+
+static void *raid5_takeover_raid1(mddev_t *mddev)
+{
+ int chunksect;
+
+ if (mddev->raid_disks != 2 ||
+ mddev->degraded > 1)
+ return ERR_PTR(-EINVAL);
+
+ /* Should check if there are write-behind devices? */
+
+ chunksect = 64*2; /* 64K by default */
+
+ /* The array must be an exact multiple of chunksize */
+ while (chunksect && (mddev->array_sectors & (chunksect-1)))
+ chunksect >>= 1;
+
+ if ((chunksect<<9) < STRIPE_SIZE)
+ /* array size does not allow a suitable chunk size */
+ return ERR_PTR(-EINVAL);
+
+ mddev->new_level = 5;
+ mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
+ mddev->new_chunk = chunksect << 9;
+
+ return setup_conf(mddev);
+}
+
+static void *raid5_takeover_raid6(mddev_t *mddev)
+{
+ int new_layout;
+
+ switch (mddev->layout) {
+ case ALGORITHM_LEFT_ASYMMETRIC_6:
+ new_layout = ALGORITHM_LEFT_ASYMMETRIC;
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC_6:
+ new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC_6:
+ new_layout = ALGORITHM_LEFT_SYMMETRIC;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC_6:
+ new_layout = ALGORITHM_RIGHT_SYMMETRIC;
+ break;
+ case ALGORITHM_PARITY_0_6:
+ new_layout = ALGORITHM_PARITY_0;
+ break;
+ case ALGORITHM_PARITY_N:
+ new_layout = ALGORITHM_PARITY_N;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+ mddev->new_level = 5;
+ mddev->new_layout = new_layout;
+ mddev->delta_disks = -1;
+ mddev->raid_disks -= 1;
+ return setup_conf(mddev);
+}
+
+
+static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
+{
+ /* For a 2-drive array, the layout and chunk size can be changed
+ * immediately as not restriping is needed.
+ * For larger arrays we record the new value - after validation
+ * to be used by a reshape pass.
+ */
+ raid5_conf_t *conf = mddev_to_conf(mddev);
+
+ if (new_layout >= 0 && !algorithm_valid_raid5(new_layout))
+ return -EINVAL;
+ if (new_chunk > 0) {
+ if (new_chunk & (new_chunk-1))
+ /* not a power of 2 */
+ return -EINVAL;
+ if (new_chunk < PAGE_SIZE)
+ return -EINVAL;
+ if (mddev->array_sectors & ((new_chunk>>9)-1))
+ /* not factor of array size */
+ return -EINVAL;
+ }
+
+ /* They look valid */
+
+ if (mddev->raid_disks == 2) {
+
+ if (new_layout >= 0) {
+ conf->algorithm = new_layout;
+ mddev->layout = mddev->new_layout = new_layout;
+ }
+ if (new_chunk > 0) {
+ conf->chunk_size = new_chunk;
+ mddev->chunk_size = mddev->new_chunk = new_chunk;
+ }
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ md_wakeup_thread(mddev->thread);
+ } else {
+ if (new_layout >= 0)
+ mddev->new_layout = new_layout;
+ if (new_chunk > 0)
+ mddev->new_chunk = new_chunk;
+ }
+ return 0;
+}
+
+static int raid6_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
+{
+ if (new_layout >= 0 && !algorithm_valid_raid6(new_layout))
+ return -EINVAL;
+ if (new_chunk > 0) {
+ if (new_chunk & (new_chunk-1))
+ /* not a power of 2 */
+ return -EINVAL;
+ if (new_chunk < PAGE_SIZE)
+ return -EINVAL;
+ if (mddev->array_sectors & ((new_chunk>>9)-1))
+ /* not factor of array size */
+ return -EINVAL;
+ }
+
+ /* They look valid */
+
+ if (new_layout >= 0)
+ mddev->new_layout = new_layout;
+ if (new_chunk > 0)
+ mddev->new_chunk = new_chunk;
+
+ return 0;
+}
+
+static void *raid5_takeover(mddev_t *mddev)
+{
+ /* raid5 can take over:
+ * raid0 - if all devices are the same - make it a raid4 layout
+ * raid1 - if there are two drives. We need to know the chunk size
+ * raid4 - trivial - just use a raid4 layout.
+ * raid6 - Providing it is a *_6 layout
+ *
+ * For now, just do raid1
+ */
+
+ if (mddev->level == 1)
+ return raid5_takeover_raid1(mddev);
+ if (mddev->level == 4) {
+ mddev->new_layout = ALGORITHM_PARITY_N;
+ mddev->new_level = 5;
+ return setup_conf(mddev);
+ }
+ if (mddev->level == 6)
+ return raid5_takeover_raid6(mddev);
+
+ return ERR_PTR(-EINVAL);
+}
+
+
+static struct mdk_personality raid5_personality;
+
+static void *raid6_takeover(mddev_t *mddev)
+{
+ /* Currently can only take over a raid5. We map the
+ * personality to an equivalent raid6 personality
+ * with the Q block at the end.
+ */
+ int new_layout;
+
+ if (mddev->pers != &raid5_personality)
+ return ERR_PTR(-EINVAL);
+ if (mddev->degraded > 1)
+ return ERR_PTR(-EINVAL);
+ if (mddev->raid_disks > 253)
+ return ERR_PTR(-EINVAL);
+ if (mddev->raid_disks < 3)
+ return ERR_PTR(-EINVAL);
+
+ switch (mddev->layout) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC:
+ new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
+ break;
+ case ALGORITHM_PARITY_0:
+ new_layout = ALGORITHM_PARITY_0_6;
+ break;
+ case ALGORITHM_PARITY_N:
+ new_layout = ALGORITHM_PARITY_N;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+ mddev->new_level = 6;
+ mddev->new_layout = new_layout;
+ mddev->delta_disks = 1;
+ mddev->raid_disks += 1;
+ return setup_conf(mddev);
+}
+
+