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eb60ceac CM |
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 | static int allocated_blocks = 0; | |
14 | ||
15 | struct ctree_header { | |
16 | u64 root_block; | |
17 | } __attribute__ ((__packed__)); | |
18 | ||
19 | static int get_free_block(struct ctree_root *root, u64 *block) | |
20 | { | |
21 | struct stat st; | |
22 | int ret; | |
23 | ||
24 | st.st_size = 0; | |
25 | ret = fstat(root->fp, &st); | |
26 | if (st.st_size > sizeof(struct ctree_header)) { | |
27 | *block = (st.st_size - | |
28 | sizeof(struct ctree_header)) / CTREE_BLOCKSIZE; | |
29 | } else { | |
30 | *block = 0; | |
31 | } | |
32 | ret = ftruncate(root->fp, sizeof(struct ctree_header) + (*block + 1) * | |
33 | CTREE_BLOCKSIZE); | |
34 | return ret; | |
35 | } | |
36 | ||
37 | struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr) | |
38 | { | |
39 | struct tree_buffer *buf; | |
40 | int ret; | |
41 | buf = malloc(sizeof(struct tree_buffer)); | |
42 | if (!buf) | |
43 | return buf; | |
44 | allocated_blocks++; | |
45 | buf->blocknr = blocknr; | |
46 | buf->count = 1; | |
47 | radix_tree_preload(GFP_KERNEL); | |
48 | ret = radix_tree_insert(&root->cache_radix, blocknr, buf); | |
49 | radix_tree_preload_end(); | |
50 | if (ret) { | |
51 | free(buf); | |
52 | return NULL; | |
53 | } | |
54 | return buf; | |
55 | } | |
56 | ||
57 | struct tree_buffer *alloc_free_block(struct ctree_root *root) | |
58 | { | |
59 | u64 free_block; | |
60 | int ret; | |
61 | struct tree_buffer * buf; | |
62 | ret = get_free_block(root, &free_block); | |
63 | if (ret) { | |
64 | BUG(); | |
65 | return NULL; | |
66 | } | |
67 | buf = alloc_tree_block(root, free_block); | |
68 | if (!buf) | |
69 | BUG(); | |
70 | return buf; | |
71 | } | |
72 | ||
73 | struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr) | |
74 | { | |
75 | loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header); | |
76 | struct tree_buffer *buf; | |
77 | int ret; | |
78 | ||
79 | buf = radix_tree_lookup(&root->cache_radix, blocknr); | |
80 | if (buf) { | |
81 | buf->count++; | |
82 | if (buf->blocknr != blocknr) | |
83 | BUG(); | |
84 | if (buf->blocknr != buf->node.header.blocknr) | |
85 | BUG(); | |
86 | return buf; | |
87 | } | |
88 | buf = alloc_tree_block(root, blocknr); | |
89 | if (!buf) | |
90 | return NULL; | |
91 | ret = pread(root->fp, &buf->node, CTREE_BLOCKSIZE, offset); | |
92 | if (ret != CTREE_BLOCKSIZE) { | |
93 | free(buf); | |
94 | return NULL; | |
95 | } | |
96 | if (buf->blocknr != buf->node.header.blocknr) | |
97 | BUG(); | |
98 | return buf; | |
99 | } | |
100 | ||
101 | int write_tree_block(struct ctree_root *root, struct tree_buffer *buf) | |
102 | { | |
103 | u64 blocknr = buf->blocknr; | |
104 | loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header); | |
105 | int ret; | |
106 | ||
107 | if (buf->blocknr != buf->node.header.blocknr) | |
108 | BUG(); | |
109 | ret = pwrite(root->fp, &buf->node, CTREE_BLOCKSIZE, offset); | |
110 | if (ret != CTREE_BLOCKSIZE) | |
111 | return ret; | |
112 | if (buf == root->node) | |
113 | return update_root_block(root); | |
114 | return 0; | |
115 | } | |
116 | ||
117 | struct ctree_root *open_ctree(char *filename) | |
118 | { | |
119 | struct ctree_root *root = malloc(sizeof(struct ctree_root)); | |
120 | int fp; | |
121 | u64 root_block; | |
122 | int ret; | |
123 | ||
124 | fp = open(filename, O_CREAT | O_RDWR); | |
125 | if (fp < 0) { | |
126 | free(root); | |
127 | return NULL; | |
128 | } | |
129 | root->fp = fp; | |
130 | INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL); | |
131 | ret = pread(fp, &root_block, sizeof(u64), 0); | |
132 | if (ret == sizeof(u64)) { | |
133 | printf("reading root node at block %lu\n", root_block); | |
134 | root->node = read_tree_block(root, root_block); | |
135 | } else | |
136 | root->node = NULL; | |
137 | return root; | |
138 | } | |
139 | ||
140 | int close_ctree(struct ctree_root *root) | |
141 | { | |
142 | close(root->fp); | |
143 | if (root->node) | |
144 | tree_block_release(root, root->node); | |
145 | free(root); | |
146 | printf("on close %d blocks are allocated\n", allocated_blocks); | |
147 | return 0; | |
148 | } | |
149 | ||
150 | int update_root_block(struct ctree_root *root) | |
151 | { | |
152 | int ret; | |
153 | u64 root_block = root->node->blocknr; | |
154 | ||
155 | ret = pwrite(root->fp, &root_block, sizeof(u64), 0); | |
156 | if (ret != sizeof(u64)) | |
157 | return ret; | |
158 | return 0; | |
159 | } | |
160 | ||
161 | void tree_block_release(struct ctree_root *root, struct tree_buffer *buf) | |
162 | { | |
163 | buf->count--; | |
164 | if (buf->count == 0) { | |
165 | if (!radix_tree_lookup(&root->cache_radix, buf->blocknr)) | |
166 | BUG(); | |
167 | radix_tree_delete(&root->cache_radix, buf->blocknr); | |
168 | memset(buf, 0, sizeof(*buf)); | |
169 | free(buf); | |
170 | BUG_ON(allocated_blocks == 0); | |
171 | allocated_blocks--; | |
172 | } | |
173 | } | |
174 |