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5f4c802880
* 对mkdir加锁 * 给mkdir和do_open的dentry加锁 * 对加锁进行了修改 * modified * bugfix: 修复一些死锁及空指针的错误 Co-authored-by: longjin <longjin@RinGoTek.cn>
128 lines
4.0 KiB
C
128 lines
4.0 KiB
C
#include "internal.h"
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#include <common/kfifo.h>
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#include <debug/bug.h>
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/**
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* @brief 释放dentry，并视情况自动释放inode. 在调用该函数前，需要将dentry加锁。
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*
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* @param dentry 目标dentry
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*
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* @return 错误码
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* 注意，当dentry指向文件时，如果返回值为正数，则表示在释放了该dentry后，该dentry指向的inode的引用计数。
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*/
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int vfs_dentry_put(struct vfs_dir_entry_t *dentry)
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{
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int retval = 0;
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uint64_t in_value = 0;
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struct kfifo_t fifo = {0};
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// 引用计数大于1时，尝试释放dentry的话，抛出错误信息
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if (unlikely(dentry->lockref.lock_count > 1))
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{
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BUG_ON(1);
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retval = -EBUSY;
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goto out;
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}
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if (D_ISDIR(dentry))
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{
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// 创建一个用来存放指向dentry的指针的fifo队列
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// 暂时假设队列大小为1024个元素
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// todo: 实现队列的自动扩容功能
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retval = kfifo_alloc(&fifo, 1024 * sizeof(uint64_t), 0);
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if (retval != 0)
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goto failed;
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// 将根dentry加入队列
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in_value = (uint64_t)dentry;
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kfifo_in(&fifo, &in_value, sizeof(uint64_t));
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list_del(&dentry->child_node_list); // 从父dentry中删除
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while (!kfifo_empty(&fifo))
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{
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// 取出队列中的下一个元素
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kfifo_out(&fifo, &dentry, sizeof(uint64_t));
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BUG_ON(dentry == NULL);
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struct List *list = &dentry->subdirs_list;
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if (!list_empty(list))
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{
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// 将当前dentry下的所有dentry加入队列
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do
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{
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list = list_next(list);
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in_value = (uint64_t)container_of(list, struct vfs_dir_entry_t, child_node_list);
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if (in_value != NULL)
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kfifo_in(&fifo, &in_value, sizeof(uint64_t));
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} while (list_next(list) != (&dentry->subdirs_list));
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}
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spin_lock(&dentry->lockref.lock);
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if(dentry->lockref.count>1)
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{
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spin_unlock(&dentry->lockref.lock);
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continue;
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}
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// 释放inode
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spin_lock(&dentry->dir_inode->lockref.lock);
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retval = vfs_free_inode(dentry->dir_inode);
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if (retval > 0) // 还有其他的dentry引用着这个inode
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{
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spin_unlock(&dentry->dir_inode->lockref.lock);
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retval = 0;
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}
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// 若当前dentry是否为挂载点，则umount
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if (is_local_mountpoint(dentry))
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do_umount(dentry);
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if (dentry->dir_ops->release != NULL)
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dentry->dir_ops->release(dentry);
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kfree(dentry);
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}
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kfifo_free_alloc(&fifo);
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retval = 0;
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goto out;
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}
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else // 是文件或设备
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{
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// 释放inode
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spin_lock(&dentry->dir_inode->lockref.lock);
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retval = vfs_free_inode(dentry->dir_inode);
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if (retval > 0) // 还有其他的dentry引用着这个inode
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spin_unlock(&dentry->dir_inode->lockref.lock);
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if (dentry->dir_ops->release != NULL)
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dentry->dir_ops->release(dentry);
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kfree(dentry);
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goto out;
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}
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failed:;
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if (fifo.buffer != NULL)
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kfifo_free_alloc(&fifo);
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kerror("dentry_put failed.");
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out:;
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// 在这里不用释放dentry的锁，因为dentry已经被释放掉了
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return retval;
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}
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/**
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* @brief 释放inode（要求已经对inode进行加锁后调用该函数）
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*
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* @param inode 待释放的inode
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* @return int 错误码
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* 当inode还有其他的使用者时，返回inode的使用者数量
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*/
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int vfs_free_inode(struct vfs_index_node_t *inode)
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{
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--inode->lockref.count;
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BUG_ON(inode->lockref.count < 0);
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if (inode->lockref.count == 0)
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{
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kfree(inode->private_inode_info);
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kfree(inode);
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return 0;
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}
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else // 如果inode没有被释放
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return inode->lockref.count;
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} |