blob: 394725efa1c8b5c4354e1455ef4d277289d6d5ea [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
16struct 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 */
102void 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
124void 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
152static 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
187struct 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
272void 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}