Re: [PATCH] xfs: add a test that zoned file systems with rump RTG can't be mounted

[Christoph Hellwig <hch@lst.de>]

On Wed, Dec 10, 2025 at 08:50:28AM -0800, Darrick J. Wong wrote:
> > +_scratch_mkfs > /dev/null 2>&1
> > +blocks=$(_scratch_xfs_db -c 'sb 0' -c 'print rblocks' | awk '{print $3}')
> 
> blocks="$(_scratch_xfs_get_metadata_field rblocks 'sb 0')"

Ah, I had a vague memory something like this existed but could not
find it.

> > +blocks=$((blocks - 4096))
> > +_scratch_xfs_db -x -c 'sb 0' -c "write -d rblocks $blocks" > /dev/null 2>&1
> > +_scratch_xfs_db -x -c 'sb 0' -c "write -d rextents $blocks" > /dev/null 2>&1
> > +_try_scratch_mount || _notrun "Can't mount rump RTG file system"
> 
> Doesn't the _notrun here cause the test to be "skipped" when in fact it
> actually exhibits the behavior that you want (i.e. it passes)?

Yes.  Which sort of does what's intended (fail on broken behavior) but
in a very odd way.  I'll do this in a nicer way.