438 	/* remove existing tail if its ref_mod is zero */  in insert_delayed_ref()
453  * existing and update must have the same bytenr
457 			 struct btrfs_delayed_ref_head *existing,  in update_existing_head_ref()  argument
463 	BUG_ON(existing->is_data != update->is_data);  in update_existing_head_ref()
465 	spin_lock(&existing->lock);  in update_existing_head_ref()
470 		 * with an existing head ref without  in update_existing_head_ref()
474 		existing->must_insert_reserved = update->must_insert_reserved;  in update_existing_head_ref()
480 		existing->num_bytes = update->num_bytes;  in update_existing_head_ref()
485 		if (!existing->extent_op) {  in update_existing_head_ref()
486 			existing->extent_op = update->extent_op;  in update_existing_head_ref()
489 				memcpy(&existing->extent_op->key,  in update_existing_head_ref()
492 				existing->extent_op->update_key = true;  in update_existing_head_ref()
495 				existing->extent_op->flags_to_set |=  in update_existing_head_ref()
497 				existing->extent_op->update_flags = true;  in update_existing_head_ref()
507 	old_ref_mod = existing->total_ref_mod;  in update_existing_head_ref()
510 	existing->ref_mod += update->ref_mod;  in update_existing_head_ref()
511 	existing->total_ref_mod += update->ref_mod;  in update_existing_head_ref()
517 	if (existing->is_data) {  in update_existing_head_ref()
518 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0)  in update_existing_head_ref()
519 			delayed_refs->pending_csums -= existing->num_bytes;  in update_existing_head_ref()
520 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0)  in update_existing_head_ref()
521 			delayed_refs->pending_csums += existing->num_bytes;  in update_existing_head_ref()
523 	spin_unlock(&existing->lock);  in update_existing_head_ref()
603 	struct btrfs_delayed_ref_head *existing;  in add_delayed_ref_head()  local
620 	existing = htree_insert(&delayed_refs->href_root,  in add_delayed_ref_head()
622 	if (existing) {  in add_delayed_ref_head()
625 			&& existing->qgroup_ref_root  in add_delayed_ref_head()
626 			&& existing->qgroup_reserved);  in add_delayed_ref_head()
627 		update_existing_head_ref(delayed_refs, existing, head_ref,  in add_delayed_ref_head()
630 		 * we've updated the existing ref, free the newly  in add_delayed_ref_head()
634 		head_ref = existing;  in add_delayed_ref_head()