linux vfs 解析之 inode

最新推荐文章于 2025-05-31 03:41:52 发布

转载最新推荐文章于 2025-05-31 03:41:52 发布 · 744 阅读

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http://blog.sina.com.cn/s/blog_5219094a01009a4e.html

inode

相关的数据结构为:

struct inode {
struct hlist_node i_hash;
struct list_head i_list;
struct list_head i_sb_list;
struct list_head i_dentry;
unsigned long  i_ino;
atomic_t  i_count;
umode_t   i_mode;
unsigned int  i_nlink;
uid_t   i_uid;
gid_t   i_gid;
dev_t   i_rdev;
loff_t   i_size;
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;
spinlock_t  i_lock;
struct semaphore i_sem;
struct rw_semaphore i_alloc_sem;
struct inode_operations *i_op;
struct file_operations *i_fop;
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

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;
struct dnotify_struct *i_dnotify;
#endif

unsigned long i_state;
unsigned long dirtied_when;

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
};

inode存在于两个双向链表中:
一个是inode所在文件系统的super block的 s_inodes 链表中

一个是根据inode的使用状态存在于以下三个链表中的某个链表中:
1. 未用的: inode_unused 链表
2. 正在使用的: inode_in_use 链表
3. 脏的: super block中的s_dirty 链表

另外,还有一个重要的链表: inode_hashtable(这个暂不介绍).


            /------------\
/----------|super_blocks|----     ..........       ---------------------\
|          \------------/                                               |
|                                                                       |
|       super_block            super_block             super_block      |
|      +-----------+           +-----------+           +-----------+    |
\----->|  s_list   |<--------->|  s_list   |<--------->|  s_list   |<---/
        +-----------+           +-----------+           +-----------+
  ----->|  s_inodes |<---\      |  s_inodes |           |  s_inodes |
|      +-----------+    |      +-----------+           +-----------+
|      |  s_files  |    |      |  s_files  |           |  s_files  |
|      +-----------+    |      +-----------+           +-----------+
|      |           |    |      |           |      /--->|  s_dirty  |<-----\
|      +-----------+    |      +-----------+      |    +-----------+      |
|      |           |    |      |           |      |    |           |      |
|                       |                         |                       |
|                       |                         |                       |
|                       |                         |                       |
|                       |                         |                       |
|                       |                         |                       |
|                       |                         \-------------------\   |
|                       |                                             |   |
|                       \----- ...... ---------\                      |   |
|        inode                  inode          |        inode         |   |
|     +-----------+          +-----------+     |    +-----------+     |   |
|     |           |          |           |     |    |           |     |   |
|     +-----------+          +-----------+     |    +-----------+     |   |
\---->| i_sb_list |<-------->| i_sb_list |<----/    | i_sb_list |     |   |
       +-----------+          +-----------+          +-----------+     |   |
       |  i_hash   |          |  i_hash   |          |  i_hash   |     |   |
       +-----------+          +-----------+          +-----------+     |   |
/---->|  i_list   |<--\  /-->|  i_list   |<---\  /->|  i_list   |<----/   |
|     +-----------+   |  |   +-----------+    |  |  +-----------+         |
|     |           |   |  |   |           |    |  |  |           |         |
|                     |  |                    |  |                        |
|                     |  |                    |  |                        |
|                     |  |                    |  |                        |
|                     |  |                    |  |                        |
|                                             |  \------  ......  --------/
|                                             |
|                     .  .                    |
|                     .  .                    |
|  /------------\     .  .                    |
\->|inode_unused|-\   .  .                    |   /------------\
    \------------/ |   .  .                    \-->|inode_in_use|<---\
                   |   .  .                        \------------/    |
                   |                                                 |
  /------------- --/                                                 |
  |                    |  |                                          |
  |                    |  |                                          |
  |      inode         |  |               inode                      |
  |   +-----------+    |  |            +-----------+                 |
  |   | /         |    |  |            |           |                 |
  |   +-----------+    |  |            +-----------+                 |
  |   | i_sb_list |    |  |            | i_sb_list |                 |
  |   +-----------+    |  |            +-----------+                 |
  |   | |i_hash   |    |  |            |  i_hash   |                 |
  |   +-----------+    |  |            +-----------+                 |
  \-->|  i_list   |<---/  \----------->|  i_list   |<----------------/
      +-----------+                    +-----------+
      |           |                    |           |