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7431b783 NT |
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 | */ | |
38 | struct 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 | * | |
e6a505f3 NT |
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. | |
7431b783 NT |
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 | * | |
e6a505f3 NT |
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. | |
7431b783 | 92 | * |
e6a505f3 NT |
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. | |
7431b783 NT |
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 | * | |
e6a505f3 NT |
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. | |
7431b783 NT |
109 | */ |
110 | struct dirty_map { | |
111 | unsigned long *dirty_words; | |
e6a505f3 | 112 | unsigned long *dirty_regions; |
7431b783 NT |
113 | unsigned int changed; |
114 | }; | |
115 | ||
116 | struct 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 | ||
8fdbfe8d NT |
130 | /* Protected by lock */ |
131 | struct dirty_map *committing_dmap; | |
132 | ||
7431b783 NT |
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 | */ | |
166 | static void sb_prepare_for_write(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 | ||
180 | static int sb_check(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 | ||
223 | static 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 | */ | |
233 | static 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 | */ | |
273 | static 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 | ||
7431b783 NT |
279 | static 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 | ||
285 | static 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 */ | |
298 | static 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 | ||
318 | static 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 | ||
354 | out_with_lock: | |
355 | dm_bm_unlock(sblock); | |
356 | ||
357 | return r; | |
358 | } | |
359 | ||
360 | static 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 | ||
416 | err_with_tm: | |
417 | dm_sm_destroy(cmd->sm); | |
418 | dm_tm_destroy(cmd->tm); | |
419 | ||
420 | return r; | |
421 | } | |
422 | ||
423 | static 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 | ||
438 | static 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 | ||
459 | static 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 | ||
468 | static size_t bitmap_size(unsigned long nr_bits) | |
469 | { | |
470 | return BITS_TO_LONGS(nr_bits) * sizeof(long); | |
471 | } | |
472 | ||
e6a505f3 NT |
473 | static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words, |
474 | unsigned long nr_regions) | |
7431b783 | 475 | { |
e6a505f3 | 476 | dmap->changed = 0; |
7431b783 | 477 | |
e6a505f3 NT |
478 | dmap->dirty_words = kvzalloc(bitmap_size(nr_words), GFP_KERNEL); |
479 | if (!dmap->dirty_words) | |
480 | return -ENOMEM; | |
481 | ||
482 | dmap->dirty_regions = kvzalloc(bitmap_size(nr_regions), GFP_KERNEL); | |
483 | if (!dmap->dirty_regions) { | |
484 | kvfree(dmap->dirty_words); | |
7431b783 NT |
485 | return -ENOMEM; |
486 | } | |
487 | ||
e6a505f3 NT |
488 | return 0; |
489 | } | |
7431b783 | 490 | |
e6a505f3 NT |
491 | static void __dirty_map_exit(struct dirty_map *dmap) |
492 | { | |
493 | kvfree(dmap->dirty_words); | |
494 | kvfree(dmap->dirty_regions); | |
495 | } | |
496 | ||
497 | static int dirty_map_init(struct dm_clone_metadata *cmd) | |
498 | { | |
499 | if (__dirty_map_init(&cmd->dmap[0], cmd->nr_words, cmd->nr_regions)) { | |
7431b783 | 500 | DMERR("Failed to allocate dirty bitmap"); |
e6a505f3 NT |
501 | return -ENOMEM; |
502 | } | |
503 | ||
504 | if (__dirty_map_init(&cmd->dmap[1], cmd->nr_words, cmd->nr_regions)) { | |
505 | DMERR("Failed to allocate dirty bitmap"); | |
506 | __dirty_map_exit(&cmd->dmap[0]); | |
7431b783 NT |
507 | return -ENOMEM; |
508 | } | |
509 | ||
510 | cmd->current_dmap = &cmd->dmap[0]; | |
8fdbfe8d | 511 | cmd->committing_dmap = NULL; |
7431b783 NT |
512 | |
513 | return 0; | |
514 | } | |
515 | ||
516 | static void dirty_map_exit(struct dm_clone_metadata *cmd) | |
517 | { | |
e6a505f3 NT |
518 | __dirty_map_exit(&cmd->dmap[0]); |
519 | __dirty_map_exit(&cmd->dmap[1]); | |
7431b783 NT |
520 | } |
521 | ||
522 | static int __load_bitset_in_core(struct dm_clone_metadata *cmd) | |
523 | { | |
524 | int r; | |
525 | unsigned long i; | |
526 | struct dm_bitset_cursor c; | |
527 | ||
528 | /* Flush bitset cache */ | |
529 | r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root); | |
530 | if (r) | |
531 | return r; | |
532 | ||
533 | r = dm_bitset_cursor_begin(&cmd->bitset_info, cmd->bitset_root, cmd->nr_regions, &c); | |
534 | if (r) | |
535 | return r; | |
536 | ||
537 | for (i = 0; ; i++) { | |
538 | if (dm_bitset_cursor_get_value(&c)) | |
539 | __set_bit(i, cmd->region_map); | |
540 | else | |
541 | __clear_bit(i, cmd->region_map); | |
542 | ||
543 | if (i >= (cmd->nr_regions - 1)) | |
544 | break; | |
545 | ||
546 | r = dm_bitset_cursor_next(&c); | |
547 | ||
548 | if (r) | |
549 | break; | |
550 | } | |
551 | ||
552 | dm_bitset_cursor_end(&c); | |
553 | ||
554 | return r; | |
555 | } | |
556 | ||
557 | struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev, | |
558 | sector_t target_size, | |
559 | sector_t region_size) | |
560 | { | |
561 | int r; | |
562 | struct dm_clone_metadata *cmd; | |
563 | ||
564 | cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); | |
565 | if (!cmd) { | |
566 | DMERR("Failed to allocate memory for dm-clone metadata"); | |
567 | return ERR_PTR(-ENOMEM); | |
568 | } | |
569 | ||
570 | cmd->bdev = bdev; | |
571 | cmd->target_size = target_size; | |
572 | cmd->region_size = region_size; | |
573 | cmd->nr_regions = dm_sector_div_up(cmd->target_size, cmd->region_size); | |
574 | cmd->nr_words = BITS_TO_LONGS(cmd->nr_regions); | |
575 | ||
576 | init_rwsem(&cmd->lock); | |
577 | spin_lock_init(&cmd->bitmap_lock); | |
578 | cmd->read_only = 0; | |
579 | cmd->fail_io = false; | |
580 | cmd->hydration_done = false; | |
581 | ||
582 | cmd->region_map = kvmalloc(bitmap_size(cmd->nr_regions), GFP_KERNEL); | |
583 | if (!cmd->region_map) { | |
584 | DMERR("Failed to allocate memory for region bitmap"); | |
585 | r = -ENOMEM; | |
586 | goto out_with_md; | |
587 | } | |
588 | ||
589 | r = __create_persistent_data_structures(cmd, true); | |
590 | if (r) | |
591 | goto out_with_region_map; | |
592 | ||
593 | r = __load_bitset_in_core(cmd); | |
594 | if (r) { | |
595 | DMERR("Failed to load on-disk region map"); | |
596 | goto out_with_pds; | |
597 | } | |
598 | ||
599 | r = dirty_map_init(cmd); | |
600 | if (r) | |
601 | goto out_with_pds; | |
602 | ||
603 | if (bitmap_full(cmd->region_map, cmd->nr_regions)) | |
604 | cmd->hydration_done = true; | |
605 | ||
606 | return cmd; | |
607 | ||
608 | out_with_pds: | |
609 | __destroy_persistent_data_structures(cmd); | |
610 | ||
611 | out_with_region_map: | |
612 | kvfree(cmd->region_map); | |
613 | ||
614 | out_with_md: | |
615 | kfree(cmd); | |
616 | ||
617 | return ERR_PTR(r); | |
618 | } | |
619 | ||
620 | void dm_clone_metadata_close(struct dm_clone_metadata *cmd) | |
621 | { | |
622 | if (!cmd->fail_io) | |
623 | __destroy_persistent_data_structures(cmd); | |
624 | ||
625 | dirty_map_exit(cmd); | |
626 | kvfree(cmd->region_map); | |
627 | kfree(cmd); | |
628 | } | |
629 | ||
630 | bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd) | |
631 | { | |
632 | return cmd->hydration_done; | |
633 | } | |
634 | ||
635 | bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr) | |
636 | { | |
637 | return dm_clone_is_hydration_done(cmd) || test_bit(region_nr, cmd->region_map); | |
638 | } | |
639 | ||
640 | bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd, | |
641 | unsigned long start, unsigned long nr_regions) | |
642 | { | |
643 | unsigned long bit; | |
644 | ||
645 | if (dm_clone_is_hydration_done(cmd)) | |
646 | return true; | |
647 | ||
648 | bit = find_next_zero_bit(cmd->region_map, cmd->nr_regions, start); | |
649 | ||
650 | return (bit >= (start + nr_regions)); | |
651 | } | |
652 | ||
81d5553d | 653 | unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd) |
7431b783 NT |
654 | { |
655 | return bitmap_weight(cmd->region_map, cmd->nr_regions); | |
656 | } | |
657 | ||
658 | unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd, | |
659 | unsigned long start) | |
660 | { | |
661 | return find_next_zero_bit(cmd->region_map, cmd->nr_regions, start); | |
662 | } | |
663 | ||
e6a505f3 NT |
664 | static int __update_metadata_word(struct dm_clone_metadata *cmd, |
665 | unsigned long *dirty_regions, | |
666 | unsigned long word) | |
7431b783 NT |
667 | { |
668 | int r; | |
669 | unsigned long index = word * BITS_PER_LONG; | |
670 | unsigned long max_index = min(cmd->nr_regions, (word + 1) * BITS_PER_LONG); | |
671 | ||
672 | while (index < max_index) { | |
e6a505f3 | 673 | if (test_bit(index, dirty_regions)) { |
7431b783 NT |
674 | r = dm_bitset_set_bit(&cmd->bitset_info, cmd->bitset_root, |
675 | index, &cmd->bitset_root); | |
7431b783 NT |
676 | if (r) { |
677 | DMERR("dm_bitset_set_bit failed"); | |
678 | return r; | |
679 | } | |
e6a505f3 | 680 | __clear_bit(index, dirty_regions); |
7431b783 NT |
681 | } |
682 | index++; | |
683 | } | |
684 | ||
685 | return 0; | |
686 | } | |
687 | ||
688 | static int __metadata_commit(struct dm_clone_metadata *cmd) | |
689 | { | |
690 | int r; | |
691 | struct dm_block *sblock; | |
692 | struct superblock_disk *sb; | |
693 | ||
694 | /* Flush bitset cache */ | |
695 | r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root); | |
696 | if (r) { | |
697 | DMERR("dm_bitset_flush failed"); | |
698 | return r; | |
699 | } | |
700 | ||
701 | /* Flush to disk all blocks, except the superblock */ | |
702 | r = dm_tm_pre_commit(cmd->tm); | |
703 | if (r) { | |
704 | DMERR("dm_tm_pre_commit failed"); | |
705 | return r; | |
706 | } | |
707 | ||
708 | /* Save the space map root in cmd->metadata_space_map_root */ | |
709 | r = __copy_sm_root(cmd); | |
710 | if (r) { | |
711 | DMERR("__copy_sm_root failed"); | |
712 | return r; | |
713 | } | |
714 | ||
715 | /* Lock the superblock */ | |
716 | r = superblock_write_lock_zero(cmd, &sblock); | |
717 | if (r) { | |
718 | DMERR("Failed to write_lock superblock"); | |
719 | return r; | |
720 | } | |
721 | ||
722 | /* Save the metadata in superblock */ | |
723 | sb = dm_block_data(sblock); | |
724 | __prepare_superblock(cmd, sb); | |
725 | ||
726 | /* Unlock superblock and commit it to disk */ | |
727 | r = dm_tm_commit(cmd->tm, sblock); | |
728 | if (r) { | |
729 | DMERR("Failed to commit superblock"); | |
730 | return r; | |
731 | } | |
732 | ||
733 | /* | |
734 | * FIXME: Find a more efficient way to check if the hydration is done. | |
735 | */ | |
736 | if (bitmap_full(cmd->region_map, cmd->nr_regions)) | |
737 | cmd->hydration_done = true; | |
738 | ||
739 | return 0; | |
740 | } | |
741 | ||
742 | static int __flush_dmap(struct dm_clone_metadata *cmd, struct dirty_map *dmap) | |
743 | { | |
744 | int r; | |
6ca43ed8 | 745 | unsigned long word; |
7431b783 NT |
746 | |
747 | word = 0; | |
748 | do { | |
749 | word = find_next_bit(dmap->dirty_words, cmd->nr_words, word); | |
750 | ||
751 | if (word == cmd->nr_words) | |
752 | break; | |
753 | ||
e6a505f3 | 754 | r = __update_metadata_word(cmd, dmap->dirty_regions, word); |
7431b783 NT |
755 | |
756 | if (r) | |
757 | return r; | |
758 | ||
759 | __clear_bit(word, dmap->dirty_words); | |
760 | word++; | |
761 | } while (word < cmd->nr_words); | |
762 | ||
763 | r = __metadata_commit(cmd); | |
764 | ||
765 | if (r) | |
766 | return r; | |
767 | ||
768 | /* Update the changed flag */ | |
6ca43ed8 | 769 | spin_lock_irq(&cmd->bitmap_lock); |
7431b783 | 770 | dmap->changed = 0; |
6ca43ed8 | 771 | spin_unlock_irq(&cmd->bitmap_lock); |
7431b783 NT |
772 | |
773 | return 0; | |
774 | } | |
775 | ||
8fdbfe8d | 776 | int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd) |
7431b783 | 777 | { |
8fdbfe8d | 778 | int r = 0; |
7431b783 NT |
779 | struct dirty_map *dmap, *next_dmap; |
780 | ||
781 | down_write(&cmd->lock); | |
782 | ||
8fdbfe8d NT |
783 | if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { |
784 | r = -EPERM; | |
7431b783 | 785 | goto out; |
8fdbfe8d | 786 | } |
7431b783 NT |
787 | |
788 | /* Get current dirty bitmap */ | |
789 | dmap = cmd->current_dmap; | |
790 | ||
791 | /* Get next dirty bitmap */ | |
792 | next_dmap = (dmap == &cmd->dmap[0]) ? &cmd->dmap[1] : &cmd->dmap[0]; | |
793 | ||
794 | /* | |
795 | * The last commit failed, so we don't have a clean dirty-bitmap to | |
796 | * use. | |
797 | */ | |
8fdbfe8d | 798 | if (WARN_ON(next_dmap->changed || cmd->committing_dmap)) { |
7431b783 NT |
799 | r = -EINVAL; |
800 | goto out; | |
801 | } | |
802 | ||
803 | /* Swap dirty bitmaps */ | |
6ca43ed8 | 804 | spin_lock_irq(&cmd->bitmap_lock); |
7431b783 | 805 | cmd->current_dmap = next_dmap; |
6ca43ed8 | 806 | spin_unlock_irq(&cmd->bitmap_lock); |
7431b783 | 807 | |
8fdbfe8d NT |
808 | /* Set old dirty bitmap as currently committing */ |
809 | cmd->committing_dmap = dmap; | |
810 | out: | |
811 | up_write(&cmd->lock); | |
812 | ||
813 | return r; | |
814 | } | |
815 | ||
816 | int dm_clone_metadata_commit(struct dm_clone_metadata *cmd) | |
817 | { | |
818 | int r = -EPERM; | |
819 | ||
820 | down_write(&cmd->lock); | |
821 | ||
822 | if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) | |
823 | goto out; | |
824 | ||
825 | if (WARN_ON(!cmd->committing_dmap)) { | |
826 | r = -EINVAL; | |
827 | goto out; | |
828 | } | |
829 | ||
830 | r = __flush_dmap(cmd, cmd->committing_dmap); | |
831 | if (!r) { | |
832 | /* Clear committing dmap */ | |
833 | cmd->committing_dmap = NULL; | |
834 | } | |
7431b783 NT |
835 | out: |
836 | up_write(&cmd->lock); | |
837 | ||
838 | return r; | |
839 | } | |
840 | ||
841 | int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr) | |
842 | { | |
843 | int r = 0; | |
844 | struct dirty_map *dmap; | |
845 | unsigned long word, flags; | |
846 | ||
4b514290 NT |
847 | if (unlikely(region_nr >= cmd->nr_regions)) { |
848 | DMERR("Region %lu out of range (total number of regions %lu)", | |
849 | region_nr, cmd->nr_regions); | |
850 | return -ERANGE; | |
851 | } | |
852 | ||
7431b783 NT |
853 | word = region_nr / BITS_PER_LONG; |
854 | ||
855 | spin_lock_irqsave(&cmd->bitmap_lock, flags); | |
856 | ||
857 | if (cmd->read_only) { | |
858 | r = -EPERM; | |
859 | goto out; | |
860 | } | |
861 | ||
862 | dmap = cmd->current_dmap; | |
863 | ||
864 | __set_bit(word, dmap->dirty_words); | |
e6a505f3 | 865 | __set_bit(region_nr, dmap->dirty_regions); |
7431b783 NT |
866 | __set_bit(region_nr, cmd->region_map); |
867 | dmap->changed = 1; | |
868 | ||
869 | out: | |
870 | spin_unlock_irqrestore(&cmd->bitmap_lock, flags); | |
871 | ||
872 | return r; | |
873 | } | |
874 | ||
875 | int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start, | |
876 | unsigned long nr_regions) | |
877 | { | |
878 | int r = 0; | |
879 | struct dirty_map *dmap; | |
6ca43ed8 | 880 | unsigned long word, region_nr; |
7431b783 | 881 | |
4b514290 NT |
882 | if (unlikely(start >= cmd->nr_regions || (start + nr_regions) < start || |
883 | (start + nr_regions) > cmd->nr_regions)) { | |
884 | DMERR("Invalid region range: start %lu, nr_regions %lu (total number of regions %lu)", | |
885 | start, nr_regions, cmd->nr_regions); | |
886 | return -ERANGE; | |
887 | } | |
888 | ||
6ca43ed8 | 889 | spin_lock_irq(&cmd->bitmap_lock); |
7431b783 NT |
890 | |
891 | if (cmd->read_only) { | |
892 | r = -EPERM; | |
893 | goto out; | |
894 | } | |
895 | ||
896 | dmap = cmd->current_dmap; | |
897 | for (region_nr = start; region_nr < (start + nr_regions); region_nr++) { | |
898 | if (!test_bit(region_nr, cmd->region_map)) { | |
899 | word = region_nr / BITS_PER_LONG; | |
900 | __set_bit(word, dmap->dirty_words); | |
e6a505f3 | 901 | __set_bit(region_nr, dmap->dirty_regions); |
7431b783 NT |
902 | __set_bit(region_nr, cmd->region_map); |
903 | dmap->changed = 1; | |
904 | } | |
905 | } | |
906 | out: | |
6ca43ed8 | 907 | spin_unlock_irq(&cmd->bitmap_lock); |
7431b783 NT |
908 | |
909 | return r; | |
910 | } | |
911 | ||
912 | /* | |
913 | * WARNING: This must not be called concurrently with either | |
914 | * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it changes | |
915 | * cmd->region_map without taking the cmd->bitmap_lock spinlock. The only | |
916 | * exception is after setting the metadata to read-only mode, using | |
917 | * dm_clone_metadata_set_read_only(). | |
918 | * | |
919 | * We don't take the spinlock because __load_bitset_in_core() does I/O, so it | |
920 | * may block. | |
921 | */ | |
922 | int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd) | |
923 | { | |
924 | int r = -EINVAL; | |
925 | ||
926 | down_write(&cmd->lock); | |
927 | ||
928 | if (cmd->fail_io) | |
929 | goto out; | |
930 | ||
931 | r = __load_bitset_in_core(cmd); | |
932 | out: | |
933 | up_write(&cmd->lock); | |
934 | ||
935 | return r; | |
936 | } | |
937 | ||
938 | bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd) | |
939 | { | |
940 | bool r; | |
941 | unsigned long flags; | |
942 | ||
943 | spin_lock_irqsave(&cmd->bitmap_lock, flags); | |
944 | r = cmd->dmap[0].changed || cmd->dmap[1].changed; | |
945 | spin_unlock_irqrestore(&cmd->bitmap_lock, flags); | |
946 | ||
947 | return r; | |
948 | } | |
949 | ||
950 | int dm_clone_metadata_abort(struct dm_clone_metadata *cmd) | |
951 | { | |
952 | int r = -EPERM; | |
953 | ||
954 | down_write(&cmd->lock); | |
955 | ||
956 | if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) | |
957 | goto out; | |
958 | ||
959 | __destroy_persistent_data_structures(cmd); | |
960 | ||
961 | r = __create_persistent_data_structures(cmd, false); | |
962 | if (r) { | |
963 | /* If something went wrong we can neither write nor read the metadata */ | |
964 | cmd->fail_io = true; | |
965 | } | |
966 | out: | |
967 | up_write(&cmd->lock); | |
968 | ||
969 | return r; | |
970 | } | |
971 | ||
972 | void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd) | |
973 | { | |
7431b783 NT |
974 | down_write(&cmd->lock); |
975 | ||
6ca43ed8 | 976 | spin_lock_irq(&cmd->bitmap_lock); |
7431b783 | 977 | cmd->read_only = 1; |
6ca43ed8 | 978 | spin_unlock_irq(&cmd->bitmap_lock); |
7431b783 NT |
979 | |
980 | if (!cmd->fail_io) | |
981 | dm_bm_set_read_only(cmd->bm); | |
982 | ||
983 | up_write(&cmd->lock); | |
984 | } | |
985 | ||
986 | void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd) | |
987 | { | |
7431b783 NT |
988 | down_write(&cmd->lock); |
989 | ||
6ca43ed8 | 990 | spin_lock_irq(&cmd->bitmap_lock); |
7431b783 | 991 | cmd->read_only = 0; |
6ca43ed8 | 992 | spin_unlock_irq(&cmd->bitmap_lock); |
7431b783 NT |
993 | |
994 | if (!cmd->fail_io) | |
995 | dm_bm_set_read_write(cmd->bm); | |
996 | ||
997 | up_write(&cmd->lock); | |
998 | } | |
999 | ||
1000 | int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd, | |
1001 | dm_block_t *result) | |
1002 | { | |
1003 | int r = -EINVAL; | |
1004 | ||
1005 | down_read(&cmd->lock); | |
1006 | ||
1007 | if (!cmd->fail_io) | |
1008 | r = dm_sm_get_nr_free(cmd->sm, result); | |
1009 | ||
1010 | up_read(&cmd->lock); | |
1011 | ||
1012 | return r; | |
1013 | } | |
1014 | ||
1015 | int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd, | |
1016 | dm_block_t *result) | |
1017 | { | |
1018 | int r = -EINVAL; | |
1019 | ||
1020 | down_read(&cmd->lock); | |
1021 | ||
1022 | if (!cmd->fail_io) | |
1023 | r = dm_sm_get_nr_blocks(cmd->sm, result); | |
1024 | ||
1025 | up_read(&cmd->lock); | |
1026 | ||
1027 | return r; | |
1028 | } |