632 	/* remove existing tail if its ref_mod is zero */  in insert_delayed_ref()
647  * existing and update must have the same bytenr
650 			 struct btrfs_delayed_ref_head *existing,  in update_existing_head_ref()  argument
659 	BUG_ON(existing->is_data != update->is_data);  in update_existing_head_ref()
661 	spin_lock(&existing->lock);  in update_existing_head_ref()
666 		 * with an existing head ref without  in update_existing_head_ref()
670 		existing->must_insert_reserved = update->must_insert_reserved;  in update_existing_head_ref()
676 		existing->num_bytes = update->num_bytes;  in update_existing_head_ref()
681 		if (!existing->extent_op) {  in update_existing_head_ref()
682 			existing->extent_op = update->extent_op;  in update_existing_head_ref()
685 				memcpy(&existing->extent_op->key,  in update_existing_head_ref()
688 				existing->extent_op->update_key = true;  in update_existing_head_ref()
691 				existing->extent_op->flags_to_set |=  in update_existing_head_ref()
693 				existing->extent_op->update_flags = true;  in update_existing_head_ref()
703 	old_ref_mod = existing->total_ref_mod;  in update_existing_head_ref()
706 	existing->ref_mod += update->ref_mod;  in update_existing_head_ref()
707 	existing->total_ref_mod += update->ref_mod;  in update_existing_head_ref()
713 	if (existing->is_data) {  in update_existing_head_ref()
716 						   existing->num_bytes);  in update_existing_head_ref()
718 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {  in update_existing_head_ref()
719 			delayed_refs->pending_csums -= existing->num_bytes;  in update_existing_head_ref()
722 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {  in update_existing_head_ref()
723 			delayed_refs->pending_csums += existing->num_bytes;  in update_existing_head_ref()
727 	spin_unlock(&existing->lock);  in update_existing_head_ref()
804 	struct btrfs_delayed_ref_head *existing;  in add_delayed_ref_head()  local
821 	existing = htree_insert(&delayed_refs->href_root,  in add_delayed_ref_head()
823 	if (existing) {  in add_delayed_ref_head()
824 		update_existing_head_ref(trans, existing, head_ref,  in add_delayed_ref_head()
827 		 * we've updated the existing ref, free the newly  in add_delayed_ref_head()
831 		head_ref = existing;  in add_delayed_ref_head()