dm integrity: fix a crash if "recalculate" used without "internal_hash"

Recalculate can only be specified with internal_hash.

Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

drivers/md/dm-integrity.c

@@ -4235,6 +4235,12 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 			r = -ENOMEM;
 			goto bad;
 		}
+	} else {
+		if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING)) {
+			ti->error = "Recalculate can only be specified with internal_hash";
+			r = -EINVAL;
+			goto bad;
+		}
 	}
 
 	ic->bufio = dm_bufio_client_create(ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev,