Call btrfs_cow_block while lowering tree level.
When freeing root block of a tree, btrfs_free_extent' parameter
'ref_generation' is from root block itseft. When freeing non-root
block, 'ref_generation' is from its parent. so when converting a
non-root block to root block, we must guarantee its generation is
equal to its parent's generation.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index cf32651..ef8809c 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -720,6 +720,9 @@
/* promote the child to a root */
child = read_node_slot(root, mid, 0);
BUG_ON(!child);
+ ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
+ BUG_ON(ret);
+
root->node = child;
path->nodes[level] = NULL;
clean_tree_block(trans, root, mid);