Re: [PATCH] btrfs/294: reject zoned devices for now

[David Sterba <dsterba@suse.cz>]

On Tue, Jul 25, 2023 at 08:58:34AM +0800, Qu Wenruo wrote:
> 
> 
> On 2023/7/25 08:22, Naohiro Aota wrote:
> > On Mon, Jul 24, 2023 at 07:10:51AM -0700, Christoph Hellwig wrote:
> >> On Mon, Jul 24, 2023 at 11:04:23AM +0800, Qu Wenruo wrote:
> >>> The test case itself is utilizing RAID5/6, which is not yet supported on
> >>> zoned device.
> >>>
> >>> In the future we would use raid-stripe-tree (RST) feature, but for now
> >>> just reject zoned devices completely.
> >>>
> >>> And since we're here, also update the _fixed_by_kernel_commit lines, as
> >>> the proper fix is already merged upstream.
> >>
> >> Hmm, instead of spreading these checks, shouldn't we check that the
> >> RAID level is supported, and have one single nob for that based off
> >> it, similar to _btrfs_get_profile_configs()?
> >>
> > 
> > That's beneficial. We need to declare which profile the test going to use,
> > something like this?
> > 
> >    _btrfs_require_profile raid5 raid6
> > 
> > or
> > 
> >    _btrfs_require_profile data:dup
> > 
> > as the zoned mode cannot work with the DUP profile for data.
> 
> The latter one sounds good, considering zoned support differs for data 
> and metadata profiles.
> 
> Another thing is, do we have any sysfs files to indicate what profiles 
> we support?
> For now we only have a "zoned" features, but no dedicated zoned specific 
> sysfs files.
> 
> Would that be a good thing to consider?

We don't have it but I think it's a good idea not just for testing, we
export other information as the "features/supported_..." files. The
profiles don't change often but with the incremental support for zoned
this would make it easier for tests to keep up.