security: tlk_driver: kernel mem type allocation
[linux-3.10.git] / fs / hfsplus / btree.c
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                 pr_err("invalid btree extent records (0 size)\n");
44                 goto free_inode;
45         }
46
47         mapping = tree->inode->i_mapping;
48         page = read_mapping_page(mapping, 0, NULL);
49         if (IS_ERR(page))
50                 goto free_inode;
51
52         /* Load the header */
53         head = (struct hfs_btree_header_rec *)(kmap(page) +
54                 sizeof(struct hfs_bnode_desc));
55         tree->root = be32_to_cpu(head->root);
56         tree->leaf_count = be32_to_cpu(head->leaf_count);
57         tree->leaf_head = be32_to_cpu(head->leaf_head);
58         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
59         tree->node_count = be32_to_cpu(head->node_count);
60         tree->free_nodes = be32_to_cpu(head->free_nodes);
61         tree->attributes = be32_to_cpu(head->attributes);
62         tree->node_size = be16_to_cpu(head->node_size);
63         tree->max_key_len = be16_to_cpu(head->max_key_len);
64         tree->depth = be16_to_cpu(head->depth);
65
66         /* Verify the tree and set the correct compare function */
67         switch (id) {
68         case HFSPLUS_EXT_CNID:
69                 if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
70                         pr_err("invalid extent max_key_len %d\n",
71                                 tree->max_key_len);
72                         goto fail_page;
73                 }
74                 if (tree->attributes & HFS_TREE_VARIDXKEYS) {
75                         pr_err("invalid extent btree flag\n");
76                         goto fail_page;
77                 }
78
79                 tree->keycmp = hfsplus_ext_cmp_key;
80                 break;
81         case HFSPLUS_CAT_CNID:
82                 if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
83                         pr_err("invalid catalog max_key_len %d\n",
84                                 tree->max_key_len);
85                         goto fail_page;
86                 }
87                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
88                         pr_err("invalid catalog btree flag\n");
89                         goto fail_page;
90                 }
91
92                 if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
93                     (head->key_type == HFSPLUS_KEY_BINARY))
94                         tree->keycmp = hfsplus_cat_bin_cmp_key;
95                 else {
96                         tree->keycmp = hfsplus_cat_case_cmp_key;
97                         set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
98                 }
99                 break;
100         case HFSPLUS_ATTR_CNID:
101                 if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
102                         pr_err("invalid attributes max_key_len %d\n",
103                                 tree->max_key_len);
104                         goto fail_page;
105                 }
106                 tree->keycmp = hfsplus_attr_bin_cmp_key;
107                 break;
108         default:
109                 pr_err("unknown B*Tree requested\n");
110                 goto fail_page;
111         }
112
113         if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
114                 pr_err("invalid btree flag\n");
115                 goto fail_page;
116         }
117
118         size = tree->node_size;
119         if (!is_power_of_2(size))
120                 goto fail_page;
121         if (!tree->node_count)
122                 goto fail_page;
123
124         tree->node_size_shift = ffs(size) - 1;
125
126         tree->pages_per_bnode =
127                 (tree->node_size + PAGE_CACHE_SIZE - 1) >>
128                 PAGE_CACHE_SHIFT;
129
130         kunmap(page);
131         page_cache_release(page);
132         return tree;
133
134  fail_page:
135         page_cache_release(page);
136  free_inode:
137         tree->inode->i_mapping->a_ops = &hfsplus_aops;
138         iput(tree->inode);
139  free_tree:
140         kfree(tree);
141         return NULL;
142 }
143
144 /* Release resources used by a btree */
145 void hfs_btree_close(struct hfs_btree *tree)
146 {
147         struct hfs_bnode *node;
148         int i;
149
150         if (!tree)
151                 return;
152
153         for (i = 0; i < NODE_HASH_SIZE; i++) {
154                 while ((node = tree->node_hash[i])) {
155                         tree->node_hash[i] = node->next_hash;
156                         if (atomic_read(&node->refcnt))
157                                 pr_crit("node %d:%d "
158                                                 "still has %d user(s)!\n",
159                                         node->tree->cnid, node->this,
160                                         atomic_read(&node->refcnt));
161                         hfs_bnode_free(node);
162                         tree->node_hash_cnt--;
163                 }
164         }
165         iput(tree->inode);
166         kfree(tree);
167 }
168
169 int hfs_btree_write(struct hfs_btree *tree)
170 {
171         struct hfs_btree_header_rec *head;
172         struct hfs_bnode *node;
173         struct page *page;
174
175         node = hfs_bnode_find(tree, 0);
176         if (IS_ERR(node))
177                 /* panic? */
178                 return -EIO;
179         /* Load the header */
180         page = node->page[0];
181         head = (struct hfs_btree_header_rec *)(kmap(page) +
182                 sizeof(struct hfs_bnode_desc));
183
184         head->root = cpu_to_be32(tree->root);
185         head->leaf_count = cpu_to_be32(tree->leaf_count);
186         head->leaf_head = cpu_to_be32(tree->leaf_head);
187         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
188         head->node_count = cpu_to_be32(tree->node_count);
189         head->free_nodes = cpu_to_be32(tree->free_nodes);
190         head->attributes = cpu_to_be32(tree->attributes);
191         head->depth = cpu_to_be16(tree->depth);
192
193         kunmap(page);
194         set_page_dirty(page);
195         hfs_bnode_put(node);
196         return 0;
197 }
198
199 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
200 {
201         struct hfs_btree *tree = prev->tree;
202         struct hfs_bnode *node;
203         struct hfs_bnode_desc desc;
204         __be32 cnid;
205
206         node = hfs_bnode_create(tree, idx);
207         if (IS_ERR(node))
208                 return node;
209
210         tree->free_nodes--;
211         prev->next = idx;
212         cnid = cpu_to_be32(idx);
213         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
214
215         node->type = HFS_NODE_MAP;
216         node->num_recs = 1;
217         hfs_bnode_clear(node, 0, tree->node_size);
218         desc.next = 0;
219         desc.prev = 0;
220         desc.type = HFS_NODE_MAP;
221         desc.height = 0;
222         desc.num_recs = cpu_to_be16(1);
223         desc.reserved = 0;
224         hfs_bnode_write(node, &desc, 0, sizeof(desc));
225         hfs_bnode_write_u16(node, 14, 0x8000);
226         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
227         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
228
229         return node;
230 }
231
232 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
233 {
234         struct hfs_bnode *node, *next_node;
235         struct page **pagep;
236         u32 nidx, idx;
237         unsigned off;
238         u16 off16;
239         u16 len;
240         u8 *data, byte, m;
241         int i;
242
243         while (!tree->free_nodes) {
244                 struct inode *inode = tree->inode;
245                 struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
246                 u32 count;
247                 int res;
248
249                 res = hfsplus_file_extend(inode);
250                 if (res)
251                         return ERR_PTR(res);
252                 hip->phys_size = inode->i_size =
253                         (loff_t)hip->alloc_blocks <<
254                                 HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
255                 hip->fs_blocks =
256                         hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
257                 inode_set_bytes(inode, inode->i_size);
258                 count = inode->i_size >> tree->node_size_shift;
259                 tree->free_nodes = count - tree->node_count;
260                 tree->node_count = count;
261         }
262
263         nidx = 0;
264         node = hfs_bnode_find(tree, nidx);
265         if (IS_ERR(node))
266                 return node;
267         len = hfs_brec_lenoff(node, 2, &off16);
268         off = off16;
269
270         off += node->page_offset;
271         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
272         data = kmap(*pagep);
273         off &= ~PAGE_CACHE_MASK;
274         idx = 0;
275
276         for (;;) {
277                 while (len) {
278                         byte = data[off];
279                         if (byte != 0xff) {
280                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
281                                         if (!(byte & m)) {
282                                                 idx += i;
283                                                 data[off] |= m;
284                                                 set_page_dirty(*pagep);
285                                                 kunmap(*pagep);
286                                                 tree->free_nodes--;
287                                                 mark_inode_dirty(tree->inode);
288                                                 hfs_bnode_put(node);
289                                                 return hfs_bnode_create(tree,
290                                                         idx);
291                                         }
292                                 }
293                         }
294                         if (++off >= PAGE_CACHE_SIZE) {
295                                 kunmap(*pagep);
296                                 data = kmap(*++pagep);
297                                 off = 0;
298                         }
299                         idx += 8;
300                         len--;
301                 }
302                 kunmap(*pagep);
303                 nidx = node->next;
304                 if (!nidx) {
305                         hfs_dbg(BNODE_MOD, "create new bmap node\n");
306                         next_node = hfs_bmap_new_bmap(node, idx);
307                 } else
308                         next_node = hfs_bnode_find(tree, nidx);
309                 hfs_bnode_put(node);
310                 if (IS_ERR(next_node))
311                         return next_node;
312                 node = next_node;
313
314                 len = hfs_brec_lenoff(node, 0, &off16);
315                 off = off16;
316                 off += node->page_offset;
317                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
318                 data = kmap(*pagep);
319                 off &= ~PAGE_CACHE_MASK;
320         }
321 }
322
323 void hfs_bmap_free(struct hfs_bnode *node)
324 {
325         struct hfs_btree *tree;
326         struct page *page;
327         u16 off, len;
328         u32 nidx;
329         u8 *data, byte, m;
330
331         hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
332         BUG_ON(!node->this);
333         tree = node->tree;
334         nidx = node->this;
335         node = hfs_bnode_find(tree, 0);
336         if (IS_ERR(node))
337                 return;
338         len = hfs_brec_lenoff(node, 2, &off);
339         while (nidx >= len * 8) {
340                 u32 i;
341
342                 nidx -= len * 8;
343                 i = node->next;
344                 hfs_bnode_put(node);
345                 if (!i) {
346                         /* panic */;
347                         pr_crit("unable to free bnode %u. "
348                                         "bmap not found!\n",
349                                 node->this);
350                         return;
351                 }
352                 node = hfs_bnode_find(tree, i);
353                 if (IS_ERR(node))
354                         return;
355                 if (node->type != HFS_NODE_MAP) {
356                         /* panic */;
357                         pr_crit("invalid bmap found! "
358                                         "(%u,%d)\n",
359                                 node->this, node->type);
360                         hfs_bnode_put(node);
361                         return;
362                 }
363                 len = hfs_brec_lenoff(node, 0, &off);
364         }
365         off += node->page_offset + nidx / 8;
366         page = node->page[off >> PAGE_CACHE_SHIFT];
367         data = kmap(page);
368         off &= ~PAGE_CACHE_MASK;
369         m = 1 << (~nidx & 7);
370         byte = data[off];
371         if (!(byte & m)) {
372                 pr_crit("trying to free free bnode "
373                                 "%u(%d)\n",
374                         node->this, node->type);
375                 kunmap(page);
376                 hfs_bnode_put(node);
377                 return;
378         }
379         data[off] = byte & ~m;
380         set_page_dirty(page);
381         kunmap(page);
382         hfs_bnode_put(node);
383         tree->free_nodes++;
384         mark_inode_dirty(tree->inode);
385 }