620 	/* remove existing tail if its ref_mod is zero */  in insert_delayed_ref()
635  * existing and update must have the same bytenr
638 			 struct btrfs_delayed_ref_head *existing,  in update_existing_head_ref()  argument
646 	BUG_ON(existing->is_data != update->is_data);  in update_existing_head_ref()
648 	spin_lock(&existing->lock);  in update_existing_head_ref()
653 		 * with an existing head ref without  in update_existing_head_ref()
657 		existing->must_insert_reserved = update->must_insert_reserved;  in update_existing_head_ref()
663 		existing->num_bytes = update->num_bytes;  in update_existing_head_ref()
668 		if (!existing->extent_op) {  in update_existing_head_ref()
669 			existing->extent_op = update->extent_op;  in update_existing_head_ref()
672 				memcpy(&existing->extent_op->key,  in update_existing_head_ref()
675 				existing->extent_op->update_key = true;  in update_existing_head_ref()
678 				existing->extent_op->flags_to_set |=  in update_existing_head_ref()
680 				existing->extent_op->update_flags = true;  in update_existing_head_ref()
690 	old_ref_mod = existing->total_ref_mod;  in update_existing_head_ref()
691 	existing->ref_mod += update->ref_mod;  in update_existing_head_ref()
692 	existing->total_ref_mod += update->ref_mod;  in update_existing_head_ref()
698 	if (existing->is_data) {  in update_existing_head_ref()
701 						   existing->num_bytes);  in update_existing_head_ref()
703 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {  in update_existing_head_ref()
704 			delayed_refs->pending_csums -= existing->num_bytes;  in update_existing_head_ref()
707 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {  in update_existing_head_ref()
708 			delayed_refs->pending_csums += existing->num_bytes;  in update_existing_head_ref()
713 	spin_unlock(&existing->lock);  in update_existing_head_ref()
789 	struct btrfs_delayed_ref_head *existing;  in add_delayed_ref_head()  local
806 	existing = htree_insert(&delayed_refs->href_root,  in add_delayed_ref_head()
808 	if (existing) {  in add_delayed_ref_head()
809 		update_existing_head_ref(trans, existing, head_ref);  in add_delayed_ref_head()
811 		 * we've updated the existing ref, free the newly  in add_delayed_ref_head()
815 		head_ref = existing;  in add_delayed_ref_head()