1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Red Hat, Inc.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-array.h"
9#include "dm-space-map.h"
10#include "dm-transaction-manager.h"
11
12#include <linux/export.h>
13#include <linux/device-mapper.h>
14
15#define DM_MSG_PREFIX "array"
16
17/*----------------------------------------------------------------*/
18
19/*
20 * The array is implemented as a fully populated btree, which points to
21 * blocks that contain the packed values. This is more space efficient
22 * than just using a btree since we don't store 1 key per value.
23 */
24struct array_block {
25 __le32 csum;
26 __le32 max_entries;
27 __le32 nr_entries;
28 __le32 value_size;
29 __le64 blocknr; /* Block this node is supposed to live in. */
30} __packed;
31
32/*----------------------------------------------------------------*/
33
34/*
35 * Validator methods. As usual we calculate a checksum, and also write the
36 * block location into the header (paranoia about ssds remapping areas by
37 * mistake).
38 */
39#define CSUM_XOR 595846735
40
41static void array_block_prepare_for_write(const struct dm_block_validator *v,
42 struct dm_block *b,
43 size_t size_of_block)
44{
45 struct array_block *bh_le = dm_block_data(b);
46
47 bh_le->blocknr = cpu_to_le64(dm_block_location(b));
48 bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
49 size_of_block - sizeof(__le32),
50 CSUM_XOR));
51}
52
53static int array_block_check(const struct dm_block_validator *v,
54 struct dm_block *b,
55 size_t size_of_block)
56{
57 struct array_block *bh_le = dm_block_data(b);
58 __le32 csum_disk;
59
60 if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
61 DMERR_LIMIT("%s failed: blocknr %llu != wanted %llu", __func__,
62 (unsigned long long) le64_to_cpu(bh_le->blocknr),
63 (unsigned long long) dm_block_location(b));
64 return -ENOTBLK;
65 }
66
67 csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
68 size_of_block - sizeof(__le32),
69 CSUM_XOR));
70 if (csum_disk != bh_le->csum) {
71 DMERR_LIMIT("%s failed: csum %u != wanted %u", __func__,
72 (unsigned int) le32_to_cpu(csum_disk),
73 (unsigned int) le32_to_cpu(bh_le->csum));
74 return -EILSEQ;
75 }
76
77 return 0;
78}
79
80static const struct dm_block_validator array_validator = {
81 .name = "array",
82 .prepare_for_write = array_block_prepare_for_write,
83 .check = array_block_check
84};
85
86/*----------------------------------------------------------------*/
87
88/*
89 * Functions for manipulating the array blocks.
90 */
91
92/*
93 * Returns a pointer to a value within an array block.
94 *
95 * index - The index into _this_ specific block.
96 */
97static void *element_at(struct dm_array_info *info, struct array_block *ab,
98 unsigned int index)
99{
100 unsigned char *entry = (unsigned char *) (ab + 1);
101
102 entry += index * info->value_type.size;
103
104 return entry;
105}
106
107/*
108 * Utility function that calls one of the value_type methods on every value
109 * in an array block.
110 */
111static void on_entries(struct dm_array_info *info, struct array_block *ab,
112 void (*fn)(void *, const void *, unsigned int))
113{
114 unsigned int nr_entries = le32_to_cpu(ab->nr_entries);
115
116 fn(info->value_type.context, element_at(info, ab, index: 0), nr_entries);
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, fn: 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, fn: 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(tm: info->btree_info.tm, v: &array_validator, result: block);
159 if (r)
160 return r;
161
162 (*ab) = dm_block_data(b: *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 int new_nr)
177{
178 uint32_t nr_entries, delta, i;
179 struct dm_btree_value_type *vt = &info->value_type;
180
181 BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
182 BUG_ON(new_nr < le32_to_cpu(ab->nr_entries));
183
184 nr_entries = le32_to_cpu(ab->nr_entries);
185 delta = new_nr - nr_entries;
186 if (vt->inc)
187 vt->inc(vt->context, value, delta);
188 for (i = nr_entries; i < new_nr; i++)
189 memcpy(element_at(info, ab, i), value, vt->size);
190 ab->nr_entries = cpu_to_le32(new_nr);
191}
192
193/*
194 * Remove some entries from the back of an array block. Every value
195 * removed will be decremented. new_nr must be <= the current number of
196 * entries.
197 */
198static void trim_ablock(struct dm_array_info *info, struct array_block *ab,
199 unsigned int new_nr)
200{
201 uint32_t nr_entries, delta;
202 struct dm_btree_value_type *vt = &info->value_type;
203
204 BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
205 BUG_ON(new_nr > le32_to_cpu(ab->nr_entries));
206
207 nr_entries = le32_to_cpu(ab->nr_entries);
208 delta = nr_entries - new_nr;
209 if (vt->dec)
210 vt->dec(vt->context, element_at(info, ab, index: new_nr - 1), delta);
211 ab->nr_entries = cpu_to_le32(new_nr);
212}
213
214/*
215 * Read locks a block, and coerces it to an array block. The caller must
216 * unlock 'block' when finished.
217 */
218static int get_ablock(struct dm_array_info *info, dm_block_t b,
219 struct dm_block **block, struct array_block **ab)
220{
221 int r;
222
223 r = dm_tm_read_lock(tm: info->btree_info.tm, b, v: &array_validator, result: block);
224 if (r)
225 return r;
226
227 *ab = dm_block_data(b: *block);
228 return 0;
229}
230
231/*
232 * Unlocks an array block.
233 */
234static void unlock_ablock(struct dm_array_info *info, struct dm_block *block)
235{
236 dm_tm_unlock(tm: info->btree_info.tm, b: block);
237}
238
239/*----------------------------------------------------------------*/
240
241/*
242 * Btree manipulation.
243 */
244
245/*
246 * Looks up an array block in the btree, and then read locks it.
247 *
248 * index is the index of the index of the array_block, (ie. the array index
249 * / max_entries).
250 */
251static int lookup_ablock(struct dm_array_info *info, dm_block_t root,
252 unsigned int index, struct dm_block **block,
253 struct array_block **ab)
254{
255 int r;
256 uint64_t key = index;
257 __le64 block_le;
258
259 r = dm_btree_lookup(info: &info->btree_info, root, keys: &key, value_le: &block_le);
260 if (r)
261 return r;
262
263 return get_ablock(info, le64_to_cpu(block_le), block, ab);
264}
265
266/*
267 * Insert an array block into the btree. The block is _not_ unlocked.
268 */
269static int insert_ablock(struct dm_array_info *info, uint64_t index,
270 struct dm_block *block, dm_block_t *root)
271{
272 __le64 block_le = cpu_to_le64(dm_block_location(block));
273
274 __dm_bless_for_disk(block_le);
275 return dm_btree_insert(info: &info->btree_info, root: *root, keys: &index, value: &block_le, new_root: root);
276}
277
278/*----------------------------------------------------------------*/
279
280static int __shadow_ablock(struct dm_array_info *info, dm_block_t b,
281 struct dm_block **block, struct array_block **ab)
282{
283 int inc;
284 int r = dm_tm_shadow_block(tm: info->btree_info.tm, orig: b,
285 v: &array_validator, result: block, inc_children: &inc);
286 if (r)
287 return r;
288
289 *ab = dm_block_data(b: *block);
290 if (inc)
291 inc_ablock_entries(info, ab: *ab);
292
293 return 0;
294}
295
296/*
297 * The shadow op will often be a noop. Only insert if it really
298 * copied data.
299 */
300static int __reinsert_ablock(struct dm_array_info *info, unsigned int index,
301 struct dm_block *block, dm_block_t b,
302 dm_block_t *root)
303{
304 int r = 0;
305
306 if (dm_block_location(b: block) != b) {
307 /*
308 * dm_tm_shadow_block will have already decremented the old
309 * block, but it is still referenced by the btree. We
310 * increment to stop the insert decrementing it below zero
311 * when overwriting the old value.
312 */
313 dm_tm_inc(tm: info->btree_info.tm, b);
314 r = insert_ablock(info, index, block, root);
315 }
316
317 return r;
318}
319
320/*
321 * Looks up an array block in the btree. Then shadows it, and updates the
322 * btree to point to this new shadow. 'root' is an input/output parameter
323 * for both the current root block, and the new one.
324 */
325static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
326 unsigned int index, struct dm_block **block,
327 struct array_block **ab)
328{
329 int r;
330 uint64_t key = index;
331 dm_block_t b;
332 __le64 block_le;
333
334 r = dm_btree_lookup(info: &info->btree_info, root: *root, keys: &key, value_le: &block_le);
335 if (r)
336 return r;
337 b = le64_to_cpu(block_le);
338
339 r = __shadow_ablock(info, b, block, ab);
340 if (r)
341 return r;
342
343 return __reinsert_ablock(info, index, block: *block, b, root);
344}
345
346/*
347 * Allocate an new array block, and fill it with some values.
348 */
349static int insert_new_ablock(struct dm_array_info *info, size_t size_of_block,
350 uint32_t max_entries,
351 unsigned int block_index, uint32_t nr,
352 const void *value, dm_block_t *root)
353{
354 int r;
355 struct dm_block *block;
356 struct array_block *ab;
357
358 r = alloc_ablock(info, size_of_block, max_entries, block: &block, ab: &ab);
359 if (r)
360 return r;
361
362 fill_ablock(info, ab, value, new_nr: nr);
363 r = insert_ablock(info, index: block_index, block, root);
364 unlock_ablock(info, block);
365
366 return r;
367}
368
369static int insert_full_ablocks(struct dm_array_info *info, size_t size_of_block,
370 unsigned int begin_block, unsigned int end_block,
371 unsigned int max_entries, const void *value,
372 dm_block_t *root)
373{
374 int r = 0;
375
376 for (; !r && begin_block != end_block; begin_block++)
377 r = insert_new_ablock(info, size_of_block, max_entries, block_index: begin_block, nr: max_entries, value, root);
378
379 return r;
380}
381
382/*
383 * There are a bunch of functions involved with resizing an array. This
384 * structure holds information that commonly needed by them. Purely here
385 * to reduce parameter count.
386 */
387struct resize {
388 /*
389 * Describes the array.
390 */
391 struct dm_array_info *info;
392
393 /*
394 * The current root of the array. This gets updated.
395 */
396 dm_block_t root;
397
398 /*
399 * Metadata block size. Used to calculate the nr entries in an
400 * array block.
401 */
402 size_t size_of_block;
403
404 /*
405 * Maximum nr entries in an array block.
406 */
407 unsigned int max_entries;
408
409 /*
410 * nr of completely full blocks in the array.
411 *
412 * 'old' refers to before the resize, 'new' after.
413 */
414 unsigned int old_nr_full_blocks, new_nr_full_blocks;
415
416 /*
417 * Number of entries in the final block. 0 iff only full blocks in
418 * the array.
419 */
420 unsigned int old_nr_entries_in_last_block, new_nr_entries_in_last_block;
421
422 /*
423 * The default value used when growing the array.
424 */
425 const void *value;
426};
427
428/*
429 * Removes a consecutive set of array blocks from the btree. The values
430 * in block are decremented as a side effect of the btree remove.
431 *
432 * begin_index - the index of the first array block to remove.
433 * end_index - the one-past-the-end value. ie. this block is not removed.
434 */
435static int drop_blocks(struct resize *resize, unsigned int begin_index,
436 unsigned int end_index)
437{
438 int r;
439
440 while (begin_index != end_index) {
441 uint64_t key = begin_index++;
442
443 r = dm_btree_remove(info: &resize->info->btree_info, root: resize->root,
444 keys: &key, new_root: &resize->root);
445 if (r)
446 return r;
447 }
448
449 return 0;
450}
451
452/*
453 * Calculates how many blocks are needed for the array.
454 */
455static unsigned int total_nr_blocks_needed(unsigned int nr_full_blocks,
456 unsigned int nr_entries_in_last_block)
457{
458 return nr_full_blocks + (nr_entries_in_last_block ? 1 : 0);
459}
460
461/*
462 * Shrink an array.
463 */
464static int shrink(struct resize *resize)
465{
466 int r;
467 unsigned int begin, end;
468 struct dm_block *block;
469 struct array_block *ab;
470
471 /*
472 * Lose some blocks from the back?
473 */
474 if (resize->new_nr_full_blocks < resize->old_nr_full_blocks) {
475 begin = total_nr_blocks_needed(nr_full_blocks: resize->new_nr_full_blocks,
476 nr_entries_in_last_block: resize->new_nr_entries_in_last_block);
477 end = total_nr_blocks_needed(nr_full_blocks: resize->old_nr_full_blocks,
478 nr_entries_in_last_block: resize->old_nr_entries_in_last_block);
479
480 r = drop_blocks(resize, begin_index: begin, end_index: end);
481 if (r)
482 return r;
483 }
484
485 /*
486 * Trim the new tail block
487 */
488 if (resize->new_nr_entries_in_last_block) {
489 r = shadow_ablock(info: resize->info, root: &resize->root,
490 index: resize->new_nr_full_blocks, block: &block, ab: &ab);
491 if (r)
492 return r;
493
494 trim_ablock(info: resize->info, ab, new_nr: resize->new_nr_entries_in_last_block);
495 unlock_ablock(info: resize->info, block);
496 }
497
498 return 0;
499}
500
501/*
502 * Grow an array.
503 */
504static int grow_extend_tail_block(struct resize *resize, uint32_t new_nr_entries)
505{
506 int r;
507 struct dm_block *block;
508 struct array_block *ab;
509
510 r = shadow_ablock(info: resize->info, root: &resize->root,
511 index: resize->old_nr_full_blocks, block: &block, ab: &ab);
512 if (r)
513 return r;
514
515 fill_ablock(info: resize->info, ab, value: resize->value, new_nr: new_nr_entries);
516 unlock_ablock(info: resize->info, block);
517
518 return r;
519}
520
521static int grow_add_tail_block(struct resize *resize)
522{
523 return insert_new_ablock(info: resize->info, size_of_block: resize->size_of_block,
524 max_entries: resize->max_entries,
525 block_index: resize->new_nr_full_blocks,
526 nr: resize->new_nr_entries_in_last_block,
527 value: resize->value, root: &resize->root);
528}
529
530static int grow_needs_more_blocks(struct resize *resize)
531{
532 int r;
533 unsigned int old_nr_blocks = resize->old_nr_full_blocks;
534
535 if (resize->old_nr_entries_in_last_block > 0) {
536 old_nr_blocks++;
537
538 r = grow_extend_tail_block(resize, new_nr_entries: resize->max_entries);
539 if (r)
540 return r;
541 }
542
543 r = insert_full_ablocks(info: resize->info, size_of_block: resize->size_of_block,
544 begin_block: old_nr_blocks,
545 end_block: resize->new_nr_full_blocks,
546 max_entries: resize->max_entries, value: resize->value,
547 root: &resize->root);
548 if (r)
549 return r;
550
551 if (resize->new_nr_entries_in_last_block)
552 r = grow_add_tail_block(resize);
553
554 return r;
555}
556
557static int grow(struct resize *resize)
558{
559 if (resize->new_nr_full_blocks > resize->old_nr_full_blocks)
560 return grow_needs_more_blocks(resize);
561
562 else if (resize->old_nr_entries_in_last_block)
563 return grow_extend_tail_block(resize, new_nr_entries: resize->new_nr_entries_in_last_block);
564
565 else
566 return grow_add_tail_block(resize);
567}
568
569/*----------------------------------------------------------------*/
570
571/*
572 * These are the value_type functions for the btree elements, which point
573 * to array blocks.
574 */
575static void block_inc(void *context, const void *value, unsigned int count)
576{
577 const __le64 *block_le = value;
578 struct dm_array_info *info = context;
579 unsigned int i;
580
581 for (i = 0; i < count; i++, block_le++)
582 dm_tm_inc(tm: 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(tm: info->btree_info.tm, b, result: &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: &block, ab: &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(tm: info->btree_info.tm, b);
622}
623
624static void block_dec(void *context, const void *value, unsigned int count)
625{
626 unsigned int i;
627
628 for (i = 0; i < count; i++, value += sizeof(__le64))
629 __block_dec(context, value);
630}
631
632static int block_equal(void *context, const void *value1, const void *value2)
633{
634 return !memcmp(p: value1, q: value2, size: sizeof(__le64));
635}
636
637/*----------------------------------------------------------------*/
638
639void dm_array_info_init(struct dm_array_info *info,
640 struct dm_transaction_manager *tm,
641 struct dm_btree_value_type *vt)
642{
643 struct dm_btree_value_type *bvt = &info->btree_info.value_type;
644
645 memcpy(&info->value_type, vt, sizeof(info->value_type));
646 info->btree_info.tm = tm;
647 info->btree_info.levels = 1;
648
649 bvt->context = info;
650 bvt->size = sizeof(__le64);
651 bvt->inc = block_inc;
652 bvt->dec = block_dec;
653 bvt->equal = block_equal;
654}
655EXPORT_SYMBOL_GPL(dm_array_info_init);
656
657int dm_array_empty(struct dm_array_info *info, dm_block_t *root)
658{
659 return dm_btree_empty(info: &info->btree_info, root);
660}
661EXPORT_SYMBOL_GPL(dm_array_empty);
662
663static int array_resize(struct dm_array_info *info, dm_block_t root,
664 uint32_t old_size, uint32_t new_size,
665 const void *value, dm_block_t *new_root)
666{
667 int r;
668 struct resize resize;
669
670 if (old_size == new_size) {
671 *new_root = root;
672 return 0;
673 }
674
675 resize.info = info;
676 resize.root = root;
677 resize.size_of_block = dm_bm_block_size(bm: dm_tm_get_bm(tm: info->btree_info.tm));
678 resize.max_entries = calc_max_entries(value_size: info->value_type.size,
679 size_of_block: resize.size_of_block);
680
681 resize.old_nr_full_blocks = old_size / resize.max_entries;
682 resize.old_nr_entries_in_last_block = old_size % resize.max_entries;
683 resize.new_nr_full_blocks = new_size / resize.max_entries;
684 resize.new_nr_entries_in_last_block = new_size % resize.max_entries;
685 resize.value = value;
686
687 r = ((new_size > old_size) ? grow : shrink)(&resize);
688 if (r)
689 return r;
690
691 *new_root = resize.root;
692 return 0;
693}
694
695int dm_array_resize(struct dm_array_info *info, dm_block_t root,
696 uint32_t old_size, uint32_t new_size,
697 const void *value, dm_block_t *new_root)
698 __dm_written_to_disk(value)
699{
700 int r = array_resize(info, root, old_size, new_size, value, new_root);
701
702 __dm_unbless_for_disk(value);
703 return r;
704}
705EXPORT_SYMBOL_GPL(dm_array_resize);
706
707static int populate_ablock_with_values(struct dm_array_info *info, struct array_block *ab,
708 value_fn fn, void *context,
709 unsigned int base, unsigned int new_nr)
710{
711 int r;
712 unsigned int i;
713 struct dm_btree_value_type *vt = &info->value_type;
714
715 BUG_ON(le32_to_cpu(ab->nr_entries));
716 BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
717
718 for (i = 0; i < new_nr; i++) {
719 r = fn(base + i, element_at(info, ab, index: i), context);
720 if (r)
721 return r;
722
723 if (vt->inc)
724 vt->inc(vt->context, element_at(info, ab, index: i), 1);
725 }
726
727 ab->nr_entries = cpu_to_le32(new_nr);
728 return 0;
729}
730
731int dm_array_new(struct dm_array_info *info, dm_block_t *root,
732 uint32_t size, value_fn fn, void *context)
733{
734 int r;
735 struct dm_block *block;
736 struct array_block *ab;
737 unsigned int block_index, end_block, size_of_block, max_entries;
738
739 r = dm_array_empty(info, root);
740 if (r)
741 return r;
742
743 size_of_block = dm_bm_block_size(bm: dm_tm_get_bm(tm: info->btree_info.tm));
744 max_entries = calc_max_entries(value_size: info->value_type.size, size_of_block);
745 end_block = dm_div_up(size, max_entries);
746
747 for (block_index = 0; block_index != end_block; block_index++) {
748 r = alloc_ablock(info, size_of_block, max_entries, block: &block, ab: &ab);
749 if (r)
750 break;
751
752 r = populate_ablock_with_values(info, ab, fn, context,
753 base: block_index * max_entries,
754 min(max_entries, size));
755 if (r) {
756 unlock_ablock(info, block);
757 break;
758 }
759
760 r = insert_ablock(info, index: block_index, block, root);
761 unlock_ablock(info, block);
762 if (r)
763 break;
764
765 size -= max_entries;
766 }
767
768 return r;
769}
770EXPORT_SYMBOL_GPL(dm_array_new);
771
772int dm_array_del(struct dm_array_info *info, dm_block_t root)
773{
774 return dm_btree_del(info: &info->btree_info, root);
775}
776EXPORT_SYMBOL_GPL(dm_array_del);
777
778int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
779 uint32_t index, void *value_le)
780{
781 int r;
782 struct dm_block *block;
783 struct array_block *ab;
784 size_t size_of_block;
785 unsigned int entry, max_entries;
786
787 size_of_block = dm_bm_block_size(bm: dm_tm_get_bm(tm: info->btree_info.tm));
788 max_entries = calc_max_entries(value_size: info->value_type.size, size_of_block);
789
790 r = lookup_ablock(info, root, index: index / max_entries, block: &block, ab: &ab);
791 if (r)
792 return r;
793
794 entry = index % max_entries;
795 if (entry >= le32_to_cpu(ab->nr_entries))
796 r = -ENODATA;
797 else
798 memcpy(value_le, element_at(info, ab, entry),
799 info->value_type.size);
800
801 unlock_ablock(info, block);
802 return r;
803}
804EXPORT_SYMBOL_GPL(dm_array_get_value);
805
806static int array_set_value(struct dm_array_info *info, dm_block_t root,
807 uint32_t index, const void *value, dm_block_t *new_root)
808{
809 int r;
810 struct dm_block *block;
811 struct array_block *ab;
812 size_t size_of_block;
813 unsigned int max_entries;
814 unsigned int entry;
815 void *old_value;
816 struct dm_btree_value_type *vt = &info->value_type;
817
818 size_of_block = dm_bm_block_size(bm: dm_tm_get_bm(tm: info->btree_info.tm));
819 max_entries = calc_max_entries(value_size: info->value_type.size, size_of_block);
820
821 r = shadow_ablock(info, root: &root, index: index / max_entries, block: &block, ab: &ab);
822 if (r)
823 return r;
824 *new_root = root;
825
826 entry = index % max_entries;
827 if (entry >= le32_to_cpu(ab->nr_entries)) {
828 r = -ENODATA;
829 goto out;
830 }
831
832 old_value = element_at(info, ab, index: entry);
833 if (vt->dec &&
834 (!vt->equal || !vt->equal(vt->context, old_value, value))) {
835 vt->dec(vt->context, old_value, 1);
836 if (vt->inc)
837 vt->inc(vt->context, value, 1);
838 }
839
840 memcpy(old_value, value, info->value_type.size);
841
842out:
843 unlock_ablock(info, block);
844 return r;
845}
846
847int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
848 uint32_t index, const void *value, dm_block_t *new_root)
849 __dm_written_to_disk(value)
850{
851 int r;
852
853 r = array_set_value(info, root, index, value, new_root);
854 __dm_unbless_for_disk(value);
855 return r;
856}
857EXPORT_SYMBOL_GPL(dm_array_set_value);
858
859struct walk_info {
860 struct dm_array_info *info;
861 int (*fn)(void *context, uint64_t key, void *leaf);
862 void *context;
863};
864
865static int walk_ablock(void *context, uint64_t *keys, void *leaf)
866{
867 struct walk_info *wi = context;
868
869 int r;
870 unsigned int i;
871 __le64 block_le;
872 unsigned int nr_entries, max_entries;
873 struct dm_block *block;
874 struct array_block *ab;
875
876 memcpy(&block_le, leaf, sizeof(block_le));
877 r = get_ablock(info: wi->info, le64_to_cpu(block_le), block: &block, ab: &ab);
878 if (r)
879 return r;
880
881 max_entries = le32_to_cpu(ab->max_entries);
882 nr_entries = le32_to_cpu(ab->nr_entries);
883 for (i = 0; i < nr_entries; i++) {
884 r = wi->fn(wi->context, keys[0] * max_entries + i,
885 element_at(info: wi->info, ab, index: i));
886
887 if (r)
888 break;
889 }
890
891 unlock_ablock(info: wi->info, block);
892 return r;
893}
894
895int dm_array_walk(struct dm_array_info *info, dm_block_t root,
896 int (*fn)(void *, uint64_t key, void *leaf),
897 void *context)
898{
899 struct walk_info wi;
900
901 wi.info = info;
902 wi.fn = fn;
903 wi.context = context;
904
905 return dm_btree_walk(info: &info->btree_info, root, fn: walk_ablock, context: &wi);
906}
907EXPORT_SYMBOL_GPL(dm_array_walk);
908
909/*----------------------------------------------------------------*/
910
911static int load_ablock(struct dm_array_cursor *c)
912{
913 int r;
914 __le64 value_le;
915 uint64_t key;
916
917 if (c->block)
918 unlock_ablock(info: c->info, block: c->block);
919
920 c->index = 0;
921
922 r = dm_btree_cursor_get_value(c: &c->cursor, key: &key, value_le: &value_le);
923 if (r) {
924 DMERR("dm_btree_cursor_get_value failed");
925 goto out;
926
927 } else {
928 r = get_ablock(info: c->info, le64_to_cpu(value_le), block: &c->block, ab: &c->ab);
929 if (r) {
930 DMERR("get_ablock failed");
931 goto out;
932 }
933 }
934
935 return 0;
936
937out:
938 dm_btree_cursor_end(c: &c->cursor);
939 c->block = NULL;
940 c->ab = NULL;
941 return r;
942}
943
944int dm_array_cursor_begin(struct dm_array_info *info, dm_block_t root,
945 struct dm_array_cursor *c)
946{
947 int r;
948
949 memset(c, 0, sizeof(*c));
950 c->info = info;
951 r = dm_btree_cursor_begin(info: &info->btree_info, root, prefetch_leaves: true, c: &c->cursor);
952 if (r) {
953 DMERR("couldn't create btree cursor");
954 return r;
955 }
956
957 return load_ablock(c);
958}
959EXPORT_SYMBOL_GPL(dm_array_cursor_begin);
960
961void dm_array_cursor_end(struct dm_array_cursor *c)
962{
963 if (c->block)
964 unlock_ablock(info: c->info, block: c->block);
965
966 dm_btree_cursor_end(c: &c->cursor);
967}
968EXPORT_SYMBOL_GPL(dm_array_cursor_end);
969
970int dm_array_cursor_next(struct dm_array_cursor *c)
971{
972 int r;
973
974 if (!c->block)
975 return -ENODATA;
976
977 c->index++;
978
979 if (c->index >= le32_to_cpu(c->ab->nr_entries)) {
980 r = dm_btree_cursor_next(c: &c->cursor);
981 if (r)
982 return r;
983
984 r = load_ablock(c);
985 if (r)
986 return r;
987 }
988
989 return 0;
990}
991EXPORT_SYMBOL_GPL(dm_array_cursor_next);
992
993int dm_array_cursor_skip(struct dm_array_cursor *c, uint32_t count)
994{
995 int r;
996
997 do {
998 uint32_t remaining = le32_to_cpu(c->ab->nr_entries) - c->index;
999
1000 if (count < remaining) {
1001 c->index += count;
1002 return 0;
1003 }
1004
1005 count -= remaining;
1006 c->index += (remaining - 1);
1007 r = dm_array_cursor_next(c);
1008
1009 } while (!r);
1010
1011 return r;
1012}
1013EXPORT_SYMBOL_GPL(dm_array_cursor_skip);
1014
1015void dm_array_cursor_get_value(struct dm_array_cursor *c, void **value_le)
1016{
1017 *value_le = element_at(info: c->info, ab: c->ab, index: c->index);
1018}
1019EXPORT_SYMBOL_GPL(dm_array_cursor_get_value);
1020
1021/*----------------------------------------------------------------*/
1022

source code of linux/drivers/md/persistent-data/dm-array.c