Re: [PATCH v11 10/10] xfs: enable block size larger than page size support

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

On Fri, Jul 26, 2024 at 01:59:56PM +0200, Pankaj Raghav (Samsung) wrote:
> From: Pankaj Raghav <p.raghav@samsung.com>
> 
> Page cache now has the ability to have a minimum order when allocating
> a folio which is a prerequisite to add support for block size > page
> size.
> 
> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  fs/xfs/libxfs/xfs_ialloc.c |  5 +++++
>  fs/xfs/libxfs/xfs_shared.h |  3 +++
>  fs/xfs/xfs_icache.c        |  6 ++++--
>  fs/xfs/xfs_mount.c         |  1 -
>  fs/xfs/xfs_super.c         | 28 ++++++++++++++++++++--------
>  include/linux/pagemap.h    | 13 +++++++++++++
>  6 files changed, 45 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> index 0af5b7a33d055..1921b689888b8 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.c
> +++ b/fs/xfs/libxfs/xfs_ialloc.c
> @@ -3033,6 +3033,11 @@ xfs_ialloc_setup_geometry(
>  		igeo->ialloc_align = mp->m_dalign;
>  	else
>  		igeo->ialloc_align = 0;
> +
> +	if (mp->m_sb.sb_blocksize > PAGE_SIZE)
> +		igeo->min_folio_order = mp->m_sb.sb_blocklog - PAGE_SHIFT;
> +	else
> +		igeo->min_folio_order = 0;
>  }
>  
>  /* Compute the location of the root directory inode that is laid out by mkfs. */
> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
> index 2f7413afbf46c..33b84a3a83ff6 100644
> --- a/fs/xfs/libxfs/xfs_shared.h
> +++ b/fs/xfs/libxfs/xfs_shared.h
> @@ -224,6 +224,9 @@ struct xfs_ino_geometry {
>  	/* precomputed value for di_flags2 */
>  	uint64_t	new_diflags2;
>  
> +	/* minimum folio order of a page cache allocation */
> +	unsigned int	min_folio_order;
> +
>  };
>  
>  #endif /* __XFS_SHARED_H__ */
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index cf629302d48e7..0fcf235e50235 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -88,7 +88,8 @@ xfs_inode_alloc(
>  
>  	/* VFS doesn't initialise i_mode! */
>  	VFS_I(ip)->i_mode = 0;
> -	mapping_set_large_folios(VFS_I(ip)->i_mapping);
> +	mapping_set_folio_min_order(VFS_I(ip)->i_mapping,
> +				    M_IGEO(mp)->min_folio_order);
>  
>  	XFS_STATS_INC(mp, vn_active);
>  	ASSERT(atomic_read(&ip->i_pincount) == 0);
> @@ -325,7 +326,8 @@ xfs_reinit_inode(
>  	inode->i_uid = uid;
>  	inode->i_gid = gid;
>  	inode->i_state = state;
> -	mapping_set_large_folios(inode->i_mapping);
> +	mapping_set_folio_min_order(inode->i_mapping,
> +				    M_IGEO(mp)->min_folio_order);
>  	return error;
>  }
>  
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index 3949f720b5354..c6933440f8066 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -134,7 +134,6 @@ xfs_sb_validate_fsb_count(
>  {
>  	uint64_t		max_bytes;
>  
> -	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
>  	ASSERT(sbp->sb_blocklog >= BBSHIFT);
>  
>  	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 27e9f749c4c7f..b2f5a1706c59d 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1638,16 +1638,28 @@ 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; Only block size (%ld) or less is supported",
> +			mp->m_sb.sb_blocksize, max_folio_size);

Dumb nit: Please indent ^^^ this second line so that it doesn't start on
the same column as the separate statement below it.

--D

> +			error = -ENOSYS;
> +			goto out_free_sb;
> +		}
> +
> +		xfs_warn(mp,
> +"EXPERIMENTAL: V5 Filesystem with Large Block Size (%d bytes) enabled.",
> +			mp->m_sb.sb_blocksize);
>  	}
>  
>  	/* Ensure this filesystem fits in the page cache limits */
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 3a876d6801a90..61a7649d86e57 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -373,6 +373,19 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
>  #define MAX_XAS_ORDER		(XA_CHUNK_SHIFT * 2 - 1)
>  #define MAX_PAGECACHE_ORDER	min(MAX_XAS_ORDER, PREFERRED_MAX_PAGECACHE_ORDER)
>  
> +/*
> + * mapping_max_folio_size_supported() - Check the max folio size supported
> + *
> + * The filesystem should call this function at mount time if there is a
> + * requirement on the folio mapping size in the page cache.
> + */
> +static inline size_t mapping_max_folio_size_supported(void)
> +{
> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
> +		return 1U << (PAGE_SHIFT + MAX_PAGECACHE_ORDER);
> +	return PAGE_SIZE;
> +}
> +
>  /*
>   * mapping_set_folio_order_range() - Set the orders supported by a file.
>   * @mapping: The address space of the file.
> -- 
> 2.44.1
> 
>