1 files changed, 5 insertions, 2 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b904c74f31fd..3b327c8cfb16 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10547,10 +10547,13 @@ static const struct file_operations btrfs_dir_file_operations = {
 };
 
 static const struct extent_io_ops btrfs_extent_io_ops = {
-        .fill_delalloc = run_delalloc_range,
+        /* mandatory callbacks */
         .submit_bio_hook = btrfs_submit_bio_hook,
-        .merge_bio_hook = btrfs_merge_bio_hook,
         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
+        .merge_bio_hook = btrfs_merge_bio_hook,
+
+        /* optional callbacks */
+        .fill_delalloc = run_delalloc_range,
         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
         .writepage_start_hook = btrfs_writepage_start_hook,
         .set_bit_hook = btrfs_set_bit_hook,