http://fxr.watson.org/fxr/source/include/linux/fs.h?v=linux-2.4.22#L563
struct file {564 struct list_head f_list;565 struct dentry *f_dentry;566 struct vfsmount *f_vfsmnt;567 struct file_operations *f_op;568 atomic_t f_count;569 unsigned int f_flags;570 mode_t f_mode;571 loff_t f_pos;572 unsigned long f_reada, f_ramax, f_raend, f_ralen, f_rawin;573 struct fown_struct f_owner;574 unsigned int f_uid, f_gid;575 int f_error;576 577 unsigned long f_version;578 579 /* needed for tty driver, and maybe others */580 void *private_data;581 582 /* preallocated helper kiobuf to speedup O_DIRECT */583 struct kiobuf *f_iobuf;584 long f_iobuf_lock;585 };