md: fix some bugs with growing raid5/raid6 arrays.

The recent changed to raid5 to allow offload of parity calculation etc
introduced some bugs in the code for growing (i.e.  adding a disk to) raid5
and raid6.  This fixes them

Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 8 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 2aff4be35dc4..4d63773ee73a 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2541,7 +2541,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
         struct dma_async_tx_descriptor *tx = NULL;
         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
         for (i = 0; i < sh->disks; i++)
-                if (i != sh->pd_idx && (r6s && i != r6s->qd_idx)) {
+                if (i != sh->pd_idx && (!r6s || i != r6s->qd_idx)) {
                         int dd_idx, pd_idx, j;
                         struct stripe_head *sh2;
 
@@ -2574,7 +2574,8 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
                         for (j = 0; j < conf->raid_disks; j++)
                                 if (j != sh2->pd_idx &&
-                                    (r6s && j != r6s->qd_idx) &&
+                                    (!r6s || j != raid6_next_disk(sh2->pd_idx,
+                                                                 sh2->disks)) &&
                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
                                         break;
                         if (j == conf->raid_disks) {
@@ -2583,12 +2584,12 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
                         }
                         release_stripe(sh2);
 
-                        /* done submitting copies, wait for them to complete */
-                        if (i + 1 >= sh->disks) {
-                                async_tx_ack(tx);
-                                dma_wait_for_async_tx(tx);
-                        }
                 }
+        /* done submitting copies, wait for them to complete */
+        if (tx) {
+                async_tx_ack(tx);
+                dma_wait_for_async_tx(tx);
+        }
 }
 
 /*
@@ -2855,7 +2856,7 @@ static void handle_stripe5(struct stripe_head *sh)
                 sh->disks = conf->raid_disks;
                 sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
                         conf->raid_disks);
-                s.locked += handle_write_operations5(sh, 0, 1);
+                s.locked += handle_write_operations5(sh, 1, 1);
         } else if (s.expanded &&
                 !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
                 clear_bit(STRIPE_EXPAND_READY, &sh->state);