[PATCH 2/2] xfs: disable large folio support in xfile_create

[Darrick J. Wong]

On Wed, Jan 10, 2024 at 10:21:09AM +0100, Christoph Hellwig wrote:
> The xfarray code will crash if large folios are force enabled using:
> 
>    echo force > /sys/kernel/mm/transparent_hugepage/shmem_enabled
> 
> Fixing this will require a bit of an API change, and prefeably sorting out
> the hwpoison story for pages vs folio and where it is placed in the shmem
> API.  For now use this one liner to disable large folios.
> 
> Reported-by: Darrick J. Wong <djwong at kernel.org>
> Signed-off-by: Christoph Hellwig <hch at lst.de>

Can someone who knows more about shmem.c than I do please review
https://lore.kernel.org/linux-xfs/20240103084126.513354-4-hch@lst.de/
so that I can feel slightly more confident as hch and I sort through the
xfile.c issues?

For this patch,
Reviewed-by: Darrick J. Wong <djwong at kernel.org>

--D

> ---
>  fs/xfs/scrub/xfile.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c
> index 090c3ead43fdf1..1a8d1bedd0b0dc 100644
> --- a/fs/xfs/scrub/xfile.c
> +++ b/fs/xfs/scrub/xfile.c
> @@ -94,6 +94,11 @@ xfile_create(
>  
>  	lockdep_set_class(&inode->i_rwsem, &xfile_i_mutex_key);
>  
> +	/*
> +	 * We're not quite ready for large folios yet.
> +	 */
> +	mapping_clear_large_folios(inode->i_mapping);
> +
>  	trace_xfile_create(xf);
>  
>  	*xfilep = xf;
> -- 
> 2.39.2
> 
>