I suggest to create a new function GinPredicateLockPage() that checks whether fast update is enabled for the index. The current arrangement looks too repetitive and it seems easy to make a mistake.
Stylistically, please keep #include lines ordered alphabetically, and cut long lines to below 80 chars. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services