470 lines
16 KiB
C++
470 lines
16 KiB
C++
#include "rawdisk.h"
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/*****************************************************
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30GB Disk low-level operation and data structure: spuerblock, inode, and buffer cache
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512 bytes sector for 1 block, 62914560 block(sector)
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4K bytes sector for 1 block, 7864320 block(sector)
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one inode equipped with one 512 bytes block
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*****************************************************/
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#define SECTOR_SIZE 512
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#define IO_BLOCK_SIZE 4096
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#define MAX_INODE 524288
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#define MAX_BLOCKNUM MAX_INODE*2 //62914560
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class SuperBlock{
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public:
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SuperBlock(){
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}
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~SuperBlock(){
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}
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static u_int64_t getFreeListHead(RawDisk &disk){
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char buffer[8] = {0};
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disk.rawdisk_read(0, buffer, sizeof(buffer));
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u_int64_t t = 0;
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for (int j = 0; j < 8; j++)
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t = t | (((u_int64_t)(unsigned char)buffer[j])<<(8*j));
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return t;
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}
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static void writeFreeListHead(RawDisk &disk, u_int64_t t){
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char buffer[8] = {0};
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for (int j = 0; j < 8; j++){
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buffer[j] = (t >> (8 * j)) & 0xFF;
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}
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disk.rawdisk_write(0, buffer, sizeof(buffer));
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}
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static u_int64_t getFreeINodeHead(RawDisk &disk){
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char buffer[8] = {0};
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disk.rawdisk_read(8, buffer, sizeof(buffer));
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u_int64_t t = 0;
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for (int j = 0; j < 8; j++)
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t = t | (((u_int64_t)(unsigned char)buffer[j])<<(8*j));
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return t;
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}
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static void writeFreeINodeHead(RawDisk &disk, u_int64_t t){
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char buffer[8] = {0};
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for (int j = 0; j < 8; j++){
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buffer[j] = (t >> (8 * j)) & 0xFF;
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}
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disk.rawdisk_write(8, buffer, sizeof(buffer));
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}
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};
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class INode{
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public:
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// direct datablocks
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u_int64_t blocks[48];
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// indirect address
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u_int64_t single_indirect, double_indirect, triple_indirect;
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// other
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u_int64_t uid;
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u_int64_t gid;
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u_int64_t permissions;
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u_int64_t size; // Number of datablocks
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u_int64_t block_number;
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public:
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void read_get_byte(u_int64_t &t, int ¤t_pos, char *buffer){
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t = 0;
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for (int j = 0; j < 8; j++)
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t = t | (((u_int64_t)(unsigned char)buffer[j+current_pos])<<(8*j));
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current_pos += 8;
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}
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static u_int64_t read_byte_at(int current_pos, char *buffer){
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u_int64_t t = 0;
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for (int j = 0; j < 8; j++)
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t = t | (((u_int64_t)(unsigned char)buffer[j+current_pos])<<(8*j));
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return t;
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}
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void inode_construct(u_int64_t blockNumber, RawDisk &disk){
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char buffer[SECTOR_SIZE] = {0};
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disk.rawdisk_read(blockNumber*SECTOR_SIZE, buffer, sizeof(buffer));
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block_number = blockNumber;
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int current_pos = 0;
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// initialize blocks
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for (int i = 0; i < 48; i++){
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read_get_byte(blocks[i], current_pos, buffer);
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}
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read_get_byte(single_indirect, current_pos, buffer);
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read_get_byte(double_indirect, current_pos, buffer);
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read_get_byte(triple_indirect, current_pos, buffer);
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read_get_byte(uid, current_pos, buffer);
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read_get_byte(gid, current_pos, buffer);
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read_get_byte(permissions, current_pos, buffer);
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read_get_byte(size, current_pos, buffer);
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}
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void write_get_byte(u_int64_t t, int ¤t_pos, char *buffer){
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for (int j = 0; j < 8; j++){
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buffer[j+current_pos] = t & (((u_int64_t)1<<(8))-1);
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t >>= 8;
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}
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current_pos += 8;
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}
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static void write_byte_at(u_int64_t t, int current_pos, char *buffer){
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for (int j = 0; j < 8; j++){
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buffer[j+current_pos] = t & (((u_int64_t)1<<(8))-1);
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t >>= 8;
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}
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}
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void inode_save(RawDisk &disk){
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char buffer[SECTOR_SIZE] = {0};
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int current_pos = 0;
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for (int i = 0; i < 48; i++){
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write_get_byte(blocks[i], current_pos, buffer);
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}
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write_get_byte(single_indirect, current_pos, buffer);
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write_get_byte(double_indirect, current_pos, buffer);
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write_get_byte(triple_indirect, current_pos, buffer);
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write_get_byte(uid, current_pos, buffer);
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write_get_byte(gid, current_pos, buffer);
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write_get_byte(permissions, current_pos, buffer);
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write_get_byte(size, current_pos, buffer);
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disk.rawdisk_write(block_number*SECTOR_SIZE, buffer, sizeof(buffer));
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}
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u_int64_t datablock_allocate_in_list(RawDisk &disk){
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//find a free data block
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u_int64_t freeListHead = SuperBlock::getFreeListHead(disk);
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/*
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1. initialization
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2. data block starting position
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3. r/w between storage and rawdisk to maintain
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*/
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char buffer[IO_BLOCK_SIZE] = {0};
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u_int64_t freeBlockNum = 0;
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disk.rawdisk_read(freeListHead, buffer, sizeof(buffer));
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for (int i = 8; i < 264; i++){
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if((i < 263 && buffer[i] != -1) || (i == 263 && buffer[i] != 127)){
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int j = 0;
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for (j = 0; j < 8; j++){
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if ((buffer[i]&(1<<j)) == 0){
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buffer[i] |= (1<<j);
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break;
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}
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}
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if (j < 8){
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freeBlockNum = freeListHead + ((i-8)*8 + j + 1)*IO_BLOCK_SIZE;
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break;
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}
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}
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}
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disk.rawdisk_write(freeListHead, buffer, sizeof(buffer));
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bool notFull = false;
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for (int i = 8; i < 264; i++){
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if((i < 263 && buffer[i] != -1) || (i == 263 && buffer[i] != 127)){
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notFull = true;
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break;
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}
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}
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if (!notFull){
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printf("HEADER REMOVAL DETECTED %llu %llu\n", freeListHead, freeBlockNum);
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u_int64_t next_header = read_byte_at(0, buffer);
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SuperBlock::writeFreeListHead(disk, next_header);
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}
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return freeBlockNum;
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}
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bool allo_single_indirect(RawDisk &disk, u_int64_t &single_i, u_int64_t freeBlockNum) {
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if (single_i == 0){
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single_i = datablock_allocate_in_list(disk);
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char new_buffer[IO_BLOCK_SIZE] = {0};
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disk.rawdisk_write(single_i, new_buffer, sizeof(new_buffer));
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}
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bool inSingle = false;
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char buffer[IO_BLOCK_SIZE] = {0};
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disk.rawdisk_read(single_i, buffer, sizeof(buffer));
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for (int i = 0; i < IO_BLOCK_SIZE; i+=8){
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u_int64_t addr = read_byte_at(i, buffer);
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if(addr == 0){
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inSingle = true;
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write_byte_at(freeBlockNum, i, buffer);
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disk.rawdisk_write(single_i, buffer, sizeof(buffer));
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break;
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}
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}
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return inSingle;
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}
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bool allo_double_indirect(RawDisk &disk, u_int64_t &double_i, u_int64_t freeBlockNum) {
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if (double_i == 0){
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double_i = datablock_allocate_in_list(disk);
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char new_buffer[IO_BLOCK_SIZE] = {0};
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disk.rawdisk_write(double_i, new_buffer, sizeof(new_buffer));
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}
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bool inDouble = false;
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char buffer[IO_BLOCK_SIZE] = {0};
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disk.rawdisk_read(double_i, buffer, sizeof(buffer));
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for (int i = 0; i < IO_BLOCK_SIZE; i+=8){
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u_int64_t addr = read_byte_at(i, buffer);
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bool flag = allo_single_indirect(disk, addr, freeBlockNum);
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if (flag){
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write_byte_at(addr, i, buffer);
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disk.rawdisk_write(double_i, buffer, sizeof(buffer));
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inDouble = true;
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break;
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}
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}
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return inDouble;
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}
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bool allo_triple_indirect(RawDisk &disk, u_int64_t &triple_i, u_int64_t freeBlockNum) {
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if (triple_i == 0){
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triple_i = datablock_allocate_in_list(disk);
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char new_buffer[IO_BLOCK_SIZE] = {0};
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disk.rawdisk_write(triple_i, new_buffer, sizeof(new_buffer));
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}
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bool inTriple = false;
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char buffer[IO_BLOCK_SIZE] = {0};
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disk.rawdisk_read(triple_i, buffer, sizeof(buffer));
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for (int i = 0; i < IO_BLOCK_SIZE; i+=8){
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u_int64_t addr = read_byte_at(i, buffer);
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bool flag = allo_double_indirect(disk, addr, freeBlockNum);
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if (flag){
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write_byte_at(addr, i, buffer);
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disk.rawdisk_write(triple_i, buffer, sizeof(buffer));
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inTriple = true;
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break;
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}
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}
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return inTriple;
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}
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// allowcate 1 datablock and add to the end of the file
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u_int64_t datablock_allocate(RawDisk &disk){
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//do we need to check dynamic?
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//add the data block to blocks, single, double, triple
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u_int64_t freeBlockNum = datablock_allocate_in_list(disk);
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bool inBlocks = false;
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for (int i = 0; i < 48; i++)
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if(blocks[i] == 0){
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inBlocks = true;
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blocks[i] = freeBlockNum;
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break;
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}
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if(!inBlocks){
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bool inSingle = allo_single_indirect(disk, single_indirect, freeBlockNum);
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if (!inSingle){
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bool inDouble = allo_double_indirect(disk, double_indirect, freeBlockNum);
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if (!inDouble){
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bool inTriple = allo_triple_indirect(disk, triple_indirect, freeBlockNum);
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// wait to deal with too big files
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}
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}
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}
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//return the block number
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inode_save(disk);
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return freeBlockNum;
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}
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void datablock_deallocate_in_list(u_int64_t freeBlockNum, RawDisk &disk) {
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// find the related 2048block head
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u_int64_t freeBlockHead = ((freeBlockNum/SECTOR_SIZE-MAX_INODE)/(8*2048)*(8*2048)+MAX_INODE)*SECTOR_SIZE;
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// mark it alive in its bitmap
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char buffer[IO_BLOCK_SIZE] = {0};
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bool nowInList = false;
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disk.rawdisk_read(freeBlockHead, buffer, sizeof(buffer));
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for (int i = 8; i < 264; i++){
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if((i < 263 && buffer[i] != -1) || (i == 263 && buffer[i] != 127)){
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nowInList = true;
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}
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}
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u_int64_t inBlockPos = (freeBlockNum-freeBlockHead)/IO_BLOCK_SIZE-1;
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buffer[8+inBlockPos/8] &= (-1)^(1<<(inBlockPos%8));
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// if its bitmap was 0, add it back to the list head
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if(!nowInList){
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u_int64_t freeListHead = SuperBlock::getFreeListHead(disk);
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write_byte_at(freeListHead, 0, buffer);
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SuperBlock::writeFreeListHead(disk, freeBlockHead);
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}
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disk.rawdisk_write(freeBlockHead, buffer, sizeof(buffer));
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}
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u_int64_t deallo_single_indirect(RawDisk &disk, u_int64_t &single_i){
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if (single_i == 0){
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return 0;
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}
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u_int64_t freeBlockNum = 0;
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char buffer[IO_BLOCK_SIZE] = {0};
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int delpoint = -1;
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disk.rawdisk_read(single_i, buffer, sizeof(buffer));
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for (int i=4088; i >= 0; i-=8){
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u_int64_t addr = read_byte_at(i, buffer);
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if(addr != 0){
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freeBlockNum = addr;
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addr = 0;
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write_byte_at(addr, i, buffer);
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delpoint = i;
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break;
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}
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}
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disk.rawdisk_write(single_i, buffer, sizeof(buffer));
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u_int64_t addr = read_byte_at(0, buffer);
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if (delpoint == 0 && addr == 0){
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datablock_deallocate_in_list(single_i, disk);
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single_i = 0;
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}
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return freeBlockNum;
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}
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u_int64_t deallo_double_indirect(RawDisk &disk, u_int64_t &double_i){
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if (double_i == 0){
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return false;
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}
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u_int64_t freeBlockNum = 0;
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char buffer[IO_BLOCK_SIZE] = {0};
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int delpoint = -1;
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disk.rawdisk_read(double_i, buffer, sizeof(buffer));
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for (int i=4088; i >= 0; i-=8){
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u_int64_t addr = read_byte_at(i, buffer);
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u_int64_t inSingle = deallo_single_indirect(disk, addr);
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if (inSingle){
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freeBlockNum = inSingle;
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write_byte_at(addr, i, buffer);
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delpoint = i;
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break;
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}
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}
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disk.rawdisk_write(double_i, buffer, sizeof(buffer));
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u_int64_t addr = read_byte_at(0, buffer);
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if (delpoint == 0 && addr == 0){
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datablock_deallocate_in_list(double_i, disk);
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double_i = 0;
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}
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return freeBlockNum;
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}
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u_int64_t deallo_triple_indirect(RawDisk &disk, u_int64_t &triple_i){
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if (triple_i == 0){
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return false;
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}
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u_int64_t freeBlockNum = 0;
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char buffer[IO_BLOCK_SIZE] = {0};
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int delpoint = -1;
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disk.rawdisk_read(triple_i, buffer, sizeof(buffer));
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for (int i=4088; i >= 0; i-=8){
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u_int64_t addr = read_byte_at(i, buffer);
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u_int64_t inDouble = deallo_double_indirect(disk, addr);
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if (inDouble){
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freeBlockNum = inDouble;
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write_byte_at(addr, i, buffer);
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delpoint = i;
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break;
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}
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}
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disk.rawdisk_write(triple_i, buffer, sizeof(buffer));
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u_int64_t addr = read_byte_at(0, buffer);
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if (delpoint == 0 && addr == 0){
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datablock_deallocate_in_list(triple_i, disk);
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triple_i = 0;
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}
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return freeBlockNum;
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}
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// deallocate 1 datablock from the end of the file
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u_int64_t datablock_deallocate(RawDisk &disk){
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// find the last datablock and remove it from inode (triple->direct)
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u_int64_t freeBlockNum = 0;
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freeBlockNum = deallo_triple_indirect(disk, triple_indirect);
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if(!freeBlockNum){
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freeBlockNum = deallo_double_indirect(disk, double_indirect);
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if(!freeBlockNum){
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freeBlockNum = deallo_single_indirect(disk, single_indirect);
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if(!freeBlockNum){
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for(int i = 47; i>=0; i--)
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if(blocks[i] != 0){
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freeBlockNum = blocks[i];
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blocks[i] = 0;
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break;
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}
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// deal with empty
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}
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}
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}
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// add it back to freeBlocklist
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datablock_deallocate_in_list(freeBlockNum, disk);
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inode_save(disk);
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return freeBlockNum;
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}
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};
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class INodeOperation{
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// free list head is at super block (0): first 8 bytes
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public:
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//initialization of the rawdisk
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void initialize(RawDisk &disk){
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// initialize Inode list head
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SuperBlock::writeFreeINodeHead(disk, 1);
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for (u_int64_t i = 1; i < MAX_INODE; i++){
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char buffer[SECTOR_SIZE] = {0};
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u_int64_t t = i + 1;
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if (t < MAX_INODE){
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for (int j = 0; j < 8; j++){
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buffer[j] = (t >> (8 * j)) & 0xFF;
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}
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}
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disk.rawdisk_write(i*SECTOR_SIZE, buffer, sizeof(buffer));
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}
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SuperBlock::writeFreeListHead(disk, MAX_INODE*SECTOR_SIZE); // maximum inode number 2^19 0x80000
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//Have tested this initialize function but MAX_BLOCK too much, MAX_INODE*2 works
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for (u_int64_t i = MAX_INODE; i < MAX_BLOCKNUM-4096; i += 2048*8){
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char buffer[IO_BLOCK_SIZE] = {0};
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u_int64_t t = (i + 2048*8)*SECTOR_SIZE;
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//t is address, storing in to buffer
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for (int j = 0; j < 8; j++){
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buffer[j] = (t >> (8 * j)) & 0xFF;
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}
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disk.rawdisk_write(i*SECTOR_SIZE, buffer, sizeof(buffer));
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}
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}
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// allocate an inode from free inode list head and return the number of the inode
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// the i-th inode is in the i-th block
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u_int64_t inode_allocate(RawDisk &disk){
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u_int64_t freeINodeHead = SuperBlock::getFreeINodeHead(disk);
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char buffer[SECTOR_SIZE] = {0};
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disk.rawdisk_read(freeINodeHead*SECTOR_SIZE, buffer, sizeof(buffer));
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u_int64_t newINodeHead = INode::read_byte_at(0, buffer);
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// deal with no more INode
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SuperBlock::writeFreeINodeHead(disk, newINodeHead);
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//to do: initialize the INode on disk at freeINodeHead
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//return inode number
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return freeINodeHead;
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}
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// free the inode and add it to the free inode list head
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void inode_free(RawDisk &disk, u_int64_t INodeNumber){
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u_int64_t freeINodeHead = SuperBlock::getFreeINodeHead(disk);
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char buffer[SECTOR_SIZE] = {0};
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INode::write_byte_at(freeINodeHead, 0, buffer);
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disk.rawdisk_write(INodeNumber*SECTOR_SIZE, buffer, sizeof(buffer));
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SuperBlock::writeFreeINodeHead(disk, INodeNumber);
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}
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//ignore for now
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void inode_read(){
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|
}
|
|
|
|
void inode_write(){
|
|
|
|
}
|
|
}; |