md: Push down data integrity code to personalities.

This patch replaces md_integrity_check() by two new public functions:
md_integrity_register() and md_integrity_add_rdev() which are both
personality-independent.

md_integrity_register() is called from the ->run and ->hot_remove
methods of all personalities that support data integrity. The
function iterates over the component devices of the array and
determines if all active devices are integrity capable and if their
profiles match. If this is the case, the common profile is registered
for the mddev via blk_integrity_register().

The second new function, md_integrity_add_rdev() is called from the
->hot_add_disk methods, i.e. whenever a new device is being added
to a raid array. If the new device does not support data integrity,
or has a profile different from the one already registered, data
integrity for the mddev is disabled.

For raid0 and linear, only the call to md_integrity_register() from
the ->run method is necessary.

Signed-off-by: Andre Noll <[e-mail]>
Signed-off-by: NeilBrown <[e-mail]>

drivers/md/linear.c

···
 	mddev->queue->unplug_fn = linear_unplug;
 	mddev->queue->backing_dev_info.congested_fn = linear_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
+	md_integrity_register(mddev);
 	return 0;
 }
 

drivers/md/md.c

···
 
 static LIST_HEAD(pending_raid_disks);
 
-static void md_integrity_check(mdk_rdev_t *rdev, mddev_t *mddev)
+/*
+ * Try to register data integrity profile for an mddev
+ *
+ * This is called when an array is started and after a disk has been kicked
+ * from the array. It only succeeds if all working and active component devices
+ * are integrity capable with matching profiles.
+ */
+int md_integrity_register(mddev_t *mddev)
 {
-	struct mdk_personality *pers = mddev->pers;
-	struct gendisk *disk = mddev->gendisk;
-	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
-	struct blk_integrity *bi_mddev = blk_get_integrity(disk);
+	mdk_rdev_t *rdev, *reference = NULL;
 
-	/* Data integrity passthrough not supported on RAID 4, 5 and 6 */
-	if (pers && pers->level >= 4 && pers->level <= 6)
-		return;
-
-	/* If rdev is integrity capable, register profile for mddev */
-	if (!bi_mddev && bi_rdev) {
-		if (blk_integrity_register(disk, bi_rdev))
-			printk(KERN_ERR "%s: %s Could not register integrity!\n",
-			       __func__, disk->disk_name);
-		else
-			printk(KERN_NOTICE "Enabling data integrity on %s\n",
-			       disk->disk_name);
-		return;
+	if (list_empty(&mddev->disks))
+		return 0; /* nothing to do */
+	if (blk_get_integrity(mddev->gendisk))
+		return 0; /* already registered */
+	list_for_each_entry(rdev, &mddev->disks, same_set) {
+		/* skip spares and non-functional disks */
+		if (test_bit(Faulty, &rdev->flags))
+			continue;
+		if (rdev->raid_disk < 0)
+			continue;
+		/*
+		 * If at least one rdev is not integrity capable, we can not
+		 * enable data integrity for the md device.
+		 */
+		if (!bdev_get_integrity(rdev->bdev))
+			return -EINVAL;
+		if (!reference) {
+			/* Use the first rdev as the reference */
+			reference = rdev;
+			continue;
+		}
+		/* does this rdev's profile match the reference profile? */
+		if (blk_integrity_compare(reference->bdev->bd_disk,
+				rdev->bdev->bd_disk) < 0)
+			return -EINVAL;
 	}
-
-	/* Check that mddev and rdev have matching profiles */
-	if (blk_integrity_compare(disk, rdev->bdev->bd_disk) < 0) {
-		printk(KERN_ERR "%s: %s/%s integrity mismatch!\n", __func__,
-		       disk->disk_name, rdev->bdev->bd_disk->disk_name);
-		printk(KERN_NOTICE "Disabling data integrity on %s\n",
-		       disk->disk_name);
-		blk_integrity_unregister(disk);
+	/*
+	 * All component devices are integrity capable and have matching
+	 * profiles, register the common profile for the md device.
+	 */
+	if (blk_integrity_register(mddev->gendisk,
+			bdev_get_integrity(reference->bdev)) != 0) {
+		printk(KERN_ERR "md: failed to register integrity for %s\n",
+			mdname(mddev));
+		return -EINVAL;
 	}
+	printk(KERN_NOTICE "md: data integrity on %s enabled\n",
+		mdname(mddev));
+	return 0;
 }
+EXPORT_SYMBOL(md_integrity_register);
+
+/* Disable data integrity if non-capable/non-matching disk is being added */
+void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
+{
+	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
+	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
+
+	if (!bi_mddev) /* nothing to do */
+		return;
+	if (rdev->raid_disk < 0) /* skip spares */
+		return;
+	if (bi_rdev && blk_integrity_compare(mddev->gendisk,
+					     rdev->bdev->bd_disk) >= 0)
+		return;
+	printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
+	blk_integrity_unregister(mddev->gendisk);
+}
+EXPORT_SYMBOL(md_integrity_add_rdev);
 
 static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 {
···
 	/* May as well allow recovery to be retried once */
 	mddev->recovery_disabled = 0;
 
-	md_integrity_check(rdev, mddev);
 	return 0;
 
  fail:
···
 		mddev->new_level = pers->level;
 	}
 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
-
-	if (pers->level >= 4 && pers->level <= 6)
-		/* Cannot support integrity (yet) */
-		blk_integrity_unregister(mddev->gendisk);
 
 	if (mddev->reshape_position != MaxSector &&
 	    pers->start_reshape == NULL) {

drivers/md/md.h

···
 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
 extern int md_check_no_bitmap(mddev_t *mddev);
+extern int md_integrity_register(mddev_t *mddev);
+void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
 
 #endif /* _MD_MD_H */

drivers/md/multipath.c

···
 			set_bit(In_sync, &rdev->flags);
 			rcu_assign_pointer(p->rdev, rdev);
 			err = 0;
+			md_integrity_add_rdev(rdev, mddev);
 			break;
 		}
 
···
 			/* lost the race, try later */
 			err = -EBUSY;
 			p->rdev = rdev;
+			goto abort;
 		}
+		md_integrity_register(mddev);
 	}
 abort:
 
···
 	mddev->queue->unplug_fn = multipath_unplug;
 	mddev->queue->backing_dev_info.congested_fn = multipath_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
-
+	md_integrity_register(mddev);
 	return 0;
 
 out_free_conf:

drivers/md/raid0.c

···
 
 	blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
 	dump_zones(mddev);
+	md_integrity_register(mddev);
 	return 0;
 }
 

drivers/md/raid1.c

···
 			rcu_assign_pointer(p->rdev, rdev);
 			break;
 		}
-
+	md_integrity_add_rdev(rdev, mddev);
 	print_conf(conf);
 	return err;
 }
···
 			/* lost the race, try later */
 			err = -EBUSY;
 			p->rdev = rdev;
+			goto abort;
 		}
+		md_integrity_register(mddev);
 	}
 abort:
 
···
 	mddev->queue->unplug_fn = raid1_unplug;
 	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
-
+	md_integrity_register(mddev);
 	return 0;
 
 out_no_mem:

drivers/md/raid10.c

···
 			break;
 		}
 
+	md_integrity_add_rdev(rdev, mddev);
 	print_conf(conf);
 	return err;
 }
···
 			/* lost the race, try later */
 			err = -EBUSY;
 			p->rdev = rdev;
+			goto abort;
 		}
+		md_integrity_register(mddev);
 	}
 abort:
 
···
 
 	if (conf->near_copies < mddev->raid_disks)
 		blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
+	md_integrity_register(mddev);
 	return 0;
 
 out_free_conf: