Re: [PATCH] btrfs-progs: output sectorsize related warning message into stdout

[David Sterba <dsterba@suse.cz>]

On Wed, Mar 10, 2021 at 08:18:16AM +0800, Qu Wenruo wrote:
> 
> 
> On 2021/3/9 下午9:33, David Sterba wrote:
> > On Tue, Mar 09, 2021 at 03:39:09PM +0800, Qu Wenruo wrote:
> >> Since commit 90020a760584 ("btrfs-progs: mkfs: refactor how we handle
> >> sectorsize override") we have extra warning message if the sectorsize of
> >> mkfs doesn't match page size.
> >>
> >> But this warning is show as stderr, which makes a lot of fstests cases
> >> failure due to golden output mismatch.
> >
> > Well, no. Using message helpers in progs is what we want to do
> > everywhere, working around fstests output matching design is fixing the
> > problem in the wrong place. That this is fragile has been is known and
> > I want to keep the liberty to adjust output in progs as users need, not
> > as fstests require.
> 
> OK, then I guess the best way to fix the problem is to add sysfs
> interface to export supported rw/ro sectorsize.
> 
> It shouldn't be that complex and would be small enough for next merge
> window.

The subpage support should be advertised somewhere in sysfs so the range
of supported sector sizes sounds like a good idea.