1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/md/persistent-data/dm-array.c b/drivers/md/persistent-data/dm-array.c
index af96e24ec328..1d75b1dc1e2e 100644
--- a/drivers/md/persistent-data/dm-array.c
+++ b/drivers/md/persistent-data/dm-array.c
@@ -317,8 +317,16 @@ static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
          * The shadow op will often be a noop.  Only insert if it really
          * copied data.
          */
-        if (dm_block_location(*block) != b)
+        if (dm_block_location(*block) != b) {
+                /*
+                 * dm_tm_shadow_block will have already decremented the old
+                 * block, but it is still referenced by the btree.  We
+                 * increment to stop the insert decrementing it below zero
+                 * when overwriting the old value.
+                 */
+                dm_tm_inc(info->btree_info.tm, b);
                 r = insert_ablock(info, index, *block, root);
+        }
 
         return r;
 }