mkfs.c

   1 #define _XOPEN_SOURCE 500
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <fcntl.h>
   7 #include <unistd.h>
   8 #include "kerncompat.h"
   9 #include "radix-tree.h"
  10 #include "ctree.h"
  11 #include "disk-io.h"
  12
  13 int mkfs(int fd)
  14 {
  15         struct ctree_root_info info[2];
  16         struct leaf empty_leaf;
  17         struct item item;
  18         struct extent_item extent_item;
  19         int ret;
  20
  21         /* setup the super block area */
  22         memset(info, 0, sizeof(info));
  23         info[0].blocknr = 16;
  24         info[0].objectid = 1;
  25         info[0].tree_root = 17;
  26
  27         info[1].blocknr = 16;
  28         info[1].objectid = 2;
  29         info[1].tree_root = 18;
  30         ret = pwrite(fd, info, sizeof(info),
  31                      CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
  32         if (ret != sizeof(info))
  33                 return -1;
  34
  35         /* create leaves for the tree root and extent root */
  36         memset(&empty_leaf, 0, sizeof(empty_leaf));
  37         empty_leaf.header.parentid = 1;
  38         empty_leaf.header.blocknr = 17;
  39         ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 17 * CTREE_BLOCKSIZE);
  40         if (ret != sizeof(empty_leaf))
  41                 return -1;
  42
  43         empty_leaf.header.parentid = 2;
  44         empty_leaf.header.blocknr = 18;
  45         empty_leaf.header.nritems = 3;
  46
  47         /* item1, reserve blocks 0-16 */
  48         item.key.objectid = 0;
  49         item.key.offset = 17;
  50         item.key.flags = 0;
  51         item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item);
  52         item.size = sizeof(struct extent_item);
  53         extent_item.refs = 1;
  54         extent_item.owner = 0;
  55         memcpy(empty_leaf.items, &item, sizeof(item));
  56         memcpy(empty_leaf.data + item.offset, &extent_item, item.size);
  57
  58         /* item2, give block 17 to the root */
  59         item.key.objectid = 17;
  60         item.key.offset = 1;
  61         item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item) * 2;
  62         extent_item.owner = 1;
  63         memcpy(empty_leaf.items + 1, &item, sizeof(item));
  64         memcpy(empty_leaf.data + item.offset, &extent_item, item.size);
  65
  66         /* item3, give block 18 for the extent root */
  67         item.key.objectid = 18;
  68         item.key.offset = 1;
  69         item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item) * 3;
  70         extent_item.owner = 2;
  71         memcpy(empty_leaf.items + 2, &item, sizeof(item));
  72         memcpy(empty_leaf.data + item.offset, &extent_item, item.size);
  73         ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 18 * CTREE_BLOCKSIZE);
  74         if (ret != sizeof(empty_leaf))
  75                 return -1;
  76         return 0;
  77 }