1// SPDX-License-Identifier: GPL-2.0-only
   2#include "dm.h"
   3#include "persistent-data/dm-transaction-manager.h"
   4#include "persistent-data/dm-bitset.h"
   5#include "persistent-data/dm-space-map.h"
   6
   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>
  14
  15#define DM_MSG_PREFIX "era"
  16
  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
  24
  25/*
  26 *--------------------------------------------------------------
  27 * Writeset
  28 *--------------------------------------------------------------
  29 */
  30struct writeset_metadata {
  31	uint32_t nr_bits;
  32	dm_block_t root;
  33};
  34
  35struct writeset {
  36	struct writeset_metadata md;
  37
  38	/*
  39	 * An in core copy of the bits to save constantly doing look ups on
  40	 * disk.
  41	 */
  42	unsigned long *bits;
  43};
  44
  45/*
  46 * This does not free off the on disk bitset as this will normally be done
  47 * after digesting into the era array.
  48 */
  49static void writeset_free(struct writeset *ws)
  50{
  51	vfree(ws->bits);
  52	ws->bits = NULL;
  53}
  54
  55static int setup_on_disk_bitset(struct dm_disk_bitset *info,
  56				unsigned int nr_bits, dm_block_t *root)
  57{
  58	int r;
  59
  60	r = dm_bitset_empty(info, root);
  61	if (r)
  62		return r;
  63
  64	return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
  65}
  66
  67static size_t bitset_size(unsigned int nr_bits)
  68{
  69	return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
  70}
  71
  72/*
  73 * Allocates memory for the in core bitset.
  74 */
  75static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
  76{
 
 
  77	ws->bits = vzalloc(bitset_size(nr_blocks));
  78	if (!ws->bits) {
  79		DMERR("%s: couldn't allocate in memory bitset", __func__);
  80		return -ENOMEM;
  81	}
  82
  83	return 0;
  84}
  85
  86/*
  87 * Wipes the in-core bitset, and creates a new on disk bitset.
  88 */
  89static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws,
  90			 dm_block_t nr_blocks)
  91{
  92	int r;
  93
  94	memset(ws->bits, 0, bitset_size(nr_blocks));
  95
  96	ws->md.nr_bits = nr_blocks;
  97	r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
  98	if (r) {
  99		DMERR("%s: setup_on_disk_bitset failed", __func__);
 100		return r;
 101	}
 102
 103	return 0;
 104}
 105
 106static bool writeset_marked(struct writeset *ws, dm_block_t block)
 107{
 108	return test_bit(block, ws->bits);
 109}
 110
 111static int writeset_marked_on_disk(struct dm_disk_bitset *info,
 112				   struct writeset_metadata *m, dm_block_t block,
 113				   bool *result)
 114{
 115	int r;
 116	dm_block_t old = m->root;
 117
 118	/*
 119	 * The bitset was flushed when it was archived, so we know there'll
 120	 * be no change to the root.
 121	 */
 122	r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
 123	if (r) {
 124		DMERR("%s: dm_bitset_test_bit failed", __func__);
 125		return r;
 126	}
 127
 128	BUG_ON(m->root != old);
 129
 130	return r;
 131}
 132
 133/*
 134 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
 135 */
 136static int writeset_test_and_set(struct dm_disk_bitset *info,
 137				 struct writeset *ws, uint32_t block)
 138{
 139	int r;
 140
 141	if (!test_bit(block, ws->bits)) {
 142		r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
 143		if (r) {
 144			/* FIXME: fail mode */
 145			return r;
 146		}
 147
 148		return 0;
 149	}
 150
 151	return 1;
 152}
 153
 154/*
 155 *--------------------------------------------------------------
 156 * On disk metadata layout
 157 *--------------------------------------------------------------
 158 */
 159#define SPACE_MAP_ROOT_SIZE 128
 160#define UUID_LEN 16
 161
 162struct writeset_disk {
 163	__le32 nr_bits;
 164	__le64 root;
 165} __packed;
 166
 167struct superblock_disk {
 168	__le32 csum;
 169	__le32 flags;
 170	__le64 blocknr;
 171
 172	__u8 uuid[UUID_LEN];
 173	__le64 magic;
 174	__le32 version;
 175
 176	__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 177
 178	__le32 data_block_size;
 179	__le32 metadata_block_size;
 180	__le32 nr_blocks;
 181
 182	__le32 current_era;
 183	struct writeset_disk current_writeset;
 184
 185	/*
 186	 * Only these two fields are valid within the metadata snapshot.
 187	 */
 188	__le64 writeset_tree_root;
 189	__le64 era_array_root;
 190
 191	__le64 metadata_snap;
 192} __packed;
 193
 194/*
 195 *--------------------------------------------------------------
 196 * Superblock validation
 197 *--------------------------------------------------------------
 198 */
 199static void sb_prepare_for_write(const struct dm_block_validator *v,
 200				 struct dm_block *b,
 201				 size_t sb_block_size)
 202{
 203	struct superblock_disk *disk = dm_block_data(b);
 204
 205	disk->blocknr = cpu_to_le64(dm_block_location(b));
 206	disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
 207						sb_block_size - sizeof(__le32),
 208						SUPERBLOCK_CSUM_XOR));
 209}
 210
 211static int check_metadata_version(struct superblock_disk *disk)
 212{
 213	uint32_t metadata_version = le32_to_cpu(disk->version);
 214
 215	if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
 216		DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
 217		      metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
 218		return -EINVAL;
 219	}
 220
 221	return 0;
 222}
 223
 224static int sb_check(const struct dm_block_validator *v,
 225		    struct dm_block *b,
 226		    size_t sb_block_size)
 227{
 228	struct superblock_disk *disk = dm_block_data(b);
 229	__le32 csum_le;
 230
 231	if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
 232		DMERR("%s failed: blocknr %llu: wanted %llu",
 233		      __func__, le64_to_cpu(disk->blocknr),
 234		      (unsigned long long)dm_block_location(b));
 235		return -ENOTBLK;
 236	}
 237
 238	if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
 239		DMERR("%s failed: magic %llu: wanted %llu",
 240		      __func__, le64_to_cpu(disk->magic),
 241		      (unsigned long long) SUPERBLOCK_MAGIC);
 242		return -EILSEQ;
 243	}
 244
 245	csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
 246					     sb_block_size - sizeof(__le32),
 247					     SUPERBLOCK_CSUM_XOR));
 248	if (csum_le != disk->csum) {
 249		DMERR("%s failed: csum %u: wanted %u",
 250		      __func__, le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
 251		return -EILSEQ;
 252	}
 253
 254	return check_metadata_version(disk);
 255}
 256
 257static const struct dm_block_validator sb_validator = {
 258	.name = "superblock",
 259	.prepare_for_write = sb_prepare_for_write,
 260	.check = sb_check
 261};
 262
 263/*
 264 *--------------------------------------------------------------
 265 * Low level metadata handling
 266 *--------------------------------------------------------------
 267 */
 268#define DM_ERA_METADATA_BLOCK_SIZE 4096
 269#define ERA_MAX_CONCURRENT_LOCKS 5
 270
 271struct era_metadata {
 272	struct block_device *bdev;
 273	struct dm_block_manager *bm;
 274	struct dm_space_map *sm;
 275	struct dm_transaction_manager *tm;
 276
 277	dm_block_t block_size;
 278	uint32_t nr_blocks;
 279
 280	uint32_t current_era;
 281
 282	/*
 283	 * We preallocate 2 writesets.  When an era rolls over we
 284	 * switch between them. This means the allocation is done at
 285	 * preresume time, rather than on the io path.
 286	 */
 287	struct writeset writesets[2];
 288	struct writeset *current_writeset;
 289
 290	dm_block_t writeset_tree_root;
 291	dm_block_t era_array_root;
 292
 293	struct dm_disk_bitset bitset_info;
 294	struct dm_btree_info writeset_tree_info;
 295	struct dm_array_info era_array_info;
 296
 297	dm_block_t metadata_snap;
 298
 299	/*
 300	 * A flag that is set whenever a writeset has been archived.
 301	 */
 302	bool archived_writesets;
 303
 304	/*
 305	 * Reading the space map root can fail, so we read it into this
 306	 * buffer before the superblock is locked and updated.
 307	 */
 308	__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 309};
 310
 311static int superblock_read_lock(struct era_metadata *md,
 312				struct dm_block **sblock)
 313{
 314	return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
 315			       &sb_validator, sblock);
 316}
 317
 318static int superblock_lock_zero(struct era_metadata *md,
 319				struct dm_block **sblock)
 320{
 321	return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
 322				     &sb_validator, sblock);
 323}
 324
 325static int superblock_lock(struct era_metadata *md,
 326			   struct dm_block **sblock)
 327{
 328	return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
 329				&sb_validator, sblock);
 330}
 331
 332/* FIXME: duplication with cache and thin */
 333static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
 334{
 335	int r;
 336	unsigned int i;
 337	struct dm_block *b;
 338	__le64 *data_le, zero = cpu_to_le64(0);
 339	unsigned int sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
 340
 341	/*
 342	 * We can't use a validator here - it may be all zeroes.
 343	 */
 344	r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
 345	if (r)
 346		return r;
 347
 348	data_le = dm_block_data(b);
 349	*result = true;
 350	for (i = 0; i < sb_block_size; i++) {
 351		if (data_le[i] != zero) {
 352			*result = false;
 353			break;
 354		}
 355	}
 356
 357	dm_bm_unlock(b);
 358
 359	return 0;
 360}
 361
 362/*----------------------------------------------------------------*/
 363
 364static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
 365{
 366	disk->nr_bits = cpu_to_le32(core->nr_bits);
 367	disk->root = cpu_to_le64(core->root);
 368}
 369
 370static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
 371{
 372	core->nr_bits = le32_to_cpu(disk->nr_bits);
 373	core->root = le64_to_cpu(disk->root);
 374}
 375
 376static void ws_inc(void *context, const void *value, unsigned int count)
 377{
 378	struct era_metadata *md = context;
 379	struct writeset_disk ws_d;
 380	dm_block_t b;
 381	unsigned int i;
 382
 383	for (i = 0; i < count; i++) {
 384		memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
 385		b = le64_to_cpu(ws_d.root);
 386		dm_tm_inc(md->tm, b);
 387	}
 388}
 389
 390static void ws_dec(void *context, const void *value, unsigned int count)
 391{
 392	struct era_metadata *md = context;
 393	struct writeset_disk ws_d;
 394	dm_block_t b;
 395	unsigned int i;
 396
 397	for (i = 0; i < count; i++) {
 398		memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
 399		b = le64_to_cpu(ws_d.root);
 400		dm_bitset_del(&md->bitset_info, b);
 401	}
 402}
 403
 404static int ws_eq(void *context, const void *value1, const void *value2)
 405{
 406	return !memcmp(value1, value2, sizeof(struct writeset_disk));
 407}
 408
 409/*----------------------------------------------------------------*/
 410
 411static void setup_writeset_tree_info(struct era_metadata *md)
 412{
 413	struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
 414
 415	md->writeset_tree_info.tm = md->tm;
 416	md->writeset_tree_info.levels = 1;
 417	vt->context = md;
 418	vt->size = sizeof(struct writeset_disk);
 419	vt->inc = ws_inc;
 420	vt->dec = ws_dec;
 421	vt->equal = ws_eq;
 422}
 423
 424static void setup_era_array_info(struct era_metadata *md)
 
 425{
 426	struct dm_btree_value_type vt;
 427
 428	vt.context = NULL;
 429	vt.size = sizeof(__le32);
 430	vt.inc = NULL;
 431	vt.dec = NULL;
 432	vt.equal = NULL;
 433
 434	dm_array_info_init(&md->era_array_info, md->tm, &vt);
 435}
 436
 437static void setup_infos(struct era_metadata *md)
 438{
 439	dm_disk_bitset_init(md->tm, &md->bitset_info);
 440	setup_writeset_tree_info(md);
 441	setup_era_array_info(md);
 442}
 443
 444/*----------------------------------------------------------------*/
 445
 446static int create_fresh_metadata(struct era_metadata *md)
 447{
 448	int r;
 449
 450	r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
 451				 &md->tm, &md->sm);
 452	if (r < 0) {
 453		DMERR("dm_tm_create_with_sm failed");
 454		return r;
 455	}
 456
 457	setup_infos(md);
 458
 459	r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
 460	if (r) {
 461		DMERR("couldn't create new writeset tree");
 462		goto bad;
 463	}
 464
 465	r = dm_array_empty(&md->era_array_info, &md->era_array_root);
 466	if (r) {
 467		DMERR("couldn't create era array");
 468		goto bad;
 469	}
 470
 471	return 0;
 472
 473bad:
 474	dm_sm_destroy(md->sm);
 475	dm_tm_destroy(md->tm);
 476
 477	return r;
 478}
 479
 480static int save_sm_root(struct era_metadata *md)
 481{
 482	int r;
 483	size_t metadata_len;
 484
 485	r = dm_sm_root_size(md->sm, &metadata_len);
 486	if (r < 0)
 487		return r;
 488
 489	return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
 490			       metadata_len);
 491}
 492
 493static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
 494{
 495	memcpy(&disk->metadata_space_map_root,
 496	       &md->metadata_space_map_root,
 497	       sizeof(md->metadata_space_map_root));
 498}
 499
 500/*
 501 * Writes a superblock, including the static fields that don't get updated
 502 * with every commit (possible optimisation here).  'md' should be fully
 503 * constructed when this is called.
 504 */
 505static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
 506{
 507	disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
 508	disk->flags = cpu_to_le32(0ul);
 509
 510	/* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
 511	memset(disk->uuid, 0, sizeof(disk->uuid));
 512	disk->version = cpu_to_le32(MAX_ERA_VERSION);
 513
 514	copy_sm_root(md, disk);
 515
 516	disk->data_block_size = cpu_to_le32(md->block_size);
 517	disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
 518	disk->nr_blocks = cpu_to_le32(md->nr_blocks);
 519	disk->current_era = cpu_to_le32(md->current_era);
 520
 521	ws_pack(&md->current_writeset->md, &disk->current_writeset);
 522	disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
 523	disk->era_array_root = cpu_to_le64(md->era_array_root);
 524	disk->metadata_snap = cpu_to_le64(md->metadata_snap);
 525}
 526
 527static int write_superblock(struct era_metadata *md)
 528{
 529	int r;
 530	struct dm_block *sblock;
 531	struct superblock_disk *disk;
 532
 533	r = save_sm_root(md);
 534	if (r) {
 535		DMERR("%s: save_sm_root failed", __func__);
 536		return r;
 537	}
 538
 539	r = superblock_lock_zero(md, &sblock);
 540	if (r)
 541		return r;
 542
 543	disk = dm_block_data(sblock);
 544	prepare_superblock(md, disk);
 545
 546	return dm_tm_commit(md->tm, sblock);
 547}
 548
 549/*
 550 * Assumes block_size and the infos are set.
 551 */
 552static int format_metadata(struct era_metadata *md)
 553{
 554	int r;
 555
 556	r = create_fresh_metadata(md);
 557	if (r)
 558		return r;
 559
 560	r = write_superblock(md);
 561	if (r) {
 562		dm_sm_destroy(md->sm);
 563		dm_tm_destroy(md->tm);
 564		return r;
 565	}
 566
 567	return 0;
 568}
 569
 570static int open_metadata(struct era_metadata *md)
 571{
 572	int r;
 573	struct dm_block *sblock;
 574	struct superblock_disk *disk;
 575
 576	r = superblock_read_lock(md, &sblock);
 577	if (r) {
 578		DMERR("couldn't read_lock superblock");
 579		return r;
 580	}
 581
 582	disk = dm_block_data(sblock);
 583
 584	/* Verify the data block size hasn't changed */
 585	if (le32_to_cpu(disk->data_block_size) != md->block_size) {
 586		DMERR("changing the data block size (from %u to %llu) is not supported",
 587		      le32_to_cpu(disk->data_block_size), md->block_size);
 588		r = -EINVAL;
 589		goto bad;
 590	}
 591
 592	r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
 593			       disk->metadata_space_map_root,
 594			       sizeof(disk->metadata_space_map_root),
 595			       &md->tm, &md->sm);
 596	if (r) {
 597		DMERR("dm_tm_open_with_sm failed");
 598		goto bad;
 599	}
 600
 601	setup_infos(md);
 602
 
 603	md->nr_blocks = le32_to_cpu(disk->nr_blocks);
 604	md->current_era = le32_to_cpu(disk->current_era);
 605
 606	ws_unpack(&disk->current_writeset, &md->current_writeset->md);
 607	md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
 608	md->era_array_root = le64_to_cpu(disk->era_array_root);
 609	md->metadata_snap = le64_to_cpu(disk->metadata_snap);
 610	md->archived_writesets = true;
 611
 612	dm_bm_unlock(sblock);
 613
 614	return 0;
 615
 616bad:
 617	dm_bm_unlock(sblock);
 618	return r;
 619}
 620
 621static int open_or_format_metadata(struct era_metadata *md,
 622				   bool may_format)
 623{
 624	int r;
 625	bool unformatted = false;
 626
 627	r = superblock_all_zeroes(md->bm, &unformatted);
 628	if (r)
 629		return r;
 630
 631	if (unformatted)
 632		return may_format ? format_metadata(md) : -EPERM;
 633
 634	return open_metadata(md);
 635}
 636
 637static int create_persistent_data_objects(struct era_metadata *md,
 638					  bool may_format)
 639{
 640	int r;
 641
 642	md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
 643					 ERA_MAX_CONCURRENT_LOCKS);
 644	if (IS_ERR(md->bm)) {
 645		DMERR("could not create block manager");
 646		return PTR_ERR(md->bm);
 647	}
 648
 649	r = open_or_format_metadata(md, may_format);
 650	if (r)
 651		dm_block_manager_destroy(md->bm);
 652
 653	return r;
 654}
 655
 656static void destroy_persistent_data_objects(struct era_metadata *md)
 657{
 658	dm_sm_destroy(md->sm);
 659	dm_tm_destroy(md->tm);
 660	dm_block_manager_destroy(md->bm);
 661}
 662
 663/*
 664 * This waits until all era_map threads have picked up the new filter.
 665 */
 666static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
 667{
 668	rcu_assign_pointer(md->current_writeset, new_writeset);
 669	synchronize_rcu();
 670}
 671
 672/*
 673 *------------------------------------------------------------------------
 674 * Writesets get 'digested' into the main era array.
 675 *
 676 * We're using a coroutine here so the worker thread can do the digestion,
 677 * thus avoiding synchronisation of the metadata.  Digesting a whole
 678 * writeset in one go would cause too much latency.
 679 *------------------------------------------------------------------------
 680 */
 681struct digest {
 682	uint32_t era;
 683	unsigned int nr_bits, current_bit;
 684	struct writeset_metadata writeset;
 685	__le32 value;
 686	struct dm_disk_bitset info;
 687
 688	int (*step)(struct era_metadata *md, struct digest *d);
 689};
 690
 691static int metadata_digest_lookup_writeset(struct era_metadata *md,
 692					   struct digest *d);
 693
 694static int metadata_digest_remove_writeset(struct era_metadata *md,
 695					   struct digest *d)
 696{
 697	int r;
 698	uint64_t key = d->era;
 699
 700	r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
 701			    &key, &md->writeset_tree_root);
 702	if (r) {
 703		DMERR("%s: dm_btree_remove failed", __func__);
 704		return r;
 705	}
 706
 707	d->step = metadata_digest_lookup_writeset;
 708	return 0;
 709}
 710
 711#define INSERTS_PER_STEP 100
 712
 713static int metadata_digest_transcribe_writeset(struct era_metadata *md,
 714					       struct digest *d)
 715{
 716	int r;
 717	bool marked;
 718	unsigned int b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
 719
 720	for (b = d->current_bit; b < e; b++) {
 721		r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
 722		if (r) {
 723			DMERR("%s: writeset_marked_on_disk failed", __func__);
 724			return r;
 725		}
 726
 727		if (!marked)
 728			continue;
 729
 730		__dm_bless_for_disk(&d->value);
 731		r = dm_array_set_value(&md->era_array_info, md->era_array_root,
 732				       b, &d->value, &md->era_array_root);
 733		if (r) {
 734			DMERR("%s: dm_array_set_value failed", __func__);
 735			return r;
 736		}
 737	}
 738
 739	if (b == d->nr_bits)
 740		d->step = metadata_digest_remove_writeset;
 741	else
 742		d->current_bit = b;
 743
 744	return 0;
 745}
 746
 747static int metadata_digest_lookup_writeset(struct era_metadata *md,
 748					   struct digest *d)
 749{
 750	int r;
 751	uint64_t key;
 752	struct writeset_disk disk;
 753
 754	r = dm_btree_find_lowest_key(&md->writeset_tree_info,
 755				     md->writeset_tree_root, &key);
 756	if (r < 0)
 757		return r;
 758
 759	d->era = key;
 760
 761	r = dm_btree_lookup(&md->writeset_tree_info,
 762			    md->writeset_tree_root, &key, &disk);
 763	if (r) {
 764		if (r == -ENODATA) {
 765			d->step = NULL;
 766			return 0;
 767		}
 768
 769		DMERR("%s: dm_btree_lookup failed", __func__);
 770		return r;
 771	}
 772
 773	ws_unpack(&disk, &d->writeset);
 774	d->value = cpu_to_le32(key);
 775
 776	/*
 777	 * We initialise another bitset info to avoid any caching side effects
 778	 * with the previous one.
 779	 */
 780	dm_disk_bitset_init(md->tm, &d->info);
 781
 782	d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
 783	d->current_bit = 0;
 784	d->step = metadata_digest_transcribe_writeset;
 785
 786	return 0;
 787}
 788
 789static int metadata_digest_start(struct era_metadata *md, struct digest *d)
 790{
 791	if (d->step)
 792		return 0;
 793
 794	memset(d, 0, sizeof(*d));
 
 
 
 
 
 
 795	d->step = metadata_digest_lookup_writeset;
 796
 797	return 0;
 798}
 799
 800/*
 801 *-----------------------------------------------------------------
 802 * High level metadata interface.  Target methods should use these,
 803 * and not the lower level ones.
 804 *-----------------------------------------------------------------
 805 */
 806static struct era_metadata *metadata_open(struct block_device *bdev,
 807					  sector_t block_size,
 808					  bool may_format)
 809{
 810	int r;
 811	struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
 812
 813	if (!md)
 814		return NULL;
 815
 816	md->bdev = bdev;
 817	md->block_size = block_size;
 818
 819	md->writesets[0].md.root = INVALID_WRITESET_ROOT;
 820	md->writesets[1].md.root = INVALID_WRITESET_ROOT;
 821	md->current_writeset = &md->writesets[0];
 822
 823	r = create_persistent_data_objects(md, may_format);
 824	if (r) {
 825		kfree(md);
 826		return ERR_PTR(r);
 827	}
 828
 829	return md;
 830}
 831
 832static void metadata_close(struct era_metadata *md)
 833{
 834	writeset_free(&md->writesets[0]);
 835	writeset_free(&md->writesets[1]);
 836	destroy_persistent_data_objects(md);
 837	kfree(md);
 838}
 839
 840static bool valid_nr_blocks(dm_block_t n)
 841{
 842	/*
 843	 * dm_bitset restricts us to 2^32.  test_bit & co. restrict us
 844	 * further to 2^31 - 1
 845	 */
 846	return n < (1ull << 31);
 847}
 848
 849static int metadata_resize(struct era_metadata *md, void *arg)
 850{
 851	int r;
 852	dm_block_t *new_size = arg;
 853	__le32 value;
 854
 855	if (!valid_nr_blocks(*new_size)) {
 856		DMERR("Invalid number of origin blocks %llu",
 857		      (unsigned long long) *new_size);
 858		return -EINVAL;
 859	}
 860
 861	writeset_free(&md->writesets[0]);
 862	writeset_free(&md->writesets[1]);
 863
 864	r = writeset_alloc(&md->writesets[0], *new_size);
 865	if (r) {
 866		DMERR("%s: writeset_alloc failed for writeset 0", __func__);
 867		return r;
 868	}
 869
 870	r = writeset_alloc(&md->writesets[1], *new_size);
 871	if (r) {
 872		DMERR("%s: writeset_alloc failed for writeset 1", __func__);
 873		writeset_free(&md->writesets[0]);
 874		return r;
 875	}
 876
 877	value = cpu_to_le32(0u);
 878	__dm_bless_for_disk(&value);
 879	r = dm_array_resize(&md->era_array_info, md->era_array_root,
 880			    md->nr_blocks, *new_size,
 881			    &value, &md->era_array_root);
 882	if (r) {
 883		DMERR("%s: dm_array_resize failed", __func__);
 884		writeset_free(&md->writesets[0]);
 885		writeset_free(&md->writesets[1]);
 886		return r;
 887	}
 888
 889	md->nr_blocks = *new_size;
 890	return 0;
 891}
 892
 893static int metadata_era_archive(struct era_metadata *md)
 894{
 895	int r;
 896	uint64_t keys[1];
 897	struct writeset_disk value;
 898
 899	r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
 900			    &md->current_writeset->md.root);
 901	if (r) {
 902		DMERR("%s: dm_bitset_flush failed", __func__);
 903		return r;
 904	}
 905
 906	ws_pack(&md->current_writeset->md, &value);
 
 907
 908	keys[0] = md->current_era;
 909	__dm_bless_for_disk(&value);
 910	r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
 911			    keys, &value, &md->writeset_tree_root);
 912	if (r) {
 913		DMERR("%s: couldn't insert writeset into btree", __func__);
 914		/* FIXME: fail mode */
 915		return r;
 916	}
 917
 918	md->current_writeset->md.root = INVALID_WRITESET_ROOT;
 919	md->archived_writesets = true;
 920
 921	return 0;
 922}
 923
 924static struct writeset *next_writeset(struct era_metadata *md)
 925{
 926	return (md->current_writeset == &md->writesets[0]) ?
 927		&md->writesets[1] : &md->writesets[0];
 928}
 929
 930static int metadata_new_era(struct era_metadata *md)
 931{
 932	int r;
 933	struct writeset *new_writeset = next_writeset(md);
 934
 935	r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks);
 936	if (r) {
 937		DMERR("%s: writeset_init failed", __func__);
 938		return r;
 939	}
 940
 941	swap_writeset(md, new_writeset);
 942	md->current_era++;
 943
 944	return 0;
 945}
 946
 947static int metadata_era_rollover(struct era_metadata *md)
 948{
 949	int r;
 950
 951	if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
 952		r = metadata_era_archive(md);
 953		if (r) {
 954			DMERR("%s: metadata_archive_era failed", __func__);
 955			/* FIXME: fail mode? */
 956			return r;
 957		}
 958	}
 959
 960	r = metadata_new_era(md);
 961	if (r) {
 962		DMERR("%s: new era failed", __func__);
 963		/* FIXME: fail mode */
 964		return r;
 965	}
 966
 967	return 0;
 968}
 969
 970static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
 971{
 972	bool r;
 973	struct writeset *ws;
 974
 975	rcu_read_lock();
 976	ws = rcu_dereference(md->current_writeset);
 977	r = writeset_marked(ws, block);
 978	rcu_read_unlock();
 979
 980	return r;
 981}
 982
 983static int metadata_commit(struct era_metadata *md)
 984{
 985	int r;
 986	struct dm_block *sblock;
 987
 988	if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
 989		r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
 990				    &md->current_writeset->md.root);
 991		if (r) {
 992			DMERR("%s: bitset flush failed", __func__);
 993			return r;
 994		}
 995	}
 996
 997	r = dm_tm_pre_commit(md->tm);
 998	if (r) {
 999		DMERR("%s: pre commit failed", __func__);
1000		return r;
1001	}
1002
1003	r = save_sm_root(md);
1004	if (r) {
1005		DMERR("%s: save_sm_root failed", __func__);
1006		return r;
1007	}
1008
1009	r = superblock_lock(md, &sblock);
1010	if (r) {
1011		DMERR("%s: superblock lock failed", __func__);
1012		return r;
1013	}
1014
1015	prepare_superblock(md, dm_block_data(sblock));
1016
1017	return dm_tm_commit(md->tm, sblock);
1018}
1019
1020static int metadata_checkpoint(struct era_metadata *md)
1021{
1022	/*
1023	 * For now we just rollover, but later I want to put a check in to
1024	 * avoid this if the filter is still pretty fresh.
1025	 */
1026	return metadata_era_rollover(md);
1027}
1028
1029/*
1030 * Metadata snapshots allow userland to access era data.
1031 */
1032static int metadata_take_snap(struct era_metadata *md)
1033{
1034	int r, inc;
1035	struct dm_block *clone;
1036
1037	if (md->metadata_snap != SUPERBLOCK_LOCATION) {
1038		DMERR("%s: metadata snapshot already exists", __func__);
1039		return -EINVAL;
1040	}
1041
1042	r = metadata_era_rollover(md);
1043	if (r) {
1044		DMERR("%s: era rollover failed", __func__);
1045		return r;
1046	}
1047
1048	r = metadata_commit(md);
1049	if (r) {
1050		DMERR("%s: pre commit failed", __func__);
1051		return r;
1052	}
1053
1054	r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
1055	if (r) {
1056		DMERR("%s: couldn't increment superblock", __func__);
1057		return r;
1058	}
1059
1060	r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
1061			       &sb_validator, &clone, &inc);
1062	if (r) {
1063		DMERR("%s: couldn't shadow superblock", __func__);
1064		dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
1065		return r;
1066	}
1067	BUG_ON(!inc);
1068
1069	r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
1070	if (r) {
1071		DMERR("%s: couldn't inc writeset tree root", __func__);
1072		dm_tm_unlock(md->tm, clone);
1073		return r;
1074	}
1075
1076	r = dm_sm_inc_block(md->sm, md->era_array_root);
1077	if (r) {
1078		DMERR("%s: couldn't inc era tree root", __func__);
1079		dm_sm_dec_block(md->sm, md->writeset_tree_root);
1080		dm_tm_unlock(md->tm, clone);
1081		return r;
1082	}
1083
1084	md->metadata_snap = dm_block_location(clone);
1085
1086	dm_tm_unlock(md->tm, clone);
1087
1088	return 0;
1089}
1090
1091static int metadata_drop_snap(struct era_metadata *md)
1092{
1093	int r;
1094	dm_block_t location;
1095	struct dm_block *clone;
1096	struct superblock_disk *disk;
1097
1098	if (md->metadata_snap == SUPERBLOCK_LOCATION) {
1099		DMERR("%s: no snap to drop", __func__);
1100		return -EINVAL;
1101	}
1102
1103	r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
1104	if (r) {
1105		DMERR("%s: couldn't read lock superblock clone", __func__);
1106		return r;
1107	}
1108
1109	/*
1110	 * Whatever happens now we'll commit with no record of the metadata
1111	 * snap.
1112	 */
1113	md->metadata_snap = SUPERBLOCK_LOCATION;
1114
1115	disk = dm_block_data(clone);
1116	r = dm_btree_del(&md->writeset_tree_info,
1117			 le64_to_cpu(disk->writeset_tree_root));
1118	if (r) {
1119		DMERR("%s: error deleting writeset tree clone", __func__);
1120		dm_tm_unlock(md->tm, clone);
1121		return r;
1122	}
1123
1124	r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
1125	if (r) {
1126		DMERR("%s: error deleting era array clone", __func__);
1127		dm_tm_unlock(md->tm, clone);
1128		return r;
1129	}
1130
1131	location = dm_block_location(clone);
1132	dm_tm_unlock(md->tm, clone);
1133
1134	return dm_sm_dec_block(md->sm, location);
1135}
1136
1137struct metadata_stats {
1138	dm_block_t used;
1139	dm_block_t total;
1140	dm_block_t snap;
1141	uint32_t era;
1142};
1143
1144static int metadata_get_stats(struct era_metadata *md, void *ptr)
1145{
1146	int r;
1147	struct metadata_stats *s = ptr;
1148	dm_block_t nr_free, nr_total;
1149
1150	r = dm_sm_get_nr_free(md->sm, &nr_free);
1151	if (r) {
1152		DMERR("dm_sm_get_nr_free returned %d", r);
1153		return r;
1154	}
1155
1156	r = dm_sm_get_nr_blocks(md->sm, &nr_total);
1157	if (r) {
1158		DMERR("dm_pool_get_metadata_dev_size returned %d", r);
1159		return r;
1160	}
1161
1162	s->used = nr_total - nr_free;
1163	s->total = nr_total;
1164	s->snap = md->metadata_snap;
1165	s->era = md->current_era;
1166
1167	return 0;
1168}
1169
1170/*----------------------------------------------------------------*/
1171
1172struct era {
1173	struct dm_target *ti;
 
1174
1175	struct dm_dev *metadata_dev;
1176	struct dm_dev *origin_dev;
1177
1178	dm_block_t nr_blocks;
1179	uint32_t sectors_per_block;
1180	int sectors_per_block_shift;
1181	struct era_metadata *md;
1182
1183	struct workqueue_struct *wq;
1184	struct work_struct worker;
1185
1186	spinlock_t deferred_lock;
1187	struct bio_list deferred_bios;
1188
1189	spinlock_t rpc_lock;
1190	struct list_head rpc_calls;
1191
1192	struct digest digest;
1193	atomic_t suspended;
1194};
1195
1196struct rpc {
1197	struct list_head list;
1198
1199	int (*fn0)(struct era_metadata *md);
1200	int (*fn1)(struct era_metadata *md, void *ref);
1201	void *arg;
1202	int result;
1203
1204	struct completion complete;
1205};
1206
1207/*
1208 *---------------------------------------------------------------
1209 * Remapping.
1210 *---------------------------------------------------------------
1211 */
1212static bool block_size_is_power_of_two(struct era *era)
1213{
1214	return era->sectors_per_block_shift >= 0;
1215}
1216
1217static dm_block_t get_block(struct era *era, struct bio *bio)
1218{
1219	sector_t block_nr = bio->bi_iter.bi_sector;
1220
1221	if (!block_size_is_power_of_two(era))
1222		(void) sector_div(block_nr, era->sectors_per_block);
1223	else
1224		block_nr >>= era->sectors_per_block_shift;
1225
1226	return block_nr;
1227}
1228
1229static void remap_to_origin(struct era *era, struct bio *bio)
1230{
1231	bio_set_dev(bio, era->origin_dev->bdev);
1232}
1233
1234/*
1235 *--------------------------------------------------------------
1236 * Worker thread
1237 *--------------------------------------------------------------
1238 */
1239static void wake_worker(struct era *era)
1240{
1241	if (!atomic_read(&era->suspended))
1242		queue_work(era->wq, &era->worker);
1243}
1244
1245static void process_old_eras(struct era *era)
1246{
1247	int r;
1248
1249	if (!era->digest.step)
1250		return;
1251
1252	r = era->digest.step(era->md, &era->digest);
1253	if (r < 0) {
1254		DMERR("%s: digest step failed, stopping digestion", __func__);
1255		era->digest.step = NULL;
1256
1257	} else if (era->digest.step)
1258		wake_worker(era);
1259}
1260
1261static void process_deferred_bios(struct era *era)
1262{
1263	int r;
1264	struct bio_list deferred_bios, marked_bios;
1265	struct bio *bio;
1266	struct blk_plug plug;
1267	bool commit_needed = false;
1268	bool failed = false;
1269	struct writeset *ws = era->md->current_writeset;
1270
1271	bio_list_init(&deferred_bios);
1272	bio_list_init(&marked_bios);
1273
1274	spin_lock(&era->deferred_lock);
1275	bio_list_merge_init(&deferred_bios, &era->deferred_bios);
 
1276	spin_unlock(&era->deferred_lock);
1277
1278	if (bio_list_empty(&deferred_bios))
1279		return;
1280
1281	while ((bio = bio_list_pop(&deferred_bios))) {
1282		r = writeset_test_and_set(&era->md->bitset_info, ws,
 
1283					  get_block(era, bio));
1284		if (r < 0) {
1285			/*
1286			 * This is bad news, we need to rollback.
1287			 * FIXME: finish.
1288			 */
1289			failed = true;
 
1290		} else if (r == 0)
1291			commit_needed = true;
1292
1293		bio_list_add(&marked_bios, bio);
1294	}
1295
1296	if (commit_needed) {
1297		r = metadata_commit(era->md);
1298		if (r)
1299			failed = true;
1300	}
1301
1302	if (failed)
1303		while ((bio = bio_list_pop(&marked_bios)))
1304			bio_io_error(bio);
1305	else {
1306		blk_start_plug(&plug);
1307		while ((bio = bio_list_pop(&marked_bios))) {
1308			/*
1309			 * Only update the in-core writeset if the on-disk one
1310			 * was updated too.
1311			 */
1312			if (commit_needed)
1313				set_bit(get_block(era, bio), ws->bits);
1314			submit_bio_noacct(bio);
1315		}
1316		blk_finish_plug(&plug);
1317	}
1318}
1319
1320static void process_rpc_calls(struct era *era)
1321{
1322	int r;
1323	bool need_commit = false;
1324	struct list_head calls;
1325	struct rpc *rpc, *tmp;
1326
1327	INIT_LIST_HEAD(&calls);
1328	spin_lock(&era->rpc_lock);
1329	list_splice_init(&era->rpc_calls, &calls);
1330	spin_unlock(&era->rpc_lock);
1331
1332	list_for_each_entry_safe(rpc, tmp, &calls, list) {
1333		rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1334		need_commit = true;
1335	}
1336
1337	if (need_commit) {
1338		r = metadata_commit(era->md);
1339		if (r)
1340			list_for_each_entry_safe(rpc, tmp, &calls, list)
1341				rpc->result = r;
1342	}
1343
1344	list_for_each_entry_safe(rpc, tmp, &calls, list)
1345		complete(&rpc->complete);
1346}
1347
1348static void kick_off_digest(struct era *era)
1349{
1350	if (era->md->archived_writesets) {
1351		era->md->archived_writesets = false;
1352		metadata_digest_start(era->md, &era->digest);
1353	}
1354}
1355
1356static void do_work(struct work_struct *ws)
1357{
1358	struct era *era = container_of(ws, struct era, worker);
1359
1360	kick_off_digest(era);
1361	process_old_eras(era);
1362	process_deferred_bios(era);
1363	process_rpc_calls(era);
1364}
1365
1366static void defer_bio(struct era *era, struct bio *bio)
1367{
1368	spin_lock(&era->deferred_lock);
1369	bio_list_add(&era->deferred_bios, bio);
1370	spin_unlock(&era->deferred_lock);
1371
1372	wake_worker(era);
1373}
1374
1375/*
1376 * Make an rpc call to the worker to change the metadata.
1377 */
1378static int perform_rpc(struct era *era, struct rpc *rpc)
1379{
1380	rpc->result = 0;
1381	init_completion(&rpc->complete);
1382
1383	spin_lock(&era->rpc_lock);
1384	list_add(&rpc->list, &era->rpc_calls);
1385	spin_unlock(&era->rpc_lock);
1386
1387	wake_worker(era);
1388	wait_for_completion(&rpc->complete);
1389
1390	return rpc->result;
1391}
1392
1393static int in_worker0(struct era *era, int (*fn)(struct era_metadata *md))
1394{
1395	struct rpc rpc;
1396
1397	rpc.fn0 = fn;
1398	rpc.fn1 = NULL;
1399
1400	return perform_rpc(era, &rpc);
1401}
1402
1403static int in_worker1(struct era *era,
1404		      int (*fn)(struct era_metadata *md, void *ref), void *arg)
1405{
1406	struct rpc rpc;
1407
1408	rpc.fn0 = NULL;
1409	rpc.fn1 = fn;
1410	rpc.arg = arg;
1411
1412	return perform_rpc(era, &rpc);
1413}
1414
1415static void start_worker(struct era *era)
1416{
1417	atomic_set(&era->suspended, 0);
1418}
1419
1420static void stop_worker(struct era *era)
1421{
1422	atomic_set(&era->suspended, 1);
1423	drain_workqueue(era->wq);
1424}
1425
1426/*
1427 *--------------------------------------------------------------
1428 * Target methods
1429 *--------------------------------------------------------------
1430 */
 
 
 
 
 
 
 
 
 
 
 
1431static void era_destroy(struct era *era)
1432{
1433	if (era->md)
1434		metadata_close(era->md);
1435
1436	if (era->wq)
1437		destroy_workqueue(era->wq);
1438
1439	if (era->origin_dev)
1440		dm_put_device(era->ti, era->origin_dev);
1441
1442	if (era->metadata_dev)
1443		dm_put_device(era->ti, era->metadata_dev);
1444
1445	kfree(era);
1446}
1447
1448static dm_block_t calc_nr_blocks(struct era *era)
1449{
1450	return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1451}
1452
1453static bool valid_block_size(dm_block_t block_size)
1454{
1455	bool greater_than_zero = block_size > 0;
1456	bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1457
1458	return greater_than_zero && multiple_of_min_block_size;
1459}
1460
1461/*
1462 * <metadata dev> <data dev> <data block size (sectors)>
1463 */
1464static int era_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1465{
1466	int r;
1467	char dummy;
1468	struct era *era;
1469	struct era_metadata *md;
1470
1471	if (argc != 3) {
1472		ti->error = "Invalid argument count";
1473		return -EINVAL;
1474	}
1475
1476	era = kzalloc(sizeof(*era), GFP_KERNEL);
1477	if (!era) {
1478		ti->error = "Error allocating era structure";
1479		return -ENOMEM;
1480	}
1481
1482	era->ti = ti;
1483
1484	r = dm_get_device(ti, argv[0], BLK_OPEN_READ | BLK_OPEN_WRITE,
1485			  &era->metadata_dev);
1486	if (r) {
1487		ti->error = "Error opening metadata device";
1488		era_destroy(era);
1489		return -EINVAL;
1490	}
1491
1492	r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE,
1493			  &era->origin_dev);
1494	if (r) {
1495		ti->error = "Error opening data device";
1496		era_destroy(era);
1497		return -EINVAL;
1498	}
1499
1500	r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1501	if (r != 1) {
1502		ti->error = "Error parsing block size";
1503		era_destroy(era);
1504		return -EINVAL;
1505	}
1506
1507	r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1508	if (r) {
1509		ti->error = "could not set max io len";
1510		era_destroy(era);
1511		return -EINVAL;
1512	}
1513
1514	if (!valid_block_size(era->sectors_per_block)) {
1515		ti->error = "Invalid block size";
1516		era_destroy(era);
1517		return -EINVAL;
1518	}
1519	if (era->sectors_per_block & (era->sectors_per_block - 1))
1520		era->sectors_per_block_shift = -1;
1521	else
1522		era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1523
1524	md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1525	if (IS_ERR(md)) {
1526		ti->error = "Error reading metadata";
1527		era_destroy(era);
1528		return PTR_ERR(md);
1529	}
1530	era->md = md;
1531
 
 
 
 
 
 
 
 
 
1532	era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1533	if (!era->wq) {
1534		ti->error = "could not create workqueue for metadata object";
1535		era_destroy(era);
1536		return -ENOMEM;
1537	}
1538	INIT_WORK(&era->worker, do_work);
1539
1540	spin_lock_init(&era->deferred_lock);
1541	bio_list_init(&era->deferred_bios);
1542
1543	spin_lock_init(&era->rpc_lock);
1544	INIT_LIST_HEAD(&era->rpc_calls);
1545
1546	ti->private = era;
1547	ti->num_flush_bios = 1;
1548	ti->flush_supported = true;
1549
1550	ti->num_discard_bios = 1;
 
 
1551
1552	return 0;
1553}
1554
1555static void era_dtr(struct dm_target *ti)
1556{
1557	era_destroy(ti->private);
1558}
1559
1560static int era_map(struct dm_target *ti, struct bio *bio)
1561{
1562	struct era *era = ti->private;
1563	dm_block_t block = get_block(era, bio);
1564
1565	/*
1566	 * All bios get remapped to the origin device.  We do this now, but
1567	 * it may not get issued until later.  Depending on whether the
1568	 * block is marked in this era.
1569	 */
1570	remap_to_origin(era, bio);
1571
1572	/*
1573	 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1574	 */
1575	if (!(bio->bi_opf & REQ_PREFLUSH) &&
1576	    (bio_data_dir(bio) == WRITE) &&
1577	    !metadata_current_marked(era->md, block)) {
1578		defer_bio(era, bio);
1579		return DM_MAPIO_SUBMITTED;
1580	}
1581
1582	return DM_MAPIO_REMAPPED;
1583}
1584
1585static void era_postsuspend(struct dm_target *ti)
1586{
1587	int r;
1588	struct era *era = ti->private;
1589
1590	r = in_worker0(era, metadata_era_archive);
1591	if (r) {
1592		DMERR("%s: couldn't archive current era", __func__);
1593		/* FIXME: fail mode */
1594	}
1595
1596	stop_worker(era);
1597
1598	r = metadata_commit(era->md);
1599	if (r) {
1600		DMERR("%s: metadata_commit failed", __func__);
1601		/* FIXME: fail mode */
1602	}
1603}
1604
1605static int era_preresume(struct dm_target *ti)
1606{
1607	int r;
1608	struct era *era = ti->private;
1609	dm_block_t new_size = calc_nr_blocks(era);
1610
1611	if (era->nr_blocks != new_size) {
1612		r = metadata_resize(era->md, &new_size);
1613		if (r) {
1614			DMERR("%s: metadata_resize failed", __func__);
1615			return r;
1616		}
1617
1618		r = metadata_commit(era->md);
1619		if (r) {
1620			DMERR("%s: metadata_commit failed", __func__);
1621			return r;
1622		}
1623
1624		era->nr_blocks = new_size;
1625	}
1626
1627	start_worker(era);
1628
1629	r = in_worker0(era, metadata_era_rollover);
1630	if (r) {
1631		DMERR("%s: metadata_era_rollover failed", __func__);
1632		return r;
1633	}
1634
1635	return 0;
1636}
1637
1638/*
1639 * Status format:
1640 *
1641 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1642 * <current era> <held metadata root | '-'>
1643 */
1644static void era_status(struct dm_target *ti, status_type_t type,
1645		       unsigned int status_flags, char *result, unsigned int maxlen)
1646{
1647	int r;
1648	struct era *era = ti->private;
1649	ssize_t sz = 0;
1650	struct metadata_stats stats;
1651	char buf[BDEVNAME_SIZE];
1652
1653	switch (type) {
1654	case STATUSTYPE_INFO:
1655		r = in_worker1(era, metadata_get_stats, &stats);
1656		if (r)
1657			goto err;
1658
1659		DMEMIT("%u %llu/%llu %u",
1660		       (unsigned int) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1661		       (unsigned long long) stats.used,
1662		       (unsigned long long) stats.total,
1663		       (unsigned int) stats.era);
1664
1665		if (stats.snap != SUPERBLOCK_LOCATION)
1666			DMEMIT(" %llu", stats.snap);
1667		else
1668			DMEMIT(" -");
1669		break;
1670
1671	case STATUSTYPE_TABLE:
1672		format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1673		DMEMIT("%s ", buf);
1674		format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1675		DMEMIT("%s %u", buf, era->sectors_per_block);
1676		break;
1677
1678	case STATUSTYPE_IMA:
1679		*result = '\0';
1680		break;
1681	}
1682
1683	return;
1684
1685err:
1686	DMEMIT("Error");
1687}
1688
1689static int era_message(struct dm_target *ti, unsigned int argc, char **argv,
1690		       char *result, unsigned int maxlen)
1691{
1692	struct era *era = ti->private;
1693
1694	if (argc != 1) {
1695		DMERR("incorrect number of message arguments");
1696		return -EINVAL;
1697	}
1698
1699	if (!strcasecmp(argv[0], "checkpoint"))
1700		return in_worker0(era, metadata_checkpoint);
1701
1702	if (!strcasecmp(argv[0], "take_metadata_snap"))
1703		return in_worker0(era, metadata_take_snap);
1704
1705	if (!strcasecmp(argv[0], "drop_metadata_snap"))
1706		return in_worker0(era, metadata_drop_snap);
1707
1708	DMERR("unsupported message '%s'", argv[0]);
1709	return -EINVAL;
1710}
1711
1712static sector_t get_dev_size(struct dm_dev *dev)
1713{
1714	return bdev_nr_sectors(dev->bdev);
1715}
1716
1717static int era_iterate_devices(struct dm_target *ti,
1718			       iterate_devices_callout_fn fn, void *data)
1719{
1720	struct era *era = ti->private;
1721
1722	return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1723}
1724
1725static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1726{
1727	struct era *era = ti->private;
1728	uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1729
1730	/*
1731	 * If the system-determined stacked limits are compatible with the
1732	 * era device's blocksize (io_opt is a factor) do not override them.
1733	 */
1734	if (io_opt_sectors < era->sectors_per_block ||
1735	    do_div(io_opt_sectors, era->sectors_per_block)) {
1736		limits->io_min = 0;
1737		limits->io_opt = era->sectors_per_block << SECTOR_SHIFT;
1738	}
1739}
1740
1741/*----------------------------------------------------------------*/
1742
1743static struct target_type era_target = {
1744	.name = "era",
1745	.version = {1, 0, 0},
1746	.module = THIS_MODULE,
1747	.ctr = era_ctr,
1748	.dtr = era_dtr,
1749	.map = era_map,
1750	.postsuspend = era_postsuspend,
1751	.preresume = era_preresume,
1752	.status = era_status,
1753	.message = era_message,
1754	.iterate_devices = era_iterate_devices,
1755	.io_hints = era_io_hints
1756};
1757module_dm(era);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1758
1759MODULE_DESCRIPTION(DM_NAME " era target");
1760MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1761MODULE_LICENSE("GPL");