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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2019 Arrikto, Inc. All Rights Reserved.
4 */
5
6#include <linux/mm.h>
7#include <linux/err.h>
8#include <linux/slab.h>
9#include <linux/rwsem.h>
10#include <linux/bitops.h>
11#include <linux/bitmap.h>
12#include <linux/device-mapper.h>
13
14#include "persistent-data/dm-bitset.h"
15#include "persistent-data/dm-space-map.h"
16#include "persistent-data/dm-block-manager.h"
17#include "persistent-data/dm-transaction-manager.h"
18
19#include "dm-clone-metadata.h"
20
21#define DM_MSG_PREFIX "clone metadata"
22
23#define SUPERBLOCK_LOCATION 0
24#define SUPERBLOCK_MAGIC 0x8af27f64
25#define SUPERBLOCK_CSUM_XOR 257649492
26
27#define DM_CLONE_MAX_CONCURRENT_LOCKS 5
28
29#define UUID_LEN 16
30
31/* Min and max dm-clone metadata versions supported */
32#define DM_CLONE_MIN_METADATA_VERSION 1
33#define DM_CLONE_MAX_METADATA_VERSION 1
34
35/*
36 * On-disk metadata layout
37 */
38struct superblock_disk {
39 __le32 csum;
40 __le32 flags;
41 __le64 blocknr;
42
43 __u8 uuid[UUID_LEN];
44 __le64 magic;
45 __le32 version;
46
47 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
48
49 __le64 region_size;
50 __le64 target_size;
51
52 __le64 bitset_root;
53} __packed;
54
55/*
56 * Region and Dirty bitmaps.
57 *
58 * dm-clone logically splits the source and destination devices in regions of
59 * fixed size. The destination device's regions are gradually hydrated, i.e.,
60 * we copy (clone) the source's regions to the destination device. Eventually,
61 * all regions will get hydrated and all I/O will be served from the
62 * destination device.
63 *
64 * We maintain an on-disk bitmap which tracks the state of each of the
65 * destination device's regions, i.e., whether they are hydrated or not.
66 *
67 * To save constantly doing look ups on disk we keep an in core copy of the
68 * on-disk bitmap, the region_map.
69 *
70 * In order to track which regions are hydrated during a metadata transaction,
71 * we use a second set of bitmaps, the dmap (dirty bitmap), which includes two
72 * bitmaps, namely dirty_regions and dirty_words. The dirty_regions bitmap
73 * tracks the regions that got hydrated during the current metadata
74 * transaction. The dirty_words bitmap tracks the dirty words, i.e. longs, of
75 * the dirty_regions bitmap.
76 *
77 * This allows us to precisely track the regions that were hydrated during the
78 * current metadata transaction and update the metadata accordingly, when we
79 * commit the current transaction. This is important because dm-clone should
80 * only commit the metadata of regions that were properly flushed to the
81 * destination device beforehand. Otherwise, in case of a crash, we could end
82 * up with a corrupted dm-clone device.
83 *
84 * When a region finishes hydrating dm-clone calls
85 * dm_clone_set_region_hydrated(), or for discard requests
86 * dm_clone_cond_set_range(), which sets the corresponding bits in region_map
87 * and dmap.
88 *
89 * During a metadata commit we scan dmap->dirty_words and dmap->dirty_regions
90 * and update the on-disk metadata accordingly. Thus, we don't have to flush to
91 * disk the whole region_map. We can just flush the dirty region_map bits.
92 *
93 * We use the helper dmap->dirty_words bitmap, which is smaller than the
94 * original region_map, to reduce the amount of memory accesses during a
95 * metadata commit. Moreover, as dm-bitset also accesses the on-disk bitmap in
96 * 64-bit word granularity, the dirty_words bitmap helps us avoid useless disk
97 * accesses.
98 *
99 * We could update directly the on-disk bitmap, when dm-clone calls either
100 * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), buts this
101 * inserts significant metadata I/O overhead in dm-clone's I/O path. Also, as
102 * these two functions don't block, we can call them in interrupt context,
103 * e.g., in a hooked overwrite bio's completion routine, and further reduce the
104 * I/O completion latency.
105 *
106 * We maintain two dirty bitmap sets. During a metadata commit we atomically
107 * swap the currently used dmap with the unused one. This allows the metadata
108 * update functions to run concurrently with an ongoing commit.
109 */
110struct dirty_map {
111 unsigned long *dirty_words;
112 unsigned long *dirty_regions;
113 unsigned int changed;
114};
115
116struct dm_clone_metadata {
117 /* The metadata block device */
118 struct block_device *bdev;
119
120 sector_t target_size;
121 sector_t region_size;
122 unsigned long nr_regions;
123 unsigned long nr_words;
124
125 /* Spinlock protecting the region and dirty bitmaps. */
126 spinlock_t bitmap_lock;
127 struct dirty_map dmap[2];
128 struct dirty_map *current_dmap;
129
130 /* Protected by lock */
131 struct dirty_map *committing_dmap;
132
133 /*
134 * In core copy of the on-disk bitmap to save constantly doing look ups
135 * on disk.
136 */
137 unsigned long *region_map;
138
139 /* Protected by bitmap_lock */
140 unsigned int read_only;
141
142 struct dm_block_manager *bm;
143 struct dm_space_map *sm;
144 struct dm_transaction_manager *tm;
145
146 struct rw_semaphore lock;
147
148 struct dm_disk_bitset bitset_info;
149 dm_block_t bitset_root;
150
151 /*
152 * Reading the space map root can fail, so we read it into this
153 * buffer before the superblock is locked and updated.
154 */
155 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
156
157 bool hydration_done:1;
158 bool fail_io:1;
159};
160
161/*---------------------------------------------------------------------------*/
162
163/*
164 * Superblock validation.
165 */
166static void sb_prepare_for_write(const struct dm_block_validator *v,
167 struct dm_block *b, size_t sb_block_size)
168{
169 struct superblock_disk *sb;
170 u32 csum;
171
172 sb = dm_block_data(b);
173 sb->blocknr = cpu_to_le64(dm_block_location(b));
174
175 csum = dm_bm_checksum(&sb->flags, sb_block_size - sizeof(__le32),
176 SUPERBLOCK_CSUM_XOR);
177 sb->csum = cpu_to_le32(csum);
178}
179
180static int sb_check(const struct dm_block_validator *v, struct dm_block *b,
181 size_t sb_block_size)
182{
183 struct superblock_disk *sb;
184 u32 csum, metadata_version;
185
186 sb = dm_block_data(b);
187
188 if (dm_block_location(b) != le64_to_cpu(sb->blocknr)) {
189 DMERR("Superblock check failed: blocknr %llu, expected %llu",
190 le64_to_cpu(sb->blocknr),
191 (unsigned long long)dm_block_location(b));
192 return -ENOTBLK;
193 }
194
195 if (le64_to_cpu(sb->magic) != SUPERBLOCK_MAGIC) {
196 DMERR("Superblock check failed: magic %llu, expected %llu",
197 le64_to_cpu(sb->magic),
198 (unsigned long long)SUPERBLOCK_MAGIC);
199 return -EILSEQ;
200 }
201
202 csum = dm_bm_checksum(&sb->flags, sb_block_size - sizeof(__le32),
203 SUPERBLOCK_CSUM_XOR);
204 if (sb->csum != cpu_to_le32(csum)) {
205 DMERR("Superblock check failed: checksum %u, expected %u",
206 csum, le32_to_cpu(sb->csum));
207 return -EILSEQ;
208 }
209
210 /* Check metadata version */
211 metadata_version = le32_to_cpu(sb->version);
212 if (metadata_version < DM_CLONE_MIN_METADATA_VERSION ||
213 metadata_version > DM_CLONE_MAX_METADATA_VERSION) {
214 DMERR("Clone metadata version %u found, but only versions between %u and %u supported.",
215 metadata_version, DM_CLONE_MIN_METADATA_VERSION,
216 DM_CLONE_MAX_METADATA_VERSION);
217 return -EINVAL;
218 }
219
220 return 0;
221}
222
223static const struct dm_block_validator sb_validator = {
224 .name = "superblock",
225 .prepare_for_write = sb_prepare_for_write,
226 .check = sb_check
227};
228
229/*
230 * Check if the superblock is formatted or not. We consider the superblock to
231 * be formatted in case we find non-zero bytes in it.
232 */
233static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *formatted)
234{
235 int r;
236 unsigned int i, nr_words;
237 struct dm_block *sblock;
238 __le64 *data_le, zero = cpu_to_le64(0);
239
240 /*
241 * We don't use a validator here because the superblock could be all
242 * zeroes.
243 */
244 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &sblock);
245 if (r) {
246 DMERR("Failed to read_lock superblock");
247 return r;
248 }
249
250 data_le = dm_block_data(sblock);
251 *formatted = false;
252
253 /* This assumes that the block size is a multiple of 8 bytes */
254 BUG_ON(dm_bm_block_size(bm) % sizeof(__le64));
255 nr_words = dm_bm_block_size(bm) / sizeof(__le64);
256 for (i = 0; i < nr_words; i++) {
257 if (data_le[i] != zero) {
258 *formatted = true;
259 break;
260 }
261 }
262
263 dm_bm_unlock(sblock);
264
265 return 0;
266}
267
268/*---------------------------------------------------------------------------*/
269
270/*
271 * Low-level metadata handling.
272 */
273static inline int superblock_read_lock(struct dm_clone_metadata *cmd,
274 struct dm_block **sblock)
275{
276 return dm_bm_read_lock(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock);
277}
278
279static inline int superblock_write_lock_zero(struct dm_clone_metadata *cmd,
280 struct dm_block **sblock)
281{
282 return dm_bm_write_lock_zero(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock);
283}
284
285static int __copy_sm_root(struct dm_clone_metadata *cmd)
286{
287 int r;
288 size_t root_size;
289
290 r = dm_sm_root_size(cmd->sm, &root_size);
291 if (r)
292 return r;
293
294 return dm_sm_copy_root(cmd->sm, &cmd->metadata_space_map_root, root_size);
295}
296
297/* Save dm-clone metadata in superblock */
298static void __prepare_superblock(struct dm_clone_metadata *cmd,
299 struct superblock_disk *sb)
300{
301 sb->flags = cpu_to_le32(0UL);
302
303 /* FIXME: UUID is currently unused */
304 memset(sb->uuid, 0, sizeof(sb->uuid));
305
306 sb->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
307 sb->version = cpu_to_le32(DM_CLONE_MAX_METADATA_VERSION);
308
309 /* Save the metadata space_map root */
310 memcpy(&sb->metadata_space_map_root, &cmd->metadata_space_map_root,
311 sizeof(cmd->metadata_space_map_root));
312
313 sb->region_size = cpu_to_le64(cmd->region_size);
314 sb->target_size = cpu_to_le64(cmd->target_size);
315 sb->bitset_root = cpu_to_le64(cmd->bitset_root);
316}
317
318static int __open_metadata(struct dm_clone_metadata *cmd)
319{
320 int r;
321 struct dm_block *sblock;
322 struct superblock_disk *sb;
323
324 r = superblock_read_lock(cmd, &sblock);
325
326 if (r) {
327 DMERR("Failed to read_lock superblock");
328 return r;
329 }
330
331 sb = dm_block_data(sblock);
332
333 /* Verify that target_size and region_size haven't changed. */
334 if (cmd->region_size != le64_to_cpu(sb->region_size) ||
335 cmd->target_size != le64_to_cpu(sb->target_size)) {
336 DMERR("Region and/or target size don't match the ones in metadata");
337 r = -EINVAL;
338 goto out_with_lock;
339 }
340
341 r = dm_tm_open_with_sm(cmd->bm, SUPERBLOCK_LOCATION,
342 sb->metadata_space_map_root,
343 sizeof(sb->metadata_space_map_root),
344 &cmd->tm, &cmd->sm);
345
346 if (r) {
347 DMERR("dm_tm_open_with_sm failed");
348 goto out_with_lock;
349 }
350
351 dm_disk_bitset_init(cmd->tm, &cmd->bitset_info);
352 cmd->bitset_root = le64_to_cpu(sb->bitset_root);
353
354out_with_lock:
355 dm_bm_unlock(sblock);
356
357 return r;
358}
359
360static int __format_metadata(struct dm_clone_metadata *cmd)
361{
362 int r;
363 struct dm_block *sblock;
364 struct superblock_disk *sb;
365
366 r = dm_tm_create_with_sm(cmd->bm, SUPERBLOCK_LOCATION, &cmd->tm, &cmd->sm);
367 if (r) {
368 DMERR("Failed to create transaction manager");
369 return r;
370 }
371
372 dm_disk_bitset_init(cmd->tm, &cmd->bitset_info);
373
374 r = dm_bitset_empty(&cmd->bitset_info, &cmd->bitset_root);
375 if (r) {
376 DMERR("Failed to create empty on-disk bitset");
377 goto err_with_tm;
378 }
379
380 r = dm_bitset_resize(&cmd->bitset_info, cmd->bitset_root, 0,
381 cmd->nr_regions, false, &cmd->bitset_root);
382 if (r) {
383 DMERR("Failed to resize on-disk bitset to %lu entries", cmd->nr_regions);
384 goto err_with_tm;
385 }
386
387 /* Flush to disk all blocks, except the superblock */
388 r = dm_tm_pre_commit(cmd->tm);
389 if (r) {
390 DMERR("dm_tm_pre_commit failed");
391 goto err_with_tm;
392 }
393
394 r = __copy_sm_root(cmd);
395 if (r) {
396 DMERR("__copy_sm_root failed");
397 goto err_with_tm;
398 }
399
400 r = superblock_write_lock_zero(cmd, &sblock);
401 if (r) {
402 DMERR("Failed to write_lock superblock");
403 goto err_with_tm;
404 }
405
406 sb = dm_block_data(sblock);
407 __prepare_superblock(cmd, sb);
408 r = dm_tm_commit(cmd->tm, sblock);
409 if (r) {
410 DMERR("Failed to commit superblock");
411 goto err_with_tm;
412 }
413
414 return 0;
415
416err_with_tm:
417 dm_sm_destroy(cmd->sm);
418 dm_tm_destroy(cmd->tm);
419
420 return r;
421}
422
423static int __open_or_format_metadata(struct dm_clone_metadata *cmd, bool may_format_device)
424{
425 int r;
426 bool formatted = false;
427
428 r = __superblock_all_zeroes(cmd->bm, &formatted);
429 if (r)
430 return r;
431
432 if (!formatted)
433 return may_format_device ? __format_metadata(cmd) : -EPERM;
434
435 return __open_metadata(cmd);
436}
437
438static int __create_persistent_data_structures(struct dm_clone_metadata *cmd,
439 bool may_format_device)
440{
441 int r;
442
443 /* Create block manager */
444 cmd->bm = dm_block_manager_create(cmd->bdev,
445 DM_CLONE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
446 DM_CLONE_MAX_CONCURRENT_LOCKS);
447 if (IS_ERR(cmd->bm)) {
448 DMERR("Failed to create block manager");
449 return PTR_ERR(cmd->bm);
450 }
451
452 r = __open_or_format_metadata(cmd, may_format_device);
453 if (r)
454 dm_block_manager_destroy(cmd->bm);
455
456 return r;
457}
458
459static void __destroy_persistent_data_structures(struct dm_clone_metadata *cmd)
460{
461 dm_sm_destroy(cmd->sm);
462 dm_tm_destroy(cmd->tm);
463 dm_block_manager_destroy(cmd->bm);
464}
465
466/*---------------------------------------------------------------------------*/
467
468static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words,
469 unsigned long nr_regions)
470{
471 dmap->changed = 0;
472
473 dmap->dirty_words = kvzalloc(bitmap_size(nr_words), GFP_KERNEL);
474 if (!dmap->dirty_words)
475 return -ENOMEM;
476
477 dmap->dirty_regions = kvzalloc(bitmap_size(nr_regions), GFP_KERNEL);
478 if (!dmap->dirty_regions) {
479 kvfree(dmap->dirty_words);
480 return -ENOMEM;
481 }
482
483 return 0;
484}
485
486static void __dirty_map_exit(struct dirty_map *dmap)
487{
488 kvfree(dmap->dirty_words);
489 kvfree(dmap->dirty_regions);
490}
491
492static int dirty_map_init(struct dm_clone_metadata *cmd)
493{
494 if (__dirty_map_init(&cmd->dmap[0], cmd->nr_words, cmd->nr_regions)) {
495 DMERR("Failed to allocate dirty bitmap");
496 return -ENOMEM;
497 }
498
499 if (__dirty_map_init(&cmd->dmap[1], cmd->nr_words, cmd->nr_regions)) {
500 DMERR("Failed to allocate dirty bitmap");
501 __dirty_map_exit(&cmd->dmap[0]);
502 return -ENOMEM;
503 }
504
505 cmd->current_dmap = &cmd->dmap[0];
506 cmd->committing_dmap = NULL;
507
508 return 0;
509}
510
511static void dirty_map_exit(struct dm_clone_metadata *cmd)
512{
513 __dirty_map_exit(&cmd->dmap[0]);
514 __dirty_map_exit(&cmd->dmap[1]);
515}
516
517static int __load_bitset_in_core(struct dm_clone_metadata *cmd)
518{
519 int r;
520 unsigned long i;
521 struct dm_bitset_cursor c;
522
523 /* Flush bitset cache */
524 r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root);
525 if (r)
526 return r;
527
528 r = dm_bitset_cursor_begin(&cmd->bitset_info, cmd->bitset_root, cmd->nr_regions, &c);
529 if (r)
530 return r;
531
532 for (i = 0; ; i++) {
533 __assign_bit(i, cmd->region_map, dm_bitset_cursor_get_value(&c));
534
535 if (i >= (cmd->nr_regions - 1))
536 break;
537
538 r = dm_bitset_cursor_next(&c);
539
540 if (r)
541 break;
542 }
543
544 dm_bitset_cursor_end(&c);
545
546 return r;
547}
548
549struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev,
550 sector_t target_size,
551 sector_t region_size)
552{
553 int r;
554 struct dm_clone_metadata *cmd;
555
556 cmd = kzalloc_obj(*cmd);
557 if (!cmd) {
558 DMERR("Failed to allocate memory for dm-clone metadata");
559 return ERR_PTR(-ENOMEM);
560 }
561
562 cmd->bdev = bdev;
563 cmd->target_size = target_size;
564 cmd->region_size = region_size;
565 cmd->nr_regions = dm_sector_div_up(cmd->target_size, cmd->region_size);
566 cmd->nr_words = BITS_TO_LONGS(cmd->nr_regions);
567
568 init_rwsem(&cmd->lock);
569 spin_lock_init(&cmd->bitmap_lock);
570 cmd->read_only = 0;
571 cmd->fail_io = false;
572 cmd->hydration_done = false;
573
574 cmd->region_map = kvmalloc(bitmap_size(cmd->nr_regions), GFP_KERNEL);
575 if (!cmd->region_map) {
576 DMERR("Failed to allocate memory for region bitmap");
577 r = -ENOMEM;
578 goto out_with_md;
579 }
580
581 r = __create_persistent_data_structures(cmd, true);
582 if (r)
583 goto out_with_region_map;
584
585 r = __load_bitset_in_core(cmd);
586 if (r) {
587 DMERR("Failed to load on-disk region map");
588 goto out_with_pds;
589 }
590
591 r = dirty_map_init(cmd);
592 if (r)
593 goto out_with_pds;
594
595 if (bitmap_full(cmd->region_map, cmd->nr_regions))
596 cmd->hydration_done = true;
597
598 return cmd;
599
600out_with_pds:
601 __destroy_persistent_data_structures(cmd);
602
603out_with_region_map:
604 kvfree(cmd->region_map);
605
606out_with_md:
607 kfree(cmd);
608
609 return ERR_PTR(r);
610}
611
612void dm_clone_metadata_close(struct dm_clone_metadata *cmd)
613{
614 if (!cmd->fail_io)
615 __destroy_persistent_data_structures(cmd);
616
617 dirty_map_exit(cmd);
618 kvfree(cmd->region_map);
619 kfree(cmd);
620}
621
622bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd)
623{
624 return cmd->hydration_done;
625}
626
627bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr)
628{
629 return dm_clone_is_hydration_done(cmd) || test_bit(region_nr, cmd->region_map);
630}
631
632bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd,
633 unsigned long start, unsigned long nr_regions)
634{
635 unsigned long bit;
636
637 if (dm_clone_is_hydration_done(cmd))
638 return true;
639
640 bit = find_next_zero_bit(cmd->region_map, cmd->nr_regions, start);
641
642 return (bit >= (start + nr_regions));
643}
644
645unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd)
646{
647 return bitmap_weight(cmd->region_map, cmd->nr_regions);
648}
649
650unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd,
651 unsigned long start)
652{
653 return find_next_zero_bit(cmd->region_map, cmd->nr_regions, start);
654}
655
656static int __update_metadata_word(struct dm_clone_metadata *cmd,
657 unsigned long *dirty_regions,
658 unsigned long word)
659{
660 int r;
661 unsigned long index = word * BITS_PER_LONG;
662 unsigned long max_index = min(cmd->nr_regions, (word + 1) * BITS_PER_LONG);
663
664 while (index < max_index) {
665 if (test_bit(index, dirty_regions)) {
666 r = dm_bitset_set_bit(&cmd->bitset_info, cmd->bitset_root,
667 index, &cmd->bitset_root);
668 if (r) {
669 DMERR("dm_bitset_set_bit failed");
670 return r;
671 }
672 __clear_bit(index, dirty_regions);
673 }
674 index++;
675 }
676
677 return 0;
678}
679
680static int __metadata_commit(struct dm_clone_metadata *cmd)
681{
682 int r;
683 struct dm_block *sblock;
684 struct superblock_disk *sb;
685
686 /* Flush bitset cache */
687 r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root);
688 if (r) {
689 DMERR("dm_bitset_flush failed");
690 return r;
691 }
692
693 /* Flush to disk all blocks, except the superblock */
694 r = dm_tm_pre_commit(cmd->tm);
695 if (r) {
696 DMERR("dm_tm_pre_commit failed");
697 return r;
698 }
699
700 /* Save the space map root in cmd->metadata_space_map_root */
701 r = __copy_sm_root(cmd);
702 if (r) {
703 DMERR("__copy_sm_root failed");
704 return r;
705 }
706
707 /* Lock the superblock */
708 r = superblock_write_lock_zero(cmd, &sblock);
709 if (r) {
710 DMERR("Failed to write_lock superblock");
711 return r;
712 }
713
714 /* Save the metadata in superblock */
715 sb = dm_block_data(sblock);
716 __prepare_superblock(cmd, sb);
717
718 /* Unlock superblock and commit it to disk */
719 r = dm_tm_commit(cmd->tm, sblock);
720 if (r) {
721 DMERR("Failed to commit superblock");
722 return r;
723 }
724
725 /*
726 * FIXME: Find a more efficient way to check if the hydration is done.
727 */
728 if (bitmap_full(cmd->region_map, cmd->nr_regions))
729 cmd->hydration_done = true;
730
731 return 0;
732}
733
734static int __flush_dmap(struct dm_clone_metadata *cmd, struct dirty_map *dmap)
735{
736 int r;
737 unsigned long word;
738
739 word = 0;
740 do {
741 word = find_next_bit(dmap->dirty_words, cmd->nr_words, word);
742
743 if (word == cmd->nr_words)
744 break;
745
746 r = __update_metadata_word(cmd, dmap->dirty_regions, word);
747
748 if (r)
749 return r;
750
751 __clear_bit(word, dmap->dirty_words);
752 word++;
753 } while (word < cmd->nr_words);
754
755 r = __metadata_commit(cmd);
756
757 if (r)
758 return r;
759
760 /* Update the changed flag */
761 spin_lock_irq(&cmd->bitmap_lock);
762 dmap->changed = 0;
763 spin_unlock_irq(&cmd->bitmap_lock);
764
765 return 0;
766}
767
768int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd)
769{
770 int r = 0;
771 struct dirty_map *dmap, *next_dmap;
772
773 down_write(&cmd->lock);
774
775 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
776 r = -EPERM;
777 goto out;
778 }
779
780 /* Get current dirty bitmap */
781 dmap = cmd->current_dmap;
782
783 /* Get next dirty bitmap */
784 next_dmap = (dmap == &cmd->dmap[0]) ? &cmd->dmap[1] : &cmd->dmap[0];
785
786 /*
787 * The last commit failed, so we don't have a clean dirty-bitmap to
788 * use.
789 */
790 if (WARN_ON(next_dmap->changed || cmd->committing_dmap)) {
791 r = -EINVAL;
792 goto out;
793 }
794
795 /* Swap dirty bitmaps */
796 spin_lock_irq(&cmd->bitmap_lock);
797 cmd->current_dmap = next_dmap;
798 spin_unlock_irq(&cmd->bitmap_lock);
799
800 /* Set old dirty bitmap as currently committing */
801 cmd->committing_dmap = dmap;
802out:
803 up_write(&cmd->lock);
804
805 return r;
806}
807
808int dm_clone_metadata_commit(struct dm_clone_metadata *cmd)
809{
810 int r = -EPERM;
811
812 down_write(&cmd->lock);
813
814 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm))
815 goto out;
816
817 if (WARN_ON(!cmd->committing_dmap)) {
818 r = -EINVAL;
819 goto out;
820 }
821
822 r = __flush_dmap(cmd, cmd->committing_dmap);
823 if (!r) {
824 /* Clear committing dmap */
825 cmd->committing_dmap = NULL;
826 }
827out:
828 up_write(&cmd->lock);
829
830 return r;
831}
832
833int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr)
834{
835 int r = 0;
836 struct dirty_map *dmap;
837 unsigned long word, flags;
838
839 if (unlikely(region_nr >= cmd->nr_regions)) {
840 DMERR("Region %lu out of range (total number of regions %lu)",
841 region_nr, cmd->nr_regions);
842 return -ERANGE;
843 }
844
845 word = region_nr / BITS_PER_LONG;
846
847 spin_lock_irqsave(&cmd->bitmap_lock, flags);
848
849 if (cmd->read_only) {
850 r = -EPERM;
851 goto out;
852 }
853
854 dmap = cmd->current_dmap;
855
856 __set_bit(word, dmap->dirty_words);
857 __set_bit(region_nr, dmap->dirty_regions);
858 __set_bit(region_nr, cmd->region_map);
859 dmap->changed = 1;
860
861out:
862 spin_unlock_irqrestore(&cmd->bitmap_lock, flags);
863
864 return r;
865}
866
867int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start,
868 unsigned long nr_regions)
869{
870 int r = 0;
871 struct dirty_map *dmap;
872 unsigned long word, region_nr;
873
874 if (unlikely(start >= cmd->nr_regions || (start + nr_regions) < start ||
875 (start + nr_regions) > cmd->nr_regions)) {
876 DMERR("Invalid region range: start %lu, nr_regions %lu (total number of regions %lu)",
877 start, nr_regions, cmd->nr_regions);
878 return -ERANGE;
879 }
880
881 spin_lock_irq(&cmd->bitmap_lock);
882
883 if (cmd->read_only) {
884 r = -EPERM;
885 goto out;
886 }
887
888 dmap = cmd->current_dmap;
889 for (region_nr = start; region_nr < (start + nr_regions); region_nr++) {
890 if (!test_bit(region_nr, cmd->region_map)) {
891 word = region_nr / BITS_PER_LONG;
892 __set_bit(word, dmap->dirty_words);
893 __set_bit(region_nr, dmap->dirty_regions);
894 __set_bit(region_nr, cmd->region_map);
895 dmap->changed = 1;
896 }
897 }
898out:
899 spin_unlock_irq(&cmd->bitmap_lock);
900
901 return r;
902}
903
904/*
905 * WARNING: This must not be called concurrently with either
906 * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it changes
907 * cmd->region_map without taking the cmd->bitmap_lock spinlock. The only
908 * exception is after setting the metadata to read-only mode, using
909 * dm_clone_metadata_set_read_only().
910 *
911 * We don't take the spinlock because __load_bitset_in_core() does I/O, so it
912 * may block.
913 */
914int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd)
915{
916 int r = -EINVAL;
917
918 down_write(&cmd->lock);
919
920 if (cmd->fail_io)
921 goto out;
922
923 r = __load_bitset_in_core(cmd);
924out:
925 up_write(&cmd->lock);
926
927 return r;
928}
929
930bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd)
931{
932 bool r;
933 unsigned long flags;
934
935 spin_lock_irqsave(&cmd->bitmap_lock, flags);
936 r = cmd->dmap[0].changed || cmd->dmap[1].changed;
937 spin_unlock_irqrestore(&cmd->bitmap_lock, flags);
938
939 return r;
940}
941
942int dm_clone_metadata_abort(struct dm_clone_metadata *cmd)
943{
944 int r = -EPERM;
945
946 down_write(&cmd->lock);
947
948 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm))
949 goto out;
950
951 __destroy_persistent_data_structures(cmd);
952
953 r = __create_persistent_data_structures(cmd, false);
954 if (r) {
955 /* If something went wrong we can neither write nor read the metadata */
956 cmd->fail_io = true;
957 }
958out:
959 up_write(&cmd->lock);
960
961 return r;
962}
963
964void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd)
965{
966 down_write(&cmd->lock);
967
968 spin_lock_irq(&cmd->bitmap_lock);
969 cmd->read_only = 1;
970 spin_unlock_irq(&cmd->bitmap_lock);
971
972 if (!cmd->fail_io)
973 dm_bm_set_read_only(cmd->bm);
974
975 up_write(&cmd->lock);
976}
977
978void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd)
979{
980 down_write(&cmd->lock);
981
982 spin_lock_irq(&cmd->bitmap_lock);
983 cmd->read_only = 0;
984 spin_unlock_irq(&cmd->bitmap_lock);
985
986 if (!cmd->fail_io)
987 dm_bm_set_read_write(cmd->bm);
988
989 up_write(&cmd->lock);
990}
991
992int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd,
993 dm_block_t *result)
994{
995 int r = -EINVAL;
996
997 down_read(&cmd->lock);
998
999 if (!cmd->fail_io)
1000 r = dm_sm_get_nr_free(cmd->sm, result);
1001
1002 up_read(&cmd->lock);
1003
1004 return r;
1005}
1006
1007int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd,
1008 dm_block_t *result)
1009{
1010 int r = -EINVAL;
1011
1012 down_read(&cmd->lock);
1013
1014 if (!cmd->fail_io)
1015 r = dm_sm_get_nr_blocks(cmd->sm, result);
1016
1017 up_read(&cmd->lock);
1018
1019 return r;
1020}