584  * Return true if the ref was merged into an existing one (and therefore can be
627 	/* remove existing tail if its ref_mod is zero */  in insert_delayed_ref()
636  * existing and update must have the same bytenr
639 			 struct btrfs_delayed_ref_head *existing,  in update_existing_head_ref()  argument
647 	BUG_ON(existing->is_data != update->is_data);  in update_existing_head_ref()
649 	spin_lock(&existing->lock);  in update_existing_head_ref()
654 		 * with an existing head ref without  in update_existing_head_ref()
658 		existing->must_insert_reserved = update->must_insert_reserved;  in update_existing_head_ref()
664 		existing->num_bytes = update->num_bytes;  in update_existing_head_ref()
669 		if (!existing->extent_op) {  in update_existing_head_ref()
670 			existing->extent_op = update->extent_op;  in update_existing_head_ref()
673 				memcpy(&existing->extent_op->key,  in update_existing_head_ref()
676 				existing->extent_op->update_key = true;  in update_existing_head_ref()
679 				existing->extent_op->flags_to_set |=  in update_existing_head_ref()
681 				existing->extent_op->update_flags = true;  in update_existing_head_ref()
691 	old_ref_mod = existing->total_ref_mod;  in update_existing_head_ref()
692 	existing->ref_mod += update->ref_mod;  in update_existing_head_ref()
693 	existing->total_ref_mod += update->ref_mod;  in update_existing_head_ref()
699 	if (existing->is_data) {  in update_existing_head_ref()
702 						   existing->num_bytes);  in update_existing_head_ref()
704 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {  in update_existing_head_ref()
705 			delayed_refs->pending_csums -= existing->num_bytes;  in update_existing_head_ref()
708 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {  in update_existing_head_ref()
709 			delayed_refs->pending_csums += existing->num_bytes;  in update_existing_head_ref()
714 	spin_unlock(&existing->lock);  in update_existing_head_ref()
794 	struct btrfs_delayed_ref_head *existing;  in add_delayed_ref_head()  local
811 	existing = htree_insert(&delayed_refs->href_root,  in add_delayed_ref_head()
813 	if (existing) {  in add_delayed_ref_head()
814 		update_existing_head_ref(trans, existing, head_ref);  in add_delayed_ref_head()
816 		 * we've updated the existing ref, free the newly  in add_delayed_ref_head()
820 		head_ref = existing;  in add_delayed_ref_head()