecke <hare@suse.com>,
        linux-fsdevel@vger.kernel.org,
        Damien Le Moal <damien.lemoal@wdc.com>,
        Matias =?iso-8859-1?Q?Bj=F8rling?= <mb@lightnvm.io>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH v2 00/19] btrfs zoned block device support
Message-ID: <20190612175138.GT3563@twin.jikos.cz>
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        Qu Wenruo <wqu@suse.com>, Nikolay Borisov <nborisov@suse.com>,
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        Damien Le Moal <damien.lemoal@wdc.com>,
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        Johannes Thumshirn <jthumshirn@suse.de>,
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On Fri, Jun 07, 2019 at 10:10:06PM +0900, Naohiro Aota wrote:
> btrfs zoned block device support
> 
> This series adds zoned block device support to btrfs.

The overall design sounds ok.

I skimmed through the patches and the biggest task I see is how to make
the hmzoned adjustments and branches less visible, ie. there are too
many if (hmzoned) { do something } standing out. But that's merely a
matter of wrappers and maybe an abstraction here and there.

How can I test the zoned devices backed by files (or regular disks)? I
searched for some concrete example eg. for qemu or dm-zoned, but closest
match was a text description in libzbc README that it's possible to
implement. All other howtos expect a real zoned device.

Merge target is 5.3 or later, we'll see how things will go. I'm
expecting that we might need some time to get feedback about the
usability as there's no previous work widely used that we can build on
top of.