bnode.c 12 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * linux/fs/hfs/bnode.c
  4. *
  5. * Copyright (C) 2001
  6. * Brad Boyer (flar@allandria.com)
  7. * (C) 2003 Ardis Technologies <roman@ardistech.com>
  8. *
  9. * Handle basic btree node operations
  10. */
  11. #include <linux/pagemap.h>
  12. #include <linux/slab.h>
  13. #include <linux/swap.h>
  14. #include "btree.h"
  15. void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
  16. {
  17. struct page *page;
  18. int pagenum;
  19. int bytes_read;
  20. int bytes_to_read;
  21. void *vaddr;
  22. off += node->page_offset;
  23. pagenum = off >> PAGE_SHIFT;
  24. off &= ~PAGE_MASK; /* compute page offset for the first page */
  25. for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
  26. if (pagenum >= node->tree->pages_per_bnode)
  27. break;
  28. page = node->page[pagenum];
  29. bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
  30. vaddr = kmap_atomic(page);
  31. memcpy(buf + bytes_read, vaddr + off, bytes_to_read);
  32. kunmap_atomic(vaddr);
  33. pagenum++;
  34. off = 0; /* page offset only applies to the first page */
  35. }
  36. }
  37. u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
  38. {
  39. __be16 data;
  40. // optimize later...
  41. hfs_bnode_read(node, &data, off, 2);
  42. return be16_to_cpu(data);
  43. }
  44. u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
  45. {
  46. u8 data;
  47. // optimize later...
  48. hfs_bnode_read(node, &data, off, 1);
  49. return data;
  50. }
  51. void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
  52. {
  53. struct hfs_btree *tree;
  54. int key_len;
  55. tree = node->tree;
  56. if (node->type == HFS_NODE_LEAF ||
  57. tree->attributes & HFS_TREE_VARIDXKEYS)
  58. key_len = hfs_bnode_read_u8(node, off) + 1;
  59. else
  60. key_len = tree->max_key_len + 1;
  61. hfs_bnode_read(node, key, off, key_len);
  62. }
  63. void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
  64. {
  65. struct page *page;
  66. off += node->page_offset;
  67. page = node->page[0];
  68. memcpy(kmap(page) + off, buf, len);
  69. kunmap(page);
  70. set_page_dirty(page);
  71. }
  72. void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
  73. {
  74. __be16 v = cpu_to_be16(data);
  75. // optimize later...
  76. hfs_bnode_write(node, &v, off, 2);
  77. }
  78. void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
  79. {
  80. // optimize later...
  81. hfs_bnode_write(node, &data, off, 1);
  82. }
  83. void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
  84. {
  85. struct page *page;
  86. off += node->page_offset;
  87. page = node->page[0];
  88. memset(kmap(page) + off, 0, len);
  89. kunmap(page);
  90. set_page_dirty(page);
  91. }
  92. void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
  93. struct hfs_bnode *src_node, int src, int len)
  94. {
  95. struct page *src_page, *dst_page;
  96. hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
  97. if (!len)
  98. return;
  99. src += src_node->page_offset;
  100. dst += dst_node->page_offset;
  101. src_page = src_node->page[0];
  102. dst_page = dst_node->page[0];
  103. memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
  104. kunmap(src_page);
  105. kunmap(dst_page);
  106. set_page_dirty(dst_page);
  107. }
  108. void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
  109. {
  110. struct page *page;
  111. void *ptr;
  112. hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
  113. if (!len)
  114. return;
  115. src += node->page_offset;
  116. dst += node->page_offset;
  117. page = node->page[0];
  118. ptr = kmap(page);
  119. memmove(ptr + dst, ptr + src, len);
  120. kunmap(page);
  121. set_page_dirty(page);
  122. }
  123. void hfs_bnode_dump(struct hfs_bnode *node)
  124. {
  125. struct hfs_bnode_desc desc;
  126. __be32 cnid;
  127. int i, off, key_off;
  128. hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
  129. hfs_bnode_read(node, &desc, 0, sizeof(desc));
  130. hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
  131. be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
  132. desc.type, desc.height, be16_to_cpu(desc.num_recs));
  133. off = node->tree->node_size - 2;
  134. for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
  135. key_off = hfs_bnode_read_u16(node, off);
  136. hfs_dbg_cont(BNODE_MOD, " %d", key_off);
  137. if (i && node->type == HFS_NODE_INDEX) {
  138. int tmp;
  139. if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
  140. tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
  141. else
  142. tmp = node->tree->max_key_len + 1;
  143. hfs_dbg_cont(BNODE_MOD, " (%d,%d",
  144. tmp, hfs_bnode_read_u8(node, key_off));
  145. hfs_bnode_read(node, &cnid, key_off + tmp, 4);
  146. hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
  147. } else if (i && node->type == HFS_NODE_LEAF) {
  148. int tmp;
  149. tmp = hfs_bnode_read_u8(node, key_off);
  150. hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
  151. }
  152. }
  153. hfs_dbg_cont(BNODE_MOD, "\n");
  154. }
  155. void hfs_bnode_unlink(struct hfs_bnode *node)
  156. {
  157. struct hfs_btree *tree;
  158. struct hfs_bnode *tmp;
  159. __be32 cnid;
  160. tree = node->tree;
  161. if (node->prev) {
  162. tmp = hfs_bnode_find(tree, node->prev);
  163. if (IS_ERR(tmp))
  164. return;
  165. tmp->next = node->next;
  166. cnid = cpu_to_be32(tmp->next);
  167. hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
  168. hfs_bnode_put(tmp);
  169. } else if (node->type == HFS_NODE_LEAF)
  170. tree->leaf_head = node->next;
  171. if (node->next) {
  172. tmp = hfs_bnode_find(tree, node->next);
  173. if (IS_ERR(tmp))
  174. return;
  175. tmp->prev = node->prev;
  176. cnid = cpu_to_be32(tmp->prev);
  177. hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
  178. hfs_bnode_put(tmp);
  179. } else if (node->type == HFS_NODE_LEAF)
  180. tree->leaf_tail = node->prev;
  181. // move down?
  182. if (!node->prev && !node->next) {
  183. printk(KERN_DEBUG "hfs_btree_del_level\n");
  184. }
  185. if (!node->parent) {
  186. tree->root = 0;
  187. tree->depth = 0;
  188. }
  189. set_bit(HFS_BNODE_DELETED, &node->flags);
  190. }
  191. static inline int hfs_bnode_hash(u32 num)
  192. {
  193. num = (num >> 16) + num;
  194. num += num >> 8;
  195. return num & (NODE_HASH_SIZE - 1);
  196. }
  197. struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
  198. {
  199. struct hfs_bnode *node;
  200. if (cnid >= tree->node_count) {
  201. pr_err("request for non-existent node %d in B*Tree\n", cnid);
  202. return NULL;
  203. }
  204. for (node = tree->node_hash[hfs_bnode_hash(cnid)];
  205. node; node = node->next_hash) {
  206. if (node->this == cnid) {
  207. return node;
  208. }
  209. }
  210. return NULL;
  211. }
  212. static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
  213. {
  214. struct hfs_bnode *node, *node2;
  215. struct address_space *mapping;
  216. struct page *page;
  217. int size, block, i, hash;
  218. loff_t off;
  219. if (cnid >= tree->node_count) {
  220. pr_err("request for non-existent node %d in B*Tree\n", cnid);
  221. return NULL;
  222. }
  223. size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
  224. sizeof(struct page *);
  225. node = kzalloc(size, GFP_KERNEL);
  226. if (!node)
  227. return NULL;
  228. node->tree = tree;
  229. node->this = cnid;
  230. set_bit(HFS_BNODE_NEW, &node->flags);
  231. atomic_set(&node->refcnt, 1);
  232. hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
  233. node->tree->cnid, node->this);
  234. init_waitqueue_head(&node->lock_wq);
  235. spin_lock(&tree->hash_lock);
  236. node2 = hfs_bnode_findhash(tree, cnid);
  237. if (!node2) {
  238. hash = hfs_bnode_hash(cnid);
  239. node->next_hash = tree->node_hash[hash];
  240. tree->node_hash[hash] = node;
  241. tree->node_hash_cnt++;
  242. } else {
  243. spin_unlock(&tree->hash_lock);
  244. kfree(node);
  245. wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
  246. return node2;
  247. }
  248. spin_unlock(&tree->hash_lock);
  249. mapping = tree->inode->i_mapping;
  250. off = (loff_t)cnid * tree->node_size;
  251. block = off >> PAGE_SHIFT;
  252. node->page_offset = off & ~PAGE_MASK;
  253. for (i = 0; i < tree->pages_per_bnode; i++) {
  254. page = read_mapping_page(mapping, block++, NULL);
  255. if (IS_ERR(page))
  256. goto fail;
  257. if (PageError(page)) {
  258. put_page(page);
  259. goto fail;
  260. }
  261. node->page[i] = page;
  262. }
  263. return node;
  264. fail:
  265. set_bit(HFS_BNODE_ERROR, &node->flags);
  266. return node;
  267. }
  268. void hfs_bnode_unhash(struct hfs_bnode *node)
  269. {
  270. struct hfs_bnode **p;
  271. hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
  272. node->tree->cnid, node->this, atomic_read(&node->refcnt));
  273. for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
  274. *p && *p != node; p = &(*p)->next_hash)
  275. ;
  276. BUG_ON(!*p);
  277. *p = node->next_hash;
  278. node->tree->node_hash_cnt--;
  279. }
  280. /* Load a particular node out of a tree */
  281. struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
  282. {
  283. struct hfs_bnode *node;
  284. struct hfs_bnode_desc *desc;
  285. int i, rec_off, off, next_off;
  286. int entry_size, key_size;
  287. spin_lock(&tree->hash_lock);
  288. node = hfs_bnode_findhash(tree, num);
  289. if (node) {
  290. hfs_bnode_get(node);
  291. spin_unlock(&tree->hash_lock);
  292. wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
  293. if (test_bit(HFS_BNODE_ERROR, &node->flags))
  294. goto node_error;
  295. return node;
  296. }
  297. spin_unlock(&tree->hash_lock);
  298. node = __hfs_bnode_create(tree, num);
  299. if (!node)
  300. return ERR_PTR(-ENOMEM);
  301. if (test_bit(HFS_BNODE_ERROR, &node->flags))
  302. goto node_error;
  303. if (!test_bit(HFS_BNODE_NEW, &node->flags))
  304. return node;
  305. desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
  306. node->prev = be32_to_cpu(desc->prev);
  307. node->next = be32_to_cpu(desc->next);
  308. node->num_recs = be16_to_cpu(desc->num_recs);
  309. node->type = desc->type;
  310. node->height = desc->height;
  311. kunmap(node->page[0]);
  312. switch (node->type) {
  313. case HFS_NODE_HEADER:
  314. case HFS_NODE_MAP:
  315. if (node->height != 0)
  316. goto node_error;
  317. break;
  318. case HFS_NODE_LEAF:
  319. if (node->height != 1)
  320. goto node_error;
  321. break;
  322. case HFS_NODE_INDEX:
  323. if (node->height <= 1 || node->height > tree->depth)
  324. goto node_error;
  325. break;
  326. default:
  327. goto node_error;
  328. }
  329. rec_off = tree->node_size - 2;
  330. off = hfs_bnode_read_u16(node, rec_off);
  331. if (off != sizeof(struct hfs_bnode_desc))
  332. goto node_error;
  333. for (i = 1; i <= node->num_recs; off = next_off, i++) {
  334. rec_off -= 2;
  335. next_off = hfs_bnode_read_u16(node, rec_off);
  336. if (next_off <= off ||
  337. next_off > tree->node_size ||
  338. next_off & 1)
  339. goto node_error;
  340. entry_size = next_off - off;
  341. if (node->type != HFS_NODE_INDEX &&
  342. node->type != HFS_NODE_LEAF)
  343. continue;
  344. key_size = hfs_bnode_read_u8(node, off) + 1;
  345. if (key_size >= entry_size /*|| key_size & 1*/)
  346. goto node_error;
  347. }
  348. clear_bit(HFS_BNODE_NEW, &node->flags);
  349. wake_up(&node->lock_wq);
  350. return node;
  351. node_error:
  352. set_bit(HFS_BNODE_ERROR, &node->flags);
  353. clear_bit(HFS_BNODE_NEW, &node->flags);
  354. wake_up(&node->lock_wq);
  355. hfs_bnode_put(node);
  356. return ERR_PTR(-EIO);
  357. }
  358. void hfs_bnode_free(struct hfs_bnode *node)
  359. {
  360. int i;
  361. for (i = 0; i < node->tree->pages_per_bnode; i++)
  362. if (node->page[i])
  363. put_page(node->page[i]);
  364. kfree(node);
  365. }
  366. struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
  367. {
  368. struct hfs_bnode *node;
  369. struct page **pagep;
  370. int i;
  371. spin_lock(&tree->hash_lock);
  372. node = hfs_bnode_findhash(tree, num);
  373. spin_unlock(&tree->hash_lock);
  374. if (node) {
  375. pr_crit("new node %u already hashed?\n", num);
  376. WARN_ON(1);
  377. return node;
  378. }
  379. node = __hfs_bnode_create(tree, num);
  380. if (!node)
  381. return ERR_PTR(-ENOMEM);
  382. if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
  383. hfs_bnode_put(node);
  384. return ERR_PTR(-EIO);
  385. }
  386. pagep = node->page;
  387. memset(kmap(*pagep) + node->page_offset, 0,
  388. min((int)PAGE_SIZE, (int)tree->node_size));
  389. set_page_dirty(*pagep);
  390. kunmap(*pagep);
  391. for (i = 1; i < tree->pages_per_bnode; i++) {
  392. memset(kmap(*++pagep), 0, PAGE_SIZE);
  393. set_page_dirty(*pagep);
  394. kunmap(*pagep);
  395. }
  396. clear_bit(HFS_BNODE_NEW, &node->flags);
  397. wake_up(&node->lock_wq);
  398. return node;
  399. }
  400. void hfs_bnode_get(struct hfs_bnode *node)
  401. {
  402. if (node) {
  403. atomic_inc(&node->refcnt);
  404. hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
  405. node->tree->cnid, node->this,
  406. atomic_read(&node->refcnt));
  407. }
  408. }
  409. /* Dispose of resources used by a node */
  410. void hfs_bnode_put(struct hfs_bnode *node)
  411. {
  412. if (node) {
  413. struct hfs_btree *tree = node->tree;
  414. int i;
  415. hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
  416. node->tree->cnid, node->this,
  417. atomic_read(&node->refcnt));
  418. BUG_ON(!atomic_read(&node->refcnt));
  419. if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
  420. return;
  421. for (i = 0; i < tree->pages_per_bnode; i++) {
  422. if (!node->page[i])
  423. continue;
  424. mark_page_accessed(node->page[i]);
  425. }
  426. if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
  427. hfs_bnode_unhash(node);
  428. spin_unlock(&tree->hash_lock);
  429. hfs_bmap_free(node);
  430. hfs_bnode_free(node);
  431. return;
  432. }
  433. spin_unlock(&tree->hash_lock);
  434. }
  435. }