Re: [PATCH v10 10/10] xfs: enable block size larger than page size support

[Matthew Wilcox <willy@infradead.org>]

On Mon, Jul 15, 2024 at 11:44:57AM +0200, Pankaj Raghav (Samsung) wrote:
> +++ b/fs/xfs/xfs_super.c
> @@ -1638,16 +1638,30 @@ xfs_fs_fill_super(
>  		goto out_free_sb;
>  	}
>  
> -	/*
> -	 * Until this is fixed only page-sized or smaller data blocks work.
> -	 */
>  	if (mp->m_sb.sb_blocksize > PAGE_SIZE) {
> -		xfs_warn(mp,
> -		"File system with blocksize %d bytes. "
> -		"Only pagesize (%ld) or less will currently work.",
> +		size_t max_folio_size = mapping_max_folio_size_supported();
> +
> +		if (!xfs_has_crc(mp)) {
> +			xfs_warn(mp,
> +"V4 Filesystem with blocksize %d bytes. Only pagesize (%ld) or less is supported.",
>  				mp->m_sb.sb_blocksize, PAGE_SIZE);
> -		error = -ENOSYS;
> -		goto out_free_sb;
> +			error = -ENOSYS;
> +			goto out_free_sb;
> +		}
> +
> +		if (mp->m_sb.sb_blocksize > max_folio_size) {
> +			xfs_warn(mp,
> +"block size (%u bytes) not supported; maximum folio size supported in "\
> +"the page cache is (%ld bytes). Check MAX_PAGECACHE_ORDER (%d)",
> +			mp->m_sb.sb_blocksize, max_folio_size,
> +			MAX_PAGECACHE_ORDER);

Again, too much message.  Way too much.  We shouldn't even allow block
devices to be created if their block size is larger than the max supported
by the page cache.