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302
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1 #include "types.h"
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2 #include "defs.h"
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3 #include "param.h"
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4 #include "stat.h"
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5 #include "mmu.h"
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6 #include "proc.h"
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7 #include "spinlock.h"
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8 #include "buf.h"
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9 #include "fs.h"
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10 #include "file.h"
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11 #interface "fs_impl.h"
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12
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13 /*
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14 fs_impl* createfs_impl2();
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15 */
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16
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304
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17 __code allocinode(struct fs_impl* fs_impl, uint dev, struct superblock* sb, __code next(int iget_val, ...)){ //:skip
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302
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18
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19 readsb(dev, sb);
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303
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20 Gearef(cbc_context, fs_impl)->inum = 1;
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304
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21 goto allocinode_loopcheck(fs_impl, inum, dev, sb, bp, dip, next(iget_val, ...));
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302
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22
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23 }
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24
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25 typedef struct buf buf;
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26 typedef struct dinode dinode;
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303
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27
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304
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28 __code allocinode_loopcheck(struct fs_impl* fs_impl, int inum, uint dev, struct superblock* sb, struct buf* bp, struct dinode* dip, __code next(int iget_val, ...)){ //:skip
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303
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29 if( inum < sb->ninodes){
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304
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30 goto allocinode_loop(fs_impl, inum, dev, type, sb, bp, dip, next(iget_val, ...));
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303
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31 }
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32 /*
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33 goto cbc_context->panic(...);
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34 */
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35 }
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302
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36
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304
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37 __code allocinode_loop(struct fs_impl* fs_impl, int inum, uint dev, short type, struct superblock* sb, struct buf* bp, struct dinode* dip, __code next(int iget_val, ...)){ //:skip
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303
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38 bp = bread(dev, IBLOCK(inum));
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39 dip = (struct dinode*) bp->data + inum % IPB;
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40 if(dip->type = 0){
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304
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41 goto allocinode_noloop(fs_impl, inum, dev, sb, bp, dip, next(iget_val, ...));
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303
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42 }
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43
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44 brelse(bp);
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45 inum++;
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304
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46 goto allocinode_loopcheck(fs_impl, inum, dev, type, sb, bp, dip, next(iget_val, ...));
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303
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47 }
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48
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304
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49 struct {
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50 struct spinlock lock;
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51 struct inode inode[NINODE];
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52 } icache;
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53
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54 static struct inode* iget (uint dev, uint inum)
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55 {
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56 struct inode *ip, *empty;
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57
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58 acquire(&icache.lock);
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59
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60 // Is the inode already cached?
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61 empty = 0;
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62
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63 for (ip = &icache.inode[0]; ip < &icache.inode[NINODE]; ip++) {
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64 if (ip->ref > 0 && ip->dev == dev && ip->inum == inum) {
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65 ip->ref++;
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66 release(&icache.lock);
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67 return ip;
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68 }
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69
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70 if (empty == 0 && ip->ref == 0) { // Remember empty slot.
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71 empty = ip;
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72 }
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73 }
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74
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75 // Recycle an inode cache entry.
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76 if (empty == 0) {
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77 panic("iget: no inodes");
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78 }
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79
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80 ip = empty;
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81 ip->dev = dev;
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82 ip->inum = inum;
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83 ip->ref = 1;
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84 ip->flags = 0;
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85 release(&icache.lock);
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86
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87 return ip;
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88 }
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89
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90 __code allocinode_noloop(struct fs_impl* fs_impl, int inum, uint dev, short type, struct superblock* sb, struct buf* bp, struct dinode* dip, __code next(int iget_val, ...)){ //:skip
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303
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91
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92 memset(dip, 0, sizeof(*dip));
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93 dip->type = type;
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94 log_write(bp);
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95 brelse(bp);
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96
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304
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97 iget_val = iget(dev, inum);
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303
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98 goto next(iget_val, ...);
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302
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99
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100 }
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303
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101
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306
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102 __code lockinode1(struct fs_impl* fs_impl, struct inode* ip, struct buf* bp, struct dinode* dip, __code next(...)){ //:skip
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103
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104 if (ip == 0 || ip->ref < 1) {
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105
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106 /*
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107 panic("ilock");
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108 goto panic();
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109 */
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110 }
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111 acquire(&icache.lock);
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112
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113 goto lockinode_sleepcheck(fs_impl, ip, next(...));
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114
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115 }
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116
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307
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117
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118 __code lockinode2(struct fs_impl* fs_impl, struct inode* ip, struct buf* bp, struct dinode* dip, __code next(...)){ //:skip
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119
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120 ip->flags |= I_BUSY;
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121 release(&icache.lock);
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122
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123 if (!(ip->flags & I_VALID)) {
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124 bp = bread(ip->dev, IBLOCK(ip->inum));
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125
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126 dip = (struct dinode*) bp->data + ip->inum % IPB;
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127 ip->type = dip->type;
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128 ip->major = dip->major;
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129 ip->minor = dip->minor;
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130 ip->nlink = dip->nlink;
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131 ip->size = dip->size;
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132
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133 memmove(ip->addrs, dip->addrs, sizeof(ip->addrs));
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134 brelse(bp);
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135 ip->flags |= I_VALID;
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136
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137 if (ip->type == 0) {
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138 /*
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139 panic("ilock: no type");
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140 goto panic();
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141 */
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142 }
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143 }
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144 goto next(...);
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145 }
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306
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146 __code lockinode_sleepcheck(struct fs_impl* fs_impl, struct inode* ip, __code next(...)){
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147 if(ip->flags & I_BUSY){
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148 sleep(ip, &icache.lock);
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149 goto lockinode_sleepcheck(fs_impl, ip, next(...));
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150 }
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307
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151 goto lockinode2(fs_impl, ip, bp, dip, next(...));
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152 }
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153
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154 __code iput_check(struct fs_impl* fs_impl, struct inode* ip, __code next(...)){
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155 acquire(&icache.lock);
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156 if (ip->ref == 1 && (ip->flags & I_VALID) && ip->nlink == 0) {
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157 goto iput_inode_nolink(fs_impl, ip, next(...));
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158 }
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159 ip->ref--;
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160 release(&icache.lock);
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161 goto next(...);
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162
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163 }
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164
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165 static void bfree (int dev, uint b)
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166 {
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167 struct buf *bp;
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168 struct superblock sb;
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169 int bi, m;
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170
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171 readsb(dev, &sb);
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172 bp = bread(dev, BBLOCK(b, sb.ninodes));
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173 bi = b % BPB;
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174 m = 1 << (bi % 8);
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175
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176 if ((bp->data[bi / 8] & m) == 0) {
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177 panic("freeing free block");
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178 }
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179
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180 bp->data[bi / 8] &= ~m;
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181 log_write(bp);
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182 brelse(bp);
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183 }
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184
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185
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186 static void itrunc (struct inode *ip)
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187 {
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188 int i, j;
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189 struct buf *bp;
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190 uint *a;
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191
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192 for (i = 0; i < NDIRECT; i++) {
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193 if (ip->addrs[i]) {
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194 bfree(ip->dev, ip->addrs[i]);
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195 ip->addrs[i] = 0;
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196 }
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197 }
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198
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199 if (ip->addrs[NDIRECT]) {
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200 bp = bread(ip->dev, ip->addrs[NDIRECT]);
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201 a = (uint*) bp->data;
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202
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203 for (j = 0; j < NINDIRECT; j++) {
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204 if (a[j]) {
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205 bfree(ip->dev, a[j]);
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206 }
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207 }
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208
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209 brelse(bp);
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210 bfree(ip->dev, ip->addrs[NDIRECT]);
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211 ip->addrs[NDIRECT] = 0;
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212 }
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213
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214 ip->size = 0;
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215 iupdate(ip);
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216 }
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217
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218 __code iput_inode_nolink(struct fs_impl* fs_impl, struct inode* ip, __code next(...)){
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219
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220 if (ip->flags & I_BUSY) {
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221 /*
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222 panic("iput busy");
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223 */
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224 }
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225
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226 ip->flags |= I_BUSY;
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227 release(&icache.lock);
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228 itrunc(ip);
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229 ip->type = 0;
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230 iupdate(ip);
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231
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232 acquire(&icache.lock);
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233 ip->flags = 0;
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234 wakeup(ip);
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305
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235 goto next(...);
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236 }
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306
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237
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307
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238
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