/include/linux/fs.h

struct inode {

    struct hlist_node    i_hash;

    struct list_head    i_list;

    struct list_head    i_dentry;//All the dentrys which point to this inode list together.

    unsigned long        i_ino;//The inode id, unique in a certain fils system.Sometimes kernel use the i_ino to locate the inode structure

    atomic_t        i_count;

    umode_t            i_mode;

    unsigned int        i_nlink;//How many dentrys points to this same inode.

    uid_t            i_uid;

    gid_t            i_gid;

    dev_t            i_rdev;//if this inode standard for a specific device file, the region include major/minor device number.

    loff_t            i_size;//The size of the data in this inode.

    struct timespec        i_atime;

    struct timespec        i_mtime;

    struct timespec        i_ctime;

    unsigned int        i_blkbits;

    unsigned long        i_blksize;

    unsigned long        i_version;

    unsigned long        i_blocks;

    unsigned short          i_bytes;

    unsigned char        i_sock;

    spinlock_t        i_lock;    /* i_blocks, i_bytes, maybe i_size */

    struct semaphore    i_sem;

    struct rw_semaphore    i_alloc_sem;

    struct inode_operations    *i_op;

    struct file_operations    *i_fop;    /* former ->i_op->default_file_ops */

    struct super_block    *i_sb;

    struct file_lock    *i_flock;

    struct address_space    *i_mapping;

    struct address_space    i_data;

#ifdef CONFIG_QUOTA

    struct dquot        *i_dquot[MAXQUOTAS];

#endif

    /* These three should probably be a union */

    struct list_head    i_devices;

    struct pipe_inode_info    *i_pipe;

    struct block_device    *i_bdev;

    struct cdev        *i_cdev;

    int            i_cindex;

    __u32            i_generation;

#ifdef CONFIG_DNOTIFY

    unsigned long        i_dnotify_mask; /* Directory notify events */

    struct dnotify_struct    *i_dnotify; /* for directory notifications */

#endif

    unsigned long        i_state;

    unsigned long        dirtied_when;    /* jiffies of first dirtying */

    unsigned int        i_flags;

    atomic_t        i_writecount;

    void            *i_security;

    union {

        void        *generic_ip;

    } u;

#ifdef __NEED_I_SIZE_ORDERED

    seqcount_t        i_size_seqcount;

#endif

};

/include/linux/dcache.h

struct dentry {

    atomic_t d_count;

    unsigned int d_flags;        /* protected by d_lock */

    spinlock_t d_lock;        /* per dentry lock */

    struct inode *d_inode;        /* Where the name belongs to - NULL is

                     * negative */

    /*

     * The next three fields are touched by __d_lookup.  Place them here

     * so they all fit in a 16-byte range, with 16-byte alignment.

     */

    struct dentry *d_parent;    /* parent directory */

    struct qstr d_name;

    struct list_head d_lru;        /* LRU list */

    struct list_head d_child;    /* child of parent list */

    struct list_head d_subdirs;    /* our children */

    struct list_head d_alias;    /* inode alias list */

    unsigned long d_time;        /* used by d_revalidate */

    struct dentry_operations *d_op;

    struct super_block *d_sb;    /* The root of the dentry tree */

    void *d_fsdata;            /* fs-specific data */

     struct rcu_head d_rcu;

    struct dcookie_struct *d_cookie; /* cookie, if any */

    struct hlist_node d_hash;    /* lookup hash list */

    int d_mounted;

    unsigned char d_iname[DNAME_INLINE_LEN_MIN];    /* small names */

};