fs/btrfs/delayed-ref.c

658  * Return true if the ref was merged into an existing one (and therefore can be
703 	/* remove existing tail if its ref_mod is zero */
712  * existing and update must have the same bytenr
715 			 struct btrfs_delayed_ref_head *existing,
723 	BUG_ON(existing->is_data != update->is_data);
725 	spin_lock(&existing->lock);
732 	if (!existing->owning_root)
733 		existing->owning_root = update->owning_root;
739 		 * with an existing head ref without
743 		existing->must_insert_reserved = update->must_insert_reserved;
744 		existing->owning_root = update->owning_root;
750 		existing->num_bytes = update->num_bytes;
755 		if (!existing->extent_op) {
756 			existing->extent_op = update->extent_op;
759 				memcpy(&existing->extent_op->key,
762 				existing->extent_op->update_key = true;
765 				existing->extent_op->flags_to_set |=
767 				existing->extent_op->update_flags = true;
777 	old_ref_mod = existing->total_ref_mod;
778 	existing->ref_mod += update->ref_mod;
779 	existing->total_ref_mod += update->ref_mod;
787 	if (existing->is_data) {
790 						   existing->num_bytes);
792 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {
793 			delayed_refs->pending_csums -= existing->num_bytes;
796 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {
797 			delayed_refs->pending_csums += existing->num_bytes;
802 	spin_unlock(&existing->lock);
886 	struct btrfs_delayed_ref_head *existing;
903 	existing = htree_insert(&delayed_refs->href_root,
905 	if (existing) {
906 		update_existing_head_ref(trans, existing, head_ref);
908 		 * we've updated the existing ref, free the newly
912 		head_ref = existing;