xref: /openbmc/linux/fs/hfsplus/brec.c (revision 4800cd83)
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 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 *);
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 		retval = node->tree->max_key_len + 2;
41 	} else {
42 		recoff = hfs_bnode_read_u16(node,
43 			node->tree->node_size - (rec + 1) * 2);
44 		if (!recoff)
45 			return 0;
46 
47 		retval = hfs_bnode_read_u16(node, recoff) + 2;
48 		if (retval > node->tree->max_key_len + 2) {
49 			printk(KERN_ERR "hfs: keylen %d too large\n",
50 				retval);
51 			retval = 0;
52 		}
53 	}
54 	return retval;
55 }
56 
57 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
58 {
59 	struct hfs_btree *tree;
60 	struct hfs_bnode *node, *new_node;
61 	int size, key_len, rec;
62 	int data_off, end_off;
63 	int idx_rec_off, data_rec_off, end_rec_off;
64 	__be32 cnid;
65 
66 	tree = fd->tree;
67 	if (!fd->bnode) {
68 		if (!tree->root)
69 			hfs_btree_inc_height(tree);
70 		fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
71 		if (IS_ERR(fd->bnode))
72 			return PTR_ERR(fd->bnode);
73 		fd->record = -1;
74 	}
75 	new_node = NULL;
76 	key_len = be16_to_cpu(fd->search_key->key_len) + 2;
77 again:
78 	/* new record idx and complete record size */
79 	rec = fd->record + 1;
80 	size = key_len + entry_len;
81 
82 	node = fd->bnode;
83 	hfs_bnode_dump(node);
84 	/* get last offset */
85 	end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
86 	end_off = hfs_bnode_read_u16(node, end_rec_off);
87 	end_rec_off -= 2;
88 	dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
89 		rec, size, end_off, end_rec_off);
90 	if (size > end_rec_off - end_off) {
91 		if (new_node)
92 			panic("not enough room!\n");
93 		new_node = hfs_bnode_split(fd);
94 		if (IS_ERR(new_node))
95 			return PTR_ERR(new_node);
96 		goto again;
97 	}
98 	if (node->type == HFS_NODE_LEAF) {
99 		tree->leaf_count++;
100 		mark_inode_dirty(tree->inode);
101 	}
102 	node->num_recs++;
103 	/* write new last offset */
104 	hfs_bnode_write_u16(node,
105 		offsetof(struct hfs_bnode_desc, num_recs),
106 		node->num_recs);
107 	hfs_bnode_write_u16(node, end_rec_off, end_off + size);
108 	data_off = end_off;
109 	data_rec_off = end_rec_off + 2;
110 	idx_rec_off = tree->node_size - (rec + 1) * 2;
111 	if (idx_rec_off == data_rec_off)
112 		goto skip;
113 	/* move all following entries */
114 	do {
115 		data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
116 		hfs_bnode_write_u16(node, data_rec_off, data_off + size);
117 		data_rec_off += 2;
118 	} while (data_rec_off < idx_rec_off);
119 
120 	/* move data away */
121 	hfs_bnode_move(node, data_off + size, data_off,
122 		       end_off - data_off);
123 
124 skip:
125 	hfs_bnode_write(node, fd->search_key, data_off, key_len);
126 	hfs_bnode_write(node, entry, data_off + key_len, entry_len);
127 	hfs_bnode_dump(node);
128 
129 	if (new_node) {
130 		/* update parent key if we inserted a key
131 		 * at the start of the first node
132 		 */
133 		if (!rec && new_node != node)
134 			hfs_brec_update_parent(fd);
135 
136 		hfs_bnode_put(fd->bnode);
137 		if (!new_node->parent) {
138 			hfs_btree_inc_height(tree);
139 			new_node->parent = tree->root;
140 		}
141 		fd->bnode = hfs_bnode_find(tree, new_node->parent);
142 
143 		/* create index data entry */
144 		cnid = cpu_to_be32(new_node->this);
145 		entry = &cnid;
146 		entry_len = sizeof(cnid);
147 
148 		/* get index key */
149 		hfs_bnode_read_key(new_node, fd->search_key, 14);
150 		__hfs_brec_find(fd->bnode, fd);
151 
152 		hfs_bnode_put(new_node);
153 		new_node = NULL;
154 
155 		if (tree->attributes & HFS_TREE_VARIDXKEYS)
156 			key_len = be16_to_cpu(fd->search_key->key_len) + 2;
157 		else {
158 			fd->search_key->key_len =
159 				cpu_to_be16(tree->max_key_len);
160 			key_len = tree->max_key_len + 2;
161 		}
162 		goto again;
163 	}
164 
165 	if (!rec)
166 		hfs_brec_update_parent(fd);
167 
168 	return 0;
169 }
170 
171 int hfs_brec_remove(struct hfs_find_data *fd)
172 {
173 	struct hfs_btree *tree;
174 	struct hfs_bnode *node, *parent;
175 	int end_off, rec_off, data_off, size;
176 
177 	tree = fd->tree;
178 	node = fd->bnode;
179 again:
180 	rec_off = tree->node_size - (fd->record + 2) * 2;
181 	end_off = tree->node_size - (node->num_recs + 1) * 2;
182 
183 	if (node->type == HFS_NODE_LEAF) {
184 		tree->leaf_count--;
185 		mark_inode_dirty(tree->inode);
186 	}
187 	hfs_bnode_dump(node);
188 	dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n",
189 		fd->record, fd->keylength + fd->entrylength);
190 	if (!--node->num_recs) {
191 		hfs_bnode_unlink(node);
192 		if (!node->parent)
193 			return 0;
194 		parent = hfs_bnode_find(tree, node->parent);
195 		if (IS_ERR(parent))
196 			return PTR_ERR(parent);
197 		hfs_bnode_put(node);
198 		node = fd->bnode = parent;
199 
200 		__hfs_brec_find(node, fd);
201 		goto again;
202 	}
203 	hfs_bnode_write_u16(node,
204 		offsetof(struct hfs_bnode_desc, num_recs),
205 		node->num_recs);
206 
207 	if (rec_off == end_off)
208 		goto skip;
209 	size = fd->keylength + fd->entrylength;
210 
211 	do {
212 		data_off = hfs_bnode_read_u16(node, rec_off);
213 		hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
214 		rec_off -= 2;
215 	} while (rec_off >= end_off);
216 
217 	/* fill hole */
218 	hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
219 		       data_off - fd->keyoffset - size);
220 skip:
221 	hfs_bnode_dump(node);
222 	if (!fd->record)
223 		hfs_brec_update_parent(fd);
224 	return 0;
225 }
226 
227 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
228 {
229 	struct hfs_btree *tree;
230 	struct hfs_bnode *node, *new_node, *next_node;
231 	struct hfs_bnode_desc node_desc;
232 	int num_recs, new_rec_off, new_off, old_rec_off;
233 	int data_start, data_end, size;
234 
235 	tree = fd->tree;
236 	node = fd->bnode;
237 	new_node = hfs_bmap_alloc(tree);
238 	if (IS_ERR(new_node))
239 		return new_node;
240 	hfs_bnode_get(node);
241 	dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
242 		node->this, new_node->this, node->next);
243 	new_node->next = node->next;
244 	new_node->prev = node->this;
245 	new_node->parent = node->parent;
246 	new_node->type = node->type;
247 	new_node->height = node->height;
248 
249 	if (node->next)
250 		next_node = hfs_bnode_find(tree, node->next);
251 	else
252 		next_node = NULL;
253 
254 	if (IS_ERR(next_node)) {
255 		hfs_bnode_put(node);
256 		hfs_bnode_put(new_node);
257 		return next_node;
258 	}
259 
260 	size = tree->node_size / 2 - node->num_recs * 2 - 14;
261 	old_rec_off = tree->node_size - 4;
262 	num_recs = 1;
263 	for (;;) {
264 		data_start = hfs_bnode_read_u16(node, old_rec_off);
265 		if (data_start > size)
266 			break;
267 		old_rec_off -= 2;
268 		if (++num_recs < node->num_recs)
269 			continue;
270 		/* panic? */
271 		hfs_bnode_put(node);
272 		hfs_bnode_put(new_node);
273 		if (next_node)
274 			hfs_bnode_put(next_node);
275 		return ERR_PTR(-ENOSPC);
276 	}
277 
278 	if (fd->record + 1 < num_recs) {
279 		/* new record is in the lower half,
280 		 * so leave some more space there
281 		 */
282 		old_rec_off += 2;
283 		num_recs--;
284 		data_start = hfs_bnode_read_u16(node, old_rec_off);
285 	} else {
286 		hfs_bnode_put(node);
287 		hfs_bnode_get(new_node);
288 		fd->bnode = new_node;
289 		fd->record -= num_recs;
290 		fd->keyoffset -= data_start - 14;
291 		fd->entryoffset -= data_start - 14;
292 	}
293 	new_node->num_recs = node->num_recs - num_recs;
294 	node->num_recs = num_recs;
295 
296 	new_rec_off = tree->node_size - 2;
297 	new_off = 14;
298 	size = data_start - new_off;
299 	num_recs = new_node->num_recs;
300 	data_end = data_start;
301 	while (num_recs) {
302 		hfs_bnode_write_u16(new_node, new_rec_off, new_off);
303 		old_rec_off -= 2;
304 		new_rec_off -= 2;
305 		data_end = hfs_bnode_read_u16(node, old_rec_off);
306 		new_off = data_end - size;
307 		num_recs--;
308 	}
309 	hfs_bnode_write_u16(new_node, new_rec_off, new_off);
310 	hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
311 
312 	/* update new bnode header */
313 	node_desc.next = cpu_to_be32(new_node->next);
314 	node_desc.prev = cpu_to_be32(new_node->prev);
315 	node_desc.type = new_node->type;
316 	node_desc.height = new_node->height;
317 	node_desc.num_recs = cpu_to_be16(new_node->num_recs);
318 	node_desc.reserved = 0;
319 	hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
320 
321 	/* update previous bnode header */
322 	node->next = new_node->this;
323 	hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
324 	node_desc.next = cpu_to_be32(node->next);
325 	node_desc.num_recs = cpu_to_be16(node->num_recs);
326 	hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
327 
328 	/* update next bnode header */
329 	if (next_node) {
330 		next_node->prev = new_node->this;
331 		hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
332 		node_desc.prev = cpu_to_be32(next_node->prev);
333 		hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
334 		hfs_bnode_put(next_node);
335 	} else if (node->this == tree->leaf_tail) {
336 		/* if there is no next node, this might be the new tail */
337 		tree->leaf_tail = new_node->this;
338 		mark_inode_dirty(tree->inode);
339 	}
340 
341 	hfs_bnode_dump(node);
342 	hfs_bnode_dump(new_node);
343 	hfs_bnode_put(node);
344 
345 	return new_node;
346 }
347 
348 static int hfs_brec_update_parent(struct hfs_find_data *fd)
349 {
350 	struct hfs_btree *tree;
351 	struct hfs_bnode *node, *new_node, *parent;
352 	int newkeylen, diff;
353 	int rec, rec_off, end_rec_off;
354 	int start_off, end_off;
355 
356 	tree = fd->tree;
357 	node = fd->bnode;
358 	new_node = NULL;
359 	if (!node->parent)
360 		return 0;
361 
362 again:
363 	parent = hfs_bnode_find(tree, node->parent);
364 	if (IS_ERR(parent))
365 		return PTR_ERR(parent);
366 	__hfs_brec_find(parent, fd);
367 	hfs_bnode_dump(parent);
368 	rec = fd->record;
369 
370 	/* size difference between old and new key */
371 	if (tree->attributes & HFS_TREE_VARIDXKEYS)
372 		newkeylen = hfs_bnode_read_u16(node, 14) + 2;
373 	else
374 		fd->keylength = newkeylen = tree->max_key_len + 2;
375 	dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n",
376 		rec, fd->keylength, newkeylen);
377 
378 	rec_off = tree->node_size - (rec + 2) * 2;
379 	end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
380 	diff = newkeylen - fd->keylength;
381 	if (!diff)
382 		goto skip;
383 	if (diff > 0) {
384 		end_off = hfs_bnode_read_u16(parent, end_rec_off);
385 		if (end_rec_off - end_off < diff) {
386 
387 			dprint(DBG_BNODE_MOD, "hfs: splitting index node.\n");
388 			fd->bnode = parent;
389 			new_node = hfs_bnode_split(fd);
390 			if (IS_ERR(new_node))
391 				return PTR_ERR(new_node);
392 			parent = fd->bnode;
393 			rec = fd->record;
394 			rec_off = tree->node_size - (rec + 2) * 2;
395 			end_rec_off = tree->node_size -
396 				(parent->num_recs + 1) * 2;
397 		}
398 	}
399 
400 	end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
401 	hfs_bnode_write_u16(parent, rec_off, start_off + diff);
402 	start_off -= 4;	/* move previous cnid too */
403 
404 	while (rec_off > end_rec_off) {
405 		rec_off -= 2;
406 		end_off = hfs_bnode_read_u16(parent, rec_off);
407 		hfs_bnode_write_u16(parent, rec_off, end_off + diff);
408 	}
409 	hfs_bnode_move(parent, start_off + diff, start_off,
410 		       end_off - start_off);
411 skip:
412 	hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
413 	hfs_bnode_dump(parent);
414 
415 	hfs_bnode_put(node);
416 	node = parent;
417 
418 	if (new_node) {
419 		__be32 cnid;
420 
421 		fd->bnode = hfs_bnode_find(tree, new_node->parent);
422 		/* create index key and entry */
423 		hfs_bnode_read_key(new_node, fd->search_key, 14);
424 		cnid = cpu_to_be32(new_node->this);
425 
426 		__hfs_brec_find(fd->bnode, fd);
427 		hfs_brec_insert(fd, &cnid, sizeof(cnid));
428 		hfs_bnode_put(fd->bnode);
429 		hfs_bnode_put(new_node);
430 
431 		if (!rec) {
432 			if (new_node == node)
433 				goto out;
434 			/* restore search_key */
435 			hfs_bnode_read_key(node, fd->search_key, 14);
436 		}
437 	}
438 
439 	if (!rec && node->parent)
440 		goto again;
441 out:
442 	fd->bnode = node;
443 	return 0;
444 }
445 
446 static int hfs_btree_inc_height(struct hfs_btree *tree)
447 {
448 	struct hfs_bnode *node, *new_node;
449 	struct hfs_bnode_desc node_desc;
450 	int key_size, rec;
451 	__be32 cnid;
452 
453 	node = NULL;
454 	if (tree->root) {
455 		node = hfs_bnode_find(tree, tree->root);
456 		if (IS_ERR(node))
457 			return PTR_ERR(node);
458 	}
459 	new_node = hfs_bmap_alloc(tree);
460 	if (IS_ERR(new_node)) {
461 		hfs_bnode_put(node);
462 		return PTR_ERR(new_node);
463 	}
464 
465 	tree->root = new_node->this;
466 	if (!tree->depth) {
467 		tree->leaf_head = tree->leaf_tail = new_node->this;
468 		new_node->type = HFS_NODE_LEAF;
469 		new_node->num_recs = 0;
470 	} else {
471 		new_node->type = HFS_NODE_INDEX;
472 		new_node->num_recs = 1;
473 	}
474 	new_node->parent = 0;
475 	new_node->next = 0;
476 	new_node->prev = 0;
477 	new_node->height = ++tree->depth;
478 
479 	node_desc.next = cpu_to_be32(new_node->next);
480 	node_desc.prev = cpu_to_be32(new_node->prev);
481 	node_desc.type = new_node->type;
482 	node_desc.height = new_node->height;
483 	node_desc.num_recs = cpu_to_be16(new_node->num_recs);
484 	node_desc.reserved = 0;
485 	hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
486 
487 	rec = tree->node_size - 2;
488 	hfs_bnode_write_u16(new_node, rec, 14);
489 
490 	if (node) {
491 		/* insert old root idx into new root */
492 		node->parent = tree->root;
493 		if (node->type == HFS_NODE_LEAF ||
494 		    tree->attributes & HFS_TREE_VARIDXKEYS)
495 			key_size = hfs_bnode_read_u16(node, 14) + 2;
496 		else
497 			key_size = tree->max_key_len + 2;
498 		hfs_bnode_copy(new_node, 14, node, 14, key_size);
499 
500 		if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
501 			key_size = tree->max_key_len + 2;
502 			hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
503 		}
504 		cnid = cpu_to_be32(node->this);
505 		hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
506 
507 		rec -= 2;
508 		hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
509 
510 		hfs_bnode_put(node);
511 	}
512 	hfs_bnode_put(new_node);
513 	mark_inode_dirty(tree->inode);
514 
515 	return 0;
516 }
517