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