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 init_MUTEX(&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 mapping = tree->inode->i_mapping;
43 page = read_mapping_page(mapping, 0, NULL);
44 if (IS_ERR(page))
45 goto free_tree;
46
47 /* Load the header */
48 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
49 tree->root = be32_to_cpu(head->root);
50 tree->leaf_count = be32_to_cpu(head->leaf_count);
51 tree->leaf_head = be32_to_cpu(head->leaf_head);
52 tree->leaf_tail = be32_to_cpu(head->leaf_tail);
53 tree->node_count = be32_to_cpu(head->node_count);
54 tree->free_nodes = be32_to_cpu(head->free_nodes);
55 tree->attributes = be32_to_cpu(head->attributes);
56 tree->node_size = be16_to_cpu(head->node_size);
57 tree->max_key_len = be16_to_cpu(head->max_key_len);
58 tree->depth = be16_to_cpu(head->depth);
59
60 /* Set the correct compare function */
61 if (id == HFSPLUS_EXT_CNID) {
62 tree->keycmp = hfsplus_ext_cmp_key;
63 } else if (id == HFSPLUS_CAT_CNID) {
64 if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) &&
65 (head->key_type == HFSPLUS_KEY_BINARY))
66 tree->keycmp = hfsplus_cat_bin_cmp_key;
67 else {
68 tree->keycmp = hfsplus_cat_case_cmp_key;
69 HFSPLUS_SB(sb).flags |= HFSPLUS_SB_CASEFOLD;
70 }
71 } else {
72 printk(KERN_ERR "hfs: unknown B*Tree requested\n");
73 goto fail_page;
74 }
75
76 size = tree->node_size;
77 if (!is_power_of_2(size))
78 goto fail_page;
79 if (!tree->node_count)
80 goto fail_page;
81 tree->node_size_shift = ffs(size) - 1;
82
83 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
84
85 kunmap(page);
86 page_cache_release(page);
87 return tree;
88
89 fail_page:
90 tree->inode->i_mapping->a_ops = &hfsplus_aops;
91 page_cache_release(page);
92 free_tree:
93 iput(tree->inode);
94 kfree(tree);
95 return NULL;
96 }
97
98 /* Release resources used by a btree */
99 void hfs_btree_close(struct hfs_btree *tree)
100 {
101 struct hfs_bnode *node;
102 int i;
103
104 if (!tree)
105 return;
106
107 for (i = 0; i < NODE_HASH_SIZE; i++) {
108 while ((node = tree->node_hash[i])) {
109 tree->node_hash[i] = node->next_hash;
110 if (atomic_read(&node->refcnt))
111 printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n",
112 node->tree->cnid, node->this, atomic_read(&node->refcnt));
113 hfs_bnode_free(node);
114 tree->node_hash_cnt--;
115 }
116 }
117 iput(tree->inode);
118 kfree(tree);
119 }
120
121 void hfs_btree_write(struct hfs_btree *tree)
122 {
123 struct hfs_btree_header_rec *head;
124 struct hfs_bnode *node;
125 struct page *page;
126
127 node = hfs_bnode_find(tree, 0);
128 if (IS_ERR(node))
129 /* panic? */
130 return;
131 /* Load the header */
132 page = node->page[0];
133 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
134
135 head->root = cpu_to_be32(tree->root);
136 head->leaf_count = cpu_to_be32(tree->leaf_count);
137 head->leaf_head = cpu_to_be32(tree->leaf_head);
138 head->leaf_tail = cpu_to_be32(tree->leaf_tail);
139 head->node_count = cpu_to_be32(tree->node_count);
140 head->free_nodes = cpu_to_be32(tree->free_nodes);
141 head->attributes = cpu_to_be32(tree->attributes);
142 head->depth = cpu_to_be16(tree->depth);
143
144 kunmap(page);
145 set_page_dirty(page);
146 hfs_bnode_put(node);
147 }
148
149 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
150 {
151 struct hfs_btree *tree = prev->tree;
152 struct hfs_bnode *node;
153 struct hfs_bnode_desc desc;
154 __be32 cnid;
155
156 node = hfs_bnode_create(tree, idx);
157 if (IS_ERR(node))
158 return node;
159
160 tree->free_nodes--;
161 prev->next = idx;
162 cnid = cpu_to_be32(idx);
163 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
164
165 node->type = HFS_NODE_MAP;
166 node->num_recs = 1;
167 hfs_bnode_clear(node, 0, tree->node_size);
168 desc.next = 0;
169 desc.prev = 0;
170 desc.type = HFS_NODE_MAP;
171 desc.height = 0;
172 desc.num_recs = cpu_to_be16(1);
173 desc.reserved = 0;
174 hfs_bnode_write(node, &desc, 0, sizeof(desc));
175 hfs_bnode_write_u16(node, 14, 0x8000);
176 hfs_bnode_write_u16(node, tree->node_size - 2, 14);
177 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
178
179 return node;
180 }
181
182 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
183 {
184 struct hfs_bnode *node, *next_node;
185 struct page **pagep;
186 u32 nidx, idx;
187 unsigned off;
188 u16 off16;
189 u16 len;
190 u8 *data, byte, m;
191 int i;
192
193 while (!tree->free_nodes) {
194 struct inode *inode = tree->inode;
195 u32 count;
196 int res;
197
198 res = hfsplus_file_extend(inode);
199 if (res)
200 return ERR_PTR(res);
201 HFSPLUS_I(inode).phys_size = inode->i_size =
202 (loff_t)HFSPLUS_I(inode).alloc_blocks <<
203 HFSPLUS_SB(tree->sb).alloc_blksz_shift;
204 HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks <<
205 HFSPLUS_SB(tree->sb).fs_shift;
206 inode_set_bytes(inode, inode->i_size);
207 count = inode->i_size >> tree->node_size_shift;
208 tree->free_nodes = count - tree->node_count;
209 tree->node_count = count;
210 }
211
212 nidx = 0;
213 node = hfs_bnode_find(tree, nidx);
214 if (IS_ERR(node))
215 return node;
216 len = hfs_brec_lenoff(node, 2, &off16);
217 off = off16;
218
219 off += node->page_offset;
220 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
221 data = kmap(*pagep);
222 off &= ~PAGE_CACHE_MASK;
223 idx = 0;
224
225 for (;;) {
226 while (len) {
227 byte = data[off];
228 if (byte != 0xff) {
229 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
230 if (!(byte & m)) {
231 idx += i;
232 data[off] |= m;
233 set_page_dirty(*pagep);
234 kunmap(*pagep);
235 tree->free_nodes--;
236 mark_inode_dirty(tree->inode);
237 hfs_bnode_put(node);
238 return hfs_bnode_create(tree, idx);
239 }
240 }
241 }
242 if (++off >= PAGE_CACHE_SIZE) {
243 kunmap(*pagep);
244 data = kmap(*++pagep);
245 off = 0;
246 }
247 idx += 8;
248 len--;
249 }
250 kunmap(*pagep);
251 nidx = node->next;
252 if (!nidx) {
253 printk(KERN_DEBUG "hfs: create new bmap node...\n");
254 next_node = hfs_bmap_new_bmap(node, idx);
255 } else
256 next_node = hfs_bnode_find(tree, nidx);
257 hfs_bnode_put(node);
258 if (IS_ERR(next_node))
259 return next_node;
260 node = next_node;
261
262 len = hfs_brec_lenoff(node, 0, &off16);
263 off = off16;
264 off += node->page_offset;
265 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
266 data = kmap(*pagep);
267 off &= ~PAGE_CACHE_MASK;
268 }
269 }
270
271 void hfs_bmap_free(struct hfs_bnode *node)
272 {
273 struct hfs_btree *tree;
274 struct page *page;
275 u16 off, len;
276 u32 nidx;
277 u8 *data, byte, m;
278
279 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
280 BUG_ON(!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(KERN_CRIT "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(KERN_CRIT "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(KERN_CRIT "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
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