Table of Contents Source Extend 附图 Ref Caller

7336

7337 /*

7338  * Decrement reference count of

7339  * an inode structure.

7340  * On the last reference,

7341  * write the inode out and if necessary,

7342  * truncate and deallocate the file.

7343  */

7344 iput(p)

7345 struct inode *p;

7346 {

7347     register *rp;

7348

7349     rp = p;

7350     if(rp->i_count == 1) {

7351          rp->i_flag =| ILOCK;

7352          if(rp->i_nlink <= 0) {

7353           itrunc(rp);

7354           rp->i_mode = 0;

7355           ifree(rp->i_dev, rp->i_number);

7356          }

• 若勾连数<=0，则inode代表的文件已从文件系统中被删除(不可通过查找找到其存在)，则
  • itrunc释放inode对应的文件块
  • 清零 i_mode
  • ifree释放磁盘上的inode块(但未写回磁盘，写回操作在7357)

7357          iupdat(rp, time);

7358          prele(rp);

• 7358 与 7363 在此分支执行时重复
• 7358 是为了在释放内存inode块之前 解锁并唤醒等待进程
• 7363在此分支执行时 多余

7359          rp->i_flag = 0;

7360          rp->i_number = 0;

• 相当于释放内存inode块

7361     }

7362     rp->i_count--;

7363     prele(rp);

7364 }

7365 /* ------------------------- */

• 文件系统
• 设备缓存管理

• code:exec
• code:exit
• code:unlink
• code:chdir
• code:chmod
• code:chown
• code:smdate
• code:core
• code:xfree
• code:open1
• code:link
• code:mknod
• code:stat
• code:smount
• code:sumount
• code:getmdev
• code:closei
• code:owner
• code:ialloc
• code:iget
• code:wdir
• code:namei
• code:pipe