1 // SPDX-License-Identifier: GPL-2.0-only
3 #include "persistent-data/dm-transaction-manager.h"
4 #include "persistent-data/dm-bitset.h"
5 #include "persistent-data/dm-space-map.h"
7 #include <linux/dm-io.h>
8 #include <linux/dm-kcopyd.h>
9 #include <linux/init.h>
10 #include <linux/mempool.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/vmalloc.h>
15 #define DM_MSG_PREFIX "era"
17 #define SUPERBLOCK_LOCATION 0
18 #define SUPERBLOCK_MAGIC 2126579579
19 #define SUPERBLOCK_CSUM_XOR 146538381
20 #define MIN_ERA_VERSION 1
21 #define MAX_ERA_VERSION 1
22 #define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION
23 #define MIN_BLOCK_SIZE 8
25 /*----------------------------------------------------------------
27 *--------------------------------------------------------------*/
28 struct writeset_metadata {
34 struct writeset_metadata md;
37 * An in core copy of the bits to save constantly doing look ups on
44 * This does not free off the on disk bitset as this will normally be done
45 * after digesting into the era array.
47 static void writeset_free(struct writeset *ws)
52 static int setup_on_disk_bitset(struct dm_disk_bitset *info,
53 unsigned nr_bits, dm_block_t *root)
57 r = dm_bitset_empty(info, root);
61 return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
64 static size_t bitset_size(unsigned nr_bits)
66 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
70 * Allocates memory for the in core bitset.
72 static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
74 ws->bits = vzalloc(bitset_size(nr_blocks));
76 DMERR("%s: couldn't allocate in memory bitset", __func__);
84 * Wipes the in-core bitset, and creates a new on disk bitset.
86 static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws,
91 memset(ws->bits, 0, bitset_size(nr_blocks));
93 ws->md.nr_bits = nr_blocks;
94 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
96 DMERR("%s: setup_on_disk_bitset failed", __func__);
103 static bool writeset_marked(struct writeset *ws, dm_block_t block)
105 return test_bit(block, ws->bits);
108 static int writeset_marked_on_disk(struct dm_disk_bitset *info,
109 struct writeset_metadata *m, dm_block_t block,
112 dm_block_t old = m->root;
115 * The bitset was flushed when it was archived, so we know there'll
116 * be no change to the root.
118 int r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
120 DMERR("%s: dm_bitset_test_bit failed", __func__);
124 BUG_ON(m->root != old);
130 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
132 static int writeset_test_and_set(struct dm_disk_bitset *info,
133 struct writeset *ws, uint32_t block)
137 if (!test_and_set_bit(block, ws->bits)) {
138 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
140 /* FIXME: fail mode */
150 /*----------------------------------------------------------------
151 * On disk metadata layout
152 *--------------------------------------------------------------*/
153 #define SPACE_MAP_ROOT_SIZE 128
156 struct writeset_disk {
161 struct superblock_disk {
170 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
172 __le32 data_block_size;
173 __le32 metadata_block_size;
177 struct writeset_disk current_writeset;
180 * Only these two fields are valid within the metadata snapshot.
182 __le64 writeset_tree_root;
183 __le64 era_array_root;
185 __le64 metadata_snap;
188 /*----------------------------------------------------------------
189 * Superblock validation
190 *--------------------------------------------------------------*/
191 static void sb_prepare_for_write(struct dm_block_validator *v,
193 size_t sb_block_size)
195 struct superblock_disk *disk = dm_block_data(b);
197 disk->blocknr = cpu_to_le64(dm_block_location(b));
198 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
199 sb_block_size - sizeof(__le32),
200 SUPERBLOCK_CSUM_XOR));
203 static int check_metadata_version(struct superblock_disk *disk)
205 uint32_t metadata_version = le32_to_cpu(disk->version);
206 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
207 DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
208 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
215 static int sb_check(struct dm_block_validator *v,
217 size_t sb_block_size)
219 struct superblock_disk *disk = dm_block_data(b);
222 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
223 DMERR("sb_check failed: blocknr %llu: wanted %llu",
224 le64_to_cpu(disk->blocknr),
225 (unsigned long long)dm_block_location(b));
229 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
230 DMERR("sb_check failed: magic %llu: wanted %llu",
231 le64_to_cpu(disk->magic),
232 (unsigned long long) SUPERBLOCK_MAGIC);
236 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
237 sb_block_size - sizeof(__le32),
238 SUPERBLOCK_CSUM_XOR));
239 if (csum_le != disk->csum) {
240 DMERR("sb_check failed: csum %u: wanted %u",
241 le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
245 return check_metadata_version(disk);
248 static struct dm_block_validator sb_validator = {
249 .name = "superblock",
250 .prepare_for_write = sb_prepare_for_write,
254 /*----------------------------------------------------------------
255 * Low level metadata handling
256 *--------------------------------------------------------------*/
257 #define DM_ERA_METADATA_BLOCK_SIZE 4096
258 #define ERA_MAX_CONCURRENT_LOCKS 5
260 struct era_metadata {
261 struct block_device *bdev;
262 struct dm_block_manager *bm;
263 struct dm_space_map *sm;
264 struct dm_transaction_manager *tm;
266 dm_block_t block_size;
269 uint32_t current_era;
272 * We preallocate 2 writesets. When an era rolls over we
273 * switch between them. This means the allocation is done at
274 * preresume time, rather than on the io path.
276 struct writeset writesets[2];
277 struct writeset *current_writeset;
279 dm_block_t writeset_tree_root;
280 dm_block_t era_array_root;
282 struct dm_disk_bitset bitset_info;
283 struct dm_btree_info writeset_tree_info;
284 struct dm_array_info era_array_info;
286 dm_block_t metadata_snap;
289 * A flag that is set whenever a writeset has been archived.
291 bool archived_writesets;
294 * Reading the space map root can fail, so we read it into this
295 * buffer before the superblock is locked and updated.
297 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
300 static int superblock_read_lock(struct era_metadata *md,
301 struct dm_block **sblock)
303 return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
304 &sb_validator, sblock);
307 static int superblock_lock_zero(struct era_metadata *md,
308 struct dm_block **sblock)
310 return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
311 &sb_validator, sblock);
314 static int superblock_lock(struct era_metadata *md,
315 struct dm_block **sblock)
317 return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
318 &sb_validator, sblock);
321 /* FIXME: duplication with cache and thin */
322 static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
327 __le64 *data_le, zero = cpu_to_le64(0);
328 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
331 * We can't use a validator here - it may be all zeroes.
333 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
337 data_le = dm_block_data(b);
339 for (i = 0; i < sb_block_size; i++) {
340 if (data_le[i] != zero) {
351 /*----------------------------------------------------------------*/
353 static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
355 disk->nr_bits = cpu_to_le32(core->nr_bits);
356 disk->root = cpu_to_le64(core->root);
359 static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
361 core->nr_bits = le32_to_cpu(disk->nr_bits);
362 core->root = le64_to_cpu(disk->root);
365 static void ws_inc(void *context, const void *value)
367 struct era_metadata *md = context;
368 struct writeset_disk ws_d;
371 memcpy(&ws_d, value, sizeof(ws_d));
372 b = le64_to_cpu(ws_d.root);
374 dm_tm_inc(md->tm, b);
377 static void ws_dec(void *context, const void *value)
379 struct era_metadata *md = context;
380 struct writeset_disk ws_d;
383 memcpy(&ws_d, value, sizeof(ws_d));
384 b = le64_to_cpu(ws_d.root);
386 dm_bitset_del(&md->bitset_info, b);
389 static int ws_eq(void *context, const void *value1, const void *value2)
391 return !memcmp(value1, value2, sizeof(struct writeset_metadata));
394 /*----------------------------------------------------------------*/
396 static void setup_writeset_tree_info(struct era_metadata *md)
398 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
399 md->writeset_tree_info.tm = md->tm;
400 md->writeset_tree_info.levels = 1;
402 vt->size = sizeof(struct writeset_disk);
408 static void setup_era_array_info(struct era_metadata *md)
411 struct dm_btree_value_type vt;
413 vt.size = sizeof(__le32);
418 dm_array_info_init(&md->era_array_info, md->tm, &vt);
421 static void setup_infos(struct era_metadata *md)
423 dm_disk_bitset_init(md->tm, &md->bitset_info);
424 setup_writeset_tree_info(md);
425 setup_era_array_info(md);
428 /*----------------------------------------------------------------*/
430 static int create_fresh_metadata(struct era_metadata *md)
434 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
437 DMERR("dm_tm_create_with_sm failed");
443 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
445 DMERR("couldn't create new writeset tree");
449 r = dm_array_empty(&md->era_array_info, &md->era_array_root);
451 DMERR("couldn't create era array");
458 dm_sm_destroy(md->sm);
459 dm_tm_destroy(md->tm);
464 static int save_sm_root(struct era_metadata *md)
469 r = dm_sm_root_size(md->sm, &metadata_len);
473 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
477 static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
479 memcpy(&disk->metadata_space_map_root,
480 &md->metadata_space_map_root,
481 sizeof(md->metadata_space_map_root));
485 * Writes a superblock, including the static fields that don't get updated
486 * with every commit (possible optimisation here). 'md' should be fully
487 * constructed when this is called.
489 static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
491 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
492 disk->flags = cpu_to_le32(0ul);
494 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
495 memset(disk->uuid, 0, sizeof(disk->uuid));
496 disk->version = cpu_to_le32(MAX_ERA_VERSION);
498 copy_sm_root(md, disk);
500 disk->data_block_size = cpu_to_le32(md->block_size);
501 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
502 disk->nr_blocks = cpu_to_le32(md->nr_blocks);
503 disk->current_era = cpu_to_le32(md->current_era);
505 ws_pack(&md->current_writeset->md, &disk->current_writeset);
506 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
507 disk->era_array_root = cpu_to_le64(md->era_array_root);
508 disk->metadata_snap = cpu_to_le64(md->metadata_snap);
511 static int write_superblock(struct era_metadata *md)
514 struct dm_block *sblock;
515 struct superblock_disk *disk;
517 r = save_sm_root(md);
519 DMERR("%s: save_sm_root failed", __func__);
523 r = superblock_lock_zero(md, &sblock);
527 disk = dm_block_data(sblock);
528 prepare_superblock(md, disk);
530 return dm_tm_commit(md->tm, sblock);
534 * Assumes block_size and the infos are set.
536 static int format_metadata(struct era_metadata *md)
540 r = create_fresh_metadata(md);
544 r = write_superblock(md);
546 dm_sm_destroy(md->sm);
547 dm_tm_destroy(md->tm);
554 static int open_metadata(struct era_metadata *md)
557 struct dm_block *sblock;
558 struct superblock_disk *disk;
560 r = superblock_read_lock(md, &sblock);
562 DMERR("couldn't read_lock superblock");
566 disk = dm_block_data(sblock);
567 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
568 disk->metadata_space_map_root,
569 sizeof(disk->metadata_space_map_root),
572 DMERR("dm_tm_open_with_sm failed");
578 md->block_size = le32_to_cpu(disk->data_block_size);
579 md->nr_blocks = le32_to_cpu(disk->nr_blocks);
580 md->current_era = le32_to_cpu(disk->current_era);
582 ws_unpack(&disk->current_writeset, &md->current_writeset->md);
583 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
584 md->era_array_root = le64_to_cpu(disk->era_array_root);
585 md->metadata_snap = le64_to_cpu(disk->metadata_snap);
586 md->archived_writesets = true;
588 dm_bm_unlock(sblock);
593 dm_bm_unlock(sblock);
597 static int open_or_format_metadata(struct era_metadata *md,
601 bool unformatted = false;
603 r = superblock_all_zeroes(md->bm, &unformatted);
608 return may_format ? format_metadata(md) : -EPERM;
610 return open_metadata(md);
613 static int create_persistent_data_objects(struct era_metadata *md,
618 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
619 ERA_MAX_CONCURRENT_LOCKS);
620 if (IS_ERR(md->bm)) {
621 DMERR("could not create block manager");
622 return PTR_ERR(md->bm);
625 r = open_or_format_metadata(md, may_format);
627 dm_block_manager_destroy(md->bm);
632 static void destroy_persistent_data_objects(struct era_metadata *md)
634 dm_sm_destroy(md->sm);
635 dm_tm_destroy(md->tm);
636 dm_block_manager_destroy(md->bm);
640 * This waits until all era_map threads have picked up the new filter.
642 static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
644 rcu_assign_pointer(md->current_writeset, new_writeset);
648 /*----------------------------------------------------------------
649 * Writesets get 'digested' into the main era array.
651 * We're using a coroutine here so the worker thread can do the digestion,
652 * thus avoiding synchronisation of the metadata. Digesting a whole
653 * writeset in one go would cause too much latency.
654 *--------------------------------------------------------------*/
657 unsigned nr_bits, current_bit;
658 struct writeset_metadata writeset;
660 struct dm_disk_bitset info;
662 int (*step)(struct era_metadata *, struct digest *);
665 static int metadata_digest_lookup_writeset(struct era_metadata *md,
668 static int metadata_digest_remove_writeset(struct era_metadata *md,
672 uint64_t key = d->era;
674 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
675 &key, &md->writeset_tree_root);
677 DMERR("%s: dm_btree_remove failed", __func__);
681 d->step = metadata_digest_lookup_writeset;
685 #define INSERTS_PER_STEP 100
687 static int metadata_digest_transcribe_writeset(struct era_metadata *md,
692 unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
694 for (b = d->current_bit; b < e; b++) {
695 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
697 DMERR("%s: writeset_marked_on_disk failed", __func__);
704 __dm_bless_for_disk(&d->value);
705 r = dm_array_set_value(&md->era_array_info, md->era_array_root,
706 b, &d->value, &md->era_array_root);
708 DMERR("%s: dm_array_set_value failed", __func__);
714 d->step = metadata_digest_remove_writeset;
721 static int metadata_digest_lookup_writeset(struct era_metadata *md,
726 struct writeset_disk disk;
728 r = dm_btree_find_lowest_key(&md->writeset_tree_info,
729 md->writeset_tree_root, &key);
735 r = dm_btree_lookup(&md->writeset_tree_info,
736 md->writeset_tree_root, &key, &disk);
743 DMERR("%s: dm_btree_lookup failed", __func__);
747 ws_unpack(&disk, &d->writeset);
748 d->value = cpu_to_le32(key);
750 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
752 d->step = metadata_digest_transcribe_writeset;
757 static int metadata_digest_start(struct era_metadata *md, struct digest *d)
762 memset(d, 0, sizeof(*d));
765 * We initialise another bitset info to avoid any caching side
766 * effects with the previous one.
768 dm_disk_bitset_init(md->tm, &d->info);
769 d->step = metadata_digest_lookup_writeset;
774 /*----------------------------------------------------------------
775 * High level metadata interface. Target methods should use these, and not
776 * the lower level ones.
777 *--------------------------------------------------------------*/
778 static struct era_metadata *metadata_open(struct block_device *bdev,
783 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
789 md->block_size = block_size;
791 md->writesets[0].md.root = INVALID_WRITESET_ROOT;
792 md->writesets[1].md.root = INVALID_WRITESET_ROOT;
793 md->current_writeset = &md->writesets[0];
795 r = create_persistent_data_objects(md, may_format);
804 static void metadata_close(struct era_metadata *md)
806 destroy_persistent_data_objects(md);
810 static bool valid_nr_blocks(dm_block_t n)
813 * dm_bitset restricts us to 2^32. test_bit & co. restrict us
814 * further to 2^31 - 1
816 return n < (1ull << 31);
819 static int metadata_resize(struct era_metadata *md, void *arg)
822 dm_block_t *new_size = arg;
825 if (!valid_nr_blocks(*new_size)) {
826 DMERR("Invalid number of origin blocks %llu",
827 (unsigned long long) *new_size);
831 writeset_free(&md->writesets[0]);
832 writeset_free(&md->writesets[1]);
834 r = writeset_alloc(&md->writesets[0], *new_size);
836 DMERR("%s: writeset_alloc failed for writeset 0", __func__);
840 r = writeset_alloc(&md->writesets[1], *new_size);
842 DMERR("%s: writeset_alloc failed for writeset 1", __func__);
846 value = cpu_to_le32(0u);
847 __dm_bless_for_disk(&value);
848 r = dm_array_resize(&md->era_array_info, md->era_array_root,
849 md->nr_blocks, *new_size,
850 &value, &md->era_array_root);
852 DMERR("%s: dm_array_resize failed", __func__);
856 md->nr_blocks = *new_size;
860 static int metadata_era_archive(struct era_metadata *md)
864 struct writeset_disk value;
866 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
867 &md->current_writeset->md.root);
869 DMERR("%s: dm_bitset_flush failed", __func__);
873 ws_pack(&md->current_writeset->md, &value);
875 keys[0] = md->current_era;
876 __dm_bless_for_disk(&value);
877 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
878 keys, &value, &md->writeset_tree_root);
880 DMERR("%s: couldn't insert writeset into btree", __func__);
881 /* FIXME: fail mode */
885 md->current_writeset->md.root = INVALID_WRITESET_ROOT;
886 md->archived_writesets = true;
891 static struct writeset *next_writeset(struct era_metadata *md)
893 return (md->current_writeset == &md->writesets[0]) ?
894 &md->writesets[1] : &md->writesets[0];
897 static int metadata_new_era(struct era_metadata *md)
900 struct writeset *new_writeset = next_writeset(md);
902 r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks);
904 DMERR("%s: writeset_init failed", __func__);
908 swap_writeset(md, new_writeset);
914 static int metadata_era_rollover(struct era_metadata *md)
918 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
919 r = metadata_era_archive(md);
921 DMERR("%s: metadata_archive_era failed", __func__);
922 /* FIXME: fail mode? */
927 r = metadata_new_era(md);
929 DMERR("%s: new era failed", __func__);
930 /* FIXME: fail mode */
937 static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
943 ws = rcu_dereference(md->current_writeset);
944 r = writeset_marked(ws, block);
950 static int metadata_commit(struct era_metadata *md)
953 struct dm_block *sblock;
955 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
956 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
957 &md->current_writeset->md.root);
959 DMERR("%s: bitset flush failed", __func__);
964 r = dm_tm_pre_commit(md->tm);
966 DMERR("%s: pre commit failed", __func__);
970 r = save_sm_root(md);
972 DMERR("%s: save_sm_root failed", __func__);
976 r = superblock_lock(md, &sblock);
978 DMERR("%s: superblock lock failed", __func__);
982 prepare_superblock(md, dm_block_data(sblock));
984 return dm_tm_commit(md->tm, sblock);
987 static int metadata_checkpoint(struct era_metadata *md)
990 * For now we just rollover, but later I want to put a check in to
991 * avoid this if the filter is still pretty fresh.
993 return metadata_era_rollover(md);
997 * Metadata snapshots allow userland to access era data.
999 static int metadata_take_snap(struct era_metadata *md)
1002 struct dm_block *clone;
1004 if (md->metadata_snap != SUPERBLOCK_LOCATION) {
1005 DMERR("%s: metadata snapshot already exists", __func__);
1009 r = metadata_era_rollover(md);
1011 DMERR("%s: era rollover failed", __func__);
1015 r = metadata_commit(md);
1017 DMERR("%s: pre commit failed", __func__);
1021 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
1023 DMERR("%s: couldn't increment superblock", __func__);
1027 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
1028 &sb_validator, &clone, &inc);
1030 DMERR("%s: couldn't shadow superblock", __func__);
1031 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
1036 r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
1038 DMERR("%s: couldn't inc writeset tree root", __func__);
1039 dm_tm_unlock(md->tm, clone);
1043 r = dm_sm_inc_block(md->sm, md->era_array_root);
1045 DMERR("%s: couldn't inc era tree root", __func__);
1046 dm_sm_dec_block(md->sm, md->writeset_tree_root);
1047 dm_tm_unlock(md->tm, clone);
1051 md->metadata_snap = dm_block_location(clone);
1053 dm_tm_unlock(md->tm, clone);
1058 static int metadata_drop_snap(struct era_metadata *md)
1061 dm_block_t location;
1062 struct dm_block *clone;
1063 struct superblock_disk *disk;
1065 if (md->metadata_snap == SUPERBLOCK_LOCATION) {
1066 DMERR("%s: no snap to drop", __func__);
1070 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
1072 DMERR("%s: couldn't read lock superblock clone", __func__);
1077 * Whatever happens now we'll commit with no record of the metadata
1080 md->metadata_snap = SUPERBLOCK_LOCATION;
1082 disk = dm_block_data(clone);
1083 r = dm_btree_del(&md->writeset_tree_info,
1084 le64_to_cpu(disk->writeset_tree_root));
1086 DMERR("%s: error deleting writeset tree clone", __func__);
1087 dm_tm_unlock(md->tm, clone);
1091 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
1093 DMERR("%s: error deleting era array clone", __func__);
1094 dm_tm_unlock(md->tm, clone);
1098 location = dm_block_location(clone);
1099 dm_tm_unlock(md->tm, clone);
1101 return dm_sm_dec_block(md->sm, location);
1104 struct metadata_stats {
1111 static int metadata_get_stats(struct era_metadata *md, void *ptr)
1114 struct metadata_stats *s = ptr;
1115 dm_block_t nr_free, nr_total;
1117 r = dm_sm_get_nr_free(md->sm, &nr_free);
1119 DMERR("dm_sm_get_nr_free returned %d", r);
1123 r = dm_sm_get_nr_blocks(md->sm, &nr_total);
1125 DMERR("dm_pool_get_metadata_dev_size returned %d", r);
1129 s->used = nr_total - nr_free;
1130 s->total = nr_total;
1131 s->snap = md->metadata_snap;
1132 s->era = md->current_era;
1137 /*----------------------------------------------------------------*/
1140 struct dm_target *ti;
1142 struct dm_dev *metadata_dev;
1143 struct dm_dev *origin_dev;
1145 dm_block_t nr_blocks;
1146 uint32_t sectors_per_block;
1147 int sectors_per_block_shift;
1148 struct era_metadata *md;
1150 struct workqueue_struct *wq;
1151 struct work_struct worker;
1153 spinlock_t deferred_lock;
1154 struct bio_list deferred_bios;
1156 spinlock_t rpc_lock;
1157 struct list_head rpc_calls;
1159 struct digest digest;
1164 struct list_head list;
1166 int (*fn0)(struct era_metadata *);
1167 int (*fn1)(struct era_metadata *, void *);
1171 struct completion complete;
1174 /*----------------------------------------------------------------
1176 *---------------------------------------------------------------*/
1177 static bool block_size_is_power_of_two(struct era *era)
1179 return era->sectors_per_block_shift >= 0;
1182 static dm_block_t get_block(struct era *era, struct bio *bio)
1184 sector_t block_nr = bio->bi_iter.bi_sector;
1186 if (!block_size_is_power_of_two(era))
1187 (void) sector_div(block_nr, era->sectors_per_block);
1189 block_nr >>= era->sectors_per_block_shift;
1194 static void remap_to_origin(struct era *era, struct bio *bio)
1196 bio_set_dev(bio, era->origin_dev->bdev);
1199 /*----------------------------------------------------------------
1201 *--------------------------------------------------------------*/
1202 static void wake_worker(struct era *era)
1204 if (!atomic_read(&era->suspended))
1205 queue_work(era->wq, &era->worker);
1208 static void process_old_eras(struct era *era)
1212 if (!era->digest.step)
1215 r = era->digest.step(era->md, &era->digest);
1217 DMERR("%s: digest step failed, stopping digestion", __func__);
1218 era->digest.step = NULL;
1220 } else if (era->digest.step)
1224 static void process_deferred_bios(struct era *era)
1227 struct bio_list deferred_bios, marked_bios;
1229 bool commit_needed = false;
1230 bool failed = false;
1232 bio_list_init(&deferred_bios);
1233 bio_list_init(&marked_bios);
1235 spin_lock(&era->deferred_lock);
1236 bio_list_merge(&deferred_bios, &era->deferred_bios);
1237 bio_list_init(&era->deferred_bios);
1238 spin_unlock(&era->deferred_lock);
1240 while ((bio = bio_list_pop(&deferred_bios))) {
1241 r = writeset_test_and_set(&era->md->bitset_info,
1242 era->md->current_writeset,
1243 get_block(era, bio));
1246 * This is bad news, we need to rollback.
1252 commit_needed = true;
1254 bio_list_add(&marked_bios, bio);
1257 if (commit_needed) {
1258 r = metadata_commit(era->md);
1264 while ((bio = bio_list_pop(&marked_bios)))
1267 while ((bio = bio_list_pop(&marked_bios)))
1268 submit_bio_noacct(bio);
1271 static void process_rpc_calls(struct era *era)
1274 bool need_commit = false;
1275 struct list_head calls;
1276 struct rpc *rpc, *tmp;
1278 INIT_LIST_HEAD(&calls);
1279 spin_lock(&era->rpc_lock);
1280 list_splice_init(&era->rpc_calls, &calls);
1281 spin_unlock(&era->rpc_lock);
1283 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1284 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1289 r = metadata_commit(era->md);
1291 list_for_each_entry_safe(rpc, tmp, &calls, list)
1295 list_for_each_entry_safe(rpc, tmp, &calls, list)
1296 complete(&rpc->complete);
1299 static void kick_off_digest(struct era *era)
1301 if (era->md->archived_writesets) {
1302 era->md->archived_writesets = false;
1303 metadata_digest_start(era->md, &era->digest);
1307 static void do_work(struct work_struct *ws)
1309 struct era *era = container_of(ws, struct era, worker);
1311 kick_off_digest(era);
1312 process_old_eras(era);
1313 process_deferred_bios(era);
1314 process_rpc_calls(era);
1317 static void defer_bio(struct era *era, struct bio *bio)
1319 spin_lock(&era->deferred_lock);
1320 bio_list_add(&era->deferred_bios, bio);
1321 spin_unlock(&era->deferred_lock);
1327 * Make an rpc call to the worker to change the metadata.
1329 static int perform_rpc(struct era *era, struct rpc *rpc)
1332 init_completion(&rpc->complete);
1334 spin_lock(&era->rpc_lock);
1335 list_add(&rpc->list, &era->rpc_calls);
1336 spin_unlock(&era->rpc_lock);
1339 wait_for_completion(&rpc->complete);
1344 static int in_worker0(struct era *era, int (*fn)(struct era_metadata *))
1350 return perform_rpc(era, &rpc);
1353 static int in_worker1(struct era *era,
1354 int (*fn)(struct era_metadata *, void *), void *arg)
1361 return perform_rpc(era, &rpc);
1364 static void start_worker(struct era *era)
1366 atomic_set(&era->suspended, 0);
1369 static void stop_worker(struct era *era)
1371 atomic_set(&era->suspended, 1);
1372 flush_workqueue(era->wq);
1375 /*----------------------------------------------------------------
1377 *--------------------------------------------------------------*/
1378 static void era_destroy(struct era *era)
1381 metadata_close(era->md);
1384 destroy_workqueue(era->wq);
1386 if (era->origin_dev)
1387 dm_put_device(era->ti, era->origin_dev);
1389 if (era->metadata_dev)
1390 dm_put_device(era->ti, era->metadata_dev);
1395 static dm_block_t calc_nr_blocks(struct era *era)
1397 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1400 static bool valid_block_size(dm_block_t block_size)
1402 bool greater_than_zero = block_size > 0;
1403 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1405 return greater_than_zero && multiple_of_min_block_size;
1409 * <metadata dev> <data dev> <data block size (sectors)>
1411 static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
1416 struct era_metadata *md;
1419 ti->error = "Invalid argument count";
1423 era = kzalloc(sizeof(*era), GFP_KERNEL);
1425 ti->error = "Error allocating era structure";
1431 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
1433 ti->error = "Error opening metadata device";
1438 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev);
1440 ti->error = "Error opening data device";
1445 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1447 ti->error = "Error parsing block size";
1452 r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1454 ti->error = "could not set max io len";
1459 if (!valid_block_size(era->sectors_per_block)) {
1460 ti->error = "Invalid block size";
1464 if (era->sectors_per_block & (era->sectors_per_block - 1))
1465 era->sectors_per_block_shift = -1;
1467 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1469 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1471 ti->error = "Error reading metadata";
1477 era->nr_blocks = calc_nr_blocks(era);
1479 r = metadata_resize(era->md, &era->nr_blocks);
1481 ti->error = "couldn't resize metadata";
1486 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1488 ti->error = "could not create workqueue for metadata object";
1492 INIT_WORK(&era->worker, do_work);
1494 spin_lock_init(&era->deferred_lock);
1495 bio_list_init(&era->deferred_bios);
1497 spin_lock_init(&era->rpc_lock);
1498 INIT_LIST_HEAD(&era->rpc_calls);
1501 ti->num_flush_bios = 1;
1502 ti->flush_supported = true;
1504 ti->num_discard_bios = 1;
1509 static void era_dtr(struct dm_target *ti)
1511 era_destroy(ti->private);
1514 static int era_map(struct dm_target *ti, struct bio *bio)
1516 struct era *era = ti->private;
1517 dm_block_t block = get_block(era, bio);
1520 * All bios get remapped to the origin device. We do this now, but
1521 * it may not get issued until later. Depending on whether the
1522 * block is marked in this era.
1524 remap_to_origin(era, bio);
1527 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1529 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1530 (bio_data_dir(bio) == WRITE) &&
1531 !metadata_current_marked(era->md, block)) {
1532 defer_bio(era, bio);
1533 return DM_MAPIO_SUBMITTED;
1536 return DM_MAPIO_REMAPPED;
1539 static void era_postsuspend(struct dm_target *ti)
1542 struct era *era = ti->private;
1544 r = in_worker0(era, metadata_era_archive);
1546 DMERR("%s: couldn't archive current era", __func__);
1547 /* FIXME: fail mode */
1553 static int era_preresume(struct dm_target *ti)
1556 struct era *era = ti->private;
1557 dm_block_t new_size = calc_nr_blocks(era);
1559 if (era->nr_blocks != new_size) {
1560 r = in_worker1(era, metadata_resize, &new_size);
1564 era->nr_blocks = new_size;
1569 r = in_worker0(era, metadata_era_rollover);
1571 DMERR("%s: metadata_era_rollover failed", __func__);
1581 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1582 * <current era> <held metadata root | '-'>
1584 static void era_status(struct dm_target *ti, status_type_t type,
1585 unsigned status_flags, char *result, unsigned maxlen)
1588 struct era *era = ti->private;
1590 struct metadata_stats stats;
1591 char buf[BDEVNAME_SIZE];
1594 case STATUSTYPE_INFO:
1595 r = in_worker1(era, metadata_get_stats, &stats);
1599 DMEMIT("%u %llu/%llu %u",
1600 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1601 (unsigned long long) stats.used,
1602 (unsigned long long) stats.total,
1603 (unsigned) stats.era);
1605 if (stats.snap != SUPERBLOCK_LOCATION)
1606 DMEMIT(" %llu", stats.snap);
1611 case STATUSTYPE_TABLE:
1612 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1614 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1615 DMEMIT("%s %u", buf, era->sectors_per_block);
1625 static int era_message(struct dm_target *ti, unsigned argc, char **argv,
1626 char *result, unsigned maxlen)
1628 struct era *era = ti->private;
1631 DMERR("incorrect number of message arguments");
1635 if (!strcasecmp(argv[0], "checkpoint"))
1636 return in_worker0(era, metadata_checkpoint);
1638 if (!strcasecmp(argv[0], "take_metadata_snap"))
1639 return in_worker0(era, metadata_take_snap);
1641 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1642 return in_worker0(era, metadata_drop_snap);
1644 DMERR("unsupported message '%s'", argv[0]);
1648 static sector_t get_dev_size(struct dm_dev *dev)
1650 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1653 static int era_iterate_devices(struct dm_target *ti,
1654 iterate_devices_callout_fn fn, void *data)
1656 struct era *era = ti->private;
1657 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1660 static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1662 struct era *era = ti->private;
1663 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1666 * If the system-determined stacked limits are compatible with the
1667 * era device's blocksize (io_opt is a factor) do not override them.
1669 if (io_opt_sectors < era->sectors_per_block ||
1670 do_div(io_opt_sectors, era->sectors_per_block)) {
1671 blk_limits_io_min(limits, 0);
1672 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1676 /*----------------------------------------------------------------*/
1678 static struct target_type era_target = {
1680 .version = {1, 0, 0},
1681 .module = THIS_MODULE,
1685 .postsuspend = era_postsuspend,
1686 .preresume = era_preresume,
1687 .status = era_status,
1688 .message = era_message,
1689 .iterate_devices = era_iterate_devices,
1690 .io_hints = era_io_hints
1693 static int __init dm_era_init(void)
1697 r = dm_register_target(&era_target);
1699 DMERR("era target registration failed: %d", r);
1706 static void __exit dm_era_exit(void)
1708 dm_unregister_target(&era_target);
1711 module_init(dm_era_init);
1712 module_exit(dm_era_exit);
1714 MODULE_DESCRIPTION(DM_NAME " era target");
1715 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1716 MODULE_LICENSE("GPL");