xref: /openbmc/linux/fs/hfsplus/btree.c (revision 840ef8b7cc584a23c4f9d05352f4dbaf8e56e5ab)
1 /*
2  *  linux/fs/hfsplus/btree.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handle opening/closing btree
9  */
10 
11 #include <linux/slab.h>
12 #include <linux/pagemap.h>
13 #include <linux/log2.h>
14 
15 #include "hfsplus_fs.h"
16 #include "hfsplus_raw.h"
17 
18 
19 /* Get a reference to a B*Tree and do some initial checks */
20 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
21 {
22 	struct hfs_btree *tree;
23 	struct hfs_btree_header_rec *head;
24 	struct address_space *mapping;
25 	struct inode *inode;
26 	struct page *page;
27 	unsigned int size;
28 
29 	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
30 	if (!tree)
31 		return NULL;
32 
33 	mutex_init(&tree->tree_lock);
34 	spin_lock_init(&tree->hash_lock);
35 	tree->sb = sb;
36 	tree->cnid = id;
37 	inode = hfsplus_iget(sb, id);
38 	if (IS_ERR(inode))
39 		goto free_tree;
40 	tree->inode = inode;
41 
42 	if (!HFSPLUS_I(tree->inode)->first_blocks) {
43 		printk(KERN_ERR
44 		       "hfs: invalid btree extent records (0 size).\n");
45 		goto free_inode;
46 	}
47 
48 	mapping = tree->inode->i_mapping;
49 	page = read_mapping_page(mapping, 0, NULL);
50 	if (IS_ERR(page))
51 		goto free_inode;
52 
53 	/* Load the header */
54 	head = (struct hfs_btree_header_rec *)(kmap(page) +
55 		sizeof(struct hfs_bnode_desc));
56 	tree->root = be32_to_cpu(head->root);
57 	tree->leaf_count = be32_to_cpu(head->leaf_count);
58 	tree->leaf_head = be32_to_cpu(head->leaf_head);
59 	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
60 	tree->node_count = be32_to_cpu(head->node_count);
61 	tree->free_nodes = be32_to_cpu(head->free_nodes);
62 	tree->attributes = be32_to_cpu(head->attributes);
63 	tree->node_size = be16_to_cpu(head->node_size);
64 	tree->max_key_len = be16_to_cpu(head->max_key_len);
65 	tree->depth = be16_to_cpu(head->depth);
66 
67 	/* Verify the tree and set the correct compare function */
68 	switch (id) {
69 	case HFSPLUS_EXT_CNID:
70 		if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
71 			printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
72 				tree->max_key_len);
73 			goto fail_page;
74 		}
75 		if (tree->attributes & HFS_TREE_VARIDXKEYS) {
76 			printk(KERN_ERR "hfs: invalid extent btree flag\n");
77 			goto fail_page;
78 		}
79 
80 		tree->keycmp = hfsplus_ext_cmp_key;
81 		break;
82 	case HFSPLUS_CAT_CNID:
83 		if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
84 			printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
85 				tree->max_key_len);
86 			goto fail_page;
87 		}
88 		if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
89 			printk(KERN_ERR "hfs: invalid catalog btree flag\n");
90 			goto fail_page;
91 		}
92 
93 		if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
94 		    (head->key_type == HFSPLUS_KEY_BINARY))
95 			tree->keycmp = hfsplus_cat_bin_cmp_key;
96 		else {
97 			tree->keycmp = hfsplus_cat_case_cmp_key;
98 			set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
99 		}
100 		break;
101 	case HFSPLUS_ATTR_CNID:
102 		if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
103 			printk(KERN_ERR "hfs: invalid attributes max_key_len %d\n",
104 				tree->max_key_len);
105 			goto fail_page;
106 		}
107 		tree->keycmp = hfsplus_attr_bin_cmp_key;
108 		break;
109 	default:
110 		printk(KERN_ERR "hfs: unknown B*Tree requested\n");
111 		goto fail_page;
112 	}
113 
114 	if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
115 		printk(KERN_ERR "hfs: invalid btree flag\n");
116 		goto fail_page;
117 	}
118 
119 	size = tree->node_size;
120 	if (!is_power_of_2(size))
121 		goto fail_page;
122 	if (!tree->node_count)
123 		goto fail_page;
124 
125 	tree->node_size_shift = ffs(size) - 1;
126 
127 	tree->pages_per_bnode =
128 		(tree->node_size + PAGE_CACHE_SIZE - 1) >>
129 		PAGE_CACHE_SHIFT;
130 
131 	kunmap(page);
132 	page_cache_release(page);
133 	return tree;
134 
135  fail_page:
136 	page_cache_release(page);
137  free_inode:
138 	tree->inode->i_mapping->a_ops = &hfsplus_aops;
139 	iput(tree->inode);
140  free_tree:
141 	kfree(tree);
142 	return NULL;
143 }
144 
145 /* Release resources used by a btree */
146 void hfs_btree_close(struct hfs_btree *tree)
147 {
148 	struct hfs_bnode *node;
149 	int i;
150 
151 	if (!tree)
152 		return;
153 
154 	for (i = 0; i < NODE_HASH_SIZE; i++) {
155 		while ((node = tree->node_hash[i])) {
156 			tree->node_hash[i] = node->next_hash;
157 			if (atomic_read(&node->refcnt))
158 				printk(KERN_CRIT "hfs: node %d:%d "
159 						"still has %d user(s)!\n",
160 					node->tree->cnid, node->this,
161 					atomic_read(&node->refcnt));
162 			hfs_bnode_free(node);
163 			tree->node_hash_cnt--;
164 		}
165 	}
166 	iput(tree->inode);
167 	kfree(tree);
168 }
169 
170 int hfs_btree_write(struct hfs_btree *tree)
171 {
172 	struct hfs_btree_header_rec *head;
173 	struct hfs_bnode *node;
174 	struct page *page;
175 
176 	node = hfs_bnode_find(tree, 0);
177 	if (IS_ERR(node))
178 		/* panic? */
179 		return -EIO;
180 	/* Load the header */
181 	page = node->page[0];
182 	head = (struct hfs_btree_header_rec *)(kmap(page) +
183 		sizeof(struct hfs_bnode_desc));
184 
185 	head->root = cpu_to_be32(tree->root);
186 	head->leaf_count = cpu_to_be32(tree->leaf_count);
187 	head->leaf_head = cpu_to_be32(tree->leaf_head);
188 	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
189 	head->node_count = cpu_to_be32(tree->node_count);
190 	head->free_nodes = cpu_to_be32(tree->free_nodes);
191 	head->attributes = cpu_to_be32(tree->attributes);
192 	head->depth = cpu_to_be16(tree->depth);
193 
194 	kunmap(page);
195 	set_page_dirty(page);
196 	hfs_bnode_put(node);
197 	return 0;
198 }
199 
200 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
201 {
202 	struct hfs_btree *tree = prev->tree;
203 	struct hfs_bnode *node;
204 	struct hfs_bnode_desc desc;
205 	__be32 cnid;
206 
207 	node = hfs_bnode_create(tree, idx);
208 	if (IS_ERR(node))
209 		return node;
210 
211 	tree->free_nodes--;
212 	prev->next = idx;
213 	cnid = cpu_to_be32(idx);
214 	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
215 
216 	node->type = HFS_NODE_MAP;
217 	node->num_recs = 1;
218 	hfs_bnode_clear(node, 0, tree->node_size);
219 	desc.next = 0;
220 	desc.prev = 0;
221 	desc.type = HFS_NODE_MAP;
222 	desc.height = 0;
223 	desc.num_recs = cpu_to_be16(1);
224 	desc.reserved = 0;
225 	hfs_bnode_write(node, &desc, 0, sizeof(desc));
226 	hfs_bnode_write_u16(node, 14, 0x8000);
227 	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
228 	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
229 
230 	return node;
231 }
232 
233 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
234 {
235 	struct hfs_bnode *node, *next_node;
236 	struct page **pagep;
237 	u32 nidx, idx;
238 	unsigned off;
239 	u16 off16;
240 	u16 len;
241 	u8 *data, byte, m;
242 	int i;
243 
244 	while (!tree->free_nodes) {
245 		struct inode *inode = tree->inode;
246 		struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
247 		u32 count;
248 		int res;
249 
250 		res = hfsplus_file_extend(inode);
251 		if (res)
252 			return ERR_PTR(res);
253 		hip->phys_size = inode->i_size =
254 			(loff_t)hip->alloc_blocks <<
255 				HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
256 		hip->fs_blocks =
257 			hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
258 		inode_set_bytes(inode, inode->i_size);
259 		count = inode->i_size >> tree->node_size_shift;
260 		tree->free_nodes = count - tree->node_count;
261 		tree->node_count = count;
262 	}
263 
264 	nidx = 0;
265 	node = hfs_bnode_find(tree, nidx);
266 	if (IS_ERR(node))
267 		return node;
268 	len = hfs_brec_lenoff(node, 2, &off16);
269 	off = off16;
270 
271 	off += node->page_offset;
272 	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
273 	data = kmap(*pagep);
274 	off &= ~PAGE_CACHE_MASK;
275 	idx = 0;
276 
277 	for (;;) {
278 		while (len) {
279 			byte = data[off];
280 			if (byte != 0xff) {
281 				for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
282 					if (!(byte & m)) {
283 						idx += i;
284 						data[off] |= m;
285 						set_page_dirty(*pagep);
286 						kunmap(*pagep);
287 						tree->free_nodes--;
288 						mark_inode_dirty(tree->inode);
289 						hfs_bnode_put(node);
290 						return hfs_bnode_create(tree,
291 							idx);
292 					}
293 				}
294 			}
295 			if (++off >= PAGE_CACHE_SIZE) {
296 				kunmap(*pagep);
297 				data = kmap(*++pagep);
298 				off = 0;
299 			}
300 			idx += 8;
301 			len--;
302 		}
303 		kunmap(*pagep);
304 		nidx = node->next;
305 		if (!nidx) {
306 			dprint(DBG_BNODE_MOD, "hfs: create new bmap node.\n");
307 			next_node = hfs_bmap_new_bmap(node, idx);
308 		} else
309 			next_node = hfs_bnode_find(tree, nidx);
310 		hfs_bnode_put(node);
311 		if (IS_ERR(next_node))
312 			return next_node;
313 		node = next_node;
314 
315 		len = hfs_brec_lenoff(node, 0, &off16);
316 		off = off16;
317 		off += node->page_offset;
318 		pagep = node->page + (off >> PAGE_CACHE_SHIFT);
319 		data = kmap(*pagep);
320 		off &= ~PAGE_CACHE_MASK;
321 	}
322 }
323 
324 void hfs_bmap_free(struct hfs_bnode *node)
325 {
326 	struct hfs_btree *tree;
327 	struct page *page;
328 	u16 off, len;
329 	u32 nidx;
330 	u8 *data, byte, m;
331 
332 	dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
333 	BUG_ON(!node->this);
334 	tree = node->tree;
335 	nidx = node->this;
336 	node = hfs_bnode_find(tree, 0);
337 	if (IS_ERR(node))
338 		return;
339 	len = hfs_brec_lenoff(node, 2, &off);
340 	while (nidx >= len * 8) {
341 		u32 i;
342 
343 		nidx -= len * 8;
344 		i = node->next;
345 		hfs_bnode_put(node);
346 		if (!i) {
347 			/* panic */;
348 			printk(KERN_CRIT "hfs: unable to free bnode %u. "
349 					"bmap not found!\n",
350 				node->this);
351 			return;
352 		}
353 		node = hfs_bnode_find(tree, i);
354 		if (IS_ERR(node))
355 			return;
356 		if (node->type != HFS_NODE_MAP) {
357 			/* panic */;
358 			printk(KERN_CRIT "hfs: invalid bmap found! "
359 					"(%u,%d)\n",
360 				node->this, node->type);
361 			hfs_bnode_put(node);
362 			return;
363 		}
364 		len = hfs_brec_lenoff(node, 0, &off);
365 	}
366 	off += node->page_offset + nidx / 8;
367 	page = node->page[off >> PAGE_CACHE_SHIFT];
368 	data = kmap(page);
369 	off &= ~PAGE_CACHE_MASK;
370 	m = 1 << (~nidx & 7);
371 	byte = data[off];
372 	if (!(byte & m)) {
373 		printk(KERN_CRIT "hfs: trying to free free bnode "
374 				"%u(%d)\n",
375 			node->this, node->type);
376 		kunmap(page);
377 		hfs_bnode_put(node);
378 		return;
379 	}
380 	data[off] = byte & ~m;
381 	set_page_dirty(page);
382 	kunmap(page);
383 	hfs_bnode_put(node);
384 	tree->free_nodes++;
385 	mark_inode_dirty(tree->inode);
386 }
387