I just noticed this RFC series in the nfs testing tree. Given that is not in linux-next I guess it really just is for testing, but if you are interestested in RWF_DONTCACHE support for NFS, please integrated with the series at: https://lore.kernel.org/linux-fsdevel/20250710101404.362146-1-chentaotao@xxxxxxxxxxxxxx/#r That adds full dontcache support for the write_begin based file systems.
