drivers/md/bcache/super.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * bcache setup/teardown code, and some metadata io - read a superblock and
   4  * figure out what to do with it.
   5  *
   6  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   7  * Copyright 2012 Google, Inc.
   8  */
   9
  10 #include "bcache.h"
  11 #include "btree.h"
  12 #include "debug.h"
  13 #include "extents.h"
  14 #include "request.h"
  15 #include "writeback.h"
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/buffer_head.h>
  19 #include <linux/debugfs.h>
  20 #include <linux/genhd.h>
  21 #include <linux/idr.h>
  22 #include <linux/kthread.h>
  23 #include <linux/module.h>
  24 #include <linux/random.h>
  25 #include <linux/reboot.h>
  26 #include <linux/sysfs.h>
  27
  28 MODULE_LICENSE("GPL");
  29 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
  30
  31 static const char bcache_magic[] = {
  32         0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
  33         0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
  34 };
  35
  36 static const char invalid_uuid[] = {
  37         0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
  38         0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
  39 };
  40
  41 static struct kobject *bcache_kobj;
  42 struct mutex bch_register_lock;
  43 LIST_HEAD(bch_cache_sets);
  44 static LIST_HEAD(uncached_devices);
  45
  46 static int bcache_major;
  47 static DEFINE_IDA(bcache_device_idx);
  48 static wait_queue_head_t unregister_wait;
  49 struct workqueue_struct *bcache_wq;
  50 struct workqueue_struct *bch_journal_wq;
  51
  52 #define BTREE_MAX_PAGES         (256 * 1024 / PAGE_SIZE)
  53 /* limitation of partitions number on single bcache device */
  54 #define BCACHE_MINORS           128
  55 /* limitation of bcache devices number on single system */
  56 #define BCACHE_DEVICE_IDX_MAX   ((1U << MINORBITS)/BCACHE_MINORS)
  57
  58 /* Superblock */
  59
  60 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
  61                               struct page **res)
  62 {
  63         const char *err;
  64         struct cache_sb *s;
  65         struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
  66         unsigned int i;
  67
  68         if (!bh)
  69                 return "IO error";
  70
  71         s = (struct cache_sb *) bh->b_data;
  72
  73         sb->offset              = le64_to_cpu(s->offset);
  74         sb->version             = le64_to_cpu(s->version);
  75
  76         memcpy(sb->magic,       s->magic, 16);
  77         memcpy(sb->uuid,        s->uuid, 16);
  78         memcpy(sb->set_uuid,    s->set_uuid, 16);
  79         memcpy(sb->label,       s->label, SB_LABEL_SIZE);
  80
  81         sb->flags               = le64_to_cpu(s->flags);
  82         sb->seq                 = le64_to_cpu(s->seq);
  83         sb->last_mount          = le32_to_cpu(s->last_mount);
  84         sb->first_bucket        = le16_to_cpu(s->first_bucket);
  85         sb->keys                = le16_to_cpu(s->keys);
  86
  87         for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
  88                 sb->d[i] = le64_to_cpu(s->d[i]);
  89
  90         pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
  91                  sb->version, sb->flags, sb->seq, sb->keys);
  92
  93         err = "Not a bcache superblock";
  94         if (sb->offset != SB_SECTOR)
  95                 goto err;
  96
  97         if (memcmp(sb->magic, bcache_magic, 16))
  98                 goto err;
  99
 100         err = "Too many journal buckets";
 101         if (sb->keys > SB_JOURNAL_BUCKETS)
 102                 goto err;
 103
 104         err = "Bad checksum";
 105         if (s->csum != csum_set(s))
 106                 goto err;
 107
 108         err = "Bad UUID";
 109         if (bch_is_zero(sb->uuid, 16))
 110                 goto err;
 111
 112         sb->block_size  = le16_to_cpu(s->block_size);
 113
 114         err = "Superblock block size smaller than device block size";
 115         if (sb->block_size << 9 < bdev_logical_block_size(bdev))
 116                 goto err;
 117
 118         switch (sb->version) {
 119         case BCACHE_SB_VERSION_BDEV:
 120                 sb->data_offset = BDEV_DATA_START_DEFAULT;
 121                 break;
 122         case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
 123                 sb->data_offset = le64_to_cpu(s->data_offset);
 124
 125                 err = "Bad data offset";
 126                 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
 127                         goto err;
 128
 129                 break;
 130         case BCACHE_SB_VERSION_CDEV:
 131         case BCACHE_SB_VERSION_CDEV_WITH_UUID:
 132                 sb->nbuckets    = le64_to_cpu(s->nbuckets);
 133                 sb->bucket_size = le16_to_cpu(s->bucket_size);
 134
 135                 sb->nr_in_set   = le16_to_cpu(s->nr_in_set);
 136                 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
 137
 138                 err = "Too many buckets";
 139                 if (sb->nbuckets > LONG_MAX)
 140                         goto err;
 141
 142                 err = "Not enough buckets";
 143                 if (sb->nbuckets < 1 << 7)
 144                         goto err;
 145
 146                 err = "Bad block/bucket size";
 147                 if (!is_power_of_2(sb->block_size) ||
 148                     sb->block_size > PAGE_SECTORS ||
 149                     !is_power_of_2(sb->bucket_size) ||
 150                     sb->bucket_size < PAGE_SECTORS)
 151                         goto err;
 152
 153                 err = "Invalid superblock: device too small";
 154                 if (get_capacity(bdev->bd_disk) <
 155                     sb->bucket_size * sb->nbuckets)
 156                         goto err;
 157
 158                 err = "Bad UUID";
 159                 if (bch_is_zero(sb->set_uuid, 16))
 160                         goto err;
 161
 162                 err = "Bad cache device number in set";
 163                 if (!sb->nr_in_set ||
 164                     sb->nr_in_set <= sb->nr_this_dev ||
 165                     sb->nr_in_set > MAX_CACHES_PER_SET)
 166                         goto err;
 167
 168                 err = "Journal buckets not sequential";
 169                 for (i = 0; i < sb->keys; i++)
 170                         if (sb->d[i] != sb->first_bucket + i)
 171                                 goto err;
 172
 173                 err = "Too many journal buckets";
 174                 if (sb->first_bucket + sb->keys > sb->nbuckets)
 175                         goto err;
 176
 177                 err = "Invalid superblock: first bucket comes before end of super";
 178                 if (sb->first_bucket * sb->bucket_size < 16)
 179                         goto err;
 180
 181                 break;
 182         default:
 183                 err = "Unsupported superblock version";
 184                 goto err;
 185         }
 186
 187         sb->last_mount = (u32)ktime_get_real_seconds();
 188         err = NULL;
 189
 190         get_page(bh->b_page);
 191         *res = bh->b_page;
 192 err:
 193         put_bh(bh);
 194         return err;
 195 }
 196
 197 static void write_bdev_super_endio(struct bio *bio)
 198 {
 199         struct cached_dev *dc = bio->bi_private;
 200         /* XXX: error checking */
 201
 202         closure_put(&dc->sb_write);
 203 }
 204
 205 static void __write_super(struct cache_sb *sb, struct bio *bio)
 206 {
 207         struct cache_sb *out = page_address(bio_first_page_all(bio));
 208         unsigned int i;
 209
 210         bio->bi_iter.bi_sector  = SB_SECTOR;
 211         bio->bi_iter.bi_size    = SB_SIZE;
 212         bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META);
 213         bch_bio_map(bio, NULL);
 214
 215         out->offset             = cpu_to_le64(sb->offset);
 216         out->version            = cpu_to_le64(sb->version);
 217
 218         memcpy(out->uuid,       sb->uuid, 16);
 219         memcpy(out->set_uuid,   sb->set_uuid, 16);
 220         memcpy(out->label,      sb->label, SB_LABEL_SIZE);
 221
 222         out->flags              = cpu_to_le64(sb->flags);
 223         out->seq                = cpu_to_le64(sb->seq);
 224
 225         out->last_mount         = cpu_to_le32(sb->last_mount);
 226         out->first_bucket       = cpu_to_le16(sb->first_bucket);
 227         out->keys               = cpu_to_le16(sb->keys);
 228
 229         for (i = 0; i < sb->keys; i++)
 230                 out->d[i] = cpu_to_le64(sb->d[i]);
 231
 232         out->csum = csum_set(out);
 233
 234         pr_debug("ver %llu, flags %llu, seq %llu",
 235                  sb->version, sb->flags, sb->seq);
 236
 237         submit_bio(bio);
 238 }
 239
 240 static void bch_write_bdev_super_unlock(struct closure *cl)
 241 {
 242         struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
 243
 244         up(&dc->sb_write_mutex);
 245 }
 246
 247 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
 248 {
 249         struct closure *cl = &dc->sb_write;
 250         struct bio *bio = &dc->sb_bio;
 251
 252         down(&dc->sb_write_mutex);
 253         closure_init(cl, parent);
 254
 255         bio_reset(bio);
 256         bio_set_dev(bio, dc->bdev);
 257         bio->bi_end_io  = write_bdev_super_endio;
 258         bio->bi_private = dc;
 259
 260         closure_get(cl);
 261         /* I/O request sent to backing device */
 262         __write_super(&dc->sb, bio);
 263
 264         closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
 265 }
 266
 267 static void write_super_endio(struct bio *bio)
 268 {
 269         struct cache *ca = bio->bi_private;
 270
 271         /* is_read = 0 */
 272         bch_count_io_errors(ca, bio->bi_status, 0,
 273                             "writing superblock");
 274         closure_put(&ca->set->sb_write);
 275 }
 276
 277 static void bcache_write_super_unlock(struct closure *cl)
 278 {
 279         struct cache_set *c = container_of(cl, struct cache_set, sb_write);
 280
 281         up(&c->sb_write_mutex);
 282 }
 283
 284 void bcache_write_super(struct cache_set *c)
 285 {
 286         struct closure *cl = &c->sb_write;
 287         struct cache *ca;
 288         unsigned int i;
 289
 290         down(&c->sb_write_mutex);
 291         closure_init(cl, &c->cl);
 292
 293         c->sb.seq++;
 294
 295         for_each_cache(ca, c, i) {
 296                 struct bio *bio = &ca->sb_bio;
 297
 298                 ca->sb.version          = BCACHE_SB_VERSION_CDEV_WITH_UUID;
 299                 ca->sb.seq              = c->sb.seq;
 300                 ca->sb.last_mount       = c->sb.last_mount;
 301
 302                 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
 303
 304                 bio_reset(bio);
 305                 bio_set_dev(bio, ca->bdev);
 306                 bio->bi_end_io  = write_super_endio;
 307                 bio->bi_private = ca;
 308
 309                 closure_get(cl);
 310                 __write_super(&ca->sb, bio);
 311         }
 312
 313         closure_return_with_destructor(cl, bcache_write_super_unlock);
 314 }
 315
 316 /* UUID io */
 317
 318 static void uuid_endio(struct bio *bio)
 319 {
 320         struct closure *cl = bio->bi_private;
 321         struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
 322
 323         cache_set_err_on(bio->bi_status, c, "accessing uuids");
 324         bch_bbio_free(bio, c);
 325         closure_put(cl);
 326 }
 327
 328 static void uuid_io_unlock(struct closure *cl)
 329 {
 330         struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
 331
 332         up(&c->uuid_write_mutex);
 333 }
 334
 335 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
 336                     struct bkey *k, struct closure *parent)
 337 {
 338         struct closure *cl = &c->uuid_write;
 339         struct uuid_entry *u;
 340         unsigned int i;
 341         char buf[80];
 342
 343         BUG_ON(!parent);
 344         down(&c->uuid_write_mutex);
 345         closure_init(cl, parent);
 346
 347         for (i = 0; i < KEY_PTRS(k); i++) {
 348                 struct bio *bio = bch_bbio_alloc(c);
 349
 350                 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
 351                 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
 352
 353                 bio->bi_end_io  = uuid_endio;
 354                 bio->bi_private = cl;
 355                 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
 356                 bch_bio_map(bio, c->uuids);
 357
 358                 bch_submit_bbio(bio, c, k, i);
 359
 360                 if (op != REQ_OP_WRITE)
 361                         break;
 362         }
 363
 364         bch_extent_to_text(buf, sizeof(buf), k);
 365         pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf);
 366
 367         for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
 368                 if (!bch_is_zero(u->uuid, 16))
 369                         pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
 370                                  u - c->uuids, u->uuid, u->label,
 371                                  u->first_reg, u->last_reg, u->invalidated);
 372
 373         closure_return_with_destructor(cl, uuid_io_unlock);
 374 }
 375
 376 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
 377 {
 378         struct bkey *k = &j->uuid_bucket;
 379
 380         if (__bch_btree_ptr_invalid(c, k))
 381                 return "bad uuid pointer";
 382
 383         bkey_copy(&c->uuid_bucket, k);
 384         uuid_io(c, REQ_OP_READ, 0, k, cl);
 385
 386         if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
 387                 struct uuid_entry_v0    *u0 = (void *) c->uuids;
 388                 struct uuid_entry       *u1 = (void *) c->uuids;
 389                 int i;
 390
 391                 closure_sync(cl);
 392
 393                 /*
 394                  * Since the new uuid entry is bigger than the old, we have to
 395                  * convert starting at the highest memory address and work down
 396                  * in order to do it in place
 397                  */
 398
 399                 for (i = c->nr_uuids - 1;
 400                      i >= 0;
 401                      --i) {
 402                         memcpy(u1[i].uuid,      u0[i].uuid, 16);
 403                         memcpy(u1[i].label,     u0[i].label, 32);
 404
 405                         u1[i].first_reg         = u0[i].first_reg;
 406                         u1[i].last_reg          = u0[i].last_reg;
 407                         u1[i].invalidated       = u0[i].invalidated;
 408
 409                         u1[i].flags     = 0;
 410                         u1[i].sectors   = 0;
 411                 }
 412         }
 413
 414         return NULL;
 415 }
 416
 417 static int __uuid_write(struct cache_set *c)
 418 {
 419         BKEY_PADDED(key) k;
 420         struct closure cl;
 421         struct cache *ca;
 422
 423         closure_init_stack(&cl);
 424         lockdep_assert_held(&bch_register_lock);
 425
 426         if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
 427                 return 1;
 428
 429         SET_KEY_SIZE(&k.key, c->sb.bucket_size);
 430         uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
 431         closure_sync(&cl);
 432
 433         /* Only one bucket used for uuid write */
 434         ca = PTR_CACHE(c, &k.key, 0);
 435         atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
 436
 437         bkey_copy(&c->uuid_bucket, &k.key);
 438         bkey_put(c, &k.key);
 439         return 0;
 440 }
 441
 442 int bch_uuid_write(struct cache_set *c)
 443 {
 444         int ret = __uuid_write(c);
 445
 446         if (!ret)
 447                 bch_journal_meta(c, NULL);
 448
 449         return ret;
 450 }
 451
 452 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
 453 {
 454         struct uuid_entry *u;
 455
 456         for (u = c->uuids;
 457              u < c->uuids + c->nr_uuids; u++)
 458                 if (!memcmp(u->uuid, uuid, 16))
 459                         return u;
 460
 461         return NULL;
 462 }
 463
 464 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
 465 {
 466         static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
 467
 468         return uuid_find(c, zero_uuid);
 469 }
 470
 471 /*
 472  * Bucket priorities/gens:
 473  *
 474  * For each bucket, we store on disk its
 475  *   8 bit gen
 476  *  16 bit priority
 477  *
 478  * See alloc.c for an explanation of the gen. The priority is used to implement
 479  * lru (and in the future other) cache replacement policies; for most purposes
 480  * it's just an opaque integer.
 481  *
 482  * The gens and the priorities don't have a whole lot to do with each other, and
 483  * it's actually the gens that must be written out at specific times - it's no
 484  * big deal if the priorities don't get written, if we lose them we just reuse
 485  * buckets in suboptimal order.
 486  *
 487  * On disk they're stored in a packed array, and in as many buckets are required
 488  * to fit them all. The buckets we use to store them form a list; the journal
 489  * header points to the first bucket, the first bucket points to the second
 490  * bucket, et cetera.
 491  *
 492  * This code is used by the allocation code; periodically (whenever it runs out
 493  * of buckets to allocate from) the allocation code will invalidate some
 494  * buckets, but it can't use those buckets until their new gens are safely on
 495  * disk.
 496  */
 497
 498 static void prio_endio(struct bio *bio)
 499 {
 500         struct cache *ca = bio->bi_private;
 501
 502         cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
 503         bch_bbio_free(bio, ca->set);
 504         closure_put(&ca->prio);
 505 }
 506
 507 static void prio_io(struct cache *ca, uint64_t bucket, int op,
 508                     unsigned long op_flags)
 509 {
 510         struct closure *cl = &ca->prio;
 511         struct bio *bio = bch_bbio_alloc(ca->set);
 512
 513         closure_init_stack(cl);
 514
 515         bio->bi_iter.bi_sector  = bucket * ca->sb.bucket_size;
 516         bio_set_dev(bio, ca->bdev);
 517         bio->bi_iter.bi_size    = bucket_bytes(ca);
 518
 519         bio->bi_end_io  = prio_endio;
 520         bio->bi_private = ca;
 521         bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
 522         bch_bio_map(bio, ca->disk_buckets);
 523
 524         closure_bio_submit(ca->set, bio, &ca->prio);
 525         closure_sync(cl);
 526 }
 527
 528 int bch_prio_write(struct cache *ca, bool wait)
 529 {
 530         int i;
 531         struct bucket *b;
 532         struct closure cl;
 533
 534         pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu",
 535                  fifo_used(&ca->free[RESERVE_PRIO]),
 536                  fifo_used(&ca->free[RESERVE_NONE]),
 537                  fifo_used(&ca->free_inc));
 538
 539         /*
 540          * Pre-check if there are enough free buckets. In the non-blocking
 541          * scenario it's better to fail early rather than starting to allocate
 542          * buckets and do a cleanup later in case of failure.
 543          */
 544         if (!wait) {
 545                 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
 546                                fifo_used(&ca->free[RESERVE_NONE]);
 547                 if (prio_buckets(ca) > avail)
 548                         return -ENOMEM;
 549         }
 550
 551         closure_init_stack(&cl);
 552
 553         lockdep_assert_held(&ca->set->bucket_lock);
 554
 555         ca->disk_buckets->seq++;
 556
 557         atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
 558                         &ca->meta_sectors_written);
 559
 560         for (i = prio_buckets(ca) - 1; i >= 0; --i) {
 561                 long bucket;
 562                 struct prio_set *p = ca->disk_buckets;
 563                 struct bucket_disk *d = p->data;
 564                 struct bucket_disk *end = d + prios_per_bucket(ca);
 565
 566                 for (b = ca->buckets + i * prios_per_bucket(ca);
 567                      b < ca->buckets + ca->sb.nbuckets && d < end;
 568                      b++, d++) {
 569                         d->prio = cpu_to_le16(b->prio);
 570                         d->gen = b->gen;
 571                 }
 572
 573                 p->next_bucket  = ca->prio_buckets[i + 1];
 574                 p->magic        = pset_magic(&ca->sb);
 575                 p->csum         = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
 576
 577                 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
 578                 BUG_ON(bucket == -1);
 579
 580                 mutex_unlock(&ca->set->bucket_lock);
 581                 prio_io(ca, bucket, REQ_OP_WRITE, 0);
 582                 mutex_lock(&ca->set->bucket_lock);
 583
 584                 ca->prio_buckets[i] = bucket;
 585                 atomic_dec_bug(&ca->buckets[bucket].pin);
 586         }
 587
 588         mutex_unlock(&ca->set->bucket_lock);
 589
 590         bch_journal_meta(ca->set, &cl);
 591         closure_sync(&cl);
 592
 593         mutex_lock(&ca->set->bucket_lock);
 594
 595         /*
 596          * Don't want the old priorities to get garbage collected until after we
 597          * finish writing the new ones, and they're journalled
 598          */
 599         for (i = 0; i < prio_buckets(ca); i++) {
 600                 if (ca->prio_last_buckets[i])
 601                         __bch_bucket_free(ca,
 602                                 &ca->buckets[ca->prio_last_buckets[i]]);
 603
 604                 ca->prio_last_buckets[i] = ca->prio_buckets[i];
 605         }
 606         return 0;
 607 }
 608
 609 static void prio_read(struct cache *ca, uint64_t bucket)
 610 {
 611         struct prio_set *p = ca->disk_buckets;
 612         struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
 613         struct bucket *b;
 614         unsigned int bucket_nr = 0;
 615
 616         for (b = ca->buckets;
 617              b < ca->buckets + ca->sb.nbuckets;
 618              b++, d++) {
 619                 if (d == end) {
 620                         ca->prio_buckets[bucket_nr] = bucket;
 621                         ca->prio_last_buckets[bucket_nr] = bucket;
 622                         bucket_nr++;
 623
 624                         prio_io(ca, bucket, REQ_OP_READ, 0);
 625
 626                         if (p->csum !=
 627                             bch_crc64(&p->magic, bucket_bytes(ca) - 8))
 628                                 pr_warn("bad csum reading priorities");
 629
 630                         if (p->magic != pset_magic(&ca->sb))
 631                                 pr_warn("bad magic reading priorities");
 632
 633                         bucket = p->next_bucket;
 634                         d = p->data;
 635                 }
 636
 637                 b->prio = le16_to_cpu(d->prio);
 638                 b->gen = b->last_gc = d->gen;
 639         }
 640 }
 641
 642 /* Bcache device */
 643
 644 static int open_dev(struct block_device *b, fmode_t mode)
 645 {
 646         struct bcache_device *d = b->bd_disk->private_data;
 647
 648         if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
 649                 return -ENXIO;
 650
 651         closure_get(&d->cl);
 652         return 0;
 653 }
 654
 655 static void release_dev(struct gendisk *b, fmode_t mode)
 656 {
 657         struct bcache_device *d = b->private_data;
 658
 659         closure_put(&d->cl);
 660 }
 661
 662 static int ioctl_dev(struct block_device *b, fmode_t mode,
 663                      unsigned int cmd, unsigned long arg)
 664 {
 665         struct bcache_device *d = b->bd_disk->private_data;
 666
 667         return d->ioctl(d, mode, cmd, arg);
 668 }
 669
 670 static const struct block_device_operations bcache_ops = {
 671         .open           = open_dev,
 672         .release        = release_dev,
 673         .ioctl          = ioctl_dev,
 674         .owner          = THIS_MODULE,
 675 };
 676
 677 void bcache_device_stop(struct bcache_device *d)
 678 {
 679         if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
 680                 closure_queue(&d->cl);
 681 }
 682
 683 static void bcache_device_unlink(struct bcache_device *d)
 684 {
 685         lockdep_assert_held(&bch_register_lock);
 686
 687         if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
 688                 unsigned int i;
 689                 struct cache *ca;
 690
 691                 sysfs_remove_link(&d->c->kobj, d->name);
 692                 sysfs_remove_link(&d->kobj, "cache");
 693
 694                 for_each_cache(ca, d->c, i)
 695                         bd_unlink_disk_holder(ca->bdev, d->disk);
 696         }
 697 }
 698
 699 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
 700                                const char *name)
 701 {
 702         unsigned int i;
 703         struct cache *ca;
 704
 705         for_each_cache(ca, d->c, i)
 706                 bd_link_disk_holder(ca->bdev, d->disk);
 707
 708         snprintf(d->name, BCACHEDEVNAME_SIZE,
 709                  "%s%u", name, d->id);
 710
 711         WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
 712              sysfs_create_link(&c->kobj, &d->kobj, d->name),
 713              "Couldn't create device <-> cache set symlinks");
 714
 715         clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
 716 }
 717
 718 static void bcache_device_detach(struct bcache_device *d)
 719 {
 720         lockdep_assert_held(&bch_register_lock);
 721
 722         atomic_dec(&d->c->attached_dev_nr);
 723
 724         if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
 725                 struct uuid_entry *u = d->c->uuids + d->id;
 726
 727                 SET_UUID_FLASH_ONLY(u, 0);
 728                 memcpy(u->uuid, invalid_uuid, 16);
 729                 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
 730                 bch_uuid_write(d->c);
 731         }
 732
 733         bcache_device_unlink(d);
 734
 735         d->c->devices[d->id] = NULL;
 736         closure_put(&d->c->caching);
 737         d->c = NULL;
 738 }
 739
 740 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
 741                                  unsigned int id)
 742 {
 743         d->id = id;
 744         d->c = c;
 745         c->devices[id] = d;
 746
 747         if (id >= c->devices_max_used)
 748                 c->devices_max_used = id + 1;
 749
 750         closure_get(&c->caching);
 751 }
 752
 753 static inline int first_minor_to_idx(int first_minor)
 754 {
 755         return (first_minor/BCACHE_MINORS);
 756 }
 757
 758 static inline int idx_to_first_minor(int idx)
 759 {
 760         return (idx * BCACHE_MINORS);
 761 }
 762
 763 static void bcache_device_free(struct bcache_device *d)
 764 {
 765         struct gendisk *disk = d->disk;
 766
 767         lockdep_assert_held(&bch_register_lock);
 768
 769         if (disk)
 770                 pr_info("%s stopped", disk->disk_name);
 771         else
 772                 pr_err("bcache device (NULL gendisk) stopped");
 773
 774         if (d->c)
 775                 bcache_device_detach(d);
 776
 777         if (disk) {
 778                 bool disk_added = (disk->flags & GENHD_FL_UP) != 0;
 779
 780                 if (disk_added)
 781                         del_gendisk(disk);
 782
 783                 if (disk->queue)
 784                         blk_cleanup_queue(disk->queue);
 785
 786                 ida_simple_remove(&bcache_device_idx,
 787                                   first_minor_to_idx(disk->first_minor));
 788                 if (disk_added)
 789                         put_disk(disk);
 790         }
 791
 792         bioset_exit(&d->bio_split);
 793         kvfree(d->full_dirty_stripes);
 794         kvfree(d->stripe_sectors_dirty);
 795
 796         closure_debug_destroy(&d->cl);
 797 }
 798
 799 static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
 800                               sector_t sectors)
 801 {
 802         struct request_queue *q;
 803         const size_t max_stripes = min_t(size_t, INT_MAX,
 804                                          SIZE_MAX / sizeof(atomic_t));
 805         size_t n;
 806         int idx;
 807
 808         if (!d->stripe_size)
 809                 d->stripe_size = 1 << 31;
 810
 811         d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
 812
 813         if (!d->nr_stripes || d->nr_stripes > max_stripes) {
 814                 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)",
 815                         (unsigned int)d->nr_stripes);
 816                 return -ENOMEM;
 817         }
 818
 819         n = d->nr_stripes * sizeof(atomic_t);
 820         d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
 821         if (!d->stripe_sectors_dirty)
 822                 return -ENOMEM;
 823
 824         n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
 825         d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
 826         if (!d->full_dirty_stripes)
 827                 goto out_free_stripe_sectors_dirty;
 828
 829         idx = ida_simple_get(&bcache_device_idx, 0,
 830                                 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
 831         if (idx < 0)
 832                 goto out_free_full_dirty_stripes;
 833
 834         if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
 835                         BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
 836                 goto out_ida_remove;
 837
 838         d->disk = alloc_disk(BCACHE_MINORS);
 839         if (!d->disk)
 840                 goto out_bioset_exit;
 841
 842         set_capacity(d->disk, sectors);
 843         snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
 844
 845         d->disk->major          = bcache_major;
 846         d->disk->first_minor    = idx_to_first_minor(idx);
 847         d->disk->fops           = &bcache_ops;
 848         d->disk->private_data   = d;
 849
 850         q = blk_alloc_queue(GFP_KERNEL);
 851         if (!q)
 852                 return -ENOMEM;
 853
 854         blk_queue_make_request(q, NULL);
 855         d->disk->queue                  = q;
 856         q->queuedata                    = d;
 857         q->backing_dev_info->congested_data = d;
 858         q->limits.max_hw_sectors        = UINT_MAX;
 859         q->limits.max_sectors           = UINT_MAX;
 860         q->limits.max_segment_size      = UINT_MAX;
 861         q->limits.max_segments          = BIO_MAX_PAGES;
 862         blk_queue_max_discard_sectors(q, UINT_MAX);
 863         q->limits.discard_granularity   = 512;
 864         q->limits.io_min                = block_size;
 865         q->limits.logical_block_size    = block_size;
 866         q->limits.physical_block_size   = block_size;
 867         blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
 868         blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
 869         blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
 870
 871         blk_queue_write_cache(q, true, true);
 872
 873         return 0;
 874
 875 out_bioset_exit:
 876         bioset_exit(&d->bio_split);
 877 out_ida_remove:
 878         ida_simple_remove(&bcache_device_idx, idx);
 879 out_free_full_dirty_stripes:
 880         kvfree(d->full_dirty_stripes);
 881 out_free_stripe_sectors_dirty:
 882         kvfree(d->stripe_sectors_dirty);
 883         return -ENOMEM;
 884
 885 }
 886
 887 /* Cached device */
 888
 889 static void calc_cached_dev_sectors(struct cache_set *c)
 890 {
 891         uint64_t sectors = 0;
 892         struct cached_dev *dc;
 893
 894         list_for_each_entry(dc, &c->cached_devs, list)
 895                 sectors += bdev_sectors(dc->bdev);
 896
 897         c->cached_dev_sectors = sectors;
 898 }
 899
 900 #define BACKING_DEV_OFFLINE_TIMEOUT 5
 901 static int cached_dev_status_update(void *arg)
 902 {
 903         struct cached_dev *dc = arg;
 904         struct request_queue *q;
 905
 906         /*
 907          * If this delayed worker is stopping outside, directly quit here.
 908          * dc->io_disable might be set via sysfs interface, so check it
 909          * here too.
 910          */
 911         while (!kthread_should_stop() && !dc->io_disable) {
 912                 q = bdev_get_queue(dc->bdev);
 913                 if (blk_queue_dying(q))
 914                         dc->offline_seconds++;
 915                 else
 916                         dc->offline_seconds = 0;
 917
 918                 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
 919                         pr_err("%s: device offline for %d seconds",
 920                                dc->backing_dev_name,
 921                                BACKING_DEV_OFFLINE_TIMEOUT);
 922                         pr_err("%s: disable I/O request due to backing "
 923                                "device offline", dc->disk.name);
 924                         dc->io_disable = true;
 925                         /* let others know earlier that io_disable is true */
 926                         smp_mb();
 927                         bcache_device_stop(&dc->disk);
 928                         break;
 929                 }
 930                 schedule_timeout_interruptible(HZ);
 931         }
 932
 933         wait_for_kthread_stop();
 934         return 0;
 935 }
 936
 937
 938 void bch_cached_dev_run(struct cached_dev *dc)
 939 {
 940         struct bcache_device *d = &dc->disk;
 941         char buf[SB_LABEL_SIZE + 1];
 942         char *env[] = {
 943                 "DRIVER=bcache",
 944                 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
 945                 NULL,
 946                 NULL,
 947         };
 948
 949         memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
 950         buf[SB_LABEL_SIZE] = '\0';
 951         env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf);
 952
 953         if (atomic_xchg(&dc->running, 1)) {
 954                 kfree(env[1]);
 955                 kfree(env[2]);
 956                 return;
 957         }
 958
 959         if (!d->c &&
 960             BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
 961                 struct closure cl;
 962
 963                 closure_init_stack(&cl);
 964
 965                 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
 966                 bch_write_bdev_super(dc, &cl);
 967                 closure_sync(&cl);
 968         }
 969
 970         add_disk(d->disk);
 971         bd_link_disk_holder(dc->bdev, dc->disk.disk);
 972         /*
 973          * won't show up in the uevent file, use udevadm monitor -e instead
 974          * only class / kset properties are persistent
 975          */
 976         kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
 977         kfree(env[1]);
 978         kfree(env[2]);
 979
 980         if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
 981             sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
 982                 pr_debug("error creating sysfs link");
 983
 984         dc->status_update_thread = kthread_run(cached_dev_status_update,
 985                                                dc, "bcache_status_update");
 986         if (IS_ERR(dc->status_update_thread)) {
 987                 pr_warn("failed to create bcache_status_update kthread, "
 988                         "continue to run without monitoring backing "
 989                         "device status");
 990         }
 991 }
 992
 993 /*
 994  * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
 995  * work dc->writeback_rate_update is running. Wait until the routine
 996  * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
 997  * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
 998  * seconds, give up waiting here and continue to cancel it too.
 999  */
1000 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1001 {
1002         int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1003
1004         do {
1005                 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1006                               &dc->disk.flags))
1007                         break;
1008                 time_out--;
1009                 schedule_timeout_interruptible(1);
1010         } while (time_out > 0);
1011
1012         if (time_out == 0)
1013                 pr_warn("give up waiting for dc->writeback_write_update to quit");
1014
1015         cancel_delayed_work_sync(&dc->writeback_rate_update);
1016 }
1017
1018 static void cached_dev_detach_finish(struct work_struct *w)
1019 {
1020         struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1021         struct closure cl;
1022
1023         closure_init_stack(&cl);
1024
1025         BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1026         BUG_ON(refcount_read(&dc->count));
1027
1028         mutex_lock(&bch_register_lock);
1029
1030         if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1031                 cancel_writeback_rate_update_dwork(dc);
1032
1033         if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1034                 kthread_stop(dc->writeback_thread);
1035                 dc->writeback_thread = NULL;
1036         }
1037
1038         memset(&dc->sb.set_uuid, 0, 16);
1039         SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
1040
1041         bch_write_bdev_super(dc, &cl);
1042         closure_sync(&cl);
1043
1044         calc_cached_dev_sectors(dc->disk.c);
1045         bcache_device_detach(&dc->disk);
1046         list_move(&dc->list, &uncached_devices);
1047
1048         clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1049         clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1050
1051         mutex_unlock(&bch_register_lock);
1052
1053         pr_info("Caching disabled for %s", dc->backing_dev_name);
1054
1055         /* Drop ref we took in cached_dev_detach() */
1056         closure_put(&dc->disk.cl);
1057 }
1058
1059 void bch_cached_dev_detach(struct cached_dev *dc)
1060 {
1061         lockdep_assert_held(&bch_register_lock);
1062
1063         if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1064                 return;
1065
1066         if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1067                 return;
1068
1069         /*
1070          * Block the device from being closed and freed until we're finished
1071          * detaching
1072          */
1073         closure_get(&dc->disk.cl);
1074
1075         bch_writeback_queue(dc);
1076
1077         cached_dev_put(dc);
1078 }
1079
1080 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1081                           uint8_t *set_uuid)
1082 {
1083         uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1084         struct uuid_entry *u;
1085         struct cached_dev *exist_dc, *t;
1086
1087         if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
1088             (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
1089                 return -ENOENT;
1090
1091         if (dc->disk.c) {
1092                 pr_err("Can't attach %s: already attached",
1093                        dc->backing_dev_name);
1094                 return -EINVAL;
1095         }
1096
1097         if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1098                 pr_err("Can't attach %s: shutting down",
1099                        dc->backing_dev_name);
1100                 return -EINVAL;
1101         }
1102
1103         if (dc->sb.block_size < c->sb.block_size) {
1104                 /* Will die */
1105                 pr_err("Couldn't attach %s: block size less than set's block size",
1106                        dc->backing_dev_name);
1107                 return -EINVAL;
1108         }
1109
1110         /* Check whether already attached */
1111         list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1112                 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1113                         pr_err("Tried to attach %s but duplicate UUID already attached",
1114                                 dc->backing_dev_name);
1115
1116                         return -EINVAL;
1117                 }
1118         }
1119
1120         u = uuid_find(c, dc->sb.uuid);
1121
1122         if (u &&
1123             (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1124              BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1125                 memcpy(u->uuid, invalid_uuid, 16);
1126                 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1127                 u = NULL;
1128         }
1129
1130         if (!u) {
1131                 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1132                         pr_err("Couldn't find uuid for %s in set",
1133                                dc->backing_dev_name);
1134                         return -ENOENT;
1135                 }
1136
1137                 u = uuid_find_empty(c);
1138                 if (!u) {
1139                         pr_err("Not caching %s, no room for UUID",
1140                                dc->backing_dev_name);
1141                         return -EINVAL;
1142                 }
1143         }
1144
1145         /*
1146          * Deadlocks since we're called via sysfs...
1147          * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1148          */
1149
1150         if (bch_is_zero(u->uuid, 16)) {
1151                 struct closure cl;
1152
1153                 closure_init_stack(&cl);
1154
1155                 memcpy(u->uuid, dc->sb.uuid, 16);
1156                 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1157                 u->first_reg = u->last_reg = rtime;
1158                 bch_uuid_write(c);
1159
1160                 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
1161                 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1162
1163                 bch_write_bdev_super(dc, &cl);
1164                 closure_sync(&cl);
1165         } else {
1166                 u->last_reg = rtime;
1167                 bch_uuid_write(c);
1168         }
1169
1170         bcache_device_attach(&dc->disk, c, u - c->uuids);
1171         list_move(&dc->list, &c->cached_devs);
1172         calc_cached_dev_sectors(c);
1173
1174         /*
1175          * dc->c must be set before dc->count != 0 - paired with the mb in
1176          * cached_dev_get()
1177          */
1178         smp_wmb();
1179         refcount_set(&dc->count, 1);
1180
1181         /* Block writeback thread, but spawn it */
1182         down_write(&dc->writeback_lock);
1183         if (bch_cached_dev_writeback_start(dc)) {
1184                 up_write(&dc->writeback_lock);
1185                 return -ENOMEM;
1186         }
1187
1188         if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1189                 atomic_set(&dc->has_dirty, 1);
1190                 bch_writeback_queue(dc);
1191         }
1192
1193         bch_sectors_dirty_init(&dc->disk);
1194
1195         bch_cached_dev_run(dc);
1196         bcache_device_link(&dc->disk, c, "bdev");
1197         atomic_inc(&c->attached_dev_nr);
1198
1199         /* Allow the writeback thread to proceed */
1200         up_write(&dc->writeback_lock);
1201
1202         pr_info("Caching %s as %s on set %pU",
1203                 dc->backing_dev_name,
1204                 dc->disk.disk->disk_name,
1205                 dc->disk.c->sb.set_uuid);
1206         return 0;
1207 }
1208
1209 void bch_cached_dev_release(struct kobject *kobj)
1210 {
1211         struct cached_dev *dc = container_of(kobj, struct cached_dev,
1212                                              disk.kobj);
1213         kfree(dc);
1214         module_put(THIS_MODULE);
1215 }
1216
1217 static void cached_dev_free(struct closure *cl)
1218 {
1219         struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1220
1221         if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1222                 cancel_writeback_rate_update_dwork(dc);
1223
1224         if (!IS_ERR_OR_NULL(dc->writeback_thread))
1225                 kthread_stop(dc->writeback_thread);
1226         if (!IS_ERR_OR_NULL(dc->status_update_thread))
1227                 kthread_stop(dc->status_update_thread);
1228
1229         mutex_lock(&bch_register_lock);
1230
1231         if (atomic_read(&dc->running))
1232                 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1233         bcache_device_free(&dc->disk);
1234         list_del(&dc->list);
1235
1236         mutex_unlock(&bch_register_lock);
1237
1238         if (dc->sb_bio.bi_inline_vecs[0].bv_page)
1239                 put_page(bio_first_page_all(&dc->sb_bio));
1240
1241         if (!IS_ERR_OR_NULL(dc->bdev))
1242                 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1243
1244         wake_up(&unregister_wait);
1245
1246         kobject_put(&dc->disk.kobj);
1247 }
1248
1249 static void cached_dev_flush(struct closure *cl)
1250 {
1251         struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1252         struct bcache_device *d = &dc->disk;
1253
1254         mutex_lock(&bch_register_lock);
1255         bcache_device_unlink(d);
1256         mutex_unlock(&bch_register_lock);
1257
1258         bch_cache_accounting_destroy(&dc->accounting);
1259         kobject_del(&d->kobj);
1260
1261         continue_at(cl, cached_dev_free, system_wq);
1262 }
1263
1264 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1265 {
1266         int ret;
1267         struct io *io;
1268         struct request_queue *q = bdev_get_queue(dc->bdev);
1269
1270         __module_get(THIS_MODULE);
1271         INIT_LIST_HEAD(&dc->list);
1272         closure_init(&dc->disk.cl, NULL);
1273         set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1274         kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1275         INIT_WORK(&dc->detach, cached_dev_detach_finish);
1276         sema_init(&dc->sb_write_mutex, 1);
1277         INIT_LIST_HEAD(&dc->io_lru);
1278         spin_lock_init(&dc->io_lock);
1279         bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1280
1281         dc->sequential_cutoff           = 4 << 20;
1282
1283         for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1284                 list_add(&io->lru, &dc->io_lru);
1285                 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1286         }
1287
1288         dc->disk.stripe_size = q->limits.io_opt >> 9;
1289
1290         if (dc->disk.stripe_size)
1291                 dc->partial_stripes_expensive =
1292                         q->limits.raid_partial_stripes_expensive;
1293
1294         ret = bcache_device_init(&dc->disk, block_size,
1295                          dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
1296         if (ret)
1297                 return ret;
1298
1299         dc->disk.disk->queue->backing_dev_info->ra_pages =
1300                 max(dc->disk.disk->queue->backing_dev_info->ra_pages,
1301                     q->backing_dev_info->ra_pages);
1302
1303         atomic_set(&dc->io_errors, 0);
1304         dc->io_disable = false;
1305         dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1306         /* default to auto */
1307         dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1308
1309         bch_cached_dev_request_init(dc);
1310         bch_cached_dev_writeback_init(dc);
1311         return 0;
1312 }
1313
1314 /* Cached device - bcache superblock */
1315
1316 static void register_bdev(struct cache_sb *sb, struct page *sb_page,
1317                                  struct block_device *bdev,
1318                                  struct cached_dev *dc)
1319 {
1320         const char *err = "cannot allocate memory";
1321         struct cache_set *c;
1322
1323         bdevname(bdev, dc->backing_dev_name);
1324         memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1325         dc->bdev = bdev;
1326         dc->bdev->bd_holder = dc;
1327
1328         bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1);
1329         bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page;
1330         get_page(sb_page);
1331
1332
1333         if (cached_dev_init(dc, sb->block_size << 9))
1334                 goto err;
1335
1336         err = "error creating kobject";
1337         if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1338                         "bcache"))
1339                 goto err;
1340         if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1341                 goto err;
1342
1343         pr_info("registered backing device %s", dc->backing_dev_name);
1344
1345         list_add(&dc->list, &uncached_devices);
1346         /* attach to a matched cache set if it exists */
1347         list_for_each_entry(c, &bch_cache_sets, list)
1348                 bch_cached_dev_attach(dc, c, NULL);
1349
1350         if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1351             BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
1352                 bch_cached_dev_run(dc);
1353
1354         return;
1355 err:
1356         pr_notice("error %s: %s", dc->backing_dev_name, err);
1357         bcache_device_stop(&dc->disk);
1358 }
1359
1360 /* Flash only volumes */
1361
1362 void bch_flash_dev_release(struct kobject *kobj)
1363 {
1364         struct bcache_device *d = container_of(kobj, struct bcache_device,
1365                                                kobj);
1366         kfree(d);
1367 }
1368
1369 static void flash_dev_free(struct closure *cl)
1370 {
1371         struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1372
1373         mutex_lock(&bch_register_lock);
1374         atomic_long_sub(bcache_dev_sectors_dirty(d),
1375                         &d->c->flash_dev_dirty_sectors);
1376         bcache_device_free(d);
1377         mutex_unlock(&bch_register_lock);
1378         kobject_put(&d->kobj);
1379 }
1380
1381 static void flash_dev_flush(struct closure *cl)
1382 {
1383         struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1384
1385         mutex_lock(&bch_register_lock);
1386         bcache_device_unlink(d);
1387         mutex_unlock(&bch_register_lock);
1388         kobject_del(&d->kobj);
1389         continue_at(cl, flash_dev_free, system_wq);
1390 }
1391
1392 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1393 {
1394         struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1395                                           GFP_KERNEL);
1396         if (!d)
1397                 return -ENOMEM;
1398
1399         closure_init(&d->cl, NULL);
1400         set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1401
1402         kobject_init(&d->kobj, &bch_flash_dev_ktype);
1403
1404         if (bcache_device_init(d, block_bytes(c), u->sectors))
1405                 goto err;
1406
1407         bcache_device_attach(d, c, u - c->uuids);
1408         bch_sectors_dirty_init(d);
1409         bch_flash_dev_request_init(d);
1410         add_disk(d->disk);
1411
1412         if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1413                 goto err;
1414
1415         bcache_device_link(d, c, "volume");
1416
1417         return 0;
1418 err:
1419         kobject_put(&d->kobj);
1420         return -ENOMEM;
1421 }
1422
1423 static int flash_devs_run(struct cache_set *c)
1424 {
1425         int ret = 0;
1426         struct uuid_entry *u;
1427
1428         for (u = c->uuids;
1429              u < c->uuids + c->nr_uuids && !ret;
1430              u++)
1431                 if (UUID_FLASH_ONLY(u))
1432                         ret = flash_dev_run(c, u);
1433
1434         return ret;
1435 }
1436
1437 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1438 {
1439         struct uuid_entry *u;
1440
1441         if (test_bit(CACHE_SET_STOPPING, &c->flags))
1442                 return -EINTR;
1443
1444         if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1445                 return -EPERM;
1446
1447         u = uuid_find_empty(c);
1448         if (!u) {
1449                 pr_err("Can't create volume, no room for UUID");
1450                 return -EINVAL;
1451         }
1452
1453         get_random_bytes(u->uuid, 16);
1454         memset(u->label, 0, 32);
1455         u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1456
1457         SET_UUID_FLASH_ONLY(u, 1);
1458         u->sectors = size >> 9;
1459
1460         bch_uuid_write(c);
1461
1462         return flash_dev_run(c, u);
1463 }
1464
1465 bool bch_cached_dev_error(struct cached_dev *dc)
1466 {
1467         if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1468                 return false;
1469
1470         dc->io_disable = true;
1471         /* make others know io_disable is true earlier */
1472         smp_mb();
1473
1474         pr_err("stop %s: too many IO errors on backing device %s\n",
1475                 dc->disk.disk->disk_name, dc->backing_dev_name);
1476
1477         bcache_device_stop(&dc->disk);
1478         return true;
1479 }
1480
1481 /* Cache set */
1482
1483 __printf(2, 3)
1484 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1485 {
1486         va_list args;
1487
1488         if (c->on_error != ON_ERROR_PANIC &&
1489             test_bit(CACHE_SET_STOPPING, &c->flags))
1490                 return false;
1491
1492         if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1493                 pr_info("CACHE_SET_IO_DISABLE already set");
1494
1495         /*
1496          * XXX: we can be called from atomic context
1497          * acquire_console_sem();
1498          */
1499
1500         pr_err("bcache: error on %pU: ", c->sb.set_uuid);
1501
1502         va_start(args, fmt);
1503         vprintk(fmt, args);
1504         va_end(args);
1505
1506         pr_err(", disabling caching\n");
1507
1508         if (c->on_error == ON_ERROR_PANIC)
1509                 panic("panic forced after error\n");
1510
1511         bch_cache_set_unregister(c);
1512         return true;
1513 }
1514
1515 void bch_cache_set_release(struct kobject *kobj)
1516 {
1517         struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1518
1519         kfree(c);
1520         module_put(THIS_MODULE);
1521 }
1522
1523 static void cache_set_free(struct closure *cl)
1524 {
1525         struct cache_set *c = container_of(cl, struct cache_set, cl);
1526         struct cache *ca;
1527         unsigned int i;
1528
1529         debugfs_remove(c->debug);
1530
1531         bch_open_buckets_free(c);
1532         bch_btree_cache_free(c);
1533         bch_journal_free(c);
1534
1535         mutex_lock(&bch_register_lock);
1536         for_each_cache(ca, c, i)
1537                 if (ca) {
1538                         ca->set = NULL;
1539                         c->cache[ca->sb.nr_this_dev] = NULL;
1540                         kobject_put(&ca->kobj);
1541                 }
1542
1543         bch_bset_sort_state_free(&c->sort);
1544         free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
1545
1546         if (c->moving_gc_wq)
1547                 destroy_workqueue(c->moving_gc_wq);
1548         bioset_exit(&c->bio_split);
1549         mempool_exit(&c->fill_iter);
1550         mempool_exit(&c->bio_meta);
1551         mempool_exit(&c->search);
1552         kfree(c->devices);
1553
1554         list_del(&c->list);
1555         mutex_unlock(&bch_register_lock);
1556
1557         pr_info("Cache set %pU unregistered", c->sb.set_uuid);
1558         wake_up(&unregister_wait);
1559
1560         closure_debug_destroy(&c->cl);
1561         kobject_put(&c->kobj);
1562 }
1563
1564 static void cache_set_flush(struct closure *cl)
1565 {
1566         struct cache_set *c = container_of(cl, struct cache_set, caching);
1567         struct cache *ca;
1568         struct btree *b;
1569         unsigned int i;
1570
1571         bch_cache_accounting_destroy(&c->accounting);
1572
1573         kobject_put(&c->internal);
1574         kobject_del(&c->kobj);
1575
1576         if (!IS_ERR_OR_NULL(c->gc_thread))
1577                 kthread_stop(c->gc_thread);
1578
1579         if (!IS_ERR_OR_NULL(c->root))
1580                 list_add(&c->root->list, &c->btree_cache);
1581
1582         /* Should skip this if we're unregistering because of an error */
1583         list_for_each_entry(b, &c->btree_cache, list) {
1584                 mutex_lock(&b->write_lock);
1585                 if (btree_node_dirty(b))
1586                         __bch_btree_node_write(b, NULL);
1587                 mutex_unlock(&b->write_lock);
1588         }
1589
1590         for_each_cache(ca, c, i)
1591                 if (ca->alloc_thread)
1592                         kthread_stop(ca->alloc_thread);
1593
1594         if (c->journal.cur) {
1595                 cancel_delayed_work_sync(&c->journal.work);
1596                 /* flush last journal entry if needed */
1597                 c->journal.work.work.func(&c->journal.work.work);
1598         }
1599
1600         closure_return(cl);
1601 }
1602
1603 /*
1604  * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1605  * cache set is unregistering due to too many I/O errors. In this condition,
1606  * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1607  * value and whether the broken cache has dirty data:
1608  *
1609  * dc->stop_when_cache_set_failed    dc->has_dirty   stop bcache device
1610  *  BCH_CACHED_STOP_AUTO               0               NO
1611  *  BCH_CACHED_STOP_AUTO               1               YES
1612  *  BCH_CACHED_DEV_STOP_ALWAYS         0               YES
1613  *  BCH_CACHED_DEV_STOP_ALWAYS         1               YES
1614  *
1615  * The expected behavior is, if stop_when_cache_set_failed is configured to
1616  * "auto" via sysfs interface, the bcache device will not be stopped if the
1617  * backing device is clean on the broken cache device.
1618  */
1619 static void conditional_stop_bcache_device(struct cache_set *c,
1620                                            struct bcache_device *d,
1621                                            struct cached_dev *dc)
1622 {
1623         if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1624                 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.",
1625                         d->disk->disk_name, c->sb.set_uuid);
1626                 bcache_device_stop(d);
1627         } else if (atomic_read(&dc->has_dirty)) {
1628                 /*
1629                  * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1630                  * and dc->has_dirty == 1
1631                  */
1632                 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.",
1633                         d->disk->disk_name);
1634                         /*
1635                          * There might be a small time gap that cache set is
1636                          * released but bcache device is not. Inside this time
1637                          * gap, regular I/O requests will directly go into
1638                          * backing device as no cache set attached to. This
1639                          * behavior may also introduce potential inconsistence
1640                          * data in writeback mode while cache is dirty.
1641                          * Therefore before calling bcache_device_stop() due
1642                          * to a broken cache device, dc->io_disable should be
1643                          * explicitly set to true.
1644                          */
1645                         dc->io_disable = true;
1646                         /* make others know io_disable is true earlier */
1647                         smp_mb();
1648                         bcache_device_stop(d);
1649         } else {
1650                 /*
1651                  * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1652                  * and dc->has_dirty == 0
1653                  */
1654                 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.",
1655                         d->disk->disk_name);
1656         }
1657 }
1658
1659 static void __cache_set_unregister(struct closure *cl)
1660 {
1661         struct cache_set *c = container_of(cl, struct cache_set, caching);
1662         struct cached_dev *dc;
1663         struct bcache_device *d;
1664         size_t i;
1665
1666         mutex_lock(&bch_register_lock);
1667
1668         for (i = 0; i < c->devices_max_used; i++) {
1669                 d = c->devices[i];
1670                 if (!d)
1671                         continue;
1672
1673                 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1674                     test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1675                         dc = container_of(d, struct cached_dev, disk);
1676                         bch_cached_dev_detach(dc);
1677                         if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1678                                 conditional_stop_bcache_device(c, d, dc);
1679                 } else {
1680                         bcache_device_stop(d);
1681                 }
1682         }
1683
1684         mutex_unlock(&bch_register_lock);
1685
1686         continue_at(cl, cache_set_flush, system_wq);
1687 }
1688
1689 void bch_cache_set_stop(struct cache_set *c)
1690 {
1691         if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1692                 closure_queue(&c->caching);
1693 }
1694
1695 void bch_cache_set_unregister(struct cache_set *c)
1696 {
1697         set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1698         bch_cache_set_stop(c);
1699 }
1700
1701 #define alloc_bucket_pages(gfp, c)                      \
1702         ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(bucket_pages(c))))
1703
1704 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1705 {
1706         int iter_size;
1707         struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1708
1709         if (!c)
1710                 return NULL;
1711
1712         __module_get(THIS_MODULE);
1713         closure_init(&c->cl, NULL);
1714         set_closure_fn(&c->cl, cache_set_free, system_wq);
1715
1716         closure_init(&c->caching, &c->cl);
1717         set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1718
1719         /* Maybe create continue_at_noreturn() and use it here? */
1720         closure_set_stopped(&c->cl);
1721         closure_put(&c->cl);
1722
1723         kobject_init(&c->kobj, &bch_cache_set_ktype);
1724         kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1725
1726         bch_cache_accounting_init(&c->accounting, &c->cl);
1727
1728         memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1729         c->sb.block_size        = sb->block_size;
1730         c->sb.bucket_size       = sb->bucket_size;
1731         c->sb.nr_in_set         = sb->nr_in_set;
1732         c->sb.last_mount        = sb->last_mount;
1733         c->bucket_bits          = ilog2(sb->bucket_size);
1734         c->block_bits           = ilog2(sb->block_size);
1735         c->nr_uuids             = bucket_bytes(c) / sizeof(struct uuid_entry);
1736         c->devices_max_used     = 0;
1737         atomic_set(&c->attached_dev_nr, 0);
1738         c->btree_pages          = bucket_pages(c);
1739         if (c->btree_pages > BTREE_MAX_PAGES)
1740                 c->btree_pages = max_t(int, c->btree_pages / 4,
1741                                        BTREE_MAX_PAGES);
1742
1743         sema_init(&c->sb_write_mutex, 1);
1744         mutex_init(&c->bucket_lock);
1745         init_waitqueue_head(&c->btree_cache_wait);
1746         spin_lock_init(&c->btree_cannibalize_lock);
1747         init_waitqueue_head(&c->bucket_wait);
1748         init_waitqueue_head(&c->gc_wait);
1749         sema_init(&c->uuid_write_mutex, 1);
1750
1751         spin_lock_init(&c->btree_gc_time.lock);
1752         spin_lock_init(&c->btree_split_time.lock);
1753         spin_lock_init(&c->btree_read_time.lock);
1754
1755         bch_moving_init_cache_set(c);
1756
1757         INIT_LIST_HEAD(&c->list);
1758         INIT_LIST_HEAD(&c->cached_devs);
1759         INIT_LIST_HEAD(&c->btree_cache);
1760         INIT_LIST_HEAD(&c->btree_cache_freeable);
1761         INIT_LIST_HEAD(&c->btree_cache_freed);
1762         INIT_LIST_HEAD(&c->data_buckets);
1763
1764         iter_size = (sb->bucket_size / sb->block_size + 1) *
1765                 sizeof(struct btree_iter_set);
1766
1767         if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) ||
1768             mempool_init_slab_pool(&c->search, 32, bch_search_cache) ||
1769             mempool_init_kmalloc_pool(&c->bio_meta, 2,
1770                                 sizeof(struct bbio) + sizeof(struct bio_vec) *
1771                                 bucket_pages(c)) ||
1772             mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
1773             bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1774                         BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) ||
1775             !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
1776             !(c->moving_gc_wq = alloc_workqueue("bcache_gc",
1777                                                 WQ_MEM_RECLAIM, 0)) ||
1778             bch_journal_alloc(c) ||
1779             bch_btree_cache_alloc(c) ||
1780             bch_open_buckets_alloc(c) ||
1781             bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1782                 goto err;
1783
1784         c->congested_read_threshold_us  = 2000;
1785         c->congested_write_threshold_us = 20000;
1786         c->error_limit  = DEFAULT_IO_ERROR_LIMIT;
1787         WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1788
1789         return c;
1790 err:
1791         bch_cache_set_unregister(c);
1792         return NULL;
1793 }
1794
1795 static int run_cache_set(struct cache_set *c)
1796 {
1797         const char *err = "cannot allocate memory";
1798         struct cached_dev *dc, *t;
1799         struct cache *ca;
1800         struct closure cl;
1801         unsigned int i;
1802         LIST_HEAD(journal);
1803         struct journal_replay *l;
1804
1805         closure_init_stack(&cl);
1806
1807         for_each_cache(ca, c, i)
1808                 c->nbuckets += ca->sb.nbuckets;
1809         set_gc_sectors(c);
1810
1811         if (CACHE_SYNC(&c->sb)) {
1812                 struct bkey *k;
1813                 struct jset *j;
1814
1815                 err = "cannot allocate memory for journal";
1816                 if (bch_journal_read(c, &journal))
1817                         goto err;
1818
1819                 pr_debug("btree_journal_read() done");
1820
1821                 err = "no journal entries found";
1822                 if (list_empty(&journal))
1823                         goto err;
1824
1825                 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1826
1827                 err = "IO error reading priorities";
1828                 for_each_cache(ca, c, i)
1829                         prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]);
1830
1831                 /*
1832                  * If prio_read() fails it'll call cache_set_error and we'll
1833                  * tear everything down right away, but if we perhaps checked
1834                  * sooner we could avoid journal replay.
1835                  */
1836
1837                 k = &j->btree_root;
1838
1839                 err = "bad btree root";
1840                 if (__bch_btree_ptr_invalid(c, k))
1841                         goto err;
1842
1843                 err = "error reading btree root";
1844                 c->root = bch_btree_node_get(c, NULL, k,
1845                                              j->btree_level,
1846                                              true, NULL);
1847                 if (IS_ERR_OR_NULL(c->root))
1848                         goto err;
1849
1850                 list_del_init(&c->root->list);
1851                 rw_unlock(true, c->root);
1852
1853                 err = uuid_read(c, j, &cl);
1854                 if (err)
1855                         goto err;
1856
1857                 err = "error in recovery";
1858                 if (bch_btree_check(c))
1859                         goto err;
1860
1861                 bch_journal_mark(c, &journal);
1862                 bch_initial_gc_finish(c);
1863                 pr_debug("btree_check() done");
1864
1865                 /*
1866                  * bcache_journal_next() can't happen sooner, or
1867                  * btree_gc_finish() will give spurious errors about last_gc >
1868                  * gc_gen - this is a hack but oh well.
1869                  */
1870                 bch_journal_next(&c->journal);
1871
1872                 err = "error starting allocator thread";
1873                 for_each_cache(ca, c, i)
1874                         if (bch_cache_allocator_start(ca))
1875                                 goto err;
1876
1877                 /*
1878                  * First place it's safe to allocate: btree_check() and
1879                  * btree_gc_finish() have to run before we have buckets to
1880                  * allocate, and bch_bucket_alloc_set() might cause a journal
1881                  * entry to be written so bcache_journal_next() has to be called
1882                  * first.
1883                  *
1884                  * If the uuids were in the old format we have to rewrite them
1885                  * before the next journal entry is written:
1886                  */
1887                 if (j->version < BCACHE_JSET_VERSION_UUID)
1888                         __uuid_write(c);
1889
1890                 err = "bcache: replay journal failed";
1891                 if (bch_journal_replay(c, &journal))
1892                         goto err;
1893         } else {
1894                 pr_notice("invalidating existing data");
1895
1896                 for_each_cache(ca, c, i) {
1897                         unsigned int j;
1898
1899                         ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
1900                                               2, SB_JOURNAL_BUCKETS);
1901
1902                         for (j = 0; j < ca->sb.keys; j++)
1903                                 ca->sb.d[j] = ca->sb.first_bucket + j;
1904                 }
1905
1906                 bch_initial_gc_finish(c);
1907
1908                 err = "error starting allocator thread";
1909                 for_each_cache(ca, c, i)
1910                         if (bch_cache_allocator_start(ca))
1911                                 goto err;
1912
1913                 mutex_lock(&c->bucket_lock);
1914                 for_each_cache(ca, c, i)
1915                         bch_prio_write(ca, true);
1916                 mutex_unlock(&c->bucket_lock);
1917
1918                 err = "cannot allocate new UUID bucket";
1919                 if (__uuid_write(c))
1920                         goto err;
1921
1922                 err = "cannot allocate new btree root";
1923                 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
1924                 if (IS_ERR_OR_NULL(c->root))
1925                         goto err;
1926
1927                 mutex_lock(&c->root->write_lock);
1928                 bkey_copy_key(&c->root->key, &MAX_KEY);
1929                 bch_btree_node_write(c->root, &cl);
1930                 mutex_unlock(&c->root->write_lock);
1931
1932                 bch_btree_set_root(c->root);
1933                 rw_unlock(true, c->root);
1934
1935                 /*
1936                  * We don't want to write the first journal entry until
1937                  * everything is set up - fortunately journal entries won't be
1938                  * written until the SET_CACHE_SYNC() here:
1939                  */
1940                 SET_CACHE_SYNC(&c->sb, true);
1941
1942                 bch_journal_next(&c->journal);
1943                 bch_journal_meta(c, &cl);
1944         }
1945
1946         err = "error starting gc thread";
1947         if (bch_gc_thread_start(c))
1948                 goto err;
1949
1950         closure_sync(&cl);
1951         c->sb.last_mount = (u32)ktime_get_real_seconds();
1952         bcache_write_super(c);
1953
1954         list_for_each_entry_safe(dc, t, &uncached_devices, list)
1955                 bch_cached_dev_attach(dc, c, NULL);
1956
1957         flash_devs_run(c);
1958
1959         set_bit(CACHE_SET_RUNNING, &c->flags);
1960         return 0;
1961 err:
1962         while (!list_empty(&journal)) {
1963                 l = list_first_entry(&journal, struct journal_replay, list);
1964                 list_del(&l->list);
1965                 kfree(l);
1966         }
1967
1968         closure_sync(&cl);
1969         /* XXX: test this, it's broken */
1970         bch_cache_set_error(c, "%s", err);
1971
1972         return -EIO;
1973 }
1974
1975 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
1976 {
1977         return ca->sb.block_size        == c->sb.block_size &&
1978                 ca->sb.bucket_size      == c->sb.bucket_size &&
1979                 ca->sb.nr_in_set        == c->sb.nr_in_set;
1980 }
1981
1982 static const char *register_cache_set(struct cache *ca)
1983 {
1984         char buf[12];
1985         const char *err = "cannot allocate memory";
1986         struct cache_set *c;
1987
1988         list_for_each_entry(c, &bch_cache_sets, list)
1989                 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
1990                         if (c->cache[ca->sb.nr_this_dev])
1991                                 return "duplicate cache set member";
1992
1993                         if (!can_attach_cache(ca, c))
1994                                 return "cache sb does not match set";
1995
1996                         if (!CACHE_SYNC(&ca->sb))
1997                                 SET_CACHE_SYNC(&c->sb, false);
1998
1999                         goto found;
2000                 }
2001
2002         c = bch_cache_set_alloc(&ca->sb);
2003         if (!c)
2004                 return err;
2005
2006         err = "error creating kobject";
2007         if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
2008             kobject_add(&c->internal, &c->kobj, "internal"))
2009                 goto err;
2010
2011         if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2012                 goto err;
2013
2014         bch_debug_init_cache_set(c);
2015
2016         list_add(&c->list, &bch_cache_sets);
2017 found:
2018         sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2019         if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2020             sysfs_create_link(&c->kobj, &ca->kobj, buf))
2021                 goto err;
2022
2023         /*
2024          * A special case is both ca->sb.seq and c->sb.seq are 0,
2025          * such condition happens on a new created cache device whose
2026          * super block is never flushed yet. In this case c->sb.version
2027          * and other members should be updated too, otherwise we will
2028          * have a mistaken super block version in cache set.
2029          */
2030         if (ca->sb.seq > c->sb.seq || c->sb.seq == 0) {
2031                 c->sb.version           = ca->sb.version;
2032                 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2033                 c->sb.flags             = ca->sb.flags;
2034                 c->sb.seq               = ca->sb.seq;
2035                 pr_debug("set version = %llu", c->sb.version);
2036         }
2037
2038         kobject_get(&ca->kobj);
2039         ca->set = c;
2040         ca->set->cache[ca->sb.nr_this_dev] = ca;
2041         c->cache_by_alloc[c->caches_loaded++] = ca;
2042
2043         if (c->caches_loaded == c->sb.nr_in_set) {
2044                 err = "failed to run cache set";
2045                 if (run_cache_set(c) < 0)
2046                         goto err;
2047         }
2048
2049         return NULL;
2050 err:
2051         bch_cache_set_unregister(c);
2052         return err;
2053 }
2054
2055 /* Cache device */
2056
2057 void bch_cache_release(struct kobject *kobj)
2058 {
2059         struct cache *ca = container_of(kobj, struct cache, kobj);
2060         unsigned int i;
2061
2062         if (ca->set) {
2063                 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca);
2064                 ca->set->cache[ca->sb.nr_this_dev] = NULL;
2065         }
2066
2067         free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
2068         kfree(ca->prio_buckets);
2069         vfree(ca->buckets);
2070
2071         free_heap(&ca->heap);
2072         free_fifo(&ca->free_inc);
2073
2074         for (i = 0; i < RESERVE_NR; i++)
2075                 free_fifo(&ca->free[i]);
2076
2077         if (ca->sb_bio.bi_inline_vecs[0].bv_page)
2078                 put_page(bio_first_page_all(&ca->sb_bio));
2079
2080         if (!IS_ERR_OR_NULL(ca->bdev))
2081                 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2082
2083         kfree(ca);
2084         module_put(THIS_MODULE);
2085 }
2086
2087 static int cache_alloc(struct cache *ca)
2088 {
2089         size_t free;
2090         size_t btree_buckets;
2091         struct bucket *b;
2092
2093         __module_get(THIS_MODULE);
2094         kobject_init(&ca->kobj, &bch_cache_ktype);
2095
2096         bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2097
2098         /*
2099          * when ca->sb.njournal_buckets is not zero, journal exists,
2100          * and in bch_journal_replay(), tree node may split,
2101          * so bucket of RESERVE_BTREE type is needed,
2102          * the worst situation is all journal buckets are valid journal,
2103          * and all the keys need to replay,
2104          * so the number of  RESERVE_BTREE type buckets should be as much
2105          * as journal buckets
2106          */
2107         btree_buckets = ca->sb.njournal_buckets ?: 8;
2108         free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2109
2110         if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) ||
2111             !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) ||
2112             !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) ||
2113             !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) ||
2114             !init_fifo(&ca->free_inc,   free << 2, GFP_KERNEL) ||
2115             !init_heap(&ca->heap,       free << 3, GFP_KERNEL) ||
2116             !(ca->buckets       = vzalloc(array_size(sizeof(struct bucket),
2117                                                      ca->sb.nbuckets))) ||
2118             !(ca->prio_buckets  = kzalloc(array3_size(sizeof(uint64_t),
2119                                                       prio_buckets(ca), 2),
2120                                           GFP_KERNEL)) ||
2121             !(ca->disk_buckets  = alloc_bucket_pages(GFP_KERNEL, ca)))
2122                 return -ENOMEM;
2123
2124         ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2125
2126         for_each_bucket(b, ca)
2127                 atomic_set(&b->pin, 0);
2128
2129         return 0;
2130 }
2131
2132 static int register_cache(struct cache_sb *sb, struct page *sb_page,
2133                                 struct block_device *bdev, struct cache *ca)
2134 {
2135         const char *err = NULL; /* must be set for any error case */
2136         int ret = 0;
2137
2138         bdevname(bdev, ca->cache_dev_name);
2139         memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2140         ca->bdev = bdev;
2141         ca->bdev->bd_holder = ca;
2142
2143         bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1);
2144         bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page;
2145         get_page(sb_page);
2146
2147         if (blk_queue_discard(bdev_get_queue(bdev)))
2148                 ca->discard = CACHE_DISCARD(&ca->sb);
2149
2150         ret = cache_alloc(ca);
2151         if (ret != 0) {
2152                 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2153                 if (ret == -ENOMEM)
2154                         err = "cache_alloc(): -ENOMEM";
2155                 else
2156                         err = "cache_alloc(): unknown error";
2157                 goto err;
2158         }
2159
2160         if (kobject_add(&ca->kobj,
2161                         &part_to_dev(bdev->bd_part)->kobj,
2162                         "bcache")) {
2163                 err = "error calling kobject_add";
2164                 ret = -ENOMEM;
2165                 goto out;
2166         }
2167
2168         mutex_lock(&bch_register_lock);
2169         err = register_cache_set(ca);
2170         mutex_unlock(&bch_register_lock);
2171
2172         if (err) {
2173                 ret = -ENODEV;
2174                 goto out;
2175         }
2176
2177         pr_info("registered cache device %s", ca->cache_dev_name);
2178
2179 out:
2180         kobject_put(&ca->kobj);
2181
2182 err:
2183         if (err)
2184                 pr_notice("error %s: %s", ca->cache_dev_name, err);
2185
2186         return ret;
2187 }
2188
2189 /* Global interfaces/init */
2190
2191 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2192                                const char *buffer, size_t size);
2193
2194 kobj_attribute_write(register,          register_bcache);
2195 kobj_attribute_write(register_quiet,    register_bcache);
2196
2197 static bool bch_is_open_backing(struct block_device *bdev)
2198 {
2199         struct cache_set *c, *tc;
2200         struct cached_dev *dc, *t;
2201
2202         list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2203                 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2204                         if (dc->bdev == bdev)
2205                                 return true;
2206         list_for_each_entry_safe(dc, t, &uncached_devices, list)
2207                 if (dc->bdev == bdev)
2208                         return true;
2209         return false;
2210 }
2211
2212 static bool bch_is_open_cache(struct block_device *bdev)
2213 {
2214         struct cache_set *c, *tc;
2215         struct cache *ca;
2216         unsigned int i;
2217
2218         list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2219                 for_each_cache(ca, c, i)
2220                         if (ca->bdev == bdev)
2221                                 return true;
2222         return false;
2223 }
2224
2225 static bool bch_is_open(struct block_device *bdev)
2226 {
2227         return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
2228 }
2229
2230 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2231                                const char *buffer, size_t size)
2232 {
2233         ssize_t ret = size;
2234         const char *err = "cannot allocate memory";
2235         char *path = NULL;
2236         struct cache_sb *sb = NULL;
2237         struct block_device *bdev = NULL;
2238         struct page *sb_page = NULL;
2239
2240         if (!try_module_get(THIS_MODULE))
2241                 return -EBUSY;
2242
2243         path = kstrndup(buffer, size, GFP_KERNEL);
2244         if (!path)
2245                 goto err;
2246
2247         sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2248         if (!sb)
2249                 goto err;
2250
2251         err = "failed to open device";
2252         bdev = blkdev_get_by_path(strim(path),
2253                                   FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2254                                   sb);
2255         if (IS_ERR(bdev)) {
2256                 if (bdev == ERR_PTR(-EBUSY)) {
2257                         bdev = lookup_bdev(strim(path));
2258                         mutex_lock(&bch_register_lock);
2259                         if (!IS_ERR(bdev) && bch_is_open(bdev))
2260                                 err = "device already registered";
2261                         else
2262                                 err = "device busy";
2263                         mutex_unlock(&bch_register_lock);
2264                         if (!IS_ERR(bdev))
2265                                 bdput(bdev);
2266                         if (attr == &ksysfs_register_quiet)
2267                                 goto out;
2268                 }
2269                 goto err;
2270         }
2271
2272         err = "failed to set blocksize";
2273         if (set_blocksize(bdev, 4096))
2274                 goto err_close;
2275
2276         err = read_super(sb, bdev, &sb_page);
2277         if (err)
2278                 goto err_close;
2279
2280         err = "failed to register device";
2281         if (SB_IS_BDEV(sb)) {
2282                 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2283
2284                 if (!dc)
2285                         goto err_close;
2286
2287                 mutex_lock(&bch_register_lock);
2288                 register_bdev(sb, sb_page, bdev, dc);
2289                 mutex_unlock(&bch_register_lock);
2290         } else {
2291                 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2292
2293                 if (!ca)
2294                         goto err_close;
2295
2296                 if (register_cache(sb, sb_page, bdev, ca) != 0)
2297                         goto err;
2298         }
2299 out:
2300         if (sb_page)
2301                 put_page(sb_page);
2302         kfree(sb);
2303         kfree(path);
2304         module_put(THIS_MODULE);
2305         return ret;
2306
2307 err_close:
2308         blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2309 err:
2310         pr_info("error %s: %s", path, err);
2311         ret = -EINVAL;
2312         goto out;
2313 }
2314
2315 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2316 {
2317         if (code == SYS_DOWN ||
2318             code == SYS_HALT ||
2319             code == SYS_POWER_OFF) {
2320                 DEFINE_WAIT(wait);
2321                 unsigned long start = jiffies;
2322                 bool stopped = false;
2323
2324                 struct cache_set *c, *tc;
2325                 struct cached_dev *dc, *tdc;
2326
2327                 mutex_lock(&bch_register_lock);
2328
2329                 if (list_empty(&bch_cache_sets) &&
2330                     list_empty(&uncached_devices))
2331                         goto out;
2332
2333                 pr_info("Stopping all devices:");
2334
2335                 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2336                         bch_cache_set_stop(c);
2337
2338                 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2339                         bcache_device_stop(&dc->disk);
2340
2341                 /* What's a condition variable? */
2342                 while (1) {
2343                         long timeout = start + 2 * HZ - jiffies;
2344
2345                         stopped = list_empty(&bch_cache_sets) &&
2346                                 list_empty(&uncached_devices);
2347
2348                         if (timeout < 0 || stopped)
2349                                 break;
2350
2351                         prepare_to_wait(&unregister_wait, &wait,
2352                                         TASK_UNINTERRUPTIBLE);
2353
2354                         mutex_unlock(&bch_register_lock);
2355                         schedule_timeout(timeout);
2356                         mutex_lock(&bch_register_lock);
2357                 }
2358
2359                 finish_wait(&unregister_wait, &wait);
2360
2361                 if (stopped)
2362                         pr_info("All devices stopped");
2363                 else
2364                         pr_notice("Timeout waiting for devices to be closed");
2365 out:
2366                 mutex_unlock(&bch_register_lock);
2367         }
2368
2369         return NOTIFY_DONE;
2370 }
2371
2372 static struct notifier_block reboot = {
2373         .notifier_call  = bcache_reboot,
2374         .priority       = INT_MAX, /* before any real devices */
2375 };
2376
2377 static void bcache_exit(void)
2378 {
2379         bch_debug_exit();
2380         bch_request_exit();
2381         if (bcache_kobj)
2382                 kobject_put(bcache_kobj);
2383         if (bcache_wq)
2384                 destroy_workqueue(bcache_wq);
2385         if (bch_journal_wq)
2386                 destroy_workqueue(bch_journal_wq);
2387
2388         if (bcache_major)
2389                 unregister_blkdev(bcache_major, "bcache");
2390         unregister_reboot_notifier(&reboot);
2391         mutex_destroy(&bch_register_lock);
2392 }
2393
2394 static int __init bcache_init(void)
2395 {
2396         static const struct attribute *files[] = {
2397                 &ksysfs_register.attr,
2398                 &ksysfs_register_quiet.attr,
2399                 NULL
2400         };
2401
2402         mutex_init(&bch_register_lock);
2403         init_waitqueue_head(&unregister_wait);
2404         register_reboot_notifier(&reboot);
2405
2406         bcache_major = register_blkdev(0, "bcache");
2407         if (bcache_major < 0) {
2408                 unregister_reboot_notifier(&reboot);
2409                 mutex_destroy(&bch_register_lock);
2410                 return bcache_major;
2411         }
2412
2413         bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2414         if (!bcache_wq)
2415                 goto err;
2416
2417         bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2418         if (!bch_journal_wq)
2419                 goto err;
2420
2421         bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2422         if (!bcache_kobj)
2423                 goto err;
2424
2425         if (bch_request_init() ||
2426             sysfs_create_files(bcache_kobj, files))
2427                 goto err;
2428
2429         bch_debug_init(bcache_kobj);
2430         closure_debug_init();
2431
2432         return 0;
2433 err:
2434         bcache_exit();
2435         return -ENOMEM;
2436 }
2437
2438 module_exit(bcache_exit);
2439 module_init(bcache_init);