fs/tfs/balloc.c

   1 #include <stdio.h>
   2 #include <malloc.h>
   3 #include <bitopts.h>
   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                 printk("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 }