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