xref: /openbmc/linux/fs/hfs/btree.c (revision b6dcefde)
1 /*
2  *  linux/fs/hfs/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/pagemap.h>
12 #include <linux/log2.h>
13 
14 #include "btree.h"
15 
16 /* Get a reference to a B*Tree and do some initial checks */
17 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
18 {
19 	struct hfs_btree *tree;
20 	struct hfs_btree_header_rec *head;
21 	struct address_space *mapping;
22 	struct page *page;
23 	unsigned int size;
24 
25 	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
26 	if (!tree)
27 		return NULL;
28 
29 	init_MUTEX(&tree->tree_lock);
30 	spin_lock_init(&tree->hash_lock);
31 	/* Set the correct compare function */
32 	tree->sb = sb;
33 	tree->cnid = id;
34 	tree->keycmp = keycmp;
35 
36 	tree->inode = iget_locked(sb, id);
37 	if (!tree->inode)
38 		goto free_tree;
39 	BUG_ON(!(tree->inode->i_state & I_NEW));
40 	{
41 	struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
42 	HFS_I(tree->inode)->flags = 0;
43 	mutex_init(&HFS_I(tree->inode)->extents_lock);
44 	switch (id) {
45 	case HFS_EXT_CNID:
46 		hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
47 				    mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
48 		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
49 		break;
50 	case HFS_CAT_CNID:
51 		hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
52 				    mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
53 		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
54 		break;
55 	default:
56 		BUG();
57 	}
58 	}
59 	unlock_new_inode(tree->inode);
60 
61 	if (!HFS_I(tree->inode)->first_blocks) {
62 		printk(KERN_ERR "hfs: invalid btree extent records (0 size).\n");
63 		goto free_inode;
64 	}
65 
66 	mapping = tree->inode->i_mapping;
67 	page = read_mapping_page(mapping, 0, NULL);
68 	if (IS_ERR(page))
69 		goto free_inode;
70 
71 	/* Load the header */
72 	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
73 	tree->root = be32_to_cpu(head->root);
74 	tree->leaf_count = be32_to_cpu(head->leaf_count);
75 	tree->leaf_head = be32_to_cpu(head->leaf_head);
76 	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
77 	tree->node_count = be32_to_cpu(head->node_count);
78 	tree->free_nodes = be32_to_cpu(head->free_nodes);
79 	tree->attributes = be32_to_cpu(head->attributes);
80 	tree->node_size = be16_to_cpu(head->node_size);
81 	tree->max_key_len = be16_to_cpu(head->max_key_len);
82 	tree->depth = be16_to_cpu(head->depth);
83 
84 	size = tree->node_size;
85 	if (!is_power_of_2(size))
86 		goto fail_page;
87 	if (!tree->node_count)
88 		goto fail_page;
89 	switch (id) {
90 	case HFS_EXT_CNID:
91 		if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
92 			printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
93 				tree->max_key_len);
94 			goto fail_page;
95 		}
96 		break;
97 	case HFS_CAT_CNID:
98 		if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
99 			printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
100 				tree->max_key_len);
101 			goto fail_page;
102 		}
103 		break;
104 	default:
105 		BUG();
106 	}
107 
108 	tree->node_size_shift = ffs(size) - 1;
109 	tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
110 
111 	kunmap(page);
112 	page_cache_release(page);
113 	return tree;
114 
115 fail_page:
116 	page_cache_release(page);
117 free_inode:
118 	tree->inode->i_mapping->a_ops = &hfs_aops;
119 	iput(tree->inode);
120 free_tree:
121 	kfree(tree);
122 	return NULL;
123 }
124 
125 /* Release resources used by a btree */
126 void hfs_btree_close(struct hfs_btree *tree)
127 {
128 	struct hfs_bnode *node;
129 	int i;
130 
131 	if (!tree)
132 		return;
133 
134 	for (i = 0; i < NODE_HASH_SIZE; i++) {
135 		while ((node = tree->node_hash[i])) {
136 			tree->node_hash[i] = node->next_hash;
137 			if (atomic_read(&node->refcnt))
138 				printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
139 					node->tree->cnid, node->this, atomic_read(&node->refcnt));
140 			hfs_bnode_free(node);
141 			tree->node_hash_cnt--;
142 		}
143 	}
144 	iput(tree->inode);
145 	kfree(tree);
146 }
147 
148 void hfs_btree_write(struct hfs_btree *tree)
149 {
150 	struct hfs_btree_header_rec *head;
151 	struct hfs_bnode *node;
152 	struct page *page;
153 
154 	node = hfs_bnode_find(tree, 0);
155 	if (IS_ERR(node))
156 		/* panic? */
157 		return;
158 	/* Load the header */
159 	page = node->page[0];
160 	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
161 
162 	head->root = cpu_to_be32(tree->root);
163 	head->leaf_count = cpu_to_be32(tree->leaf_count);
164 	head->leaf_head = cpu_to_be32(tree->leaf_head);
165 	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
166 	head->node_count = cpu_to_be32(tree->node_count);
167 	head->free_nodes = cpu_to_be32(tree->free_nodes);
168 	head->attributes = cpu_to_be32(tree->attributes);
169 	head->depth = cpu_to_be16(tree->depth);
170 
171 	kunmap(page);
172 	set_page_dirty(page);
173 	hfs_bnode_put(node);
174 }
175 
176 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
177 {
178 	struct hfs_btree *tree = prev->tree;
179 	struct hfs_bnode *node;
180 	struct hfs_bnode_desc desc;
181 	__be32 cnid;
182 
183 	node = hfs_bnode_create(tree, idx);
184 	if (IS_ERR(node))
185 		return node;
186 
187 	if (!tree->free_nodes)
188 		panic("FIXME!!!");
189 	tree->free_nodes--;
190 	prev->next = idx;
191 	cnid = cpu_to_be32(idx);
192 	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
193 
194 	node->type = HFS_NODE_MAP;
195 	node->num_recs = 1;
196 	hfs_bnode_clear(node, 0, tree->node_size);
197 	desc.next = 0;
198 	desc.prev = 0;
199 	desc.type = HFS_NODE_MAP;
200 	desc.height = 0;
201 	desc.num_recs = cpu_to_be16(1);
202 	desc.reserved = 0;
203 	hfs_bnode_write(node, &desc, 0, sizeof(desc));
204 	hfs_bnode_write_u16(node, 14, 0x8000);
205 	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
206 	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
207 
208 	return node;
209 }
210 
211 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
212 {
213 	struct hfs_bnode *node, *next_node;
214 	struct page **pagep;
215 	u32 nidx, idx;
216 	unsigned off;
217 	u16 off16;
218 	u16 len;
219 	u8 *data, byte, m;
220 	int i;
221 
222 	while (!tree->free_nodes) {
223 		struct inode *inode = tree->inode;
224 		u32 count;
225 		int res;
226 
227 		res = hfs_extend_file(inode);
228 		if (res)
229 			return ERR_PTR(res);
230 		HFS_I(inode)->phys_size = inode->i_size =
231 				(loff_t)HFS_I(inode)->alloc_blocks *
232 				HFS_SB(tree->sb)->alloc_blksz;
233 		HFS_I(inode)->fs_blocks = inode->i_size >>
234 					  tree->sb->s_blocksize_bits;
235 		inode_set_bytes(inode, inode->i_size);
236 		count = inode->i_size >> tree->node_size_shift;
237 		tree->free_nodes = count - tree->node_count;
238 		tree->node_count = count;
239 	}
240 
241 	nidx = 0;
242 	node = hfs_bnode_find(tree, nidx);
243 	if (IS_ERR(node))
244 		return node;
245 	len = hfs_brec_lenoff(node, 2, &off16);
246 	off = off16;
247 
248 	off += node->page_offset;
249 	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
250 	data = kmap(*pagep);
251 	off &= ~PAGE_CACHE_MASK;
252 	idx = 0;
253 
254 	for (;;) {
255 		while (len) {
256 			byte = data[off];
257 			if (byte != 0xff) {
258 				for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
259 					if (!(byte & m)) {
260 						idx += i;
261 						data[off] |= m;
262 						set_page_dirty(*pagep);
263 						kunmap(*pagep);
264 						tree->free_nodes--;
265 						mark_inode_dirty(tree->inode);
266 						hfs_bnode_put(node);
267 						return hfs_bnode_create(tree, idx);
268 					}
269 				}
270 			}
271 			if (++off >= PAGE_CACHE_SIZE) {
272 				kunmap(*pagep);
273 				data = kmap(*++pagep);
274 				off = 0;
275 			}
276 			idx += 8;
277 			len--;
278 		}
279 		kunmap(*pagep);
280 		nidx = node->next;
281 		if (!nidx) {
282 			printk(KERN_DEBUG "hfs: create new bmap node...\n");
283 			next_node = hfs_bmap_new_bmap(node, idx);
284 		} else
285 			next_node = hfs_bnode_find(tree, nidx);
286 		hfs_bnode_put(node);
287 		if (IS_ERR(next_node))
288 			return next_node;
289 		node = next_node;
290 
291 		len = hfs_brec_lenoff(node, 0, &off16);
292 		off = off16;
293 		off += node->page_offset;
294 		pagep = node->page + (off >> PAGE_CACHE_SHIFT);
295 		data = kmap(*pagep);
296 		off &= ~PAGE_CACHE_MASK;
297 	}
298 }
299 
300 void hfs_bmap_free(struct hfs_bnode *node)
301 {
302 	struct hfs_btree *tree;
303 	struct page *page;
304 	u16 off, len;
305 	u32 nidx;
306 	u8 *data, byte, m;
307 
308 	dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
309 	tree = node->tree;
310 	nidx = node->this;
311 	node = hfs_bnode_find(tree, 0);
312 	if (IS_ERR(node))
313 		return;
314 	len = hfs_brec_lenoff(node, 2, &off);
315 	while (nidx >= len * 8) {
316 		u32 i;
317 
318 		nidx -= len * 8;
319 		i = node->next;
320 		hfs_bnode_put(node);
321 		if (!i) {
322 			/* panic */;
323 			printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
324 			return;
325 		}
326 		node = hfs_bnode_find(tree, i);
327 		if (IS_ERR(node))
328 			return;
329 		if (node->type != HFS_NODE_MAP) {
330 			/* panic */;
331 			printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
332 			hfs_bnode_put(node);
333 			return;
334 		}
335 		len = hfs_brec_lenoff(node, 0, &off);
336 	}
337 	off += node->page_offset + nidx / 8;
338 	page = node->page[off >> PAGE_CACHE_SHIFT];
339 	data = kmap(page);
340 	off &= ~PAGE_CACHE_MASK;
341 	m = 1 << (~nidx & 7);
342 	byte = data[off];
343 	if (!(byte & m)) {
344 		printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
345 		kunmap(page);
346 		hfs_bnode_put(node);
347 		return;
348 	}
349 	data[off] = byte & ~m;
350 	set_page_dirty(page);
351 	kunmap(page);
352 	hfs_bnode_put(node);
353 	tree->free_nodes++;
354 	mark_inode_dirty(tree->inode);
355 }
356