Btrfs: add generation field to file extent

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 4a0367d..09de270 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -32,6 +32,7 @@
 	btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
 	btrfs_set_file_extent_offset(item, 0);
 	btrfs_set_file_extent_num_blocks(item, ins.offset);
+	btrfs_set_file_extent_generation(item, trans->transid);
 	mark_buffer_dirty(path.nodes[0]);
 	*result = ins.objectid;
 	btrfs_release_path(root, &path);