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1/*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-space-map-common.h"
8#include "dm-transaction-manager.h"
9
10#include <linux/bitops.h>
11#include <linux/device-mapper.h>
12
13#define DM_MSG_PREFIX "space map common"
14
15/*----------------------------------------------------------------*/
16
17/*
18 * Index validator.
19 */
20#define INDEX_CSUM_XOR 160478
21
22static void index_prepare_for_write(struct dm_block_validator *v,
23 struct dm_block *b,
24 size_t block_size)
25{
26 struct disk_metadata_index *mi_le = dm_block_data(b);
27
28 mi_le->blocknr = cpu_to_le64(dm_block_location(b));
29 mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
30 block_size - sizeof(__le32),
31 INDEX_CSUM_XOR));
32}
33
34static int index_check(struct dm_block_validator *v,
35 struct dm_block *b,
36 size_t block_size)
37{
38 struct disk_metadata_index *mi_le = dm_block_data(b);
39 __le32 csum_disk;
40
41 if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) {
42 DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu",
43 le64_to_cpu(mi_le->blocknr), dm_block_location(b));
44 return -ENOTBLK;
45 }
46
47 csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
48 block_size - sizeof(__le32),
49 INDEX_CSUM_XOR));
50 if (csum_disk != mi_le->csum) {
51 DMERR_LIMIT("index_check failed: csum %u != wanted %u",
52 le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum));
53 return -EILSEQ;
54 }
55
56 return 0;
57}
58
59static struct dm_block_validator index_validator = {
60 .name = "index",
61 .prepare_for_write = index_prepare_for_write,
62 .check = index_check
63};
64
65/*----------------------------------------------------------------*/
66
67/*
68 * Bitmap validator
69 */
70#define BITMAP_CSUM_XOR 240779
71
72static void bitmap_prepare_for_write(struct dm_block_validator *v,
73 struct dm_block *b,
74 size_t block_size)
75{
76 struct disk_bitmap_header *disk_header = dm_block_data(b);
77
78 disk_header->blocknr = cpu_to_le64(dm_block_location(b));
79 disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
80 block_size - sizeof(__le32),
81 BITMAP_CSUM_XOR));
82}
83
84static int bitmap_check(struct dm_block_validator *v,
85 struct dm_block *b,
86 size_t block_size)
87{
88 struct disk_bitmap_header *disk_header = dm_block_data(b);
89 __le32 csum_disk;
90
91 if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) {
92 DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu",
93 le64_to_cpu(disk_header->blocknr), dm_block_location(b));
94 return -ENOTBLK;
95 }
96
97 csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
98 block_size - sizeof(__le32),
99 BITMAP_CSUM_XOR));
100 if (csum_disk != disk_header->csum) {
101 DMERR_LIMIT("bitmap check failed: csum %u != wanted %u",
102 le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum));
103 return -EILSEQ;
104 }
105
106 return 0;
107}
108
109static struct dm_block_validator dm_sm_bitmap_validator = {
110 .name = "sm_bitmap",
111 .prepare_for_write = bitmap_prepare_for_write,
112 .check = bitmap_check
113};
114
115/*----------------------------------------------------------------*/
116
117#define ENTRIES_PER_WORD 32
118#define ENTRIES_SHIFT 5
119
120static void *dm_bitmap_data(struct dm_block *b)
121{
122 return dm_block_data(b) + sizeof(struct disk_bitmap_header);
123}
124
125#define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL
126
127static unsigned bitmap_word_used(void *addr, unsigned b)
128{
129 __le64 *words_le = addr;
130 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
131
132 uint64_t bits = le64_to_cpu(*w_le);
133 uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH;
134
135 return !(~bits & mask);
136}
137
138static unsigned sm_lookup_bitmap(void *addr, unsigned b)
139{
140 __le64 *words_le = addr;
141 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
142 unsigned hi, lo;
143
144 b = (b & (ENTRIES_PER_WORD - 1)) << 1;
145 hi = !!test_bit_le(b, (void *) w_le);
146 lo = !!test_bit_le(b + 1, (void *) w_le);
147 return (hi << 1) | lo;
148}
149
150static void sm_set_bitmap(void *addr, unsigned b, unsigned val)
151{
152 __le64 *words_le = addr;
153 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
154
155 b = (b & (ENTRIES_PER_WORD - 1)) << 1;
156
157 if (val & 2)
158 __set_bit_le(b, (void *) w_le);
159 else
160 __clear_bit_le(b, (void *) w_le);
161
162 if (val & 1)
163 __set_bit_le(b + 1, (void *) w_le);
164 else
165 __clear_bit_le(b + 1, (void *) w_le);
166}
167
168static int sm_find_free(void *addr, unsigned begin, unsigned end,
169 unsigned *result)
170{
171 while (begin < end) {
172 if (!(begin & (ENTRIES_PER_WORD - 1)) &&
173 bitmap_word_used(addr, begin)) {
174 begin += ENTRIES_PER_WORD;
175 continue;
176 }
177
178 if (!sm_lookup_bitmap(addr, begin)) {
179 *result = begin;
180 return 0;
181 }
182
183 begin++;
184 }
185
186 return -ENOSPC;
187}
188
189/*----------------------------------------------------------------*/
190
191static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm)
192{
193 ll->tm = tm;
194
195 ll->bitmap_info.tm = tm;
196 ll->bitmap_info.levels = 1;
197
198 /*
199 * Because the new bitmap blocks are created via a shadow
200 * operation, the old entry has already had its reference count
201 * decremented and we don't need the btree to do any bookkeeping.
202 */
203 ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry);
204 ll->bitmap_info.value_type.inc = NULL;
205 ll->bitmap_info.value_type.dec = NULL;
206 ll->bitmap_info.value_type.equal = NULL;
207
208 ll->ref_count_info.tm = tm;
209 ll->ref_count_info.levels = 1;
210 ll->ref_count_info.value_type.size = sizeof(uint32_t);
211 ll->ref_count_info.value_type.inc = NULL;
212 ll->ref_count_info.value_type.dec = NULL;
213 ll->ref_count_info.value_type.equal = NULL;
214
215 ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm));
216
217 if (ll->block_size > (1 << 30)) {
218 DMERR("block size too big to hold bitmaps");
219 return -EINVAL;
220 }
221
222 ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) *
223 ENTRIES_PER_BYTE;
224 ll->nr_blocks = 0;
225 ll->bitmap_root = 0;
226 ll->ref_count_root = 0;
227 ll->bitmap_index_changed = false;
228
229 return 0;
230}
231
232int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
233{
234 int r;
235 dm_block_t i, nr_blocks, nr_indexes;
236 unsigned old_blocks, blocks;
237
238 nr_blocks = ll->nr_blocks + extra_blocks;
239 old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block);
240 blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block);
241
242 nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block);
243 if (nr_indexes > ll->max_entries(ll)) {
244 DMERR("space map too large");
245 return -EINVAL;
246 }
247
248 /*
249 * We need to set this before the dm_tm_new_block() call below.
250 */
251 ll->nr_blocks = nr_blocks;
252 for (i = old_blocks; i < blocks; i++) {
253 struct dm_block *b;
254 struct disk_index_entry idx;
255
256 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
257 if (r < 0)
258 return r;
259
260 idx.blocknr = cpu_to_le64(dm_block_location(b));
261
262 dm_tm_unlock(ll->tm, b);
263
264 idx.nr_free = cpu_to_le32(ll->entries_per_block);
265 idx.none_free_before = 0;
266
267 r = ll->save_ie(ll, i, &idx);
268 if (r < 0)
269 return r;
270 }
271
272 return 0;
273}
274
275int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result)
276{
277 int r;
278 dm_block_t index = b;
279 struct disk_index_entry ie_disk;
280 struct dm_block *blk;
281
282 b = do_div(index, ll->entries_per_block);
283 r = ll->load_ie(ll, index, &ie_disk);
284 if (r < 0)
285 return r;
286
287 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
288 &dm_sm_bitmap_validator, &blk);
289 if (r < 0)
290 return r;
291
292 *result = sm_lookup_bitmap(dm_bitmap_data(blk), b);
293
294 dm_tm_unlock(ll->tm, blk);
295
296 return 0;
297}
298
299static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b,
300 uint32_t *result)
301{
302 __le32 le_rc;
303 int r;
304
305 r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc);
306 if (r < 0)
307 return r;
308
309 *result = le32_to_cpu(le_rc);
310
311 return r;
312}
313
314int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result)
315{
316 int r = sm_ll_lookup_bitmap(ll, b, result);
317
318 if (r)
319 return r;
320
321 if (*result != 3)
322 return r;
323
324 return sm_ll_lookup_big_ref_count(ll, b, result);
325}
326
327int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
328 dm_block_t end, dm_block_t *result)
329{
330 int r;
331 struct disk_index_entry ie_disk;
332 dm_block_t i, index_begin = begin;
333 dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block);
334
335 /*
336 * FIXME: Use shifts
337 */
338 begin = do_div(index_begin, ll->entries_per_block);
339 end = do_div(end, ll->entries_per_block);
340
341 for (i = index_begin; i < index_end; i++, begin = 0) {
342 struct dm_block *blk;
343 unsigned position;
344 uint32_t bit_end;
345
346 r = ll->load_ie(ll, i, &ie_disk);
347 if (r < 0)
348 return r;
349
350 if (le32_to_cpu(ie_disk.nr_free) == 0)
351 continue;
352
353 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
354 &dm_sm_bitmap_validator, &blk);
355 if (r < 0)
356 return r;
357
358 bit_end = (i == index_end - 1) ? end : ll->entries_per_block;
359
360 r = sm_find_free(dm_bitmap_data(blk),
361 max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)),
362 bit_end, &position);
363 if (r == -ENOSPC) {
364 /*
365 * This might happen because we started searching
366 * part way through the bitmap.
367 */
368 dm_tm_unlock(ll->tm, blk);
369 continue;
370
371 } else if (r < 0) {
372 dm_tm_unlock(ll->tm, blk);
373 return r;
374 }
375
376 dm_tm_unlock(ll->tm, blk);
377
378 *result = i * ll->entries_per_block + (dm_block_t) position;
379 return 0;
380 }
381
382 return -ENOSPC;
383}
384
385static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b,
386 int (*mutator)(void *context, uint32_t old, uint32_t *new),
387 void *context, enum allocation_event *ev)
388{
389 int r;
390 uint32_t bit, old, ref_count;
391 struct dm_block *nb;
392 dm_block_t index = b;
393 struct disk_index_entry ie_disk;
394 void *bm_le;
395 int inc;
396
397 bit = do_div(index, ll->entries_per_block);
398 r = ll->load_ie(ll, index, &ie_disk);
399 if (r < 0)
400 return r;
401
402 r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr),
403 &dm_sm_bitmap_validator, &nb, &inc);
404 if (r < 0) {
405 DMERR("dm_tm_shadow_block() failed");
406 return r;
407 }
408 ie_disk.blocknr = cpu_to_le64(dm_block_location(nb));
409
410 bm_le = dm_bitmap_data(nb);
411 old = sm_lookup_bitmap(bm_le, bit);
412
413 if (old > 2) {
414 r = sm_ll_lookup_big_ref_count(ll, b, &old);
415 if (r < 0) {
416 dm_tm_unlock(ll->tm, nb);
417 return r;
418 }
419 }
420
421 r = mutator(context, old, &ref_count);
422 if (r) {
423 dm_tm_unlock(ll->tm, nb);
424 return r;
425 }
426
427 if (ref_count <= 2) {
428 sm_set_bitmap(bm_le, bit, ref_count);
429
430 dm_tm_unlock(ll->tm, nb);
431
432 if (old > 2) {
433 r = dm_btree_remove(&ll->ref_count_info,
434 ll->ref_count_root,
435 &b, &ll->ref_count_root);
436 if (r)
437 return r;
438 }
439
440 } else {
441 __le32 le_rc = cpu_to_le32(ref_count);
442
443 sm_set_bitmap(bm_le, bit, 3);
444 dm_tm_unlock(ll->tm, nb);
445
446 __dm_bless_for_disk(&le_rc);
447 r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root,
448 &b, &le_rc, &ll->ref_count_root);
449 if (r < 0) {
450 DMERR("ref count insert failed");
451 return r;
452 }
453 }
454
455 if (ref_count && !old) {
456 *ev = SM_ALLOC;
457 ll->nr_allocated++;
458 le32_add_cpu(&ie_disk.nr_free, -1);
459 if (le32_to_cpu(ie_disk.none_free_before) == bit)
460 ie_disk.none_free_before = cpu_to_le32(bit + 1);
461
462 } else if (old && !ref_count) {
463 *ev = SM_FREE;
464 ll->nr_allocated--;
465 le32_add_cpu(&ie_disk.nr_free, 1);
466 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit));
467 } else
468 *ev = SM_NONE;
469
470 return ll->save_ie(ll, index, &ie_disk);
471}
472
473static int set_ref_count(void *context, uint32_t old, uint32_t *new)
474{
475 *new = *((uint32_t *) context);
476 return 0;
477}
478
479int sm_ll_insert(struct ll_disk *ll, dm_block_t b,
480 uint32_t ref_count, enum allocation_event *ev)
481{
482 return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev);
483}
484
485static int inc_ref_count(void *context, uint32_t old, uint32_t *new)
486{
487 *new = old + 1;
488 return 0;
489}
490
491int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
492{
493 return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev);
494}
495
496static int dec_ref_count(void *context, uint32_t old, uint32_t *new)
497{
498 if (!old) {
499 DMERR_LIMIT("unable to decrement a reference count below 0");
500 return -EINVAL;
501 }
502
503 *new = old - 1;
504 return 0;
505}
506
507int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
508{
509 return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev);
510}
511
512int sm_ll_commit(struct ll_disk *ll)
513{
514 int r = 0;
515
516 if (ll->bitmap_index_changed) {
517 r = ll->commit(ll);
518 if (!r)
519 ll->bitmap_index_changed = false;
520 }
521
522 return r;
523}
524
525/*----------------------------------------------------------------*/
526
527static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index,
528 struct disk_index_entry *ie)
529{
530 memcpy(ie, ll->mi_le.index + index, sizeof(*ie));
531 return 0;
532}
533
534static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index,
535 struct disk_index_entry *ie)
536{
537 ll->bitmap_index_changed = true;
538 memcpy(ll->mi_le.index + index, ie, sizeof(*ie));
539 return 0;
540}
541
542static int metadata_ll_init_index(struct ll_disk *ll)
543{
544 int r;
545 struct dm_block *b;
546
547 r = dm_tm_new_block(ll->tm, &index_validator, &b);
548 if (r < 0)
549 return r;
550
551 ll->bitmap_root = dm_block_location(b);
552
553 dm_tm_unlock(ll->tm, b);
554
555 return 0;
556}
557
558static int metadata_ll_open(struct ll_disk *ll)
559{
560 int r;
561 struct dm_block *block;
562
563 r = dm_tm_read_lock(ll->tm, ll->bitmap_root,
564 &index_validator, &block);
565 if (r)
566 return r;
567
568 memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le));
569 dm_tm_unlock(ll->tm, block);
570
571 return 0;
572}
573
574static dm_block_t metadata_ll_max_entries(struct ll_disk *ll)
575{
576 return MAX_METADATA_BITMAPS;
577}
578
579static int metadata_ll_commit(struct ll_disk *ll)
580{
581 int r, inc;
582 struct dm_block *b;
583
584 r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc);
585 if (r)
586 return r;
587
588 memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
589 ll->bitmap_root = dm_block_location(b);
590
591 dm_tm_unlock(ll->tm, b);
592
593 return 0;
594}
595
596int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm)
597{
598 int r;
599
600 r = sm_ll_init(ll, tm);
601 if (r < 0)
602 return r;
603
604 ll->load_ie = metadata_ll_load_ie;
605 ll->save_ie = metadata_ll_save_ie;
606 ll->init_index = metadata_ll_init_index;
607 ll->open_index = metadata_ll_open;
608 ll->max_entries = metadata_ll_max_entries;
609 ll->commit = metadata_ll_commit;
610
611 ll->nr_blocks = 0;
612 ll->nr_allocated = 0;
613
614 r = ll->init_index(ll);
615 if (r < 0)
616 return r;
617
618 r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
619 if (r < 0)
620 return r;
621
622 return 0;
623}
624
625int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
626 void *root_le, size_t len)
627{
628 int r;
629 struct disk_sm_root smr;
630
631 if (len < sizeof(struct disk_sm_root)) {
632 DMERR("sm_metadata root too small");
633 return -ENOMEM;
634 }
635
636 /*
637 * We don't know the alignment of the root_le buffer, so need to
638 * copy into a new structure.
639 */
640 memcpy(&smr, root_le, sizeof(smr));
641
642 r = sm_ll_init(ll, tm);
643 if (r < 0)
644 return r;
645
646 ll->load_ie = metadata_ll_load_ie;
647 ll->save_ie = metadata_ll_save_ie;
648 ll->init_index = metadata_ll_init_index;
649 ll->open_index = metadata_ll_open;
650 ll->max_entries = metadata_ll_max_entries;
651 ll->commit = metadata_ll_commit;
652
653 ll->nr_blocks = le64_to_cpu(smr.nr_blocks);
654 ll->nr_allocated = le64_to_cpu(smr.nr_allocated);
655 ll->bitmap_root = le64_to_cpu(smr.bitmap_root);
656 ll->ref_count_root = le64_to_cpu(smr.ref_count_root);
657
658 return ll->open_index(ll);
659}
660
661/*----------------------------------------------------------------*/
662
663static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index,
664 struct disk_index_entry *ie)
665{
666 return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie);
667}
668
669static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index,
670 struct disk_index_entry *ie)
671{
672 __dm_bless_for_disk(ie);
673 return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root,
674 &index, ie, &ll->bitmap_root);
675}
676
677static int disk_ll_init_index(struct ll_disk *ll)
678{
679 return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root);
680}
681
682static int disk_ll_open(struct ll_disk *ll)
683{
684 /* nothing to do */
685 return 0;
686}
687
688static dm_block_t disk_ll_max_entries(struct ll_disk *ll)
689{
690 return -1ULL;
691}
692
693static int disk_ll_commit(struct ll_disk *ll)
694{
695 return 0;
696}
697
698int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm)
699{
700 int r;
701
702 r = sm_ll_init(ll, tm);
703 if (r < 0)
704 return r;
705
706 ll->load_ie = disk_ll_load_ie;
707 ll->save_ie = disk_ll_save_ie;
708 ll->init_index = disk_ll_init_index;
709 ll->open_index = disk_ll_open;
710 ll->max_entries = disk_ll_max_entries;
711 ll->commit = disk_ll_commit;
712
713 ll->nr_blocks = 0;
714 ll->nr_allocated = 0;
715
716 r = ll->init_index(ll);
717 if (r < 0)
718 return r;
719
720 r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
721 if (r < 0)
722 return r;
723
724 return 0;
725}
726
727int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
728 void *root_le, size_t len)
729{
730 int r;
731 struct disk_sm_root *smr = root_le;
732
733 if (len < sizeof(struct disk_sm_root)) {
734 DMERR("sm_metadata root too small");
735 return -ENOMEM;
736 }
737
738 r = sm_ll_init(ll, tm);
739 if (r < 0)
740 return r;
741
742 ll->load_ie = disk_ll_load_ie;
743 ll->save_ie = disk_ll_save_ie;
744 ll->init_index = disk_ll_init_index;
745 ll->open_index = disk_ll_open;
746 ll->max_entries = disk_ll_max_entries;
747 ll->commit = disk_ll_commit;
748
749 ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
750 ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
751 ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
752 ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
753
754 return ll->open_index(ll);
755}
756
757/*----------------------------------------------------------------*/