1/*
2 *  linux/fs/hfsplus/bnode.c
3 *
4 * Copyright (C) 2001
5 * Brad Boyer (flar@allandria.com)
6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
7 *
8 * Handle basic btree node operations
9 */
10
11#include <linux/string.h>
12#include <linux/slab.h>
13#include <linux/pagemap.h>
14#include <linux/fs.h>
15#include <linux/swap.h>
16
17#include "hfsplus_fs.h"
18#include "hfsplus_raw.h"
19
20/* Copy a specified range of bytes from the raw data of a node */
21void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
22{
23	struct page **pagep;
24	int l;
25
26	off += node->page_offset;
27	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
28	off &= ~PAGE_CACHE_MASK;
29
30	l = min(len, (int)PAGE_CACHE_SIZE - off);
31	memcpy(buf, kmap(*pagep) + off, l);
32	kunmap(*pagep);
33
34	while ((len -= l) != 0) {
35		buf += l;
36		l = min(len, (int)PAGE_CACHE_SIZE);
37		memcpy(buf, kmap(*++pagep), l);
38		kunmap(*pagep);
39	}
40}
41
42u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
43{
44	__be16 data;
45	// optimize later...
46	hfs_bnode_read(node, &data, off, 2);
47	return be16_to_cpu(data);
48}
49
50u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
51{
52	u8 data;
53	// optimize later...
54	hfs_bnode_read(node, &data, off, 1);
55	return data;
56}
57
58void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
59{
60	struct hfs_btree *tree;
61	int key_len;
62
63	tree = node->tree;
64	if (node->type == HFS_NODE_LEAF ||
65	    tree->attributes & HFS_TREE_VARIDXKEYS)
66		key_len = hfs_bnode_read_u16(node, off) + 2;
67	else
68		key_len = tree->max_key_len + 2;
69
70	hfs_bnode_read(node, key, off, key_len);
71}
72
73void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
74{
75	struct page **pagep;
76	int l;
77
78	off += node->page_offset;
79	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
80	off &= ~PAGE_CACHE_MASK;
81
82	l = min(len, (int)PAGE_CACHE_SIZE - off);
83	memcpy(kmap(*pagep) + off, buf, l);
84	set_page_dirty(*pagep);
85	kunmap(*pagep);
86
87	while ((len -= l) != 0) {
88		buf += l;
89		l = min(len, (int)PAGE_CACHE_SIZE);
90		memcpy(kmap(*++pagep), buf, l);
91		set_page_dirty(*pagep);
92		kunmap(*pagep);
93	}
94}
95
96void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
97{
98	__be16 v = cpu_to_be16(data);
99	// optimize later...
100	hfs_bnode_write(node, &v, off, 2);
101}
102
103void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
104{
105	struct page **pagep;
106	int l;
107
108	off += node->page_offset;
109	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
110	off &= ~PAGE_CACHE_MASK;
111
112	l = min(len, (int)PAGE_CACHE_SIZE - off);
113	memset(kmap(*pagep) + off, 0, l);
114	set_page_dirty(*pagep);
115	kunmap(*pagep);
116
117	while ((len -= l) != 0) {
118		l = min(len, (int)PAGE_CACHE_SIZE);
119		memset(kmap(*++pagep), 0, l);
120		set_page_dirty(*pagep);
121		kunmap(*pagep);
122	}
123}
124
125void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
126		    struct hfs_bnode *src_node, int src, int len)
127{
128	struct hfs_btree *tree;
129	struct page **src_page, **dst_page;
130	int l;
131
132	dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
133	if (!len)
134		return;
135	tree = src_node->tree;
136	src += src_node->page_offset;
137	dst += dst_node->page_offset;
138	src_page = src_node->page + (src >> PAGE_CACHE_SHIFT);
139	src &= ~PAGE_CACHE_MASK;
140	dst_page = dst_node->page + (dst >> PAGE_CACHE_SHIFT);
141	dst &= ~PAGE_CACHE_MASK;
142
143	if (src == dst) {
144		l = min(len, (int)PAGE_CACHE_SIZE - src);
145		memcpy(kmap(*dst_page) + src, kmap(*src_page) + src, l);
146		kunmap(*src_page);
147		set_page_dirty(*dst_page);
148		kunmap(*dst_page);
149
150		while ((len -= l) != 0) {
151			l = min(len, (int)PAGE_CACHE_SIZE);
152			memcpy(kmap(*++dst_page), kmap(*++src_page), l);
153			kunmap(*src_page);
154			set_page_dirty(*dst_page);
155			kunmap(*dst_page);
156		}
157	} else {
158		void *src_ptr, *dst_ptr;
159
160		do {
161			src_ptr = kmap(*src_page) + src;
162			dst_ptr = kmap(*dst_page) + dst;
163			if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
164				l = PAGE_CACHE_SIZE - src;
165				src = 0;
166				dst += l;
167			} else {
168				l = PAGE_CACHE_SIZE - dst;
169				src += l;
170				dst = 0;
171			}
172			l = min(len, l);
173			memcpy(dst_ptr, src_ptr, l);
174			kunmap(*src_page);
175			set_page_dirty(*dst_page);
176			kunmap(*dst_page);
177			if (!dst)
178				dst_page++;
179			else
180				src_page++;
181		} while ((len -= l));
182	}
183}
184
185void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
186{
187	struct page **src_page, **dst_page;
188	int l;
189
190	dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
191	if (!len)
192		return;
193	src += node->page_offset;
194	dst += node->page_offset;
195	if (dst > src) {
196		src += len - 1;
197		src_page = node->page + (src >> PAGE_CACHE_SHIFT);
198		src = (src & ~PAGE_CACHE_MASK) + 1;
199		dst += len - 1;
200		dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
201		dst = (dst & ~PAGE_CACHE_MASK) + 1;
202
203		if (src == dst) {
204			while (src < len) {
205				memmove(kmap(*dst_page), kmap(*src_page), src);
206				kunmap(*src_page);
207				set_page_dirty(*dst_page);
208				kunmap(*dst_page);
209				len -= src;
210				src = PAGE_CACHE_SIZE;
211				src_page--;
212				dst_page--;
213			}
214			src -= len;
215			memmove(kmap(*dst_page) + src, kmap(*src_page) + src, len);
216			kunmap(*src_page);
217			set_page_dirty(*dst_page);
218			kunmap(*dst_page);
219		} else {
220			void *src_ptr, *dst_ptr;
221
222			do {
223				src_ptr = kmap(*src_page) + src;
224				dst_ptr = kmap(*dst_page) + dst;
225				if (src < dst) {
226					l = src;
227					src = PAGE_CACHE_SIZE;
228					dst -= l;
229				} else {
230					l = dst;
231					src -= l;
232					dst = PAGE_CACHE_SIZE;
233				}
234				l = min(len, l);
235				memmove(dst_ptr - l, src_ptr - l, l);
236				kunmap(*src_page);
237				set_page_dirty(*dst_page);
238				kunmap(*dst_page);
239				if (dst == PAGE_CACHE_SIZE)
240					dst_page--;
241				else
242					src_page--;
243			} while ((len -= l));
244		}
245	} else {
246		src_page = node->page + (src >> PAGE_CACHE_SHIFT);
247		src &= ~PAGE_CACHE_MASK;
248		dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
249		dst &= ~PAGE_CACHE_MASK;
250
251		if (src == dst) {
252			l = min(len, (int)PAGE_CACHE_SIZE - src);
253			memmove(kmap(*dst_page) + src, kmap(*src_page) + src, l);
254			kunmap(*src_page);
255			set_page_dirty(*dst_page);
256			kunmap(*dst_page);
257
258			while ((len -= l) != 0) {
259				l = min(len, (int)PAGE_CACHE_SIZE);
260				memmove(kmap(*++dst_page), kmap(*++src_page), l);
261				kunmap(*src_page);
262				set_page_dirty(*dst_page);
263				kunmap(*dst_page);
264			}
265		} else {
266			void *src_ptr, *dst_ptr;
267
268			do {
269				src_ptr = kmap(*src_page) + src;
270				dst_ptr = kmap(*dst_page) + dst;
271				if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
272					l = PAGE_CACHE_SIZE - src;
273					src = 0;
274					dst += l;
275				} else {
276					l = PAGE_CACHE_SIZE - dst;
277					src += l;
278					dst = 0;
279				}
280				l = min(len, l);
281				memmove(dst_ptr, src_ptr, l);
282				kunmap(*src_page);
283				set_page_dirty(*dst_page);
284				kunmap(*dst_page);
285				if (!dst)
286					dst_page++;
287				else
288					src_page++;
289			} while ((len -= l));
290		}
291	}
292}
293
294void hfs_bnode_dump(struct hfs_bnode *node)
295{
296	struct hfs_bnode_desc desc;
297	__be32 cnid;
298	int i, off, key_off;
299
300	dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
301	hfs_bnode_read(node, &desc, 0, sizeof(desc));
302	dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
303		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
304		desc.type, desc.height, be16_to_cpu(desc.num_recs));
305
306	off = node->tree->node_size - 2;
307	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
308		key_off = hfs_bnode_read_u16(node, off);
309		dprint(DBG_BNODE_MOD, " %d", key_off);
310		if (i && node->type == HFS_NODE_INDEX) {
311			int tmp;
312
313			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
314				tmp = hfs_bnode_read_u16(node, key_off) + 2;
315			else
316				tmp = node->tree->max_key_len + 2;
317			dprint(DBG_BNODE_MOD, " (%d", tmp);
318			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
319			dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
320		} else if (i && node->type == HFS_NODE_LEAF) {
321			int tmp;
322
323			tmp = hfs_bnode_read_u16(node, key_off);
324			dprint(DBG_BNODE_MOD, " (%d)", tmp);
325		}
326	}
327	dprint(DBG_BNODE_MOD, "\n");
328}
329
330void hfs_bnode_unlink(struct hfs_bnode *node)
331{
332	struct hfs_btree *tree;
333	struct hfs_bnode *tmp;
334	__be32 cnid;
335
336	tree = node->tree;
337	if (node->prev) {
338		tmp = hfs_bnode_find(tree, node->prev);
339		if (IS_ERR(tmp))
340			return;
341		tmp->next = node->next;
342		cnid = cpu_to_be32(tmp->next);
343		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
344		hfs_bnode_put(tmp);
345	} else if (node->type == HFS_NODE_LEAF)
346		tree->leaf_head = node->next;
347
348	if (node->next) {
349		tmp = hfs_bnode_find(tree, node->next);
350		if (IS_ERR(tmp))
351			return;
352		tmp->prev = node->prev;
353		cnid = cpu_to_be32(tmp->prev);
354		hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
355		hfs_bnode_put(tmp);
356	} else if (node->type == HFS_NODE_LEAF)
357		tree->leaf_tail = node->prev;
358
359	// move down?
360	if (!node->prev && !node->next) {
361		printk(KERN_DEBUG "hfs_btree_del_level\n");
362	}
363	if (!node->parent) {
364		tree->root = 0;
365		tree->depth = 0;
366	}
367	set_bit(HFS_BNODE_DELETED, &node->flags);
368}
369
370static inline int hfs_bnode_hash(u32 num)
371{
372	num = (num >> 16) + num;
373	num += num >> 8;
374	return num & (NODE_HASH_SIZE - 1);
375}
376
377struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
378{
379	struct hfs_bnode *node;
380
381	if (cnid >= tree->node_count) {
382		printk(KERN_ERR "hfs: request for non-existent node %d in B*Tree\n", cnid);
383		return NULL;
384	}
385
386	for (node = tree->node_hash[hfs_bnode_hash(cnid)];
387	     node; node = node->next_hash) {
388		if (node->this == cnid) {
389			return node;
390		}
391	}
392	return NULL;
393}
394
395static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
396{
397	struct super_block *sb;
398	struct hfs_bnode *node, *node2;
399	struct address_space *mapping;
400	struct page *page;
401	int size, block, i, hash;
402	loff_t off;
403
404	if (cnid >= tree->node_count) {
405		printk(KERN_ERR "hfs: request for non-existent node %d in B*Tree\n", cnid);
406		return NULL;
407	}
408
409	sb = tree->inode->i_sb;
410	size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
411		sizeof(struct page *);
412	node = kzalloc(size, GFP_KERNEL);
413	if (!node)
414		return NULL;
415	node->tree = tree;
416	node->this = cnid;
417	set_bit(HFS_BNODE_NEW, &node->flags);
418	atomic_set(&node->refcnt, 1);
419	dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
420	       node->tree->cnid, node->this);
421	init_waitqueue_head(&node->lock_wq);
422	spin_lock(&tree->hash_lock);
423	node2 = hfs_bnode_findhash(tree, cnid);
424	if (!node2) {
425		hash = hfs_bnode_hash(cnid);
426		node->next_hash = tree->node_hash[hash];
427		tree->node_hash[hash] = node;
428		tree->node_hash_cnt++;
429	} else {
430		spin_unlock(&tree->hash_lock);
431		kfree(node);
432		wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
433		return node2;
434	}
435	spin_unlock(&tree->hash_lock);
436
437	mapping = tree->inode->i_mapping;
438	off = (loff_t)cnid << tree->node_size_shift;
439	block = off >> PAGE_CACHE_SHIFT;
440	node->page_offset = off & ~PAGE_CACHE_MASK;
441	for (i = 0; i < tree->pages_per_bnode; block++, i++) {
442		page = read_mapping_page(mapping, block, NULL);
443		if (IS_ERR(page))
444			goto fail;
445		if (PageError(page)) {
446			page_cache_release(page);
447			goto fail;
448		}
449		page_cache_release(page);
450		node->page[i] = page;
451	}
452
453	return node;
454fail:
455	set_bit(HFS_BNODE_ERROR, &node->flags);
456	return node;
457}
458
459void hfs_bnode_unhash(struct hfs_bnode *node)
460{
461	struct hfs_bnode **p;
462
463	dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
464		node->tree->cnid, node->this, atomic_read(&node->refcnt));
465	for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
466	     *p && *p != node; p = &(*p)->next_hash)
467		;
468	BUG_ON(!*p);
469	*p = node->next_hash;
470	node->tree->node_hash_cnt--;
471}
472
473/* Load a particular node out of a tree */
474struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
475{
476	struct hfs_bnode *node;
477	struct hfs_bnode_desc *desc;
478	int i, rec_off, off, next_off;
479	int entry_size, key_size;
480
481	spin_lock(&tree->hash_lock);
482	node = hfs_bnode_findhash(tree, num);
483	if (node) {
484		hfs_bnode_get(node);
485		spin_unlock(&tree->hash_lock);
486		wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
487		if (test_bit(HFS_BNODE_ERROR, &node->flags))
488			goto node_error;
489		return node;
490	}
491	spin_unlock(&tree->hash_lock);
492	node = __hfs_bnode_create(tree, num);
493	if (!node)
494		return ERR_PTR(-ENOMEM);
495	if (test_bit(HFS_BNODE_ERROR, &node->flags))
496		goto node_error;
497	if (!test_bit(HFS_BNODE_NEW, &node->flags))
498		return node;
499
500	desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
501	node->prev = be32_to_cpu(desc->prev);
502	node->next = be32_to_cpu(desc->next);
503	node->num_recs = be16_to_cpu(desc->num_recs);
504	node->type = desc->type;
505	node->height = desc->height;
506	kunmap(node->page[0]);
507
508	switch (node->type) {
509	case HFS_NODE_HEADER:
510	case HFS_NODE_MAP:
511		if (node->height != 0)
512			goto node_error;
513		break;
514	case HFS_NODE_LEAF:
515		if (node->height != 1)
516			goto node_error;
517		break;
518	case HFS_NODE_INDEX:
519		if (node->height <= 1 || node->height > tree->depth)
520			goto node_error;
521		break;
522	default:
523		goto node_error;
524	}
525
526	rec_off = tree->node_size - 2;
527	off = hfs_bnode_read_u16(node, rec_off);
528	if (off != sizeof(struct hfs_bnode_desc))
529		goto node_error;
530	for (i = 1; i <= node->num_recs; off = next_off, i++) {
531		rec_off -= 2;
532		next_off = hfs_bnode_read_u16(node, rec_off);
533		if (next_off <= off ||
534		    next_off > tree->node_size ||
535		    next_off & 1)
536			goto node_error;
537		entry_size = next_off - off;
538		if (node->type != HFS_NODE_INDEX &&
539		    node->type != HFS_NODE_LEAF)
540			continue;
541		key_size = hfs_bnode_read_u16(node, off) + 2;
542		if (key_size >= entry_size || key_size & 1)
543			goto node_error;
544	}
545	clear_bit(HFS_BNODE_NEW, &node->flags);
546	wake_up(&node->lock_wq);
547	return node;
548
549node_error:
550	set_bit(HFS_BNODE_ERROR, &node->flags);
551	clear_bit(HFS_BNODE_NEW, &node->flags);
552	wake_up(&node->lock_wq);
553	hfs_bnode_put(node);
554	return ERR_PTR(-EIO);
555}
556
557void hfs_bnode_free(struct hfs_bnode *node)
558{
559	//int i;
560
561	//for (i = 0; i < node->tree->pages_per_bnode; i++)
562	//	if (node->page[i])
563	//		page_cache_release(node->page[i]);
564	kfree(node);
565}
566
567struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
568{
569	struct hfs_bnode *node;
570	struct page **pagep;
571	int i;
572
573	spin_lock(&tree->hash_lock);
574	node = hfs_bnode_findhash(tree, num);
575	spin_unlock(&tree->hash_lock);
576	if (node) {
577		printk(KERN_CRIT "new node %u already hashed?\n", num);
578		WARN_ON(1);
579		return node;
580	}
581	node = __hfs_bnode_create(tree, num);
582	if (!node)
583		return ERR_PTR(-ENOMEM);
584	if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
585		hfs_bnode_put(node);
586		return ERR_PTR(-EIO);
587	}
588
589	pagep = node->page;
590	memset(kmap(*pagep) + node->page_offset, 0,
591	       min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
592	set_page_dirty(*pagep);
593	kunmap(*pagep);
594	for (i = 1; i < tree->pages_per_bnode; i++) {
595		memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
596		set_page_dirty(*pagep);
597		kunmap(*pagep);
598	}
599	clear_bit(HFS_BNODE_NEW, &node->flags);
600	wake_up(&node->lock_wq);
601
602	return node;
603}
604
605void hfs_bnode_get(struct hfs_bnode *node)
606{
607	if (node) {
608		atomic_inc(&node->refcnt);
609		dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
610		       node->tree->cnid, node->this, atomic_read(&node->refcnt));
611	}
612}
613
614/* Dispose of resources used by a node */
615void hfs_bnode_put(struct hfs_bnode *node)
616{
617	if (node) {
618		struct hfs_btree *tree = node->tree;
619		int i;
620
621		dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
622		       node->tree->cnid, node->this, atomic_read(&node->refcnt));
623		BUG_ON(!atomic_read(&node->refcnt));
624		if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
625			return;
626		for (i = 0; i < tree->pages_per_bnode; i++) {
627			if (!node->page[i])
628				continue;
629			mark_page_accessed(node->page[i]);
630		}
631
632		if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
633			hfs_bnode_unhash(node);
634			spin_unlock(&tree->hash_lock);
635			hfs_bmap_free(node);
636			hfs_bnode_free(node);
637			return;
638		}
639		spin_unlock(&tree->hash_lock);
640	}
641}
642