xfs: support T10 protection information

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>
Link: https://patch.msgid.link/20260223132021.292832-17-hch@lst.de
Tested-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Christoph Hellwig

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;
 }
@@ -741,20 +744,56 @@ 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;
+
+	/* defer 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_iomap_read_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 *
+xfs_get_iomap_read_ops(
+	const struct address_space	*mapping)
+{
+	struct xfs_inode		*ip = XFS_I(mapping->host);
+
+	if (bdev_has_integrity_csum(xfs_inode_buftarg(ip)->bt_bdev))
+		return &xfs_iomap_read_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 };
+
+	ctx.ops = xfs_get_iomap_read_ops(folio->mapping);
+	iomap_read_folio(&xfs_read_iomap_ops, &ctx, NULL);
 	return 0;
 }
 
 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 };
+
+	ctx.ops = xfs_get_iomap_read_ops(rac->mapping),
+	iomap_readahead(&xfs_read_iomap_ops, &ctx, NULL);
 }
 
 static int

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