md: give userspace control over removing failed devices when external metdata in use

[net-next-2.6.git] / drivers / md / md.c

diff --git a/drivers/md/md.c b/drivers/md/md.c
index e2782a04012da1e2869a2351dcbb689d88537524..00788c56276ff1f5db5b2250faf0abeadabb16c1 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1891,20 +1891,44 @@ static ssize_t
 slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 {
        char *e;
+       int err;
+       char nm[20];
        int slot = simple_strtoul(buf, &e, 10);
        if (strncmp(buf, "none", 4)==0)
                slot = -1;
        else if (e==buf || (*e && *e!= '\n'))
                return -EINVAL;
-       if (rdev->mddev->pers)
-               /* Cannot set slot in active array (yet) */
-               return -EBUSY;
-       if (slot >= rdev->mddev->raid_disks)
-               return -ENOSPC;
-       rdev->raid_disk = slot;
-       /* assume it is working */
-       rdev->flags = 0;
-       set_bit(In_sync, &rdev->flags);
+       if (rdev->mddev->pers) {
+               /* Setting 'slot' on an active array requires also
+                * updating the 'rd%d' link, and communicating
+                * with the personality with ->hot_*_disk.
+                * For now we only support removing
+                * failed/spare devices.  This normally happens automatically,
+                * but not when the metadata is externally managed.
+                */
+               if (slot != -1)
+                       return -EBUSY;
+               if (rdev->raid_disk == -1)
+                       return -EEXIST;
+               /* personality does all needed checks */
+               if (rdev->mddev->pers->hot_add_disk == NULL)
+                       return -EINVAL;
+               err = rdev->mddev->pers->
+                       hot_remove_disk(rdev->mddev, rdev->raid_disk);
+               if (err)
+                       return err;
+               sprintf(nm, "rd%d", rdev->raid_disk);
+               sysfs_remove_link(&rdev->mddev->kobj, nm);
+               set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
+               md_wakeup_thread(rdev->mddev->thread);
+       } else {
+               if (slot >= rdev->mddev->raid_disks)
+                       return -ENOSPC;
+               rdev->raid_disk = slot;
+               /* assume it is working */
+               rdev->flags = 0;
+               set_bit(In_sync, &rdev->flags);
+       }
        return len;
 }
 
@@ -5549,6 +5573,7 @@ static int remove_and_add_spares(mddev_t *mddev)
 
        ITERATE_RDEV(mddev,rdev,rtmp)
                if (rdev->raid_disk >= 0 &&
+                   !mddev->external &&
                    (test_bit(Faulty, &rdev->flags) ||
                     ! test_bit(In_sync, &rdev->flags)) &&
                    atomic_read(&rdev->nr_pending)==0) {