forked from Mirrors/btrfs-progs
84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
#define _XOPEN_SOURCE 500
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "kerncompat.h"
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#include "radix-tree.h"
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#include "ctree.h"
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#include "disk-io.h"
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int mkfs(int fd)
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{
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struct btrfs_root_info info[2];
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struct btrfs_leaf empty_leaf;
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struct btrfs_item item;
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struct btrfs_extent_item extent_item;
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int ret;
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/* setup the super block area */
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memset(info, 0, sizeof(info));
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info[0].blocknr = 16;
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info[0].objectid = 1;
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info[0].tree_root = 17;
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info[1].blocknr = 16;
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info[1].objectid = 2;
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info[1].tree_root = 18;
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ret = pwrite(fd, info, sizeof(info),
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BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
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if (ret != sizeof(info))
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return -1;
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/* create leaves for the tree root and extent root */
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memset(&empty_leaf, 0, sizeof(empty_leaf));
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btrfs_set_header_parentid(&empty_leaf.header, 1);
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btrfs_set_header_blocknr(&empty_leaf.header, 17);
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ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 17 * BTRFS_BLOCKSIZE);
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if (ret != sizeof(empty_leaf))
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return -1;
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btrfs_set_header_parentid(&empty_leaf.header, 2);
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btrfs_set_header_blocknr(&empty_leaf.header, 18);
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btrfs_set_header_nritems(&empty_leaf.header, 3);
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/* item1, reserve blocks 0-16 */
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btrfs_set_key_objectid(&item.key, 0);
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btrfs_set_key_offset(&item.key, 17);
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btrfs_set_key_flags(&item.key, 0);
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btrfs_set_item_offset(&item, LEAF_DATA_SIZE -
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sizeof(struct btrfs_extent_item));
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btrfs_set_item_size(&item, sizeof(struct btrfs_extent_item));
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btrfs_set_extent_refs(&extent_item, 1);
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btrfs_set_extent_owner(&extent_item, 0);
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memcpy(empty_leaf.items, &item, sizeof(item));
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memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
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btrfs_item_size(&item));
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/* item2, give block 17 to the root */
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btrfs_set_key_objectid(&item.key, 17);
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btrfs_set_key_offset(&item.key, 1);
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btrfs_set_item_offset(&item, LEAF_DATA_SIZE -
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sizeof(struct btrfs_extent_item) * 2);
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btrfs_set_extent_owner(&extent_item, 1);
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memcpy(empty_leaf.items + 1, &item, sizeof(item));
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memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
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btrfs_item_size(&item));
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/* item3, give block 18 for the extent root */
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btrfs_set_key_objectid(&item.key, 18);
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btrfs_set_key_offset(&item.key, 1);
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btrfs_set_item_offset(&item, LEAF_DATA_SIZE -
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sizeof(struct btrfs_extent_item) * 3);
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btrfs_set_extent_owner(&extent_item, 2);
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memcpy(empty_leaf.items + 2, &item, sizeof(item));
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memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
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btrfs_item_size(&item));
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ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 18 * BTRFS_BLOCKSIZE);
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if (ret != sizeof(empty_leaf))
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return -1;
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return 0;
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}
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