hfs: fix hfs_find_init() sb->ext_tree NULL ptr oops
[linux-2.6.git] / fs / hfs / btree.c
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/slab.h>
13 #include <linux/log2.h>
14
15 #include "btree.h"
16
17 /* Get a reference to a B*Tree and do some initial checks */
18 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
19 {
20         struct hfs_btree *tree;
21         struct hfs_btree_header_rec *head;
22         struct address_space *mapping;
23         struct page *page;
24         unsigned int size;
25
26         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
27         if (!tree)
28                 return NULL;
29
30         mutex_init(&tree->tree_lock);
31         spin_lock_init(&tree->hash_lock);
32         /* Set the correct compare function */
33         tree->sb = sb;
34         tree->cnid = id;
35         tree->keycmp = keycmp;
36
37         tree->inode = iget_locked(sb, id);
38         if (!tree->inode)
39                 goto free_tree;
40         BUG_ON(!(tree->inode->i_state & I_NEW));
41         {
42         struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
43         HFS_I(tree->inode)->flags = 0;
44         mutex_init(&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                 if (HFS_I(tree->inode)->alloc_blocks >
50                                         HFS_I(tree->inode)->first_blocks) {
51                         printk(KERN_ERR "hfs: invalid btree extent records\n");
52                         unlock_new_inode(tree->inode);
53                         goto free_inode;
54                 }
55
56                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
57                 break;
58         case HFS_CAT_CNID:
59                 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
60                                     mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
61
62                 if (!HFS_I(tree->inode)->first_blocks) {
63                         printk(KERN_ERR "hfs: invalid btree extent records "
64                                                                 "(0 size).\n");
65                         unlock_new_inode(tree->inode);
66                         goto free_inode;
67                 }
68
69                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
70                 break;
71         default:
72                 BUG();
73         }
74         }
75         unlock_new_inode(tree->inode);
76
77         mapping = tree->inode->i_mapping;
78         page = read_mapping_page(mapping, 0, NULL);
79         if (IS_ERR(page))
80                 goto free_inode;
81
82         /* Load the header */
83         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
84         tree->root = be32_to_cpu(head->root);
85         tree->leaf_count = be32_to_cpu(head->leaf_count);
86         tree->leaf_head = be32_to_cpu(head->leaf_head);
87         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
88         tree->node_count = be32_to_cpu(head->node_count);
89         tree->free_nodes = be32_to_cpu(head->free_nodes);
90         tree->attributes = be32_to_cpu(head->attributes);
91         tree->node_size = be16_to_cpu(head->node_size);
92         tree->max_key_len = be16_to_cpu(head->max_key_len);
93         tree->depth = be16_to_cpu(head->depth);
94
95         size = tree->node_size;
96         if (!is_power_of_2(size))
97                 goto fail_page;
98         if (!tree->node_count)
99                 goto fail_page;
100         switch (id) {
101         case HFS_EXT_CNID:
102                 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
103                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
104                                 tree->max_key_len);
105                         goto fail_page;
106                 }
107                 break;
108         case HFS_CAT_CNID:
109                 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
110                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
111                                 tree->max_key_len);
112                         goto fail_page;
113                 }
114                 break;
115         default:
116                 BUG();
117         }
118
119         tree->node_size_shift = ffs(size) - 1;
120         tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
121
122         kunmap(page);
123         page_cache_release(page);
124         return tree;
125
126 fail_page:
127         page_cache_release(page);
128 free_inode:
129         tree->inode->i_mapping->a_ops = &hfs_aops;
130         iput(tree->inode);
131 free_tree:
132         kfree(tree);
133         return NULL;
134 }
135
136 /* Release resources used by a btree */
137 void hfs_btree_close(struct hfs_btree *tree)
138 {
139         struct hfs_bnode *node;
140         int i;
141
142         if (!tree)
143                 return;
144
145         for (i = 0; i < NODE_HASH_SIZE; i++) {
146                 while ((node = tree->node_hash[i])) {
147                         tree->node_hash[i] = node->next_hash;
148                         if (atomic_read(&node->refcnt))
149                                 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
150                                         node->tree->cnid, node->this, atomic_read(&node->refcnt));
151                         hfs_bnode_free(node);
152                         tree->node_hash_cnt--;
153                 }
154         }
155         iput(tree->inode);
156         kfree(tree);
157 }
158
159 void hfs_btree_write(struct hfs_btree *tree)
160 {
161         struct hfs_btree_header_rec *head;
162         struct hfs_bnode *node;
163         struct page *page;
164
165         node = hfs_bnode_find(tree, 0);
166         if (IS_ERR(node))
167                 /* panic? */
168                 return;
169         /* Load the header */
170         page = node->page[0];
171         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
172
173         head->root = cpu_to_be32(tree->root);
174         head->leaf_count = cpu_to_be32(tree->leaf_count);
175         head->leaf_head = cpu_to_be32(tree->leaf_head);
176         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
177         head->node_count = cpu_to_be32(tree->node_count);
178         head->free_nodes = cpu_to_be32(tree->free_nodes);
179         head->attributes = cpu_to_be32(tree->attributes);
180         head->depth = cpu_to_be16(tree->depth);
181
182         kunmap(page);
183         set_page_dirty(page);
184         hfs_bnode_put(node);
185 }
186
187 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
188 {
189         struct hfs_btree *tree = prev->tree;
190         struct hfs_bnode *node;
191         struct hfs_bnode_desc desc;
192         __be32 cnid;
193
194         node = hfs_bnode_create(tree, idx);
195         if (IS_ERR(node))
196                 return node;
197
198         if (!tree->free_nodes)
199                 panic("FIXME!!!");
200         tree->free_nodes--;
201         prev->next = idx;
202         cnid = cpu_to_be32(idx);
203         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
204
205         node->type = HFS_NODE_MAP;
206         node->num_recs = 1;
207         hfs_bnode_clear(node, 0, tree->node_size);
208         desc.next = 0;
209         desc.prev = 0;
210         desc.type = HFS_NODE_MAP;
211         desc.height = 0;
212         desc.num_recs = cpu_to_be16(1);
213         desc.reserved = 0;
214         hfs_bnode_write(node, &desc, 0, sizeof(desc));
215         hfs_bnode_write_u16(node, 14, 0x8000);
216         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
217         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
218
219         return node;
220 }
221
222 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
223 {
224         struct hfs_bnode *node, *next_node;
225         struct page **pagep;
226         u32 nidx, idx;
227         unsigned off;
228         u16 off16;
229         u16 len;
230         u8 *data, byte, m;
231         int i;
232
233         while (!tree->free_nodes) {
234                 struct inode *inode = tree->inode;
235                 u32 count;
236                 int res;
237
238                 res = hfs_extend_file(inode);
239                 if (res)
240                         return ERR_PTR(res);
241                 HFS_I(inode)->phys_size = inode->i_size =
242                                 (loff_t)HFS_I(inode)->alloc_blocks *
243                                 HFS_SB(tree->sb)->alloc_blksz;
244                 HFS_I(inode)->fs_blocks = inode->i_size >>
245                                           tree->sb->s_blocksize_bits;
246                 inode_set_bytes(inode, inode->i_size);
247                 count = inode->i_size >> tree->node_size_shift;
248                 tree->free_nodes = count - tree->node_count;
249                 tree->node_count = count;
250         }
251
252         nidx = 0;
253         node = hfs_bnode_find(tree, nidx);
254         if (IS_ERR(node))
255                 return node;
256         len = hfs_brec_lenoff(node, 2, &off16);
257         off = off16;
258
259         off += node->page_offset;
260         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
261         data = kmap(*pagep);
262         off &= ~PAGE_CACHE_MASK;
263         idx = 0;
264
265         for (;;) {
266                 while (len) {
267                         byte = data[off];
268                         if (byte != 0xff) {
269                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
270                                         if (!(byte & m)) {
271                                                 idx += i;
272                                                 data[off] |= m;
273                                                 set_page_dirty(*pagep);
274                                                 kunmap(*pagep);
275                                                 tree->free_nodes--;
276                                                 mark_inode_dirty(tree->inode);
277                                                 hfs_bnode_put(node);
278                                                 return hfs_bnode_create(tree, idx);
279                                         }
280                                 }
281                         }
282                         if (++off >= PAGE_CACHE_SIZE) {
283                                 kunmap(*pagep);
284                                 data = kmap(*++pagep);
285                                 off = 0;
286                         }
287                         idx += 8;
288                         len--;
289                 }
290                 kunmap(*pagep);
291                 nidx = node->next;
292                 if (!nidx) {
293                         printk(KERN_DEBUG "hfs: create new bmap node...\n");
294                         next_node = hfs_bmap_new_bmap(node, idx);
295                 } else
296                         next_node = hfs_bnode_find(tree, nidx);
297                 hfs_bnode_put(node);
298                 if (IS_ERR(next_node))
299                         return next_node;
300                 node = next_node;
301
302                 len = hfs_brec_lenoff(node, 0, &off16);
303                 off = off16;
304                 off += node->page_offset;
305                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
306                 data = kmap(*pagep);
307                 off &= ~PAGE_CACHE_MASK;
308         }
309 }
310
311 void hfs_bmap_free(struct hfs_bnode *node)
312 {
313         struct hfs_btree *tree;
314         struct page *page;
315         u16 off, len;
316         u32 nidx;
317         u8 *data, byte, m;
318
319         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
320         tree = node->tree;
321         nidx = node->this;
322         node = hfs_bnode_find(tree, 0);
323         if (IS_ERR(node))
324                 return;
325         len = hfs_brec_lenoff(node, 2, &off);
326         while (nidx >= len * 8) {
327                 u32 i;
328
329                 nidx -= len * 8;
330                 i = node->next;
331                 hfs_bnode_put(node);
332                 if (!i) {
333                         /* panic */;
334                         printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
335                         return;
336                 }
337                 node = hfs_bnode_find(tree, i);
338                 if (IS_ERR(node))
339                         return;
340                 if (node->type != HFS_NODE_MAP) {
341                         /* panic */;
342                         printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
343                         hfs_bnode_put(node);
344                         return;
345                 }
346                 len = hfs_brec_lenoff(node, 0, &off);
347         }
348         off += node->page_offset + nidx / 8;
349         page = node->page[off >> PAGE_CACHE_SHIFT];
350         data = kmap(page);
351         off &= ~PAGE_CACHE_MASK;
352         m = 1 << (~nidx & 7);
353         byte = data[off];
354         if (!(byte & m)) {
355                 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
356                 kunmap(page);
357                 hfs_bnode_put(node);
358                 return;
359         }
360         data[off] = byte & ~m;
361         set_page_dirty(page);
362         kunmap(page);
363         hfs_bnode_put(node);
364         tree->free_nodes++;
365         mark_inode_dirty(tree->inode);
366 }