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1da177e4 LT |
1 | /* |
2 | * linux/fs/hfsplus/btree.c | |
3 | * | |
4 | * Copyright (C) 2001 | |
5 | * Brad Boyer (flar@allandria.com) | |
6 | * (C) 2003 Ardis Technologies <roman@ardistech.com> | |
7 | * | |
8 | * Handle opening/closing btree | |
9 | */ | |
10 | ||
11 | #include <linux/slab.h> | |
12 | #include <linux/pagemap.h> | |
13 | ||
14 | #include "hfsplus_fs.h" | |
15 | #include "hfsplus_raw.h" | |
16 | ||
17 | ||
18 | /* Get a reference to a B*Tree and do some initial checks */ | |
19 | struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id) | |
20 | { | |
21 | struct hfs_btree *tree; | |
22 | struct hfs_btree_header_rec *head; | |
23 | struct address_space *mapping; | |
24 | struct page *page; | |
25 | unsigned int size; | |
26 | ||
27 | tree = kmalloc(sizeof(*tree), GFP_KERNEL); | |
28 | if (!tree) | |
29 | return NULL; | |
30 | memset(tree, 0, sizeof(*tree)); | |
31 | ||
32 | init_MUTEX(&tree->tree_lock); | |
33 | spin_lock_init(&tree->hash_lock); | |
34 | /* Set the correct compare function */ | |
35 | tree->sb = sb; | |
36 | tree->cnid = id; | |
37 | if (id == HFSPLUS_EXT_CNID) { | |
38 | tree->keycmp = hfsplus_ext_cmp_key; | |
39 | } else if (id == HFSPLUS_CAT_CNID) { | |
40 | tree->keycmp = hfsplus_cat_cmp_key; | |
41 | } else { | |
634725a9 | 42 | printk(KERN_ERR "hfs: unknown B*Tree requested\n"); |
1da177e4 LT |
43 | goto free_tree; |
44 | } | |
45 | tree->inode = iget(sb, id); | |
46 | if (!tree->inode) | |
47 | goto free_tree; | |
48 | ||
49 | mapping = tree->inode->i_mapping; | |
50 | page = read_cache_page(mapping, 0, (filler_t *)mapping->a_ops->readpage, NULL); | |
51 | if (IS_ERR(page)) | |
52 | goto free_tree; | |
53 | ||
54 | /* Load the header */ | |
55 | head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); | |
56 | tree->root = be32_to_cpu(head->root); | |
57 | tree->leaf_count = be32_to_cpu(head->leaf_count); | |
58 | tree->leaf_head = be32_to_cpu(head->leaf_head); | |
59 | tree->leaf_tail = be32_to_cpu(head->leaf_tail); | |
60 | tree->node_count = be32_to_cpu(head->node_count); | |
61 | tree->free_nodes = be32_to_cpu(head->free_nodes); | |
62 | tree->attributes = be32_to_cpu(head->attributes); | |
63 | tree->node_size = be16_to_cpu(head->node_size); | |
64 | tree->max_key_len = be16_to_cpu(head->max_key_len); | |
65 | tree->depth = be16_to_cpu(head->depth); | |
66 | ||
67 | size = tree->node_size; | |
68 | if (!size || size & (size - 1)) | |
69 | goto fail_page; | |
70 | if (!tree->node_count) | |
71 | goto fail_page; | |
72 | tree->node_size_shift = ffs(size) - 1; | |
73 | ||
74 | tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
75 | ||
76 | kunmap(page); | |
77 | page_cache_release(page); | |
78 | return tree; | |
79 | ||
80 | fail_page: | |
81 | tree->inode->i_mapping->a_ops = &hfsplus_aops; | |
82 | page_cache_release(page); | |
83 | free_tree: | |
84 | iput(tree->inode); | |
85 | kfree(tree); | |
86 | return NULL; | |
87 | } | |
88 | ||
89 | /* Release resources used by a btree */ | |
90 | void hfs_btree_close(struct hfs_btree *tree) | |
91 | { | |
92 | struct hfs_bnode *node; | |
93 | int i; | |
94 | ||
95 | if (!tree) | |
96 | return; | |
97 | ||
98 | for (i = 0; i < NODE_HASH_SIZE; i++) { | |
99 | while ((node = tree->node_hash[i])) { | |
100 | tree->node_hash[i] = node->next_hash; | |
101 | if (atomic_read(&node->refcnt)) | |
634725a9 | 102 | printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n", |
1da177e4 LT |
103 | node->tree->cnid, node->this, atomic_read(&node->refcnt)); |
104 | hfs_bnode_free(node); | |
105 | tree->node_hash_cnt--; | |
106 | } | |
107 | } | |
108 | iput(tree->inode); | |
109 | kfree(tree); | |
110 | } | |
111 | ||
112 | void hfs_btree_write(struct hfs_btree *tree) | |
113 | { | |
114 | struct hfs_btree_header_rec *head; | |
115 | struct hfs_bnode *node; | |
116 | struct page *page; | |
117 | ||
118 | node = hfs_bnode_find(tree, 0); | |
119 | if (IS_ERR(node)) | |
120 | /* panic? */ | |
121 | return; | |
122 | /* Load the header */ | |
123 | page = node->page[0]; | |
124 | head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); | |
125 | ||
126 | head->root = cpu_to_be32(tree->root); | |
127 | head->leaf_count = cpu_to_be32(tree->leaf_count); | |
128 | head->leaf_head = cpu_to_be32(tree->leaf_head); | |
129 | head->leaf_tail = cpu_to_be32(tree->leaf_tail); | |
130 | head->node_count = cpu_to_be32(tree->node_count); | |
131 | head->free_nodes = cpu_to_be32(tree->free_nodes); | |
132 | head->attributes = cpu_to_be32(tree->attributes); | |
133 | head->depth = cpu_to_be16(tree->depth); | |
134 | ||
135 | kunmap(page); | |
136 | set_page_dirty(page); | |
137 | hfs_bnode_put(node); | |
138 | } | |
139 | ||
140 | static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) | |
141 | { | |
142 | struct hfs_btree *tree = prev->tree; | |
143 | struct hfs_bnode *node; | |
144 | struct hfs_bnode_desc desc; | |
145 | __be32 cnid; | |
146 | ||
147 | node = hfs_bnode_create(tree, idx); | |
148 | if (IS_ERR(node)) | |
149 | return node; | |
150 | ||
151 | tree->free_nodes--; | |
152 | prev->next = idx; | |
153 | cnid = cpu_to_be32(idx); | |
154 | hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); | |
155 | ||
156 | node->type = HFS_NODE_MAP; | |
157 | node->num_recs = 1; | |
158 | hfs_bnode_clear(node, 0, tree->node_size); | |
159 | desc.next = 0; | |
160 | desc.prev = 0; | |
161 | desc.type = HFS_NODE_MAP; | |
162 | desc.height = 0; | |
163 | desc.num_recs = cpu_to_be16(1); | |
164 | desc.reserved = 0; | |
165 | hfs_bnode_write(node, &desc, 0, sizeof(desc)); | |
166 | hfs_bnode_write_u16(node, 14, 0x8000); | |
167 | hfs_bnode_write_u16(node, tree->node_size - 2, 14); | |
168 | hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); | |
169 | ||
170 | return node; | |
171 | } | |
172 | ||
173 | struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) | |
174 | { | |
175 | struct hfs_bnode *node, *next_node; | |
176 | struct page **pagep; | |
177 | u32 nidx, idx; | |
178 | u16 off, len; | |
179 | u8 *data, byte, m; | |
180 | int i; | |
181 | ||
182 | while (!tree->free_nodes) { | |
183 | struct inode *inode = tree->inode; | |
184 | u32 count; | |
185 | int res; | |
186 | ||
187 | res = hfsplus_file_extend(inode); | |
188 | if (res) | |
189 | return ERR_PTR(res); | |
190 | HFSPLUS_I(inode).phys_size = inode->i_size = | |
191 | (loff_t)HFSPLUS_I(inode).alloc_blocks << | |
192 | HFSPLUS_SB(tree->sb).alloc_blksz_shift; | |
193 | HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks << | |
194 | HFSPLUS_SB(tree->sb).fs_shift; | |
195 | inode_set_bytes(inode, inode->i_size); | |
196 | count = inode->i_size >> tree->node_size_shift; | |
197 | tree->free_nodes = count - tree->node_count; | |
198 | tree->node_count = count; | |
199 | } | |
200 | ||
201 | nidx = 0; | |
202 | node = hfs_bnode_find(tree, nidx); | |
203 | if (IS_ERR(node)) | |
204 | return node; | |
205 | len = hfs_brec_lenoff(node, 2, &off); | |
206 | ||
207 | off += node->page_offset; | |
208 | pagep = node->page + (off >> PAGE_CACHE_SHIFT); | |
209 | data = kmap(*pagep); | |
210 | off &= ~PAGE_CACHE_MASK; | |
211 | idx = 0; | |
212 | ||
213 | for (;;) { | |
214 | while (len) { | |
215 | byte = data[off]; | |
216 | if (byte != 0xff) { | |
217 | for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { | |
218 | if (!(byte & m)) { | |
219 | idx += i; | |
220 | data[off] |= m; | |
221 | set_page_dirty(*pagep); | |
222 | kunmap(*pagep); | |
223 | tree->free_nodes--; | |
224 | mark_inode_dirty(tree->inode); | |
225 | hfs_bnode_put(node); | |
1da177e4 LT |
226 | return hfs_bnode_create(tree, idx); |
227 | } | |
228 | } | |
229 | } | |
230 | if (++off >= PAGE_CACHE_SIZE) { | |
231 | kunmap(*pagep); | |
232 | data = kmap(*++pagep); | |
233 | off = 0; | |
234 | } | |
235 | idx += 8; | |
236 | len--; | |
237 | } | |
238 | kunmap(*pagep); | |
239 | nidx = node->next; | |
240 | if (!nidx) { | |
634725a9 | 241 | printk(KERN_DEBUG "hfs: create new bmap node...\n"); |
1da177e4 LT |
242 | next_node = hfs_bmap_new_bmap(node, idx); |
243 | } else | |
244 | next_node = hfs_bnode_find(tree, nidx); | |
245 | hfs_bnode_put(node); | |
246 | if (IS_ERR(next_node)) | |
247 | return next_node; | |
248 | node = next_node; | |
249 | ||
250 | len = hfs_brec_lenoff(node, 0, &off); | |
251 | off += node->page_offset; | |
252 | pagep = node->page + (off >> PAGE_CACHE_SHIFT); | |
253 | data = kmap(*pagep); | |
254 | off &= ~PAGE_CACHE_MASK; | |
255 | } | |
256 | } | |
257 | ||
258 | void hfs_bmap_free(struct hfs_bnode *node) | |
259 | { | |
260 | struct hfs_btree *tree; | |
261 | struct page *page; | |
262 | u16 off, len; | |
263 | u32 nidx; | |
264 | u8 *data, byte, m; | |
265 | ||
266 | dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); | |
267 | if (!node->this) | |
268 | BUG(); | |
269 | tree = node->tree; | |
270 | nidx = node->this; | |
271 | node = hfs_bnode_find(tree, 0); | |
272 | if (IS_ERR(node)) | |
273 | return; | |
274 | len = hfs_brec_lenoff(node, 2, &off); | |
275 | while (nidx >= len * 8) { | |
276 | u32 i; | |
277 | ||
278 | nidx -= len * 8; | |
279 | i = node->next; | |
280 | hfs_bnode_put(node); | |
281 | if (!i) { | |
282 | /* panic */; | |
634725a9 | 283 | printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); |
1da177e4 LT |
284 | return; |
285 | } | |
286 | node = hfs_bnode_find(tree, i); | |
287 | if (IS_ERR(node)) | |
288 | return; | |
289 | if (node->type != HFS_NODE_MAP) { | |
290 | /* panic */; | |
634725a9 | 291 | printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); |
1da177e4 LT |
292 | hfs_bnode_put(node); |
293 | return; | |
294 | } | |
295 | len = hfs_brec_lenoff(node, 0, &off); | |
296 | } | |
297 | off += node->page_offset + nidx / 8; | |
298 | page = node->page[off >> PAGE_CACHE_SHIFT]; | |
299 | data = kmap(page); | |
300 | off &= ~PAGE_CACHE_MASK; | |
301 | m = 1 << (~nidx & 7); | |
302 | byte = data[off]; | |
303 | if (!(byte & m)) { | |
634725a9 | 304 | printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); |
1da177e4 LT |
305 | kunmap(page); |
306 | hfs_bnode_put(node); | |
307 | return; | |
308 | } | |
309 | data[off] = byte & ~m; | |
310 | set_page_dirty(page); | |
311 | kunmap(page); | |
312 | hfs_bnode_put(node); | |
313 | tree->free_nodes++; | |
314 | mark_inode_dirty(tree->inode); | |
315 | } |