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