bnode.c 11 KB

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