fs/btrfs/delayed-ref.c

683  * Return true if the ref was merged into an existing one (and therefore can be
728 	/* remove existing tail if its ref_mod is zero */
737  * existing and update must have the same bytenr
740 			 struct btrfs_delayed_ref_head *existing,
748 	BUG_ON(existing->is_data != update->is_data);
750 	spin_lock(&existing->lock);
757 	if (!existing->owning_root)
758 		existing->owning_root = update->owning_root;
764 		 * with an existing head ref without
768 		existing->must_insert_reserved = update->must_insert_reserved;
769 		existing->owning_root = update->owning_root;
775 		existing->num_bytes = update->num_bytes;
780 		if (!existing->extent_op) {
781 			existing->extent_op = update->extent_op;
784 				memcpy(&existing->extent_op->key,
787 				existing->extent_op->update_key = true;
790 				existing->extent_op->flags_to_set |=
792 				existing->extent_op->update_flags = true;
802 	old_ref_mod = existing->total_ref_mod;
803 	existing->ref_mod += update->ref_mod;
804 	existing->total_ref_mod += update->ref_mod;
812 	if (existing->is_data) {
815 						   existing->num_bytes);
817 		if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {
818 			delayed_refs->pending_csums -= existing->num_bytes;
821 		if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {
822 			delayed_refs->pending_csums += existing->num_bytes;
827 	spin_unlock(&existing->lock);
909 	struct btrfs_delayed_ref_head *existing;
926 	existing = htree_insert(&delayed_refs->href_root,
928 	if (existing) {
929 		update_existing_head_ref(trans, existing, head_ref);
931 		 * we've updated the existing ref, free the newly
935 		head_ref = existing;