xref: /openbmc/linux/fs/hfs/btree.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 
13 #include "btree.h"
14 
15 /* Get a reference to a B*Tree and do some initial checks */
16 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
17 {
18 	struct hfs_btree *tree;
19 	struct hfs_btree_header_rec *head;
20 	struct address_space *mapping;
21 	struct page *page;
22 	unsigned int size;
23 
24 	tree = kmalloc(sizeof(*tree), GFP_KERNEL);
25 	if (!tree)
26 		return NULL;
27 	memset(tree, 0, sizeof(*tree));
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 	if (!(tree->inode->i_state & I_NEW))
40 		BUG();
41 	{
42 	struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
43 	HFS_I(tree->inode)->flags = 0;
44 	init_MUTEX(&HFS_I(tree->inode)->extents_lock);
45 	switch (id) {
46 	case HFS_EXT_CNID:
47 		hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
48 				    mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
49 		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
50 		break;
51 	case HFS_CAT_CNID:
52 		hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
53 				    mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
54 		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
55 		break;
56 	default:
57 		BUG();
58 	}
59 	}
60 	unlock_new_inode(tree->inode);
61 
62 	mapping = tree->inode->i_mapping;
63 	page = read_cache_page(mapping, 0, (filler_t *)mapping->a_ops->readpage, NULL);
64 	if (IS_ERR(page))
65 		goto free_tree;
66 
67 	/* Load the header */
68 	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
69 	tree->root = be32_to_cpu(head->root);
70 	tree->leaf_count = be32_to_cpu(head->leaf_count);
71 	tree->leaf_head = be32_to_cpu(head->leaf_head);
72 	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
73 	tree->node_count = be32_to_cpu(head->node_count);
74 	tree->free_nodes = be32_to_cpu(head->free_nodes);
75 	tree->attributes = be32_to_cpu(head->attributes);
76 	tree->node_size = be16_to_cpu(head->node_size);
77 	tree->max_key_len = be16_to_cpu(head->max_key_len);
78 	tree->depth = be16_to_cpu(head->depth);
79 
80 	size = tree->node_size;
81 	if (!size || size & (size - 1))
82 		goto fail_page;
83 	if (!tree->node_count)
84 		goto fail_page;
85 	tree->node_size_shift = ffs(size) - 1;
86 	tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
87 
88 	kunmap(page);
89 	page_cache_release(page);
90 	return tree;
91 
92  fail_page:
93 	tree->inode->i_mapping->a_ops = &hfs_aops;
94 	page_cache_release(page);
95  free_tree:
96 	iput(tree->inode);
97 	kfree(tree);
98 	return NULL;
99 }
100 
101 /* Release resources used by a btree */
102 void hfs_btree_close(struct hfs_btree *tree)
103 {
104 	struct hfs_bnode *node;
105 	int i;
106 
107 	if (!tree)
108 		return;
109 
110 	for (i = 0; i < NODE_HASH_SIZE; i++) {
111 		while ((node = tree->node_hash[i])) {
112 			tree->node_hash[i] = node->next_hash;
113 			if (atomic_read(&node->refcnt))
114 				printk("HFS: node %d:%d still has %d user(s)!\n",
115 					node->tree->cnid, node->this, atomic_read(&node->refcnt));
116 			hfs_bnode_free(node);
117 			tree->node_hash_cnt--;
118 		}
119 	}
120 	iput(tree->inode);
121 	kfree(tree);
122 }
123 
124 void hfs_btree_write(struct hfs_btree *tree)
125 {
126 	struct hfs_btree_header_rec *head;
127 	struct hfs_bnode *node;
128 	struct page *page;
129 
130 	node = hfs_bnode_find(tree, 0);
131 	if (IS_ERR(node))
132 		/* panic? */
133 		return;
134 	/* Load the header */
135 	page = node->page[0];
136 	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
137 
138 	head->root = cpu_to_be32(tree->root);
139 	head->leaf_count = cpu_to_be32(tree->leaf_count);
140 	head->leaf_head = cpu_to_be32(tree->leaf_head);
141 	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
142 	head->node_count = cpu_to_be32(tree->node_count);
143 	head->free_nodes = cpu_to_be32(tree->free_nodes);
144 	head->attributes = cpu_to_be32(tree->attributes);
145 	head->depth = cpu_to_be16(tree->depth);
146 
147 	kunmap(page);
148 	set_page_dirty(page);
149 	hfs_bnode_put(node);
150 }
151 
152 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
153 {
154 	struct hfs_btree *tree = prev->tree;
155 	struct hfs_bnode *node;
156 	struct hfs_bnode_desc desc;
157 	__be32 cnid;
158 
159 	node = hfs_bnode_create(tree, idx);
160 	if (IS_ERR(node))
161 		return node;
162 
163 	if (!tree->free_nodes)
164 		panic("FIXME!!!");
165 	tree->free_nodes--;
166 	prev->next = idx;
167 	cnid = cpu_to_be32(idx);
168 	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
169 
170 	node->type = HFS_NODE_MAP;
171 	node->num_recs = 1;
172 	hfs_bnode_clear(node, 0, tree->node_size);
173 	desc.next = 0;
174 	desc.prev = 0;
175 	desc.type = HFS_NODE_MAP;
176 	desc.height = 0;
177 	desc.num_recs = cpu_to_be16(1);
178 	desc.reserved = 0;
179 	hfs_bnode_write(node, &desc, 0, sizeof(desc));
180 	hfs_bnode_write_u16(node, 14, 0x8000);
181 	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
182 	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
183 
184 	return node;
185 }
186 
187 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
188 {
189 	struct hfs_bnode *node, *next_node;
190 	struct page **pagep;
191 	u32 nidx, idx;
192 	u16 off, len;
193 	u8 *data, byte, m;
194 	int i;
195 
196 	while (!tree->free_nodes) {
197 		struct inode *inode = tree->inode;
198 		u32 count;
199 		int res;
200 
201 		res = hfs_extend_file(inode);
202 		if (res)
203 			return ERR_PTR(res);
204 		HFS_I(inode)->phys_size = inode->i_size =
205 				(loff_t)HFS_I(inode)->alloc_blocks *
206 				HFS_SB(tree->sb)->alloc_blksz;
207 		HFS_I(inode)->fs_blocks = inode->i_size >>
208 					  tree->sb->s_blocksize_bits;
209 		inode_set_bytes(inode, inode->i_size);
210 		count = inode->i_size >> tree->node_size_shift;
211 		tree->free_nodes = count - tree->node_count;
212 		tree->node_count = count;
213 	}
214 
215 	nidx = 0;
216 	node = hfs_bnode_find(tree, nidx);
217 	if (IS_ERR(node))
218 		return node;
219 	len = hfs_brec_lenoff(node, 2, &off);
220 
221 	off += node->page_offset;
222 	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
223 	data = kmap(*pagep);
224 	off &= ~PAGE_CACHE_MASK;
225 	idx = 0;
226 
227 	for (;;) {
228 		while (len) {
229 			byte = data[off];
230 			if (byte != 0xff) {
231 				for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
232 					if (!(byte & m)) {
233 						idx += i;
234 						data[off] |= m;
235 						set_page_dirty(*pagep);
236 						kunmap(*pagep);
237 						tree->free_nodes--;
238 						mark_inode_dirty(tree->inode);
239 						hfs_bnode_put(node);
240 						return hfs_bnode_create(tree, idx);
241 					}
242 				}
243 			}
244 			if (++off >= PAGE_CACHE_SIZE) {
245 				kunmap(*pagep);
246 				data = kmap(*++pagep);
247 				off = 0;
248 			}
249 			idx += 8;
250 			len--;
251 		}
252 		kunmap(*pagep);
253 		nidx = node->next;
254 		if (!nidx) {
255 			printk("create new bmap node...\n");
256 			next_node = hfs_bmap_new_bmap(node, idx);
257 		} else
258 			next_node = hfs_bnode_find(tree, nidx);
259 		hfs_bnode_put(node);
260 		if (IS_ERR(next_node))
261 			return next_node;
262 		node = next_node;
263 
264 		len = hfs_brec_lenoff(node, 0, &off);
265 		off += node->page_offset;
266 		pagep = node->page + (off >> PAGE_CACHE_SHIFT);
267 		data = kmap(*pagep);
268 		off &= ~PAGE_CACHE_MASK;
269 	}
270 }
271 
272 void hfs_bmap_free(struct hfs_bnode *node)
273 {
274 	struct hfs_btree *tree;
275 	struct page *page;
276 	u16 off, len;
277 	u32 nidx;
278 	u8 *data, byte, m;
279 
280 	dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
281 	tree = node->tree;
282 	nidx = node->this;
283 	node = hfs_bnode_find(tree, 0);
284 	if (IS_ERR(node))
285 		return;
286 	len = hfs_brec_lenoff(node, 2, &off);
287 	while (nidx >= len * 8) {
288 		u32 i;
289 
290 		nidx -= len * 8;
291 		i = node->next;
292 		hfs_bnode_put(node);
293 		if (!i) {
294 			/* panic */;
295 			printk("HFS: unable to free bnode %u. bmap not found!\n", node->this);
296 			return;
297 		}
298 		node = hfs_bnode_find(tree, i);
299 		if (IS_ERR(node))
300 			return;
301 		if (node->type != HFS_NODE_MAP) {
302 			/* panic */;
303 			printk("HFS: invalid bmap found! (%u,%d)\n", node->this, node->type);
304 			hfs_bnode_put(node);
305 			return;
306 		}
307 		len = hfs_brec_lenoff(node, 0, &off);
308 	}
309 	off += node->page_offset + nidx / 8;
310 	page = node->page[off >> PAGE_CACHE_SHIFT];
311 	data = kmap(page);
312 	off &= ~PAGE_CACHE_MASK;
313 	m = 1 << (~nidx & 7);
314 	byte = data[off];
315 	if (!(byte & m)) {
316 		printk("HFS: trying to free free bnode %u(%d)\n", node->this, node->type);
317 		kunmap(page);
318 		hfs_bnode_put(node);
319 		return;
320 	}
321 	data[off] = byte & ~m;
322 	set_page_dirty(page);
323 	kunmap(page);
324 	hfs_bnode_put(node);
325 	tree->free_nodes++;
326 	mark_inode_dirty(tree->inode);
327 }
328