hd_queue.h

/**
 * Hard disk buffers
 */
#ifndef _HD_QUEUE_H
#define _HD_QUEUE_H

#include "i386.h"

#define BLOCK_SIZE 512

// disk buffer //
typedef struct hd_buf {
    int block_no;         // disk block number it represents //
    bool is_dirty;        // was this buffer written into it? //
    int ref_count;        // how many pointers to this buf - if 0 - free //
    spin_lock_t lock;     // use it in locking the buffer
    char buf[BLOCK_SIZE]; // the data in this block
} hd_buf_t;

/**
 * Initialize hard disk queue
 */
int hd_queue_init();

/**
 * Get the buffer for block number block_no.
 */
hd_buf_t *get_hd_buf(int block_no);

/**
 * Release the buffer
 */
void put_hd_buf(hd_buf_t *hdb);

#endif