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 #define BCACHE_MINORS 16 /* partition support */ 62 63 /* Superblock */ 64 65 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 66 struct page **res) 67 { 68 const char *err; 69 struct cache_sb *s; 70 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 71 unsigned i; 72 73 if (!bh) 74 return "IO error"; 75 76 s = (struct cache_sb *) bh->b_data; 77 78 sb->offset = le64_to_cpu(s->offset); 79 sb->version = le64_to_cpu(s->version); 80 81 memcpy(sb->magic, s->magic, 16); 82 memcpy(sb->uuid, s->uuid, 16); 83 memcpy(sb->set_uuid, s->set_uuid, 16); 84 memcpy(sb->label, s->label, SB_LABEL_SIZE); 85 86 sb->flags = le64_to_cpu(s->flags); 87 sb->seq = le64_to_cpu(s->seq); 88 sb->last_mount = le32_to_cpu(s->last_mount); 89 sb->first_bucket = le16_to_cpu(s->first_bucket); 90 sb->keys = le16_to_cpu(s->keys); 91 92 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 93 sb->d[i] = le64_to_cpu(s->d[i]); 94 95 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 96 sb->version, sb->flags, sb->seq, sb->keys); 97 98 err = "Not a bcache superblock"; 99 if (sb->offset != SB_SECTOR) 100 goto err; 101 102 if (memcmp(sb->magic, bcache_magic, 16)) 103 goto err; 104 105 err = "Too many journal buckets"; 106 if (sb->keys > SB_JOURNAL_BUCKETS) 107 goto err; 108 109 err = "Bad checksum"; 110 if (s->csum != csum_set(s)) 111 goto err; 112 113 err = "Bad UUID"; 114 if (bch_is_zero(sb->uuid, 16)) 115 goto err; 116 117 sb->block_size = le16_to_cpu(s->block_size); 118 119 err = "Superblock block size smaller than device block size"; 120 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 121 goto err; 122 123 switch (sb->version) { 124 case BCACHE_SB_VERSION_BDEV: 125 sb->data_offset = BDEV_DATA_START_DEFAULT; 126 break; 127 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 128 sb->data_offset = le64_to_cpu(s->data_offset); 129 130 err = "Bad data offset"; 131 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 132 goto err; 133 134 break; 135 case BCACHE_SB_VERSION_CDEV: 136 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 137 sb->nbuckets = le64_to_cpu(s->nbuckets); 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_iter.bi_size = SB_SIZE; 216 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 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(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_status, "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_status, 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, int op, unsigned long op_flags, 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_opf = REQ_SYNC | REQ_META | op_flags; 352 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 353 354 bio->bi_end_io = uuid_endio; 355 bio->bi_private = cl; 356 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 357 bch_bio_map(bio, c->uuids); 358 359 bch_submit_bbio(bio, c, k, i); 360 361 if (op != REQ_OP_WRITE) 362 break; 363 } 364 365 bch_extent_to_text(buf, sizeof(buf), k); 366 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 367 368 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 369 if (!bch_is_zero(u->uuid, 16)) 370 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 371 u - c->uuids, u->uuid, u->label, 372 u->first_reg, u->last_reg, u->invalidated); 373 374 closure_return_with_destructor(cl, uuid_io_unlock); 375 } 376 377 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 378 { 379 struct bkey *k = &j->uuid_bucket; 380 381 if (__bch_btree_ptr_invalid(c, k)) 382 return "bad uuid pointer"; 383 384 bkey_copy(&c->uuid_bucket, k); 385 uuid_io(c, REQ_OP_READ, 0, k, cl); 386 387 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 388 struct uuid_entry_v0 *u0 = (void *) c->uuids; 389 struct uuid_entry *u1 = (void *) c->uuids; 390 int i; 391 392 closure_sync(cl); 393 394 /* 395 * Since the new uuid entry is bigger than the old, we have to 396 * convert starting at the highest memory address and work down 397 * in order to do it in place 398 */ 399 400 for (i = c->nr_uuids - 1; 401 i >= 0; 402 --i) { 403 memcpy(u1[i].uuid, u0[i].uuid, 16); 404 memcpy(u1[i].label, u0[i].label, 32); 405 406 u1[i].first_reg = u0[i].first_reg; 407 u1[i].last_reg = u0[i].last_reg; 408 u1[i].invalidated = u0[i].invalidated; 409 410 u1[i].flags = 0; 411 u1[i].sectors = 0; 412 } 413 } 414 415 return NULL; 416 } 417 418 static int __uuid_write(struct cache_set *c) 419 { 420 BKEY_PADDED(key) k; 421 struct closure cl; 422 closure_init_stack(&cl); 423 424 lockdep_assert_held(&bch_register_lock); 425 426 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 427 return 1; 428 429 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 430 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 431 closure_sync(&cl); 432 433 bkey_copy(&c->uuid_bucket, &k.key); 434 bkey_put(c, &k.key); 435 return 0; 436 } 437 438 int bch_uuid_write(struct cache_set *c) 439 { 440 int ret = __uuid_write(c); 441 442 if (!ret) 443 bch_journal_meta(c, NULL); 444 445 return ret; 446 } 447 448 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 449 { 450 struct uuid_entry *u; 451 452 for (u = c->uuids; 453 u < c->uuids + c->nr_uuids; u++) 454 if (!memcmp(u->uuid, uuid, 16)) 455 return u; 456 457 return NULL; 458 } 459 460 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 461 { 462 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 463 return uuid_find(c, zero_uuid); 464 } 465 466 /* 467 * Bucket priorities/gens: 468 * 469 * For each bucket, we store on disk its 470 * 8 bit gen 471 * 16 bit priority 472 * 473 * See alloc.c for an explanation of the gen. The priority is used to implement 474 * lru (and in the future other) cache replacement policies; for most purposes 475 * it's just an opaque integer. 476 * 477 * The gens and the priorities don't have a whole lot to do with each other, and 478 * it's actually the gens that must be written out at specific times - it's no 479 * big deal if the priorities don't get written, if we lose them we just reuse 480 * buckets in suboptimal order. 481 * 482 * On disk they're stored in a packed array, and in as many buckets are required 483 * to fit them all. The buckets we use to store them form a list; the journal 484 * header points to the first bucket, the first bucket points to the second 485 * bucket, et cetera. 486 * 487 * This code is used by the allocation code; periodically (whenever it runs out 488 * of buckets to allocate from) the allocation code will invalidate some 489 * buckets, but it can't use those buckets until their new gens are safely on 490 * disk. 491 */ 492 493 static void prio_endio(struct bio *bio) 494 { 495 struct cache *ca = bio->bi_private; 496 497 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 498 bch_bbio_free(bio, ca->set); 499 closure_put(&ca->prio); 500 } 501 502 static void prio_io(struct cache *ca, uint64_t bucket, int op, 503 unsigned long op_flags) 504 { 505 struct closure *cl = &ca->prio; 506 struct bio *bio = bch_bbio_alloc(ca->set); 507 508 closure_init_stack(cl); 509 510 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 511 bio->bi_bdev = ca->bdev; 512 bio->bi_iter.bi_size = bucket_bytes(ca); 513 514 bio->bi_end_io = prio_endio; 515 bio->bi_private = ca; 516 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 517 bch_bio_map(bio, ca->disk_buckets); 518 519 closure_bio_submit(bio, &ca->prio); 520 closure_sync(cl); 521 } 522 523 void bch_prio_write(struct cache *ca) 524 { 525 int i; 526 struct bucket *b; 527 struct closure cl; 528 529 closure_init_stack(&cl); 530 531 lockdep_assert_held(&ca->set->bucket_lock); 532 533 ca->disk_buckets->seq++; 534 535 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 536 &ca->meta_sectors_written); 537 538 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 539 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 540 541 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 542 long bucket; 543 struct prio_set *p = ca->disk_buckets; 544 struct bucket_disk *d = p->data; 545 struct bucket_disk *end = d + prios_per_bucket(ca); 546 547 for (b = ca->buckets + i * prios_per_bucket(ca); 548 b < ca->buckets + ca->sb.nbuckets && d < end; 549 b++, d++) { 550 d->prio = cpu_to_le16(b->prio); 551 d->gen = b->gen; 552 } 553 554 p->next_bucket = ca->prio_buckets[i + 1]; 555 p->magic = pset_magic(&ca->sb); 556 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 557 558 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 559 BUG_ON(bucket == -1); 560 561 mutex_unlock(&ca->set->bucket_lock); 562 prio_io(ca, bucket, REQ_OP_WRITE, 0); 563 mutex_lock(&ca->set->bucket_lock); 564 565 ca->prio_buckets[i] = bucket; 566 atomic_dec_bug(&ca->buckets[bucket].pin); 567 } 568 569 mutex_unlock(&ca->set->bucket_lock); 570 571 bch_journal_meta(ca->set, &cl); 572 closure_sync(&cl); 573 574 mutex_lock(&ca->set->bucket_lock); 575 576 /* 577 * Don't want the old priorities to get garbage collected until after we 578 * finish writing the new ones, and they're journalled 579 */ 580 for (i = 0; i < prio_buckets(ca); i++) { 581 if (ca->prio_last_buckets[i]) 582 __bch_bucket_free(ca, 583 &ca->buckets[ca->prio_last_buckets[i]]); 584 585 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 586 } 587 } 588 589 static void prio_read(struct cache *ca, uint64_t bucket) 590 { 591 struct prio_set *p = ca->disk_buckets; 592 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 593 struct bucket *b; 594 unsigned bucket_nr = 0; 595 596 for (b = ca->buckets; 597 b < ca->buckets + ca->sb.nbuckets; 598 b++, d++) { 599 if (d == end) { 600 ca->prio_buckets[bucket_nr] = bucket; 601 ca->prio_last_buckets[bucket_nr] = bucket; 602 bucket_nr++; 603 604 prio_io(ca, bucket, REQ_OP_READ, 0); 605 606 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 607 pr_warn("bad csum reading priorities"); 608 609 if (p->magic != pset_magic(&ca->sb)) 610 pr_warn("bad magic reading priorities"); 611 612 bucket = p->next_bucket; 613 d = p->data; 614 } 615 616 b->prio = le16_to_cpu(d->prio); 617 b->gen = b->last_gc = d->gen; 618 } 619 } 620 621 /* Bcache device */ 622 623 static int open_dev(struct block_device *b, fmode_t mode) 624 { 625 struct bcache_device *d = b->bd_disk->private_data; 626 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 627 return -ENXIO; 628 629 closure_get(&d->cl); 630 return 0; 631 } 632 633 static void release_dev(struct gendisk *b, fmode_t mode) 634 { 635 struct bcache_device *d = b->private_data; 636 closure_put(&d->cl); 637 } 638 639 static int ioctl_dev(struct block_device *b, fmode_t mode, 640 unsigned int cmd, unsigned long arg) 641 { 642 struct bcache_device *d = b->bd_disk->private_data; 643 return d->ioctl(d, mode, cmd, arg); 644 } 645 646 static const struct block_device_operations bcache_ops = { 647 .open = open_dev, 648 .release = release_dev, 649 .ioctl = ioctl_dev, 650 .owner = THIS_MODULE, 651 }; 652 653 void bcache_device_stop(struct bcache_device *d) 654 { 655 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 656 closure_queue(&d->cl); 657 } 658 659 static void bcache_device_unlink(struct bcache_device *d) 660 { 661 lockdep_assert_held(&bch_register_lock); 662 663 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 664 unsigned i; 665 struct cache *ca; 666 667 sysfs_remove_link(&d->c->kobj, d->name); 668 sysfs_remove_link(&d->kobj, "cache"); 669 670 for_each_cache(ca, d->c, i) 671 bd_unlink_disk_holder(ca->bdev, d->disk); 672 } 673 } 674 675 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 676 const char *name) 677 { 678 unsigned i; 679 struct cache *ca; 680 681 for_each_cache(ca, d->c, i) 682 bd_link_disk_holder(ca->bdev, d->disk); 683 684 snprintf(d->name, BCACHEDEVNAME_SIZE, 685 "%s%u", name, d->id); 686 687 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 688 sysfs_create_link(&c->kobj, &d->kobj, d->name), 689 "Couldn't create device <-> cache set symlinks"); 690 691 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 692 } 693 694 static void bcache_device_detach(struct bcache_device *d) 695 { 696 lockdep_assert_held(&bch_register_lock); 697 698 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 699 struct uuid_entry *u = d->c->uuids + d->id; 700 701 SET_UUID_FLASH_ONLY(u, 0); 702 memcpy(u->uuid, invalid_uuid, 16); 703 u->invalidated = cpu_to_le32(get_seconds()); 704 bch_uuid_write(d->c); 705 } 706 707 bcache_device_unlink(d); 708 709 d->c->devices[d->id] = NULL; 710 closure_put(&d->c->caching); 711 d->c = NULL; 712 } 713 714 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 715 unsigned id) 716 { 717 d->id = id; 718 d->c = c; 719 c->devices[id] = d; 720 721 closure_get(&c->caching); 722 } 723 724 static void bcache_device_free(struct bcache_device *d) 725 { 726 lockdep_assert_held(&bch_register_lock); 727 728 pr_info("%s stopped", d->disk->disk_name); 729 730 if (d->c) 731 bcache_device_detach(d); 732 if (d->disk && d->disk->flags & GENHD_FL_UP) 733 del_gendisk(d->disk); 734 if (d->disk && d->disk->queue) 735 blk_cleanup_queue(d->disk->queue); 736 if (d->disk) { 737 ida_simple_remove(&bcache_minor, d->disk->first_minor); 738 put_disk(d->disk); 739 } 740 741 if (d->bio_split) 742 bioset_free(d->bio_split); 743 kvfree(d->full_dirty_stripes); 744 kvfree(d->stripe_sectors_dirty); 745 746 closure_debug_destroy(&d->cl); 747 } 748 749 static int bcache_device_init(struct bcache_device *d, unsigned block_size, 750 sector_t sectors) 751 { 752 struct request_queue *q; 753 size_t n; 754 int minor; 755 756 if (!d->stripe_size) 757 d->stripe_size = 1 << 31; 758 759 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 760 761 if (!d->nr_stripes || 762 d->nr_stripes > INT_MAX || 763 d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) { 764 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 765 (unsigned)d->nr_stripes); 766 return -ENOMEM; 767 } 768 769 n = d->nr_stripes * sizeof(atomic_t); 770 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 771 if (!d->stripe_sectors_dirty) 772 return -ENOMEM; 773 774 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 775 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 776 if (!d->full_dirty_stripes) 777 return -ENOMEM; 778 779 minor = ida_simple_get(&bcache_minor, 0, MINORMASK + 1, GFP_KERNEL); 780 if (minor < 0) 781 return minor; 782 783 minor *= BCACHE_MINORS; 784 785 if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio), 786 BIOSET_NEED_BVECS | 787 BIOSET_NEED_RESCUER)) || 788 !(d->disk = alloc_disk(BCACHE_MINORS))) { 789 ida_simple_remove(&bcache_minor, minor); 790 return -ENOMEM; 791 } 792 793 set_capacity(d->disk, sectors); 794 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", minor); 795 796 d->disk->major = bcache_major; 797 d->disk->first_minor = minor; 798 d->disk->fops = &bcache_ops; 799 d->disk->private_data = d; 800 801 q = blk_alloc_queue(GFP_KERNEL); 802 if (!q) 803 return -ENOMEM; 804 805 blk_queue_make_request(q, NULL); 806 d->disk->queue = q; 807 q->queuedata = d; 808 q->backing_dev_info->congested_data = d; 809 q->limits.max_hw_sectors = UINT_MAX; 810 q->limits.max_sectors = UINT_MAX; 811 q->limits.max_segment_size = UINT_MAX; 812 q->limits.max_segments = BIO_MAX_PAGES; 813 blk_queue_max_discard_sectors(q, UINT_MAX); 814 q->limits.discard_granularity = 512; 815 q->limits.io_min = block_size; 816 q->limits.logical_block_size = block_size; 817 q->limits.physical_block_size = block_size; 818 set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags); 819 clear_bit(QUEUE_FLAG_ADD_RANDOM, &d->disk->queue->queue_flags); 820 set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags); 821 822 blk_queue_write_cache(q, true, true); 823 824 return 0; 825 } 826 827 /* Cached device */ 828 829 static void calc_cached_dev_sectors(struct cache_set *c) 830 { 831 uint64_t sectors = 0; 832 struct cached_dev *dc; 833 834 list_for_each_entry(dc, &c->cached_devs, list) 835 sectors += bdev_sectors(dc->bdev); 836 837 c->cached_dev_sectors = sectors; 838 } 839 840 void bch_cached_dev_run(struct cached_dev *dc) 841 { 842 struct bcache_device *d = &dc->disk; 843 char buf[SB_LABEL_SIZE + 1]; 844 char *env[] = { 845 "DRIVER=bcache", 846 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 847 NULL, 848 NULL, 849 }; 850 851 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 852 buf[SB_LABEL_SIZE] = '\0'; 853 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 854 855 if (atomic_xchg(&dc->running, 1)) { 856 kfree(env[1]); 857 kfree(env[2]); 858 return; 859 } 860 861 if (!d->c && 862 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 863 struct closure cl; 864 closure_init_stack(&cl); 865 866 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 867 bch_write_bdev_super(dc, &cl); 868 closure_sync(&cl); 869 } 870 871 add_disk(d->disk); 872 bd_link_disk_holder(dc->bdev, dc->disk.disk); 873 /* won't show up in the uevent file, use udevadm monitor -e instead 874 * only class / kset properties are persistent */ 875 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 876 kfree(env[1]); 877 kfree(env[2]); 878 879 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 880 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 881 pr_debug("error creating sysfs link"); 882 } 883 884 static void cached_dev_detach_finish(struct work_struct *w) 885 { 886 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 887 char buf[BDEVNAME_SIZE]; 888 struct closure cl; 889 closure_init_stack(&cl); 890 891 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 892 BUG_ON(atomic_read(&dc->count)); 893 894 mutex_lock(&bch_register_lock); 895 896 memset(&dc->sb.set_uuid, 0, 16); 897 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 898 899 bch_write_bdev_super(dc, &cl); 900 closure_sync(&cl); 901 902 bcache_device_detach(&dc->disk); 903 list_move(&dc->list, &uncached_devices); 904 905 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 906 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 907 908 mutex_unlock(&bch_register_lock); 909 910 pr_info("Caching disabled for %s", bdevname(dc->bdev, buf)); 911 912 /* Drop ref we took in cached_dev_detach() */ 913 closure_put(&dc->disk.cl); 914 } 915 916 void bch_cached_dev_detach(struct cached_dev *dc) 917 { 918 lockdep_assert_held(&bch_register_lock); 919 920 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 921 return; 922 923 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 924 return; 925 926 /* 927 * Block the device from being closed and freed until we're finished 928 * detaching 929 */ 930 closure_get(&dc->disk.cl); 931 932 bch_writeback_queue(dc); 933 cached_dev_put(dc); 934 } 935 936 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c) 937 { 938 uint32_t rtime = cpu_to_le32(get_seconds()); 939 struct uuid_entry *u; 940 char buf[BDEVNAME_SIZE]; 941 942 bdevname(dc->bdev, buf); 943 944 if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)) 945 return -ENOENT; 946 947 if (dc->disk.c) { 948 pr_err("Can't attach %s: already attached", buf); 949 return -EINVAL; 950 } 951 952 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 953 pr_err("Can't attach %s: shutting down", buf); 954 return -EINVAL; 955 } 956 957 if (dc->sb.block_size < c->sb.block_size) { 958 /* Will die */ 959 pr_err("Couldn't attach %s: block size less than set's block size", 960 buf); 961 return -EINVAL; 962 } 963 964 u = uuid_find(c, dc->sb.uuid); 965 966 if (u && 967 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 968 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 969 memcpy(u->uuid, invalid_uuid, 16); 970 u->invalidated = cpu_to_le32(get_seconds()); 971 u = NULL; 972 } 973 974 if (!u) { 975 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 976 pr_err("Couldn't find uuid for %s in set", buf); 977 return -ENOENT; 978 } 979 980 u = uuid_find_empty(c); 981 if (!u) { 982 pr_err("Not caching %s, no room for UUID", buf); 983 return -EINVAL; 984 } 985 } 986 987 /* Deadlocks since we're called via sysfs... 988 sysfs_remove_file(&dc->kobj, &sysfs_attach); 989 */ 990 991 if (bch_is_zero(u->uuid, 16)) { 992 struct closure cl; 993 closure_init_stack(&cl); 994 995 memcpy(u->uuid, dc->sb.uuid, 16); 996 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 997 u->first_reg = u->last_reg = rtime; 998 bch_uuid_write(c); 999 1000 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1001 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1002 1003 bch_write_bdev_super(dc, &cl); 1004 closure_sync(&cl); 1005 } else { 1006 u->last_reg = rtime; 1007 bch_uuid_write(c); 1008 } 1009 1010 bcache_device_attach(&dc->disk, c, u - c->uuids); 1011 list_move(&dc->list, &c->cached_devs); 1012 calc_cached_dev_sectors(c); 1013 1014 smp_wmb(); 1015 /* 1016 * dc->c must be set before dc->count != 0 - paired with the mb in 1017 * cached_dev_get() 1018 */ 1019 atomic_set(&dc->count, 1); 1020 1021 /* Block writeback thread, but spawn it */ 1022 down_write(&dc->writeback_lock); 1023 if (bch_cached_dev_writeback_start(dc)) { 1024 up_write(&dc->writeback_lock); 1025 return -ENOMEM; 1026 } 1027 1028 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1029 bch_sectors_dirty_init(dc); 1030 atomic_set(&dc->has_dirty, 1); 1031 atomic_inc(&dc->count); 1032 bch_writeback_queue(dc); 1033 } 1034 1035 bch_cached_dev_run(dc); 1036 bcache_device_link(&dc->disk, c, "bdev"); 1037 1038 /* Allow the writeback thread to proceed */ 1039 up_write(&dc->writeback_lock); 1040 1041 pr_info("Caching %s as %s on set %pU", 1042 bdevname(dc->bdev, buf), dc->disk.disk->disk_name, 1043 dc->disk.c->sb.set_uuid); 1044 return 0; 1045 } 1046 1047 void bch_cached_dev_release(struct kobject *kobj) 1048 { 1049 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1050 disk.kobj); 1051 kfree(dc); 1052 module_put(THIS_MODULE); 1053 } 1054 1055 static void cached_dev_free(struct closure *cl) 1056 { 1057 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1058 1059 cancel_delayed_work_sync(&dc->writeback_rate_update); 1060 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1061 kthread_stop(dc->writeback_thread); 1062 1063 mutex_lock(&bch_register_lock); 1064 1065 if (atomic_read(&dc->running)) 1066 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1067 bcache_device_free(&dc->disk); 1068 list_del(&dc->list); 1069 1070 mutex_unlock(&bch_register_lock); 1071 1072 if (!IS_ERR_OR_NULL(dc->bdev)) 1073 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1074 1075 wake_up(&unregister_wait); 1076 1077 kobject_put(&dc->disk.kobj); 1078 } 1079 1080 static void cached_dev_flush(struct closure *cl) 1081 { 1082 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1083 struct bcache_device *d = &dc->disk; 1084 1085 mutex_lock(&bch_register_lock); 1086 bcache_device_unlink(d); 1087 mutex_unlock(&bch_register_lock); 1088 1089 bch_cache_accounting_destroy(&dc->accounting); 1090 kobject_del(&d->kobj); 1091 1092 continue_at(cl, cached_dev_free, system_wq); 1093 } 1094 1095 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1096 { 1097 int ret; 1098 struct io *io; 1099 struct request_queue *q = bdev_get_queue(dc->bdev); 1100 1101 __module_get(THIS_MODULE); 1102 INIT_LIST_HEAD(&dc->list); 1103 closure_init(&dc->disk.cl, NULL); 1104 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1105 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1106 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1107 sema_init(&dc->sb_write_mutex, 1); 1108 INIT_LIST_HEAD(&dc->io_lru); 1109 spin_lock_init(&dc->io_lock); 1110 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1111 1112 dc->sequential_cutoff = 4 << 20; 1113 1114 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1115 list_add(&io->lru, &dc->io_lru); 1116 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1117 } 1118 1119 dc->disk.stripe_size = q->limits.io_opt >> 9; 1120 1121 if (dc->disk.stripe_size) 1122 dc->partial_stripes_expensive = 1123 q->limits.raid_partial_stripes_expensive; 1124 1125 ret = bcache_device_init(&dc->disk, block_size, 1126 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1127 if (ret) 1128 return ret; 1129 1130 set_capacity(dc->disk.disk, 1131 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1132 1133 dc->disk.disk->queue->backing_dev_info->ra_pages = 1134 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1135 q->backing_dev_info->ra_pages); 1136 1137 bch_cached_dev_request_init(dc); 1138 bch_cached_dev_writeback_init(dc); 1139 return 0; 1140 } 1141 1142 /* Cached device - bcache superblock */ 1143 1144 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1145 struct block_device *bdev, 1146 struct cached_dev *dc) 1147 { 1148 char name[BDEVNAME_SIZE]; 1149 const char *err = "cannot allocate memory"; 1150 struct cache_set *c; 1151 1152 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1153 dc->bdev = bdev; 1154 dc->bdev->bd_holder = dc; 1155 1156 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1157 dc->sb_bio.bi_io_vec[0].bv_page = sb_page; 1158 get_page(sb_page); 1159 1160 if (cached_dev_init(dc, sb->block_size << 9)) 1161 goto err; 1162 1163 err = "error creating kobject"; 1164 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1165 "bcache")) 1166 goto err; 1167 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1168 goto err; 1169 1170 pr_info("registered backing device %s", bdevname(bdev, name)); 1171 1172 list_add(&dc->list, &uncached_devices); 1173 list_for_each_entry(c, &bch_cache_sets, list) 1174 bch_cached_dev_attach(dc, c); 1175 1176 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1177 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1178 bch_cached_dev_run(dc); 1179 1180 return; 1181 err: 1182 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1183 bcache_device_stop(&dc->disk); 1184 } 1185 1186 /* Flash only volumes */ 1187 1188 void bch_flash_dev_release(struct kobject *kobj) 1189 { 1190 struct bcache_device *d = container_of(kobj, struct bcache_device, 1191 kobj); 1192 kfree(d); 1193 } 1194 1195 static void flash_dev_free(struct closure *cl) 1196 { 1197 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1198 mutex_lock(&bch_register_lock); 1199 bcache_device_free(d); 1200 mutex_unlock(&bch_register_lock); 1201 kobject_put(&d->kobj); 1202 } 1203 1204 static void flash_dev_flush(struct closure *cl) 1205 { 1206 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1207 1208 mutex_lock(&bch_register_lock); 1209 bcache_device_unlink(d); 1210 mutex_unlock(&bch_register_lock); 1211 kobject_del(&d->kobj); 1212 continue_at(cl, flash_dev_free, system_wq); 1213 } 1214 1215 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1216 { 1217 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1218 GFP_KERNEL); 1219 if (!d) 1220 return -ENOMEM; 1221 1222 closure_init(&d->cl, NULL); 1223 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1224 1225 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1226 1227 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1228 goto err; 1229 1230 bcache_device_attach(d, c, u - c->uuids); 1231 bch_flash_dev_request_init(d); 1232 add_disk(d->disk); 1233 1234 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1235 goto err; 1236 1237 bcache_device_link(d, c, "volume"); 1238 1239 return 0; 1240 err: 1241 kobject_put(&d->kobj); 1242 return -ENOMEM; 1243 } 1244 1245 static int flash_devs_run(struct cache_set *c) 1246 { 1247 int ret = 0; 1248 struct uuid_entry *u; 1249 1250 for (u = c->uuids; 1251 u < c->uuids + c->nr_uuids && !ret; 1252 u++) 1253 if (UUID_FLASH_ONLY(u)) 1254 ret = flash_dev_run(c, u); 1255 1256 return ret; 1257 } 1258 1259 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1260 { 1261 struct uuid_entry *u; 1262 1263 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1264 return -EINTR; 1265 1266 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1267 return -EPERM; 1268 1269 u = uuid_find_empty(c); 1270 if (!u) { 1271 pr_err("Can't create volume, no room for UUID"); 1272 return -EINVAL; 1273 } 1274 1275 get_random_bytes(u->uuid, 16); 1276 memset(u->label, 0, 32); 1277 u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); 1278 1279 SET_UUID_FLASH_ONLY(u, 1); 1280 u->sectors = size >> 9; 1281 1282 bch_uuid_write(c); 1283 1284 return flash_dev_run(c, u); 1285 } 1286 1287 /* Cache set */ 1288 1289 __printf(2, 3) 1290 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1291 { 1292 va_list args; 1293 1294 if (c->on_error != ON_ERROR_PANIC && 1295 test_bit(CACHE_SET_STOPPING, &c->flags)) 1296 return false; 1297 1298 /* XXX: we can be called from atomic context 1299 acquire_console_sem(); 1300 */ 1301 1302 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1303 1304 va_start(args, fmt); 1305 vprintk(fmt, args); 1306 va_end(args); 1307 1308 printk(", disabling caching\n"); 1309 1310 if (c->on_error == ON_ERROR_PANIC) 1311 panic("panic forced after error\n"); 1312 1313 bch_cache_set_unregister(c); 1314 return true; 1315 } 1316 1317 void bch_cache_set_release(struct kobject *kobj) 1318 { 1319 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1320 kfree(c); 1321 module_put(THIS_MODULE); 1322 } 1323 1324 static void cache_set_free(struct closure *cl) 1325 { 1326 struct cache_set *c = container_of(cl, struct cache_set, cl); 1327 struct cache *ca; 1328 unsigned i; 1329 1330 if (!IS_ERR_OR_NULL(c->debug)) 1331 debugfs_remove(c->debug); 1332 1333 bch_open_buckets_free(c); 1334 bch_btree_cache_free(c); 1335 bch_journal_free(c); 1336 1337 for_each_cache(ca, c, i) 1338 if (ca) { 1339 ca->set = NULL; 1340 c->cache[ca->sb.nr_this_dev] = NULL; 1341 kobject_put(&ca->kobj); 1342 } 1343 1344 bch_bset_sort_state_free(&c->sort); 1345 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1346 1347 if (c->moving_gc_wq) 1348 destroy_workqueue(c->moving_gc_wq); 1349 if (c->bio_split) 1350 bioset_free(c->bio_split); 1351 if (c->fill_iter) 1352 mempool_destroy(c->fill_iter); 1353 if (c->bio_meta) 1354 mempool_destroy(c->bio_meta); 1355 if (c->search) 1356 mempool_destroy(c->search); 1357 kfree(c->devices); 1358 1359 mutex_lock(&bch_register_lock); 1360 list_del(&c->list); 1361 mutex_unlock(&bch_register_lock); 1362 1363 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1364 wake_up(&unregister_wait); 1365 1366 closure_debug_destroy(&c->cl); 1367 kobject_put(&c->kobj); 1368 } 1369 1370 static void cache_set_flush(struct closure *cl) 1371 { 1372 struct cache_set *c = container_of(cl, struct cache_set, caching); 1373 struct cache *ca; 1374 struct btree *b; 1375 unsigned i; 1376 1377 if (!c) 1378 closure_return(cl); 1379 1380 bch_cache_accounting_destroy(&c->accounting); 1381 1382 kobject_put(&c->internal); 1383 kobject_del(&c->kobj); 1384 1385 if (c->gc_thread) 1386 kthread_stop(c->gc_thread); 1387 1388 if (!IS_ERR_OR_NULL(c->root)) 1389 list_add(&c->root->list, &c->btree_cache); 1390 1391 /* Should skip this if we're unregistering because of an error */ 1392 list_for_each_entry(b, &c->btree_cache, list) { 1393 mutex_lock(&b->write_lock); 1394 if (btree_node_dirty(b)) 1395 __bch_btree_node_write(b, NULL); 1396 mutex_unlock(&b->write_lock); 1397 } 1398 1399 for_each_cache(ca, c, i) 1400 if (ca->alloc_thread) 1401 kthread_stop(ca->alloc_thread); 1402 1403 if (c->journal.cur) { 1404 cancel_delayed_work_sync(&c->journal.work); 1405 /* flush last journal entry if needed */ 1406 c->journal.work.work.func(&c->journal.work.work); 1407 } 1408 1409 closure_return(cl); 1410 } 1411 1412 static void __cache_set_unregister(struct closure *cl) 1413 { 1414 struct cache_set *c = container_of(cl, struct cache_set, caching); 1415 struct cached_dev *dc; 1416 size_t i; 1417 1418 mutex_lock(&bch_register_lock); 1419 1420 for (i = 0; i < c->nr_uuids; i++) 1421 if (c->devices[i]) { 1422 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1423 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1424 dc = container_of(c->devices[i], 1425 struct cached_dev, disk); 1426 bch_cached_dev_detach(dc); 1427 } else { 1428 bcache_device_stop(c->devices[i]); 1429 } 1430 } 1431 1432 mutex_unlock(&bch_register_lock); 1433 1434 continue_at(cl, cache_set_flush, system_wq); 1435 } 1436 1437 void bch_cache_set_stop(struct cache_set *c) 1438 { 1439 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1440 closure_queue(&c->caching); 1441 } 1442 1443 void bch_cache_set_unregister(struct cache_set *c) 1444 { 1445 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1446 bch_cache_set_stop(c); 1447 } 1448 1449 #define alloc_bucket_pages(gfp, c) \ 1450 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1451 1452 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1453 { 1454 int iter_size; 1455 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1456 if (!c) 1457 return NULL; 1458 1459 __module_get(THIS_MODULE); 1460 closure_init(&c->cl, NULL); 1461 set_closure_fn(&c->cl, cache_set_free, system_wq); 1462 1463 closure_init(&c->caching, &c->cl); 1464 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1465 1466 /* Maybe create continue_at_noreturn() and use it here? */ 1467 closure_set_stopped(&c->cl); 1468 closure_put(&c->cl); 1469 1470 kobject_init(&c->kobj, &bch_cache_set_ktype); 1471 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1472 1473 bch_cache_accounting_init(&c->accounting, &c->cl); 1474 1475 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1476 c->sb.block_size = sb->block_size; 1477 c->sb.bucket_size = sb->bucket_size; 1478 c->sb.nr_in_set = sb->nr_in_set; 1479 c->sb.last_mount = sb->last_mount; 1480 c->bucket_bits = ilog2(sb->bucket_size); 1481 c->block_bits = ilog2(sb->block_size); 1482 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1483 1484 c->btree_pages = bucket_pages(c); 1485 if (c->btree_pages > BTREE_MAX_PAGES) 1486 c->btree_pages = max_t(int, c->btree_pages / 4, 1487 BTREE_MAX_PAGES); 1488 1489 sema_init(&c->sb_write_mutex, 1); 1490 mutex_init(&c->bucket_lock); 1491 init_waitqueue_head(&c->btree_cache_wait); 1492 init_waitqueue_head(&c->bucket_wait); 1493 init_waitqueue_head(&c->gc_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 BIOSET_NEED_BVECS | 1523 BIOSET_NEED_RESCUER)) || 1524 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1525 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1526 WQ_MEM_RECLAIM, 0)) || 1527 bch_journal_alloc(c) || 1528 bch_btree_cache_alloc(c) || 1529 bch_open_buckets_alloc(c) || 1530 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1531 goto err; 1532 1533 c->congested_read_threshold_us = 2000; 1534 c->congested_write_threshold_us = 20000; 1535 c->error_limit = 8 << IO_ERROR_SHIFT; 1536 1537 return c; 1538 err: 1539 bch_cache_set_unregister(c); 1540 return NULL; 1541 } 1542 1543 static void run_cache_set(struct cache_set *c) 1544 { 1545 const char *err = "cannot allocate memory"; 1546 struct cached_dev *dc, *t; 1547 struct cache *ca; 1548 struct closure cl; 1549 unsigned i; 1550 1551 closure_init_stack(&cl); 1552 1553 for_each_cache(ca, c, i) 1554 c->nbuckets += ca->sb.nbuckets; 1555 set_gc_sectors(c); 1556 1557 if (CACHE_SYNC(&c->sb)) { 1558 LIST_HEAD(journal); 1559 struct bkey *k; 1560 struct jset *j; 1561 1562 err = "cannot allocate memory for journal"; 1563 if (bch_journal_read(c, &journal)) 1564 goto err; 1565 1566 pr_debug("btree_journal_read() done"); 1567 1568 err = "no journal entries found"; 1569 if (list_empty(&journal)) 1570 goto err; 1571 1572 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1573 1574 err = "IO error reading priorities"; 1575 for_each_cache(ca, c, i) 1576 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1577 1578 /* 1579 * If prio_read() fails it'll call cache_set_error and we'll 1580 * tear everything down right away, but if we perhaps checked 1581 * sooner we could avoid journal replay. 1582 */ 1583 1584 k = &j->btree_root; 1585 1586 err = "bad btree root"; 1587 if (__bch_btree_ptr_invalid(c, k)) 1588 goto err; 1589 1590 err = "error reading btree root"; 1591 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1592 if (IS_ERR_OR_NULL(c->root)) 1593 goto err; 1594 1595 list_del_init(&c->root->list); 1596 rw_unlock(true, c->root); 1597 1598 err = uuid_read(c, j, &cl); 1599 if (err) 1600 goto err; 1601 1602 err = "error in recovery"; 1603 if (bch_btree_check(c)) 1604 goto err; 1605 1606 bch_journal_mark(c, &journal); 1607 bch_initial_gc_finish(c); 1608 pr_debug("btree_check() done"); 1609 1610 /* 1611 * bcache_journal_next() can't happen sooner, or 1612 * btree_gc_finish() will give spurious errors about last_gc > 1613 * gc_gen - this is a hack but oh well. 1614 */ 1615 bch_journal_next(&c->journal); 1616 1617 err = "error starting allocator thread"; 1618 for_each_cache(ca, c, i) 1619 if (bch_cache_allocator_start(ca)) 1620 goto err; 1621 1622 /* 1623 * First place it's safe to allocate: btree_check() and 1624 * btree_gc_finish() have to run before we have buckets to 1625 * allocate, and bch_bucket_alloc_set() might cause a journal 1626 * entry to be written so bcache_journal_next() has to be called 1627 * first. 1628 * 1629 * If the uuids were in the old format we have to rewrite them 1630 * before the next journal entry is written: 1631 */ 1632 if (j->version < BCACHE_JSET_VERSION_UUID) 1633 __uuid_write(c); 1634 1635 bch_journal_replay(c, &journal); 1636 } else { 1637 pr_notice("invalidating existing data"); 1638 1639 for_each_cache(ca, c, i) { 1640 unsigned j; 1641 1642 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1643 2, SB_JOURNAL_BUCKETS); 1644 1645 for (j = 0; j < ca->sb.keys; j++) 1646 ca->sb.d[j] = ca->sb.first_bucket + j; 1647 } 1648 1649 bch_initial_gc_finish(c); 1650 1651 err = "error starting allocator thread"; 1652 for_each_cache(ca, c, i) 1653 if (bch_cache_allocator_start(ca)) 1654 goto err; 1655 1656 mutex_lock(&c->bucket_lock); 1657 for_each_cache(ca, c, i) 1658 bch_prio_write(ca); 1659 mutex_unlock(&c->bucket_lock); 1660 1661 err = "cannot allocate new UUID bucket"; 1662 if (__uuid_write(c)) 1663 goto err; 1664 1665 err = "cannot allocate new btree root"; 1666 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1667 if (IS_ERR_OR_NULL(c->root)) 1668 goto err; 1669 1670 mutex_lock(&c->root->write_lock); 1671 bkey_copy_key(&c->root->key, &MAX_KEY); 1672 bch_btree_node_write(c->root, &cl); 1673 mutex_unlock(&c->root->write_lock); 1674 1675 bch_btree_set_root(c->root); 1676 rw_unlock(true, c->root); 1677 1678 /* 1679 * We don't want to write the first journal entry until 1680 * everything is set up - fortunately journal entries won't be 1681 * written until the SET_CACHE_SYNC() here: 1682 */ 1683 SET_CACHE_SYNC(&c->sb, true); 1684 1685 bch_journal_next(&c->journal); 1686 bch_journal_meta(c, &cl); 1687 } 1688 1689 err = "error starting gc thread"; 1690 if (bch_gc_thread_start(c)) 1691 goto err; 1692 1693 closure_sync(&cl); 1694 c->sb.last_mount = get_seconds(); 1695 bcache_write_super(c); 1696 1697 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1698 bch_cached_dev_attach(dc, c); 1699 1700 flash_devs_run(c); 1701 1702 set_bit(CACHE_SET_RUNNING, &c->flags); 1703 return; 1704 err: 1705 closure_sync(&cl); 1706 /* XXX: test this, it's broken */ 1707 bch_cache_set_error(c, "%s", err); 1708 } 1709 1710 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1711 { 1712 return ca->sb.block_size == c->sb.block_size && 1713 ca->sb.bucket_size == c->sb.bucket_size && 1714 ca->sb.nr_in_set == c->sb.nr_in_set; 1715 } 1716 1717 static const char *register_cache_set(struct cache *ca) 1718 { 1719 char buf[12]; 1720 const char *err = "cannot allocate memory"; 1721 struct cache_set *c; 1722 1723 list_for_each_entry(c, &bch_cache_sets, list) 1724 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1725 if (c->cache[ca->sb.nr_this_dev]) 1726 return "duplicate cache set member"; 1727 1728 if (!can_attach_cache(ca, c)) 1729 return "cache sb does not match set"; 1730 1731 if (!CACHE_SYNC(&ca->sb)) 1732 SET_CACHE_SYNC(&c->sb, false); 1733 1734 goto found; 1735 } 1736 1737 c = bch_cache_set_alloc(&ca->sb); 1738 if (!c) 1739 return err; 1740 1741 err = "error creating kobject"; 1742 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1743 kobject_add(&c->internal, &c->kobj, "internal")) 1744 goto err; 1745 1746 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1747 goto err; 1748 1749 bch_debug_init_cache_set(c); 1750 1751 list_add(&c->list, &bch_cache_sets); 1752 found: 1753 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1754 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1755 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1756 goto err; 1757 1758 if (ca->sb.seq > c->sb.seq) { 1759 c->sb.version = ca->sb.version; 1760 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1761 c->sb.flags = ca->sb.flags; 1762 c->sb.seq = ca->sb.seq; 1763 pr_debug("set version = %llu", c->sb.version); 1764 } 1765 1766 kobject_get(&ca->kobj); 1767 ca->set = c; 1768 ca->set->cache[ca->sb.nr_this_dev] = ca; 1769 c->cache_by_alloc[c->caches_loaded++] = ca; 1770 1771 if (c->caches_loaded == c->sb.nr_in_set) 1772 run_cache_set(c); 1773 1774 return NULL; 1775 err: 1776 bch_cache_set_unregister(c); 1777 return err; 1778 } 1779 1780 /* Cache device */ 1781 1782 void bch_cache_release(struct kobject *kobj) 1783 { 1784 struct cache *ca = container_of(kobj, struct cache, kobj); 1785 unsigned i; 1786 1787 if (ca->set) { 1788 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 1789 ca->set->cache[ca->sb.nr_this_dev] = NULL; 1790 } 1791 1792 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 1793 kfree(ca->prio_buckets); 1794 vfree(ca->buckets); 1795 1796 free_heap(&ca->heap); 1797 free_fifo(&ca->free_inc); 1798 1799 for (i = 0; i < RESERVE_NR; i++) 1800 free_fifo(&ca->free[i]); 1801 1802 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 1803 put_page(ca->sb_bio.bi_io_vec[0].bv_page); 1804 1805 if (!IS_ERR_OR_NULL(ca->bdev)) 1806 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1807 1808 kfree(ca); 1809 module_put(THIS_MODULE); 1810 } 1811 1812 static int cache_alloc(struct cache *ca) 1813 { 1814 size_t free; 1815 struct bucket *b; 1816 1817 __module_get(THIS_MODULE); 1818 kobject_init(&ca->kobj, &bch_cache_ktype); 1819 1820 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 1821 1822 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 1823 1824 if (!init_fifo(&ca->free[RESERVE_BTREE], 8, GFP_KERNEL) || 1825 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 1826 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 1827 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 1828 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 1829 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 1830 !(ca->buckets = vzalloc(sizeof(struct bucket) * 1831 ca->sb.nbuckets)) || 1832 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 1833 2, GFP_KERNEL)) || 1834 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 1835 return -ENOMEM; 1836 1837 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 1838 1839 for_each_bucket(b, ca) 1840 atomic_set(&b->pin, 0); 1841 1842 return 0; 1843 } 1844 1845 static int register_cache(struct cache_sb *sb, struct page *sb_page, 1846 struct block_device *bdev, struct cache *ca) 1847 { 1848 char name[BDEVNAME_SIZE]; 1849 const char *err = NULL; /* must be set for any error case */ 1850 int ret = 0; 1851 1852 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 1853 ca->bdev = bdev; 1854 ca->bdev->bd_holder = ca; 1855 1856 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 1857 ca->sb_bio.bi_io_vec[0].bv_page = sb_page; 1858 get_page(sb_page); 1859 1860 if (blk_queue_discard(bdev_get_queue(ca->bdev))) 1861 ca->discard = CACHE_DISCARD(&ca->sb); 1862 1863 ret = cache_alloc(ca); 1864 if (ret != 0) { 1865 if (ret == -ENOMEM) 1866 err = "cache_alloc(): -ENOMEM"; 1867 else 1868 err = "cache_alloc(): unknown error"; 1869 goto err; 1870 } 1871 1872 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 1873 err = "error calling kobject_add"; 1874 ret = -ENOMEM; 1875 goto out; 1876 } 1877 1878 mutex_lock(&bch_register_lock); 1879 err = register_cache_set(ca); 1880 mutex_unlock(&bch_register_lock); 1881 1882 if (err) { 1883 ret = -ENODEV; 1884 goto out; 1885 } 1886 1887 pr_info("registered cache device %s", bdevname(bdev, name)); 1888 1889 out: 1890 kobject_put(&ca->kobj); 1891 1892 err: 1893 if (err) 1894 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1895 1896 return ret; 1897 } 1898 1899 /* Global interfaces/init */ 1900 1901 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 1902 const char *, size_t); 1903 1904 kobj_attribute_write(register, register_bcache); 1905 kobj_attribute_write(register_quiet, register_bcache); 1906 1907 static bool bch_is_open_backing(struct block_device *bdev) { 1908 struct cache_set *c, *tc; 1909 struct cached_dev *dc, *t; 1910 1911 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1912 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 1913 if (dc->bdev == bdev) 1914 return true; 1915 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1916 if (dc->bdev == bdev) 1917 return true; 1918 return false; 1919 } 1920 1921 static bool bch_is_open_cache(struct block_device *bdev) { 1922 struct cache_set *c, *tc; 1923 struct cache *ca; 1924 unsigned i; 1925 1926 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1927 for_each_cache(ca, c, i) 1928 if (ca->bdev == bdev) 1929 return true; 1930 return false; 1931 } 1932 1933 static bool bch_is_open(struct block_device *bdev) { 1934 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 1935 } 1936 1937 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 1938 const char *buffer, size_t size) 1939 { 1940 ssize_t ret = size; 1941 const char *err = "cannot allocate memory"; 1942 char *path = NULL; 1943 struct cache_sb *sb = NULL; 1944 struct block_device *bdev = NULL; 1945 struct page *sb_page = NULL; 1946 1947 if (!try_module_get(THIS_MODULE)) 1948 return -EBUSY; 1949 1950 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || 1951 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) 1952 goto err; 1953 1954 err = "failed to open device"; 1955 bdev = blkdev_get_by_path(strim(path), 1956 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 1957 sb); 1958 if (IS_ERR(bdev)) { 1959 if (bdev == ERR_PTR(-EBUSY)) { 1960 bdev = lookup_bdev(strim(path)); 1961 mutex_lock(&bch_register_lock); 1962 if (!IS_ERR(bdev) && bch_is_open(bdev)) 1963 err = "device already registered"; 1964 else 1965 err = "device busy"; 1966 mutex_unlock(&bch_register_lock); 1967 if (attr == &ksysfs_register_quiet) 1968 goto out; 1969 } 1970 goto err; 1971 } 1972 1973 err = "failed to set blocksize"; 1974 if (set_blocksize(bdev, 4096)) 1975 goto err_close; 1976 1977 err = read_super(sb, bdev, &sb_page); 1978 if (err) 1979 goto err_close; 1980 1981 if (SB_IS_BDEV(sb)) { 1982 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 1983 if (!dc) 1984 goto err_close; 1985 1986 mutex_lock(&bch_register_lock); 1987 register_bdev(sb, sb_page, bdev, dc); 1988 mutex_unlock(&bch_register_lock); 1989 } else { 1990 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 1991 if (!ca) 1992 goto err_close; 1993 1994 if (register_cache(sb, sb_page, bdev, ca) != 0) 1995 goto err_close; 1996 } 1997 out: 1998 if (sb_page) 1999 put_page(sb_page); 2000 kfree(sb); 2001 kfree(path); 2002 module_put(THIS_MODULE); 2003 return ret; 2004 2005 err_close: 2006 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2007 err: 2008 pr_info("error opening %s: %s", path, err); 2009 ret = -EINVAL; 2010 goto out; 2011 } 2012 2013 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2014 { 2015 if (code == SYS_DOWN || 2016 code == SYS_HALT || 2017 code == SYS_POWER_OFF) { 2018 DEFINE_WAIT(wait); 2019 unsigned long start = jiffies; 2020 bool stopped = false; 2021 2022 struct cache_set *c, *tc; 2023 struct cached_dev *dc, *tdc; 2024 2025 mutex_lock(&bch_register_lock); 2026 2027 if (list_empty(&bch_cache_sets) && 2028 list_empty(&uncached_devices)) 2029 goto out; 2030 2031 pr_info("Stopping all devices:"); 2032 2033 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2034 bch_cache_set_stop(c); 2035 2036 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2037 bcache_device_stop(&dc->disk); 2038 2039 /* What's a condition variable? */ 2040 while (1) { 2041 long timeout = start + 2 * HZ - jiffies; 2042 2043 stopped = list_empty(&bch_cache_sets) && 2044 list_empty(&uncached_devices); 2045 2046 if (timeout < 0 || stopped) 2047 break; 2048 2049 prepare_to_wait(&unregister_wait, &wait, 2050 TASK_UNINTERRUPTIBLE); 2051 2052 mutex_unlock(&bch_register_lock); 2053 schedule_timeout(timeout); 2054 mutex_lock(&bch_register_lock); 2055 } 2056 2057 finish_wait(&unregister_wait, &wait); 2058 2059 if (stopped) 2060 pr_info("All devices stopped"); 2061 else 2062 pr_notice("Timeout waiting for devices to be closed"); 2063 out: 2064 mutex_unlock(&bch_register_lock); 2065 } 2066 2067 return NOTIFY_DONE; 2068 } 2069 2070 static struct notifier_block reboot = { 2071 .notifier_call = bcache_reboot, 2072 .priority = INT_MAX, /* before any real devices */ 2073 }; 2074 2075 static void bcache_exit(void) 2076 { 2077 bch_debug_exit(); 2078 bch_request_exit(); 2079 if (bcache_kobj) 2080 kobject_put(bcache_kobj); 2081 if (bcache_wq) 2082 destroy_workqueue(bcache_wq); 2083 if (bcache_major) 2084 unregister_blkdev(bcache_major, "bcache"); 2085 unregister_reboot_notifier(&reboot); 2086 } 2087 2088 static int __init bcache_init(void) 2089 { 2090 static const struct attribute *files[] = { 2091 &ksysfs_register.attr, 2092 &ksysfs_register_quiet.attr, 2093 NULL 2094 }; 2095 2096 mutex_init(&bch_register_lock); 2097 init_waitqueue_head(&unregister_wait); 2098 register_reboot_notifier(&reboot); 2099 closure_debug_init(); 2100 2101 bcache_major = register_blkdev(0, "bcache"); 2102 if (bcache_major < 0) { 2103 unregister_reboot_notifier(&reboot); 2104 return bcache_major; 2105 } 2106 2107 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) || 2108 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || 2109 sysfs_create_files(bcache_kobj, files) || 2110 bch_request_init() || 2111 bch_debug_init(bcache_kobj)) 2112 goto err; 2113 2114 return 0; 2115 err: 2116 bcache_exit(); 2117 return -ENOMEM; 2118 } 2119 2120 module_exit(bcache_exit); 2121 module_init(bcache_init); 2122