drivers/md/dm-raid1.c

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This source file includes following definitions.
wakeup_mirrord
delayed_wake_fn
delayed_wake
wakeup_all_recovery_waiters
queue_bio
dispatch_bios
bio_get_m
bio_set_m
get_default_mirror
set_default_mirror
get_valid_mirror
fail_mirror
mirror_flush
recovery_complete
recover
reset_ms_flags
do_recovery
choose_mirror
default_ok
mirror_available
map_sector
map_bio
map_region
hold_bio
read_callback
read_async_bio
region_in_sync
do_reads
write_callback
do_write
do_writes
do_failures
trigger_event
do_mirror
alloc_context
free_context
get_mirror
create_dirty_log
parse_features
mirror_ctr
mirror_dtr
mirror_map
mirror_end_io
mirror_presuspend
mirror_postsuspend
mirror_resume
device_status_char
mirror_status
mirror_iterate_devices
dm_mirror_init
dm_mirror_exit
   1 /*
   2  * Copyright (C) 2003 Sistina Software Limited.
   3  * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7 
   8 #include "dm-bio-record.h"
   9 
  10 #include <linux/init.h>
  11 #include <linux/mempool.h>
  12 #include <linux/module.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/slab.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/device-mapper.h>
  17 #include <linux/dm-io.h>
  18 #include <linux/dm-dirty-log.h>
  19 #include <linux/dm-kcopyd.h>
  20 #include <linux/dm-region-hash.h>
  21 
  22 #define DM_MSG_PREFIX "raid1"
  23 
  24 #define MAX_RECOVERY 1  /* Maximum number of regions recovered in parallel. */
  25 
  26 #define MAX_NR_MIRRORS  (DM_KCOPYD_MAX_REGIONS + 1)
  27 
  28 #define DM_RAID1_HANDLE_ERRORS  0x01
  29 #define DM_RAID1_KEEP_LOG       0x02
  30 #define errors_handled(p)       ((p)->features & DM_RAID1_HANDLE_ERRORS)
  31 #define keep_log(p)             ((p)->features & DM_RAID1_KEEP_LOG)
  32 
  33 static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
  34 
  35 /*-----------------------------------------------------------------
  36  * Mirror set structures.
  37  *---------------------------------------------------------------*/
  38 enum dm_raid1_error {
  39         DM_RAID1_WRITE_ERROR,
  40         DM_RAID1_FLUSH_ERROR,
  41         DM_RAID1_SYNC_ERROR,
  42         DM_RAID1_READ_ERROR
  43 };
  44 
  45 struct mirror {
  46         struct mirror_set *ms;
  47         atomic_t error_count;
  48         unsigned long error_type;
  49         struct dm_dev *dev;
  50         sector_t offset;
  51 };
  52 
  53 struct mirror_set {
  54         struct dm_target *ti;
  55         struct list_head list;
  56 
  57         uint64_t features;
  58 
  59         spinlock_t lock;        /* protects the lists */
  60         struct bio_list reads;
  61         struct bio_list writes;
  62         struct bio_list failures;
  63         struct bio_list holds;  /* bios are waiting until suspend */
  64 
  65         struct dm_region_hash *rh;
  66         struct dm_kcopyd_client *kcopyd_client;
  67         struct dm_io_client *io_client;
  68 
  69         /* recovery */
  70         region_t nr_regions;
  71         int in_sync;
  72         int log_failure;
  73         int leg_failure;
  74         atomic_t suspend;
  75 
  76         atomic_t default_mirror;        /* Default mirror */
  77 
  78         struct workqueue_struct *kmirrord_wq;
  79         struct work_struct kmirrord_work;
  80         struct timer_list timer;
  81         unsigned long timer_pending;
  82 
  83         struct work_struct trigger_event;
  84 
  85         unsigned nr_mirrors;
  86         struct mirror mirror[0];
  87 };
  88 
  89 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle,
  90                 "A percentage of time allocated for raid resynchronization");
  91 
  92 static void wakeup_mirrord(void *context)
  93 {
  94         struct mirror_set *ms = context;
  95 
  96         queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
  97 }
  98 
  99 static void delayed_wake_fn(struct timer_list *t)
 100 {
 101         struct mirror_set *ms = from_timer(ms, t, timer);
 102 
 103         clear_bit(0, &ms->timer_pending);
 104         wakeup_mirrord(ms);
 105 }
 106 
 107 static void delayed_wake(struct mirror_set *ms)
 108 {
 109         if (test_and_set_bit(0, &ms->timer_pending))
 110                 return;
 111 
 112         ms->timer.expires = jiffies + HZ / 5;
 113         add_timer(&ms->timer);
 114 }
 115 
 116 static void wakeup_all_recovery_waiters(void *context)
 117 {
 118         wake_up_all(&_kmirrord_recovery_stopped);
 119 }
 120 
 121 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
 122 {
 123         unsigned long flags;
 124         int should_wake = 0;
 125         struct bio_list *bl;
 126 
 127         bl = (rw == WRITE) ? &ms->writes : &ms->reads;
 128         spin_lock_irqsave(&ms->lock, flags);
 129         should_wake = !(bl->head);
 130         bio_list_add(bl, bio);
 131         spin_unlock_irqrestore(&ms->lock, flags);
 132 
 133         if (should_wake)
 134                 wakeup_mirrord(ms);
 135 }
 136 
 137 static void dispatch_bios(void *context, struct bio_list *bio_list)
 138 {
 139         struct mirror_set *ms = context;
 140         struct bio *bio;
 141 
 142         while ((bio = bio_list_pop(bio_list)))
 143                 queue_bio(ms, bio, WRITE);
 144 }
 145 
 146 struct dm_raid1_bio_record {
 147         struct mirror *m;
 148         /* if details->bi_disk == NULL, details were not saved */
 149         struct dm_bio_details details;
 150         region_t write_region;
 151 };
 152 
 153 /*
 154  * Every mirror should look like this one.
 155  */
 156 #define DEFAULT_MIRROR 0
 157 
 158 /*
 159  * This is yucky.  We squirrel the mirror struct away inside
 160  * bi_next for read/write buffers.  This is safe since the bh
 161  * doesn't get submitted to the lower levels of block layer.
 162  */
 163 static struct mirror *bio_get_m(struct bio *bio)
 164 {
 165         return (struct mirror *) bio->bi_next;
 166 }
 167 
 168 static void bio_set_m(struct bio *bio, struct mirror *m)
 169 {
 170         bio->bi_next = (struct bio *) m;
 171 }
 172 
 173 static struct mirror *get_default_mirror(struct mirror_set *ms)
 174 {
 175         return &ms->mirror[atomic_read(&ms->default_mirror)];
 176 }
 177 
 178 static void set_default_mirror(struct mirror *m)
 179 {
 180         struct mirror_set *ms = m->ms;
 181         struct mirror *m0 = &(ms->mirror[0]);
 182 
 183         atomic_set(&ms->default_mirror, m - m0);
 184 }
 185 
 186 static struct mirror *get_valid_mirror(struct mirror_set *ms)
 187 {
 188         struct mirror *m;
 189 
 190         for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
 191                 if (!atomic_read(&m->error_count))
 192                         return m;
 193 
 194         return NULL;
 195 }
 196 
 197 /* fail_mirror
 198  * @m: mirror device to fail
 199  * @error_type: one of the enum's, DM_RAID1_*_ERROR
 200  *
 201  * If errors are being handled, record the type of
 202  * error encountered for this device.  If this type
 203  * of error has already been recorded, we can return;
 204  * otherwise, we must signal userspace by triggering
 205  * an event.  Additionally, if the device is the
 206  * primary device, we must choose a new primary, but
 207  * only if the mirror is in-sync.
 208  *
 209  * This function must not block.
 210  */
 211 static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
 212 {
 213         struct mirror_set *ms = m->ms;
 214         struct mirror *new;
 215 
 216         ms->leg_failure = 1;
 217 
 218         /*
 219          * error_count is used for nothing more than a
 220          * simple way to tell if a device has encountered
 221          * errors.
 222          */
 223         atomic_inc(&m->error_count);
 224 
 225         if (test_and_set_bit(error_type, &m->error_type))
 226                 return;
 227 
 228         if (!errors_handled(ms))
 229                 return;
 230 
 231         if (m != get_default_mirror(ms))
 232                 goto out;
 233 
 234         if (!ms->in_sync && !keep_log(ms)) {
 235                 /*
 236                  * Better to issue requests to same failing device
 237                  * than to risk returning corrupt data.
 238                  */
 239                 DMERR("Primary mirror (%s) failed while out-of-sync: "
 240                       "Reads may fail.", m->dev->name);
 241                 goto out;
 242         }
 243 
 244         new = get_valid_mirror(ms);
 245         if (new)
 246                 set_default_mirror(new);
 247         else
 248                 DMWARN("All sides of mirror have failed.");
 249 
 250 out:
 251         schedule_work(&ms->trigger_event);
 252 }
 253 
 254 static int mirror_flush(struct dm_target *ti)
 255 {
 256         struct mirror_set *ms = ti->private;
 257         unsigned long error_bits;
 258 
 259         unsigned int i;
 260         struct dm_io_region io[MAX_NR_MIRRORS];
 261         struct mirror *m;
 262         struct dm_io_request io_req = {
 263                 .bi_op = REQ_OP_WRITE,
 264                 .bi_op_flags = REQ_PREFLUSH | REQ_SYNC,
 265                 .mem.type = DM_IO_KMEM,
 266                 .mem.ptr.addr = NULL,
 267                 .client = ms->io_client,
 268         };
 269 
 270         for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
 271                 io[i].bdev = m->dev->bdev;
 272                 io[i].sector = 0;
 273                 io[i].count = 0;
 274         }
 275 
 276         error_bits = -1;
 277         dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
 278         if (unlikely(error_bits != 0)) {
 279                 for (i = 0; i < ms->nr_mirrors; i++)
 280                         if (test_bit(i, &error_bits))
 281                                 fail_mirror(ms->mirror + i,
 282                                             DM_RAID1_FLUSH_ERROR);
 283                 return -EIO;
 284         }
 285 
 286         return 0;
 287 }
 288 
 289 /*-----------------------------------------------------------------
 290  * Recovery.
 291  *
 292  * When a mirror is first activated we may find that some regions
 293  * are in the no-sync state.  We have to recover these by
 294  * recopying from the default mirror to all the others.
 295  *---------------------------------------------------------------*/
 296 static void recovery_complete(int read_err, unsigned long write_err,
 297                               void *context)
 298 {
 299         struct dm_region *reg = context;
 300         struct mirror_set *ms = dm_rh_region_context(reg);
 301         int m, bit = 0;
 302 
 303         if (read_err) {
 304                 /* Read error means the failure of default mirror. */
 305                 DMERR_LIMIT("Unable to read primary mirror during recovery");
 306                 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
 307         }
 308 
 309         if (write_err) {
 310                 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
 311                             write_err);
 312                 /*
 313                  * Bits correspond to devices (excluding default mirror).
 314                  * The default mirror cannot change during recovery.
 315                  */
 316                 for (m = 0; m < ms->nr_mirrors; m++) {
 317                         if (&ms->mirror[m] == get_default_mirror(ms))
 318                                 continue;
 319                         if (test_bit(bit, &write_err))
 320                                 fail_mirror(ms->mirror + m,
 321                                             DM_RAID1_SYNC_ERROR);
 322                         bit++;
 323                 }
 324         }
 325 
 326         dm_rh_recovery_end(reg, !(read_err || write_err));
 327 }
 328 
 329 static void recover(struct mirror_set *ms, struct dm_region *reg)
 330 {
 331         unsigned i;
 332         struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
 333         struct mirror *m;
 334         unsigned long flags = 0;
 335         region_t key = dm_rh_get_region_key(reg);
 336         sector_t region_size = dm_rh_get_region_size(ms->rh);
 337 
 338         /* fill in the source */
 339         m = get_default_mirror(ms);
 340         from.bdev = m->dev->bdev;
 341         from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
 342         if (key == (ms->nr_regions - 1)) {
 343                 /*
 344                  * The final region may be smaller than
 345                  * region_size.
 346                  */
 347                 from.count = ms->ti->len & (region_size - 1);
 348                 if (!from.count)
 349                         from.count = region_size;
 350         } else
 351                 from.count = region_size;
 352 
 353         /* fill in the destinations */
 354         for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
 355                 if (&ms->mirror[i] == get_default_mirror(ms))
 356                         continue;
 357 
 358                 m = ms->mirror + i;
 359                 dest->bdev = m->dev->bdev;
 360                 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
 361                 dest->count = from.count;
 362                 dest++;
 363         }
 364 
 365         /* hand to kcopyd */
 366         if (!errors_handled(ms))
 367                 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags);
 368 
 369         dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
 370                        flags, recovery_complete, reg);
 371 }
 372 
 373 static void reset_ms_flags(struct mirror_set *ms)
 374 {
 375         unsigned int m;
 376 
 377         ms->leg_failure = 0;
 378         for (m = 0; m < ms->nr_mirrors; m++) {
 379                 atomic_set(&(ms->mirror[m].error_count), 0);
 380                 ms->mirror[m].error_type = 0;
 381         }
 382 }
 383 
 384 static void do_recovery(struct mirror_set *ms)
 385 {
 386         struct dm_region *reg;
 387         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
 388 
 389         /*
 390          * Start quiescing some regions.
 391          */
 392         dm_rh_recovery_prepare(ms->rh);
 393 
 394         /*
 395          * Copy any already quiesced regions.
 396          */
 397         while ((reg = dm_rh_recovery_start(ms->rh)))
 398                 recover(ms, reg);
 399 
 400         /*
 401          * Update the in sync flag.
 402          */
 403         if (!ms->in_sync &&
 404             (log->type->get_sync_count(log) == ms->nr_regions)) {
 405                 /* the sync is complete */
 406                 dm_table_event(ms->ti->table);
 407                 ms->in_sync = 1;
 408                 reset_ms_flags(ms);
 409         }
 410 }
 411 
 412 /*-----------------------------------------------------------------
 413  * Reads
 414  *---------------------------------------------------------------*/
 415 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
 416 {
 417         struct mirror *m = get_default_mirror(ms);
 418 
 419         do {
 420                 if (likely(!atomic_read(&m->error_count)))
 421                         return m;
 422 
 423                 if (m-- == ms->mirror)
 424                         m += ms->nr_mirrors;
 425         } while (m != get_default_mirror(ms));
 426 
 427         return NULL;
 428 }
 429 
 430 static int default_ok(struct mirror *m)
 431 {
 432         struct mirror *default_mirror = get_default_mirror(m->ms);
 433 
 434         return !atomic_read(&default_mirror->error_count);
 435 }
 436 
 437 static int mirror_available(struct mirror_set *ms, struct bio *bio)
 438 {
 439         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
 440         region_t region = dm_rh_bio_to_region(ms->rh, bio);
 441 
 442         if (log->type->in_sync(log, region, 0))
 443                 return choose_mirror(ms,  bio->bi_iter.bi_sector) ? 1 : 0;
 444 
 445         return 0;
 446 }
 447 
 448 /*
 449  * remap a buffer to a particular mirror.
 450  */
 451 static sector_t map_sector(struct mirror *m, struct bio *bio)
 452 {
 453         if (unlikely(!bio->bi_iter.bi_size))
 454                 return 0;
 455         return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector);
 456 }
 457 
 458 static void map_bio(struct mirror *m, struct bio *bio)
 459 {
 460         bio_set_dev(bio, m->dev->bdev);
 461         bio->bi_iter.bi_sector = map_sector(m, bio);
 462 }
 463 
 464 static void map_region(struct dm_io_region *io, struct mirror *m,
 465                        struct bio *bio)
 466 {
 467         io->bdev = m->dev->bdev;
 468         io->sector = map_sector(m, bio);
 469         io->count = bio_sectors(bio);
 470 }
 471 
 472 static void hold_bio(struct mirror_set *ms, struct bio *bio)
 473 {
 474         /*
 475          * Lock is required to avoid race condition during suspend
 476          * process.
 477          */
 478         spin_lock_irq(&ms->lock);
 479 
 480         if (atomic_read(&ms->suspend)) {
 481                 spin_unlock_irq(&ms->lock);
 482 
 483                 /*
 484                  * If device is suspended, complete the bio.
 485                  */
 486                 if (dm_noflush_suspending(ms->ti))
 487                         bio->bi_status = BLK_STS_DM_REQUEUE;
 488                 else
 489                         bio->bi_status = BLK_STS_IOERR;
 490 
 491                 bio_endio(bio);
 492                 return;
 493         }
 494 
 495         /*
 496          * Hold bio until the suspend is complete.
 497          */
 498         bio_list_add(&ms->holds, bio);
 499         spin_unlock_irq(&ms->lock);
 500 }
 501 
 502 /*-----------------------------------------------------------------
 503  * Reads
 504  *---------------------------------------------------------------*/
 505 static void read_callback(unsigned long error, void *context)
 506 {
 507         struct bio *bio = context;
 508         struct mirror *m;
 509 
 510         m = bio_get_m(bio);
 511         bio_set_m(bio, NULL);
 512 
 513         if (likely(!error)) {
 514                 bio_endio(bio);
 515                 return;
 516         }
 517 
 518         fail_mirror(m, DM_RAID1_READ_ERROR);
 519 
 520         if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
 521                 DMWARN_LIMIT("Read failure on mirror device %s.  "
 522                              "Trying alternative device.",
 523                              m->dev->name);
 524                 queue_bio(m->ms, bio, bio_data_dir(bio));
 525                 return;
 526         }
 527 
 528         DMERR_LIMIT("Read failure on mirror device %s.  Failing I/O.",
 529                     m->dev->name);
 530         bio_io_error(bio);
 531 }
 532 
 533 /* Asynchronous read. */
 534 static void read_async_bio(struct mirror *m, struct bio *bio)
 535 {
 536         struct dm_io_region io;
 537         struct dm_io_request io_req = {
 538                 .bi_op = REQ_OP_READ,
 539                 .bi_op_flags = 0,
 540                 .mem.type = DM_IO_BIO,
 541                 .mem.ptr.bio = bio,
 542                 .notify.fn = read_callback,
 543                 .notify.context = bio,
 544                 .client = m->ms->io_client,
 545         };
 546 
 547         map_region(&io, m, bio);
 548         bio_set_m(bio, m);
 549         BUG_ON(dm_io(&io_req, 1, &io, NULL));
 550 }
 551 
 552 static inline int region_in_sync(struct mirror_set *ms, region_t region,
 553                                  int may_block)
 554 {
 555         int state = dm_rh_get_state(ms->rh, region, may_block);
 556         return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
 557 }
 558 
 559 static void do_reads(struct mirror_set *ms, struct bio_list *reads)
 560 {
 561         region_t region;
 562         struct bio *bio;
 563         struct mirror *m;
 564 
 565         while ((bio = bio_list_pop(reads))) {
 566                 region = dm_rh_bio_to_region(ms->rh, bio);
 567                 m = get_default_mirror(ms);
 568 
 569                 /*
 570                  * We can only read balance if the region is in sync.
 571                  */
 572                 if (likely(region_in_sync(ms, region, 1)))
 573                         m = choose_mirror(ms, bio->bi_iter.bi_sector);
 574                 else if (m && atomic_read(&m->error_count))
 575                         m = NULL;
 576 
 577                 if (likely(m))
 578                         read_async_bio(m, bio);
 579                 else
 580                         bio_io_error(bio);
 581         }
 582 }
 583 
 584 /*-----------------------------------------------------------------
 585  * Writes.
 586  *
 587  * We do different things with the write io depending on the
 588  * state of the region that it's in:
 589  *
 590  * SYNC:        increment pending, use kcopyd to write to *all* mirrors
 591  * RECOVERING:  delay the io until recovery completes
 592  * NOSYNC:      increment pending, just write to the default mirror
 593  *---------------------------------------------------------------*/
 594 
 595 
 596 static void write_callback(unsigned long error, void *context)
 597 {
 598         unsigned i;
 599         struct bio *bio = (struct bio *) context;
 600         struct mirror_set *ms;
 601         int should_wake = 0;
 602         unsigned long flags;
 603 
 604         ms = bio_get_m(bio)->ms;
 605         bio_set_m(bio, NULL);
 606 
 607         /*
 608          * NOTE: We don't decrement the pending count here,
 609          * instead it is done by the targets endio function.
 610          * This way we handle both writes to SYNC and NOSYNC
 611          * regions with the same code.
 612          */
 613         if (likely(!error)) {
 614                 bio_endio(bio);
 615                 return;
 616         }
 617 
 618         /*
 619          * If the bio is discard, return an error, but do not
 620          * degrade the array.
 621          */
 622         if (bio_op(bio) == REQ_OP_DISCARD) {
 623                 bio->bi_status = BLK_STS_NOTSUPP;
 624                 bio_endio(bio);
 625                 return;
 626         }
 627 
 628         for (i = 0; i < ms->nr_mirrors; i++)
 629                 if (test_bit(i, &error))
 630                         fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
 631 
 632         /*
 633          * Need to raise event.  Since raising
 634          * events can block, we need to do it in
 635          * the main thread.
 636          */
 637         spin_lock_irqsave(&ms->lock, flags);
 638         if (!ms->failures.head)
 639                 should_wake = 1;
 640         bio_list_add(&ms->failures, bio);
 641         spin_unlock_irqrestore(&ms->lock, flags);
 642         if (should_wake)
 643                 wakeup_mirrord(ms);
 644 }
 645 
 646 static void do_write(struct mirror_set *ms, struct bio *bio)
 647 {
 648         unsigned int i;
 649         struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
 650         struct mirror *m;
 651         struct dm_io_request io_req = {
 652                 .bi_op = REQ_OP_WRITE,
 653                 .bi_op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH),
 654                 .mem.type = DM_IO_BIO,
 655                 .mem.ptr.bio = bio,
 656                 .notify.fn = write_callback,
 657                 .notify.context = bio,
 658                 .client = ms->io_client,
 659         };
 660 
 661         if (bio_op(bio) == REQ_OP_DISCARD) {
 662                 io_req.bi_op = REQ_OP_DISCARD;
 663                 io_req.mem.type = DM_IO_KMEM;
 664                 io_req.mem.ptr.addr = NULL;
 665         }
 666 
 667         for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
 668                 map_region(dest++, m, bio);
 669 
 670         /*
 671          * Use default mirror because we only need it to retrieve the reference
 672          * to the mirror set in write_callback().
 673          */
 674         bio_set_m(bio, get_default_mirror(ms));
 675 
 676         BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
 677 }
 678 
 679 static void do_writes(struct mirror_set *ms, struct bio_list *writes)
 680 {
 681         int state;
 682         struct bio *bio;
 683         struct bio_list sync, nosync, recover, *this_list = NULL;
 684         struct bio_list requeue;
 685         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
 686         region_t region;
 687 
 688         if (!writes->head)
 689                 return;
 690 
 691         /*
 692          * Classify each write.
 693          */
 694         bio_list_init(&sync);
 695         bio_list_init(&nosync);
 696         bio_list_init(&recover);
 697         bio_list_init(&requeue);
 698 
 699         while ((bio = bio_list_pop(writes))) {
 700                 if ((bio->bi_opf & REQ_PREFLUSH) ||
 701                     (bio_op(bio) == REQ_OP_DISCARD)) {
 702                         bio_list_add(&sync, bio);
 703                         continue;
 704                 }
 705 
 706                 region = dm_rh_bio_to_region(ms->rh, bio);
 707 
 708                 if (log->type->is_remote_recovering &&
 709                     log->type->is_remote_recovering(log, region)) {
 710                         bio_list_add(&requeue, bio);
 711                         continue;
 712                 }
 713 
 714                 state = dm_rh_get_state(ms->rh, region, 1);
 715                 switch (state) {
 716                 case DM_RH_CLEAN:
 717                 case DM_RH_DIRTY:
 718                         this_list = &sync;
 719                         break;
 720 
 721                 case DM_RH_NOSYNC:
 722                         this_list = &nosync;
 723                         break;
 724 
 725                 case DM_RH_RECOVERING:
 726                         this_list = &recover;
 727                         break;
 728                 }
 729 
 730                 bio_list_add(this_list, bio);
 731         }
 732 
 733         /*
 734          * Add bios that are delayed due to remote recovery
 735          * back on to the write queue
 736          */
 737         if (unlikely(requeue.head)) {
 738                 spin_lock_irq(&ms->lock);
 739                 bio_list_merge(&ms->writes, &requeue);
 740                 spin_unlock_irq(&ms->lock);
 741                 delayed_wake(ms);
 742         }
 743 
 744         /*
 745          * Increment the pending counts for any regions that will
 746          * be written to (writes to recover regions are going to
 747          * be delayed).
 748          */
 749         dm_rh_inc_pending(ms->rh, &sync);
 750         dm_rh_inc_pending(ms->rh, &nosync);
 751 
 752         /*
 753          * If the flush fails on a previous call and succeeds here,
 754          * we must not reset the log_failure variable.  We need
 755          * userspace interaction to do that.
 756          */
 757         ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
 758 
 759         /*
 760          * Dispatch io.
 761          */
 762         if (unlikely(ms->log_failure) && errors_handled(ms)) {
 763                 spin_lock_irq(&ms->lock);
 764                 bio_list_merge(&ms->failures, &sync);
 765                 spin_unlock_irq(&ms->lock);
 766                 wakeup_mirrord(ms);
 767         } else
 768                 while ((bio = bio_list_pop(&sync)))
 769                         do_write(ms, bio);
 770 
 771         while ((bio = bio_list_pop(&recover)))
 772                 dm_rh_delay(ms->rh, bio);
 773 
 774         while ((bio = bio_list_pop(&nosync))) {
 775                 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) {
 776                         spin_lock_irq(&ms->lock);
 777                         bio_list_add(&ms->failures, bio);
 778                         spin_unlock_irq(&ms->lock);
 779                         wakeup_mirrord(ms);
 780                 } else {
 781                         map_bio(get_default_mirror(ms), bio);
 782                         generic_make_request(bio);
 783                 }
 784         }
 785 }
 786 
 787 static void do_failures(struct mirror_set *ms, struct bio_list *failures)
 788 {
 789         struct bio *bio;
 790 
 791         if (likely(!failures->head))
 792                 return;
 793 
 794         /*
 795          * If the log has failed, unattempted writes are being
 796          * put on the holds list.  We can't issue those writes
 797          * until a log has been marked, so we must store them.
 798          *
 799          * If a 'noflush' suspend is in progress, we can requeue
 800          * the I/O's to the core.  This give userspace a chance
 801          * to reconfigure the mirror, at which point the core
 802          * will reissue the writes.  If the 'noflush' flag is
 803          * not set, we have no choice but to return errors.
 804          *
 805          * Some writes on the failures list may have been
 806          * submitted before the log failure and represent a
 807          * failure to write to one of the devices.  It is ok
 808          * for us to treat them the same and requeue them
 809          * as well.
 810          */
 811         while ((bio = bio_list_pop(failures))) {
 812                 if (!ms->log_failure) {
 813                         ms->in_sync = 0;
 814                         dm_rh_mark_nosync(ms->rh, bio);
 815                 }
 816 
 817                 /*
 818                  * If all the legs are dead, fail the I/O.
 819                  * If the device has failed and keep_log is enabled,
 820                  * fail the I/O.
 821                  *
 822                  * If we have been told to handle errors, and keep_log
 823                  * isn't enabled, hold the bio and wait for userspace to
 824                  * deal with the problem.
 825                  *
 826                  * Otherwise pretend that the I/O succeeded. (This would
 827                  * be wrong if the failed leg returned after reboot and
 828                  * got replicated back to the good legs.)
 829                  */
 830                 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure)))
 831                         bio_io_error(bio);
 832                 else if (errors_handled(ms) && !keep_log(ms))
 833                         hold_bio(ms, bio);
 834                 else
 835                         bio_endio(bio);
 836         }
 837 }
 838 
 839 static void trigger_event(struct work_struct *work)
 840 {
 841         struct mirror_set *ms =
 842                 container_of(work, struct mirror_set, trigger_event);
 843 
 844         dm_table_event(ms->ti->table);
 845 }
 846 
 847 /*-----------------------------------------------------------------
 848  * kmirrord
 849  *---------------------------------------------------------------*/
 850 static void do_mirror(struct work_struct *work)
 851 {
 852         struct mirror_set *ms = container_of(work, struct mirror_set,
 853                                              kmirrord_work);
 854         struct bio_list reads, writes, failures;
 855         unsigned long flags;
 856 
 857         spin_lock_irqsave(&ms->lock, flags);
 858         reads = ms->reads;
 859         writes = ms->writes;
 860         failures = ms->failures;
 861         bio_list_init(&ms->reads);
 862         bio_list_init(&ms->writes);
 863         bio_list_init(&ms->failures);
 864         spin_unlock_irqrestore(&ms->lock, flags);
 865 
 866         dm_rh_update_states(ms->rh, errors_handled(ms));
 867         do_recovery(ms);
 868         do_reads(ms, &reads);
 869         do_writes(ms, &writes);
 870         do_failures(ms, &failures);
 871 }
 872 
 873 /*-----------------------------------------------------------------
 874  * Target functions
 875  *---------------------------------------------------------------*/
 876 static struct mirror_set *alloc_context(unsigned int nr_mirrors,
 877                                         uint32_t region_size,
 878                                         struct dm_target *ti,
 879                                         struct dm_dirty_log *dl)
 880 {
 881         struct mirror_set *ms =
 882                 kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL);
 883 
 884         if (!ms) {
 885                 ti->error = "Cannot allocate mirror context";
 886                 return NULL;
 887         }
 888 
 889         spin_lock_init(&ms->lock);
 890         bio_list_init(&ms->reads);
 891         bio_list_init(&ms->writes);
 892         bio_list_init(&ms->failures);
 893         bio_list_init(&ms->holds);
 894 
 895         ms->ti = ti;
 896         ms->nr_mirrors = nr_mirrors;
 897         ms->nr_regions = dm_sector_div_up(ti->len, region_size);
 898         ms->in_sync = 0;
 899         ms->log_failure = 0;
 900         ms->leg_failure = 0;
 901         atomic_set(&ms->suspend, 0);
 902         atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
 903 
 904         ms->io_client = dm_io_client_create();
 905         if (IS_ERR(ms->io_client)) {
 906                 ti->error = "Error creating dm_io client";
 907                 kfree(ms);
 908                 return NULL;
 909         }
 910 
 911         ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
 912                                        wakeup_all_recovery_waiters,
 913                                        ms->ti->begin, MAX_RECOVERY,
 914                                        dl, region_size, ms->nr_regions);
 915         if (IS_ERR(ms->rh)) {
 916                 ti->error = "Error creating dirty region hash";
 917                 dm_io_client_destroy(ms->io_client);
 918                 kfree(ms);
 919                 return NULL;
 920         }
 921 
 922         return ms;
 923 }
 924 
 925 static void free_context(struct mirror_set *ms, struct dm_target *ti,
 926                          unsigned int m)
 927 {
 928         while (m--)
 929                 dm_put_device(ti, ms->mirror[m].dev);
 930 
 931         dm_io_client_destroy(ms->io_client);
 932         dm_region_hash_destroy(ms->rh);
 933         kfree(ms);
 934 }
 935 
 936 static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
 937                       unsigned int mirror, char **argv)
 938 {
 939         unsigned long long offset;
 940         char dummy;
 941         int ret;
 942 
 943         if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 ||
 944             offset != (sector_t)offset) {
 945                 ti->error = "Invalid offset";
 946                 return -EINVAL;
 947         }
 948 
 949         ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
 950                             &ms->mirror[mirror].dev);
 951         if (ret) {
 952                 ti->error = "Device lookup failure";
 953                 return ret;
 954         }
 955 
 956         ms->mirror[mirror].ms = ms;
 957         atomic_set(&(ms->mirror[mirror].error_count), 0);
 958         ms->mirror[mirror].error_type = 0;
 959         ms->mirror[mirror].offset = offset;
 960 
 961         return 0;
 962 }
 963 
 964 /*
 965  * Create dirty log: log_type #log_params <log_params>
 966  */
 967 static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
 968                                              unsigned argc, char **argv,
 969                                              unsigned *args_used)
 970 {
 971         unsigned param_count;
 972         struct dm_dirty_log *dl;
 973         char dummy;
 974 
 975         if (argc < 2) {
 976                 ti->error = "Insufficient mirror log arguments";
 977                 return NULL;
 978         }
 979 
 980         if (sscanf(argv[1], "%u%c", &param_count, &dummy) != 1) {
 981                 ti->error = "Invalid mirror log argument count";
 982                 return NULL;
 983         }
 984 
 985         *args_used = 2 + param_count;
 986 
 987         if (argc < *args_used) {
 988                 ti->error = "Insufficient mirror log arguments";
 989                 return NULL;
 990         }
 991 
 992         dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
 993                                  argv + 2);
 994         if (!dl) {
 995                 ti->error = "Error creating mirror dirty log";
 996                 return NULL;
 997         }
 998 
 999         return dl;
1000 }
1001 
1002 static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
1003                           unsigned *args_used)
1004 {
1005         unsigned num_features;
1006         struct dm_target *ti = ms->ti;
1007         char dummy;
1008         int i;
1009 
1010         *args_used = 0;
1011 
1012         if (!argc)
1013                 return 0;
1014 
1015         if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
1016                 ti->error = "Invalid number of features";
1017                 return -EINVAL;
1018         }
1019 
1020         argc--;
1021         argv++;
1022         (*args_used)++;
1023 
1024         if (num_features > argc) {
1025                 ti->error = "Not enough arguments to support feature count";
1026                 return -EINVAL;
1027         }
1028 
1029         for (i = 0; i < num_features; i++) {
1030                 if (!strcmp("handle_errors", argv[0]))
1031                         ms->features |= DM_RAID1_HANDLE_ERRORS;
1032                 else if (!strcmp("keep_log", argv[0]))
1033                         ms->features |= DM_RAID1_KEEP_LOG;
1034                 else {
1035                         ti->error = "Unrecognised feature requested";
1036                         return -EINVAL;
1037                 }
1038 
1039                 argc--;
1040                 argv++;
1041                 (*args_used)++;
1042         }
1043         if (!errors_handled(ms) && keep_log(ms)) {
1044                 ti->error = "keep_log feature requires the handle_errors feature";
1045                 return -EINVAL;
1046         }
1047 
1048         return 0;
1049 }
1050 
1051 /*
1052  * Construct a mirror mapping:
1053  *
1054  * log_type #log_params <log_params>
1055  * #mirrors [mirror_path offset]{2,}
1056  * [#features <features>]
1057  *
1058  * log_type is "core" or "disk"
1059  * #log_params is between 1 and 3
1060  *
1061  * If present, supported features are "handle_errors" and "keep_log".
1062  */
1063 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1064 {
1065         int r;
1066         unsigned int nr_mirrors, m, args_used;
1067         struct mirror_set *ms;
1068         struct dm_dirty_log *dl;
1069         char dummy;
1070 
1071         dl = create_dirty_log(ti, argc, argv, &args_used);
1072         if (!dl)
1073                 return -EINVAL;
1074 
1075         argv += args_used;
1076         argc -= args_used;
1077 
1078         if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
1079             nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
1080                 ti->error = "Invalid number of mirrors";
1081                 dm_dirty_log_destroy(dl);
1082                 return -EINVAL;
1083         }
1084 
1085         argv++, argc--;
1086 
1087         if (argc < nr_mirrors * 2) {
1088                 ti->error = "Too few mirror arguments";
1089                 dm_dirty_log_destroy(dl);
1090                 return -EINVAL;
1091         }
1092 
1093         ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1094         if (!ms) {
1095                 dm_dirty_log_destroy(dl);
1096                 return -ENOMEM;
1097         }
1098 
1099         /* Get the mirror parameter sets */
1100         for (m = 0; m < nr_mirrors; m++) {
1101                 r = get_mirror(ms, ti, m, argv);
1102                 if (r) {
1103                         free_context(ms, ti, m);
1104                         return r;
1105                 }
1106                 argv += 2;
1107                 argc -= 2;
1108         }
1109 
1110         ti->private = ms;
1111 
1112         r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh));
1113         if (r)
1114                 goto err_free_context;
1115 
1116         ti->num_flush_bios = 1;
1117         ti->num_discard_bios = 1;
1118         ti->per_io_data_size = sizeof(struct dm_raid1_bio_record);
1119 
1120         ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
1121         if (!ms->kmirrord_wq) {
1122                 DMERR("couldn't start kmirrord");
1123                 r = -ENOMEM;
1124                 goto err_free_context;
1125         }
1126         INIT_WORK(&ms->kmirrord_work, do_mirror);
1127         timer_setup(&ms->timer, delayed_wake_fn, 0);
1128         ms->timer_pending = 0;
1129         INIT_WORK(&ms->trigger_event, trigger_event);
1130 
1131         r = parse_features(ms, argc, argv, &args_used);
1132         if (r)
1133                 goto err_destroy_wq;
1134 
1135         argv += args_used;
1136         argc -= args_used;
1137 
1138         /*
1139          * Any read-balancing addition depends on the
1140          * DM_RAID1_HANDLE_ERRORS flag being present.
1141          * This is because the decision to balance depends
1142          * on the sync state of a region.  If the above
1143          * flag is not present, we ignore errors; and
1144          * the sync state may be inaccurate.
1145          */
1146 
1147         if (argc) {
1148                 ti->error = "Too many mirror arguments";
1149                 r = -EINVAL;
1150                 goto err_destroy_wq;
1151         }
1152 
1153         ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1154         if (IS_ERR(ms->kcopyd_client)) {
1155                 r = PTR_ERR(ms->kcopyd_client);
1156                 goto err_destroy_wq;
1157         }
1158 
1159         wakeup_mirrord(ms);
1160         return 0;
1161 
1162 err_destroy_wq:
1163         destroy_workqueue(ms->kmirrord_wq);
1164 err_free_context:
1165         free_context(ms, ti, ms->nr_mirrors);
1166         return r;
1167 }
1168 
1169 static void mirror_dtr(struct dm_target *ti)
1170 {
1171         struct mirror_set *ms = (struct mirror_set *) ti->private;
1172 
1173         del_timer_sync(&ms->timer);
1174         flush_workqueue(ms->kmirrord_wq);
1175         flush_work(&ms->trigger_event);
1176         dm_kcopyd_client_destroy(ms->kcopyd_client);
1177         destroy_workqueue(ms->kmirrord_wq);
1178         free_context(ms, ti, ms->nr_mirrors);
1179 }
1180 
1181 /*
1182  * Mirror mapping function
1183  */
1184 static int mirror_map(struct dm_target *ti, struct bio *bio)
1185 {
1186         int r, rw = bio_data_dir(bio);
1187         struct mirror *m;
1188         struct mirror_set *ms = ti->private;
1189         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1190         struct dm_raid1_bio_record *bio_record =
1191           dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1192 
1193         bio_record->details.bi_disk = NULL;
1194 
1195         if (rw == WRITE) {
1196                 /* Save region for mirror_end_io() handler */
1197                 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
1198                 queue_bio(ms, bio, rw);
1199                 return DM_MAPIO_SUBMITTED;
1200         }
1201 
1202         r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
1203         if (r < 0 && r != -EWOULDBLOCK)
1204                 return DM_MAPIO_KILL;
1205 
1206         /*
1207          * If region is not in-sync queue the bio.
1208          */
1209         if (!r || (r == -EWOULDBLOCK)) {
1210                 if (bio->bi_opf & REQ_RAHEAD)
1211                         return DM_MAPIO_KILL;
1212 
1213                 queue_bio(ms, bio, rw);
1214                 return DM_MAPIO_SUBMITTED;
1215         }
1216 
1217         /*
1218          * The region is in-sync and we can perform reads directly.
1219          * Store enough information so we can retry if it fails.
1220          */
1221         m = choose_mirror(ms, bio->bi_iter.bi_sector);
1222         if (unlikely(!m))
1223                 return DM_MAPIO_KILL;
1224 
1225         dm_bio_record(&bio_record->details, bio);
1226         bio_record->m = m;
1227 
1228         map_bio(m, bio);
1229 
1230         return DM_MAPIO_REMAPPED;
1231 }
1232 
1233 static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1234                 blk_status_t *error)
1235 {
1236         int rw = bio_data_dir(bio);
1237         struct mirror_set *ms = (struct mirror_set *) ti->private;
1238         struct mirror *m = NULL;
1239         struct dm_bio_details *bd = NULL;
1240         struct dm_raid1_bio_record *bio_record =
1241           dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1242 
1243         /*
1244          * We need to dec pending if this was a write.
1245          */
1246         if (rw == WRITE) {
1247                 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1248                     bio_op(bio) != REQ_OP_DISCARD)
1249                         dm_rh_dec(ms->rh, bio_record->write_region);
1250                 return DM_ENDIO_DONE;
1251         }
1252 
1253         if (*error == BLK_STS_NOTSUPP)
1254                 goto out;
1255 
1256         if (bio->bi_opf & REQ_RAHEAD)
1257                 goto out;
1258 
1259         if (unlikely(*error)) {
1260                 if (!bio_record->details.bi_disk) {
1261                         /*
1262                          * There wasn't enough memory to record necessary
1263                          * information for a retry or there was no other
1264                          * mirror in-sync.
1265                          */
1266                         DMERR_LIMIT("Mirror read failed.");
1267                         return DM_ENDIO_DONE;
1268                 }
1269 
1270                 m = bio_record->m;
1271 
1272                 DMERR("Mirror read failed from %s. Trying alternative device.",
1273                       m->dev->name);
1274 
1275                 fail_mirror(m, DM_RAID1_READ_ERROR);
1276 
1277                 /*
1278                  * A failed read is requeued for another attempt using an intact
1279                  * mirror.
1280                  */
1281                 if (default_ok(m) || mirror_available(ms, bio)) {
1282                         bd = &bio_record->details;
1283 
1284                         dm_bio_restore(bd, bio);
1285                         bio_record->details.bi_disk = NULL;
1286                         bio->bi_status = 0;
1287 
1288                         queue_bio(ms, bio, rw);
1289                         return DM_ENDIO_INCOMPLETE;
1290                 }
1291                 DMERR("All replicated volumes dead, failing I/O");
1292         }
1293 
1294 out:
1295         bio_record->details.bi_disk = NULL;
1296 
1297         return DM_ENDIO_DONE;
1298 }
1299 
1300 static void mirror_presuspend(struct dm_target *ti)
1301 {
1302         struct mirror_set *ms = (struct mirror_set *) ti->private;
1303         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1304 
1305         struct bio_list holds;
1306         struct bio *bio;
1307 
1308         atomic_set(&ms->suspend, 1);
1309 
1310         /*
1311          * Process bios in the hold list to start recovery waiting
1312          * for bios in the hold list. After the process, no bio has
1313          * a chance to be added in the hold list because ms->suspend
1314          * is set.
1315          */
1316         spin_lock_irq(&ms->lock);
1317         holds = ms->holds;
1318         bio_list_init(&ms->holds);
1319         spin_unlock_irq(&ms->lock);
1320 
1321         while ((bio = bio_list_pop(&holds)))
1322                 hold_bio(ms, bio);
1323 
1324         /*
1325          * We must finish up all the work that we've
1326          * generated (i.e. recovery work).
1327          */
1328         dm_rh_stop_recovery(ms->rh);
1329 
1330         wait_event(_kmirrord_recovery_stopped,
1331                    !dm_rh_recovery_in_flight(ms->rh));
1332 
1333         if (log->type->presuspend && log->type->presuspend(log))
1334                 /* FIXME: need better error handling */
1335                 DMWARN("log presuspend failed");
1336 
1337         /*
1338          * Now that recovery is complete/stopped and the
1339          * delayed bios are queued, we need to wait for
1340          * the worker thread to complete.  This way,
1341          * we know that all of our I/O has been pushed.
1342          */
1343         flush_workqueue(ms->kmirrord_wq);
1344 }
1345 
1346 static void mirror_postsuspend(struct dm_target *ti)
1347 {
1348         struct mirror_set *ms = ti->private;
1349         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1350 
1351         if (log->type->postsuspend && log->type->postsuspend(log))
1352                 /* FIXME: need better error handling */
1353                 DMWARN("log postsuspend failed");
1354 }
1355 
1356 static void mirror_resume(struct dm_target *ti)
1357 {
1358         struct mirror_set *ms = ti->private;
1359         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1360 
1361         atomic_set(&ms->suspend, 0);
1362         if (log->type->resume && log->type->resume(log))
1363                 /* FIXME: need better error handling */
1364                 DMWARN("log resume failed");
1365         dm_rh_start_recovery(ms->rh);
1366 }
1367 
1368 /*
1369  * device_status_char
1370  * @m: mirror device/leg we want the status of
1371  *
1372  * We return one character representing the most severe error
1373  * we have encountered.
1374  *    A => Alive - No failures
1375  *    D => Dead - A write failure occurred leaving mirror out-of-sync
1376  *    S => Sync - A sychronization failure occurred, mirror out-of-sync
1377  *    R => Read - A read failure occurred, mirror data unaffected
1378  *
1379  * Returns: <char>
1380  */
1381 static char device_status_char(struct mirror *m)
1382 {
1383         if (!atomic_read(&(m->error_count)))
1384                 return 'A';
1385 
1386         return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1387                 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1388                 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1389                 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1390 }
1391 
1392 
1393 static void mirror_status(struct dm_target *ti, status_type_t type,
1394                           unsigned status_flags, char *result, unsigned maxlen)
1395 {
1396         unsigned int m, sz = 0;
1397         int num_feature_args = 0;
1398         struct mirror_set *ms = (struct mirror_set *) ti->private;
1399         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1400         char buffer[MAX_NR_MIRRORS + 1];
1401 
1402         switch (type) {
1403         case STATUSTYPE_INFO:
1404                 DMEMIT("%d ", ms->nr_mirrors);
1405                 for (m = 0; m < ms->nr_mirrors; m++) {
1406                         DMEMIT("%s ", ms->mirror[m].dev->name);
1407                         buffer[m] = device_status_char(&(ms->mirror[m]));
1408                 }
1409                 buffer[m] = '\0';
1410 
1411                 DMEMIT("%llu/%llu 1 %s ",
1412                       (unsigned long long)log->type->get_sync_count(log),
1413                       (unsigned long long)ms->nr_regions, buffer);
1414 
1415                 sz += log->type->status(log, type, result+sz, maxlen-sz);
1416 
1417                 break;
1418 
1419         case STATUSTYPE_TABLE:
1420                 sz = log->type->status(log, type, result, maxlen);
1421 
1422                 DMEMIT("%d", ms->nr_mirrors);
1423                 for (m = 0; m < ms->nr_mirrors; m++)
1424                         DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1425                                (unsigned long long)ms->mirror[m].offset);
1426 
1427                 num_feature_args += !!errors_handled(ms);
1428                 num_feature_args += !!keep_log(ms);
1429                 if (num_feature_args) {
1430                         DMEMIT(" %d", num_feature_args);
1431                         if (errors_handled(ms))
1432                                 DMEMIT(" handle_errors");
1433                         if (keep_log(ms))
1434                                 DMEMIT(" keep_log");
1435                 }
1436 
1437                 break;
1438         }
1439 }
1440 
1441 static int mirror_iterate_devices(struct dm_target *ti,
1442                                   iterate_devices_callout_fn fn, void *data)
1443 {
1444         struct mirror_set *ms = ti->private;
1445         int ret = 0;
1446         unsigned i;
1447 
1448         for (i = 0; !ret && i < ms->nr_mirrors; i++)
1449                 ret = fn(ti, ms->mirror[i].dev,
1450                          ms->mirror[i].offset, ti->len, data);
1451 
1452         return ret;
1453 }
1454 
1455 static struct target_type mirror_target = {
1456         .name    = "mirror",
1457         .version = {1, 14, 0},
1458         .module  = THIS_MODULE,
1459         .ctr     = mirror_ctr,
1460         .dtr     = mirror_dtr,
1461         .map     = mirror_map,
1462         .end_io  = mirror_end_io,
1463         .presuspend = mirror_presuspend,
1464         .postsuspend = mirror_postsuspend,
1465         .resume  = mirror_resume,
1466         .status  = mirror_status,
1467         .iterate_devices = mirror_iterate_devices,
1468 };
1469 
1470 static int __init dm_mirror_init(void)
1471 {
1472         int r;
1473 
1474         r = dm_register_target(&mirror_target);
1475         if (r < 0) {
1476                 DMERR("Failed to register mirror target");
1477                 goto bad_target;
1478         }
1479 
1480         return 0;
1481 
1482 bad_target:
1483         return r;
1484 }
1485 
1486 static void __exit dm_mirror_exit(void)
1487 {
1488         dm_unregister_target(&mirror_target);
1489 }
1490 
1491 /* Module hooks */
1492 module_init(dm_mirror_init);
1493 module_exit(dm_mirror_exit);
1494 
1495 MODULE_DESCRIPTION(DM_NAME " mirror target");
1496 MODULE_AUTHOR("Joe Thornber");
1497 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/md/dm-raid1.c

DEFINITIONS
