Re: [PATCH] xfs/541: _notrun if the file system can't mount

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Jan 29, 2025 at 06:49:18AM +0100, Christoph Hellwig wrote:
> On Tue, Jan 28, 2025 at 11:25:06AM -0800, Darrick J. Wong wrote:
> > On Tue, Jan 28, 2025 at 08:14:48AM +0100, Christoph Hellwig wrote:
> > > A file system created without an RT section might not be able to mount
> > > with an rtdev specified if the RT device has a larger LBA size.
> > 
> > Where does the mount failure occur?  The initial mount (where we specify
> > -o rtdev but sb_rblocks is still zero) should succeed because
> > xfs_rtmount_init ignores m_rtdev_targp if !rblocks, right?  So it's only
> > when you get to growfs and we try to read the device that things fail?
> 
> There only is a single mount in the test.
> 
> The test only clears the rtdev for the mkfs call, not the mount call.
> As XFS doesn't allow adding a new rtdev at runtime, just expanding the
> file system to the already passed but not actually used rt device in
> growfs that's actually needed, even if it sounds counterintuitive.
> 
> (that being said I sent the patch directly from my zoned branch,
> so it won't apply as-is due to context issues)

Gross, it's the set_blocksize call in xfs_setsize_buftarg that trips
everything up.  But, it makes sense that one cannot mix sector sizes nor
mount an rtdev with a larger sector size than what's configured on the
data device.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D