+static void *raid0_takeover_raid5(mddev_t *mddev)
+{
+ mdk_rdev_t *rdev;
+ raid0_conf_t *priv_conf;
+
+ if (mddev->degraded != 1) {
+ printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
+ mdname(mddev),
+ mddev->degraded);
+ return ERR_PTR(-EINVAL);
+ }
+
+ list_for_each_entry(rdev, &mddev->disks, same_set) {
+ /* check slot number for a disk */
+ if (rdev->raid_disk == mddev->raid_disks-1) {
+ printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
+ mdname(mddev));
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
+ /* Set new parameters */
+ mddev->new_level = 0;
+ mddev->new_chunk_sectors = mddev->chunk_sectors;
+ mddev->raid_disks--;
+ mddev->delta_disks = -1;
+ /* make sure it will be not marked as dirty */
+ mddev->recovery_cp = MaxSector;
+
+ create_strip_zones(mddev, &priv_conf);
+ return priv_conf;
+}
+
+static void *raid0_takeover_raid10(mddev_t *mddev)
+{
+ raid0_conf_t *priv_conf;
+
+ /* Check layout:
+ * - far_copies must be 1
+ * - near_copies must be 2
+ * - disks number must be even
+ * - all mirrors must be already degraded
+ */
+ if (mddev->layout != ((1 << 8) + 2)) {
+ printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
+ mdname(mddev),
+ mddev->layout);
+ return ERR_PTR(-EINVAL);
+ }
+ if (mddev->raid_disks & 1) {
+ printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
+ mdname(mddev));
+ return ERR_PTR(-EINVAL);
+ }
+ if (mddev->degraded != (mddev->raid_disks>>1)) {
+ printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
+ mdname(mddev));
+ return ERR_PTR(-EINVAL);
+ }
+
+ /* Set new parameters */
+ mddev->new_level = 0;
+ mddev->new_chunk_sectors = mddev->chunk_sectors;
+ mddev->delta_disks = - mddev->raid_disks / 2;
+ mddev->raid_disks += mddev->delta_disks;
+ mddev->degraded = 0;
+ /* make sure it will be not marked as dirty */
+ mddev->recovery_cp = MaxSector;
+
+ create_strip_zones(mddev, &priv_conf);
+ priv_conf->scale_raid_disks = 2;
+ return priv_conf;
+}
+
+static void *raid0_takeover(mddev_t *mddev)
+{
+ /* raid0 can take over:
+ * raid5 - providing it is Raid4 layout and one disk is faulty
+ * raid10 - assuming we have all necessary active disks
+ */
+ if (mddev->level == 5) {
+ if (mddev->layout == ALGORITHM_PARITY_N)
+ return raid0_takeover_raid5(mddev);
+
+ printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
+ mdname(mddev), ALGORITHM_PARITY_N);
+ }
+
+ if (mddev->level == 10)
+ return raid0_takeover_raid10(mddev);
+
+ return ERR_PTR(-EINVAL);
+}
+
+static void raid0_quiesce(mddev_t *mddev, int state)
+{
+}
+