files_struct fdtable struct file

https://elixir.bootlin.com/linux/v5.7/source/include/linux/fdtable.h#L48

struct files_struct {
  /*
   * read mostly part
   */
	atomic_t count;
	bool resize_in_progress;
	wait_queue_head_t resize_wait;

	struct fdtable __rcu *fdt;
	struct fdtable fdtab;
  /*
   * written part on a separate cache line in SMP
   */
	spinlock_t file_lock ____cacheline_aligned_in_smp;
	unsigned int next_fd;
	unsigned long close_on_exec_init[1];
	unsigned long open_fds_init[1];
	unsigned long full_fds_bits_init[1];
	struct file __rcu * fd_array[NR_OPEN_DEFAULT];
};

https://elixir.bootlin.com/linux/v5.7/source/include/linux/fdtable.h#L26

struct fdtable {
	unsigned int max_fds;
	struct file __rcu **fd;      /* current fd array */
	unsigned long *close_on_exec;
	unsigned long *open_fds;
	unsigned long *full_fds_bits;
	struct rcu_head rcu;
};

• Locking: https://elixir.bootlin.com/linux/v5.7/source/Documentation/filesystems/files.txt
• struct file