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->bucket_size = le16_to_cpu(s->bucket_size); 138 139 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 140 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 141 142 err = "Too many buckets"; 143 if (sb->nbuckets > LONG_MAX) 144 goto err; 145 146 err = "Not enough buckets"; 147 if (sb->nbuckets < 1 << 7) 148 goto err; 149 150 err = "Bad block/bucket size"; 151 if (!is_power_of_2(sb->block_size) || 152 sb->block_size > PAGE_SECTORS || 153 !is_power_of_2(sb->bucket_size) || 154 sb->bucket_size < PAGE_SECTORS) 155 goto err; 156 157 err = "Invalid superblock: device too small"; 158 if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets) 159 goto err; 160 161 err = "Bad UUID"; 162 if (bch_is_zero(sb->set_uuid, 16)) 163 goto err; 164 165 err = "Bad cache device number in set"; 166 if (!sb->nr_in_set || 167 sb->nr_in_set <= sb->nr_this_dev || 168 sb->nr_in_set > MAX_CACHES_PER_SET) 169 goto err; 170 171 err = "Journal buckets not sequential"; 172 for (i = 0; i < sb->keys; i++) 173 if (sb->d[i] != sb->first_bucket + i) 174 goto err; 175 176 err = "Too many journal buckets"; 177 if (sb->first_bucket + sb->keys > sb->nbuckets) 178 goto err; 179 180 err = "Invalid superblock: first bucket comes before end of super"; 181 if (sb->first_bucket * sb->bucket_size < 16) 182 goto err; 183 184 break; 185 default: 186 err = "Unsupported superblock version"; 187 goto err; 188 } 189 190 sb->last_mount = get_seconds(); 191 err = NULL; 192 193 get_page(bh->b_page); 194 *res = bh->b_page; 195 err: 196 put_bh(bh); 197 return err; 198 } 199 200 static void write_bdev_super_endio(struct bio *bio) 201 { 202 struct cached_dev *dc = bio->bi_private; 203 /* XXX: error checking */ 204 205 closure_put(&dc->sb_write); 206 } 207 208 static void __write_super(struct cache_sb *sb, struct bio *bio) 209 { 210 struct cache_sb *out = page_address(bio->bi_io_vec[0].bv_page); 211 unsigned i; 212 213 bio->bi_iter.bi_sector = SB_SECTOR; 214 bio->bi_iter.bi_size = SB_SIZE; 215 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 216 bch_bio_map(bio, NULL); 217 218 out->offset = cpu_to_le64(sb->offset); 219 out->version = cpu_to_le64(sb->version); 220 221 memcpy(out->uuid, sb->uuid, 16); 222 memcpy(out->set_uuid, sb->set_uuid, 16); 223 memcpy(out->label, sb->label, SB_LABEL_SIZE); 224 225 out->flags = cpu_to_le64(sb->flags); 226 out->seq = cpu_to_le64(sb->seq); 227 228 out->last_mount = cpu_to_le32(sb->last_mount); 229 out->first_bucket = cpu_to_le16(sb->first_bucket); 230 out->keys = cpu_to_le16(sb->keys); 231 232 for (i = 0; i < sb->keys; i++) 233 out->d[i] = cpu_to_le64(sb->d[i]); 234 235 out->csum = csum_set(out); 236 237 pr_debug("ver %llu, flags %llu, seq %llu", 238 sb->version, sb->flags, sb->seq); 239 240 submit_bio(bio); 241 } 242 243 static void bch_write_bdev_super_unlock(struct closure *cl) 244 { 245 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 246 247 up(&dc->sb_write_mutex); 248 } 249 250 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 251 { 252 struct closure *cl = &dc->sb_write; 253 struct bio *bio = &dc->sb_bio; 254 255 down(&dc->sb_write_mutex); 256 closure_init(cl, parent); 257 258 bio_reset(bio); 259 bio->bi_bdev = dc->bdev; 260 bio->bi_end_io = write_bdev_super_endio; 261 bio->bi_private = dc; 262 263 closure_get(cl); 264 __write_super(&dc->sb, bio); 265 266 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 267 } 268 269 static void write_super_endio(struct bio *bio) 270 { 271 struct cache *ca = bio->bi_private; 272 273 bch_count_io_errors(ca, bio->bi_error, "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 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->bi_bdev = 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_error, 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 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, 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_OP_WRITE, 0, &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, int op, 502 unsigned long op_flags) 503 { 504 struct closure *cl = &ca->prio; 505 struct bio *bio = bch_bbio_alloc(ca->set); 506 507 closure_init_stack(cl); 508 509 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 510 bio->bi_bdev = ca->bdev; 511 bio->bi_iter.bi_size = bucket_bytes(ca); 512 513 bio->bi_end_io = prio_endio; 514 bio->bi_private = ca; 515 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 516 bch_bio_map(bio, ca->disk_buckets); 517 518 closure_bio_submit(bio, &ca->prio); 519 closure_sync(cl); 520 } 521 522 void bch_prio_write(struct cache *ca) 523 { 524 int i; 525 struct bucket *b; 526 struct closure cl; 527 528 closure_init_stack(&cl); 529 530 lockdep_assert_held(&ca->set->bucket_lock); 531 532 ca->disk_buckets->seq++; 533 534 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 535 &ca->meta_sectors_written); 536 537 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 538 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 539 540 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 541 long bucket; 542 struct prio_set *p = ca->disk_buckets; 543 struct bucket_disk *d = p->data; 544 struct bucket_disk *end = d + prios_per_bucket(ca); 545 546 for (b = ca->buckets + i * prios_per_bucket(ca); 547 b < ca->buckets + ca->sb.nbuckets && d < end; 548 b++, d++) { 549 d->prio = cpu_to_le16(b->prio); 550 d->gen = b->gen; 551 } 552 553 p->next_bucket = ca->prio_buckets[i + 1]; 554 p->magic = pset_magic(&ca->sb); 555 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 556 557 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 558 BUG_ON(bucket == -1); 559 560 mutex_unlock(&ca->set->bucket_lock); 561 prio_io(ca, bucket, REQ_OP_WRITE, 0); 562 mutex_lock(&ca->set->bucket_lock); 563 564 ca->prio_buckets[i] = bucket; 565 atomic_dec_bug(&ca->buckets[bucket].pin); 566 } 567 568 mutex_unlock(&ca->set->bucket_lock); 569 570 bch_journal_meta(ca->set, &cl); 571 closure_sync(&cl); 572 573 mutex_lock(&ca->set->bucket_lock); 574 575 /* 576 * Don't want the old priorities to get garbage collected until after we 577 * finish writing the new ones, and they're journalled 578 */ 579 for (i = 0; i < prio_buckets(ca); i++) { 580 if (ca->prio_last_buckets[i]) 581 __bch_bucket_free(ca, 582 &ca->buckets[ca->prio_last_buckets[i]]); 583 584 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 585 } 586 } 587 588 static void prio_read(struct cache *ca, uint64_t bucket) 589 { 590 struct prio_set *p = ca->disk_buckets; 591 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 592 struct bucket *b; 593 unsigned bucket_nr = 0; 594 595 for (b = ca->buckets; 596 b < ca->buckets + ca->sb.nbuckets; 597 b++, d++) { 598 if (d == end) { 599 ca->prio_buckets[bucket_nr] = bucket; 600 ca->prio_last_buckets[bucket_nr] = bucket; 601 bucket_nr++; 602 603 prio_io(ca, bucket, REQ_OP_READ, READ_SYNC); 604 605 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 606 pr_warn("bad csum reading priorities"); 607 608 if (p->magic != pset_magic(&ca->sb)) 609 pr_warn("bad magic reading priorities"); 610 611 bucket = p->next_bucket; 612 d = p->data; 613 } 614 615 b->prio = le16_to_cpu(d->prio); 616 b->gen = b->last_gc = d->gen; 617 } 618 } 619 620 /* Bcache device */ 621 622 static int open_dev(struct block_device *b, fmode_t mode) 623 { 624 struct bcache_device *d = b->bd_disk->private_data; 625 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 626 return -ENXIO; 627 628 closure_get(&d->cl); 629 return 0; 630 } 631 632 static void release_dev(struct gendisk *b, fmode_t mode) 633 { 634 struct bcache_device *d = b->private_data; 635 closure_put(&d->cl); 636 } 637 638 static int ioctl_dev(struct block_device *b, fmode_t mode, 639 unsigned int cmd, unsigned long arg) 640 { 641 struct bcache_device *d = b->bd_disk->private_data; 642 return d->ioctl(d, mode, cmd, arg); 643 } 644 645 static const struct block_device_operations bcache_ops = { 646 .open = open_dev, 647 .release = release_dev, 648 .ioctl = ioctl_dev, 649 .owner = THIS_MODULE, 650 }; 651 652 void bcache_device_stop(struct bcache_device *d) 653 { 654 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 655 closure_queue(&d->cl); 656 } 657 658 static void bcache_device_unlink(struct bcache_device *d) 659 { 660 lockdep_assert_held(&bch_register_lock); 661 662 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 663 unsigned i; 664 struct cache *ca; 665 666 sysfs_remove_link(&d->c->kobj, d->name); 667 sysfs_remove_link(&d->kobj, "cache"); 668 669 for_each_cache(ca, d->c, i) 670 bd_unlink_disk_holder(ca->bdev, d->disk); 671 } 672 } 673 674 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 675 const char *name) 676 { 677 unsigned i; 678 struct cache *ca; 679 680 for_each_cache(ca, d->c, i) 681 bd_link_disk_holder(ca->bdev, d->disk); 682 683 snprintf(d->name, BCACHEDEVNAME_SIZE, 684 "%s%u", name, d->id); 685 686 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 687 sysfs_create_link(&c->kobj, &d->kobj, d->name), 688 "Couldn't create device <-> cache set symlinks"); 689 690 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 691 } 692 693 static void bcache_device_detach(struct bcache_device *d) 694 { 695 lockdep_assert_held(&bch_register_lock); 696 697 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 698 struct uuid_entry *u = d->c->uuids + d->id; 699 700 SET_UUID_FLASH_ONLY(u, 0); 701 memcpy(u->uuid, invalid_uuid, 16); 702 u->invalidated = cpu_to_le32(get_seconds()); 703 bch_uuid_write(d->c); 704 } 705 706 bcache_device_unlink(d); 707 708 d->c->devices[d->id] = NULL; 709 closure_put(&d->c->caching); 710 d->c = NULL; 711 } 712 713 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 714 unsigned id) 715 { 716 d->id = id; 717 d->c = c; 718 c->devices[id] = d; 719 720 closure_get(&c->caching); 721 } 722 723 static void bcache_device_free(struct bcache_device *d) 724 { 725 lockdep_assert_held(&bch_register_lock); 726 727 pr_info("%s stopped", d->disk->disk_name); 728 729 if (d->c) 730 bcache_device_detach(d); 731 if (d->disk && d->disk->flags & GENHD_FL_UP) 732 del_gendisk(d->disk); 733 if (d->disk && d->disk->queue) 734 blk_cleanup_queue(d->disk->queue); 735 if (d->disk) { 736 ida_simple_remove(&bcache_minor, d->disk->first_minor); 737 put_disk(d->disk); 738 } 739 740 if (d->bio_split) 741 bioset_free(d->bio_split); 742 kvfree(d->full_dirty_stripes); 743 kvfree(d->stripe_sectors_dirty); 744 745 closure_debug_destroy(&d->cl); 746 } 747 748 static int bcache_device_init(struct bcache_device *d, unsigned block_size, 749 sector_t sectors) 750 { 751 struct request_queue *q; 752 size_t n; 753 int minor; 754 755 if (!d->stripe_size) 756 d->stripe_size = 1 << 31; 757 758 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 759 760 if (!d->nr_stripes || 761 d->nr_stripes > INT_MAX || 762 d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) { 763 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 764 (unsigned)d->nr_stripes); 765 return -ENOMEM; 766 } 767 768 n = d->nr_stripes * sizeof(atomic_t); 769 d->stripe_sectors_dirty = n < PAGE_SIZE << 6 770 ? kzalloc(n, GFP_KERNEL) 771 : vzalloc(n); 772 if (!d->stripe_sectors_dirty) 773 return -ENOMEM; 774 775 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 776 d->full_dirty_stripes = n < PAGE_SIZE << 6 777 ? kzalloc(n, GFP_KERNEL) 778 : vzalloc(n); 779 if (!d->full_dirty_stripes) 780 return -ENOMEM; 781 782 minor = ida_simple_get(&bcache_minor, 0, MINORMASK + 1, GFP_KERNEL); 783 if (minor < 0) 784 return minor; 785 786 if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) || 787 !(d->disk = alloc_disk(1))) { 788 ida_simple_remove(&bcache_minor, minor); 789 return -ENOMEM; 790 } 791 792 set_capacity(d->disk, sectors); 793 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", minor); 794 795 d->disk->major = bcache_major; 796 d->disk->first_minor = minor; 797 d->disk->fops = &bcache_ops; 798 d->disk->private_data = d; 799 800 q = blk_alloc_queue(GFP_KERNEL); 801 if (!q) 802 return -ENOMEM; 803 804 blk_queue_make_request(q, NULL); 805 d->disk->queue = q; 806 q->queuedata = d; 807 q->backing_dev_info.congested_data = d; 808 q->limits.max_hw_sectors = UINT_MAX; 809 q->limits.max_sectors = UINT_MAX; 810 q->limits.max_segment_size = UINT_MAX; 811 q->limits.max_segments = BIO_MAX_PAGES; 812 blk_queue_max_discard_sectors(q, UINT_MAX); 813 q->limits.discard_granularity = 512; 814 q->limits.io_min = block_size; 815 q->limits.logical_block_size = block_size; 816 q->limits.physical_block_size = block_size; 817 set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags); 818 clear_bit(QUEUE_FLAG_ADD_RANDOM, &d->disk->queue->queue_flags); 819 set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags); 820 821 blk_queue_write_cache(q, true, true); 822 823 return 0; 824 } 825 826 /* Cached device */ 827 828 static void calc_cached_dev_sectors(struct cache_set *c) 829 { 830 uint64_t sectors = 0; 831 struct cached_dev *dc; 832 833 list_for_each_entry(dc, &c->cached_devs, list) 834 sectors += bdev_sectors(dc->bdev); 835 836 c->cached_dev_sectors = sectors; 837 } 838 839 void bch_cached_dev_run(struct cached_dev *dc) 840 { 841 struct bcache_device *d = &dc->disk; 842 char buf[SB_LABEL_SIZE + 1]; 843 char *env[] = { 844 "DRIVER=bcache", 845 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 846 NULL, 847 NULL, 848 }; 849 850 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 851 buf[SB_LABEL_SIZE] = '\0'; 852 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 853 854 if (atomic_xchg(&dc->running, 1)) { 855 kfree(env[1]); 856 kfree(env[2]); 857 return; 858 } 859 860 if (!d->c && 861 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 862 struct closure cl; 863 closure_init_stack(&cl); 864 865 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 866 bch_write_bdev_super(dc, &cl); 867 closure_sync(&cl); 868 } 869 870 add_disk(d->disk); 871 bd_link_disk_holder(dc->bdev, dc->disk.disk); 872 /* won't show up in the uevent file, use udevadm monitor -e instead 873 * only class / kset properties are persistent */ 874 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 875 kfree(env[1]); 876 kfree(env[2]); 877 878 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 879 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 880 pr_debug("error creating sysfs link"); 881 } 882 883 static void cached_dev_detach_finish(struct work_struct *w) 884 { 885 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 886 char buf[BDEVNAME_SIZE]; 887 struct closure cl; 888 closure_init_stack(&cl); 889 890 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 891 BUG_ON(atomic_read(&dc->count)); 892 893 mutex_lock(&bch_register_lock); 894 895 memset(&dc->sb.set_uuid, 0, 16); 896 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 897 898 bch_write_bdev_super(dc, &cl); 899 closure_sync(&cl); 900 901 bcache_device_detach(&dc->disk); 902 list_move(&dc->list, &uncached_devices); 903 904 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 905 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 906 907 mutex_unlock(&bch_register_lock); 908 909 pr_info("Caching disabled for %s", bdevname(dc->bdev, buf)); 910 911 /* Drop ref we took in cached_dev_detach() */ 912 closure_put(&dc->disk.cl); 913 } 914 915 void bch_cached_dev_detach(struct cached_dev *dc) 916 { 917 lockdep_assert_held(&bch_register_lock); 918 919 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 920 return; 921 922 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 923 return; 924 925 /* 926 * Block the device from being closed and freed until we're finished 927 * detaching 928 */ 929 closure_get(&dc->disk.cl); 930 931 bch_writeback_queue(dc); 932 cached_dev_put(dc); 933 } 934 935 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c) 936 { 937 uint32_t rtime = cpu_to_le32(get_seconds()); 938 struct uuid_entry *u; 939 char buf[BDEVNAME_SIZE]; 940 941 bdevname(dc->bdev, buf); 942 943 if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)) 944 return -ENOENT; 945 946 if (dc->disk.c) { 947 pr_err("Can't attach %s: already attached", buf); 948 return -EINVAL; 949 } 950 951 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 952 pr_err("Can't attach %s: shutting down", buf); 953 return -EINVAL; 954 } 955 956 if (dc->sb.block_size < c->sb.block_size) { 957 /* Will die */ 958 pr_err("Couldn't attach %s: block size less than set's block size", 959 buf); 960 return -EINVAL; 961 } 962 963 u = uuid_find(c, dc->sb.uuid); 964 965 if (u && 966 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 967 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 968 memcpy(u->uuid, invalid_uuid, 16); 969 u->invalidated = cpu_to_le32(get_seconds()); 970 u = NULL; 971 } 972 973 if (!u) { 974 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 975 pr_err("Couldn't find uuid for %s in set", buf); 976 return -ENOENT; 977 } 978 979 u = uuid_find_empty(c); 980 if (!u) { 981 pr_err("Not caching %s, no room for UUID", buf); 982 return -EINVAL; 983 } 984 } 985 986 /* Deadlocks since we're called via sysfs... 987 sysfs_remove_file(&dc->kobj, &sysfs_attach); 988 */ 989 990 if (bch_is_zero(u->uuid, 16)) { 991 struct closure cl; 992 closure_init_stack(&cl); 993 994 memcpy(u->uuid, dc->sb.uuid, 16); 995 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 996 u->first_reg = u->last_reg = rtime; 997 bch_uuid_write(c); 998 999 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1000 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1001 1002 bch_write_bdev_super(dc, &cl); 1003 closure_sync(&cl); 1004 } else { 1005 u->last_reg = rtime; 1006 bch_uuid_write(c); 1007 } 1008 1009 bcache_device_attach(&dc->disk, c, u - c->uuids); 1010 list_move(&dc->list, &c->cached_devs); 1011 calc_cached_dev_sectors(c); 1012 1013 smp_wmb(); 1014 /* 1015 * dc->c must be set before dc->count != 0 - paired with the mb in 1016 * cached_dev_get() 1017 */ 1018 atomic_set(&dc->count, 1); 1019 1020 /* Block writeback thread, but spawn it */ 1021 down_write(&dc->writeback_lock); 1022 if (bch_cached_dev_writeback_start(dc)) { 1023 up_write(&dc->writeback_lock); 1024 return -ENOMEM; 1025 } 1026 1027 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1028 bch_sectors_dirty_init(dc); 1029 atomic_set(&dc->has_dirty, 1); 1030 atomic_inc(&dc->count); 1031 bch_writeback_queue(dc); 1032 } 1033 1034 bch_cached_dev_run(dc); 1035 bcache_device_link(&dc->disk, c, "bdev"); 1036 1037 /* Allow the writeback thread to proceed */ 1038 up_write(&dc->writeback_lock); 1039 1040 pr_info("Caching %s as %s on set %pU", 1041 bdevname(dc->bdev, buf), dc->disk.disk->disk_name, 1042 dc->disk.c->sb.set_uuid); 1043 return 0; 1044 } 1045 1046 void bch_cached_dev_release(struct kobject *kobj) 1047 { 1048 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1049 disk.kobj); 1050 kfree(dc); 1051 module_put(THIS_MODULE); 1052 } 1053 1054 static void cached_dev_free(struct closure *cl) 1055 { 1056 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1057 1058 cancel_delayed_work_sync(&dc->writeback_rate_update); 1059 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1060 kthread_stop(dc->writeback_thread); 1061 1062 mutex_lock(&bch_register_lock); 1063 1064 if (atomic_read(&dc->running)) 1065 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1066 bcache_device_free(&dc->disk); 1067 list_del(&dc->list); 1068 1069 mutex_unlock(&bch_register_lock); 1070 1071 if (!IS_ERR_OR_NULL(dc->bdev)) 1072 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1073 1074 wake_up(&unregister_wait); 1075 1076 kobject_put(&dc->disk.kobj); 1077 } 1078 1079 static void cached_dev_flush(struct closure *cl) 1080 { 1081 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1082 struct bcache_device *d = &dc->disk; 1083 1084 mutex_lock(&bch_register_lock); 1085 bcache_device_unlink(d); 1086 mutex_unlock(&bch_register_lock); 1087 1088 bch_cache_accounting_destroy(&dc->accounting); 1089 kobject_del(&d->kobj); 1090 1091 continue_at(cl, cached_dev_free, system_wq); 1092 } 1093 1094 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1095 { 1096 int ret; 1097 struct io *io; 1098 struct request_queue *q = bdev_get_queue(dc->bdev); 1099 1100 __module_get(THIS_MODULE); 1101 INIT_LIST_HEAD(&dc->list); 1102 closure_init(&dc->disk.cl, NULL); 1103 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1104 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1105 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1106 sema_init(&dc->sb_write_mutex, 1); 1107 INIT_LIST_HEAD(&dc->io_lru); 1108 spin_lock_init(&dc->io_lock); 1109 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1110 1111 dc->sequential_cutoff = 4 << 20; 1112 1113 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1114 list_add(&io->lru, &dc->io_lru); 1115 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1116 } 1117 1118 dc->disk.stripe_size = q->limits.io_opt >> 9; 1119 1120 if (dc->disk.stripe_size) 1121 dc->partial_stripes_expensive = 1122 q->limits.raid_partial_stripes_expensive; 1123 1124 ret = bcache_device_init(&dc->disk, block_size, 1125 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1126 if (ret) 1127 return ret; 1128 1129 set_capacity(dc->disk.disk, 1130 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1131 1132 dc->disk.disk->queue->backing_dev_info.ra_pages = 1133 max(dc->disk.disk->queue->backing_dev_info.ra_pages, 1134 q->backing_dev_info.ra_pages); 1135 1136 bch_cached_dev_request_init(dc); 1137 bch_cached_dev_writeback_init(dc); 1138 return 0; 1139 } 1140 1141 /* Cached device - bcache superblock */ 1142 1143 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1144 struct block_device *bdev, 1145 struct cached_dev *dc) 1146 { 1147 char name[BDEVNAME_SIZE]; 1148 const char *err = "cannot allocate memory"; 1149 struct cache_set *c; 1150 1151 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1152 dc->bdev = bdev; 1153 dc->bdev->bd_holder = dc; 1154 1155 bio_init(&dc->sb_bio); 1156 dc->sb_bio.bi_max_vecs = 1; 1157 dc->sb_bio.bi_io_vec = dc->sb_bio.bi_inline_vecs; 1158 dc->sb_bio.bi_io_vec[0].bv_page = sb_page; 1159 get_page(sb_page); 1160 1161 if (cached_dev_init(dc, sb->block_size << 9)) 1162 goto err; 1163 1164 err = "error creating kobject"; 1165 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1166 "bcache")) 1167 goto err; 1168 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1169 goto err; 1170 1171 pr_info("registered backing device %s", bdevname(bdev, name)); 1172 1173 list_add(&dc->list, &uncached_devices); 1174 list_for_each_entry(c, &bch_cache_sets, list) 1175 bch_cached_dev_attach(dc, c); 1176 1177 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1178 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1179 bch_cached_dev_run(dc); 1180 1181 return; 1182 err: 1183 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1184 bcache_device_stop(&dc->disk); 1185 } 1186 1187 /* Flash only volumes */ 1188 1189 void bch_flash_dev_release(struct kobject *kobj) 1190 { 1191 struct bcache_device *d = container_of(kobj, struct bcache_device, 1192 kobj); 1193 kfree(d); 1194 } 1195 1196 static void flash_dev_free(struct closure *cl) 1197 { 1198 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1199 mutex_lock(&bch_register_lock); 1200 bcache_device_free(d); 1201 mutex_unlock(&bch_register_lock); 1202 kobject_put(&d->kobj); 1203 } 1204 1205 static void flash_dev_flush(struct closure *cl) 1206 { 1207 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1208 1209 mutex_lock(&bch_register_lock); 1210 bcache_device_unlink(d); 1211 mutex_unlock(&bch_register_lock); 1212 kobject_del(&d->kobj); 1213 continue_at(cl, flash_dev_free, system_wq); 1214 } 1215 1216 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1217 { 1218 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1219 GFP_KERNEL); 1220 if (!d) 1221 return -ENOMEM; 1222 1223 closure_init(&d->cl, NULL); 1224 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1225 1226 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1227 1228 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1229 goto err; 1230 1231 bcache_device_attach(d, c, u - c->uuids); 1232 bch_flash_dev_request_init(d); 1233 add_disk(d->disk); 1234 1235 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1236 goto err; 1237 1238 bcache_device_link(d, c, "volume"); 1239 1240 return 0; 1241 err: 1242 kobject_put(&d->kobj); 1243 return -ENOMEM; 1244 } 1245 1246 static int flash_devs_run(struct cache_set *c) 1247 { 1248 int ret = 0; 1249 struct uuid_entry *u; 1250 1251 for (u = c->uuids; 1252 u < c->uuids + c->nr_uuids && !ret; 1253 u++) 1254 if (UUID_FLASH_ONLY(u)) 1255 ret = flash_dev_run(c, u); 1256 1257 return ret; 1258 } 1259 1260 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1261 { 1262 struct uuid_entry *u; 1263 1264 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1265 return -EINTR; 1266 1267 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1268 return -EPERM; 1269 1270 u = uuid_find_empty(c); 1271 if (!u) { 1272 pr_err("Can't create volume, no room for UUID"); 1273 return -EINVAL; 1274 } 1275 1276 get_random_bytes(u->uuid, 16); 1277 memset(u->label, 0, 32); 1278 u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); 1279 1280 SET_UUID_FLASH_ONLY(u, 1); 1281 u->sectors = size >> 9; 1282 1283 bch_uuid_write(c); 1284 1285 return flash_dev_run(c, u); 1286 } 1287 1288 /* Cache set */ 1289 1290 __printf(2, 3) 1291 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1292 { 1293 va_list args; 1294 1295 if (c->on_error != ON_ERROR_PANIC && 1296 test_bit(CACHE_SET_STOPPING, &c->flags)) 1297 return false; 1298 1299 /* XXX: we can be called from atomic context 1300 acquire_console_sem(); 1301 */ 1302 1303 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1304 1305 va_start(args, fmt); 1306 vprintk(fmt, args); 1307 va_end(args); 1308 1309 printk(", disabling caching\n"); 1310 1311 if (c->on_error == ON_ERROR_PANIC) 1312 panic("panic forced after error\n"); 1313 1314 bch_cache_set_unregister(c); 1315 return true; 1316 } 1317 1318 void bch_cache_set_release(struct kobject *kobj) 1319 { 1320 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1321 kfree(c); 1322 module_put(THIS_MODULE); 1323 } 1324 1325 static void cache_set_free(struct closure *cl) 1326 { 1327 struct cache_set *c = container_of(cl, struct cache_set, cl); 1328 struct cache *ca; 1329 unsigned i; 1330 1331 if (!IS_ERR_OR_NULL(c->debug)) 1332 debugfs_remove(c->debug); 1333 1334 bch_open_buckets_free(c); 1335 bch_btree_cache_free(c); 1336 bch_journal_free(c); 1337 1338 for_each_cache(ca, c, i) 1339 if (ca) { 1340 ca->set = NULL; 1341 c->cache[ca->sb.nr_this_dev] = NULL; 1342 kobject_put(&ca->kobj); 1343 } 1344 1345 bch_bset_sort_state_free(&c->sort); 1346 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1347 1348 if (c->moving_gc_wq) 1349 destroy_workqueue(c->moving_gc_wq); 1350 if (c->bio_split) 1351 bioset_free(c->bio_split); 1352 if (c->fill_iter) 1353 mempool_destroy(c->fill_iter); 1354 if (c->bio_meta) 1355 mempool_destroy(c->bio_meta); 1356 if (c->search) 1357 mempool_destroy(c->search); 1358 kfree(c->devices); 1359 1360 mutex_lock(&bch_register_lock); 1361 list_del(&c->list); 1362 mutex_unlock(&bch_register_lock); 1363 1364 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1365 wake_up(&unregister_wait); 1366 1367 closure_debug_destroy(&c->cl); 1368 kobject_put(&c->kobj); 1369 } 1370 1371 static void cache_set_flush(struct closure *cl) 1372 { 1373 struct cache_set *c = container_of(cl, struct cache_set, caching); 1374 struct cache *ca; 1375 struct btree *b; 1376 unsigned i; 1377 1378 if (!c) 1379 closure_return(cl); 1380 1381 bch_cache_accounting_destroy(&c->accounting); 1382 1383 kobject_put(&c->internal); 1384 kobject_del(&c->kobj); 1385 1386 if (c->gc_thread) 1387 kthread_stop(c->gc_thread); 1388 1389 if (!IS_ERR_OR_NULL(c->root)) 1390 list_add(&c->root->list, &c->btree_cache); 1391 1392 /* Should skip this if we're unregistering because of an error */ 1393 list_for_each_entry(b, &c->btree_cache, list) { 1394 mutex_lock(&b->write_lock); 1395 if (btree_node_dirty(b)) 1396 __bch_btree_node_write(b, NULL); 1397 mutex_unlock(&b->write_lock); 1398 } 1399 1400 for_each_cache(ca, c, i) 1401 if (ca->alloc_thread) 1402 kthread_stop(ca->alloc_thread); 1403 1404 if (c->journal.cur) { 1405 cancel_delayed_work_sync(&c->journal.work); 1406 /* flush last journal entry if needed */ 1407 c->journal.work.work.func(&c->journal.work.work); 1408 } 1409 1410 closure_return(cl); 1411 } 1412 1413 static void __cache_set_unregister(struct closure *cl) 1414 { 1415 struct cache_set *c = container_of(cl, struct cache_set, caching); 1416 struct cached_dev *dc; 1417 size_t i; 1418 1419 mutex_lock(&bch_register_lock); 1420 1421 for (i = 0; i < c->nr_uuids; i++) 1422 if (c->devices[i]) { 1423 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1424 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1425 dc = container_of(c->devices[i], 1426 struct cached_dev, disk); 1427 bch_cached_dev_detach(dc); 1428 } else { 1429 bcache_device_stop(c->devices[i]); 1430 } 1431 } 1432 1433 mutex_unlock(&bch_register_lock); 1434 1435 continue_at(cl, cache_set_flush, system_wq); 1436 } 1437 1438 void bch_cache_set_stop(struct cache_set *c) 1439 { 1440 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1441 closure_queue(&c->caching); 1442 } 1443 1444 void bch_cache_set_unregister(struct cache_set *c) 1445 { 1446 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1447 bch_cache_set_stop(c); 1448 } 1449 1450 #define alloc_bucket_pages(gfp, c) \ 1451 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1452 1453 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1454 { 1455 int iter_size; 1456 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1457 if (!c) 1458 return NULL; 1459 1460 __module_get(THIS_MODULE); 1461 closure_init(&c->cl, NULL); 1462 set_closure_fn(&c->cl, cache_set_free, system_wq); 1463 1464 closure_init(&c->caching, &c->cl); 1465 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1466 1467 /* Maybe create continue_at_noreturn() and use it here? */ 1468 closure_set_stopped(&c->cl); 1469 closure_put(&c->cl); 1470 1471 kobject_init(&c->kobj, &bch_cache_set_ktype); 1472 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1473 1474 bch_cache_accounting_init(&c->accounting, &c->cl); 1475 1476 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1477 c->sb.block_size = sb->block_size; 1478 c->sb.bucket_size = sb->bucket_size; 1479 c->sb.nr_in_set = sb->nr_in_set; 1480 c->sb.last_mount = sb->last_mount; 1481 c->bucket_bits = ilog2(sb->bucket_size); 1482 c->block_bits = ilog2(sb->block_size); 1483 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1484 1485 c->btree_pages = bucket_pages(c); 1486 if (c->btree_pages > BTREE_MAX_PAGES) 1487 c->btree_pages = max_t(int, c->btree_pages / 4, 1488 BTREE_MAX_PAGES); 1489 1490 sema_init(&c->sb_write_mutex, 1); 1491 mutex_init(&c->bucket_lock); 1492 init_waitqueue_head(&c->btree_cache_wait); 1493 init_waitqueue_head(&c->bucket_wait); 1494 sema_init(&c->uuid_write_mutex, 1); 1495 1496 spin_lock_init(&c->btree_gc_time.lock); 1497 spin_lock_init(&c->btree_split_time.lock); 1498 spin_lock_init(&c->btree_read_time.lock); 1499 1500 bch_moving_init_cache_set(c); 1501 1502 INIT_LIST_HEAD(&c->list); 1503 INIT_LIST_HEAD(&c->cached_devs); 1504 INIT_LIST_HEAD(&c->btree_cache); 1505 INIT_LIST_HEAD(&c->btree_cache_freeable); 1506 INIT_LIST_HEAD(&c->btree_cache_freed); 1507 INIT_LIST_HEAD(&c->data_buckets); 1508 1509 c->search = mempool_create_slab_pool(32, bch_search_cache); 1510 if (!c->search) 1511 goto err; 1512 1513 iter_size = (sb->bucket_size / sb->block_size + 1) * 1514 sizeof(struct btree_iter_set); 1515 1516 if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) || 1517 !(c->bio_meta = mempool_create_kmalloc_pool(2, 1518 sizeof(struct bbio) + sizeof(struct bio_vec) * 1519 bucket_pages(c))) || 1520 !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) || 1521 !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) || 1522 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1523 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1524 WQ_MEM_RECLAIM, 0)) || 1525 bch_journal_alloc(c) || 1526 bch_btree_cache_alloc(c) || 1527 bch_open_buckets_alloc(c) || 1528 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1529 goto err; 1530 1531 c->congested_read_threshold_us = 2000; 1532 c->congested_write_threshold_us = 20000; 1533 c->error_limit = 8 << IO_ERROR_SHIFT; 1534 1535 return c; 1536 err: 1537 bch_cache_set_unregister(c); 1538 return NULL; 1539 } 1540 1541 static void run_cache_set(struct cache_set *c) 1542 { 1543 const char *err = "cannot allocate memory"; 1544 struct cached_dev *dc, *t; 1545 struct cache *ca; 1546 struct closure cl; 1547 unsigned i; 1548 1549 closure_init_stack(&cl); 1550 1551 for_each_cache(ca, c, i) 1552 c->nbuckets += ca->sb.nbuckets; 1553 1554 if (CACHE_SYNC(&c->sb)) { 1555 LIST_HEAD(journal); 1556 struct bkey *k; 1557 struct jset *j; 1558 1559 err = "cannot allocate memory for journal"; 1560 if (bch_journal_read(c, &journal)) 1561 goto err; 1562 1563 pr_debug("btree_journal_read() done"); 1564 1565 err = "no journal entries found"; 1566 if (list_empty(&journal)) 1567 goto err; 1568 1569 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1570 1571 err = "IO error reading priorities"; 1572 for_each_cache(ca, c, i) 1573 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1574 1575 /* 1576 * If prio_read() fails it'll call cache_set_error and we'll 1577 * tear everything down right away, but if we perhaps checked 1578 * sooner we could avoid journal replay. 1579 */ 1580 1581 k = &j->btree_root; 1582 1583 err = "bad btree root"; 1584 if (__bch_btree_ptr_invalid(c, k)) 1585 goto err; 1586 1587 err = "error reading btree root"; 1588 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1589 if (IS_ERR_OR_NULL(c->root)) 1590 goto err; 1591 1592 list_del_init(&c->root->list); 1593 rw_unlock(true, c->root); 1594 1595 err = uuid_read(c, j, &cl); 1596 if (err) 1597 goto err; 1598 1599 err = "error in recovery"; 1600 if (bch_btree_check(c)) 1601 goto err; 1602 1603 bch_journal_mark(c, &journal); 1604 bch_initial_gc_finish(c); 1605 pr_debug("btree_check() done"); 1606 1607 /* 1608 * bcache_journal_next() can't happen sooner, or 1609 * btree_gc_finish() will give spurious errors about last_gc > 1610 * gc_gen - this is a hack but oh well. 1611 */ 1612 bch_journal_next(&c->journal); 1613 1614 err = "error starting allocator thread"; 1615 for_each_cache(ca, c, i) 1616 if (bch_cache_allocator_start(ca)) 1617 goto err; 1618 1619 /* 1620 * First place it's safe to allocate: btree_check() and 1621 * btree_gc_finish() have to run before we have buckets to 1622 * allocate, and bch_bucket_alloc_set() might cause a journal 1623 * entry to be written so bcache_journal_next() has to be called 1624 * first. 1625 * 1626 * If the uuids were in the old format we have to rewrite them 1627 * before the next journal entry is written: 1628 */ 1629 if (j->version < BCACHE_JSET_VERSION_UUID) 1630 __uuid_write(c); 1631 1632 bch_journal_replay(c, &journal); 1633 } else { 1634 pr_notice("invalidating existing data"); 1635 1636 for_each_cache(ca, c, i) { 1637 unsigned j; 1638 1639 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1640 2, SB_JOURNAL_BUCKETS); 1641 1642 for (j = 0; j < ca->sb.keys; j++) 1643 ca->sb.d[j] = ca->sb.first_bucket + j; 1644 } 1645 1646 bch_initial_gc_finish(c); 1647 1648 err = "error starting allocator thread"; 1649 for_each_cache(ca, c, i) 1650 if (bch_cache_allocator_start(ca)) 1651 goto err; 1652 1653 mutex_lock(&c->bucket_lock); 1654 for_each_cache(ca, c, i) 1655 bch_prio_write(ca); 1656 mutex_unlock(&c->bucket_lock); 1657 1658 err = "cannot allocate new UUID bucket"; 1659 if (__uuid_write(c)) 1660 goto err; 1661 1662 err = "cannot allocate new btree root"; 1663 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1664 if (IS_ERR_OR_NULL(c->root)) 1665 goto err; 1666 1667 mutex_lock(&c->root->write_lock); 1668 bkey_copy_key(&c->root->key, &MAX_KEY); 1669 bch_btree_node_write(c->root, &cl); 1670 mutex_unlock(&c->root->write_lock); 1671 1672 bch_btree_set_root(c->root); 1673 rw_unlock(true, c->root); 1674 1675 /* 1676 * We don't want to write the first journal entry until 1677 * everything is set up - fortunately journal entries won't be 1678 * written until the SET_CACHE_SYNC() here: 1679 */ 1680 SET_CACHE_SYNC(&c->sb, true); 1681 1682 bch_journal_next(&c->journal); 1683 bch_journal_meta(c, &cl); 1684 } 1685 1686 err = "error starting gc thread"; 1687 if (bch_gc_thread_start(c)) 1688 goto err; 1689 1690 closure_sync(&cl); 1691 c->sb.last_mount = get_seconds(); 1692 bcache_write_super(c); 1693 1694 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1695 bch_cached_dev_attach(dc, c); 1696 1697 flash_devs_run(c); 1698 1699 set_bit(CACHE_SET_RUNNING, &c->flags); 1700 return; 1701 err: 1702 closure_sync(&cl); 1703 /* XXX: test this, it's broken */ 1704 bch_cache_set_error(c, "%s", err); 1705 } 1706 1707 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1708 { 1709 return ca->sb.block_size == c->sb.block_size && 1710 ca->sb.bucket_size == c->sb.bucket_size && 1711 ca->sb.nr_in_set == c->sb.nr_in_set; 1712 } 1713 1714 static const char *register_cache_set(struct cache *ca) 1715 { 1716 char buf[12]; 1717 const char *err = "cannot allocate memory"; 1718 struct cache_set *c; 1719 1720 list_for_each_entry(c, &bch_cache_sets, list) 1721 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1722 if (c->cache[ca->sb.nr_this_dev]) 1723 return "duplicate cache set member"; 1724 1725 if (!can_attach_cache(ca, c)) 1726 return "cache sb does not match set"; 1727 1728 if (!CACHE_SYNC(&ca->sb)) 1729 SET_CACHE_SYNC(&c->sb, false); 1730 1731 goto found; 1732 } 1733 1734 c = bch_cache_set_alloc(&ca->sb); 1735 if (!c) 1736 return err; 1737 1738 err = "error creating kobject"; 1739 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1740 kobject_add(&c->internal, &c->kobj, "internal")) 1741 goto err; 1742 1743 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1744 goto err; 1745 1746 bch_debug_init_cache_set(c); 1747 1748 list_add(&c->list, &bch_cache_sets); 1749 found: 1750 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1751 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1752 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1753 goto err; 1754 1755 if (ca->sb.seq > c->sb.seq) { 1756 c->sb.version = ca->sb.version; 1757 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1758 c->sb.flags = ca->sb.flags; 1759 c->sb.seq = ca->sb.seq; 1760 pr_debug("set version = %llu", c->sb.version); 1761 } 1762 1763 kobject_get(&ca->kobj); 1764 ca->set = c; 1765 ca->set->cache[ca->sb.nr_this_dev] = ca; 1766 c->cache_by_alloc[c->caches_loaded++] = ca; 1767 1768 if (c->caches_loaded == c->sb.nr_in_set) 1769 run_cache_set(c); 1770 1771 return NULL; 1772 err: 1773 bch_cache_set_unregister(c); 1774 return err; 1775 } 1776 1777 /* Cache device */ 1778 1779 void bch_cache_release(struct kobject *kobj) 1780 { 1781 struct cache *ca = container_of(kobj, struct cache, kobj); 1782 unsigned i; 1783 1784 if (ca->set) { 1785 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 1786 ca->set->cache[ca->sb.nr_this_dev] = NULL; 1787 } 1788 1789 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 1790 kfree(ca->prio_buckets); 1791 vfree(ca->buckets); 1792 1793 free_heap(&ca->heap); 1794 free_fifo(&ca->free_inc); 1795 1796 for (i = 0; i < RESERVE_NR; i++) 1797 free_fifo(&ca->free[i]); 1798 1799 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 1800 put_page(ca->sb_bio.bi_io_vec[0].bv_page); 1801 1802 if (!IS_ERR_OR_NULL(ca->bdev)) 1803 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1804 1805 kfree(ca); 1806 module_put(THIS_MODULE); 1807 } 1808 1809 static int cache_alloc(struct cache *ca) 1810 { 1811 size_t free; 1812 struct bucket *b; 1813 1814 __module_get(THIS_MODULE); 1815 kobject_init(&ca->kobj, &bch_cache_ktype); 1816 1817 bio_init(&ca->journal.bio); 1818 ca->journal.bio.bi_max_vecs = 8; 1819 ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs; 1820 1821 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 1822 1823 if (!init_fifo(&ca->free[RESERVE_BTREE], 8, GFP_KERNEL) || 1824 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 1825 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 1826 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 1827 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 1828 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 1829 !(ca->buckets = vzalloc(sizeof(struct bucket) * 1830 ca->sb.nbuckets)) || 1831 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 1832 2, GFP_KERNEL)) || 1833 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 1834 return -ENOMEM; 1835 1836 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 1837 1838 for_each_bucket(b, ca) 1839 atomic_set(&b->pin, 0); 1840 1841 return 0; 1842 } 1843 1844 static int register_cache(struct cache_sb *sb, struct page *sb_page, 1845 struct block_device *bdev, struct cache *ca) 1846 { 1847 char name[BDEVNAME_SIZE]; 1848 const char *err = NULL; /* must be set for any error case */ 1849 int ret = 0; 1850 1851 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 1852 ca->bdev = bdev; 1853 ca->bdev->bd_holder = ca; 1854 1855 bio_init(&ca->sb_bio); 1856 ca->sb_bio.bi_max_vecs = 1; 1857 ca->sb_bio.bi_io_vec = ca->sb_bio.bi_inline_vecs; 1858 ca->sb_bio.bi_io_vec[0].bv_page = sb_page; 1859 get_page(sb_page); 1860 1861 if (blk_queue_discard(bdev_get_queue(ca->bdev))) 1862 ca->discard = CACHE_DISCARD(&ca->sb); 1863 1864 ret = cache_alloc(ca); 1865 if (ret != 0) { 1866 if (ret == -ENOMEM) 1867 err = "cache_alloc(): -ENOMEM"; 1868 else 1869 err = "cache_alloc(): unknown error"; 1870 goto err; 1871 } 1872 1873 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 1874 err = "error calling kobject_add"; 1875 ret = -ENOMEM; 1876 goto out; 1877 } 1878 1879 mutex_lock(&bch_register_lock); 1880 err = register_cache_set(ca); 1881 mutex_unlock(&bch_register_lock); 1882 1883 if (err) { 1884 ret = -ENODEV; 1885 goto out; 1886 } 1887 1888 pr_info("registered cache device %s", bdevname(bdev, name)); 1889 1890 out: 1891 kobject_put(&ca->kobj); 1892 1893 err: 1894 if (err) 1895 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1896 1897 return ret; 1898 } 1899 1900 /* Global interfaces/init */ 1901 1902 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 1903 const char *, size_t); 1904 1905 kobj_attribute_write(register, register_bcache); 1906 kobj_attribute_write(register_quiet, register_bcache); 1907 1908 static bool bch_is_open_backing(struct block_device *bdev) { 1909 struct cache_set *c, *tc; 1910 struct cached_dev *dc, *t; 1911 1912 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1913 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 1914 if (dc->bdev == bdev) 1915 return true; 1916 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1917 if (dc->bdev == bdev) 1918 return true; 1919 return false; 1920 } 1921 1922 static bool bch_is_open_cache(struct block_device *bdev) { 1923 struct cache_set *c, *tc; 1924 struct cache *ca; 1925 unsigned i; 1926 1927 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1928 for_each_cache(ca, c, i) 1929 if (ca->bdev == bdev) 1930 return true; 1931 return false; 1932 } 1933 1934 static bool bch_is_open(struct block_device *bdev) { 1935 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 1936 } 1937 1938 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 1939 const char *buffer, size_t size) 1940 { 1941 ssize_t ret = size; 1942 const char *err = "cannot allocate memory"; 1943 char *path = NULL; 1944 struct cache_sb *sb = NULL; 1945 struct block_device *bdev = NULL; 1946 struct page *sb_page = NULL; 1947 1948 if (!try_module_get(THIS_MODULE)) 1949 return -EBUSY; 1950 1951 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || 1952 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) 1953 goto err; 1954 1955 err = "failed to open device"; 1956 bdev = blkdev_get_by_path(strim(path), 1957 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 1958 sb); 1959 if (IS_ERR(bdev)) { 1960 if (bdev == ERR_PTR(-EBUSY)) { 1961 bdev = lookup_bdev(strim(path)); 1962 mutex_lock(&bch_register_lock); 1963 if (!IS_ERR(bdev) && bch_is_open(bdev)) 1964 err = "device already registered"; 1965 else 1966 err = "device busy"; 1967 mutex_unlock(&bch_register_lock); 1968 if (attr == &ksysfs_register_quiet) 1969 goto out; 1970 } 1971 goto err; 1972 } 1973 1974 err = "failed to set blocksize"; 1975 if (set_blocksize(bdev, 4096)) 1976 goto err_close; 1977 1978 err = read_super(sb, bdev, &sb_page); 1979 if (err) 1980 goto err_close; 1981 1982 if (SB_IS_BDEV(sb)) { 1983 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 1984 if (!dc) 1985 goto err_close; 1986 1987 mutex_lock(&bch_register_lock); 1988 register_bdev(sb, sb_page, bdev, dc); 1989 mutex_unlock(&bch_register_lock); 1990 } else { 1991 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 1992 if (!ca) 1993 goto err_close; 1994 1995 if (register_cache(sb, sb_page, bdev, ca) != 0) 1996 goto err_close; 1997 } 1998 out: 1999 if (sb_page) 2000 put_page(sb_page); 2001 kfree(sb); 2002 kfree(path); 2003 module_put(THIS_MODULE); 2004 return ret; 2005 2006 err_close: 2007 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2008 err: 2009 pr_info("error opening %s: %s", path, err); 2010 ret = -EINVAL; 2011 goto out; 2012 } 2013 2014 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2015 { 2016 if (code == SYS_DOWN || 2017 code == SYS_HALT || 2018 code == SYS_POWER_OFF) { 2019 DEFINE_WAIT(wait); 2020 unsigned long start = jiffies; 2021 bool stopped = false; 2022 2023 struct cache_set *c, *tc; 2024 struct cached_dev *dc, *tdc; 2025 2026 mutex_lock(&bch_register_lock); 2027 2028 if (list_empty(&bch_cache_sets) && 2029 list_empty(&uncached_devices)) 2030 goto out; 2031 2032 pr_info("Stopping all devices:"); 2033 2034 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2035 bch_cache_set_stop(c); 2036 2037 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2038 bcache_device_stop(&dc->disk); 2039 2040 /* What's a condition variable? */ 2041 while (1) { 2042 long timeout = start + 2 * HZ - jiffies; 2043 2044 stopped = list_empty(&bch_cache_sets) && 2045 list_empty(&uncached_devices); 2046 2047 if (timeout < 0 || stopped) 2048 break; 2049 2050 prepare_to_wait(&unregister_wait, &wait, 2051 TASK_UNINTERRUPTIBLE); 2052 2053 mutex_unlock(&bch_register_lock); 2054 schedule_timeout(timeout); 2055 mutex_lock(&bch_register_lock); 2056 } 2057 2058 finish_wait(&unregister_wait, &wait); 2059 2060 if (stopped) 2061 pr_info("All devices stopped"); 2062 else 2063 pr_notice("Timeout waiting for devices to be closed"); 2064 out: 2065 mutex_unlock(&bch_register_lock); 2066 } 2067 2068 return NOTIFY_DONE; 2069 } 2070 2071 static struct notifier_block reboot = { 2072 .notifier_call = bcache_reboot, 2073 .priority = INT_MAX, /* before any real devices */ 2074 }; 2075 2076 static void bcache_exit(void) 2077 { 2078 bch_debug_exit(); 2079 bch_request_exit(); 2080 if (bcache_kobj) 2081 kobject_put(bcache_kobj); 2082 if (bcache_wq) 2083 destroy_workqueue(bcache_wq); 2084 if (bcache_major) 2085 unregister_blkdev(bcache_major, "bcache"); 2086 unregister_reboot_notifier(&reboot); 2087 } 2088 2089 static int __init bcache_init(void) 2090 { 2091 static const struct attribute *files[] = { 2092 &ksysfs_register.attr, 2093 &ksysfs_register_quiet.attr, 2094 NULL 2095 }; 2096 2097 mutex_init(&bch_register_lock); 2098 init_waitqueue_head(&unregister_wait); 2099 register_reboot_notifier(&reboot); 2100 closure_debug_init(); 2101 2102 bcache_major = register_blkdev(0, "bcache"); 2103 if (bcache_major < 0) { 2104 unregister_reboot_notifier(&reboot); 2105 return bcache_major; 2106 } 2107 2108 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) || 2109 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || 2110 sysfs_create_files(bcache_kobj, files) || 2111 bch_request_init() || 2112 bch_debug_init(bcache_kobj)) 2113 goto err; 2114 2115 return 0; 2116 err: 2117 bcache_exit(); 2118 return -ENOMEM; 2119 } 2120 2121 module_exit(bcache_exit); 2122 module_init(bcache_init); 2123