nfs4_file_operations

https://elixir.bootlin.com/linux/v5.7/source/fs/nfs/nfs4file.c#L408

const struct file_operations nfs4_file_operations = {
	.read_iter	= nfs_file_read,
	.write_iter	= nfs_file_write,
	.mmap		= nfs_file_mmap,
	.open		= nfs4_file_open,
	.flush		= nfs4_file_flush,
	.release	= nfs_file_release,
	.fsync		= nfs_file_fsync,
	.lock		= nfs_lock,
	.flock		= nfs_flock,
	.splice_read	= generic_file_splice_read,
	.splice_write	= iter_file_splice_write,
	.check_flags	= nfs_check_flags,
	.setlease	= simple_nosetlease,
#ifdef CONFIG_NFS_V4_2
	.copy_file_range = nfs4_copy_file_range,
	.llseek		= nfs4_file_llseek,
	.fallocate	= nfs42_fallocate,
	.remap_file_range = nfs42_remap_file_range,
#else
	.llseek		= nfs_file_llseek,
#endif
};