Merge git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/v4l-dvb
[pv_ops_mirror.git] / fs / hfs / btree.c
blob31284c77bba87b8a393d5cc78789cd13f2e02b31
1 /*
2 * linux/fs/hfs/btree.c
4 * Copyright (C) 2001
5 * Brad Boyer (flar@allandria.com)
6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
8 * Handle opening/closing btree
9 */
11 #include <linux/pagemap.h>
12 #include <linux/log2.h>
14 #include "btree.h"
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)
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;
25 tree = kzalloc(sizeof(*tree), GFP_KERNEL);
26 if (!tree)
27 return NULL;
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;
36 tree->inode = iget_locked(sb, id);
37 if (!tree->inode)
38 goto free_tree;
39 BUG_ON(!(tree->inode->i_state & I_NEW));
41 struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
42 HFS_I(tree->inode)->flags = 0;
43 init_MUTEX(&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();
59 unlock_new_inode(tree->inode);
61 mapping = tree->inode->i_mapping;
62 page = read_mapping_page(mapping, 0, NULL);
63 if (IS_ERR(page))
64 goto free_tree;
66 /* Load the header */
67 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
68 tree->root = be32_to_cpu(head->root);
69 tree->leaf_count = be32_to_cpu(head->leaf_count);
70 tree->leaf_head = be32_to_cpu(head->leaf_head);
71 tree->leaf_tail = be32_to_cpu(head->leaf_tail);
72 tree->node_count = be32_to_cpu(head->node_count);
73 tree->free_nodes = be32_to_cpu(head->free_nodes);
74 tree->attributes = be32_to_cpu(head->attributes);
75 tree->node_size = be16_to_cpu(head->node_size);
76 tree->max_key_len = be16_to_cpu(head->max_key_len);
77 tree->depth = be16_to_cpu(head->depth);
79 size = tree->node_size;
80 if (!is_power_of_2(size))
81 goto fail_page;
82 if (!tree->node_count)
83 goto fail_page;
84 if ((id == HFS_EXT_CNID) && (tree->max_key_len != HFS_MAX_EXT_KEYLEN)) {
85 printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
86 tree->max_key_len);
87 goto fail_page;
89 if ((id == HFS_CAT_CNID) && (tree->max_key_len != HFS_MAX_CAT_KEYLEN)) {
90 printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
91 tree->max_key_len);
92 goto fail_page;
95 tree->node_size_shift = ffs(size) - 1;
96 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
98 kunmap(page);
99 page_cache_release(page);
100 return tree;
102 fail_page:
103 page_cache_release(page);
104 free_tree:
105 tree->inode->i_mapping->a_ops = &hfs_aops;
106 iput(tree->inode);
107 kfree(tree);
108 return NULL;
111 /* Release resources used by a btree */
112 void hfs_btree_close(struct hfs_btree *tree)
114 struct hfs_bnode *node;
115 int i;
117 if (!tree)
118 return;
120 for (i = 0; i < NODE_HASH_SIZE; i++) {
121 while ((node = tree->node_hash[i])) {
122 tree->node_hash[i] = node->next_hash;
123 if (atomic_read(&node->refcnt))
124 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
125 node->tree->cnid, node->this, atomic_read(&node->refcnt));
126 hfs_bnode_free(node);
127 tree->node_hash_cnt--;
130 iput(tree->inode);
131 kfree(tree);
134 void hfs_btree_write(struct hfs_btree *tree)
136 struct hfs_btree_header_rec *head;
137 struct hfs_bnode *node;
138 struct page *page;
140 node = hfs_bnode_find(tree, 0);
141 if (IS_ERR(node))
142 /* panic? */
143 return;
144 /* Load the header */
145 page = node->page[0];
146 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
148 head->root = cpu_to_be32(tree->root);
149 head->leaf_count = cpu_to_be32(tree->leaf_count);
150 head->leaf_head = cpu_to_be32(tree->leaf_head);
151 head->leaf_tail = cpu_to_be32(tree->leaf_tail);
152 head->node_count = cpu_to_be32(tree->node_count);
153 head->free_nodes = cpu_to_be32(tree->free_nodes);
154 head->attributes = cpu_to_be32(tree->attributes);
155 head->depth = cpu_to_be16(tree->depth);
157 kunmap(page);
158 set_page_dirty(page);
159 hfs_bnode_put(node);
162 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
164 struct hfs_btree *tree = prev->tree;
165 struct hfs_bnode *node;
166 struct hfs_bnode_desc desc;
167 __be32 cnid;
169 node = hfs_bnode_create(tree, idx);
170 if (IS_ERR(node))
171 return node;
173 if (!tree->free_nodes)
174 panic("FIXME!!!");
175 tree->free_nodes--;
176 prev->next = idx;
177 cnid = cpu_to_be32(idx);
178 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
180 node->type = HFS_NODE_MAP;
181 node->num_recs = 1;
182 hfs_bnode_clear(node, 0, tree->node_size);
183 desc.next = 0;
184 desc.prev = 0;
185 desc.type = HFS_NODE_MAP;
186 desc.height = 0;
187 desc.num_recs = cpu_to_be16(1);
188 desc.reserved = 0;
189 hfs_bnode_write(node, &desc, 0, sizeof(desc));
190 hfs_bnode_write_u16(node, 14, 0x8000);
191 hfs_bnode_write_u16(node, tree->node_size - 2, 14);
192 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
194 return node;
197 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
199 struct hfs_bnode *node, *next_node;
200 struct page **pagep;
201 u32 nidx, idx;
202 u16 off, len;
203 u8 *data, byte, m;
204 int i;
206 while (!tree->free_nodes) {
207 struct inode *inode = tree->inode;
208 u32 count;
209 int res;
211 res = hfs_extend_file(inode);
212 if (res)
213 return ERR_PTR(res);
214 HFS_I(inode)->phys_size = inode->i_size =
215 (loff_t)HFS_I(inode)->alloc_blocks *
216 HFS_SB(tree->sb)->alloc_blksz;
217 HFS_I(inode)->fs_blocks = inode->i_size >>
218 tree->sb->s_blocksize_bits;
219 inode_set_bytes(inode, inode->i_size);
220 count = inode->i_size >> tree->node_size_shift;
221 tree->free_nodes = count - tree->node_count;
222 tree->node_count = count;
225 nidx = 0;
226 node = hfs_bnode_find(tree, nidx);
227 if (IS_ERR(node))
228 return node;
229 len = hfs_brec_lenoff(node, 2, &off);
231 off += node->page_offset;
232 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
233 data = kmap(*pagep);
234 off &= ~PAGE_CACHE_MASK;
235 idx = 0;
237 for (;;) {
238 while (len) {
239 byte = data[off];
240 if (byte != 0xff) {
241 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
242 if (!(byte & m)) {
243 idx += i;
244 data[off] |= m;
245 set_page_dirty(*pagep);
246 kunmap(*pagep);
247 tree->free_nodes--;
248 mark_inode_dirty(tree->inode);
249 hfs_bnode_put(node);
250 return hfs_bnode_create(tree, idx);
254 if (++off >= PAGE_CACHE_SIZE) {
255 kunmap(*pagep);
256 data = kmap(*++pagep);
257 off = 0;
259 idx += 8;
260 len--;
262 kunmap(*pagep);
263 nidx = node->next;
264 if (!nidx) {
265 printk(KERN_DEBUG "hfs: create new bmap node...\n");
266 next_node = hfs_bmap_new_bmap(node, idx);
267 } else
268 next_node = hfs_bnode_find(tree, nidx);
269 hfs_bnode_put(node);
270 if (IS_ERR(next_node))
271 return next_node;
272 node = next_node;
274 len = hfs_brec_lenoff(node, 0, &off);
275 off += node->page_offset;
276 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
277 data = kmap(*pagep);
278 off &= ~PAGE_CACHE_MASK;
282 void hfs_bmap_free(struct hfs_bnode *node)
284 struct hfs_btree *tree;
285 struct page *page;
286 u16 off, len;
287 u32 nidx;
288 u8 *data, byte, m;
290 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
291 tree = node->tree;
292 nidx = node->this;
293 node = hfs_bnode_find(tree, 0);
294 if (IS_ERR(node))
295 return;
296 len = hfs_brec_lenoff(node, 2, &off);
297 while (nidx >= len * 8) {
298 u32 i;
300 nidx -= len * 8;
301 i = node->next;
302 hfs_bnode_put(node);
303 if (!i) {
304 /* panic */;
305 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
306 return;
308 node = hfs_bnode_find(tree, i);
309 if (IS_ERR(node))
310 return;
311 if (node->type != HFS_NODE_MAP) {
312 /* panic */;
313 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
314 hfs_bnode_put(node);
315 return;
317 len = hfs_brec_lenoff(node, 0, &off);
319 off += node->page_offset + nidx / 8;
320 page = node->page[off >> PAGE_CACHE_SHIFT];
321 data = kmap(page);
322 off &= ~PAGE_CACHE_MASK;
323 m = 1 << (~nidx & 7);
324 byte = data[off];
325 if (!(byte & m)) {
326 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
327 kunmap(page);
328 hfs_bnode_put(node);
329 return;
331 data[off] = byte & ~m;
332 set_page_dirty(page);
333 kunmap(page);
334 hfs_bnode_put(node);
335 tree->free_nodes++;
336 mark_inode_dirty(tree->inode);