md: range check slot number when manually adding a spare.

When adding a spare to an active array, we should check the slot
number, but allow it to be larger than raid_disks if a reshape
is being prepared.

Apply the same test when adding a device to an
array-under-construction.  It already had most of the test in place,
but not quite all.

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

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5e3714fecee9..665851308818 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2479,6 +2479,10 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                         if (rdev2->raid_disk == slot)
                                 return -EEXIST;
 
+                if (slot >= rdev->mddev->raid_disks &&
+                    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
+                        return -ENOSPC;
+
                 rdev->raid_disk = slot;
                 if (test_bit(In_sync, &rdev->flags))
                         rdev->saved_raid_disk = slot;
@@ -2496,7 +2500,8 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                         /* failure here is OK */;
                 /* don't wakeup anyone, leave that to userspace. */
         } else {
-                if (slot >= rdev->mddev->raid_disks)
+                if (slot >= rdev->mddev->raid_disks &&
+                    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
                         return -ENOSPC;
                 rdev->raid_disk = slot;
                 /* assume it is working */