bnode.c

  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
 12#include <linux/pagemap.h>
 13#include <linux/slab.h>
 14#include <linux/swap.h>
 15
 16#include "btree.h"
 17
 18static inline
 19bool is_bnode_offset_valid(struct hfs_bnode *node, u32 off)
 20{
 21	bool is_valid = off < node->tree->node_size;
 22
 23	if (!is_valid) {
 24		pr_err("requested invalid offset: "
 25		       "NODE: id %u, type %#x, height %u, "
 26		       "node_size %u, offset %u\n",
 27		       node->this, node->type, node->height,
 28		       node->tree->node_size, off);
 29	}
 30
 31	return is_valid;
 32}
 33
 34static inline
 35u32 check_and_correct_requested_length(struct hfs_bnode *node, u32 off, u32 len)
 36{
 37	unsigned int node_size;
 38
 39	if (!is_bnode_offset_valid(node, off))
 40		return 0;
 41
 42	node_size = node->tree->node_size;
 43
 44	if ((off + len) > node_size) {
 45		u32 new_len = node_size - off;
 46
 47		pr_err("requested length has been corrected: "
 48		       "NODE: id %u, type %#x, height %u, "
 49		       "node_size %u, offset %u, "
 50		       "requested_len %u, corrected_len %u\n",
 51		       node->this, node->type, node->height,
 52		       node->tree->node_size, off, len, new_len);
 53
 54		return new_len;
 55	}
 56
 57	return len;
 58}
 59
 60void hfs_bnode_read(struct hfs_bnode *node, void *buf, u32 off, u32 len)
 61{
 62	struct page *page;
 63	u32 pagenum;
 64	u32 bytes_read;
 65	u32 bytes_to_read;
 66
 67	if (!is_bnode_offset_valid(node, off))
 68		return;
 69
 70	if (len == 0) {
 71		pr_err("requested zero length: "
 72		       "NODE: id %u, type %#x, height %u, "
 73		       "node_size %u, offset %u, len %u\n",
 74		       node->this, node->type, node->height,
 75		       node->tree->node_size, off, len);
 76		return;
 77	}
 78
 79	len = check_and_correct_requested_length(node, off, len);
 80
 81	off += node->page_offset;
 82	pagenum = off >> PAGE_SHIFT;
 83	off &= ~PAGE_MASK; /* compute page offset for the first page */
 84
 85	for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
 86		if (pagenum >= node->tree->pages_per_bnode)
 87			break;
 88		page = node->page[pagenum];
 89		bytes_to_read = min_t(u32, len - bytes_read, PAGE_SIZE - off);
 90
 91		memcpy_from_page(buf + bytes_read, page, off, bytes_to_read);
 92
 93		pagenum++;
 94		off = 0; /* page offset only applies to the first page */
 95	}
 96}
 97
 98u16 hfs_bnode_read_u16(struct hfs_bnode *node, u32 off)
 99{
100	__be16 data;
101	// optimize later...
102	hfs_bnode_read(node, &data, off, 2);
103	return be16_to_cpu(data);
104}
105
106u8 hfs_bnode_read_u8(struct hfs_bnode *node, u32 off)
107{
108	u8 data;
109	// optimize later...
110	hfs_bnode_read(node, &data, off, 1);
111	return data;
112}
113
114void hfs_bnode_read_key(struct hfs_bnode *node, void *key, u32 off)
115{
116	struct hfs_btree *tree;
117	u32 key_len;
118
119	tree = node->tree;
120	if (node->type == HFS_NODE_LEAF ||
121	    tree->attributes & HFS_TREE_VARIDXKEYS)
122		key_len = hfs_bnode_read_u8(node, off) + 1;
123	else
124		key_len = tree->max_key_len + 1;
125
126	if (key_len > sizeof(hfs_btree_key) || key_len < 1) {
127		memset(key, 0, sizeof(hfs_btree_key));
128		pr_err("hfs: Invalid key length: %u\n", key_len);
129		return;
130	}
131
132	hfs_bnode_read(node, key, off, key_len);
133}
134
135void hfs_bnode_write(struct hfs_bnode *node, void *buf, u32 off, u32 len)
136{
137	struct page *page;
138
139	if (!is_bnode_offset_valid(node, off))
140		return;
141
142	if (len == 0) {
143		pr_err("requested zero length: "
144		       "NODE: id %u, type %#x, height %u, "
145		       "node_size %u, offset %u, len %u\n",
146		       node->this, node->type, node->height,
147		       node->tree->node_size, off, len);
148		return;
149	}
150
151	len = check_and_correct_requested_length(node, off, len);
152
153	off += node->page_offset;
154	page = node->page[0];
155
156	memcpy_to_page(page, off, buf, len);
157	set_page_dirty(page);
158}
159
160void hfs_bnode_write_u16(struct hfs_bnode *node, u32 off, u16 data)
161{
162	__be16 v = cpu_to_be16(data);
163	// optimize later...
164	hfs_bnode_write(node, &v, off, 2);
165}
166
167void hfs_bnode_write_u8(struct hfs_bnode *node, u32 off, u8 data)
168{
169	// optimize later...
170	hfs_bnode_write(node, &data, off, 1);
171}
172
173void hfs_bnode_clear(struct hfs_bnode *node, u32 off, u32 len)
174{
175	struct page *page;
176
177	if (!is_bnode_offset_valid(node, off))
178		return;
179
180	if (len == 0) {
181		pr_err("requested zero length: "
182		       "NODE: id %u, type %#x, height %u, "
183		       "node_size %u, offset %u, len %u\n",
184		       node->this, node->type, node->height,
185		       node->tree->node_size, off, len);
186		return;
187	}
188
189	len = check_and_correct_requested_length(node, off, len);
190
191	off += node->page_offset;
192	page = node->page[0];
193
194	memzero_page(page, off, len);
195	set_page_dirty(page);
196}
197
198void hfs_bnode_copy(struct hfs_bnode *dst_node, u32 dst,
199		    struct hfs_bnode *src_node, u32 src, u32 len)
200{
201	struct page *src_page, *dst_page;
202
203	hfs_dbg("dst %u, src %u, len %u\n", dst, src, len);
204	if (!len)
205		return;
206
207	len = check_and_correct_requested_length(src_node, src, len);
208	len = check_and_correct_requested_length(dst_node, dst, len);
209
210	src += src_node->page_offset;
211	dst += dst_node->page_offset;
212	src_page = src_node->page[0];
213	dst_page = dst_node->page[0];
214
215	memcpy_page(dst_page, dst, src_page, src, len);
216	set_page_dirty(dst_page);
217}
218
219void hfs_bnode_move(struct hfs_bnode *node, u32 dst, u32 src, u32 len)
220{
221	struct page *page;
222	void *ptr;
223
224	hfs_dbg("dst %u, src %u, len %u\n", dst, src, len);
225	if (!len)
226		return;
227
228	len = check_and_correct_requested_length(node, src, len);
229	len = check_and_correct_requested_length(node, dst, len);
230
231	src += node->page_offset;
232	dst += node->page_offset;
233	page = node->page[0];
234	ptr = kmap_local_page(page);
235	memmove(ptr + dst, ptr + src, len);
236	kunmap_local(ptr);
237	set_page_dirty(page);
238}
239
240void hfs_bnode_dump(struct hfs_bnode *node)
241{
242	struct hfs_bnode_desc desc;
243	__be32 cnid;
244	int i, off, key_off;
245
246	hfs_dbg("node %d\n", node->this);
247	hfs_bnode_read(node, &desc, 0, sizeof(desc));
248	hfs_dbg("next %d, prev %d, type %d, height %d, num_recs %d\n",
249		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
250		desc.type, desc.height, be16_to_cpu(desc.num_recs));
251
252	off = node->tree->node_size - 2;
253	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
254		key_off = hfs_bnode_read_u16(node, off);
255		hfs_dbg(" key_off %d", key_off);
256		if (i && node->type == HFS_NODE_INDEX) {
257			int tmp;
258
259			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
260				tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
261			else
262				tmp = node->tree->max_key_len + 1;
263			hfs_dbg(" (%d,%d",
264				tmp, hfs_bnode_read_u8(node, key_off));
265			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
266			hfs_dbg(", cnid %d)", be32_to_cpu(cnid));
267		} else if (i && node->type == HFS_NODE_LEAF) {
268			int tmp;
269
270			tmp = hfs_bnode_read_u8(node, key_off);
271			hfs_dbg(" (%d)", tmp);
272		}
273	}
274	hfs_dbg("\n");
275}
276
277void hfs_bnode_unlink(struct hfs_bnode *node)
278{
279	struct hfs_btree *tree;
280	struct hfs_bnode *tmp;
281	__be32 cnid;
282
283	tree = node->tree;
284	if (node->prev) {
285		tmp = hfs_bnode_find(tree, node->prev);
286		if (IS_ERR(tmp))
287			return;
288		tmp->next = node->next;
289		cnid = cpu_to_be32(tmp->next);
290		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
291		hfs_bnode_put(tmp);
292	} else if (node->type == HFS_NODE_LEAF)
293		tree->leaf_head = node->next;
294
295	if (node->next) {
296		tmp = hfs_bnode_find(tree, node->next);
297		if (IS_ERR(tmp))
298			return;
299		tmp->prev = node->prev;
300		cnid = cpu_to_be32(tmp->prev);
301		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
302		hfs_bnode_put(tmp);
303	} else if (node->type == HFS_NODE_LEAF)
304		tree->leaf_tail = node->prev;
305
306	// move down?
307	if (!node->prev && !node->next) {
308		printk(KERN_DEBUG "hfs_btree_del_level\n");
309	}
310	if (!node->parent) {
311		tree->root = 0;
312		tree->depth = 0;
313	}
314	set_bit(HFS_BNODE_DELETED, &node->flags);
315}
316
317static inline int hfs_bnode_hash(u32 num)
318{
319	num = (num >> 16) + num;
320	num += num >> 8;
321	return num & (NODE_HASH_SIZE - 1);
322}
323
324struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
325{
326	struct hfs_bnode *node;
327
328	if (cnid >= tree->node_count) {
329		pr_err("request for non-existent node %d in B*Tree\n", cnid);
330		return NULL;
331	}
332
333	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
334	     node; node = node->next_hash) {
335		if (node->this == cnid) {
336			return node;
337		}
338	}
339	return NULL;
340}
341
342static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
343{
344	struct hfs_bnode *node, *node2;
345	struct address_space *mapping;
346	struct page *page;
347	int size, block, i, hash;
348	loff_t off;
349
350	if (cnid >= tree->node_count) {
351		pr_err("request for non-existent node %d in B*Tree\n", cnid);
352		return NULL;
353	}
354
355	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
356		sizeof(struct page *);
357	node = kzalloc(size, GFP_KERNEL);
358	if (!node)
359		return NULL;
360	node->tree = tree;
361	node->this = cnid;
362	set_bit(HFS_BNODE_NEW, &node->flags);
363	atomic_set(&node->refcnt, 1);
364	hfs_dbg("cnid %d, node %d, refcnt 1\n",
365		node->tree->cnid, node->this);
366	init_waitqueue_head(&node->lock_wq);
367	spin_lock(&tree->hash_lock);
368	node2 = hfs_bnode_findhash(tree, cnid);
369	if (!node2) {
370		hash = hfs_bnode_hash(cnid);
371		node->next_hash = tree->node_hash[hash];
372		tree->node_hash[hash] = node;
373		tree->node_hash_cnt++;
374	} else {
375		hfs_bnode_get(node2);
376		spin_unlock(&tree->hash_lock);
377		kfree(node);
378		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
379		return node2;
380	}
381	spin_unlock(&tree->hash_lock);
382
383	mapping = tree->inode->i_mapping;
384	off = (loff_t)cnid * tree->node_size;
385	block = off >> PAGE_SHIFT;
386	node->page_offset = off & ~PAGE_MASK;
387	for (i = 0; i < tree->pages_per_bnode; i++) {
388		page = read_mapping_page(mapping, block++, NULL);
389		if (IS_ERR(page))
390			goto fail;
391		node->page[i] = page;
392	}
393
394	return node;
395fail:
396	set_bit(HFS_BNODE_ERROR, &node->flags);
397	return node;
398}
399
400void hfs_bnode_unhash(struct hfs_bnode *node)
401{
402	struct hfs_bnode **p;
403
404	hfs_dbg("cnid %d, node %d, refcnt %d\n",
405		node->tree->cnid, node->this, atomic_read(&node->refcnt));
406	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
407	     *p && *p != node; p = &(*p)->next_hash)
408		;
409	BUG_ON(!*p);
410	*p = node->next_hash;
411	node->tree->node_hash_cnt--;
412}
413
414/* Load a particular node out of a tree */
415struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
416{
417	struct hfs_bnode *node;
418	struct hfs_bnode_desc *desc;
419	int i, rec_off, off, next_off;
420	int entry_size, key_size;
421
422	spin_lock(&tree->hash_lock);
423	node = hfs_bnode_findhash(tree, num);
424	if (node) {
425		hfs_bnode_get(node);
426		spin_unlock(&tree->hash_lock);
427		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
428		if (test_bit(HFS_BNODE_ERROR, &node->flags))
429			goto node_error;
430		return node;
431	}
432	spin_unlock(&tree->hash_lock);
433	node = __hfs_bnode_create(tree, num);
434	if (!node)
435		return ERR_PTR(-ENOMEM);
436	if (test_bit(HFS_BNODE_ERROR, &node->flags))
437		goto node_error;
438	if (!test_bit(HFS_BNODE_NEW, &node->flags))
439		return node;
440
441	desc = (struct hfs_bnode_desc *)(kmap_local_page(node->page[0]) +
442					 node->page_offset);
443	node->prev = be32_to_cpu(desc->prev);
444	node->next = be32_to_cpu(desc->next);
445	node->num_recs = be16_to_cpu(desc->num_recs);
446	node->type = desc->type;
447	node->height = desc->height;
448	kunmap_local(desc);
449
450	switch (node->type) {
451	case HFS_NODE_HEADER:
452	case HFS_NODE_MAP:
453		if (node->height != 0)
454			goto node_error;
455		break;
456	case HFS_NODE_LEAF:
457		if (node->height != 1)
458			goto node_error;
459		break;
460	case HFS_NODE_INDEX:
461		if (node->height <= 1 || node->height > tree->depth)
462			goto node_error;
463		break;
464	default:
465		goto node_error;
466	}
467
468	rec_off = tree->node_size - 2;
469	off = hfs_bnode_read_u16(node, rec_off);
470	if (off != sizeof(struct hfs_bnode_desc))
471		goto node_error;
472	for (i = 1; i <= node->num_recs; off = next_off, i++) {
473		rec_off -= 2;
474		next_off = hfs_bnode_read_u16(node, rec_off);
475		if (next_off <= off ||
476		    next_off > tree->node_size ||
477		    next_off & 1)
478			goto node_error;
479		entry_size = next_off - off;
480		if (node->type != HFS_NODE_INDEX &&
481		    node->type != HFS_NODE_LEAF)
482			continue;
483		key_size = hfs_bnode_read_u8(node, off) + 1;
484		if (key_size >= entry_size /*|| key_size & 1*/)
485			goto node_error;
486	}
487	clear_bit(HFS_BNODE_NEW, &node->flags);
488	wake_up(&node->lock_wq);
489	return node;
490
491node_error:
492	set_bit(HFS_BNODE_ERROR, &node->flags);
493	clear_bit(HFS_BNODE_NEW, &node->flags);
494	wake_up(&node->lock_wq);
495	hfs_bnode_put(node);
496	return ERR_PTR(-EIO);
497}
498
499void hfs_bnode_free(struct hfs_bnode *node)
500{
501	int i;
502
503	for (i = 0; i < node->tree->pages_per_bnode; i++)
504		if (node->page[i])
505			put_page(node->page[i]);
506	kfree(node);
507}
508
509struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
510{
511	struct hfs_bnode *node;
512	struct page **pagep;
513	int i;
514
515	spin_lock(&tree->hash_lock);
516	node = hfs_bnode_findhash(tree, num);
517	spin_unlock(&tree->hash_lock);
518	if (node) {
519		pr_crit("new node %u already hashed?\n", num);
520		WARN_ON(1);
521		return node;
522	}
523	node = __hfs_bnode_create(tree, num);
524	if (!node)
525		return ERR_PTR(-ENOMEM);
526	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
527		hfs_bnode_put(node);
528		return ERR_PTR(-EIO);
529	}
530
531	pagep = node->page;
532	memzero_page(*pagep, node->page_offset,
533		     min((int)PAGE_SIZE, (int)tree->node_size));
534	set_page_dirty(*pagep);
535	for (i = 1; i < tree->pages_per_bnode; i++) {
536		memzero_page(*++pagep, 0, PAGE_SIZE);
537		set_page_dirty(*pagep);
538	}
539	clear_bit(HFS_BNODE_NEW, &node->flags);
540	wake_up(&node->lock_wq);
541
542	return node;
543}
544
545void hfs_bnode_get(struct hfs_bnode *node)
546{
547	if (node) {
548		atomic_inc(&node->refcnt);
549		hfs_dbg("cnid %d, node %d, refcnt %d\n",
550			node->tree->cnid, node->this,
551			atomic_read(&node->refcnt));
552	}
553}
554
555/* Dispose of resources used by a node */
556void hfs_bnode_put(struct hfs_bnode *node)
557{
558	if (node) {
559		struct hfs_btree *tree = node->tree;
560		int i;
561
562		hfs_dbg("cnid %d, node %d, refcnt %d\n",
563			node->tree->cnid, node->this,
564			atomic_read(&node->refcnt));
565		BUG_ON(!atomic_read(&node->refcnt));
566		if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
567			return;
568		for (i = 0; i < tree->pages_per_bnode; i++) {
569			if (!node->page[i])
570				continue;
571			mark_page_accessed(node->page[i]);
572		}
573
574		if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
575			hfs_bnode_unhash(node);
576			spin_unlock(&tree->hash_lock);
577			hfs_bnode_clear(node, 0, tree->node_size);
578			hfs_bmap_free(node);
579			hfs_bnode_free(node);
580			return;
581		}
582		spin_unlock(&tree->hash_lock);
583	}
584}