brec.c 13 KB

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  1. /*
  2. * linux/fs/hfs/brec.c
  3. *
  4. * Copyright (C) 2001
  5. * Brad Boyer (flar@allandria.com)
  6. * (C) 2003 Ardis Technologies <roman@ardistech.com>
  7. *
  8. * Handle individual btree records
  9. */
  10. #include "btree.h"
  11. static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  12. static int hfs_brec_update_parent(struct hfs_find_data *fd);
  13. static int hfs_btree_inc_height(struct hfs_btree *tree);
  14. /* Get the length and offset of the given record in the given node */
  15. u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
  16. {
  17. __be16 retval[2];
  18. u16 dataoff;
  19. dataoff = node->tree->node_size - (rec + 2) * 2;
  20. hfs_bnode_read(node, retval, dataoff, 4);
  21. *off = be16_to_cpu(retval[1]);
  22. return be16_to_cpu(retval[0]) - *off;
  23. }
  24. /* Get the length of the key from a keyed record */
  25. u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
  26. {
  27. u16 retval, recoff;
  28. if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
  29. return 0;
  30. if ((node->type == HFS_NODE_INDEX) &&
  31. !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
  32. if (node->tree->attributes & HFS_TREE_BIGKEYS)
  33. retval = node->tree->max_key_len + 2;
  34. else
  35. retval = node->tree->max_key_len + 1;
  36. } else {
  37. recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
  38. if (!recoff)
  39. return 0;
  40. if (node->tree->attributes & HFS_TREE_BIGKEYS)
  41. retval = hfs_bnode_read_u16(node, recoff) + 2;
  42. else
  43. retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  44. }
  45. return retval;
  46. }
  47. int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  48. {
  49. struct hfs_btree *tree;
  50. struct hfs_bnode *node, *new_node;
  51. int size, key_len, rec;
  52. int data_off, end_off;
  53. int idx_rec_off, data_rec_off, end_rec_off;
  54. __be32 cnid;
  55. tree = fd->tree;
  56. if (!fd->bnode) {
  57. if (!tree->root)
  58. hfs_btree_inc_height(tree);
  59. fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  60. if (IS_ERR(fd->bnode))
  61. return PTR_ERR(fd->bnode);
  62. fd->record = -1;
  63. }
  64. new_node = NULL;
  65. key_len = (fd->search_key->key_len | 1) + 1;
  66. again:
  67. /* new record idx and complete record size */
  68. rec = fd->record + 1;
  69. size = key_len + entry_len;
  70. node = fd->bnode;
  71. hfs_bnode_dump(node);
  72. /* get last offset */
  73. end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  74. end_off = hfs_bnode_read_u16(node, end_rec_off);
  75. end_rec_off -= 2;
  76. dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  77. if (size > end_rec_off - end_off) {
  78. if (new_node)
  79. panic("not enough room!\n");
  80. new_node = hfs_bnode_split(fd);
  81. if (IS_ERR(new_node))
  82. return PTR_ERR(new_node);
  83. goto again;
  84. }
  85. if (node->type == HFS_NODE_LEAF) {
  86. tree->leaf_count++;
  87. mark_inode_dirty(tree->inode);
  88. }
  89. node->num_recs++;
  90. /* write new last offset */
  91. hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
  92. hfs_bnode_write_u16(node, end_rec_off, end_off + size);
  93. data_off = end_off;
  94. data_rec_off = end_rec_off + 2;
  95. idx_rec_off = tree->node_size - (rec + 1) * 2;
  96. if (idx_rec_off == data_rec_off)
  97. goto skip;
  98. /* move all following entries */
  99. do {
  100. data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
  101. hfs_bnode_write_u16(node, data_rec_off, data_off + size);
  102. data_rec_off += 2;
  103. } while (data_rec_off < idx_rec_off);
  104. /* move data away */
  105. hfs_bnode_move(node, data_off + size, data_off,
  106. end_off - data_off);
  107. skip:
  108. hfs_bnode_write(node, fd->search_key, data_off, key_len);
  109. hfs_bnode_write(node, entry, data_off + key_len, entry_len);
  110. hfs_bnode_dump(node);
  111. if (new_node) {
  112. /* update parent key if we inserted a key
  113. * at the start of the first node
  114. */
  115. if (!rec && new_node != node)
  116. hfs_brec_update_parent(fd);
  117. hfs_bnode_put(fd->bnode);
  118. if (!new_node->parent) {
  119. hfs_btree_inc_height(tree);
  120. new_node->parent = tree->root;
  121. }
  122. fd->bnode = hfs_bnode_find(tree, new_node->parent);
  123. /* create index data entry */
  124. cnid = cpu_to_be32(new_node->this);
  125. entry = &cnid;
  126. entry_len = sizeof(cnid);
  127. /* get index key */
  128. hfs_bnode_read_key(new_node, fd->search_key, 14);
  129. __hfs_brec_find(fd->bnode, fd);
  130. hfs_bnode_put(new_node);
  131. new_node = NULL;
  132. if (tree->attributes & HFS_TREE_VARIDXKEYS)
  133. key_len = fd->search_key->key_len + 1;
  134. else {
  135. fd->search_key->key_len = tree->max_key_len;
  136. key_len = tree->max_key_len + 1;
  137. }
  138. goto again;
  139. }
  140. if (!rec)
  141. hfs_brec_update_parent(fd);
  142. return 0;
  143. }
  144. int hfs_brec_remove(struct hfs_find_data *fd)
  145. {
  146. struct hfs_btree *tree;
  147. struct hfs_bnode *node, *parent;
  148. int end_off, rec_off, data_off, size;
  149. tree = fd->tree;
  150. node = fd->bnode;
  151. again:
  152. rec_off = tree->node_size - (fd->record + 2) * 2;
  153. end_off = tree->node_size - (node->num_recs + 1) * 2;
  154. if (node->type == HFS_NODE_LEAF) {
  155. tree->leaf_count--;
  156. mark_inode_dirty(tree->inode);
  157. }
  158. hfs_bnode_dump(node);
  159. dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
  160. if (!--node->num_recs) {
  161. hfs_bnode_unlink(node);
  162. if (!node->parent)
  163. return 0;
  164. parent = hfs_bnode_find(tree, node->parent);
  165. if (IS_ERR(parent))
  166. return PTR_ERR(parent);
  167. hfs_bnode_put(node);
  168. node = fd->bnode = parent;
  169. __hfs_brec_find(node, fd);
  170. goto again;
  171. }
  172. hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
  173. if (rec_off == end_off)
  174. goto skip;
  175. size = fd->keylength + fd->entrylength;
  176. do {
  177. data_off = hfs_bnode_read_u16(node, rec_off);
  178. hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
  179. rec_off -= 2;
  180. } while (rec_off >= end_off);
  181. /* fill hole */
  182. hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
  183. data_off - fd->keyoffset - size);
  184. skip:
  185. hfs_bnode_dump(node);
  186. if (!fd->record)
  187. hfs_brec_update_parent(fd);
  188. return 0;
  189. }
  190. static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
  191. {
  192. struct hfs_btree *tree;
  193. struct hfs_bnode *node, *new_node;
  194. struct hfs_bnode_desc node_desc;
  195. int num_recs, new_rec_off, new_off, old_rec_off;
  196. int data_start, data_end, size;
  197. tree = fd->tree;
  198. node = fd->bnode;
  199. new_node = hfs_bmap_alloc(tree);
  200. if (IS_ERR(new_node))
  201. return new_node;
  202. hfs_bnode_get(node);
  203. dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
  204. node->this, new_node->this, node->next);
  205. new_node->next = node->next;
  206. new_node->prev = node->this;
  207. new_node->parent = node->parent;
  208. new_node->type = node->type;
  209. new_node->height = node->height;
  210. size = tree->node_size / 2 - node->num_recs * 2 - 14;
  211. old_rec_off = tree->node_size - 4;
  212. num_recs = 1;
  213. for (;;) {
  214. data_start = hfs_bnode_read_u16(node, old_rec_off);
  215. if (data_start > size)
  216. break;
  217. old_rec_off -= 2;
  218. if (++num_recs < node->num_recs)
  219. continue;
  220. /* panic? */
  221. hfs_bnode_put(node);
  222. hfs_bnode_put(new_node);
  223. return ERR_PTR(-ENOSPC);
  224. }
  225. if (fd->record + 1 < num_recs) {
  226. /* new record is in the lower half,
  227. * so leave some more space there
  228. */
  229. old_rec_off += 2;
  230. num_recs--;
  231. data_start = hfs_bnode_read_u16(node, old_rec_off);
  232. } else {
  233. hfs_bnode_put(node);
  234. hfs_bnode_get(new_node);
  235. fd->bnode = new_node;
  236. fd->record -= num_recs;
  237. fd->keyoffset -= data_start - 14;
  238. fd->entryoffset -= data_start - 14;
  239. }
  240. new_node->num_recs = node->num_recs - num_recs;
  241. node->num_recs = num_recs;
  242. new_rec_off = tree->node_size - 2;
  243. new_off = 14;
  244. size = data_start - new_off;
  245. num_recs = new_node->num_recs;
  246. data_end = data_start;
  247. while (num_recs) {
  248. hfs_bnode_write_u16(new_node, new_rec_off, new_off);
  249. old_rec_off -= 2;
  250. new_rec_off -= 2;
  251. data_end = hfs_bnode_read_u16(node, old_rec_off);
  252. new_off = data_end - size;
  253. num_recs--;
  254. }
  255. hfs_bnode_write_u16(new_node, new_rec_off, new_off);
  256. hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
  257. /* update new bnode header */
  258. node_desc.next = cpu_to_be32(new_node->next);
  259. node_desc.prev = cpu_to_be32(new_node->prev);
  260. node_desc.type = new_node->type;
  261. node_desc.height = new_node->height;
  262. node_desc.num_recs = cpu_to_be16(new_node->num_recs);
  263. node_desc.reserved = 0;
  264. hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
  265. /* update previous bnode header */
  266. node->next = new_node->this;
  267. hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
  268. node_desc.next = cpu_to_be32(node->next);
  269. node_desc.num_recs = cpu_to_be16(node->num_recs);
  270. hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
  271. /* update next bnode header */
  272. if (new_node->next) {
  273. struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
  274. next_node->prev = new_node->this;
  275. hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
  276. node_desc.prev = cpu_to_be32(next_node->prev);
  277. hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
  278. hfs_bnode_put(next_node);
  279. } else if (node->this == tree->leaf_tail) {
  280. /* if there is no next node, this might be the new tail */
  281. tree->leaf_tail = new_node->this;
  282. mark_inode_dirty(tree->inode);
  283. }
  284. hfs_bnode_dump(node);
  285. hfs_bnode_dump(new_node);
  286. hfs_bnode_put(node);
  287. return new_node;
  288. }
  289. static int hfs_brec_update_parent(struct hfs_find_data *fd)
  290. {
  291. struct hfs_btree *tree;
  292. struct hfs_bnode *node, *new_node, *parent;
  293. int newkeylen, diff;
  294. int rec, rec_off, end_rec_off;
  295. int start_off, end_off;
  296. tree = fd->tree;
  297. node = fd->bnode;
  298. new_node = NULL;
  299. if (!node->parent)
  300. return 0;
  301. again:
  302. parent = hfs_bnode_find(tree, node->parent);
  303. if (IS_ERR(parent))
  304. return PTR_ERR(parent);
  305. __hfs_brec_find(parent, fd);
  306. hfs_bnode_dump(parent);
  307. rec = fd->record;
  308. /* size difference between old and new key */
  309. if (tree->attributes & HFS_TREE_VARIDXKEYS)
  310. newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
  311. else
  312. fd->keylength = newkeylen = tree->max_key_len + 1;
  313. dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
  314. rec_off = tree->node_size - (rec + 2) * 2;
  315. end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
  316. diff = newkeylen - fd->keylength;
  317. if (!diff)
  318. goto skip;
  319. if (diff > 0) {
  320. end_off = hfs_bnode_read_u16(parent, end_rec_off);
  321. if (end_rec_off - end_off < diff) {
  322. printk(KERN_DEBUG "hfs: splitting index node...\n");
  323. fd->bnode = parent;
  324. new_node = hfs_bnode_split(fd);
  325. if (IS_ERR(new_node))
  326. return PTR_ERR(new_node);
  327. parent = fd->bnode;
  328. rec = fd->record;
  329. rec_off = tree->node_size - (rec + 2) * 2;
  330. end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
  331. }
  332. }
  333. end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
  334. hfs_bnode_write_u16(parent, rec_off, start_off + diff);
  335. start_off -= 4; /* move previous cnid too */
  336. while (rec_off > end_rec_off) {
  337. rec_off -= 2;
  338. end_off = hfs_bnode_read_u16(parent, rec_off);
  339. hfs_bnode_write_u16(parent, rec_off, end_off + diff);
  340. }
  341. hfs_bnode_move(parent, start_off + diff, start_off,
  342. end_off - start_off);
  343. skip:
  344. hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
  345. if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
  346. hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
  347. hfs_bnode_dump(parent);
  348. hfs_bnode_put(node);
  349. node = parent;
  350. if (new_node) {
  351. __be32 cnid;
  352. fd->bnode = hfs_bnode_find(tree, new_node->parent);
  353. /* create index key and entry */
  354. hfs_bnode_read_key(new_node, fd->search_key, 14);
  355. cnid = cpu_to_be32(new_node->this);
  356. __hfs_brec_find(fd->bnode, fd);
  357. hfs_brec_insert(fd, &cnid, sizeof(cnid));
  358. hfs_bnode_put(fd->bnode);
  359. hfs_bnode_put(new_node);
  360. if (!rec) {
  361. if (new_node == node)
  362. goto out;
  363. /* restore search_key */
  364. hfs_bnode_read_key(node, fd->search_key, 14);
  365. }
  366. }
  367. if (!rec && node->parent)
  368. goto again;
  369. out:
  370. fd->bnode = node;
  371. return 0;
  372. }
  373. static int hfs_btree_inc_height(struct hfs_btree *tree)
  374. {
  375. struct hfs_bnode *node, *new_node;
  376. struct hfs_bnode_desc node_desc;
  377. int key_size, rec;
  378. __be32 cnid;
  379. node = NULL;
  380. if (tree->root) {
  381. node = hfs_bnode_find(tree, tree->root);
  382. if (IS_ERR(node))
  383. return PTR_ERR(node);
  384. }
  385. new_node = hfs_bmap_alloc(tree);
  386. if (IS_ERR(new_node)) {
  387. hfs_bnode_put(node);
  388. return PTR_ERR(new_node);
  389. }
  390. tree->root = new_node->this;
  391. if (!tree->depth) {
  392. tree->leaf_head = tree->leaf_tail = new_node->this;
  393. new_node->type = HFS_NODE_LEAF;
  394. new_node->num_recs = 0;
  395. } else {
  396. new_node->type = HFS_NODE_INDEX;
  397. new_node->num_recs = 1;
  398. }
  399. new_node->parent = 0;
  400. new_node->next = 0;
  401. new_node->prev = 0;
  402. new_node->height = ++tree->depth;
  403. node_desc.next = cpu_to_be32(new_node->next);
  404. node_desc.prev = cpu_to_be32(new_node->prev);
  405. node_desc.type = new_node->type;
  406. node_desc.height = new_node->height;
  407. node_desc.num_recs = cpu_to_be16(new_node->num_recs);
  408. node_desc.reserved = 0;
  409. hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
  410. rec = tree->node_size - 2;
  411. hfs_bnode_write_u16(new_node, rec, 14);
  412. if (node) {
  413. /* insert old root idx into new root */
  414. node->parent = tree->root;
  415. if (node->type == HFS_NODE_LEAF ||
  416. tree->attributes & HFS_TREE_VARIDXKEYS)
  417. key_size = hfs_bnode_read_u8(node, 14) + 1;
  418. else
  419. key_size = tree->max_key_len + 1;
  420. hfs_bnode_copy(new_node, 14, node, 14, key_size);
  421. if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
  422. key_size = tree->max_key_len + 1;
  423. hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
  424. }
  425. key_size = (key_size + 1) & -2;
  426. cnid = cpu_to_be32(node->this);
  427. hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
  428. rec -= 2;
  429. hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
  430. hfs_bnode_put(node);
  431. }
  432. hfs_bnode_put(new_node);
  433. mark_inode_dirty(tree->inode);
  434. return 0;
  435. }