dm: add integrity support

This patch provides support for data integrity passthrough in the device
mapper.

 - If one or more component devices support integrity an integrity
   profile is preallocated for the DM device.

 - If all component devices have compatible profiles the DM device is
   flagged as capable.

 - Handle integrity metadata when splitting and cloning bios.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 788ba96a6256..25d86e2c01f2 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -700,6 +700,12 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
         clone->bi_io_vec->bv_len = clone->bi_size;
         clone->bi_flags |= 1 << BIO_CLONED;
 
+        if (bio_integrity(bio)) {
+                bio_integrity_clone(clone, bio, GFP_NOIO);
+                bio_integrity_trim(clone,
+                                   bio_sector_offset(bio, idx, offset), len);
+        }
+
         return clone;
 }
 
@@ -721,6 +727,14 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
         clone->bi_size = to_bytes(len);
         clone->bi_flags &= ~(1 << BIO_SEG_VALID);
 
+        if (bio_integrity(bio)) {
+                bio_integrity_clone(clone, bio, GFP_NOIO);
+
+                if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
+                        bio_integrity_trim(clone,
+                                           bio_sector_offset(bio, idx, 0), len);
+        }
+
         return clone;
 }
 
@@ -1193,6 +1207,7 @@ static void free_dev(struct mapped_device *md)
         mempool_destroy(md->tio_pool);
         mempool_destroy(md->io_pool);
         bioset_free(md->bs);
+        blk_integrity_unregister(md->disk);
         del_gendisk(md->disk);
         free_minor(minor);