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1 | /* |
2 | * linux/fs/hfs/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/pagemap.h> |
12 | #include <linux/slab.h> |
13 | #include <linux/log2.h> |
14 | |
15 | #include "btree.h" |
16 | |
17 | /* Get a reference to a B*Tree and do some initial checks */ |
18 | struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp) |
19 | { |
20 | struct hfs_btree *tree; |
21 | struct hfs_btree_header_rec *head; |
22 | struct address_space *mapping; |
23 | struct page *page; |
24 | unsigned int size; |
25 | |
26 | tree = kzalloc(sizeof(*tree), GFP_KERNEL); |
27 | if (!tree) |
28 | return NULL; |
29 | |
30 | mutex_init(&tree->tree_lock); |
31 | spin_lock_init(&tree->hash_lock); |
32 | /* Set the correct compare function */ |
33 | tree->sb = sb; |
34 | tree->cnid = id; |
35 | tree->keycmp = keycmp; |
36 | |
37 | tree->inode = iget_locked(sb, id); |
38 | if (!tree->inode) |
39 | goto free_tree; |
40 | BUG_ON(!(tree->inode->i_state & I_NEW)); |
41 | { |
42 | struct hfs_mdb *mdb = HFS_SB(sb)->mdb; |
43 | HFS_I(tree->inode)->flags = 0; |
44 | mutex_init(&HFS_I(tree->inode)->extents_lock); |
45 | switch (id) { |
46 | case HFS_EXT_CNID: |
47 | hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize, |
48 | mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz)); |
49 | tree->inode->i_mapping->a_ops = &hfs_btree_aops; |
50 | break; |
51 | case HFS_CAT_CNID: |
52 | hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize, |
53 | mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz)); |
54 | tree->inode->i_mapping->a_ops = &hfs_btree_aops; |
55 | break; |
56 | default: |
57 | BUG(); |
58 | } |
59 | } |
60 | unlock_new_inode(tree->inode); |
61 | |
62 | if (!HFS_I(tree->inode)->first_blocks) { |
63 | printk(KERN_ERR "hfs: invalid btree extent records (0 size).\n"); |
64 | goto free_inode; |
65 | } |
66 | |
67 | mapping = tree->inode->i_mapping; |
68 | page = read_mapping_page(mapping, 0, NULL); |
69 | if (IS_ERR(page)) |
70 | goto free_inode; |
71 | |
72 | /* Load the header */ |
73 | head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); |
74 | tree->root = be32_to_cpu(head->root); |
75 | tree->leaf_count = be32_to_cpu(head->leaf_count); |
76 | tree->leaf_head = be32_to_cpu(head->leaf_head); |
77 | tree->leaf_tail = be32_to_cpu(head->leaf_tail); |
78 | tree->node_count = be32_to_cpu(head->node_count); |
79 | tree->free_nodes = be32_to_cpu(head->free_nodes); |
80 | tree->attributes = be32_to_cpu(head->attributes); |
81 | tree->node_size = be16_to_cpu(head->node_size); |
82 | tree->max_key_len = be16_to_cpu(head->max_key_len); |
83 | tree->depth = be16_to_cpu(head->depth); |
84 | |
85 | size = tree->node_size; |
86 | if (!is_power_of_2(size)) |
87 | goto fail_page; |
88 | if (!tree->node_count) |
89 | goto fail_page; |
90 | switch (id) { |
91 | case HFS_EXT_CNID: |
92 | if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) { |
93 | printk(KERN_ERR "hfs: invalid extent max_key_len %d\n", |
94 | tree->max_key_len); |
95 | goto fail_page; |
96 | } |
97 | break; |
98 | case HFS_CAT_CNID: |
99 | if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) { |
100 | printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n", |
101 | tree->max_key_len); |
102 | goto fail_page; |
103 | } |
104 | break; |
105 | default: |
106 | BUG(); |
107 | } |
108 | |
109 | tree->node_size_shift = ffs(size) - 1; |
110 | tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
111 | |
112 | kunmap(page); |
113 | page_cache_release(page); |
114 | return tree; |
115 | |
116 | fail_page: |
117 | page_cache_release(page); |
118 | free_inode: |
119 | tree->inode->i_mapping->a_ops = &hfs_aops; |
120 | iput(tree->inode); |
121 | free_tree: |
122 | kfree(tree); |
123 | return NULL; |
124 | } |
125 | |
126 | /* Release resources used by a btree */ |
127 | void hfs_btree_close(struct hfs_btree *tree) |
128 | { |
129 | struct hfs_bnode *node; |
130 | int i; |
131 | |
132 | if (!tree) |
133 | return; |
134 | |
135 | for (i = 0; i < NODE_HASH_SIZE; i++) { |
136 | while ((node = tree->node_hash[i])) { |
137 | tree->node_hash[i] = node->next_hash; |
138 | if (atomic_read(&node->refcnt)) |
139 | printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n", |
140 | node->tree->cnid, node->this, atomic_read(&node->refcnt)); |
141 | hfs_bnode_free(node); |
142 | tree->node_hash_cnt--; |
143 | } |
144 | } |
145 | iput(tree->inode); |
146 | kfree(tree); |
147 | } |
148 | |
149 | void hfs_btree_write(struct hfs_btree *tree) |
150 | { |
151 | struct hfs_btree_header_rec *head; |
152 | struct hfs_bnode *node; |
153 | struct page *page; |
154 | |
155 | node = hfs_bnode_find(tree, 0); |
156 | if (IS_ERR(node)) |
157 | /* panic? */ |
158 | return; |
159 | /* Load the header */ |
160 | page = node->page[0]; |
161 | head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); |
162 | |
163 | head->root = cpu_to_be32(tree->root); |
164 | head->leaf_count = cpu_to_be32(tree->leaf_count); |
165 | head->leaf_head = cpu_to_be32(tree->leaf_head); |
166 | head->leaf_tail = cpu_to_be32(tree->leaf_tail); |
167 | head->node_count = cpu_to_be32(tree->node_count); |
168 | head->free_nodes = cpu_to_be32(tree->free_nodes); |
169 | head->attributes = cpu_to_be32(tree->attributes); |
170 | head->depth = cpu_to_be16(tree->depth); |
171 | |
172 | kunmap(page); |
173 | set_page_dirty(page); |
174 | hfs_bnode_put(node); |
175 | } |
176 | |
177 | static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) |
178 | { |
179 | struct hfs_btree *tree = prev->tree; |
180 | struct hfs_bnode *node; |
181 | struct hfs_bnode_desc desc; |
182 | __be32 cnid; |
183 | |
184 | node = hfs_bnode_create(tree, idx); |
185 | if (IS_ERR(node)) |
186 | return node; |
187 | |
188 | if (!tree->free_nodes) |
189 | panic("FIXME!!!"); |
190 | tree->free_nodes--; |
191 | prev->next = idx; |
192 | cnid = cpu_to_be32(idx); |
193 | hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); |
194 | |
195 | node->type = HFS_NODE_MAP; |
196 | node->num_recs = 1; |
197 | hfs_bnode_clear(node, 0, tree->node_size); |
198 | desc.next = 0; |
199 | desc.prev = 0; |
200 | desc.type = HFS_NODE_MAP; |
201 | desc.height = 0; |
202 | desc.num_recs = cpu_to_be16(1); |
203 | desc.reserved = 0; |
204 | hfs_bnode_write(node, &desc, 0, sizeof(desc)); |
205 | hfs_bnode_write_u16(node, 14, 0x8000); |
206 | hfs_bnode_write_u16(node, tree->node_size - 2, 14); |
207 | hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); |
208 | |
209 | return node; |
210 | } |
211 | |
212 | struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) |
213 | { |
214 | struct hfs_bnode *node, *next_node; |
215 | struct page **pagep; |
216 | u32 nidx, idx; |
217 | unsigned off; |
218 | u16 off16; |
219 | u16 len; |
220 | u8 *data, byte, m; |
221 | int i; |
222 | |
223 | while (!tree->free_nodes) { |
224 | struct inode *inode = tree->inode; |
225 | u32 count; |
226 | int res; |
227 | |
228 | res = hfs_extend_file(inode); |
229 | if (res) |
230 | return ERR_PTR(res); |
231 | HFS_I(inode)->phys_size = inode->i_size = |
232 | (loff_t)HFS_I(inode)->alloc_blocks * |
233 | HFS_SB(tree->sb)->alloc_blksz; |
234 | HFS_I(inode)->fs_blocks = inode->i_size >> |
235 | tree->sb->s_blocksize_bits; |
236 | inode_set_bytes(inode, inode->i_size); |
237 | count = inode->i_size >> tree->node_size_shift; |
238 | tree->free_nodes = count - tree->node_count; |
239 | tree->node_count = count; |
240 | } |
241 | |
242 | nidx = 0; |
243 | node = hfs_bnode_find(tree, nidx); |
244 | if (IS_ERR(node)) |
245 | return node; |
246 | len = hfs_brec_lenoff(node, 2, &off16); |
247 | off = off16; |
248 | |
249 | off += node->page_offset; |
250 | pagep = node->page + (off >> PAGE_CACHE_SHIFT); |
251 | data = kmap(*pagep); |
252 | off &= ~PAGE_CACHE_MASK; |
253 | idx = 0; |
254 | |
255 | for (;;) { |
256 | while (len) { |
257 | byte = data[off]; |
258 | if (byte != 0xff) { |
259 | for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { |
260 | if (!(byte & m)) { |
261 | idx += i; |
262 | data[off] |= m; |
263 | set_page_dirty(*pagep); |
264 | kunmap(*pagep); |
265 | tree->free_nodes--; |
266 | mark_inode_dirty(tree->inode); |
267 | hfs_bnode_put(node); |
268 | return hfs_bnode_create(tree, idx); |
269 | } |
270 | } |
271 | } |
272 | if (++off >= PAGE_CACHE_SIZE) { |
273 | kunmap(*pagep); |
274 | data = kmap(*++pagep); |
275 | off = 0; |
276 | } |
277 | idx += 8; |
278 | len--; |
279 | } |
280 | kunmap(*pagep); |
281 | nidx = node->next; |
282 | if (!nidx) { |
283 | printk(KERN_DEBUG "hfs: create new bmap node...\n"); |
284 | next_node = hfs_bmap_new_bmap(node, idx); |
285 | } else |
286 | next_node = hfs_bnode_find(tree, nidx); |
287 | hfs_bnode_put(node); |
288 | if (IS_ERR(next_node)) |
289 | return next_node; |
290 | node = next_node; |
291 | |
292 | len = hfs_brec_lenoff(node, 0, &off16); |
293 | off = off16; |
294 | off += node->page_offset; |
295 | pagep = node->page + (off >> PAGE_CACHE_SHIFT); |
296 | data = kmap(*pagep); |
297 | off &= ~PAGE_CACHE_MASK; |
298 | } |
299 | } |
300 | |
301 | void hfs_bmap_free(struct hfs_bnode *node) |
302 | { |
303 | struct hfs_btree *tree; |
304 | struct page *page; |
305 | u16 off, len; |
306 | u32 nidx; |
307 | u8 *data, byte, m; |
308 | |
309 | dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); |
310 | tree = node->tree; |
311 | nidx = node->this; |
312 | node = hfs_bnode_find(tree, 0); |
313 | if (IS_ERR(node)) |
314 | return; |
315 | len = hfs_brec_lenoff(node, 2, &off); |
316 | while (nidx >= len * 8) { |
317 | u32 i; |
318 | |
319 | nidx -= len * 8; |
320 | i = node->next; |
321 | hfs_bnode_put(node); |
322 | if (!i) { |
323 | /* panic */; |
324 | printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); |
325 | return; |
326 | } |
327 | node = hfs_bnode_find(tree, i); |
328 | if (IS_ERR(node)) |
329 | return; |
330 | if (node->type != HFS_NODE_MAP) { |
331 | /* panic */; |
332 | printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); |
333 | hfs_bnode_put(node); |
334 | return; |
335 | } |
336 | len = hfs_brec_lenoff(node, 0, &off); |
337 | } |
338 | off += node->page_offset + nidx / 8; |
339 | page = node->page[off >> PAGE_CACHE_SHIFT]; |
340 | data = kmap(page); |
341 | off &= ~PAGE_CACHE_MASK; |
342 | m = 1 << (~nidx & 7); |
343 | byte = data[off]; |
344 | if (!(byte & m)) { |
345 | printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); |
346 | kunmap(page); |
347 | hfs_bnode_put(node); |
348 | return; |
349 | } |
350 | data[off] = byte & ~m; |
351 | set_page_dirty(page); |
352 | kunmap(page); |
353 | hfs_bnode_put(node); |
354 | tree->free_nodes++; |
355 | mark_inode_dirty(tree->inode); |
356 | } |
357 |
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