md/raid5: handle manually-added spares in start_reshape.

It is possible to manually add spares to specific slots before
starting a reshape.
raid5_start_reshape should recognised this possibility and include
it in the accounting.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d223a6c..5044bab 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5527,8 +5527,8 @@ static int raid5_start_reshape(mddev_t *mddev)
                return -ENOSPC;
 
        list_for_each_entry(rdev, &mddev->disks, same_set)
-               if (rdev->raid_disk < 0 &&
-                   !test_bit(Faulty, &rdev->flags))
+               if ((rdev->raid_disk < 0 || rdev->raid_disk >= conf->raid_disks)
+                    && !test_bit(Faulty, &rdev->flags))
                        spares++;
 
        if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
@@ -5588,6 +5588,11 @@ static int raid5_start_reshape(mddev_t *mddev)
                                        /* Failure here is OK */;
                        } else
                                break;
+               } else if (rdev->raid_disk >= conf->previous_raid_disks
+                          && !test_bit(Faulty, &rdev->flags)) {
+                       /* This is a spare that was manually added */
+                       set_bit(In_sync, &rdev->flags);
+                       added_devices++;
                }
 
        /* When a reshape changes the number of devices, ->degraded