balloc.c

   1 #include <stdio.h>
   2 #include <malloc.h>
   3
   4 #include "tfs.h"
   5
   6 static void * tfs_read_block_bitmap(struct tfs_sb_info *sbi)
   7 {
   8         char *buf = malloc(sbi->s_block_size);
   9
  10         tfs_bread(sbi, sbi->s_block_bitmap, buf);
  11
  12         return buf;
  13 }
  14
  15 /*
  16  * Free a block, return -1 if failed, or return 0
  17  */
  18 int tfs_free_block(struct tfs_sb_info *sbi, uint32_t block)
  19 {
  20         char *bitmap = tfs_read_block_bitmap(sbi);
  21
  22         if (clear_bit(bitmap, block) == 0) {
  23                 printf("ERROR: trying to free an free block!\n");
  24                 free(bitmap);
  25                 return -1;
  26         }
  27
  28         tfs_bwrite(sbi, sbi->s_block_bitmap, bitmap);
  29         free(bitmap);
  30         return block;
  31 }
  32
  33 int tfs_alloc_block(struct tfs_sb_info *sbi, uint32_t block)
  34 {
  35         char *bitmap = tfs_read_block_bitmap(sbi);
  36
  37         /* try the target first */
  38         if (test_bit(bitmap, block) != 0)
  39                 block = find_first_zero(bitmap, bitmap + sbi->s_block_size);
  40         if (block != -1) {
  41                 set_bit(bitmap, block);
  42                 tfs_bwrite(sbi, sbi->s_block_bitmap, bitmap);
  43         }
  44
  45         free(bitmap);
  46         return block;
  47 }
  48
  49 #if 0  /* the deubg part */
  50 #include <stdlib.h>
  51 int main(int argc, char *argv[])
  52 {
  53         int i;
  54         int block;
  55         struct tfs_sb_info *sbi;
  56         char *fs = argv[1];
  57         char *command = argv[2];
  58         char **blocks = argv + 3;
  59         int count = argc - 3;
  60
  61         if (argc < 4) {
  62                 printf("Usage: balloc tfs.img command blocks...\n");
  63                 printf("       alloc, to alloc blocks\n");
  64                 printf("       feee,  to free blocks\n");
  65                 return 1;
  66         }
  67
  68         sbi = tfs_mount_by_fsname(fs);
  69         if (!sbi) {
  70                 printf("tfs mount failed!\n");
  71                 return 1;
  72         }
  73
  74         if (strcmp(command, "alloc") == 0) {
  75                 for (i = 0; i <  count; i++) {
  76                         block = atoi(blocks[i]);
  77                         printf("trying to alloc block %u\n", block);
  78                         block = tfs_alloc_block(sbi, block);
  79                         printf("block number: %u allocated\n", block);
  80                 }
  81         } else if (strcmp(command, "free") == 0) {
  82                 for (i = 0; i < count; i++) {
  83                         block = atoi(blocks[i]);
  84                         printf("trying to free block %u\n", block);
  85                         block = tfs_free_block(sbi, block);
  86                         printf("block number: %u freed\n", block);
  87                 }
  88         } else {
  89                 printf("Unknown command!\n");
  90         }
  91
  92         return 0;
  93 }
  94 #endif