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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
11#include "btree.h"
12
13static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
14static int hfs_brec_update_parent(struct hfs_find_data *fd);
15static int hfs_btree_inc_height(struct hfs_btree *tree);
16
17/* Get the length and offset of the given record in the given node */
18u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
19{
20 __be16 retval[2];
21 u16 dataoff;
22
23 dataoff = node->tree->node_size - (rec + 2) * 2;
24 hfs_bnode_read(node, retval, dataoff, 4);
25 *off = be16_to_cpu(retval[1]);
26 return be16_to_cpu(retval[0]) - *off;
27}
28
29/* Get the length of the key from a keyed record */
30u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
31{
32 u16 retval, recoff;
33
34 if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
35 return 0;
36
37 if ((node->type == HFS_NODE_INDEX) &&
38 !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
39 if (node->tree->attributes & HFS_TREE_BIGKEYS)
40 retval = node->tree->max_key_len + 2;
41 else
42 retval = node->tree->max_key_len + 1;
43 } else {
44 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
45 if (!recoff)
46 return 0;
47 if (node->tree->attributes & HFS_TREE_BIGKEYS)
48 retval = hfs_bnode_read_u16(node, recoff) + 2;
49 else
50 retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
51 }
52 return retval;
53}
54
55int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
56{
57 struct hfs_btree *tree;
58 struct hfs_bnode *node, *new_node;
59 int size, key_len, rec;
60 int data_off, end_off;
61 int idx_rec_off, data_rec_off, end_rec_off;
62 __be32 cnid;
63
64 tree = fd->tree;
65 if (!fd->bnode) {
66 if (!tree->root)
67 hfs_btree_inc_height(tree);
68 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
69 if (IS_ERR(fd->bnode))
70 return PTR_ERR(fd->bnode);
71 fd->record = -1;
72 }
73 new_node = NULL;
74 key_len = (fd->search_key->key_len | 1) + 1;
75again:
76 /* new record idx and complete record size */
77 rec = fd->record + 1;
78 size = key_len + entry_len;
79
80 node = fd->bnode;
81 hfs_bnode_dump(node);
82 /* get last offset */
83 end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
84 end_off = hfs_bnode_read_u16(node, end_rec_off);
85 end_rec_off -= 2;
86 dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
87 if (size > end_rec_off - end_off) {
88 if (new_node)
89 panic("not enough room!\n");
90 new_node = hfs_bnode_split(fd);
91 if (IS_ERR(new_node))
92 return PTR_ERR(new_node);
93 goto again;
94 }
95 if (node->type == HFS_NODE_LEAF) {
96 tree->leaf_count++;
97 mark_inode_dirty(tree->inode);
98 }
99 node->num_recs++;
100 /* write new last offset */
101 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
102 hfs_bnode_write_u16(node, end_rec_off, end_off + size);
103 data_off = end_off;
104 data_rec_off = end_rec_off + 2;
105 idx_rec_off = tree->node_size - (rec + 1) * 2;
106 if (idx_rec_off == data_rec_off)
107 goto skip;
108 /* move all following entries */
109 do {
110 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
111 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
112 data_rec_off += 2;
113 } while (data_rec_off < idx_rec_off);
114
115 /* move data away */
116 hfs_bnode_move(node, data_off + size, data_off,
117 end_off - data_off);
118
119skip:
120 hfs_bnode_write(node, fd->search_key, data_off, key_len);
121 hfs_bnode_write(node, entry, data_off + key_len, entry_len);
122 hfs_bnode_dump(node);
123
124 if (new_node) {
125 /* update parent key if we inserted a key
126 * at the start of the first node
127 */
128 if (!rec && new_node != node)
129 hfs_brec_update_parent(fd);
130
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
138 /* create index data entry */
139 cnid = cpu_to_be32(new_node->this);
140 entry = &cnid;
141 entry_len = sizeof(cnid);
142
143 /* get index key */
144 hfs_bnode_read_key(new_node, fd->search_key, 14);
145 __hfs_brec_find(fd->bnode, fd);
146
147 hfs_bnode_put(new_node);
148 new_node = NULL;
149
150 if (tree->attributes & HFS_TREE_VARIDXKEYS)
151 key_len = fd->search_key->key_len + 1;
152 else {
153 fd->search_key->key_len = tree->max_key_len;
154 key_len = tree->max_key_len + 1;
155 }
156 goto again;
157 }
158
159 if (!rec)
160 hfs_brec_update_parent(fd);
161
162 return 0;
163}
164
165int hfs_brec_remove(struct hfs_find_data *fd)
166{
167 struct hfs_btree *tree;
168 struct hfs_bnode *node, *parent;
169 int end_off, rec_off, data_off, size;
170
171 tree = fd->tree;
172 node = fd->bnode;
173again:
174 rec_off = tree->node_size - (fd->record + 2) * 2;
175 end_off = tree->node_size - (node->num_recs + 1) * 2;
176
177 if (node->type == HFS_NODE_LEAF) {
178 tree->leaf_count--;
179 mark_inode_dirty(tree->inode);
180 }
181 hfs_bnode_dump(node);
182 dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
183 if (!--node->num_recs) {
184 hfs_bnode_unlink(node);
185 if (!node->parent)
186 return 0;
187 parent = hfs_bnode_find(tree, node->parent);
188 if (IS_ERR(parent))
189 return PTR_ERR(parent);
190 hfs_bnode_put(node);
191 node = fd->bnode = parent;
192
193 __hfs_brec_find(node, fd);
194 goto again;
195 }
196 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
197
198 if (rec_off == end_off)
199 goto skip;
200 size = fd->keylength + fd->entrylength;
201
202 do {
203 data_off = hfs_bnode_read_u16(node, rec_off);
204 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
205 rec_off -= 2;
206 } while (rec_off >= end_off);
207
208 /* fill hole */
209 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
210 data_off - fd->keyoffset - size);
211skip:
212 hfs_bnode_dump(node);
213 if (!fd->record)
214 hfs_brec_update_parent(fd);
215 return 0;
216}
217
218static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
219{
220 struct hfs_btree *tree;
221 struct hfs_bnode *node, *new_node;
222 struct hfs_bnode_desc node_desc;
223 int num_recs, new_rec_off, new_off, old_rec_off;
224 int data_start, data_end, size;
225
226 tree = fd->tree;
227 node = fd->bnode;
228 new_node = hfs_bmap_alloc(tree);
229 if (IS_ERR(new_node))
230 return new_node;
231 hfs_bnode_get(node);
232 dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
233 node->this, new_node->this, node->next);
234 new_node->next = node->next;
235 new_node->prev = node->this;
236 new_node->parent = node->parent;
237 new_node->type = node->type;
238 new_node->height = node->height;
239
240 size = tree->node_size / 2 - node->num_recs * 2 - 14;
241 old_rec_off = tree->node_size - 4;
242 num_recs = 1;
243 for (;;) {
244 data_start = hfs_bnode_read_u16(node, old_rec_off);
245 if (data_start > size)
246 break;
247 old_rec_off -= 2;
248 if (++num_recs < node->num_recs)
249 continue;
250 /* panic? */
251 hfs_bnode_put(node);
252 hfs_bnode_put(new_node);
253 return ERR_PTR(-ENOSPC);
254 }
255
256 if (fd->record + 1 < num_recs) {
257 /* new record is in the lower half,
258 * so leave some more space there
259 */
260 old_rec_off += 2;
261 num_recs--;
262 data_start = hfs_bnode_read_u16(node, old_rec_off);
263 } else {
264 hfs_bnode_put(node);
265 hfs_bnode_get(new_node);
266 fd->bnode = new_node;
267 fd->record -= num_recs;
268 fd->keyoffset -= data_start - 14;
269 fd->entryoffset -= data_start - 14;
270 }
271 new_node->num_recs = node->num_recs - num_recs;
272 node->num_recs = num_recs;
273
274 new_rec_off = tree->node_size - 2;
275 new_off = 14;
276 size = data_start - new_off;
277 num_recs = new_node->num_recs;
278 data_end = data_start;
279 while (num_recs) {
280 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
281 old_rec_off -= 2;
282 new_rec_off -= 2;
283 data_end = hfs_bnode_read_u16(node, old_rec_off);
284 new_off = data_end - size;
285 num_recs--;
286 }
287 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
288 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
289
290 /* update new bnode header */
291 node_desc.next = cpu_to_be32(new_node->next);
292 node_desc.prev = cpu_to_be32(new_node->prev);
293 node_desc.type = new_node->type;
294 node_desc.height = new_node->height;
295 node_desc.num_recs = cpu_to_be16(new_node->num_recs);
296 node_desc.reserved = 0;
297 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
298
299 /* update previous bnode header */
300 node->next = new_node->this;
301 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
302 node_desc.next = cpu_to_be32(node->next);
303 node_desc.num_recs = cpu_to_be16(node->num_recs);
304 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
305
306 /* update next bnode header */
307 if (new_node->next) {
308 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
309 next_node->prev = new_node->this;
310 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
311 node_desc.prev = cpu_to_be32(next_node->prev);
312 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
313 hfs_bnode_put(next_node);
314 } else if (node->this == tree->leaf_tail) {
315 /* if there is no next node, this might be the new tail */
316 tree->leaf_tail = new_node->this;
317 mark_inode_dirty(tree->inode);
318 }
319
320 hfs_bnode_dump(node);
321 hfs_bnode_dump(new_node);
322 hfs_bnode_put(node);
323
324 return new_node;
325}
326
327static int hfs_brec_update_parent(struct hfs_find_data *fd)
328{
329 struct hfs_btree *tree;
330 struct hfs_bnode *node, *new_node, *parent;
331 int newkeylen, diff;
332 int rec, rec_off, end_rec_off;
333 int start_off, end_off;
334
335 tree = fd->tree;
336 node = fd->bnode;
337 new_node = NULL;
338 if (!node->parent)
339 return 0;
340
341again:
342 parent = hfs_bnode_find(tree, node->parent);
343 if (IS_ERR(parent))
344 return PTR_ERR(parent);
345 __hfs_brec_find(parent, fd);
346 hfs_bnode_dump(parent);
347 rec = fd->record;
348
349 /* size difference between old and new key */
350 if (tree->attributes & HFS_TREE_VARIDXKEYS)
351 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
352 else
353 fd->keylength = newkeylen = tree->max_key_len + 1;
354 dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
355
356 rec_off = tree->node_size - (rec + 2) * 2;
357 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
358 diff = newkeylen - fd->keylength;
359 if (!diff)
360 goto skip;
361 if (diff > 0) {
362 end_off = hfs_bnode_read_u16(parent, end_rec_off);
363 if (end_rec_off - end_off < diff) {
364
365 printk("splitting index node...\n");
366 fd->bnode = parent;
367 new_node = hfs_bnode_split(fd);
368 if (IS_ERR(new_node))
369 return PTR_ERR(new_node);
370 parent = fd->bnode;
371 rec = fd->record;
372 rec_off = tree->node_size - (rec + 2) * 2;
373 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
374 }
375 }
376
377 end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
378 hfs_bnode_write_u16(parent, rec_off, start_off + diff);
379 start_off -= 4; /* move previous cnid too */
380
381 while (rec_off > end_rec_off) {
382 rec_off -= 2;
383 end_off = hfs_bnode_read_u16(parent, rec_off);
384 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
385 }
386 hfs_bnode_move(parent, start_off + diff, start_off,
387 end_off - start_off);
388skip:
389 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
390 if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
391 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
392 hfs_bnode_dump(parent);
393
394 hfs_bnode_put(node);
395 node = parent;
396
397 if (new_node) {
398 __be32 cnid;
399
400 fd->bnode = hfs_bnode_find(tree, new_node->parent);
401 /* create index key and entry */
402 hfs_bnode_read_key(new_node, fd->search_key, 14);
403 cnid = cpu_to_be32(new_node->this);
404
405 __hfs_brec_find(fd->bnode, fd);
406 hfs_brec_insert(fd, &cnid, sizeof(cnid));
407 hfs_bnode_put(fd->bnode);
408 hfs_bnode_put(new_node);
409
410 if (!rec) {
411 if (new_node == node)
412 goto out;
413 /* restore search_key */
414 hfs_bnode_read_key(node, fd->search_key, 14);
415 }
416 }
417
418 if (!rec && node->parent)
419 goto again;
420out:
421 fd->bnode = node;
422 return 0;
423}
424
425static int hfs_btree_inc_height(struct hfs_btree *tree)
426{
427 struct hfs_bnode *node, *new_node;
428 struct hfs_bnode_desc node_desc;
429 int key_size, rec;
430 __be32 cnid;
431
432 node = NULL;
433 if (tree->root) {
434 node = hfs_bnode_find(tree, tree->root);
435 if (IS_ERR(node))
436 return PTR_ERR(node);
437 }
438 new_node = hfs_bmap_alloc(tree);
439 if (IS_ERR(new_node)) {
440 hfs_bnode_put(node);
441 return PTR_ERR(new_node);
442 }
443
444 tree->root = new_node->this;
445 if (!tree->depth) {
446 tree->leaf_head = tree->leaf_tail = new_node->this;
447 new_node->type = HFS_NODE_LEAF;
448 new_node->num_recs = 0;
449 } else {
450 new_node->type = HFS_NODE_INDEX;
451 new_node->num_recs = 1;
452 }
453 new_node->parent = 0;
454 new_node->next = 0;
455 new_node->prev = 0;
456 new_node->height = ++tree->depth;
457
458 node_desc.next = cpu_to_be32(new_node->next);
459 node_desc.prev = cpu_to_be32(new_node->prev);
460 node_desc.type = new_node->type;
461 node_desc.height = new_node->height;
462 node_desc.num_recs = cpu_to_be16(new_node->num_recs);
463 node_desc.reserved = 0;
464 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
465
466 rec = tree->node_size - 2;
467 hfs_bnode_write_u16(new_node, rec, 14);
468
469 if (node) {
470 /* insert old root idx into new root */
471 node->parent = tree->root;
472 if (node->type == HFS_NODE_LEAF ||
473 tree->attributes & HFS_TREE_VARIDXKEYS)
474 key_size = hfs_bnode_read_u8(node, 14) + 1;
475 else
476 key_size = tree->max_key_len + 1;
477 hfs_bnode_copy(new_node, 14, node, 14, key_size);
478
479 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
480 key_size = tree->max_key_len + 1;
481 hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
482 }
483 key_size = (key_size + 1) & -2;
484 cnid = cpu_to_be32(node->this);
485 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
486
487 rec -= 2;
488 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
489
490 hfs_bnode_put(node);
491 }
492 hfs_bnode_put(new_node);
493 mark_inode_dirty(tree->inode);
494
495 return 0;
496}