Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/hfs/bnode.c | |
3 | * | |
4 | * Copyright (C) 2001 | |
5 | * Brad Boyer (flar@allandria.com) | |
6 | * (C) 2003 Ardis Technologies <roman@ardistech.com> | |
7 | * | |
8 | * Handle basic btree node operations | |
9 | */ | |
10 | ||
11 | #include <linux/pagemap.h> | |
12 | #include <linux/swap.h> | |
13 | ||
14 | #include "btree.h" | |
15 | ||
16 | #define REF_PAGES 0 | |
17 | ||
18 | void hfs_bnode_read(struct hfs_bnode *node, void *buf, | |
19 | int off, int len) | |
20 | { | |
21 | struct page *page; | |
22 | ||
23 | off += node->page_offset; | |
24 | page = node->page[0]; | |
25 | ||
26 | memcpy(buf, kmap(page) + off, len); | |
27 | kunmap(page); | |
28 | } | |
29 | ||
30 | u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off) | |
31 | { | |
32 | __be16 data; | |
33 | // optimize later... | |
34 | hfs_bnode_read(node, &data, off, 2); | |
35 | return be16_to_cpu(data); | |
36 | } | |
37 | ||
38 | u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off) | |
39 | { | |
40 | u8 data; | |
41 | // optimize later... | |
42 | hfs_bnode_read(node, &data, off, 1); | |
43 | return data; | |
44 | } | |
45 | ||
46 | void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off) | |
47 | { | |
48 | struct hfs_btree *tree; | |
49 | int key_len; | |
50 | ||
51 | tree = node->tree; | |
52 | if (node->type == HFS_NODE_LEAF || | |
53 | tree->attributes & HFS_TREE_VARIDXKEYS) | |
54 | key_len = hfs_bnode_read_u8(node, off) + 1; | |
55 | else | |
56 | key_len = tree->max_key_len + 1; | |
57 | ||
58 | hfs_bnode_read(node, key, off, key_len); | |
59 | } | |
60 | ||
61 | void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len) | |
62 | { | |
63 | struct page *page; | |
64 | ||
65 | off += node->page_offset; | |
66 | page = node->page[0]; | |
67 | ||
68 | memcpy(kmap(page) + off, buf, len); | |
69 | kunmap(page); | |
70 | set_page_dirty(page); | |
71 | } | |
72 | ||
73 | void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data) | |
74 | { | |
75 | __be16 v = cpu_to_be16(data); | |
76 | // optimize later... | |
77 | hfs_bnode_write(node, &v, off, 2); | |
78 | } | |
79 | ||
80 | void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data) | |
81 | { | |
82 | // optimize later... | |
83 | hfs_bnode_write(node, &data, off, 1); | |
84 | } | |
85 | ||
86 | void hfs_bnode_clear(struct hfs_bnode *node, int off, int len) | |
87 | { | |
88 | struct page *page; | |
89 | ||
90 | off += node->page_offset; | |
91 | page = node->page[0]; | |
92 | ||
93 | memset(kmap(page) + off, 0, len); | |
94 | kunmap(page); | |
95 | set_page_dirty(page); | |
96 | } | |
97 | ||
98 | void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst, | |
99 | struct hfs_bnode *src_node, int src, int len) | |
100 | { | |
101 | struct hfs_btree *tree; | |
102 | struct page *src_page, *dst_page; | |
103 | ||
104 | dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len); | |
105 | if (!len) | |
106 | return; | |
107 | tree = src_node->tree; | |
108 | src += src_node->page_offset; | |
109 | dst += dst_node->page_offset; | |
110 | src_page = src_node->page[0]; | |
111 | dst_page = dst_node->page[0]; | |
112 | ||
113 | memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len); | |
114 | kunmap(src_page); | |
115 | kunmap(dst_page); | |
116 | set_page_dirty(dst_page); | |
117 | } | |
118 | ||
119 | void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len) | |
120 | { | |
121 | struct page *page; | |
122 | void *ptr; | |
123 | ||
124 | dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len); | |
125 | if (!len) | |
126 | return; | |
127 | src += node->page_offset; | |
128 | dst += node->page_offset; | |
129 | page = node->page[0]; | |
130 | ptr = kmap(page); | |
131 | memmove(ptr + dst, ptr + src, len); | |
132 | kunmap(page); | |
133 | set_page_dirty(page); | |
134 | } | |
135 | ||
136 | void hfs_bnode_dump(struct hfs_bnode *node) | |
137 | { | |
138 | struct hfs_bnode_desc desc; | |
139 | __be32 cnid; | |
140 | int i, off, key_off; | |
141 | ||
142 | dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this); | |
143 | hfs_bnode_read(node, &desc, 0, sizeof(desc)); | |
144 | dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n", | |
145 | be32_to_cpu(desc.next), be32_to_cpu(desc.prev), | |
146 | desc.type, desc.height, be16_to_cpu(desc.num_recs)); | |
147 | ||
148 | off = node->tree->node_size - 2; | |
149 | for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) { | |
150 | key_off = hfs_bnode_read_u16(node, off); | |
151 | dprint(DBG_BNODE_MOD, " %d", key_off); | |
152 | if (i && node->type == HFS_NODE_INDEX) { | |
153 | int tmp; | |
154 | ||
155 | if (node->tree->attributes & HFS_TREE_VARIDXKEYS) | |
156 | tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1; | |
157 | else | |
158 | tmp = node->tree->max_key_len + 1; | |
159 | dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off)); | |
160 | hfs_bnode_read(node, &cnid, key_off + tmp, 4); | |
161 | dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid)); | |
162 | } else if (i && node->type == HFS_NODE_LEAF) { | |
163 | int tmp; | |
164 | ||
165 | tmp = hfs_bnode_read_u8(node, key_off); | |
166 | dprint(DBG_BNODE_MOD, " (%d)", tmp); | |
167 | } | |
168 | } | |
169 | dprint(DBG_BNODE_MOD, "\n"); | |
170 | } | |
171 | ||
172 | void hfs_bnode_unlink(struct hfs_bnode *node) | |
173 | { | |
174 | struct hfs_btree *tree; | |
175 | struct hfs_bnode *tmp; | |
176 | __be32 cnid; | |
177 | ||
178 | tree = node->tree; | |
179 | if (node->prev) { | |
180 | tmp = hfs_bnode_find(tree, node->prev); | |
181 | if (IS_ERR(tmp)) | |
182 | return; | |
183 | tmp->next = node->next; | |
184 | cnid = cpu_to_be32(tmp->next); | |
185 | hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4); | |
186 | hfs_bnode_put(tmp); | |
187 | } else if (node->type == HFS_NODE_LEAF) | |
188 | tree->leaf_head = node->next; | |
189 | ||
190 | if (node->next) { | |
191 | tmp = hfs_bnode_find(tree, node->next); | |
192 | if (IS_ERR(tmp)) | |
193 | return; | |
194 | tmp->prev = node->prev; | |
195 | cnid = cpu_to_be32(tmp->prev); | |
196 | hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4); | |
197 | hfs_bnode_put(tmp); | |
198 | } else if (node->type == HFS_NODE_LEAF) | |
199 | tree->leaf_tail = node->prev; | |
200 | ||
201 | // move down? | |
202 | if (!node->prev && !node->next) { | |
203 | printk("hfs_btree_del_level\n"); | |
204 | } | |
205 | if (!node->parent) { | |
206 | tree->root = 0; | |
207 | tree->depth = 0; | |
208 | } | |
209 | set_bit(HFS_BNODE_DELETED, &node->flags); | |
210 | } | |
211 | ||
212 | static inline int hfs_bnode_hash(u32 num) | |
213 | { | |
214 | num = (num >> 16) + num; | |
215 | num += num >> 8; | |
216 | return num & (NODE_HASH_SIZE - 1); | |
217 | } | |
218 | ||
219 | struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid) | |
220 | { | |
221 | struct hfs_bnode *node; | |
222 | ||
223 | if (cnid >= tree->node_count) { | |
224 | printk("HFS: request for non-existent node %d in B*Tree\n", cnid); | |
225 | return NULL; | |
226 | } | |
227 | ||
228 | for (node = tree->node_hash[hfs_bnode_hash(cnid)]; | |
229 | node; node = node->next_hash) { | |
230 | if (node->this == cnid) { | |
231 | return node; | |
232 | } | |
233 | } | |
234 | return NULL; | |
235 | } | |
236 | ||
237 | static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid) | |
238 | { | |
239 | struct super_block *sb; | |
240 | struct hfs_bnode *node, *node2; | |
241 | struct address_space *mapping; | |
242 | struct page *page; | |
243 | int size, block, i, hash; | |
244 | loff_t off; | |
245 | ||
246 | if (cnid >= tree->node_count) { | |
247 | printk("HFS: request for non-existent node %d in B*Tree\n", cnid); | |
248 | return NULL; | |
249 | } | |
250 | ||
251 | sb = tree->inode->i_sb; | |
252 | size = sizeof(struct hfs_bnode) + tree->pages_per_bnode * | |
253 | sizeof(struct page *); | |
254 | node = kmalloc(size, GFP_KERNEL); | |
255 | if (!node) | |
256 | return NULL; | |
257 | memset(node, 0, size); | |
258 | node->tree = tree; | |
259 | node->this = cnid; | |
260 | set_bit(HFS_BNODE_NEW, &node->flags); | |
261 | atomic_set(&node->refcnt, 1); | |
262 | dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n", | |
263 | node->tree->cnid, node->this); | |
264 | init_waitqueue_head(&node->lock_wq); | |
265 | spin_lock(&tree->hash_lock); | |
266 | node2 = hfs_bnode_findhash(tree, cnid); | |
267 | if (!node2) { | |
268 | hash = hfs_bnode_hash(cnid); | |
269 | node->next_hash = tree->node_hash[hash]; | |
270 | tree->node_hash[hash] = node; | |
271 | tree->node_hash_cnt++; | |
272 | } else { | |
273 | spin_unlock(&tree->hash_lock); | |
274 | kfree(node); | |
275 | wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags)); | |
276 | return node2; | |
277 | } | |
278 | spin_unlock(&tree->hash_lock); | |
279 | ||
280 | mapping = tree->inode->i_mapping; | |
281 | off = (loff_t)cnid * tree->node_size; | |
282 | block = off >> PAGE_CACHE_SHIFT; | |
283 | node->page_offset = off & ~PAGE_CACHE_MASK; | |
284 | for (i = 0; i < tree->pages_per_bnode; i++) { | |
285 | page = read_cache_page(mapping, block++, (filler_t *)mapping->a_ops->readpage, NULL); | |
286 | if (IS_ERR(page)) | |
287 | goto fail; | |
288 | if (PageError(page)) { | |
289 | page_cache_release(page); | |
290 | goto fail; | |
291 | } | |
292 | #if !REF_PAGES | |
293 | page_cache_release(page); | |
294 | #endif | |
295 | node->page[i] = page; | |
296 | } | |
297 | ||
298 | return node; | |
299 | fail: | |
300 | set_bit(HFS_BNODE_ERROR, &node->flags); | |
301 | return node; | |
302 | } | |
303 | ||
304 | void hfs_bnode_unhash(struct hfs_bnode *node) | |
305 | { | |
306 | struct hfs_bnode **p; | |
307 | ||
308 | dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n", | |
309 | node->tree->cnid, node->this, atomic_read(&node->refcnt)); | |
310 | for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)]; | |
311 | *p && *p != node; p = &(*p)->next_hash) | |
312 | ; | |
313 | if (!*p) | |
314 | BUG(); | |
315 | *p = node->next_hash; | |
316 | node->tree->node_hash_cnt--; | |
317 | } | |
318 | ||
319 | /* Load a particular node out of a tree */ | |
320 | struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num) | |
321 | { | |
322 | struct hfs_bnode *node; | |
323 | struct hfs_bnode_desc *desc; | |
324 | int i, rec_off, off, next_off; | |
325 | int entry_size, key_size; | |
326 | ||
327 | spin_lock(&tree->hash_lock); | |
328 | node = hfs_bnode_findhash(tree, num); | |
329 | if (node) { | |
330 | hfs_bnode_get(node); | |
331 | spin_unlock(&tree->hash_lock); | |
332 | wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags)); | |
333 | if (test_bit(HFS_BNODE_ERROR, &node->flags)) | |
334 | goto node_error; | |
335 | return node; | |
336 | } | |
337 | spin_unlock(&tree->hash_lock); | |
338 | node = __hfs_bnode_create(tree, num); | |
339 | if (!node) | |
340 | return ERR_PTR(-ENOMEM); | |
341 | if (test_bit(HFS_BNODE_ERROR, &node->flags)) | |
342 | goto node_error; | |
343 | if (!test_bit(HFS_BNODE_NEW, &node->flags)) | |
344 | return node; | |
345 | ||
346 | desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset); | |
347 | node->prev = be32_to_cpu(desc->prev); | |
348 | node->next = be32_to_cpu(desc->next); | |
349 | node->num_recs = be16_to_cpu(desc->num_recs); | |
350 | node->type = desc->type; | |
351 | node->height = desc->height; | |
352 | kunmap(node->page[0]); | |
353 | ||
354 | switch (node->type) { | |
355 | case HFS_NODE_HEADER: | |
356 | case HFS_NODE_MAP: | |
357 | if (node->height != 0) | |
358 | goto node_error; | |
359 | break; | |
360 | case HFS_NODE_LEAF: | |
361 | if (node->height != 1) | |
362 | goto node_error; | |
363 | break; | |
364 | case HFS_NODE_INDEX: | |
365 | if (node->height <= 1 || node->height > tree->depth) | |
366 | goto node_error; | |
367 | break; | |
368 | default: | |
369 | goto node_error; | |
370 | } | |
371 | ||
372 | rec_off = tree->node_size - 2; | |
373 | off = hfs_bnode_read_u16(node, rec_off); | |
374 | if (off != sizeof(struct hfs_bnode_desc)) | |
375 | goto node_error; | |
376 | for (i = 1; i <= node->num_recs; off = next_off, i++) { | |
377 | rec_off -= 2; | |
378 | next_off = hfs_bnode_read_u16(node, rec_off); | |
379 | if (next_off <= off || | |
380 | next_off > tree->node_size || | |
381 | next_off & 1) | |
382 | goto node_error; | |
383 | entry_size = next_off - off; | |
384 | if (node->type != HFS_NODE_INDEX && | |
385 | node->type != HFS_NODE_LEAF) | |
386 | continue; | |
387 | key_size = hfs_bnode_read_u8(node, off) + 1; | |
388 | if (key_size >= entry_size /*|| key_size & 1*/) | |
389 | goto node_error; | |
390 | } | |
391 | clear_bit(HFS_BNODE_NEW, &node->flags); | |
392 | wake_up(&node->lock_wq); | |
393 | return node; | |
394 | ||
395 | node_error: | |
396 | set_bit(HFS_BNODE_ERROR, &node->flags); | |
397 | clear_bit(HFS_BNODE_NEW, &node->flags); | |
398 | wake_up(&node->lock_wq); | |
399 | hfs_bnode_put(node); | |
400 | return ERR_PTR(-EIO); | |
401 | } | |
402 | ||
403 | void hfs_bnode_free(struct hfs_bnode *node) | |
404 | { | |
405 | //int i; | |
406 | ||
407 | //for (i = 0; i < node->tree->pages_per_bnode; i++) | |
408 | // if (node->page[i]) | |
409 | // page_cache_release(node->page[i]); | |
410 | kfree(node); | |
411 | } | |
412 | ||
413 | struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num) | |
414 | { | |
415 | struct hfs_bnode *node; | |
416 | struct page **pagep; | |
417 | int i; | |
418 | ||
419 | spin_lock(&tree->hash_lock); | |
420 | node = hfs_bnode_findhash(tree, num); | |
421 | spin_unlock(&tree->hash_lock); | |
422 | if (node) | |
423 | BUG(); | |
424 | node = __hfs_bnode_create(tree, num); | |
425 | if (!node) | |
426 | return ERR_PTR(-ENOMEM); | |
427 | if (test_bit(HFS_BNODE_ERROR, &node->flags)) { | |
428 | hfs_bnode_put(node); | |
429 | return ERR_PTR(-EIO); | |
430 | } | |
431 | ||
432 | pagep = node->page; | |
433 | memset(kmap(*pagep) + node->page_offset, 0, | |
434 | min((int)PAGE_CACHE_SIZE, (int)tree->node_size)); | |
435 | set_page_dirty(*pagep); | |
436 | kunmap(*pagep); | |
437 | for (i = 1; i < tree->pages_per_bnode; i++) { | |
438 | memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE); | |
439 | set_page_dirty(*pagep); | |
440 | kunmap(*pagep); | |
441 | } | |
442 | clear_bit(HFS_BNODE_NEW, &node->flags); | |
443 | wake_up(&node->lock_wq); | |
444 | ||
445 | return node; | |
446 | } | |
447 | ||
448 | void hfs_bnode_get(struct hfs_bnode *node) | |
449 | { | |
450 | if (node) { | |
451 | atomic_inc(&node->refcnt); | |
452 | #if REF_PAGES | |
453 | { | |
454 | int i; | |
455 | for (i = 0; i < node->tree->pages_per_bnode; i++) | |
456 | get_page(node->page[i]); | |
457 | } | |
458 | #endif | |
459 | dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n", | |
460 | node->tree->cnid, node->this, atomic_read(&node->refcnt)); | |
461 | } | |
462 | } | |
463 | ||
464 | /* Dispose of resources used by a node */ | |
465 | void hfs_bnode_put(struct hfs_bnode *node) | |
466 | { | |
467 | if (node) { | |
468 | struct hfs_btree *tree = node->tree; | |
469 | int i; | |
470 | ||
471 | dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n", | |
472 | node->tree->cnid, node->this, atomic_read(&node->refcnt)); | |
473 | if (!atomic_read(&node->refcnt)) | |
474 | BUG(); | |
475 | if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock)) { | |
476 | #if REF_PAGES | |
477 | for (i = 0; i < tree->pages_per_bnode; i++) | |
478 | put_page(node->page[i]); | |
479 | #endif | |
480 | return; | |
481 | } | |
482 | for (i = 0; i < tree->pages_per_bnode; i++) { | |
483 | mark_page_accessed(node->page[i]); | |
484 | #if REF_PAGES | |
485 | put_page(node->page[i]); | |
486 | #endif | |
487 | } | |
488 | ||
489 | if (test_bit(HFS_BNODE_DELETED, &node->flags)) { | |
490 | hfs_bnode_unhash(node); | |
491 | spin_unlock(&tree->hash_lock); | |
492 | hfs_bmap_free(node); | |
493 | hfs_bnode_free(node); | |
494 | return; | |
495 | } | |
496 | spin_unlock(&tree->hash_lock); | |
497 | } | |
498 | } |