md: fix problems with RAID6 calculations for DDF.

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

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 25c3c29..d4ce51b 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -158,11 +158,14 @@ static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 {
        int slot;
 
+       if (sh->ddf_layout)
+               slot = (*count)++;
        if (idx == sh->pd_idx)
                return syndrome_disks;
        if (idx == sh->qd_idx)
                return syndrome_disks + 1;
-       slot = (*count)++;
+       if (!sh->ddf_layout)
+               slot = (*count)++;
        return slot;
 }
 
@@ -727,9 +730,8 @@ static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
                srcs[slot] = sh->dev[i].page;
                i = raid6_next_disk(i, disks);
        } while (i != d0_idx);
-       BUG_ON(count != syndrome_disks);
 
-       return count;
+       return syndrome_disks;
 }
 
 static struct dma_async_tx_descriptor *
@@ -828,7 +830,6 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
                        failb = slot;
                i = raid6_next_disk(i, disks);
        } while (i != d0_idx);
-       BUG_ON(count != syndrome_disks);
 
        BUG_ON(faila == failb);
        if (failb < faila)
@@ -845,7 +846,7 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
                        init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
                                          ops_complete_compute, sh,
                                          to_addr_conv(sh, percpu));
-                       return async_gen_syndrome(blocks, 0, count+2,
+                       return async_gen_syndrome(blocks, 0, syndrome_disks+2,
                                                  STRIPE_SIZE, &submit);
                } else {
                        struct page *dest;
@@ -1935,10 +1936,15 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
                case ALGORITHM_PARITY_N:
                        break;
                case ALGORITHM_ROTATING_N_CONTINUE:
+                       /* Like left_symmetric, but P is before Q */
                        if (sh->pd_idx == 0)
                                i--;    /* P D D D Q */
-                       else if (i > sh->pd_idx)
-                               i -= 2; /* D D Q P D */
+                       else {
+                               /* D D Q P D */
+                               if (i < sh->pd_idx)
+                                       i += raid_disks;
+                               i -= (sh->pd_idx + 1);
+                       }
                        break;
                case ALGORITHM_LEFT_ASYMMETRIC_6:
                case ALGORITHM_RIGHT_ASYMMETRIC_6:

diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index dcefdc9..dd70835 100644 (file)
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -488,7 +488,7 @@ static inline int algorithm_valid_raid6(int layout)
 {
        return (layout >= 0 && layout <= 5)
                ||
-               (layout == 8 || layout == 10)
+               (layout >= 8 && layout <= 10)
                ||
                (layout >= 16 && layout <= 20);
 }