Linux的file结构体和inode结构体怎么用

struct file {
        union {
           struct llist_node         fu_llist;
           struct rcu_head          fu_rcuhead;
        } 
        f_u;
        struct path               f_path;
        struct inode              *f_inode;/* cached value */
        const struct file_operations      *f_op;/* 和文件关联的操作 */
        /*
         * Protects f_ep_links, f_flags.
         * Must not be taken from IRQ context.
         */
        spinlock_t                f_lock;
        enum rw_hint              f_write_hint;
        atomic_long_t              f_count;
        unsigned int              f_flags;/* 文件标志，如O_RDONLY、O_NONBLOCK、O_SYNC */
        fmode_t                 f_mode;/* 文件读/写模式，FMODE_READ、FMODE_WRITE */
        struct mutex              f_pos_lock;
        loff_t                  f_pos;/* 当前读写位置 */
        struct fown_struct        f_owner;
        const struct cred        *f_cred;
        struct file_ra_state        f_ra;
        u64                f_version;

        #ifdef CONFIG_SECURITY
        void *f_security;
        #endif
        /* needed for tty driver, and maybe others */
        void *private_data; /* 文件私有数据 */
        #ifdef CONFIG_EPOLL
        /* Used by fs/eventpoll.c to link all the hooks to this file */
        struct list_head f_ep_links;
        struct list_head f_tfile_llink;
        #endif /* #ifdef CONFIG_EPOLL */
        struct address_space *f_mapping;
        errseq_t f_wb_err;
    }
    __randomize_layout
  __attribute__((aligned(4)));/* lest something weird decides that 2 is OK */
  
    struct file_handle {
      __u32 handle_bytes;
      int handle_type;
      /* file identifier */
      unsigned char f_handle[0];
    };

struct inode {        umode_t                        i_mode;	/* inode的权限 */        unsigned short                i_opflags;        kuid_t                        i_uid;	/* inode拥有者的id */        kgid_t                        i_gid;	/* inode所属的群组id */        unsigned int                i_flags;#ifdef CONFIG_FS_POSIX_ACL        struct posix_acl        *i_acl;        struct posix_acl        *i_default_acl;#endif        const struct inode_operations        *i_op;        struct super_block        *i_sb;        struct address_space        *i_mapping;#ifdef CONFIG_SECURITY        void                        *i_security;#endif        /* Stat data, not accessed from path walking */        unsigned long                i_ino;        /*         * Filesystems may only read i_nlink directly.  They shall use the         * following functions for modification:         *         *    (set|clear|inc|drop)_nlink         *    inode_(inc|dec)_link_count         */        union {                const unsigned int i_nlink;                unsigned int __i_nlink;        };        dev_t                        i_rdev;	/* 若是设备文件，此字段将记录设备的设备号 */        loff_t                        i_size;	/* inode所代表的文件大小 */        struct timespec                i_atime;	/* inode最近一次的存取时间 */        struct timespec                i_mtime;	/* inode最近一次的修改时间 */        struct timespec                i_ctime;	/* inode的产生时间 */        spinlock_t                i_lock;	/* i_blocks, i_bytes, maybe i_size */        unsigned short          i_bytes;        unsigned int                i_blkbits;        enum rw_hint                i_write_hint;        blkcnt_t                i_blocks;	/* inode所使用的block数，一个block为512字节 */#ifdef __NEED_I_SIZE_ORDERED        seqcount_t                i_size_seqcount;#endif        /* Misc */        unsigned long                i_state;        struct rw_semaphore        i_rwsem;        unsigned long                dirtied_when;	/* jiffies of first dirtying */        unsigned long                dirtied_time_when;        struct hlist_node        i_hash;        struct list_head        i_io_list;	/* backing dev IO list */#ifdef CONFIG_CGROUP_WRITEBACK        struct bdi_writeback        *i_wb;	/* the associated cgroup wb */        /* foreign inode detection, see wbc_detach_inode() */        int                        i_wb_frn_winner;        u16                        i_wb_frn_avg_time;        u16                        i_wb_frn_history;#endif        struct list_head        i_lru;	/* inode LRU list */        struct list_head        i_sb_list;        struct list_head        i_wb_list; 	/* backing dev writeback list */        union {                struct hlist_head        i_dentry;                struct rcu_head                i_rcu;        };        u64                        i_version;        atomic_t                i_count;        atomic_t                i_dio_count;        atomic_t                i_writecount;#ifdef CONFIG_IMA        atomic_t                i_readcount;	/* struct files open RO */#endif        const struct file_operations        *i_fop;	/* former ->i_op->default_file_ops */        struct file_lock_context        *i_flctx;        struct address_space        i_data;        struct list_head        i_devices;        union {                struct pipe_inode_info        *i_pipe;                struct block_device        *i_bdev;		/* 若是块设备，为其对应的block_device结构体指针 */                struct cdev                *i_cdev;		/* 若是字符设备，为其对应的cdev结构体指针 */                char                        *i_link;                unsigned                i_dir_seq;        };        __u32                        i_generation;#ifdef CONFIG_FSNOTIFY        __u32                        i_fsnotify_mask;	/* all events this inode cares about */        struct fsnotify_mark_connector __rcu        *i_fsnotify_marks;#endif#if IS_ENABLED(CONFIG_FS_ENCRYPTION)        struct fscrypt_info        *i_crypt_info;#endif        void                        *i_private;	/* fs or device private pointer */} __randomize_layout;