Re: [PATCH v2 00/19] btrfs zoned block device support

[Naohiro Aota]

On 2019/06/13 2:50, David Sterba wrote:
> 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.

Sure. I'll add some more abstractions in the next version.

> 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.

You can use tcmu-runer [1] to create an emulated zoned device backed by 
a regular file. Here is a setup how-to:
http://zonedstorage.io/projects/tcmu-runner/#compilation-and-installation

[1] https://github.com/open-iscsi/tcmu-runner

> 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.
>