Re: [PATCH 15/15] xfs: support T10 protection information

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

On Wed, Jan 21, 2026 at 07:43:23AM +0100, Christoph Hellwig wrote:
> Add support for generating / verifying protection information in the file
> system.  This is largely done by simply setting the IOMAP_F_INTEGRITY
> flag and letting iomap do all of the work.  XFS just has to ensure that
> the data read completions for integrity data are run from user context.
> 
> For zoned writeback, XFS also has to generate the integrity data itself
> as the zoned writeback path is not using the generic writeback_submit
> implementation.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_aops.c  | 47 ++++++++++++++++++++++++++++++++++++++++++----
>  fs/xfs/xfs_iomap.c |  9 ++++++---
>  2 files changed, 49 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index c3c1e149fff4..4baf0a85271c 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -22,6 +22,7 @@
>  #include "xfs_icache.h"
>  #include "xfs_zone_alloc.h"
>  #include "xfs_rtgroup.h"
> +#include <linux/bio-integrity.h>
>  
>  struct xfs_writepage_ctx {
>  	struct iomap_writepage_ctx ctx;
> @@ -661,6 +662,8 @@ xfs_zoned_writeback_submit(
>  		bio_endio(&ioend->io_bio);
>  		return error;
>  	}
> +	if (wpc->iomap.flags & IOMAP_F_INTEGRITY)
> +		fs_bio_integrity_generate(&ioend->io_bio);
>  	xfs_zone_alloc_and_submit(ioend, &XFS_ZWPC(wpc)->open_zone);
>  	return 0;
>  }
> @@ -741,12 +744,43 @@ xfs_vm_bmap(
>  	return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
>  }
>  
> +static void
> +xfs_bio_submit_read(
> +	const struct iomap_iter		*iter,
> +	struct iomap_read_folio_ctx	*ctx)
> +{
> +	struct bio			*bio = ctx->read_ctx;
> +
> +	/* delay read completions to the ioend workqueue */
> +	iomap_init_ioend(iter->inode, bio, ctx->read_ctx_file_offset, 0);
> +	bio->bi_end_io = xfs_end_bio;
> +	submit_bio(bio);
> +}
> +
> +static const struct iomap_read_ops xfs_bio_read_integrity_ops = {
> +	.read_folio_range	= iomap_bio_read_folio_range,
> +	.submit_read		= xfs_bio_submit_read,
> +	.bio_set		= &iomap_ioend_bioset,
> +};
> +
> +static inline const struct iomap_read_ops *bio_read_ops(struct xfs_inode *ip)

xfs_bio_read_ops to avoid conflicts with the block layer?

Otherwise this looks ok to me, so with that fixed,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D


> +{
> +	if (bdev_has_integrity_csum(xfs_inode_buftarg(ip)->bt_bdev))
> +		return &xfs_bio_read_integrity_ops;
> +	return &iomap_bio_read_ops;
> +}
> +
>  STATIC int
>  xfs_vm_read_folio(
> -	struct file		*unused,
> -	struct folio		*folio)
> +	struct file			*file,
> +	struct folio			*folio)
>  {
> -	iomap_bio_read_folio(folio, &xfs_read_iomap_ops);
> +	struct iomap_read_folio_ctx	ctx = {
> +		.cur_folio	= folio,
> +		.ops		= bio_read_ops(XFS_I(file->f_mapping->host)),
> +	};
> +
> +	iomap_read_folio(&xfs_read_iomap_ops, &ctx);
>  	return 0;
>  }
>  
> @@ -754,7 +788,12 @@ STATIC void
>  xfs_vm_readahead(
>  	struct readahead_control	*rac)
>  {
> -	iomap_bio_readahead(rac, &xfs_read_iomap_ops);
> +	struct iomap_read_folio_ctx	ctx = {
> +		.rac		= rac,
> +		.ops		= bio_read_ops(XFS_I(rac->mapping->host)),
> +	};
> +
> +	iomap_readahead(&xfs_read_iomap_ops, &ctx);
>  }
>  
>  static int
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 37a1b33e9045..6ed784894b5a 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -143,11 +143,14 @@ xfs_bmbt_to_iomap(
>  	}
>  	iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
>  	iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
> -	if (mapping_flags & IOMAP_DAX)
> +	iomap->flags = iomap_flags;
> +	if (mapping_flags & IOMAP_DAX) {
>  		iomap->dax_dev = target->bt_daxdev;
> -	else
> +	} else {
>  		iomap->bdev = target->bt_bdev;
> -	iomap->flags = iomap_flags;
> +		if (bdev_has_integrity_csum(iomap->bdev))
> +			iomap->flags |= IOMAP_F_INTEGRITY;
> +	}
>  
>  	/*
>  	 * If the inode is dirty for datasync purposes, let iomap know so it
> -- 
> 2.47.3
> 
>