1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/hfs/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
12 #include "btree.h"
13
14 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
15 static int hfs_brec_update_parent(struct hfs_find_data *fd);
16 static int hfs_btree_inc_height(struct hfs_btree *tree);
17
18 /* Get the length and offset of the given record in the given node */
19 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
20 {
21 __be16 retval[2];
22 u16 dataoff;
23
24 dataoff = node->tree->node_size - (rec + 2) * 2;
25 hfs_bnode_read(node, retval, dataoff, 4);
26 *off = be16_to_cpu(retval[1]);
27 return be16_to_cpu(retval[0]) - *off;
28 }
29
30 /* Get the length of the key from a keyed record */
31 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
32 {
33 u16 retval, recoff;
34
35 if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
36 return 0;
37
38 if ((node->type == HFS_NODE_INDEX) &&
39 !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
40 if (node->tree->attributes & HFS_TREE_BIGKEYS)
41 retval = node->tree->max_key_len + 2;
42 else
43 retval = node->tree->max_key_len + 1;
44 } else {
45 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
46 if (!recoff)
47 return 0;
48 if (node->tree->attributes & HFS_TREE_BIGKEYS) {
49 retval = hfs_bnode_read_u16(node, recoff) + 2;
50 if (retval > node->tree->max_key_len + 2) {
51 pr_err("keylen %d too large\n", retval);
52 retval = 0;
53 }
54 } else {
55 retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
56 if (retval > node->tree->max_key_len + 1) {
57 pr_err("keylen %d too large\n", retval);
58 retval = 0;
59 }
60 }
61 }
62 return retval;
63 }
64
65 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
66 {
67 struct hfs_btree *tree;
68 struct hfs_bnode *node, *new_node;
69 int size, key_len, rec;
70 int data_off, end_off;
71 int idx_rec_off, data_rec_off, end_rec_off;
72 __be32 cnid;
73
74 tree = fd->tree;
75 if (!fd->bnode) {
76 if (!tree->root)
77 hfs_btree_inc_height(tree);
78 node = hfs_bnode_find(tree, tree->leaf_head);
79 if (IS_ERR(node))
80 return PTR_ERR(node);
81 fd->bnode = node;
82 fd->record = -1;
83 }
84 new_node = NULL;
85 key_len = (fd->search_key->key_len | 1) + 1;
86 again:
87 /* new record idx and complete record size */
88 rec = fd->record + 1;
89 size = key_len + entry_len;
90
91 node = fd->bnode;
92 hfs_bnode_dump(node);
93 /* get last offset */
94 end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
95 end_off = hfs_bnode_read_u16(node, end_rec_off);
96 end_rec_off -= 2;
97 hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
98 rec, size, end_off, end_rec_off);
99 if (size > end_rec_off - end_off) {
100 if (new_node)
101 panic("not enough room!\n");
102 new_node = hfs_bnode_split(fd);
103 if (IS_ERR(new_node))
104 return PTR_ERR(new_node);
105 goto again;
106 }
107 if (node->type == HFS_NODE_LEAF) {
108 tree->leaf_count++;
109 mark_inode_dirty(tree->inode);
110 }
111 node->num_recs++;
112 /* write new last offset */
113 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
114 hfs_bnode_write_u16(node, end_rec_off, end_off + size);
115 data_off = end_off;
116 data_rec_off = end_rec_off + 2;
117 idx_rec_off = tree->node_size - (rec + 1) * 2;
118 if (idx_rec_off == data_rec_off)
119 goto skip;
120 /* move all following entries */
121 do {
122 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
123 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
124 data_rec_off += 2;
125 } while (data_rec_off < idx_rec_off);
126
127 /* move data away */
128 hfs_bnode_move(node, data_off + size, data_off,
129 end_off - data_off);
130
131 skip:
132 hfs_bnode_write(node, fd->search_key, data_off, key_len);
133 hfs_bnode_write(node, entry, data_off + key_len, entry_len);
134 hfs_bnode_dump(node);
135
136 /*
137 * update parent key if we inserted a key
138 * at the start of the node and it is not the new node
139 */
140 if (!rec && new_node != node) {
141 hfs_bnode_read_key(node, fd->search_key, data_off + size);
142 hfs_brec_update_parent(fd);
143 }
144
145 if (new_node) {
146 hfs_bnode_put(fd->bnode);
147 if (!new_node->parent) {
148 hfs_btree_inc_height(tree);
149 new_node->parent = tree->root;
150 }
151 fd->bnode = hfs_bnode_find(tree, new_node->parent);
152
153 /* create index data entry */
154 cnid = cpu_to_be32(new_node->this);
155 entry = &cnid;
156 entry_len = sizeof(cnid);
157
158 /* get index key */
159 hfs_bnode_read_key(new_node, fd->search_key, 14);
160 __hfs_brec_find(fd->bnode, fd);
161
162 hfs_bnode_put(new_node);
163 new_node = NULL;
164
165 if (tree->attributes & HFS_TREE_VARIDXKEYS)
166 key_len = fd->search_key->key_len + 1;
167 else {
168 fd->search_key->key_len = tree->max_key_len;
169 key_len = tree->max_key_len + 1;
170 }
171 goto again;
172 }
173
174 return 0;
175 }
176
177 int hfs_brec_remove(struct hfs_find_data *fd)
178 {
179 struct hfs_btree *tree;
180 struct hfs_bnode *node, *parent;
181 int end_off, rec_off, data_off, size;
182
183 tree = fd->tree;
184 node = fd->bnode;
185 again:
186 rec_off = tree->node_size - (fd->record + 2) * 2;
187 end_off = tree->node_size - (node->num_recs + 1) * 2;
188
189 if (node->type == HFS_NODE_LEAF) {
190 tree->leaf_count--;
191 mark_inode_dirty(tree->inode);
192 }
193 hfs_bnode_dump(node);
194 hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
195 fd->record, fd->keylength + fd->entrylength);
196 if (!--node->num_recs) {
197 hfs_bnode_unlink(node);
198 if (!node->parent)
199 return 0;
200 parent = hfs_bnode_find(tree, node->parent);
201 if (IS_ERR(parent))
202 return PTR_ERR(parent);
203 hfs_bnode_put(node);
204 node = fd->bnode = parent;
205
206 __hfs_brec_find(node, fd);
207 goto again;
208 }
209 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
210
211 if (rec_off == end_off)
212 goto skip;
213 size = fd->keylength + fd->entrylength;
214
215 do {
216 data_off = hfs_bnode_read_u16(node, rec_off);
217 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
218 rec_off -= 2;
219 } while (rec_off >= end_off);
220
221 /* fill hole */
222 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
223 data_off - fd->keyoffset - size);
224 skip:
225 hfs_bnode_dump(node);
226 if (!fd->record)
227 hfs_brec_update_parent(fd);
228 return 0;
229 }
230
231 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
232 {
233 struct hfs_btree *tree;
234 struct hfs_bnode *node, *new_node, *next_node;
235 struct hfs_bnode_desc node_desc;
236 int num_recs, new_rec_off, new_off, old_rec_off;
237 int data_start, data_end, size;
238
239 tree = fd->tree;
240 node = fd->bnode;
241 new_node = hfs_bmap_alloc(tree);
242 if (IS_ERR(new_node))
243 return new_node;
244 hfs_bnode_get(node);
245 hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
246 node->this, new_node->this, node->next);
247 new_node->next = node->next;
248 new_node->prev = node->this;
249 new_node->parent = node->parent;
250 new_node->type = node->type;
251 new_node->height = node->height;
252
253 if (node->next)
254 next_node = hfs_bnode_find(tree, node->next);
255 else
256 next_node = NULL;
257
258 if (IS_ERR(next_node)) {
259 hfs_bnode_put(node);
260 hfs_bnode_put(new_node);
261 return next_node;
262 }
263
264 size = tree->node_size / 2 - node->num_recs * 2 - 14;
265 old_rec_off = tree->node_size - 4;
266 num_recs = 1;
267 for (;;) {
268 data_start = hfs_bnode_read_u16(node, old_rec_off);
269 if (data_start > size)
270 break;
271 old_rec_off -= 2;
272 if (++num_recs < node->num_recs)
273 continue;
274 /* panic? */
275 hfs_bnode_put(node);
276 hfs_bnode_put(new_node);
277 if (next_node)
278 hfs_bnode_put(next_node);
279 return ERR_PTR(-ENOSPC);
280 }
281
282 if (fd->record + 1 < num_recs) {
283 /* new record is in the lower half,
284 * so leave some more space there
285 */
286 old_rec_off += 2;
287 num_recs--;
288 data_start = hfs_bnode_read_u16(node, old_rec_off);
289 } else {
290 hfs_bnode_put(node);
291 hfs_bnode_get(new_node);
292 fd->bnode = new_node;
293 fd->record -= num_recs;
294 fd->keyoffset -= data_start - 14;
295 fd->entryoffset -= data_start - 14;
296 }
297 new_node->num_recs = node->num_recs - num_recs;
298 node->num_recs = num_recs;
299
300 new_rec_off = tree->node_size - 2;
301 new_off = 14;
302 size = data_start - new_off;
303 num_recs = new_node->num_recs;
304 data_end = data_start;
305 while (num_recs) {
306 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
307 old_rec_off -= 2;
308 new_rec_off -= 2;
309 data_end = hfs_bnode_read_u16(node, old_rec_off);
310 new_off = data_end - size;
311 num_recs--;
312 }
313 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
314 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
315
316 /* update new bnode header */
317 node_desc.next = cpu_to_be32(new_node->next);
318 node_desc.prev = cpu_to_be32(new_node->prev);
319 node_desc.type = new_node->type;
320 node_desc.height = new_node->height;
321 node_desc.num_recs = cpu_to_be16(new_node->num_recs);
322 node_desc.reserved = 0;
323 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
324
325 /* update previous bnode header */
326 node->next = new_node->this;
327 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
328 node_desc.next = cpu_to_be32(node->next);
329 node_desc.num_recs = cpu_to_be16(node->num_recs);
330 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
331
332 /* update next bnode header */
333 if (next_node) {
334 next_node->prev = new_node->this;
335 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
336 node_desc.prev = cpu_to_be32(next_node->prev);
337 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
338 hfs_bnode_put(next_node);
339 } else if (node->this == tree->leaf_tail) {
340 /* if there is no next node, this might be the new tail */
341 tree->leaf_tail = new_node->this;
342 mark_inode_dirty(tree->inode);
343 }
344
345 hfs_bnode_dump(node);
346 hfs_bnode_dump(new_node);
347 hfs_bnode_put(node);
348
349 return new_node;
350 }
351
352 static int hfs_brec_update_parent(struct hfs_find_data *fd)
353 {
354 struct hfs_btree *tree;
355 struct hfs_bnode *node, *new_node, *parent;
356 int newkeylen, diff;
357 int rec, rec_off, end_rec_off;
358 int start_off, end_off;
359
360 tree = fd->tree;
361 node = fd->bnode;
362 new_node = NULL;
363 if (!node->parent)
364 return 0;
365
366 again:
367 parent = hfs_bnode_find(tree, node->parent);
368 if (IS_ERR(parent))
369 return PTR_ERR(parent);
370 __hfs_brec_find(parent, fd);
371 if (fd->record < 0)
372 return -ENOENT;
373 hfs_bnode_dump(parent);
374 rec = fd->record;
375
376 /* size difference between old and new key */
377 if (tree->attributes & HFS_TREE_VARIDXKEYS)
378 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
379 else
380 fd->keylength = newkeylen = tree->max_key_len + 1;
381 hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
382 rec, fd->keylength, newkeylen);
383
384 rec_off = tree->node_size - (rec + 2) * 2;
385 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
386 diff = newkeylen - fd->keylength;
387 if (!diff)
388 goto skip;
389 if (diff > 0) {
390 end_off = hfs_bnode_read_u16(parent, end_rec_off);
391 if (end_rec_off - end_off < diff) {
392
393 printk(KERN_DEBUG "splitting index node...\n");
394 fd->bnode = parent;
395 new_node = hfs_bnode_split(fd);
396 if (IS_ERR(new_node))
397 return PTR_ERR(new_node);
398 parent = fd->bnode;
399 rec = fd->record;
400 rec_off = tree->node_size - (rec + 2) * 2;
401 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
402 }
403 }
404
405 end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
406 hfs_bnode_write_u16(parent, rec_off, start_off + diff);
407 start_off -= 4; /* move previous cnid too */
408
409 while (rec_off > end_rec_off) {
410 rec_off -= 2;
411 end_off = hfs_bnode_read_u16(parent, rec_off);
412 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
413 }
414 hfs_bnode_move(parent, start_off + diff, start_off,
415 end_off - start_off);
416 skip:
417 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
418 if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
419 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
420 hfs_bnode_dump(parent);
421
422 hfs_bnode_put(node);
423 node = parent;
424
425 if (new_node) {
426 __be32 cnid;
427
428 if (!new_node->parent) {
429 hfs_btree_inc_height(tree);
430 new_node->parent = tree->root;
431 }
432 fd->bnode = hfs_bnode_find(tree, new_node->parent);
433 /* create index key and entry */
434 hfs_bnode_read_key(new_node, fd->search_key, 14);
435 cnid = cpu_to_be32(new_node->this);
436
437 __hfs_brec_find(fd->bnode, fd);
438 hfs_brec_insert(fd, &cnid, sizeof(cnid));
439 hfs_bnode_put(fd->bnode);
440 hfs_bnode_put(new_node);
441
442 if (!rec) {
443 if (new_node == node)
444 goto out;
445 /* restore search_key */
446 hfs_bnode_read_key(node, fd->search_key, 14);
447 }
448 new_node = NULL;
449 }
450
451 if (!rec && node->parent)
452 goto again;
453 out:
454 fd->bnode = node;
455 return 0;
456 }
457
458 static int hfs_btree_inc_height(struct hfs_btree *tree)
459 {
460 struct hfs_bnode *node, *new_node;
461 struct hfs_bnode_desc node_desc;
462 int key_size, rec;
463 __be32 cnid;
464
465 node = NULL;
466 if (tree->root) {
467 node = hfs_bnode_find(tree, tree->root);
468 if (IS_ERR(node))
469 return PTR_ERR(node);
470 }
471 new_node = hfs_bmap_alloc(tree);
472 if (IS_ERR(new_node)) {
473 hfs_bnode_put(node);
474 return PTR_ERR(new_node);
475 }
476
477 tree->root = new_node->this;
478 if (!tree->depth) {
479 tree->leaf_head = tree->leaf_tail = new_node->this;
480 new_node->type = HFS_NODE_LEAF;
481 new_node->num_recs = 0;
482 } else {
483 new_node->type = HFS_NODE_INDEX;
484 new_node->num_recs = 1;
485 }
486 new_node->parent = 0;
487 new_node->next = 0;
488 new_node->prev = 0;
489 new_node->height = ++tree->depth;
490
491 node_desc.next = cpu_to_be32(new_node->next);
492 node_desc.prev = cpu_to_be32(new_node->prev);
493 node_desc.type = new_node->type;
494 node_desc.height = new_node->height;
495 node_desc.num_recs = cpu_to_be16(new_node->num_recs);
496 node_desc.reserved = 0;
497 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
498
499 rec = tree->node_size - 2;
500 hfs_bnode_write_u16(new_node, rec, 14);
501
502 if (node) {
503 /* insert old root idx into new root */
504 node->parent = tree->root;
505 if (node->type == HFS_NODE_LEAF ||
506 tree->attributes & HFS_TREE_VARIDXKEYS)
507 key_size = hfs_bnode_read_u8(node, 14) + 1;
508 else
509 key_size = tree->max_key_len + 1;
510 hfs_bnode_copy(new_node, 14, node, 14, key_size);
511
512 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
513 key_size = tree->max_key_len + 1;
514 hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
515 }
516 key_size = (key_size + 1) & -2;
517 cnid = cpu_to_be32(node->this);
518 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
519
520 rec -= 2;
521 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
522
523 hfs_bnode_put(node);
524 }
525 hfs_bnode_put(new_node);
526 mark_inode_dirty(tree->inode);
527
528 return 0;
529 }
530
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.