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 {
 201         uint32_t magic;
 202
 203         /*
 204          * Simple, incrementing version. no backward
 205          * compatibility.
 206          */
 207         uint32_t version;
 208         sector_t nr_regions;
 209 };
 210
 211 struct log_c {
 212         struct dm_target *ti;
 213         int touched_dirtied;
 214         int touched_cleaned;
 215         int flush_failed;
 216         uint32_t region_size;
 217         unsigned int region_count;
 218         region_t sync_count;
 219
 220         unsigned bitset_uint32_count;
 221         uint32_t *clean_bits;
 222         uint32_t *sync_bits;
 223         uint32_t *recovering_bits;      /* FIXME: this seems excessive */
 224
 225         int sync_search;
 226
 227         /* Resync flag */
 228         enum sync {
 229                 DEFAULTSYNC,    /* Synchronize if necessary */
 230                 NOSYNC,         /* Devices known to be already in sync */
 231                 FORCESYNC,      /* Force a sync to happen */
 232         } sync;
 233
 234         struct dm_io_request io_req;
 235
 236         /*
 237          * Disk log fields
 238          */
 239         int log_dev_failed;
 240         int log_dev_flush_failed;
 241         struct dm_dev *log_dev;
 242         struct log_header header;
 243
 244         struct dm_io_region header_location;
 245         struct log_header *disk_header;
 246 };
 247
 248 /*
 249  * The touched member needs to be updated every time we access
 250  * one of the bitsets.
 251  */
 252 static inline int log_test_bit(uint32_t *bs, unsigned bit)
 253 {
 254         return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;
 255 }
 256
 257 static inline void log_set_bit(struct log_c *l,
 258                                uint32_t *bs, unsigned bit)
 259 {
 260         ext2_set_bit(bit, (unsigned long *) bs);
 261         l->touched_cleaned = 1;
 262 }
 263
 264 static inline void log_clear_bit(struct log_c *l,
 265                                  uint32_t *bs, unsigned bit)
 266 {
 267         ext2_clear_bit(bit, (unsigned long *) bs);
 268         l->touched_dirtied = 1;
 269 }
 270
 271 /*----------------------------------------------------------------
 272  * Header IO
 273  *--------------------------------------------------------------*/
 274 static void header_to_disk(struct log_header *core, struct log_header *disk)
 275 {
 276         disk->magic = cpu_to_le32(core->magic);
 277         disk->version = cpu_to_le32(core->version);
 278         disk->nr_regions = cpu_to_le64(core->nr_regions);
 279 }
 280
 281 static void header_from_disk(struct log_header *core, struct log_header *disk)
 282 {
 283         core->magic = le32_to_cpu(disk->magic);
 284         core->version = le32_to_cpu(disk->version);
 285         core->nr_regions = le64_to_cpu(disk->nr_regions);
 286 }
 287
 288 static int rw_header(struct log_c *lc, int rw)
 289 {
 290         lc->io_req.bi_rw = rw;
 291
 292         return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
 293 }
 294
 295 static int flush_header(struct log_c *lc)
 296 {
 297         struct dm_io_region null_location = {
 298                 .bdev = lc->header_location.bdev,
 299                 .sector = 0,
 300                 .count = 0,
 301         };
 302
 303         lc->io_req.bi_rw = WRITE_BARRIER;
 304
 305         return dm_io(&lc->io_req, 1, &null_location, NULL);
 306 }
 307
 308 static int read_header(struct log_c *log)
 309 {
 310         int r;
 311
 312         r = rw_header(log, READ);
 313         if (r)
 314                 return r;
 315
 316         header_from_disk(&log->header, log->disk_header);
 317
 318         /* New log required? */
 319         if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
 320                 log->header.magic = MIRROR_MAGIC;
 321                 log->header.version = MIRROR_DISK_VERSION;
 322                 log->header.nr_regions = 0;
 323         }
 324
 325 #ifdef __LITTLE_ENDIAN
 326         if (log->header.version == 1)
 327                 log->header.version = 2;
 328 #endif
 329
 330         if (log->header.version != MIRROR_DISK_VERSION) {
 331                 DMWARN("incompatible disk log version");
 332                 return -EINVAL;
 333         }
 334
 335         return 0;
 336 }
 337
 338 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
 339 {
 340         if (region_size < 2 || region_size > ti->len)
 341                 return 0;
 342
 343         if (!is_power_of_2(region_size))
 344                 return 0;
 345
 346         return 1;
 347 }
 348
 349 /*----------------------------------------------------------------
 350  * core log constructor/destructor
 351  *
 352  * argv contains region_size followed optionally by [no]sync
 353  *--------------------------------------------------------------*/
 354 #define BYTE_SHIFT 3
 355 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
 356                               unsigned int argc, char **argv,
 357                               struct dm_dev *dev)
 358 {
 359         enum sync sync = DEFAULTSYNC;
 360
 361         struct log_c *lc;
 362         uint32_t region_size;
 363         unsigned int region_count;
 364         size_t bitset_size, buf_size;
 365         int r;
 366
 367         if (argc < 1 || argc > 2) {
 368                 DMWARN("wrong number of arguments to dirty region log");
 369                 return -EINVAL;
 370         }
 371
 372         if (argc > 1) {
 373                 if (!strcmp(argv[1], "sync"))
 374                         sync = FORCESYNC;
 375                 else if (!strcmp(argv[1], "nosync"))
 376                         sync = NOSYNC;
 377                 else {
 378                         DMWARN("unrecognised sync argument to "
 379                                "dirty region log: %s", argv[1]);
 380                         return -EINVAL;
 381                 }
 382         }
 383
 384         if (sscanf(argv[0], "%u", &region_size) != 1 ||
 385             !_check_region_size(ti, region_size)) {
 386                 DMWARN("invalid region size %s", argv[0]);
 387                 return -EINVAL;
 388         }
 389
 390         region_count = dm_sector_div_up(ti->len, region_size);
 391
 392         lc = kmalloc(sizeof(*lc), GFP_KERNEL);
 393         if (!lc) {
 394                 DMWARN("couldn't allocate core log");
 395                 return -ENOMEM;
 396         }
 397
 398         lc->ti = ti;
 399         lc->touched_dirtied = 0;
 400         lc->touched_cleaned = 0;
 401         lc->flush_failed = 0;
 402         lc->region_size = region_size;
 403         lc->region_count = region_count;
 404         lc->sync = sync;
 405
 406         /*
 407          * Work out how many "unsigned long"s we need to hold the bitset.
 408          */
 409         bitset_size = dm_round_up(region_count,
 410                                   sizeof(*lc->clean_bits) << BYTE_SHIFT);
 411         bitset_size >>= BYTE_SHIFT;
 412
 413         lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
 414
 415         /*
 416          * Disk log?
 417          */
 418         if (!dev) {
 419                 lc->clean_bits = vmalloc(bitset_size);
 420                 if (!lc->clean_bits) {
 421                         DMWARN("couldn't allocate clean bitset");
 422                         kfree(lc);
 423                         return -ENOMEM;
 424                 }
 425                 lc->disk_header = NULL;
 426         } else {
 427                 lc->log_dev = dev;
 428                 lc->log_dev_failed = 0;
 429                 lc->log_dev_flush_failed = 0;
 430                 lc->header_location.bdev = lc->log_dev->bdev;
 431                 lc->header_location.sector = 0;
 432
 433                 /*
 434                  * Buffer holds both header and bitset.
 435                  */
 436                 buf_size =
 437                     dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
 438                                 bdev_logical_block_size(lc->header_location.
 439                                                             bdev));
 440
 441                 if (buf_size > i_size_read(dev->bdev->bd_inode)) {
 442                         DMWARN("log device %s too small: need %llu bytes",
 443                                 dev->name, (unsigned long long)buf_size);
 444                         kfree(lc);
 445                         return -EINVAL;
 446                 }
 447
 448                 lc->header_location.count = buf_size >> SECTOR_SHIFT;
 449
 450                 lc->io_req.mem.type = DM_IO_VMA;
 451                 lc->io_req.notify.fn = NULL;
 452                 lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
 453                                                                    PAGE_SIZE));
 454                 if (IS_ERR(lc->io_req.client)) {
 455                         r = PTR_ERR(lc->io_req.client);
 456                         DMWARN("couldn't allocate disk io client");
 457                         kfree(lc);
 458                         return -ENOMEM;
 459                 }
 460
 461                 lc->disk_header = vmalloc(buf_size);
 462                 if (!lc->disk_header) {
 463                         DMWARN("couldn't allocate disk log buffer");
 464                         dm_io_client_destroy(lc->io_req.client);
 465                         kfree(lc);
 466                         return -ENOMEM;
 467                 }
 468
 469                 lc->io_req.mem.ptr.vma = lc->disk_header;
 470                 lc->clean_bits = (void *)lc->disk_header +
 471                                  (LOG_OFFSET << SECTOR_SHIFT);
 472         }
 473
 474         memset(lc->clean_bits, -1, bitset_size);
 475
 476         lc->sync_bits = vmalloc(bitset_size);
 477         if (!lc->sync_bits) {
 478                 DMWARN("couldn't allocate sync bitset");
 479                 if (!dev)
 480                         vfree(lc->clean_bits);
 481                 else
 482                         dm_io_client_destroy(lc->io_req.client);
 483                 vfree(lc->disk_header);
 484                 kfree(lc);
 485                 return -ENOMEM;
 486         }
 487         memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
 488         lc->sync_count = (sync == NOSYNC) ? region_count : 0;
 489
 490         lc->recovering_bits = vmalloc(bitset_size);
 491         if (!lc->recovering_bits) {
 492                 DMWARN("couldn't allocate sync bitset");
 493                 vfree(lc->sync_bits);
 494                 if (!dev)
 495                         vfree(lc->clean_bits);
 496                 else
 497                         dm_io_client_destroy(lc->io_req.client);
 498                 vfree(lc->disk_header);
 499                 kfree(lc);
 500                 return -ENOMEM;
 501         }
 502         memset(lc->recovering_bits, 0, bitset_size);
 503         lc->sync_search = 0;
 504         log->context = lc;
 505
 506         return 0;
 507 }
 508
 509 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 510                     unsigned int argc, char **argv)
 511 {
 512         return create_log_context(log, ti, argc, argv, NULL);
 513 }
 514
 515 static void destroy_log_context(struct log_c *lc)
 516 {
 517         vfree(lc->sync_bits);
 518         vfree(lc->recovering_bits);
 519         kfree(lc);
 520 }
 521
 522 static void core_dtr(struct dm_dirty_log *log)
 523 {
 524         struct log_c *lc = (struct log_c *) log->context;
 525
 526         vfree(lc->clean_bits);
 527         destroy_log_context(lc);
 528 }
 529
 530 /*----------------------------------------------------------------
 531  * disk log constructor/destructor
 532  *
 533  * argv contains log_device region_size followed optionally by [no]sync
 534  *--------------------------------------------------------------*/
 535 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 536                     unsigned int argc, char **argv)
 537 {
 538         int r;
 539         struct dm_dev *dev;
 540
 541         if (argc < 2 || argc > 3) {
 542                 DMWARN("wrong number of arguments to disk dirty region log");
 543                 return -EINVAL;
 544         }
 545
 546         r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
 547                           FMODE_READ | FMODE_WRITE, &dev);
 548         if (r)
 549                 return r;
 550
 551         r = create_log_context(log, ti, argc - 1, argv + 1, dev);
 552         if (r) {
 553                 dm_put_device(ti, dev);
 554                 return r;
 555         }
 556
 557         return 0;
 558 }
 559
 560 static void disk_dtr(struct dm_dirty_log *log)
 561 {
 562         struct log_c *lc = (struct log_c *) log->context;
 563
 564         dm_put_device(lc->ti, lc->log_dev);
 565         vfree(lc->disk_header);
 566         dm_io_client_destroy(lc->io_req.client);
 567         destroy_log_context(lc);
 568 }
 569
 570 static int count_bits32(uint32_t *addr, unsigned size)
 571 {
 572         int count = 0, i;
 573
 574         for (i = 0; i < size; i++) {
 575                 count += hweight32(*(addr+i));
 576         }
 577         return count;
 578 }
 579
 580 static void fail_log_device(struct log_c *lc)
 581 {
 582         if (lc->log_dev_failed)
 583                 return;
 584
 585         lc->log_dev_failed = 1;
 586         dm_table_event(lc->ti->table);
 587 }
 588
 589 static int disk_resume(struct dm_dirty_log *log)
 590 {
 591         int r;
 592         unsigned i;
 593         struct log_c *lc = (struct log_c *) log->context;
 594         size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
 595
 596         /* read the disk header */
 597         r = read_header(lc);
 598         if (r) {
 599                 DMWARN("%s: Failed to read header on dirty region log device",
 600                        lc->log_dev->name);
 601                 fail_log_device(lc);
 602                 /*
 603                  * If the log device cannot be read, we must assume
 604                  * all regions are out-of-sync.  If we simply return
 605                  * here, the state will be uninitialized and could
 606                  * lead us to return 'in-sync' status for regions
 607                  * that are actually 'out-of-sync'.
 608                  */
 609                 lc->header.nr_regions = 0;
 610         }
 611
 612         /* set or clear any new bits -- device has grown */
 613         if (lc->sync == NOSYNC)
 614                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
 615                         /* FIXME: amazingly inefficient */
 616                         log_set_bit(lc, lc->clean_bits, i);
 617         else
 618                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
 619                         /* FIXME: amazingly inefficient */
 620                         log_clear_bit(lc, lc->clean_bits, i);
 621
 622         /* clear any old bits -- device has shrunk */
 623         for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
 624                 log_clear_bit(lc, lc->clean_bits, i);
 625
 626         /* copy clean across to sync */
 627         memcpy(lc->sync_bits, lc->clean_bits, size);
 628         lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
 629         lc->sync_search = 0;
 630
 631         /* set the correct number of regions in the header */
 632         lc->header.nr_regions = lc->region_count;
 633
 634         header_to_disk(&lc->header, lc->disk_header);
 635
 636         /* write the new header */
 637         r = rw_header(lc, WRITE);
 638         if (!r) {
 639                 r = flush_header(lc);
 640                 if (r)
 641                         lc->log_dev_flush_failed = 1;
 642         }
 643         if (r) {
 644                 DMWARN("%s: Failed to write header on dirty region log device",
 645                        lc->log_dev->name);
 646                 fail_log_device(lc);
 647         }
 648
 649         return r;
 650 }
 651
 652 static uint32_t core_get_region_size(struct dm_dirty_log *log)
 653 {
 654         struct log_c *lc = (struct log_c *) log->context;
 655         return lc->region_size;
 656 }
 657
 658 static int core_resume(struct dm_dirty_log *log)
 659 {
 660         struct log_c *lc = (struct log_c *) log->context;
 661         lc->sync_search = 0;
 662         return 0;
 663 }
 664
 665 static int core_is_clean(struct dm_dirty_log *log, region_t region)
 666 {
 667         struct log_c *lc = (struct log_c *) log->context;
 668         return log_test_bit(lc->clean_bits, region);
 669 }
 670
 671 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
 672 {
 673         struct log_c *lc = (struct log_c *) log->context;
 674         return log_test_bit(lc->sync_bits, region);
 675 }
 676
 677 static int core_flush(struct dm_dirty_log *log)
 678 {
 679         /* no op */
 680         return 0;
 681 }
 682
 683 static int disk_flush(struct dm_dirty_log *log)
 684 {
 685         int r, i;
 686         struct log_c *lc = log->context;
 687
 688         /* only write if the log has changed */
 689         if (!lc->touched_cleaned && !lc->touched_dirtied)
 690                 return 0;
 691
 692         if (lc->touched_cleaned && log->flush_callback_fn &&
 693             log->flush_callback_fn(lc->ti)) {
 694                 /*
 695                  * At this point it is impossible to determine which
 696                  * regions are clean and which are dirty (without
 697                  * re-reading the log off disk). So mark all of them
 698                  * dirty.
 699                  */
 700                 lc->flush_failed = 1;
 701                 for (i = 0; i < lc->region_count; i++)
 702                         log_clear_bit(lc, lc->clean_bits, i);
 703         }
 704
 705         r = rw_header(lc, WRITE);
 706         if (r)
 707                 fail_log_device(lc);
 708         else {
 709                 if (lc->touched_dirtied) {
 710                         r = flush_header(lc);
 711                         if (r) {
 712                                 lc->log_dev_flush_failed = 1;
 713                                 fail_log_device(lc);
 714                         } else
 715                                 lc->touched_dirtied = 0;
 716                 }
 717                 lc->touched_cleaned = 0;
 718         }
 719
 720         return r;
 721 }
 722
 723 static void core_mark_region(struct dm_dirty_log *log, region_t region)
 724 {
 725         struct log_c *lc = (struct log_c *) log->context;
 726         log_clear_bit(lc, lc->clean_bits, region);
 727 }
 728
 729 static void core_clear_region(struct dm_dirty_log *log, region_t region)
 730 {
 731         struct log_c *lc = (struct log_c *) log->context;
 732         if (likely(!lc->flush_failed))
 733                 log_set_bit(lc, lc->clean_bits, region);
 734 }
 735
 736 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
 737 {
 738         struct log_c *lc = (struct log_c *) log->context;
 739
 740         if (lc->sync_search >= lc->region_count)
 741                 return 0;
 742
 743         do {
 744                 *region = ext2_find_next_zero_bit(
 745                                              (unsigned long *) lc->sync_bits,
 746                                              lc->region_count,
 747                                              lc->sync_search);
 748                 lc->sync_search = *region + 1;
 749
 750                 if (*region >= lc->region_count)
 751                         return 0;
 752
 753         } while (log_test_bit(lc->recovering_bits, *region));
 754
 755         log_set_bit(lc, lc->recovering_bits, *region);
 756         return 1;
 757 }
 758
 759 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
 760                                  int in_sync)
 761 {
 762         struct log_c *lc = (struct log_c *) log->context;
 763
 764         log_clear_bit(lc, lc->recovering_bits, region);
 765         if (in_sync) {
 766                 log_set_bit(lc, lc->sync_bits, region);
 767                 lc->sync_count++;
 768         } else if (log_test_bit(lc->sync_bits, region)) {
 769                 lc->sync_count--;
 770                 log_clear_bit(lc, lc->sync_bits, region);
 771         }
 772 }
 773
 774 static region_t core_get_sync_count(struct dm_dirty_log *log)
 775 {
 776         struct log_c *lc = (struct log_c *) log->context;
 777
 778         return lc->sync_count;
 779 }
 780
 781 #define DMEMIT_SYNC \
 782         if (lc->sync != DEFAULTSYNC) \
 783                 DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
 784
 785 static int core_status(struct dm_dirty_log *log, status_type_t status,
 786                        char *result, unsigned int maxlen)
 787 {
 788         int sz = 0;
 789         struct log_c *lc = log->context;
 790
 791         switch(status) {
 792         case STATUSTYPE_INFO:
 793                 DMEMIT("1 %s", log->type->name);
 794                 break;
 795
 796         case STATUSTYPE_TABLE:
 797                 DMEMIT("%s %u %u ", log->type->name,
 798                        lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
 799                 DMEMIT_SYNC;
 800         }
 801
 802         return sz;
 803 }
 804
 805 static int disk_status(struct dm_dirty_log *log, status_type_t status,
 806                        char *result, unsigned int maxlen)
 807 {
 808         int sz = 0;
 809         struct log_c *lc = log->context;
 810
 811         switch(status) {
 812         case STATUSTYPE_INFO:
 813                 DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
 814                        lc->log_dev_flush_failed ? 'F' :
 815                        lc->log_dev_failed ? 'D' :
 816                        'A');
 817                 break;
 818
 819         case STATUSTYPE_TABLE:
 820                 DMEMIT("%s %u %s %u ", log->type->name,
 821                        lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
 822                        lc->region_size);
 823                 DMEMIT_SYNC;
 824         }
 825
 826         return sz;
 827 }
 828
 829 static struct dm_dirty_log_type _core_type = {
 830         .name = "core",
 831         .module = THIS_MODULE,
 832         .ctr = core_ctr,
 833         .dtr = core_dtr,
 834         .resume = core_resume,
 835         .get_region_size = core_get_region_size,
 836         .is_clean = core_is_clean,
 837         .in_sync = core_in_sync,
 838         .flush = core_flush,
 839         .mark_region = core_mark_region,
 840         .clear_region = core_clear_region,
 841         .get_resync_work = core_get_resync_work,
 842         .set_region_sync = core_set_region_sync,
 843         .get_sync_count = core_get_sync_count,
 844         .status = core_status,
 845 };
 846
 847 static struct dm_dirty_log_type _disk_type = {
 848         .name = "disk",
 849         .module = THIS_MODULE,
 850         .ctr = disk_ctr,
 851         .dtr = disk_dtr,
 852         .postsuspend = disk_flush,
 853         .resume = disk_resume,
 854         .get_region_size = core_get_region_size,
 855         .is_clean = core_is_clean,
 856         .in_sync = core_in_sync,
 857         .flush = disk_flush,
 858         .mark_region = core_mark_region,
 859         .clear_region = core_clear_region,
 860         .get_resync_work = core_get_resync_work,
 861         .set_region_sync = core_set_region_sync,
 862         .get_sync_count = core_get_sync_count,
 863         .status = disk_status,
 864 };
 865
 866 static int __init dm_dirty_log_init(void)
 867 {
 868         int r;
 869
 870         r = dm_dirty_log_type_register(&_core_type);
 871         if (r)
 872                 DMWARN("couldn't register core log");
 873
 874         r = dm_dirty_log_type_register(&_disk_type);
 875         if (r) {
 876                 DMWARN("couldn't register disk type");
 877                 dm_dirty_log_type_unregister(&_core_type);
 878         }
 879
 880         return r;
 881 }
 882
 883 static void __exit dm_dirty_log_exit(void)
 884 {
 885         dm_dirty_log_type_unregister(&_disk_type);
 886         dm_dirty_log_type_unregister(&_core_type);
 887 }
 888
 889 module_init(dm_dirty_log_init);
 890 module_exit(dm_dirty_log_exit);
 891
 892 MODULE_DESCRIPTION(DM_NAME " dirty region log");
 893 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
 894 MODULE_LICENSE("GPL");