+ } else if (cmd_match(buf, "want_replacement")) {
+ /* Any non-spare device that is not a replacement can
+ * become want_replacement at any time, but we then need to
+ * check if recovery is needed.
+ */
+ if (rdev->raid_disk >= 0 &&
+ !test_bit(Replacement, &rdev->flags))
+ set_bit(WantReplacement, &rdev->flags);
+ set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
+ md_wakeup_thread(rdev->mddev->thread);
+ err = 0;
+ } else if (cmd_match(buf, "-want_replacement")) {
+ /* Clearing 'want_replacement' is always allowed.
+ * Once replacements starts it is too late though.
+ */
+ err = 0;
+ clear_bit(WantReplacement, &rdev->flags);
+ } else if (cmd_match(buf, "replacement")) {
+ /* Can only set a device as a replacement when array has not
+ * yet been started. Once running, replacement is automatic
+ * from spares, or by assigning 'slot'.
+ */
+ if (rdev->mddev->pers)
+ err = -EBUSY;
+ else {
+ set_bit(Replacement, &rdev->flags);
+ err = 0;
+ }
+ } else if (cmd_match(buf, "-replacement")) {
+ /* Similarly, can only clear Replacement before start */
+ if (rdev->mddev->pers)
+ err = -EBUSY;
+ else {
+ clear_bit(Replacement, &rdev->flags);
+ err = 0;
+ }