Root/fs/hfs/brec.c

1/*
2 * linux/fs/hfs/brec.c
3 *
4 * Copyright (C) 2001
5 * Brad Boyer (flar@allandria.com)
6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
7 *
8 * Handle individual btree records
9 */
10
11#include "btree.h"
12
13static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
14static int hfs_brec_update_parent(struct hfs_find_data *fd);
15static int hfs_btree_inc_height(struct hfs_btree *tree);
16
17/* Get the length and offset of the given record in the given node */
18u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
19{
20    __be16 retval[2];
21    u16 dataoff;
22
23    dataoff = node->tree->node_size - (rec + 2) * 2;
24    hfs_bnode_read(node, retval, dataoff, 4);
25    *off = be16_to_cpu(retval[1]);
26    return be16_to_cpu(retval[0]) - *off;
27}
28
29/* Get the length of the key from a keyed record */
30u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
31{
32    u16 retval, recoff;
33
34    if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
35        return 0;
36
37    if ((node->type == HFS_NODE_INDEX) &&
38       !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
39        if (node->tree->attributes & HFS_TREE_BIGKEYS)
40            retval = node->tree->max_key_len + 2;
41        else
42            retval = node->tree->max_key_len + 1;
43    } else {
44        recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
45        if (!recoff)
46            return 0;
47        if (node->tree->attributes & HFS_TREE_BIGKEYS) {
48            retval = hfs_bnode_read_u16(node, recoff) + 2;
49            if (retval > node->tree->max_key_len + 2) {
50                printk(KERN_ERR "hfs: keylen %d too large\n",
51                    retval);
52                retval = 0;
53            }
54        } else {
55            retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
56            if (retval > node->tree->max_key_len + 1) {
57                printk(KERN_ERR "hfs: keylen %d too large\n",
58                    retval);
59                retval = 0;
60            }
61        }
62    }
63    return retval;
64}
65
66int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
67{
68    struct hfs_btree *tree;
69    struct hfs_bnode *node, *new_node;
70    int size, key_len, rec;
71    int data_off, end_off;
72    int idx_rec_off, data_rec_off, end_rec_off;
73    __be32 cnid;
74
75    tree = fd->tree;
76    if (!fd->bnode) {
77        if (!tree->root)
78            hfs_btree_inc_height(tree);
79        fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
80        if (IS_ERR(fd->bnode))
81            return PTR_ERR(fd->bnode);
82        fd->record = -1;
83    }
84    new_node = NULL;
85    key_len = (fd->search_key->key_len | 1) + 1;
86again:
87    /* new record idx and complete record size */
88    rec = fd->record + 1;
89    size = key_len + entry_len;
90
91    node = fd->bnode;
92    hfs_bnode_dump(node);
93    /* get last offset */
94    end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
95    end_off = hfs_bnode_read_u16(node, end_rec_off);
96    end_rec_off -= 2;
97    dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
98    if (size > end_rec_off - end_off) {
99        if (new_node)
100            panic("not enough room!\n");
101        new_node = hfs_bnode_split(fd);
102        if (IS_ERR(new_node))
103            return PTR_ERR(new_node);
104        goto again;
105    }
106    if (node->type == HFS_NODE_LEAF) {
107        tree->leaf_count++;
108        mark_inode_dirty(tree->inode);
109    }
110    node->num_recs++;
111    /* write new last offset */
112    hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
113    hfs_bnode_write_u16(node, end_rec_off, end_off + size);
114    data_off = end_off;
115    data_rec_off = end_rec_off + 2;
116    idx_rec_off = tree->node_size - (rec + 1) * 2;
117    if (idx_rec_off == data_rec_off)
118        goto skip;
119    /* move all following entries */
120    do {
121        data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
122        hfs_bnode_write_u16(node, data_rec_off, data_off + size);
123        data_rec_off += 2;
124    } while (data_rec_off < idx_rec_off);
125
126    /* move data away */
127    hfs_bnode_move(node, data_off + size, data_off,
128               end_off - data_off);
129
130skip:
131    hfs_bnode_write(node, fd->search_key, data_off, key_len);
132    hfs_bnode_write(node, entry, data_off + key_len, entry_len);
133    hfs_bnode_dump(node);
134
135    if (new_node) {
136        /* update parent key if we inserted a key
137         * at the start of the first node
138         */
139        if (!rec && new_node != node)
140            hfs_brec_update_parent(fd);
141
142        hfs_bnode_put(fd->bnode);
143        if (!new_node->parent) {
144            hfs_btree_inc_height(tree);
145            new_node->parent = tree->root;
146        }
147        fd->bnode = hfs_bnode_find(tree, new_node->parent);
148
149        /* create index data entry */
150        cnid = cpu_to_be32(new_node->this);
151        entry = &cnid;
152        entry_len = sizeof(cnid);
153
154        /* get index key */
155        hfs_bnode_read_key(new_node, fd->search_key, 14);
156        __hfs_brec_find(fd->bnode, fd);
157
158        hfs_bnode_put(new_node);
159        new_node = NULL;
160
161        if (tree->attributes & HFS_TREE_VARIDXKEYS)
162            key_len = fd->search_key->key_len + 1;
163        else {
164            fd->search_key->key_len = tree->max_key_len;
165            key_len = tree->max_key_len + 1;
166        }
167        goto again;
168    }
169
170    if (!rec)
171        hfs_brec_update_parent(fd);
172
173    return 0;
174}
175
176int hfs_brec_remove(struct hfs_find_data *fd)
177{
178    struct hfs_btree *tree;
179    struct hfs_bnode *node, *parent;
180    int end_off, rec_off, data_off, size;
181
182    tree = fd->tree;
183    node = fd->bnode;
184again:
185    rec_off = tree->node_size - (fd->record + 2) * 2;
186    end_off = tree->node_size - (node->num_recs + 1) * 2;
187
188    if (node->type == HFS_NODE_LEAF) {
189        tree->leaf_count--;
190        mark_inode_dirty(tree->inode);
191    }
192    hfs_bnode_dump(node);
193    dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
194    if (!--node->num_recs) {
195        hfs_bnode_unlink(node);
196        if (!node->parent)
197            return 0;
198        parent = hfs_bnode_find(tree, node->parent);
199        if (IS_ERR(parent))
200            return PTR_ERR(parent);
201        hfs_bnode_put(node);
202        node = fd->bnode = parent;
203
204        __hfs_brec_find(node, fd);
205        goto again;
206    }
207    hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
208
209    if (rec_off == end_off)
210        goto skip;
211    size = fd->keylength + fd->entrylength;
212
213    do {
214        data_off = hfs_bnode_read_u16(node, rec_off);
215        hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
216        rec_off -= 2;
217    } while (rec_off >= end_off);
218
219    /* fill hole */
220    hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
221               data_off - fd->keyoffset - size);
222skip:
223    hfs_bnode_dump(node);
224    if (!fd->record)
225        hfs_brec_update_parent(fd);
226    return 0;
227}
228
229static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
230{
231    struct hfs_btree *tree;
232    struct hfs_bnode *node, *new_node, *next_node;
233    struct hfs_bnode_desc node_desc;
234    int num_recs, new_rec_off, new_off, old_rec_off;
235    int data_start, data_end, size;
236
237    tree = fd->tree;
238    node = fd->bnode;
239    new_node = hfs_bmap_alloc(tree);
240    if (IS_ERR(new_node))
241        return new_node;
242    hfs_bnode_get(node);
243    dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
244        node->this, new_node->this, node->next);
245    new_node->next = node->next;
246    new_node->prev = node->this;
247    new_node->parent = node->parent;
248    new_node->type = node->type;
249    new_node->height = node->height;
250
251    if (node->next)
252        next_node = hfs_bnode_find(tree, node->next);
253    else
254        next_node = NULL;
255
256    if (IS_ERR(next_node)) {
257        hfs_bnode_put(node);
258        hfs_bnode_put(new_node);
259        return next_node;
260    }
261
262    size = tree->node_size / 2 - node->num_recs * 2 - 14;
263    old_rec_off = tree->node_size - 4;
264    num_recs = 1;
265    for (;;) {
266        data_start = hfs_bnode_read_u16(node, old_rec_off);
267        if (data_start > size)
268            break;
269        old_rec_off -= 2;
270        if (++num_recs < node->num_recs)
271            continue;
272        /* panic? */
273        hfs_bnode_put(node);
274        hfs_bnode_put(new_node);
275        if (next_node)
276            hfs_bnode_put(next_node);
277        return ERR_PTR(-ENOSPC);
278    }
279
280    if (fd->record + 1 < num_recs) {
281        /* new record is in the lower half,
282         * so leave some more space there
283         */
284        old_rec_off += 2;
285        num_recs--;
286        data_start = hfs_bnode_read_u16(node, old_rec_off);
287    } else {
288        hfs_bnode_put(node);
289        hfs_bnode_get(new_node);
290        fd->bnode = new_node;
291        fd->record -= num_recs;
292        fd->keyoffset -= data_start - 14;
293        fd->entryoffset -= data_start - 14;
294    }
295    new_node->num_recs = node->num_recs - num_recs;
296    node->num_recs = num_recs;
297
298    new_rec_off = tree->node_size - 2;
299    new_off = 14;
300    size = data_start - new_off;
301    num_recs = new_node->num_recs;
302    data_end = data_start;
303    while (num_recs) {
304        hfs_bnode_write_u16(new_node, new_rec_off, new_off);
305        old_rec_off -= 2;
306        new_rec_off -= 2;
307        data_end = hfs_bnode_read_u16(node, old_rec_off);
308        new_off = data_end - size;
309        num_recs--;
310    }
311    hfs_bnode_write_u16(new_node, new_rec_off, new_off);
312    hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
313
314    /* update new bnode header */
315    node_desc.next = cpu_to_be32(new_node->next);
316    node_desc.prev = cpu_to_be32(new_node->prev);
317    node_desc.type = new_node->type;
318    node_desc.height = new_node->height;
319    node_desc.num_recs = cpu_to_be16(new_node->num_recs);
320    node_desc.reserved = 0;
321    hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
322
323    /* update previous bnode header */
324    node->next = new_node->this;
325    hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
326    node_desc.next = cpu_to_be32(node->next);
327    node_desc.num_recs = cpu_to_be16(node->num_recs);
328    hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
329
330    /* update next bnode header */
331    if (next_node) {
332        next_node->prev = new_node->this;
333        hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
334        node_desc.prev = cpu_to_be32(next_node->prev);
335        hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
336        hfs_bnode_put(next_node);
337    } else if (node->this == tree->leaf_tail) {
338        /* if there is no next node, this might be the new tail */
339        tree->leaf_tail = new_node->this;
340        mark_inode_dirty(tree->inode);
341    }
342
343    hfs_bnode_dump(node);
344    hfs_bnode_dump(new_node);
345    hfs_bnode_put(node);
346
347    return new_node;
348}
349
350static int hfs_brec_update_parent(struct hfs_find_data *fd)
351{
352    struct hfs_btree *tree;
353    struct hfs_bnode *node, *new_node, *parent;
354    int newkeylen, diff;
355    int rec, rec_off, end_rec_off;
356    int start_off, end_off;
357
358    tree = fd->tree;
359    node = fd->bnode;
360    new_node = NULL;
361    if (!node->parent)
362        return 0;
363
364again:
365    parent = hfs_bnode_find(tree, node->parent);
366    if (IS_ERR(parent))
367        return PTR_ERR(parent);
368    __hfs_brec_find(parent, fd);
369    hfs_bnode_dump(parent);
370    rec = fd->record;
371
372    /* size difference between old and new key */
373    if (tree->attributes & HFS_TREE_VARIDXKEYS)
374        newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
375    else
376        fd->keylength = newkeylen = tree->max_key_len + 1;
377    dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
378
379    rec_off = tree->node_size - (rec + 2) * 2;
380    end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
381    diff = newkeylen - fd->keylength;
382    if (!diff)
383        goto skip;
384    if (diff > 0) {
385        end_off = hfs_bnode_read_u16(parent, end_rec_off);
386        if (end_rec_off - end_off < diff) {
387
388            printk(KERN_DEBUG "hfs: splitting index node...\n");
389            fd->bnode = parent;
390            new_node = hfs_bnode_split(fd);
391            if (IS_ERR(new_node))
392                return PTR_ERR(new_node);
393            parent = fd->bnode;
394            rec = fd->record;
395            rec_off = tree->node_size - (rec + 2) * 2;
396            end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
397        }
398    }
399
400    end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
401    hfs_bnode_write_u16(parent, rec_off, start_off + diff);
402    start_off -= 4; /* move previous cnid too */
403
404    while (rec_off > end_rec_off) {
405        rec_off -= 2;
406        end_off = hfs_bnode_read_u16(parent, rec_off);
407        hfs_bnode_write_u16(parent, rec_off, end_off + diff);
408    }
409    hfs_bnode_move(parent, start_off + diff, start_off,
410               end_off - start_off);
411skip:
412    hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
413    if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
414        hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
415    hfs_bnode_dump(parent);
416
417    hfs_bnode_put(node);
418    node = parent;
419
420    if (new_node) {
421        __be32 cnid;
422
423        fd->bnode = hfs_bnode_find(tree, new_node->parent);
424        /* create index key and entry */
425        hfs_bnode_read_key(new_node, fd->search_key, 14);
426        cnid = cpu_to_be32(new_node->this);
427
428        __hfs_brec_find(fd->bnode, fd);
429        hfs_brec_insert(fd, &cnid, sizeof(cnid));
430        hfs_bnode_put(fd->bnode);
431        hfs_bnode_put(new_node);
432
433        if (!rec) {
434            if (new_node == node)
435                goto out;
436            /* restore search_key */
437            hfs_bnode_read_key(node, fd->search_key, 14);
438        }
439    }
440
441    if (!rec && node->parent)
442        goto again;
443out:
444    fd->bnode = node;
445    return 0;
446}
447
448static int hfs_btree_inc_height(struct hfs_btree *tree)
449{
450    struct hfs_bnode *node, *new_node;
451    struct hfs_bnode_desc node_desc;
452    int key_size, rec;
453    __be32 cnid;
454
455    node = NULL;
456    if (tree->root) {
457        node = hfs_bnode_find(tree, tree->root);
458        if (IS_ERR(node))
459            return PTR_ERR(node);
460    }
461    new_node = hfs_bmap_alloc(tree);
462    if (IS_ERR(new_node)) {
463        hfs_bnode_put(node);
464        return PTR_ERR(new_node);
465    }
466
467    tree->root = new_node->this;
468    if (!tree->depth) {
469        tree->leaf_head = tree->leaf_tail = new_node->this;
470        new_node->type = HFS_NODE_LEAF;
471        new_node->num_recs = 0;
472    } else {
473        new_node->type = HFS_NODE_INDEX;
474        new_node->num_recs = 1;
475    }
476    new_node->parent = 0;
477    new_node->next = 0;
478    new_node->prev = 0;
479    new_node->height = ++tree->depth;
480
481    node_desc.next = cpu_to_be32(new_node->next);
482    node_desc.prev = cpu_to_be32(new_node->prev);
483    node_desc.type = new_node->type;
484    node_desc.height = new_node->height;
485    node_desc.num_recs = cpu_to_be16(new_node->num_recs);
486    node_desc.reserved = 0;
487    hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
488
489    rec = tree->node_size - 2;
490    hfs_bnode_write_u16(new_node, rec, 14);
491
492    if (node) {
493        /* insert old root idx into new root */
494        node->parent = tree->root;
495        if (node->type == HFS_NODE_LEAF ||
496            tree->attributes & HFS_TREE_VARIDXKEYS)
497            key_size = hfs_bnode_read_u8(node, 14) + 1;
498        else
499            key_size = tree->max_key_len + 1;
500        hfs_bnode_copy(new_node, 14, node, 14, key_size);
501
502        if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
503            key_size = tree->max_key_len + 1;
504            hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
505        }
506        key_size = (key_size + 1) & -2;
507        cnid = cpu_to_be32(node->this);
508        hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
509
510        rec -= 2;
511        hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
512
513        hfs_bnode_put(node);
514    }
515    hfs_bnode_put(new_node);
516    mark_inode_dirty(tree->inode);
517
518    return 0;
519}
520

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