1 #define _XOPEN_SOURCE 500
8 #include "kerncompat.h"
9 #include "radix-tree.h"
13 int mkfs(int fd
, u64 num_blocks
, u32 blocksize
)
15 struct btrfs_super_block super
;
16 struct btrfs_leaf
*empty_leaf
;
17 struct btrfs_root_item root_item
;
18 struct btrfs_item item
;
19 struct btrfs_extent_item extent_item
;
23 u32 start_block
= BTRFS_SUPER_INFO_OFFSET
/ blocksize
;
25 btrfs_set_super_blocknr(&super
, start_block
);
26 btrfs_set_super_root(&super
, start_block
+ 1);
27 strcpy((char *)(&super
.magic
), BTRFS_MAGIC
);
28 btrfs_set_super_blocksize(&super
, blocksize
);
29 btrfs_set_super_total_blocks(&super
, num_blocks
);
30 btrfs_set_super_blocks_used(&super
, 0);
32 block
= malloc(blocksize
);
33 memset(block
, 0, blocksize
);
34 BUG_ON(sizeof(super
) > blocksize
);
35 memcpy(block
, &super
, sizeof(super
));
36 ret
= pwrite(fd
, block
, blocksize
, BTRFS_SUPER_INFO_OFFSET
);
37 BUG_ON(ret
!= blocksize
);
39 /* create the tree of root objects */
40 empty_leaf
= malloc(blocksize
);
41 memset(empty_leaf
, 0, blocksize
);
42 btrfs_set_header_parentid(&empty_leaf
->header
,
43 BTRFS_ROOT_TREE_OBJECTID
);
44 btrfs_set_header_blocknr(&empty_leaf
->header
, start_block
+ 1);
45 btrfs_set_header_nritems(&empty_leaf
->header
, 2);
47 /* create the items for the root tree */
48 btrfs_set_root_blocknr(&root_item
, start_block
+ 2);
49 btrfs_set_root_refs(&root_item
, 1);
50 itemoff
= __BTRFS_LEAF_DATA_SIZE(blocksize
) - sizeof(root_item
);
51 btrfs_set_item_offset(&item
, itemoff
);
52 btrfs_set_item_size(&item
, sizeof(root_item
));
53 btrfs_set_key_objectid(&item
.key
, BTRFS_EXTENT_TREE_OBJECTID
);
54 btrfs_set_key_offset(&item
.key
, 0);
55 btrfs_set_key_flags(&item
.key
, 0);
56 memcpy(empty_leaf
->items
, &item
, sizeof(item
));
57 memcpy(btrfs_leaf_data(empty_leaf
) + itemoff
,
58 &root_item
, sizeof(root_item
));
60 btrfs_set_root_blocknr(&root_item
, start_block
+ 3);
61 itemoff
= itemoff
- sizeof(root_item
);
62 btrfs_set_item_offset(&item
, itemoff
);
63 btrfs_set_key_objectid(&item
.key
, BTRFS_FS_TREE_OBJECTID
);
64 memcpy(empty_leaf
->items
+ 1, &item
, sizeof(item
));
65 memcpy(btrfs_leaf_data(empty_leaf
) + itemoff
,
66 &root_item
, sizeof(root_item
));
67 ret
= pwrite(fd
, empty_leaf
, blocksize
, (start_block
+ 1) * blocksize
);
69 /* create the items for the extent tree */
70 btrfs_set_header_parentid(&empty_leaf
->header
,
71 BTRFS_EXTENT_TREE_OBJECTID
);
72 btrfs_set_header_blocknr(&empty_leaf
->header
, start_block
+ 2);
73 btrfs_set_header_nritems(&empty_leaf
->header
, 4);
75 /* item1, reserve blocks 0-16 */
76 btrfs_set_key_objectid(&item
.key
, 0);
77 btrfs_set_key_offset(&item
.key
, start_block
+ 1);
78 btrfs_set_key_flags(&item
.key
, 0);
79 itemoff
= __BTRFS_LEAF_DATA_SIZE(blocksize
) -
80 sizeof(struct btrfs_extent_item
);
81 btrfs_set_item_offset(&item
, itemoff
);
82 btrfs_set_item_size(&item
, sizeof(struct btrfs_extent_item
));
83 btrfs_set_extent_refs(&extent_item
, 1);
84 btrfs_set_extent_owner(&extent_item
, 0);
85 memcpy(empty_leaf
->items
, &item
, sizeof(item
));
86 memcpy(btrfs_leaf_data(empty_leaf
) + btrfs_item_offset(&item
),
87 &extent_item
, btrfs_item_size(&item
));
89 /* item2, give block 17 to the root */
90 btrfs_set_key_objectid(&item
.key
, start_block
+ 1);
91 btrfs_set_key_offset(&item
.key
, 1);
92 itemoff
= itemoff
- sizeof(struct btrfs_extent_item
);
93 btrfs_set_item_offset(&item
, itemoff
);
94 btrfs_set_extent_owner(&extent_item
, BTRFS_ROOT_TREE_OBJECTID
);
95 memcpy(empty_leaf
->items
+ 1, &item
, sizeof(item
));
96 memcpy(btrfs_leaf_data(empty_leaf
) + btrfs_item_offset(&item
),
97 &extent_item
, btrfs_item_size(&item
));
99 /* item3, give block 18 to the extent root */
100 btrfs_set_key_objectid(&item
.key
, start_block
+ 2);
101 btrfs_set_key_offset(&item
.key
, 1);
102 itemoff
= itemoff
- sizeof(struct btrfs_extent_item
);
103 btrfs_set_item_offset(&item
, itemoff
);
104 btrfs_set_extent_owner(&extent_item
, BTRFS_EXTENT_TREE_OBJECTID
);
105 memcpy(empty_leaf
->items
+ 2, &item
, sizeof(item
));
106 memcpy(btrfs_leaf_data(empty_leaf
) + btrfs_item_offset(&item
),
107 &extent_item
, btrfs_item_size(&item
));
109 /* item4, give block 19 to the FS root */
110 btrfs_set_key_objectid(&item
.key
, start_block
+ 3);
111 btrfs_set_key_offset(&item
.key
, 1);
112 itemoff
= itemoff
- sizeof(struct btrfs_extent_item
);
113 btrfs_set_item_offset(&item
, itemoff
);
114 btrfs_set_extent_owner(&extent_item
, BTRFS_FS_TREE_OBJECTID
);
115 memcpy(empty_leaf
->items
+ 3, &item
, sizeof(item
));
116 memcpy(btrfs_leaf_data(empty_leaf
) + btrfs_item_offset(&item
),
117 &extent_item
, btrfs_item_size(&item
));
118 ret
= pwrite(fd
, empty_leaf
, blocksize
, (start_block
+ 2) * blocksize
);
119 if (ret
!= blocksize
)
122 /* finally create the FS root */
123 btrfs_set_header_parentid(&empty_leaf
->header
, BTRFS_FS_TREE_OBJECTID
);
124 btrfs_set_header_blocknr(&empty_leaf
->header
, start_block
+ 3);
125 btrfs_set_header_nritems(&empty_leaf
->header
, 0);
126 ret
= pwrite(fd
, empty_leaf
, blocksize
, (start_block
+ 3) * blocksize
);
127 if (ret
!= blocksize
)