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 | * |
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 | */ |
110 | struct dirty_map { |
111 | unsigned long *dirty_words; |
112 | unsigned long *dirty_regions; |
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 | |
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 | */ |
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(data: &sb->flags, len: 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(data: &sb->flags, len: 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, result: &sblock); |
245 | if (r) { |
246 | DMERR("Failed to read_lock superblock" ); |
247 | return r; |
248 | } |
249 | |
250 | data_le = dm_block_data(b: 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(b: 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(bm: cmd->bm, SUPERBLOCK_LOCATION, v: &sb_validator, result: sblock); |
277 | } |
278 | |
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(bm: cmd->bm, SUPERBLOCK_LOCATION, v: &sb_validator, result: 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(sm: cmd->sm, result: &root_size); |
291 | if (r) |
292 | return r; |
293 | |
294 | return dm_sm_copy_root(sm: cmd->sm, copy_to_here_le: &cmd->metadata_space_map_root, len: 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: &sblock); |
325 | |
326 | if (r) { |
327 | DMERR("Failed to read_lock superblock" ); |
328 | return r; |
329 | } |
330 | |
331 | sb = dm_block_data(b: 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(bm: cmd->bm, SUPERBLOCK_LOCATION, |
342 | sm_root: sb->metadata_space_map_root, |
343 | root_len: sizeof(sb->metadata_space_map_root), |
344 | tm: &cmd->tm, sm: &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(tm: cmd->tm, info: &cmd->bitset_info); |
352 | cmd->bitset_root = le64_to_cpu(sb->bitset_root); |
353 | |
354 | out_with_lock: |
355 | dm_bm_unlock(b: 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(bm: cmd->bm, SUPERBLOCK_LOCATION, tm: &cmd->tm, sm: &cmd->sm); |
367 | if (r) { |
368 | DMERR("Failed to create transaction manager" ); |
369 | return r; |
370 | } |
371 | |
372 | dm_disk_bitset_init(tm: cmd->tm, info: &cmd->bitset_info); |
373 | |
374 | r = dm_bitset_empty(info: &cmd->bitset_info, new_root: &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(info: &cmd->bitset_info, old_root: cmd->bitset_root, old_nr_entries: 0, |
381 | new_nr_entries: cmd->nr_regions, default_value: false, new_root: &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(tm: 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: &sblock); |
401 | if (r) { |
402 | DMERR("Failed to write_lock superblock" ); |
403 | goto err_with_tm; |
404 | } |
405 | |
406 | sb = dm_block_data(b: sblock); |
407 | __prepare_superblock(cmd, sb); |
408 | r = dm_tm_commit(tm: cmd->tm, superblock: 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(sm: cmd->sm); |
418 | dm_tm_destroy(tm: 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(bm: cmd->bm, formatted: &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(bdev: cmd->bdev, |
445 | DM_CLONE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, |
446 | DM_CLONE_MAX_CONCURRENT_LOCKS); |
447 | if (IS_ERR(ptr: cmd->bm)) { |
448 | DMERR("Failed to create block manager" ); |
449 | return PTR_ERR(ptr: cmd->bm); |
450 | } |
451 | |
452 | r = __open_or_format_metadata(cmd, may_format_device); |
453 | if (r) |
454 | dm_block_manager_destroy(bm: 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(sm: cmd->sm); |
462 | dm_tm_destroy(tm: cmd->tm); |
463 | dm_block_manager_destroy(bm: 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 | |
473 | static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words, |
474 | unsigned long nr_regions) |
475 | { |
476 | dmap->changed = 0; |
477 | |
478 | dmap->dirty_words = kvzalloc(size: bitmap_size(nr_bits: nr_words), GFP_KERNEL); |
479 | if (!dmap->dirty_words) |
480 | return -ENOMEM; |
481 | |
482 | dmap->dirty_regions = kvzalloc(size: bitmap_size(nr_bits: nr_regions), GFP_KERNEL); |
483 | if (!dmap->dirty_regions) { |
484 | kvfree(addr: dmap->dirty_words); |
485 | return -ENOMEM; |
486 | } |
487 | |
488 | return 0; |
489 | } |
490 | |
491 | static void __dirty_map_exit(struct dirty_map *dmap) |
492 | { |
493 | kvfree(addr: dmap->dirty_words); |
494 | kvfree(addr: dmap->dirty_regions); |
495 | } |
496 | |
497 | static int dirty_map_init(struct dm_clone_metadata *cmd) |
498 | { |
499 | if (__dirty_map_init(dmap: &cmd->dmap[0], nr_words: cmd->nr_words, nr_regions: cmd->nr_regions)) { |
500 | DMERR("Failed to allocate dirty bitmap" ); |
501 | return -ENOMEM; |
502 | } |
503 | |
504 | if (__dirty_map_init(dmap: &cmd->dmap[1], nr_words: cmd->nr_words, nr_regions: cmd->nr_regions)) { |
505 | DMERR("Failed to allocate dirty bitmap" ); |
506 | __dirty_map_exit(dmap: &cmd->dmap[0]); |
507 | return -ENOMEM; |
508 | } |
509 | |
510 | cmd->current_dmap = &cmd->dmap[0]; |
511 | cmd->committing_dmap = NULL; |
512 | |
513 | return 0; |
514 | } |
515 | |
516 | static void dirty_map_exit(struct dm_clone_metadata *cmd) |
517 | { |
518 | __dirty_map_exit(dmap: &cmd->dmap[0]); |
519 | __dirty_map_exit(dmap: &cmd->dmap[1]); |
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(info: &cmd->bitset_info, root: cmd->bitset_root, new_root: &cmd->bitset_root); |
530 | if (r) |
531 | return r; |
532 | |
533 | r = dm_bitset_cursor_begin(info: &cmd->bitset_info, root: cmd->bitset_root, nr_entries: cmd->nr_regions, c: &c); |
534 | if (r) |
535 | return r; |
536 | |
537 | for (i = 0; ; i++) { |
538 | if (dm_bitset_cursor_get_value(c: &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: &c); |
547 | |
548 | if (r) |
549 | break; |
550 | } |
551 | |
552 | dm_bitset_cursor_end(c: &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(size: sizeof(*cmd), GFP_KERNEL); |
565 | if (!cmd) { |
566 | DMERR("Failed to allocate memory for dm-clone metadata" ); |
567 | return ERR_PTR(error: -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(size: bitmap_size(nr_bits: 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, may_format_device: 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(src: cmd->region_map, nbits: 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(addr: cmd->region_map); |
613 | |
614 | out_with_md: |
615 | kfree(objp: cmd); |
616 | |
617 | return ERR_PTR(error: 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(addr: cmd->region_map); |
627 | kfree(objp: 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(addr: cmd->region_map, size: cmd->nr_regions, offset: start); |
649 | |
650 | return (bit >= (start + nr_regions)); |
651 | } |
652 | |
653 | unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd) |
654 | { |
655 | return bitmap_weight(src: cmd->region_map, nbits: 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(addr: cmd->region_map, size: cmd->nr_regions, offset: start); |
662 | } |
663 | |
664 | static int __update_metadata_word(struct dm_clone_metadata *cmd, |
665 | unsigned long *dirty_regions, |
666 | unsigned long word) |
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) { |
673 | if (test_bit(index, dirty_regions)) { |
674 | r = dm_bitset_set_bit(info: &cmd->bitset_info, root: cmd->bitset_root, |
675 | index, new_root: &cmd->bitset_root); |
676 | if (r) { |
677 | DMERR("dm_bitset_set_bit failed" ); |
678 | return r; |
679 | } |
680 | __clear_bit(index, dirty_regions); |
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(info: &cmd->bitset_info, root: cmd->bitset_root, new_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(tm: 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: &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(b: sblock); |
724 | __prepare_superblock(cmd, sb); |
725 | |
726 | /* Unlock superblock and commit it to disk */ |
727 | r = dm_tm_commit(tm: cmd->tm, superblock: 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(src: cmd->region_map, nbits: 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; |
745 | unsigned long word; |
746 | |
747 | word = 0; |
748 | do { |
749 | word = find_next_bit(addr: dmap->dirty_words, size: cmd->nr_words, offset: word); |
750 | |
751 | if (word == cmd->nr_words) |
752 | break; |
753 | |
754 | r = __update_metadata_word(cmd, dirty_regions: dmap->dirty_regions, word); |
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 */ |
769 | spin_lock_irq(lock: &cmd->bitmap_lock); |
770 | dmap->changed = 0; |
771 | spin_unlock_irq(lock: &cmd->bitmap_lock); |
772 | |
773 | return 0; |
774 | } |
775 | |
776 | int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd) |
777 | { |
778 | int r = 0; |
779 | struct dirty_map *dmap, *next_dmap; |
780 | |
781 | down_write(sem: &cmd->lock); |
782 | |
783 | if (cmd->fail_io || dm_bm_is_read_only(bm: cmd->bm)) { |
784 | r = -EPERM; |
785 | goto out; |
786 | } |
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 | */ |
798 | if (WARN_ON(next_dmap->changed || cmd->committing_dmap)) { |
799 | r = -EINVAL; |
800 | goto out; |
801 | } |
802 | |
803 | /* Swap dirty bitmaps */ |
804 | spin_lock_irq(lock: &cmd->bitmap_lock); |
805 | cmd->current_dmap = next_dmap; |
806 | spin_unlock_irq(lock: &cmd->bitmap_lock); |
807 | |
808 | /* Set old dirty bitmap as currently committing */ |
809 | cmd->committing_dmap = dmap; |
810 | out: |
811 | up_write(sem: &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(sem: &cmd->lock); |
821 | |
822 | if (cmd->fail_io || dm_bm_is_read_only(bm: 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, dmap: cmd->committing_dmap); |
831 | if (!r) { |
832 | /* Clear committing dmap */ |
833 | cmd->committing_dmap = NULL; |
834 | } |
835 | out: |
836 | up_write(sem: &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 | |
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 | |
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); |
865 | __set_bit(region_nr, dmap->dirty_regions); |
866 | __set_bit(region_nr, cmd->region_map); |
867 | dmap->changed = 1; |
868 | |
869 | out: |
870 | spin_unlock_irqrestore(lock: &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; |
880 | unsigned long word, region_nr; |
881 | |
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 | |
889 | spin_lock_irq(lock: &cmd->bitmap_lock); |
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); |
901 | __set_bit(region_nr, dmap->dirty_regions); |
902 | __set_bit(region_nr, cmd->region_map); |
903 | dmap->changed = 1; |
904 | } |
905 | } |
906 | out: |
907 | spin_unlock_irq(lock: &cmd->bitmap_lock); |
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(sem: &cmd->lock); |
927 | |
928 | if (cmd->fail_io) |
929 | goto out; |
930 | |
931 | r = __load_bitset_in_core(cmd); |
932 | out: |
933 | up_write(sem: &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(lock: &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(sem: &cmd->lock); |
955 | |
956 | if (cmd->fail_io || dm_bm_is_read_only(bm: cmd->bm)) |
957 | goto out; |
958 | |
959 | __destroy_persistent_data_structures(cmd); |
960 | |
961 | r = __create_persistent_data_structures(cmd, may_format_device: 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(sem: &cmd->lock); |
968 | |
969 | return r; |
970 | } |
971 | |
972 | void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd) |
973 | { |
974 | down_write(sem: &cmd->lock); |
975 | |
976 | spin_lock_irq(lock: &cmd->bitmap_lock); |
977 | cmd->read_only = 1; |
978 | spin_unlock_irq(lock: &cmd->bitmap_lock); |
979 | |
980 | if (!cmd->fail_io) |
981 | dm_bm_set_read_only(bm: cmd->bm); |
982 | |
983 | up_write(sem: &cmd->lock); |
984 | } |
985 | |
986 | void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd) |
987 | { |
988 | down_write(sem: &cmd->lock); |
989 | |
990 | spin_lock_irq(lock: &cmd->bitmap_lock); |
991 | cmd->read_only = 0; |
992 | spin_unlock_irq(lock: &cmd->bitmap_lock); |
993 | |
994 | if (!cmd->fail_io) |
995 | dm_bm_set_read_write(bm: cmd->bm); |
996 | |
997 | up_write(sem: &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(sem: &cmd->lock); |
1006 | |
1007 | if (!cmd->fail_io) |
1008 | r = dm_sm_get_nr_free(sm: cmd->sm, count: result); |
1009 | |
1010 | up_read(sem: &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(sem: &cmd->lock); |
1021 | |
1022 | if (!cmd->fail_io) |
1023 | r = dm_sm_get_nr_blocks(sm: cmd->sm, count: result); |
1024 | |
1025 | up_read(sem: &cmd->lock); |
1026 | |
1027 | return r; |
1028 | } |
1029 | |