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1/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-array.h"
8#include "dm-space-map.h"
9#include "dm-transaction-manager.h"
10
11#include <linux/export.h>
12#include <linux/device-mapper.h>
13
14#define DM_MSG_PREFIX "array"
15
16/*----------------------------------------------------------------*/
17
18/*
19 * The array is implemented as a fully populated btree, which points to
20 * blocks that contain the packed values. This is more space efficient
21 * than just using a btree since we don't store 1 key per value.
22 */
23struct array_block {
24 __le32 csum;
25 __le32 max_entries;
26 __le32 nr_entries;
27 __le32 value_size;
28 __le64 blocknr; /* Block this node is supposed to live in. */
29} __packed;
30
31/*----------------------------------------------------------------*/
32
33/*
34 * Validator methods. As usual we calculate a checksum, and also write the
35 * block location into the header (paranoia about ssds remapping areas by
36 * mistake).
37 */
38#define CSUM_XOR 595846735
39
40static void array_block_prepare_for_write(struct dm_block_validator *v,
41 struct dm_block *b,
42 size_t size_of_block)
43{
44 struct array_block *bh_le = dm_block_data(b);
45
46 bh_le->blocknr = cpu_to_le64(dm_block_location(b));
47 bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
48 size_of_block - sizeof(__le32),
49 CSUM_XOR));
50}
51
52static int array_block_check(struct dm_block_validator *v,
53 struct dm_block *b,
54 size_t size_of_block)
55{
56 struct array_block *bh_le = dm_block_data(b);
57 __le32 csum_disk;
58
59 if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
60 DMERR_LIMIT("array_block_check failed: blocknr %llu != wanted %llu",
61 (unsigned long long) le64_to_cpu(bh_le->blocknr),
62 (unsigned long long) dm_block_location(b));
63 return -ENOTBLK;
64 }
65
66 csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
67 size_of_block - sizeof(__le32),
68 CSUM_XOR));
69 if (csum_disk != bh_le->csum) {
70 DMERR_LIMIT("array_block_check failed: csum %u != wanted %u",
71 (unsigned) le32_to_cpu(csum_disk),
72 (unsigned) le32_to_cpu(bh_le->csum));
73 return -EILSEQ;
74 }
75
76 return 0;
77}
78
79static struct dm_block_validator array_validator = {
80 .name = "array",
81 .prepare_for_write = array_block_prepare_for_write,
82 .check = array_block_check
83};
84
85/*----------------------------------------------------------------*/
86
87/*
88 * Functions for manipulating the array blocks.
89 */
90
91/*
92 * Returns a pointer to a value within an array block.
93 *
94 * index - The index into _this_ specific block.
95 */
96static void *element_at(struct dm_array_info *info, struct array_block *ab,
97 unsigned index)
98{
99 unsigned char *entry = (unsigned char *) (ab + 1);
100
101 entry += index * info->value_type.size;
102
103 return entry;
104}
105
106/*
107 * Utility function that calls one of the value_type methods on every value
108 * in an array block.
109 */
110static void on_entries(struct dm_array_info *info, struct array_block *ab,
111 void (*fn)(void *, const void *))
112{
113 unsigned i, nr_entries = le32_to_cpu(ab->nr_entries);
114
115 for (i = 0; i < nr_entries; i++)
116 fn(info->value_type.context, element_at(info, ab, i));
117}
118
119/*
120 * Increment every value in an array block.
121 */
122static void inc_ablock_entries(struct dm_array_info *info, struct array_block *ab)
123{
124 struct dm_btree_value_type *vt = &info->value_type;
125
126 if (vt->inc)
127 on_entries(info, ab, vt->inc);
128}
129
130/*
131 * Decrement every value in an array block.
132 */
133static void dec_ablock_entries(struct dm_array_info *info, struct array_block *ab)
134{
135 struct dm_btree_value_type *vt = &info->value_type;
136
137 if (vt->dec)
138 on_entries(info, ab, vt->dec);
139}
140
141/*
142 * Each array block can hold this many values.
143 */
144static uint32_t calc_max_entries(size_t value_size, size_t size_of_block)
145{
146 return (size_of_block - sizeof(struct array_block)) / value_size;
147}
148
149/*
150 * Allocate a new array block. The caller will need to unlock block.
151 */
152static int alloc_ablock(struct dm_array_info *info, size_t size_of_block,
153 uint32_t max_entries,
154 struct dm_block **block, struct array_block **ab)
155{
156 int r;
157
158 r = dm_tm_new_block(info->btree_info.tm, &array_validator, block);
159 if (r)
160 return r;
161
162 (*ab) = dm_block_data(*block);
163 (*ab)->max_entries = cpu_to_le32(max_entries);
164 (*ab)->nr_entries = cpu_to_le32(0);
165 (*ab)->value_size = cpu_to_le32(info->value_type.size);
166
167 return 0;
168}
169
170/*
171 * Pad an array block out with a particular value. Every instance will
172 * cause an increment of the value_type. new_nr must always be more than
173 * the current number of entries.
174 */
175static void fill_ablock(struct dm_array_info *info, struct array_block *ab,
176 const void *value, unsigned new_nr)
177{
178 unsigned i;
179 uint32_t nr_entries;
180 struct dm_btree_value_type *vt = &info->value_type;
181
182 BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
183 BUG_ON(new_nr < le32_to_cpu(ab->nr_entries));
184
185 nr_entries = le32_to_cpu(ab->nr_entries);
186 for (i = nr_entries; i < new_nr; i++) {
187 if (vt->inc)
188 vt->inc(vt->context, value);
189 memcpy(element_at(info, ab, i), value, vt->size);
190 }
191 ab->nr_entries = cpu_to_le32(new_nr);
192}
193
194/*
195 * Remove some entries from the back of an array block. Every value
196 * removed will be decremented. new_nr must be <= the current number of
197 * entries.
198 */
199static void trim_ablock(struct dm_array_info *info, struct array_block *ab,
200 unsigned new_nr)
201{
202 unsigned i;
203 uint32_t nr_entries;
204 struct dm_btree_value_type *vt = &info->value_type;
205
206 BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
207 BUG_ON(new_nr > le32_to_cpu(ab->nr_entries));
208
209 nr_entries = le32_to_cpu(ab->nr_entries);
210 for (i = nr_entries; i > new_nr; i--)
211 if (vt->dec)
212 vt->dec(vt->context, element_at(info, ab, i - 1));
213 ab->nr_entries = cpu_to_le32(new_nr);
214}
215
216/*
217 * Read locks a block, and coerces it to an array block. The caller must
218 * unlock 'block' when finished.
219 */
220static int get_ablock(struct dm_array_info *info, dm_block_t b,
221 struct dm_block **block, struct array_block **ab)
222{
223 int r;
224
225 r = dm_tm_read_lock(info->btree_info.tm, b, &array_validator, block);
226 if (r)
227 return r;
228
229 *ab = dm_block_data(*block);
230 return 0;
231}
232
233/*
234 * Unlocks an array block.
235 */
236static void unlock_ablock(struct dm_array_info *info, struct dm_block *block)
237{
238 dm_tm_unlock(info->btree_info.tm, block);
239}
240
241/*----------------------------------------------------------------*/
242
243/*
244 * Btree manipulation.
245 */
246
247/*
248 * Looks up an array block in the btree, and then read locks it.
249 *
250 * index is the index of the index of the array_block, (ie. the array index
251 * / max_entries).
252 */
253static int lookup_ablock(struct dm_array_info *info, dm_block_t root,
254 unsigned index, struct dm_block **block,
255 struct array_block **ab)
256{
257 int r;
258 uint64_t key = index;
259 __le64 block_le;
260
261 r = dm_btree_lookup(&info->btree_info, root, &key, &block_le);
262 if (r)
263 return r;
264
265 return get_ablock(info, le64_to_cpu(block_le), block, ab);
266}
267
268/*
269 * Insert an array block into the btree. The block is _not_ unlocked.
270 */
271static int insert_ablock(struct dm_array_info *info, uint64_t index,
272 struct dm_block *block, dm_block_t *root)
273{
274 __le64 block_le = cpu_to_le64(dm_block_location(block));
275
276 __dm_bless_for_disk(block_le);
277 return dm_btree_insert(&info->btree_info, *root, &index, &block_le, root);
278}
279
280/*----------------------------------------------------------------*/
281
282static int __shadow_ablock(struct dm_array_info *info, dm_block_t b,
283 struct dm_block **block, struct array_block **ab)
284{
285 int inc;
286 int r = dm_tm_shadow_block(info->btree_info.tm, b,
287 &array_validator, block, &inc);
288 if (r)
289 return r;
290
291 *ab = dm_block_data(*block);
292 if (inc)
293 inc_ablock_entries(info, *ab);
294
295 return 0;
296}
297
298/*
299 * The shadow op will often be a noop. Only insert if it really
300 * copied data.
301 */
302static int __reinsert_ablock(struct dm_array_info *info, unsigned index,
303 struct dm_block *block, dm_block_t b,
304 dm_block_t *root)
305{
306 int r = 0;
307
308 if (dm_block_location(block) != b) {
309 /*
310 * dm_tm_shadow_block will have already decremented the old
311 * block, but it is still referenced by the btree. We
312 * increment to stop the insert decrementing it below zero
313 * when overwriting the old value.
314 */
315 dm_tm_inc(info->btree_info.tm, b);
316 r = insert_ablock(info, index, block, root);
317 }
318
319 return r;
320}
321
322/*
323 * Looks up an array block in the btree. Then shadows it, and updates the
324 * btree to point to this new shadow. 'root' is an input/output parameter
325 * for both the current root block, and the new one.
326 */
327static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
328 unsigned index, struct dm_block **block,
329 struct array_block **ab)
330{
331 int r;
332 uint64_t key = index;
333 dm_block_t b;
334 __le64 block_le;
335
336 r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
337 if (r)
338 return r;
339 b = le64_to_cpu(block_le);
340
341 r = __shadow_ablock(info, b, block, ab);
342 if (r)
343 return r;
344
345 return __reinsert_ablock(info, index, *block, b, root);
346}
347
348/*
349 * Allocate an new array block, and fill it with some values.
350 */
351static int insert_new_ablock(struct dm_array_info *info, size_t size_of_block,
352 uint32_t max_entries,
353 unsigned block_index, uint32_t nr,
354 const void *value, dm_block_t *root)
355{
356 int r;
357 struct dm_block *block;
358 struct array_block *ab;
359
360 r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
361 if (r)
362 return r;
363
364 fill_ablock(info, ab, value, nr);
365 r = insert_ablock(info, block_index, block, root);
366 unlock_ablock(info, block);
367
368 return r;
369}
370
371static int insert_full_ablocks(struct dm_array_info *info, size_t size_of_block,
372 unsigned begin_block, unsigned end_block,
373 unsigned max_entries, const void *value,
374 dm_block_t *root)
375{
376 int r = 0;
377
378 for (; !r && begin_block != end_block; begin_block++)
379 r = insert_new_ablock(info, size_of_block, max_entries, begin_block, max_entries, value, root);
380
381 return r;
382}
383
384/*
385 * There are a bunch of functions involved with resizing an array. This
386 * structure holds information that commonly needed by them. Purely here
387 * to reduce parameter count.
388 */
389struct resize {
390 /*
391 * Describes the array.
392 */
393 struct dm_array_info *info;
394
395 /*
396 * The current root of the array. This gets updated.
397 */
398 dm_block_t root;
399
400 /*
401 * Metadata block size. Used to calculate the nr entries in an
402 * array block.
403 */
404 size_t size_of_block;
405
406 /*
407 * Maximum nr entries in an array block.
408 */
409 unsigned max_entries;
410
411 /*
412 * nr of completely full blocks in the array.
413 *
414 * 'old' refers to before the resize, 'new' after.
415 */
416 unsigned old_nr_full_blocks, new_nr_full_blocks;
417
418 /*
419 * Number of entries in the final block. 0 iff only full blocks in
420 * the array.
421 */
422 unsigned old_nr_entries_in_last_block, new_nr_entries_in_last_block;
423
424 /*
425 * The default value used when growing the array.
426 */
427 const void *value;
428};
429
430/*
431 * Removes a consecutive set of array blocks from the btree. The values
432 * in block are decremented as a side effect of the btree remove.
433 *
434 * begin_index - the index of the first array block to remove.
435 * end_index - the one-past-the-end value. ie. this block is not removed.
436 */
437static int drop_blocks(struct resize *resize, unsigned begin_index,
438 unsigned end_index)
439{
440 int r;
441
442 while (begin_index != end_index) {
443 uint64_t key = begin_index++;
444 r = dm_btree_remove(&resize->info->btree_info, resize->root,
445 &key, &resize->root);
446 if (r)
447 return r;
448 }
449
450 return 0;
451}
452
453/*
454 * Calculates how many blocks are needed for the array.
455 */
456static unsigned total_nr_blocks_needed(unsigned nr_full_blocks,
457 unsigned nr_entries_in_last_block)
458{
459 return nr_full_blocks + (nr_entries_in_last_block ? 1 : 0);
460}
461
462/*
463 * Shrink an array.
464 */
465static int shrink(struct resize *resize)
466{
467 int r;
468 unsigned begin, end;
469 struct dm_block *block;
470 struct array_block *ab;
471
472 /*
473 * Lose some blocks from the back?
474 */
475 if (resize->new_nr_full_blocks < resize->old_nr_full_blocks) {
476 begin = total_nr_blocks_needed(resize->new_nr_full_blocks,
477 resize->new_nr_entries_in_last_block);
478 end = total_nr_blocks_needed(resize->old_nr_full_blocks,
479 resize->old_nr_entries_in_last_block);
480
481 r = drop_blocks(resize, begin, end);
482 if (r)
483 return r;
484 }
485
486 /*
487 * Trim the new tail block
488 */
489 if (resize->new_nr_entries_in_last_block) {
490 r = shadow_ablock(resize->info, &resize->root,
491 resize->new_nr_full_blocks, &block, &ab);
492 if (r)
493 return r;
494
495 trim_ablock(resize->info, ab, resize->new_nr_entries_in_last_block);
496 unlock_ablock(resize->info, block);
497 }
498
499 return 0;
500}
501
502/*
503 * Grow an array.
504 */
505static int grow_extend_tail_block(struct resize *resize, uint32_t new_nr_entries)
506{
507 int r;
508 struct dm_block *block;
509 struct array_block *ab;
510
511 r = shadow_ablock(resize->info, &resize->root,
512 resize->old_nr_full_blocks, &block, &ab);
513 if (r)
514 return r;
515
516 fill_ablock(resize->info, ab, resize->value, new_nr_entries);
517 unlock_ablock(resize->info, block);
518
519 return r;
520}
521
522static int grow_add_tail_block(struct resize *resize)
523{
524 return insert_new_ablock(resize->info, resize->size_of_block,
525 resize->max_entries,
526 resize->new_nr_full_blocks,
527 resize->new_nr_entries_in_last_block,
528 resize->value, &resize->root);
529}
530
531static int grow_needs_more_blocks(struct resize *resize)
532{
533 int r;
534 unsigned old_nr_blocks = resize->old_nr_full_blocks;
535
536 if (resize->old_nr_entries_in_last_block > 0) {
537 old_nr_blocks++;
538
539 r = grow_extend_tail_block(resize, resize->max_entries);
540 if (r)
541 return r;
542 }
543
544 r = insert_full_ablocks(resize->info, resize->size_of_block,
545 old_nr_blocks,
546 resize->new_nr_full_blocks,
547 resize->max_entries, resize->value,
548 &resize->root);
549 if (r)
550 return r;
551
552 if (resize->new_nr_entries_in_last_block)
553 r = grow_add_tail_block(resize);
554
555 return r;
556}
557
558static int grow(struct resize *resize)
559{
560 if (resize->new_nr_full_blocks > resize->old_nr_full_blocks)
561 return grow_needs_more_blocks(resize);
562
563 else if (resize->old_nr_entries_in_last_block)
564 return grow_extend_tail_block(resize, resize->new_nr_entries_in_last_block);
565
566 else
567 return grow_add_tail_block(resize);
568}
569
570/*----------------------------------------------------------------*/
571
572/*
573 * These are the value_type functions for the btree elements, which point
574 * to array blocks.
575 */
576static void block_inc(void *context, const void *value)
577{
578 __le64 block_le;
579 struct dm_array_info *info = context;
580
581 memcpy(&block_le, value, sizeof(block_le));
582 dm_tm_inc(info->btree_info.tm, le64_to_cpu(block_le));
583}
584
585static void block_dec(void *context, const void *value)
586{
587 int r;
588 uint64_t b;
589 __le64 block_le;
590 uint32_t ref_count;
591 struct dm_block *block;
592 struct array_block *ab;
593 struct dm_array_info *info = context;
594
595 memcpy(&block_le, value, sizeof(block_le));
596 b = le64_to_cpu(block_le);
597
598 r = dm_tm_ref(info->btree_info.tm, b, &ref_count);
599 if (r) {
600 DMERR_LIMIT("couldn't get reference count for block %llu",
601 (unsigned long long) b);
602 return;
603 }
604
605 if (ref_count == 1) {
606 /*
607 * We're about to drop the last reference to this ablock.
608 * So we need to decrement the ref count of the contents.
609 */
610 r = get_ablock(info, b, &block, &ab);
611 if (r) {
612 DMERR_LIMIT("couldn't get array block %llu",
613 (unsigned long long) b);
614 return;
615 }
616
617 dec_ablock_entries(info, ab);
618 unlock_ablock(info, block);
619 }
620
621 dm_tm_dec(info->btree_info.tm, b);
622}
623
624static int block_equal(void *context, const void *value1, const void *value2)
625{
626 return !memcmp(value1, value2, sizeof(__le64));
627}
628
629/*----------------------------------------------------------------*/
630
631void dm_array_info_init(struct dm_array_info *info,
632 struct dm_transaction_manager *tm,
633 struct dm_btree_value_type *vt)
634{
635 struct dm_btree_value_type *bvt = &info->btree_info.value_type;
636
637 memcpy(&info->value_type, vt, sizeof(info->value_type));
638 info->btree_info.tm = tm;
639 info->btree_info.levels = 1;
640
641 bvt->context = info;
642 bvt->size = sizeof(__le64);
643 bvt->inc = block_inc;
644 bvt->dec = block_dec;
645 bvt->equal = block_equal;
646}
647EXPORT_SYMBOL_GPL(dm_array_info_init);
648
649int dm_array_empty(struct dm_array_info *info, dm_block_t *root)
650{
651 return dm_btree_empty(&info->btree_info, root);
652}
653EXPORT_SYMBOL_GPL(dm_array_empty);
654
655static int array_resize(struct dm_array_info *info, dm_block_t root,
656 uint32_t old_size, uint32_t new_size,
657 const void *value, dm_block_t *new_root)
658{
659 int r;
660 struct resize resize;
661
662 if (old_size == new_size) {
663 *new_root = root;
664 return 0;
665 }
666
667 resize.info = info;
668 resize.root = root;
669 resize.size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
670 resize.max_entries = calc_max_entries(info->value_type.size,
671 resize.size_of_block);
672
673 resize.old_nr_full_blocks = old_size / resize.max_entries;
674 resize.old_nr_entries_in_last_block = old_size % resize.max_entries;
675 resize.new_nr_full_blocks = new_size / resize.max_entries;
676 resize.new_nr_entries_in_last_block = new_size % resize.max_entries;
677 resize.value = value;
678
679 r = ((new_size > old_size) ? grow : shrink)(&resize);
680 if (r)
681 return r;
682
683 *new_root = resize.root;
684 return 0;
685}
686
687int dm_array_resize(struct dm_array_info *info, dm_block_t root,
688 uint32_t old_size, uint32_t new_size,
689 const void *value, dm_block_t *new_root)
690 __dm_written_to_disk(value)
691{
692 int r = array_resize(info, root, old_size, new_size, value, new_root);
693 __dm_unbless_for_disk(value);
694 return r;
695}
696EXPORT_SYMBOL_GPL(dm_array_resize);
697
698static int populate_ablock_with_values(struct dm_array_info *info, struct array_block *ab,
699 value_fn fn, void *context, unsigned base, unsigned new_nr)
700{
701 int r;
702 unsigned i;
703 struct dm_btree_value_type *vt = &info->value_type;
704
705 BUG_ON(le32_to_cpu(ab->nr_entries));
706 BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
707
708 for (i = 0; i < new_nr; i++) {
709 r = fn(base + i, element_at(info, ab, i), context);
710 if (r)
711 return r;
712
713 if (vt->inc)
714 vt->inc(vt->context, element_at(info, ab, i));
715 }
716
717 ab->nr_entries = cpu_to_le32(new_nr);
718 return 0;
719}
720
721int dm_array_new(struct dm_array_info *info, dm_block_t *root,
722 uint32_t size, value_fn fn, void *context)
723{
724 int r;
725 struct dm_block *block;
726 struct array_block *ab;
727 unsigned block_index, end_block, size_of_block, max_entries;
728
729 r = dm_array_empty(info, root);
730 if (r)
731 return r;
732
733 size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
734 max_entries = calc_max_entries(info->value_type.size, size_of_block);
735 end_block = dm_div_up(size, max_entries);
736
737 for (block_index = 0; block_index != end_block; block_index++) {
738 r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
739 if (r)
740 break;
741
742 r = populate_ablock_with_values(info, ab, fn, context,
743 block_index * max_entries,
744 min(max_entries, size));
745 if (r) {
746 unlock_ablock(info, block);
747 break;
748 }
749
750 r = insert_ablock(info, block_index, block, root);
751 unlock_ablock(info, block);
752 if (r)
753 break;
754
755 size -= max_entries;
756 }
757
758 return r;
759}
760EXPORT_SYMBOL_GPL(dm_array_new);
761
762int dm_array_del(struct dm_array_info *info, dm_block_t root)
763{
764 return dm_btree_del(&info->btree_info, root);
765}
766EXPORT_SYMBOL_GPL(dm_array_del);
767
768int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
769 uint32_t index, void *value_le)
770{
771 int r;
772 struct dm_block *block;
773 struct array_block *ab;
774 size_t size_of_block;
775 unsigned entry, max_entries;
776
777 size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
778 max_entries = calc_max_entries(info->value_type.size, size_of_block);
779
780 r = lookup_ablock(info, root, index / max_entries, &block, &ab);
781 if (r)
782 return r;
783
784 entry = index % max_entries;
785 if (entry >= le32_to_cpu(ab->nr_entries))
786 r = -ENODATA;
787 else
788 memcpy(value_le, element_at(info, ab, entry),
789 info->value_type.size);
790
791 unlock_ablock(info, block);
792 return r;
793}
794EXPORT_SYMBOL_GPL(dm_array_get_value);
795
796static int array_set_value(struct dm_array_info *info, dm_block_t root,
797 uint32_t index, const void *value, dm_block_t *new_root)
798{
799 int r;
800 struct dm_block *block;
801 struct array_block *ab;
802 size_t size_of_block;
803 unsigned max_entries;
804 unsigned entry;
805 void *old_value;
806 struct dm_btree_value_type *vt = &info->value_type;
807
808 size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
809 max_entries = calc_max_entries(info->value_type.size, size_of_block);
810
811 r = shadow_ablock(info, &root, index / max_entries, &block, &ab);
812 if (r)
813 return r;
814 *new_root = root;
815
816 entry = index % max_entries;
817 if (entry >= le32_to_cpu(ab->nr_entries)) {
818 r = -ENODATA;
819 goto out;
820 }
821
822 old_value = element_at(info, ab, entry);
823 if (vt->dec &&
824 (!vt->equal || !vt->equal(vt->context, old_value, value))) {
825 vt->dec(vt->context, old_value);
826 if (vt->inc)
827 vt->inc(vt->context, value);
828 }
829
830 memcpy(old_value, value, info->value_type.size);
831
832out:
833 unlock_ablock(info, block);
834 return r;
835}
836
837int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
838 uint32_t index, const void *value, dm_block_t *new_root)
839 __dm_written_to_disk(value)
840{
841 int r;
842
843 r = array_set_value(info, root, index, value, new_root);
844 __dm_unbless_for_disk(value);
845 return r;
846}
847EXPORT_SYMBOL_GPL(dm_array_set_value);
848
849struct walk_info {
850 struct dm_array_info *info;
851 int (*fn)(void *context, uint64_t key, void *leaf);
852 void *context;
853};
854
855static int walk_ablock(void *context, uint64_t *keys, void *leaf)
856{
857 struct walk_info *wi = context;
858
859 int r;
860 unsigned i;
861 __le64 block_le;
862 unsigned nr_entries, max_entries;
863 struct dm_block *block;
864 struct array_block *ab;
865
866 memcpy(&block_le, leaf, sizeof(block_le));
867 r = get_ablock(wi->info, le64_to_cpu(block_le), &block, &ab);
868 if (r)
869 return r;
870
871 max_entries = le32_to_cpu(ab->max_entries);
872 nr_entries = le32_to_cpu(ab->nr_entries);
873 for (i = 0; i < nr_entries; i++) {
874 r = wi->fn(wi->context, keys[0] * max_entries + i,
875 element_at(wi->info, ab, i));
876
877 if (r)
878 break;
879 }
880
881 unlock_ablock(wi->info, block);
882 return r;
883}
884
885int dm_array_walk(struct dm_array_info *info, dm_block_t root,
886 int (*fn)(void *, uint64_t key, void *leaf),
887 void *context)
888{
889 struct walk_info wi;
890
891 wi.info = info;
892 wi.fn = fn;
893 wi.context = context;
894
895 return dm_btree_walk(&info->btree_info, root, walk_ablock, &wi);
896}
897EXPORT_SYMBOL_GPL(dm_array_walk);
898
899/*----------------------------------------------------------------*/
900
901static int load_ablock(struct dm_array_cursor *c)
902{
903 int r;
904 __le64 value_le;
905 uint64_t key;
906
907 if (c->block)
908 unlock_ablock(c->info, c->block);
909
910 c->block = NULL;
911 c->ab = NULL;
912 c->index = 0;
913
914 r = dm_btree_cursor_get_value(&c->cursor, &key, &value_le);
915 if (r) {
916 DMERR("dm_btree_cursor_get_value failed");
917 dm_btree_cursor_end(&c->cursor);
918
919 } else {
920 r = get_ablock(c->info, le64_to_cpu(value_le), &c->block, &c->ab);
921 if (r) {
922 DMERR("get_ablock failed");
923 dm_btree_cursor_end(&c->cursor);
924 }
925 }
926
927 return r;
928}
929
930int dm_array_cursor_begin(struct dm_array_info *info, dm_block_t root,
931 struct dm_array_cursor *c)
932{
933 int r;
934
935 memset(c, 0, sizeof(*c));
936 c->info = info;
937 r = dm_btree_cursor_begin(&info->btree_info, root, true, &c->cursor);
938 if (r) {
939 DMERR("couldn't create btree cursor");
940 return r;
941 }
942
943 return load_ablock(c);
944}
945EXPORT_SYMBOL_GPL(dm_array_cursor_begin);
946
947void dm_array_cursor_end(struct dm_array_cursor *c)
948{
949 if (c->block) {
950 unlock_ablock(c->info, c->block);
951 dm_btree_cursor_end(&c->cursor);
952 }
953}
954EXPORT_SYMBOL_GPL(dm_array_cursor_end);
955
956int dm_array_cursor_next(struct dm_array_cursor *c)
957{
958 int r;
959
960 if (!c->block)
961 return -ENODATA;
962
963 c->index++;
964
965 if (c->index >= le32_to_cpu(c->ab->nr_entries)) {
966 r = dm_btree_cursor_next(&c->cursor);
967 if (r)
968 return r;
969
970 r = load_ablock(c);
971 if (r)
972 return r;
973 }
974
975 return 0;
976}
977EXPORT_SYMBOL_GPL(dm_array_cursor_next);
978
979int dm_array_cursor_skip(struct dm_array_cursor *c, uint32_t count)
980{
981 int r;
982
983 do {
984 uint32_t remaining = le32_to_cpu(c->ab->nr_entries) - c->index;
985
986 if (count < remaining) {
987 c->index += count;
988 return 0;
989 }
990
991 count -= remaining;
992 r = dm_array_cursor_next(c);
993
994 } while (!r);
995
996 return r;
997}
998EXPORT_SYMBOL_GPL(dm_array_cursor_skip);
999
1000void dm_array_cursor_get_value(struct dm_array_cursor *c, void **value_le)
1001{
1002 *value_le = element_at(c->info, c->ab, c->index);
1003}
1004EXPORT_SYMBOL_GPL(dm_array_cursor_get_value);
1005
1006/*----------------------------------------------------------------*/