brec.c 14 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * linux/fs/hfsplus/brec.c
  4. *
  5. * Copyright (C) 2001
  6. * Brad Boyer (flar@allandria.com)
  7. * (C) 2003 Ardis Technologies <roman@ardistech.com>
  8. *
  9. * Handle individual btree records
  10. */
  11. #include "hfsplus_fs.h"
  12. #include "hfsplus_raw.h"
  13. static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  14. static int hfs_brec_update_parent(struct hfs_find_data *fd);
  15. static int hfs_btree_inc_height(struct hfs_btree *);
  16. /* Get the length and offset of the given record in the given node */
  17. u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
  18. {
  19. __be16 retval[2];
  20. u16 dataoff;
  21. dataoff = node->tree->node_size - (rec + 2) * 2;
  22. hfs_bnode_read(node, retval, dataoff, 4);
  23. *off = be16_to_cpu(retval[1]);
  24. return be16_to_cpu(retval[0]) - *off;
  25. }
  26. /* Get the length of the key from a keyed record */
  27. u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
  28. {
  29. u16 retval, recoff;
  30. if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
  31. return 0;
  32. if ((node->type == HFS_NODE_INDEX) &&
  33. !(node->tree->attributes & HFS_TREE_VARIDXKEYS) &&
  34. (node->tree->cnid != HFSPLUS_ATTR_CNID)) {
  35. retval = node->tree->max_key_len + 2;
  36. } else {
  37. recoff = hfs_bnode_read_u16(node,
  38. node->tree->node_size - (rec + 1) * 2);
  39. if (!recoff)
  40. return 0;
  41. if (recoff > node->tree->node_size - 2) {
  42. pr_err("recoff %d too large\n", recoff);
  43. return 0;
  44. }
  45. retval = hfs_bnode_read_u16(node, recoff) + 2;
  46. if (retval > node->tree->max_key_len + 2) {
  47. pr_err("keylen %d too large\n",
  48. retval);
  49. retval = 0;
  50. }
  51. }
  52. return retval;
  53. }
  54. int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  55. {
  56. struct hfs_btree *tree;
  57. struct hfs_bnode *node, *new_node;
  58. int size, key_len, rec;
  59. int data_off, end_off;
  60. int idx_rec_off, data_rec_off, end_rec_off;
  61. __be32 cnid;
  62. tree = fd->tree;
  63. if (!fd->bnode) {
  64. if (!tree->root)
  65. hfs_btree_inc_height(tree);
  66. node = hfs_bnode_find(tree, tree->leaf_head);
  67. if (IS_ERR(node))
  68. return PTR_ERR(node);
  69. fd->bnode = node;
  70. fd->record = -1;
  71. }
  72. new_node = NULL;
  73. key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  74. again:
  75. /* new record idx and complete record size */
  76. rec = fd->record + 1;
  77. size = key_len + entry_len;
  78. node = fd->bnode;
  79. hfs_bnode_dump(node);
  80. /* get last offset */
  81. end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  82. end_off = hfs_bnode_read_u16(node, end_rec_off);
  83. end_rec_off -= 2;
  84. hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
  85. rec, size, end_off, end_rec_off);
  86. if (size > end_rec_off - end_off) {
  87. if (new_node)
  88. panic("not enough room!\n");
  89. new_node = hfs_bnode_split(fd);
  90. if (IS_ERR(new_node))
  91. return PTR_ERR(new_node);
  92. goto again;
  93. }
  94. if (node->type == HFS_NODE_LEAF) {
  95. tree->leaf_count++;
  96. mark_inode_dirty(tree->inode);
  97. }
  98. node->num_recs++;
  99. /* write new last offset */
  100. hfs_bnode_write_u16(node,
  101. offsetof(struct hfs_bnode_desc, num_recs),
  102. node->num_recs);
  103. hfs_bnode_write_u16(node, end_rec_off, end_off + size);
  104. data_off = end_off;
  105. data_rec_off = end_rec_off + 2;
  106. idx_rec_off = tree->node_size - (rec + 1) * 2;
  107. if (idx_rec_off == data_rec_off)
  108. goto skip;
  109. /* move all following entries */
  110. do {
  111. data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
  112. hfs_bnode_write_u16(node, data_rec_off, data_off + size);
  113. data_rec_off += 2;
  114. } while (data_rec_off < idx_rec_off);
  115. /* move data away */
  116. hfs_bnode_move(node, data_off + size, data_off,
  117. end_off - data_off);
  118. skip:
  119. hfs_bnode_write(node, fd->search_key, data_off, key_len);
  120. hfs_bnode_write(node, entry, data_off + key_len, entry_len);
  121. hfs_bnode_dump(node);
  122. /*
  123. * update parent key if we inserted a key
  124. * at the start of the node and it is not the new node
  125. */
  126. if (!rec && new_node != node) {
  127. hfs_bnode_read_key(node, fd->search_key, data_off + size);
  128. hfs_brec_update_parent(fd);
  129. }
  130. if (new_node) {
  131. hfs_bnode_put(fd->bnode);
  132. if (!new_node->parent) {
  133. hfs_btree_inc_height(tree);
  134. new_node->parent = tree->root;
  135. }
  136. fd->bnode = hfs_bnode_find(tree, new_node->parent);
  137. /* create index data entry */
  138. cnid = cpu_to_be32(new_node->this);
  139. entry = &cnid;
  140. entry_len = sizeof(cnid);
  141. /* get index key */
  142. hfs_bnode_read_key(new_node, fd->search_key, 14);
  143. __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
  144. hfs_bnode_put(new_node);
  145. new_node = NULL;
  146. if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
  147. (tree->cnid == HFSPLUS_ATTR_CNID))
  148. key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  149. else {
  150. fd->search_key->key_len =
  151. cpu_to_be16(tree->max_key_len);
  152. key_len = tree->max_key_len + 2;
  153. }
  154. goto again;
  155. }
  156. return 0;
  157. }
  158. int hfs_brec_remove(struct hfs_find_data *fd)
  159. {
  160. struct hfs_btree *tree;
  161. struct hfs_bnode *node, *parent;
  162. int end_off, rec_off, data_off, size;
  163. tree = fd->tree;
  164. node = fd->bnode;
  165. again:
  166. rec_off = tree->node_size - (fd->record + 2) * 2;
  167. end_off = tree->node_size - (node->num_recs + 1) * 2;
  168. if (node->type == HFS_NODE_LEAF) {
  169. tree->leaf_count--;
  170. mark_inode_dirty(tree->inode);
  171. }
  172. hfs_bnode_dump(node);
  173. hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
  174. fd->record, fd->keylength + fd->entrylength);
  175. if (!--node->num_recs) {
  176. hfs_bnode_unlink(node);
  177. if (!node->parent)
  178. return 0;
  179. parent = hfs_bnode_find(tree, node->parent);
  180. if (IS_ERR(parent))
  181. return PTR_ERR(parent);
  182. hfs_bnode_put(node);
  183. node = fd->bnode = parent;
  184. __hfs_brec_find(node, fd, hfs_find_rec_by_key);
  185. goto again;
  186. }
  187. hfs_bnode_write_u16(node,
  188. offsetof(struct hfs_bnode_desc, num_recs),
  189. node->num_recs);
  190. if (rec_off == end_off)
  191. goto skip;
  192. size = fd->keylength + fd->entrylength;
  193. do {
  194. data_off = hfs_bnode_read_u16(node, rec_off);
  195. hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
  196. rec_off -= 2;
  197. } while (rec_off >= end_off);
  198. /* fill hole */
  199. hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
  200. data_off - fd->keyoffset - size);
  201. skip:
  202. hfs_bnode_dump(node);
  203. if (!fd->record)
  204. hfs_brec_update_parent(fd);
  205. return 0;
  206. }
  207. static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
  208. {
  209. struct hfs_btree *tree;
  210. struct hfs_bnode *node, *new_node, *next_node;
  211. struct hfs_bnode_desc node_desc;
  212. int num_recs, new_rec_off, new_off, old_rec_off;
  213. int data_start, data_end, size;
  214. tree = fd->tree;
  215. node = fd->bnode;
  216. new_node = hfs_bmap_alloc(tree);
  217. if (IS_ERR(new_node))
  218. return new_node;
  219. hfs_bnode_get(node);
  220. hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
  221. node->this, new_node->this, node->next);
  222. new_node->next = node->next;
  223. new_node->prev = node->this;
  224. new_node->parent = node->parent;
  225. new_node->type = node->type;
  226. new_node->height = node->height;
  227. if (node->next)
  228. next_node = hfs_bnode_find(tree, node->next);
  229. else
  230. next_node = NULL;
  231. if (IS_ERR(next_node)) {
  232. hfs_bnode_put(node);
  233. hfs_bnode_put(new_node);
  234. return next_node;
  235. }
  236. size = tree->node_size / 2 - node->num_recs * 2 - 14;
  237. old_rec_off = tree->node_size - 4;
  238. num_recs = 1;
  239. for (;;) {
  240. data_start = hfs_bnode_read_u16(node, old_rec_off);
  241. if (data_start > size)
  242. break;
  243. old_rec_off -= 2;
  244. if (++num_recs < node->num_recs)
  245. continue;
  246. /* panic? */
  247. hfs_bnode_put(node);
  248. hfs_bnode_put(new_node);
  249. if (next_node)
  250. hfs_bnode_put(next_node);
  251. return ERR_PTR(-ENOSPC);
  252. }
  253. if (fd->record + 1 < num_recs) {
  254. /* new record is in the lower half,
  255. * so leave some more space there
  256. */
  257. old_rec_off += 2;
  258. num_recs--;
  259. data_start = hfs_bnode_read_u16(node, old_rec_off);
  260. } else {
  261. hfs_bnode_put(node);
  262. hfs_bnode_get(new_node);
  263. fd->bnode = new_node;
  264. fd->record -= num_recs;
  265. fd->keyoffset -= data_start - 14;
  266. fd->entryoffset -= data_start - 14;
  267. }
  268. new_node->num_recs = node->num_recs - num_recs;
  269. node->num_recs = num_recs;
  270. new_rec_off = tree->node_size - 2;
  271. new_off = 14;
  272. size = data_start - new_off;
  273. num_recs = new_node->num_recs;
  274. data_end = data_start;
  275. while (num_recs) {
  276. hfs_bnode_write_u16(new_node, new_rec_off, new_off);
  277. old_rec_off -= 2;
  278. new_rec_off -= 2;
  279. data_end = hfs_bnode_read_u16(node, old_rec_off);
  280. new_off = data_end - size;
  281. num_recs--;
  282. }
  283. hfs_bnode_write_u16(new_node, new_rec_off, new_off);
  284. hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
  285. /* update new bnode header */
  286. node_desc.next = cpu_to_be32(new_node->next);
  287. node_desc.prev = cpu_to_be32(new_node->prev);
  288. node_desc.type = new_node->type;
  289. node_desc.height = new_node->height;
  290. node_desc.num_recs = cpu_to_be16(new_node->num_recs);
  291. node_desc.reserved = 0;
  292. hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
  293. /* update previous bnode header */
  294. node->next = new_node->this;
  295. hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
  296. node_desc.next = cpu_to_be32(node->next);
  297. node_desc.num_recs = cpu_to_be16(node->num_recs);
  298. hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
  299. /* update next bnode header */
  300. if (next_node) {
  301. next_node->prev = new_node->this;
  302. hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
  303. node_desc.prev = cpu_to_be32(next_node->prev);
  304. hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
  305. hfs_bnode_put(next_node);
  306. } else if (node->this == tree->leaf_tail) {
  307. /* if there is no next node, this might be the new tail */
  308. tree->leaf_tail = new_node->this;
  309. mark_inode_dirty(tree->inode);
  310. }
  311. hfs_bnode_dump(node);
  312. hfs_bnode_dump(new_node);
  313. hfs_bnode_put(node);
  314. return new_node;
  315. }
  316. static int hfs_brec_update_parent(struct hfs_find_data *fd)
  317. {
  318. struct hfs_btree *tree;
  319. struct hfs_bnode *node, *new_node, *parent;
  320. int newkeylen, diff;
  321. int rec, rec_off, end_rec_off;
  322. int start_off, end_off;
  323. tree = fd->tree;
  324. node = fd->bnode;
  325. new_node = NULL;
  326. if (!node->parent)
  327. return 0;
  328. again:
  329. parent = hfs_bnode_find(tree, node->parent);
  330. if (IS_ERR(parent))
  331. return PTR_ERR(parent);
  332. __hfs_brec_find(parent, fd, hfs_find_rec_by_key);
  333. if (fd->record < 0)
  334. return -ENOENT;
  335. hfs_bnode_dump(parent);
  336. rec = fd->record;
  337. /* size difference between old and new key */
  338. if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
  339. (tree->cnid == HFSPLUS_ATTR_CNID))
  340. newkeylen = hfs_bnode_read_u16(node, 14) + 2;
  341. else
  342. fd->keylength = newkeylen = tree->max_key_len + 2;
  343. hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
  344. rec, fd->keylength, newkeylen);
  345. rec_off = tree->node_size - (rec + 2) * 2;
  346. end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
  347. diff = newkeylen - fd->keylength;
  348. if (!diff)
  349. goto skip;
  350. if (diff > 0) {
  351. end_off = hfs_bnode_read_u16(parent, end_rec_off);
  352. if (end_rec_off - end_off < diff) {
  353. hfs_dbg(BNODE_MOD, "splitting index node\n");
  354. fd->bnode = parent;
  355. new_node = hfs_bnode_split(fd);
  356. if (IS_ERR(new_node))
  357. return PTR_ERR(new_node);
  358. parent = fd->bnode;
  359. rec = fd->record;
  360. rec_off = tree->node_size - (rec + 2) * 2;
  361. end_rec_off = tree->node_size -
  362. (parent->num_recs + 1) * 2;
  363. }
  364. }
  365. end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
  366. hfs_bnode_write_u16(parent, rec_off, start_off + diff);
  367. start_off -= 4; /* move previous cnid too */
  368. while (rec_off > end_rec_off) {
  369. rec_off -= 2;
  370. end_off = hfs_bnode_read_u16(parent, rec_off);
  371. hfs_bnode_write_u16(parent, rec_off, end_off + diff);
  372. }
  373. hfs_bnode_move(parent, start_off + diff, start_off,
  374. end_off - start_off);
  375. skip:
  376. hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
  377. hfs_bnode_dump(parent);
  378. hfs_bnode_put(node);
  379. node = parent;
  380. if (new_node) {
  381. __be32 cnid;
  382. if (!new_node->parent) {
  383. hfs_btree_inc_height(tree);
  384. new_node->parent = tree->root;
  385. }
  386. fd->bnode = hfs_bnode_find(tree, new_node->parent);
  387. /* create index key and entry */
  388. hfs_bnode_read_key(new_node, fd->search_key, 14);
  389. cnid = cpu_to_be32(new_node->this);
  390. __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
  391. hfs_brec_insert(fd, &cnid, sizeof(cnid));
  392. hfs_bnode_put(fd->bnode);
  393. hfs_bnode_put(new_node);
  394. if (!rec) {
  395. if (new_node == node)
  396. goto out;
  397. /* restore search_key */
  398. hfs_bnode_read_key(node, fd->search_key, 14);
  399. }
  400. new_node = NULL;
  401. }
  402. if (!rec && node->parent)
  403. goto again;
  404. out:
  405. fd->bnode = node;
  406. return 0;
  407. }
  408. static int hfs_btree_inc_height(struct hfs_btree *tree)
  409. {
  410. struct hfs_bnode *node, *new_node;
  411. struct hfs_bnode_desc node_desc;
  412. int key_size, rec;
  413. __be32 cnid;
  414. node = NULL;
  415. if (tree->root) {
  416. node = hfs_bnode_find(tree, tree->root);
  417. if (IS_ERR(node))
  418. return PTR_ERR(node);
  419. }
  420. new_node = hfs_bmap_alloc(tree);
  421. if (IS_ERR(new_node)) {
  422. hfs_bnode_put(node);
  423. return PTR_ERR(new_node);
  424. }
  425. tree->root = new_node->this;
  426. if (!tree->depth) {
  427. tree->leaf_head = tree->leaf_tail = new_node->this;
  428. new_node->type = HFS_NODE_LEAF;
  429. new_node->num_recs = 0;
  430. } else {
  431. new_node->type = HFS_NODE_INDEX;
  432. new_node->num_recs = 1;
  433. }
  434. new_node->parent = 0;
  435. new_node->next = 0;
  436. new_node->prev = 0;
  437. new_node->height = ++tree->depth;
  438. node_desc.next = cpu_to_be32(new_node->next);
  439. node_desc.prev = cpu_to_be32(new_node->prev);
  440. node_desc.type = new_node->type;
  441. node_desc.height = new_node->height;
  442. node_desc.num_recs = cpu_to_be16(new_node->num_recs);
  443. node_desc.reserved = 0;
  444. hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
  445. rec = tree->node_size - 2;
  446. hfs_bnode_write_u16(new_node, rec, 14);
  447. if (node) {
  448. /* insert old root idx into new root */
  449. node->parent = tree->root;
  450. if (node->type == HFS_NODE_LEAF ||
  451. tree->attributes & HFS_TREE_VARIDXKEYS ||
  452. tree->cnid == HFSPLUS_ATTR_CNID)
  453. key_size = hfs_bnode_read_u16(node, 14) + 2;
  454. else
  455. key_size = tree->max_key_len + 2;
  456. hfs_bnode_copy(new_node, 14, node, 14, key_size);
  457. if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
  458. (tree->cnid != HFSPLUS_ATTR_CNID)) {
  459. key_size = tree->max_key_len + 2;
  460. hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
  461. }
  462. cnid = cpu_to_be32(node->this);
  463. hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
  464. rec -= 2;
  465. hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
  466. hfs_bnode_put(node);
  467. }
  468. hfs_bnode_put(new_node);
  469. mark_inode_dirty(tree->inode);
  470. return 0;
  471. }