drivers/md/dm-log.c

   1 /*
   2  * Copyright (C) 2003 Sistina Software
   3  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the LGPL.
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/slab.h>
  10 #include <linux/module.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/dm-io.h>
  13 #include <linux/dm-dirty-log.h>
  14
  15 #include <linux/device-mapper.h>
  16
  17 #define DM_MSG_PREFIX "dirty region log"
  18
  19 static LIST_HEAD(_log_types);
  20 static DEFINE_SPINLOCK(_lock);
  21
  22 static struct dm_dirty_log_type *__find_dirty_log_type(const char *name)
  23 {
  24         struct dm_dirty_log_type *log_type;
  25
  26         list_for_each_entry(log_type, &_log_types, list)
  27                 if (!strcmp(name, log_type->name))
  28                         return log_type;
  29
  30         return NULL;
  31 }
  32
  33 static struct dm_dirty_log_type *_get_dirty_log_type(const char *name)
  34 {
  35         struct dm_dirty_log_type *log_type;
  36
  37         spin_lock(&_lock);
  38
  39         log_type = __find_dirty_log_type(name);
  40         if (log_type && !try_module_get(log_type->module))
  41                 log_type = NULL;
  42
  43         spin_unlock(&_lock);
  44
  45         return log_type;
  46 }
  47
  48 /*
  49  * get_type
  50  * @type_name
  51  *
  52  * Attempt to retrieve the dm_dirty_log_type by name.  If not already
  53  * available, attempt to load the appropriate module.
  54  *
  55  * Log modules are named "dm-log-" followed by the 'type_name'.
  56  * Modules may contain multiple types.
  57  * This function will first try the module "dm-log-<type_name>",
  58  * then truncate 'type_name' on the last '-' and try again.
  59  *
  60  * For example, if type_name was "clustered-disk", it would search
  61  * 'dm-log-clustered-disk' then 'dm-log-clustered'.
  62  *
  63  * Returns: dirty_log_type* on success, NULL on failure
  64  */
  65 static struct dm_dirty_log_type *get_type(const char *type_name)
  66 {
  67         char *p, *type_name_dup;
  68         struct dm_dirty_log_type *log_type;
  69
  70         if (!type_name)
  71                 return NULL;
  72
  73         log_type = _get_dirty_log_type(type_name);
  74         if (log_type)
  75                 return log_type;
  76
  77         type_name_dup = kstrdup(type_name, GFP_KERNEL);
  78         if (!type_name_dup) {
  79                 DMWARN("No memory left to attempt log module load for \"%s\"",
  80                        type_name);
  81                 return NULL;
  82         }
  83
  84         while (request_module("dm-log-%s", type_name_dup) ||
  85                !(log_type = _get_dirty_log_type(type_name))) {
  86                 p = strrchr(type_name_dup, '-');
  87                 if (!p)
  88                         break;
  89                 p[0] = '\0';
  90         }
  91
  92         if (!log_type)
  93                 DMWARN("Module for logging type \"%s\" not found.", type_name);
  94
  95         kfree(type_name_dup);
  96
  97         return log_type;
  98 }
  99
 100 static void put_type(struct dm_dirty_log_type *type)
 101 {
 102         if (!type)
 103                 return;
 104
 105         spin_lock(&_lock);
 106         if (!__find_dirty_log_type(type->name))
 107                 goto out;
 108
 109         module_put(type->module);
 110
 111 out:
 112         spin_unlock(&_lock);
 113 }
 114
 115 int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
 116 {
 117         int r = 0;
 118
 119         spin_lock(&_lock);
 120         if (!__find_dirty_log_type(type->name))
 121                 list_add(&type->list, &_log_types);
 122         else
 123                 r = -EEXIST;
 124         spin_unlock(&_lock);
 125
 126         return r;
 127 }
 128 EXPORT_SYMBOL(dm_dirty_log_type_register);
 129
 130 int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
 131 {
 132         spin_lock(&_lock);
 133
 134         if (!__find_dirty_log_type(type->name)) {
 135                 spin_unlock(&_lock);
 136                 return -EINVAL;
 137         }
 138
 139         list_del(&type->list);
 140
 141         spin_unlock(&_lock);
 142
 143         return 0;
 144 }
 145 EXPORT_SYMBOL(dm_dirty_log_type_unregister);
 146
 147 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
 148                         struct dm_target *ti,
 149                         int (*flush_callback_fn)(struct dm_target *ti),
 150                         unsigned int argc, char **argv)
 151 {
 152         struct dm_dirty_log_type *type;
 153         struct dm_dirty_log *log;
 154
 155         log = kmalloc(sizeof(*log), GFP_KERNEL);
 156         if (!log)
 157                 return NULL;
 158
 159         type = get_type(type_name);
 160         if (!type) {
 161                 kfree(log);
 162                 return NULL;
 163         }
 164
 165         log->flush_callback_fn = flush_callback_fn;
 166         log->type = type;
 167         if (type->ctr(log, ti, argc, argv)) {
 168                 kfree(log);
 169                 put_type(type);
 170                 return NULL;
 171         }
 172
 173         return log;
 174 }
 175 EXPORT_SYMBOL(dm_dirty_log_create);
 176
 177 void dm_dirty_log_destroy(struct dm_dirty_log *log)
 178 {
 179         log->type->dtr(log);
 180         put_type(log->type);
 181         kfree(log);
 182 }
 183 EXPORT_SYMBOL(dm_dirty_log_destroy);
 184
 185 /*-----------------------------------------------------------------
 186  * Persistent and core logs share a lot of their implementation.
 187  * FIXME: need a reload method to be called from a resume
 188  *---------------------------------------------------------------*/
 189 /*
 190  * Magic for persistent mirrors: "MiRr"
 191  */
 192 #define MIRROR_MAGIC 0x4D695272
 193
 194 /*
 195  * The on-disk version of the metadata.
 196  */
 197 #define MIRROR_DISK_VERSION 2
 198 #define LOG_OFFSET 2
 199
 200 struct log_header_disk {
 201         __le32 magic;
 202
 203         /*
 204          * Simple, incrementing version. no backward
 205          * compatibility.
 206          */
 207         __le32 version;
 208         __le64 nr_regions;
 209 } __packed;
 210
 211 struct log_header_core {
 212         uint32_t magic;
 213         uint32_t version;
 214         uint64_t nr_regions;
 215 };
 216
 217 struct log_c {
 218         struct dm_target *ti;
 219         int touched_dirtied;
 220         int touched_cleaned;
 221         int flush_failed;
 222         uint32_t region_size;
 223         unsigned int region_count;
 224         region_t sync_count;
 225
 226         unsigned bitset_uint32_count;
 227         uint32_t *clean_bits;
 228         uint32_t *sync_bits;
 229         uint32_t *recovering_bits;      /* FIXME: this seems excessive */
 230
 231         int sync_search;
 232
 233         /* Resync flag */
 234         enum sync {
 235                 DEFAULTSYNC,    /* Synchronize if necessary */
 236                 NOSYNC,         /* Devices known to be already in sync */
 237                 FORCESYNC,      /* Force a sync to happen */
 238         } sync;
 239
 240         struct dm_io_request io_req;
 241
 242         /*
 243          * Disk log fields
 244          */
 245         int log_dev_failed;
 246         int log_dev_flush_failed;
 247         struct dm_dev *log_dev;
 248         struct log_header_core header;
 249
 250         struct dm_io_region header_location;
 251         struct log_header_disk *disk_header;
 252 };
 253
 254 /*
 255  * The touched member needs to be updated every time we access
 256  * one of the bitsets.
 257  */
 258 static inline int log_test_bit(uint32_t *bs, unsigned bit)
 259 {
 260         return test_bit_le(bit, bs) ? 1 : 0;
 261 }
 262
 263 static inline void log_set_bit(struct log_c *l,
 264                                uint32_t *bs, unsigned bit)
 265 {
 266         __set_bit_le(bit, bs);
 267         l->touched_cleaned = 1;
 268 }
 269
 270 static inline void log_clear_bit(struct log_c *l,
 271                                  uint32_t *bs, unsigned bit)
 272 {
 273         __clear_bit_le(bit, bs);
 274         l->touched_dirtied = 1;
 275 }
 276
 277 /*----------------------------------------------------------------
 278  * Header IO
 279  *--------------------------------------------------------------*/
 280 static void header_to_disk(struct log_header_core *core, struct log_header_disk *disk)
 281 {
 282         disk->magic = cpu_to_le32(core->magic);
 283         disk->version = cpu_to_le32(core->version);
 284         disk->nr_regions = cpu_to_le64(core->nr_regions);
 285 }
 286
 287 static void header_from_disk(struct log_header_core *core, struct log_header_disk *disk)
 288 {
 289         core->magic = le32_to_cpu(disk->magic);
 290         core->version = le32_to_cpu(disk->version);
 291         core->nr_regions = le64_to_cpu(disk->nr_regions);
 292 }
 293
 294 static int rw_header(struct log_c *lc, int op)
 295 {
 296         lc->io_req.bi_op = op;
 297         lc->io_req.bi_op_flags = 0;
 298
 299         return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
 300 }
 301
 302 static int flush_header(struct log_c *lc)
 303 {
 304         struct dm_io_region null_location = {
 305                 .bdev = lc->header_location.bdev,
 306                 .sector = 0,
 307                 .count = 0,
 308         };
 309
 310         lc->io_req.bi_op = REQ_OP_WRITE;
 311         lc->io_req.bi_op_flags = WRITE_FLUSH;
 312
 313         return dm_io(&lc->io_req, 1, &null_location, NULL);
 314 }
 315
 316 static int read_header(struct log_c *log)
 317 {
 318         int r;
 319
 320         r = rw_header(log, REQ_OP_READ);
 321         if (r)
 322                 return r;
 323
 324         header_from_disk(&log->header, log->disk_header);
 325
 326         /* New log required? */
 327         if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
 328                 log->header.magic = MIRROR_MAGIC;
 329                 log->header.version = MIRROR_DISK_VERSION;
 330                 log->header.nr_regions = 0;
 331         }
 332
 333 #ifdef __LITTLE_ENDIAN
 334         if (log->header.version == 1)
 335                 log->header.version = 2;
 336 #endif
 337
 338         if (log->header.version != MIRROR_DISK_VERSION) {
 339                 DMWARN("incompatible disk log version");
 340                 return -EINVAL;
 341         }
 342
 343         return 0;
 344 }
 345
 346 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
 347 {
 348         if (region_size < 2 || region_size > ti->len)
 349                 return 0;
 350
 351         if (!is_power_of_2(region_size))
 352                 return 0;
 353
 354         return 1;
 355 }
 356
 357 /*----------------------------------------------------------------
 358  * core log constructor/destructor
 359  *
 360  * argv contains region_size followed optionally by [no]sync
 361  *--------------------------------------------------------------*/
 362 #define BYTE_SHIFT 3
 363 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
 364                               unsigned int argc, char **argv,
 365                               struct dm_dev *dev)
 366 {
 367         enum sync sync = DEFAULTSYNC;
 368
 369         struct log_c *lc;
 370         uint32_t region_size;
 371         unsigned int region_count;
 372         size_t bitset_size, buf_size;
 373         int r;
 374         char dummy;
 375
 376         if (argc < 1 || argc > 2) {
 377                 DMWARN("wrong number of arguments to dirty region log");
 378                 return -EINVAL;
 379         }
 380
 381         if (argc > 1) {
 382                 if (!strcmp(argv[1], "sync"))
 383                         sync = FORCESYNC;
 384                 else if (!strcmp(argv[1], "nosync"))
 385                         sync = NOSYNC;
 386                 else {
 387                         DMWARN("unrecognised sync argument to "
 388                                "dirty region log: %s", argv[1]);
 389                         return -EINVAL;
 390                 }
 391         }
 392
 393         if (sscanf(argv[0], "%u%c", &region_size, &dummy) != 1 ||
 394             !_check_region_size(ti, region_size)) {
 395                 DMWARN("invalid region size %s", argv[0]);
 396                 return -EINVAL;
 397         }
 398
 399         region_count = dm_sector_div_up(ti->len, region_size);
 400
 401         lc = kmalloc(sizeof(*lc), GFP_KERNEL);
 402         if (!lc) {
 403                 DMWARN("couldn't allocate core log");
 404                 return -ENOMEM;
 405         }
 406
 407         lc->ti = ti;
 408         lc->touched_dirtied = 0;
 409         lc->touched_cleaned = 0;
 410         lc->flush_failed = 0;
 411         lc->region_size = region_size;
 412         lc->region_count = region_count;
 413         lc->sync = sync;
 414
 415         /*
 416          * Work out how many "unsigned long"s we need to hold the bitset.
 417          */
 418         bitset_size = dm_round_up(region_count,
 419                                   sizeof(*lc->clean_bits) << BYTE_SHIFT);
 420         bitset_size >>= BYTE_SHIFT;
 421
 422         lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
 423
 424         /*
 425          * Disk log?
 426          */
 427         if (!dev) {
 428                 lc->clean_bits = vmalloc(bitset_size);
 429                 if (!lc->clean_bits) {
 430                         DMWARN("couldn't allocate clean bitset");
 431                         kfree(lc);
 432                         return -ENOMEM;
 433                 }
 434                 lc->disk_header = NULL;
 435         } else {
 436                 lc->log_dev = dev;
 437                 lc->log_dev_failed = 0;
 438                 lc->log_dev_flush_failed = 0;
 439                 lc->header_location.bdev = lc->log_dev->bdev;
 440                 lc->header_location.sector = 0;
 441
 442                 /*
 443                  * Buffer holds both header and bitset.
 444                  */
 445                 buf_size =
 446                     dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
 447                                 bdev_logical_block_size(lc->header_location.
 448                                                             bdev));
 449
 450                 if (buf_size > i_size_read(dev->bdev->bd_inode)) {
 451                         DMWARN("log device %s too small: need %llu bytes",
 452                                 dev->name, (unsigned long long)buf_size);
 453                         kfree(lc);
 454                         return -EINVAL;
 455                 }
 456
 457                 lc->header_location.count = buf_size >> SECTOR_SHIFT;
 458
 459                 lc->io_req.mem.type = DM_IO_VMA;
 460                 lc->io_req.notify.fn = NULL;
 461                 lc->io_req.client = dm_io_client_create();
 462                 if (IS_ERR(lc->io_req.client)) {
 463                         r = PTR_ERR(lc->io_req.client);
 464                         DMWARN("couldn't allocate disk io client");
 465                         kfree(lc);
 466                         return r;
 467                 }
 468
 469                 lc->disk_header = vmalloc(buf_size);
 470                 if (!lc->disk_header) {
 471                         DMWARN("couldn't allocate disk log buffer");
 472                         dm_io_client_destroy(lc->io_req.client);
 473                         kfree(lc);
 474                         return -ENOMEM;
 475                 }
 476
 477                 lc->io_req.mem.ptr.vma = lc->disk_header;
 478                 lc->clean_bits = (void *)lc->disk_header +
 479                                  (LOG_OFFSET << SECTOR_SHIFT);
 480         }
 481
 482         memset(lc->clean_bits, -1, bitset_size);
 483
 484         lc->sync_bits = vmalloc(bitset_size);
 485         if (!lc->sync_bits) {
 486                 DMWARN("couldn't allocate sync bitset");
 487                 if (!dev)
 488                         vfree(lc->clean_bits);
 489                 else
 490                         dm_io_client_destroy(lc->io_req.client);
 491                 vfree(lc->disk_header);
 492                 kfree(lc);
 493                 return -ENOMEM;
 494         }
 495         memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
 496         lc->sync_count = (sync == NOSYNC) ? region_count : 0;
 497
 498         lc->recovering_bits = vzalloc(bitset_size);
 499         if (!lc->recovering_bits) {
 500                 DMWARN("couldn't allocate sync bitset");
 501                 vfree(lc->sync_bits);
 502                 if (!dev)
 503                         vfree(lc->clean_bits);
 504                 else
 505                         dm_io_client_destroy(lc->io_req.client);
 506                 vfree(lc->disk_header);
 507                 kfree(lc);
 508                 return -ENOMEM;
 509         }
 510         lc->sync_search = 0;
 511         log->context = lc;
 512
 513         return 0;
 514 }
 515
 516 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 517                     unsigned int argc, char **argv)
 518 {
 519         return create_log_context(log, ti, argc, argv, NULL);
 520 }
 521
 522 static void destroy_log_context(struct log_c *lc)
 523 {
 524         vfree(lc->sync_bits);
 525         vfree(lc->recovering_bits);
 526         kfree(lc);
 527 }
 528
 529 static void core_dtr(struct dm_dirty_log *log)
 530 {
 531         struct log_c *lc = (struct log_c *) log->context;
 532
 533         vfree(lc->clean_bits);
 534         destroy_log_context(lc);
 535 }
 536
 537 /*----------------------------------------------------------------
 538  * disk log constructor/destructor
 539  *
 540  * argv contains log_device region_size followed optionally by [no]sync
 541  *--------------------------------------------------------------*/
 542 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 543                     unsigned int argc, char **argv)
 544 {
 545         int r;
 546         struct dm_dev *dev;
 547
 548         if (argc < 2 || argc > 3) {
 549                 DMWARN("wrong number of arguments to disk dirty region log");
 550                 return -EINVAL;
 551         }
 552
 553         r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
 554         if (r)
 555                 return r;
 556
 557         r = create_log_context(log, ti, argc - 1, argv + 1, dev);
 558         if (r) {
 559                 dm_put_device(ti, dev);
 560                 return r;
 561         }
 562
 563         return 0;
 564 }
 565
 566 static void disk_dtr(struct dm_dirty_log *log)
 567 {
 568         struct log_c *lc = (struct log_c *) log->context;
 569
 570         dm_put_device(lc->ti, lc->log_dev);
 571         vfree(lc->disk_header);
 572         dm_io_client_destroy(lc->io_req.client);
 573         destroy_log_context(lc);
 574 }
 575
 576 static void fail_log_device(struct log_c *lc)
 577 {
 578         if (lc->log_dev_failed)
 579                 return;
 580
 581         lc->log_dev_failed = 1;
 582         dm_table_event(lc->ti->table);
 583 }
 584
 585 static int disk_resume(struct dm_dirty_log *log)
 586 {
 587         int r;
 588         unsigned i;
 589         struct log_c *lc = (struct log_c *) log->context;
 590         size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
 591
 592         /* read the disk header */
 593         r = read_header(lc);
 594         if (r) {
 595                 DMWARN("%s: Failed to read header on dirty region log device",
 596                        lc->log_dev->name);
 597                 fail_log_device(lc);
 598                 /*
 599                  * If the log device cannot be read, we must assume
 600                  * all regions are out-of-sync.  If we simply return
 601                  * here, the state will be uninitialized and could
 602                  * lead us to return 'in-sync' status for regions
 603                  * that are actually 'out-of-sync'.
 604                  */
 605                 lc->header.nr_regions = 0;
 606         }
 607
 608         /* set or clear any new bits -- device has grown */
 609         if (lc->sync == NOSYNC)
 610                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
 611                         /* FIXME: amazingly inefficient */
 612                         log_set_bit(lc, lc->clean_bits, i);
 613         else
 614                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
 615                         /* FIXME: amazingly inefficient */
 616                         log_clear_bit(lc, lc->clean_bits, i);
 617
 618         /* clear any old bits -- device has shrunk */
 619         for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
 620                 log_clear_bit(lc, lc->clean_bits, i);
 621
 622         /* copy clean across to sync */
 623         memcpy(lc->sync_bits, lc->clean_bits, size);
 624         lc->sync_count = memweight(lc->clean_bits,
 625                                 lc->bitset_uint32_count * sizeof(uint32_t));
 626         lc->sync_search = 0;
 627
 628         /* set the correct number of regions in the header */
 629         lc->header.nr_regions = lc->region_count;
 630
 631         header_to_disk(&lc->header, lc->disk_header);
 632
 633         /* write the new header */
 634         r = rw_header(lc, REQ_OP_WRITE);
 635         if (!r) {
 636                 r = flush_header(lc);
 637                 if (r)
 638                         lc->log_dev_flush_failed = 1;
 639         }
 640         if (r) {
 641                 DMWARN("%s: Failed to write header on dirty region log device",
 642                        lc->log_dev->name);
 643                 fail_log_device(lc);
 644         }
 645
 646         return r;
 647 }
 648
 649 static uint32_t core_get_region_size(struct dm_dirty_log *log)
 650 {
 651         struct log_c *lc = (struct log_c *) log->context;
 652         return lc->region_size;
 653 }
 654
 655 static int core_resume(struct dm_dirty_log *log)
 656 {
 657         struct log_c *lc = (struct log_c *) log->context;
 658         lc->sync_search = 0;
 659         return 0;
 660 }
 661
 662 static int core_is_clean(struct dm_dirty_log *log, region_t region)
 663 {
 664         struct log_c *lc = (struct log_c *) log->context;
 665         return log_test_bit(lc->clean_bits, region);
 666 }
 667
 668 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
 669 {
 670         struct log_c *lc = (struct log_c *) log->context;
 671         return log_test_bit(lc->sync_bits, region);
 672 }
 673
 674 static int core_flush(struct dm_dirty_log *log)
 675 {
 676         /* no op */
 677         return 0;
 678 }
 679
 680 static int disk_flush(struct dm_dirty_log *log)
 681 {
 682         int r, i;
 683         struct log_c *lc = log->context;
 684
 685         /* only write if the log has changed */
 686         if (!lc->touched_cleaned && !lc->touched_dirtied)
 687                 return 0;
 688
 689         if (lc->touched_cleaned && log->flush_callback_fn &&
 690             log->flush_callback_fn(lc->ti)) {
 691                 /*
 692                  * At this point it is impossible to determine which
 693                  * regions are clean and which are dirty (without
 694                  * re-reading the log off disk). So mark all of them
 695                  * dirty.
 696                  */
 697                 lc->flush_failed = 1;
 698                 for (i = 0; i < lc->region_count; i++)
 699                         log_clear_bit(lc, lc->clean_bits, i);
 700         }
 701
 702         r = rw_header(lc, REQ_OP_WRITE);
 703         if (r)
 704                 fail_log_device(lc);
 705         else {
 706                 if (lc->touched_dirtied) {
 707                         r = flush_header(lc);
 708                         if (r) {
 709                                 lc->log_dev_flush_failed = 1;
 710                                 fail_log_device(lc);
 711                         } else
 712                                 lc->touched_dirtied = 0;
 713                 }
 714                 lc->touched_cleaned = 0;
 715         }
 716
 717         return r;
 718 }
 719
 720 static void core_mark_region(struct dm_dirty_log *log, region_t region)
 721 {
 722         struct log_c *lc = (struct log_c *) log->context;
 723         log_clear_bit(lc, lc->clean_bits, region);
 724 }
 725
 726 static void core_clear_region(struct dm_dirty_log *log, region_t region)
 727 {
 728         struct log_c *lc = (struct log_c *) log->context;
 729         if (likely(!lc->flush_failed))
 730                 log_set_bit(lc, lc->clean_bits, region);
 731 }
 732
 733 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
 734 {
 735         struct log_c *lc = (struct log_c *) log->context;
 736
 737         if (lc->sync_search >= lc->region_count)
 738                 return 0;
 739
 740         do {
 741                 *region = find_next_zero_bit_le(lc->sync_bits,
 742                                              lc->region_count,
 743                                              lc->sync_search);
 744                 lc->sync_search = *region + 1;
 745
 746                 if (*region >= lc->region_count)
 747                         return 0;
 748
 749         } while (log_test_bit(lc->recovering_bits, *region));
 750
 751         log_set_bit(lc, lc->recovering_bits, *region);
 752         return 1;
 753 }
 754
 755 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
 756                                  int in_sync)
 757 {
 758         struct log_c *lc = (struct log_c *) log->context;
 759
 760         log_clear_bit(lc, lc->recovering_bits, region);
 761         if (in_sync) {
 762                 log_set_bit(lc, lc->sync_bits, region);
 763                 lc->sync_count++;
 764         } else if (log_test_bit(lc->sync_bits, region)) {
 765                 lc->sync_count--;
 766                 log_clear_bit(lc, lc->sync_bits, region);
 767         }
 768 }
 769
 770 static region_t core_get_sync_count(struct dm_dirty_log *log)
 771 {
 772         struct log_c *lc = (struct log_c *) log->context;
 773
 774         return lc->sync_count;
 775 }
 776
 777 #define DMEMIT_SYNC \
 778         if (lc->sync != DEFAULTSYNC) \
 779                 DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
 780
 781 static int core_status(struct dm_dirty_log *log, status_type_t status,
 782                        char *result, unsigned int maxlen)
 783 {
 784         int sz = 0;
 785         struct log_c *lc = log->context;
 786
 787         switch(status) {
 788         case STATUSTYPE_INFO:
 789                 DMEMIT("1 %s", log->type->name);
 790                 break;
 791
 792         case STATUSTYPE_TABLE:
 793                 DMEMIT("%s %u %u ", log->type->name,
 794                        lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
 795                 DMEMIT_SYNC;
 796         }
 797
 798         return sz;
 799 }
 800
 801 static int disk_status(struct dm_dirty_log *log, status_type_t status,
 802                        char *result, unsigned int maxlen)
 803 {
 804         int sz = 0;
 805         struct log_c *lc = log->context;
 806
 807         switch(status) {
 808         case STATUSTYPE_INFO:
 809                 DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
 810                        lc->log_dev_flush_failed ? 'F' :
 811                        lc->log_dev_failed ? 'D' :
 812                        'A');
 813                 break;
 814
 815         case STATUSTYPE_TABLE:
 816                 DMEMIT("%s %u %s %u ", log->type->name,
 817                        lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
 818                        lc->region_size);
 819                 DMEMIT_SYNC;
 820         }
 821
 822         return sz;
 823 }
 824
 825 static struct dm_dirty_log_type _core_type = {
 826         .name = "core",
 827         .module = THIS_MODULE,
 828         .ctr = core_ctr,
 829         .dtr = core_dtr,
 830         .resume = core_resume,
 831         .get_region_size = core_get_region_size,
 832         .is_clean = core_is_clean,
 833         .in_sync = core_in_sync,
 834         .flush = core_flush,
 835         .mark_region = core_mark_region,
 836         .clear_region = core_clear_region,
 837         .get_resync_work = core_get_resync_work,
 838         .set_region_sync = core_set_region_sync,
 839         .get_sync_count = core_get_sync_count,
 840         .status = core_status,
 841 };
 842
 843 static struct dm_dirty_log_type _disk_type = {
 844         .name = "disk",
 845         .module = THIS_MODULE,
 846         .ctr = disk_ctr,
 847         .dtr = disk_dtr,
 848         .postsuspend = disk_flush,
 849         .resume = disk_resume,
 850         .get_region_size = core_get_region_size,
 851         .is_clean = core_is_clean,
 852         .in_sync = core_in_sync,
 853         .flush = disk_flush,
 854         .mark_region = core_mark_region,
 855         .clear_region = core_clear_region,
 856         .get_resync_work = core_get_resync_work,
 857         .set_region_sync = core_set_region_sync,
 858         .get_sync_count = core_get_sync_count,
 859         .status = disk_status,
 860 };
 861
 862 static int __init dm_dirty_log_init(void)
 863 {
 864         int r;
 865
 866         r = dm_dirty_log_type_register(&_core_type);
 867         if (r)
 868                 DMWARN("couldn't register core log");
 869
 870         r = dm_dirty_log_type_register(&_disk_type);
 871         if (r) {
 872                 DMWARN("couldn't register disk type");
 873                 dm_dirty_log_type_unregister(&_core_type);
 874         }
 875
 876         return r;
 877 }
 878
 879 static void __exit dm_dirty_log_exit(void)
 880 {
 881         dm_dirty_log_type_unregister(&_disk_type);
 882         dm_dirty_log_type_unregister(&_core_type);
 883 }
 884
 885 module_init(dm_dirty_log_init);
 886 module_exit(dm_dirty_log_exit);
 887
 888 MODULE_DESCRIPTION(DM_NAME " dirty region log");
 889 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
 890 MODULE_LICENSE("GPL");