1 files changed, 47 insertions, 2 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4fdc6d02b44..062df846fd6 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -395,7 +395,8 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector,
                                 init_stripe(sh, sector, previous);
                 } else {
                         if (atomic_read(&sh->count)) {
-                          BUG_ON(!list_empty(&sh->lru));
+                                BUG_ON(!list_empty(&sh->lru)
+                                    && !test_bit(STRIPE_EXPANDING, &sh->state));
                         } else {
                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
                                         atomic_inc(&conf->active_stripes);
@@ -2944,6 +2945,23 @@ static bool handle_stripe5(struct stripe_head *sh)
 
         /* Finish reconstruct operations initiated by the expansion process */
         if (sh->reconstruct_state == reconstruct_state_result) {
+                struct stripe_head *sh2
+                        = get_active_stripe(conf, sh->sector, 1, 1);
+                if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
+                        /* sh cannot be written until sh2 has been read.
+                         * so arrange for sh to be delayed a little
+                         */
+                        set_bit(STRIPE_DELAYED, &sh->state);
+                        set_bit(STRIPE_HANDLE, &sh->state);
+                        if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
+                                              &sh2->state))
+                                atomic_inc(&conf->preread_active_stripes);
+                        release_stripe(sh2);
+                        goto unlock;
+                }
+                if (sh2)
+                        release_stripe(sh2);
+
                 sh->reconstruct_state = reconstruct_state_idle;
                 clear_bit(STRIPE_EXPANDING, &sh->state);
                 for (i = conf->raid_disks; i--; ) {
@@ -3172,6 +3190,23 @@ static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
                 }
 
         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
+                struct stripe_head *sh2
+                        = get_active_stripe(conf, sh->sector, 1, 1);
+                if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
+                        /* sh cannot be written until sh2 has been read.
+                         * so arrange for sh to be delayed a little
+                         */
+                        set_bit(STRIPE_DELAYED, &sh->state);
+                        set_bit(STRIPE_HANDLE, &sh->state);
+                        if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
+                                              &sh2->state))
+                                atomic_inc(&conf->preread_active_stripes);
+                        release_stripe(sh2);
+                        goto unlock;
+                }
+                if (sh2)
+                        release_stripe(sh2);
+
                 /* Need to write out all blocks after computing P&Q */
                 sh->disks = conf->raid_disks;
                 stripe_set_idx(sh->sector, conf, 0, sh);
@@ -3739,6 +3774,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
         sector_t writepos, safepos, gap;
         sector_t stripe_addr;
         int reshape_sectors;
+        struct list_head stripes;
 
         if (sector_nr == 0) {
                 /* If restarting in the middle, skip the initial sectors */
@@ -3816,6 +3852,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
                 BUG_ON(writepos != sector_nr + reshape_sectors);
                 stripe_addr = sector_nr;
         }
+        INIT_LIST_HEAD(&stripes);
         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
                 int j;
                 int skipped = 0;
@@ -3845,7 +3882,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
                         set_bit(STRIPE_EXPAND_READY, &sh->state);
                         set_bit(STRIPE_HANDLE, &sh->state);
                 }
-                release_stripe(sh);
+                list_add(&sh->lru, &stripes);
         }
         spin_lock_irq(&conf->device_lock);
         if (mddev->delta_disks < 0)
@@ -3874,6 +3911,14 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
                 release_stripe(sh);
                 first_sector += STRIPE_SECTORS;
         }
+        /* Now that the sources are clearly marked, we can release
+         * the destination stripes
+         */
+        while (!list_empty(&stripes)) {
+                sh = list_entry(stripes.next, struct stripe_head, lru);
+                list_del_init(&sh->lru);
+                release_stripe(sh);
+        }
         /* If this takes us to the resync_max point where we have to pause,
          * then we need to write out the superblock.
          */