Btrfs: smarter transaction writeback

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index afc5267..652cf30 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -762,6 +762,7 @@
 	BUG_ON(ret);
 	buf = btrfs_find_create_tree_block(root, ins.objectid);
 	set_buffer_uptodate(buf);
+	set_radix_bit(&trans->transaction->dirty_pages, buf->b_page->index);
 	return buf;
 }