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_error, "writing superblock"); 275 closure_put(&ca->set->sb_write); 276 } 277 278 static void bcache_write_super_unlock(struct closure *cl) 279 { 280 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 281 282 up(&c->sb_write_mutex); 283 } 284 285 void bcache_write_super(struct cache_set *c) 286 { 287 struct closure *cl = &c->sb_write; 288 struct cache *ca; 289 unsigned i; 290 291 down(&c->sb_write_mutex); 292 closure_init(cl, &c->cl); 293 294 c->sb.seq++; 295 296 for_each_cache(ca, c, i) { 297 struct bio *bio = &ca->sb_bio; 298 299 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 300 ca->sb.seq = c->sb.seq; 301 ca->sb.last_mount = c->sb.last_mount; 302 303 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 304 305 bio_reset(bio); 306 bio->bi_bdev = ca->bdev; 307 bio->bi_end_io = write_super_endio; 308 bio->bi_private = ca; 309 310 closure_get(cl); 311 __write_super(&ca->sb, bio); 312 } 313 314 closure_return_with_destructor(cl, bcache_write_super_unlock); 315 } 316 317 /* UUID io */ 318 319 static void uuid_endio(struct bio *bio) 320 { 321 struct closure *cl = bio->bi_private; 322 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 323 324 cache_set_err_on(bio->bi_error, c, "accessing uuids"); 325 bch_bbio_free(bio, c); 326 closure_put(cl); 327 } 328 329 static void uuid_io_unlock(struct closure *cl) 330 { 331 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 332 333 up(&c->uuid_write_mutex); 334 } 335 336 static void uuid_io(struct cache_set *c, 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_error, 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 !(d->disk = alloc_disk(BCACHE_MINORS))) { 787 ida_simple_remove(&bcache_minor, minor); 788 return -ENOMEM; 789 } 790 791 set_capacity(d->disk, sectors); 792 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", minor); 793 794 d->disk->major = bcache_major; 795 d->disk->first_minor = minor; 796 d->disk->fops = &bcache_ops; 797 d->disk->private_data = d; 798 799 q = blk_alloc_queue(GFP_KERNEL); 800 if (!q) 801 return -ENOMEM; 802 803 blk_queue_make_request(q, NULL); 804 d->disk->queue = q; 805 q->queuedata = d; 806 q->backing_dev_info->congested_data = d; 807 q->limits.max_hw_sectors = UINT_MAX; 808 q->limits.max_sectors = UINT_MAX; 809 q->limits.max_segment_size = UINT_MAX; 810 q->limits.max_segments = BIO_MAX_PAGES; 811 blk_queue_max_discard_sectors(q, UINT_MAX); 812 q->limits.discard_granularity = 512; 813 q->limits.io_min = block_size; 814 q->limits.logical_block_size = block_size; 815 q->limits.physical_block_size = block_size; 816 set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags); 817 clear_bit(QUEUE_FLAG_ADD_RANDOM, &d->disk->queue->queue_flags); 818 set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags); 819 820 blk_queue_write_cache(q, true, true); 821 822 return 0; 823 } 824 825 /* Cached device */ 826 827 static void calc_cached_dev_sectors(struct cache_set *c) 828 { 829 uint64_t sectors = 0; 830 struct cached_dev *dc; 831 832 list_for_each_entry(dc, &c->cached_devs, list) 833 sectors += bdev_sectors(dc->bdev); 834 835 c->cached_dev_sectors = sectors; 836 } 837 838 void bch_cached_dev_run(struct cached_dev *dc) 839 { 840 struct bcache_device *d = &dc->disk; 841 char buf[SB_LABEL_SIZE + 1]; 842 char *env[] = { 843 "DRIVER=bcache", 844 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 845 NULL, 846 NULL, 847 }; 848 849 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 850 buf[SB_LABEL_SIZE] = '\0'; 851 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 852 853 if (atomic_xchg(&dc->running, 1)) { 854 kfree(env[1]); 855 kfree(env[2]); 856 return; 857 } 858 859 if (!d->c && 860 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 861 struct closure cl; 862 closure_init_stack(&cl); 863 864 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 865 bch_write_bdev_super(dc, &cl); 866 closure_sync(&cl); 867 } 868 869 add_disk(d->disk); 870 bd_link_disk_holder(dc->bdev, dc->disk.disk); 871 /* won't show up in the uevent file, use udevadm monitor -e instead 872 * only class / kset properties are persistent */ 873 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 874 kfree(env[1]); 875 kfree(env[2]); 876 877 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 878 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 879 pr_debug("error creating sysfs link"); 880 } 881 882 static void cached_dev_detach_finish(struct work_struct *w) 883 { 884 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 885 char buf[BDEVNAME_SIZE]; 886 struct closure cl; 887 closure_init_stack(&cl); 888 889 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 890 BUG_ON(atomic_read(&dc->count)); 891 892 mutex_lock(&bch_register_lock); 893 894 memset(&dc->sb.set_uuid, 0, 16); 895 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 896 897 bch_write_bdev_super(dc, &cl); 898 closure_sync(&cl); 899 900 bcache_device_detach(&dc->disk); 901 list_move(&dc->list, &uncached_devices); 902 903 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 904 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 905 906 mutex_unlock(&bch_register_lock); 907 908 pr_info("Caching disabled for %s", bdevname(dc->bdev, buf)); 909 910 /* Drop ref we took in cached_dev_detach() */ 911 closure_put(&dc->disk.cl); 912 } 913 914 void bch_cached_dev_detach(struct cached_dev *dc) 915 { 916 lockdep_assert_held(&bch_register_lock); 917 918 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 919 return; 920 921 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 922 return; 923 924 /* 925 * Block the device from being closed and freed until we're finished 926 * detaching 927 */ 928 closure_get(&dc->disk.cl); 929 930 bch_writeback_queue(dc); 931 cached_dev_put(dc); 932 } 933 934 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c) 935 { 936 uint32_t rtime = cpu_to_le32(get_seconds()); 937 struct uuid_entry *u; 938 char buf[BDEVNAME_SIZE]; 939 940 bdevname(dc->bdev, buf); 941 942 if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)) 943 return -ENOENT; 944 945 if (dc->disk.c) { 946 pr_err("Can't attach %s: already attached", buf); 947 return -EINVAL; 948 } 949 950 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 951 pr_err("Can't attach %s: shutting down", buf); 952 return -EINVAL; 953 } 954 955 if (dc->sb.block_size < c->sb.block_size) { 956 /* Will die */ 957 pr_err("Couldn't attach %s: block size less than set's block size", 958 buf); 959 return -EINVAL; 960 } 961 962 u = uuid_find(c, dc->sb.uuid); 963 964 if (u && 965 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 966 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 967 memcpy(u->uuid, invalid_uuid, 16); 968 u->invalidated = cpu_to_le32(get_seconds()); 969 u = NULL; 970 } 971 972 if (!u) { 973 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 974 pr_err("Couldn't find uuid for %s in set", buf); 975 return -ENOENT; 976 } 977 978 u = uuid_find_empty(c); 979 if (!u) { 980 pr_err("Not caching %s, no room for UUID", buf); 981 return -EINVAL; 982 } 983 } 984 985 /* Deadlocks since we're called via sysfs... 986 sysfs_remove_file(&dc->kobj, &sysfs_attach); 987 */ 988 989 if (bch_is_zero(u->uuid, 16)) { 990 struct closure cl; 991 closure_init_stack(&cl); 992 993 memcpy(u->uuid, dc->sb.uuid, 16); 994 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 995 u->first_reg = u->last_reg = rtime; 996 bch_uuid_write(c); 997 998 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 999 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1000 1001 bch_write_bdev_super(dc, &cl); 1002 closure_sync(&cl); 1003 } else { 1004 u->last_reg = rtime; 1005 bch_uuid_write(c); 1006 } 1007 1008 bcache_device_attach(&dc->disk, c, u - c->uuids); 1009 list_move(&dc->list, &c->cached_devs); 1010 calc_cached_dev_sectors(c); 1011 1012 smp_wmb(); 1013 /* 1014 * dc->c must be set before dc->count != 0 - paired with the mb in 1015 * cached_dev_get() 1016 */ 1017 atomic_set(&dc->count, 1); 1018 1019 /* Block writeback thread, but spawn it */ 1020 down_write(&dc->writeback_lock); 1021 if (bch_cached_dev_writeback_start(dc)) { 1022 up_write(&dc->writeback_lock); 1023 return -ENOMEM; 1024 } 1025 1026 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1027 bch_sectors_dirty_init(dc); 1028 atomic_set(&dc->has_dirty, 1); 1029 atomic_inc(&dc->count); 1030 bch_writeback_queue(dc); 1031 } 1032 1033 bch_cached_dev_run(dc); 1034 bcache_device_link(&dc->disk, c, "bdev"); 1035 1036 /* Allow the writeback thread to proceed */ 1037 up_write(&dc->writeback_lock); 1038 1039 pr_info("Caching %s as %s on set %pU", 1040 bdevname(dc->bdev, buf), dc->disk.disk->disk_name, 1041 dc->disk.c->sb.set_uuid); 1042 return 0; 1043 } 1044 1045 void bch_cached_dev_release(struct kobject *kobj) 1046 { 1047 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1048 disk.kobj); 1049 kfree(dc); 1050 module_put(THIS_MODULE); 1051 } 1052 1053 static void cached_dev_free(struct closure *cl) 1054 { 1055 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1056 1057 cancel_delayed_work_sync(&dc->writeback_rate_update); 1058 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1059 kthread_stop(dc->writeback_thread); 1060 1061 mutex_lock(&bch_register_lock); 1062 1063 if (atomic_read(&dc->running)) 1064 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1065 bcache_device_free(&dc->disk); 1066 list_del(&dc->list); 1067 1068 mutex_unlock(&bch_register_lock); 1069 1070 if (!IS_ERR_OR_NULL(dc->bdev)) 1071 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1072 1073 wake_up(&unregister_wait); 1074 1075 kobject_put(&dc->disk.kobj); 1076 } 1077 1078 static void cached_dev_flush(struct closure *cl) 1079 { 1080 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1081 struct bcache_device *d = &dc->disk; 1082 1083 mutex_lock(&bch_register_lock); 1084 bcache_device_unlink(d); 1085 mutex_unlock(&bch_register_lock); 1086 1087 bch_cache_accounting_destroy(&dc->accounting); 1088 kobject_del(&d->kobj); 1089 1090 continue_at(cl, cached_dev_free, system_wq); 1091 } 1092 1093 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1094 { 1095 int ret; 1096 struct io *io; 1097 struct request_queue *q = bdev_get_queue(dc->bdev); 1098 1099 __module_get(THIS_MODULE); 1100 INIT_LIST_HEAD(&dc->list); 1101 closure_init(&dc->disk.cl, NULL); 1102 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1103 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1104 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1105 sema_init(&dc->sb_write_mutex, 1); 1106 INIT_LIST_HEAD(&dc->io_lru); 1107 spin_lock_init(&dc->io_lock); 1108 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1109 1110 dc->sequential_cutoff = 4 << 20; 1111 1112 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1113 list_add(&io->lru, &dc->io_lru); 1114 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1115 } 1116 1117 dc->disk.stripe_size = q->limits.io_opt >> 9; 1118 1119 if (dc->disk.stripe_size) 1120 dc->partial_stripes_expensive = 1121 q->limits.raid_partial_stripes_expensive; 1122 1123 ret = bcache_device_init(&dc->disk, block_size, 1124 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1125 if (ret) 1126 return ret; 1127 1128 set_capacity(dc->disk.disk, 1129 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1130 1131 dc->disk.disk->queue->backing_dev_info->ra_pages = 1132 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1133 q->backing_dev_info->ra_pages); 1134 1135 bch_cached_dev_request_init(dc); 1136 bch_cached_dev_writeback_init(dc); 1137 return 0; 1138 } 1139 1140 /* Cached device - bcache superblock */ 1141 1142 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1143 struct block_device *bdev, 1144 struct cached_dev *dc) 1145 { 1146 char name[BDEVNAME_SIZE]; 1147 const char *err = "cannot allocate memory"; 1148 struct cache_set *c; 1149 1150 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1151 dc->bdev = bdev; 1152 dc->bdev->bd_holder = dc; 1153 1154 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1155 dc->sb_bio.bi_io_vec[0].bv_page = sb_page; 1156 get_page(sb_page); 1157 1158 if (cached_dev_init(dc, sb->block_size << 9)) 1159 goto err; 1160 1161 err = "error creating kobject"; 1162 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1163 "bcache")) 1164 goto err; 1165 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1166 goto err; 1167 1168 pr_info("registered backing device %s", bdevname(bdev, name)); 1169 1170 list_add(&dc->list, &uncached_devices); 1171 list_for_each_entry(c, &bch_cache_sets, list) 1172 bch_cached_dev_attach(dc, c); 1173 1174 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1175 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1176 bch_cached_dev_run(dc); 1177 1178 return; 1179 err: 1180 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1181 bcache_device_stop(&dc->disk); 1182 } 1183 1184 /* Flash only volumes */ 1185 1186 void bch_flash_dev_release(struct kobject *kobj) 1187 { 1188 struct bcache_device *d = container_of(kobj, struct bcache_device, 1189 kobj); 1190 kfree(d); 1191 } 1192 1193 static void flash_dev_free(struct closure *cl) 1194 { 1195 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1196 mutex_lock(&bch_register_lock); 1197 bcache_device_free(d); 1198 mutex_unlock(&bch_register_lock); 1199 kobject_put(&d->kobj); 1200 } 1201 1202 static void flash_dev_flush(struct closure *cl) 1203 { 1204 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1205 1206 mutex_lock(&bch_register_lock); 1207 bcache_device_unlink(d); 1208 mutex_unlock(&bch_register_lock); 1209 kobject_del(&d->kobj); 1210 continue_at(cl, flash_dev_free, system_wq); 1211 } 1212 1213 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1214 { 1215 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1216 GFP_KERNEL); 1217 if (!d) 1218 return -ENOMEM; 1219 1220 closure_init(&d->cl, NULL); 1221 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1222 1223 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1224 1225 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1226 goto err; 1227 1228 bcache_device_attach(d, c, u - c->uuids); 1229 bch_flash_dev_request_init(d); 1230 add_disk(d->disk); 1231 1232 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1233 goto err; 1234 1235 bcache_device_link(d, c, "volume"); 1236 1237 return 0; 1238 err: 1239 kobject_put(&d->kobj); 1240 return -ENOMEM; 1241 } 1242 1243 static int flash_devs_run(struct cache_set *c) 1244 { 1245 int ret = 0; 1246 struct uuid_entry *u; 1247 1248 for (u = c->uuids; 1249 u < c->uuids + c->nr_uuids && !ret; 1250 u++) 1251 if (UUID_FLASH_ONLY(u)) 1252 ret = flash_dev_run(c, u); 1253 1254 return ret; 1255 } 1256 1257 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1258 { 1259 struct uuid_entry *u; 1260 1261 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1262 return -EINTR; 1263 1264 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1265 return -EPERM; 1266 1267 u = uuid_find_empty(c); 1268 if (!u) { 1269 pr_err("Can't create volume, no room for UUID"); 1270 return -EINVAL; 1271 } 1272 1273 get_random_bytes(u->uuid, 16); 1274 memset(u->label, 0, 32); 1275 u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); 1276 1277 SET_UUID_FLASH_ONLY(u, 1); 1278 u->sectors = size >> 9; 1279 1280 bch_uuid_write(c); 1281 1282 return flash_dev_run(c, u); 1283 } 1284 1285 /* Cache set */ 1286 1287 __printf(2, 3) 1288 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1289 { 1290 va_list args; 1291 1292 if (c->on_error != ON_ERROR_PANIC && 1293 test_bit(CACHE_SET_STOPPING, &c->flags)) 1294 return false; 1295 1296 /* XXX: we can be called from atomic context 1297 acquire_console_sem(); 1298 */ 1299 1300 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1301 1302 va_start(args, fmt); 1303 vprintk(fmt, args); 1304 va_end(args); 1305 1306 printk(", disabling caching\n"); 1307 1308 if (c->on_error == ON_ERROR_PANIC) 1309 panic("panic forced after error\n"); 1310 1311 bch_cache_set_unregister(c); 1312 return true; 1313 } 1314 1315 void bch_cache_set_release(struct kobject *kobj) 1316 { 1317 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1318 kfree(c); 1319 module_put(THIS_MODULE); 1320 } 1321 1322 static void cache_set_free(struct closure *cl) 1323 { 1324 struct cache_set *c = container_of(cl, struct cache_set, cl); 1325 struct cache *ca; 1326 unsigned i; 1327 1328 if (!IS_ERR_OR_NULL(c->debug)) 1329 debugfs_remove(c->debug); 1330 1331 bch_open_buckets_free(c); 1332 bch_btree_cache_free(c); 1333 bch_journal_free(c); 1334 1335 for_each_cache(ca, c, i) 1336 if (ca) { 1337 ca->set = NULL; 1338 c->cache[ca->sb.nr_this_dev] = NULL; 1339 kobject_put(&ca->kobj); 1340 } 1341 1342 bch_bset_sort_state_free(&c->sort); 1343 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1344 1345 if (c->moving_gc_wq) 1346 destroy_workqueue(c->moving_gc_wq); 1347 if (c->bio_split) 1348 bioset_free(c->bio_split); 1349 if (c->fill_iter) 1350 mempool_destroy(c->fill_iter); 1351 if (c->bio_meta) 1352 mempool_destroy(c->bio_meta); 1353 if (c->search) 1354 mempool_destroy(c->search); 1355 kfree(c->devices); 1356 1357 mutex_lock(&bch_register_lock); 1358 list_del(&c->list); 1359 mutex_unlock(&bch_register_lock); 1360 1361 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1362 wake_up(&unregister_wait); 1363 1364 closure_debug_destroy(&c->cl); 1365 kobject_put(&c->kobj); 1366 } 1367 1368 static void cache_set_flush(struct closure *cl) 1369 { 1370 struct cache_set *c = container_of(cl, struct cache_set, caching); 1371 struct cache *ca; 1372 struct btree *b; 1373 unsigned i; 1374 1375 if (!c) 1376 closure_return(cl); 1377 1378 bch_cache_accounting_destroy(&c->accounting); 1379 1380 kobject_put(&c->internal); 1381 kobject_del(&c->kobj); 1382 1383 if (c->gc_thread) 1384 kthread_stop(c->gc_thread); 1385 1386 if (!IS_ERR_OR_NULL(c->root)) 1387 list_add(&c->root->list, &c->btree_cache); 1388 1389 /* Should skip this if we're unregistering because of an error */ 1390 list_for_each_entry(b, &c->btree_cache, list) { 1391 mutex_lock(&b->write_lock); 1392 if (btree_node_dirty(b)) 1393 __bch_btree_node_write(b, NULL); 1394 mutex_unlock(&b->write_lock); 1395 } 1396 1397 for_each_cache(ca, c, i) 1398 if (ca->alloc_thread) 1399 kthread_stop(ca->alloc_thread); 1400 1401 if (c->journal.cur) { 1402 cancel_delayed_work_sync(&c->journal.work); 1403 /* flush last journal entry if needed */ 1404 c->journal.work.work.func(&c->journal.work.work); 1405 } 1406 1407 closure_return(cl); 1408 } 1409 1410 static void __cache_set_unregister(struct closure *cl) 1411 { 1412 struct cache_set *c = container_of(cl, struct cache_set, caching); 1413 struct cached_dev *dc; 1414 size_t i; 1415 1416 mutex_lock(&bch_register_lock); 1417 1418 for (i = 0; i < c->nr_uuids; i++) 1419 if (c->devices[i]) { 1420 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1421 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1422 dc = container_of(c->devices[i], 1423 struct cached_dev, disk); 1424 bch_cached_dev_detach(dc); 1425 } else { 1426 bcache_device_stop(c->devices[i]); 1427 } 1428 } 1429 1430 mutex_unlock(&bch_register_lock); 1431 1432 continue_at(cl, cache_set_flush, system_wq); 1433 } 1434 1435 void bch_cache_set_stop(struct cache_set *c) 1436 { 1437 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1438 closure_queue(&c->caching); 1439 } 1440 1441 void bch_cache_set_unregister(struct cache_set *c) 1442 { 1443 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1444 bch_cache_set_stop(c); 1445 } 1446 1447 #define alloc_bucket_pages(gfp, c) \ 1448 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1449 1450 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1451 { 1452 int iter_size; 1453 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1454 if (!c) 1455 return NULL; 1456 1457 __module_get(THIS_MODULE); 1458 closure_init(&c->cl, NULL); 1459 set_closure_fn(&c->cl, cache_set_free, system_wq); 1460 1461 closure_init(&c->caching, &c->cl); 1462 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1463 1464 /* Maybe create continue_at_noreturn() and use it here? */ 1465 closure_set_stopped(&c->cl); 1466 closure_put(&c->cl); 1467 1468 kobject_init(&c->kobj, &bch_cache_set_ktype); 1469 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1470 1471 bch_cache_accounting_init(&c->accounting, &c->cl); 1472 1473 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1474 c->sb.block_size = sb->block_size; 1475 c->sb.bucket_size = sb->bucket_size; 1476 c->sb.nr_in_set = sb->nr_in_set; 1477 c->sb.last_mount = sb->last_mount; 1478 c->bucket_bits = ilog2(sb->bucket_size); 1479 c->block_bits = ilog2(sb->block_size); 1480 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1481 1482 c->btree_pages = bucket_pages(c); 1483 if (c->btree_pages > BTREE_MAX_PAGES) 1484 c->btree_pages = max_t(int, c->btree_pages / 4, 1485 BTREE_MAX_PAGES); 1486 1487 sema_init(&c->sb_write_mutex, 1); 1488 mutex_init(&c->bucket_lock); 1489 init_waitqueue_head(&c->btree_cache_wait); 1490 init_waitqueue_head(&c->bucket_wait); 1491 init_waitqueue_head(&c->gc_wait); 1492 sema_init(&c->uuid_write_mutex, 1); 1493 1494 spin_lock_init(&c->btree_gc_time.lock); 1495 spin_lock_init(&c->btree_split_time.lock); 1496 spin_lock_init(&c->btree_read_time.lock); 1497 1498 bch_moving_init_cache_set(c); 1499 1500 INIT_LIST_HEAD(&c->list); 1501 INIT_LIST_HEAD(&c->cached_devs); 1502 INIT_LIST_HEAD(&c->btree_cache); 1503 INIT_LIST_HEAD(&c->btree_cache_freeable); 1504 INIT_LIST_HEAD(&c->btree_cache_freed); 1505 INIT_LIST_HEAD(&c->data_buckets); 1506 1507 c->search = mempool_create_slab_pool(32, bch_search_cache); 1508 if (!c->search) 1509 goto err; 1510 1511 iter_size = (sb->bucket_size / sb->block_size + 1) * 1512 sizeof(struct btree_iter_set); 1513 1514 if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) || 1515 !(c->bio_meta = mempool_create_kmalloc_pool(2, 1516 sizeof(struct bbio) + sizeof(struct bio_vec) * 1517 bucket_pages(c))) || 1518 !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) || 1519 !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) || 1520 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1521 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1522 WQ_MEM_RECLAIM, 0)) || 1523 bch_journal_alloc(c) || 1524 bch_btree_cache_alloc(c) || 1525 bch_open_buckets_alloc(c) || 1526 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1527 goto err; 1528 1529 c->congested_read_threshold_us = 2000; 1530 c->congested_write_threshold_us = 20000; 1531 c->error_limit = 8 << IO_ERROR_SHIFT; 1532 1533 return c; 1534 err: 1535 bch_cache_set_unregister(c); 1536 return NULL; 1537 } 1538 1539 static void run_cache_set(struct cache_set *c) 1540 { 1541 const char *err = "cannot allocate memory"; 1542 struct cached_dev *dc, *t; 1543 struct cache *ca; 1544 struct closure cl; 1545 unsigned i; 1546 1547 closure_init_stack(&cl); 1548 1549 for_each_cache(ca, c, i) 1550 c->nbuckets += ca->sb.nbuckets; 1551 set_gc_sectors(c); 1552 1553 if (CACHE_SYNC(&c->sb)) { 1554 LIST_HEAD(journal); 1555 struct bkey *k; 1556 struct jset *j; 1557 1558 err = "cannot allocate memory for journal"; 1559 if (bch_journal_read(c, &journal)) 1560 goto err; 1561 1562 pr_debug("btree_journal_read() done"); 1563 1564 err = "no journal entries found"; 1565 if (list_empty(&journal)) 1566 goto err; 1567 1568 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1569 1570 err = "IO error reading priorities"; 1571 for_each_cache(ca, c, i) 1572 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1573 1574 /* 1575 * If prio_read() fails it'll call cache_set_error and we'll 1576 * tear everything down right away, but if we perhaps checked 1577 * sooner we could avoid journal replay. 1578 */ 1579 1580 k = &j->btree_root; 1581 1582 err = "bad btree root"; 1583 if (__bch_btree_ptr_invalid(c, k)) 1584 goto err; 1585 1586 err = "error reading btree root"; 1587 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1588 if (IS_ERR_OR_NULL(c->root)) 1589 goto err; 1590 1591 list_del_init(&c->root->list); 1592 rw_unlock(true, c->root); 1593 1594 err = uuid_read(c, j, &cl); 1595 if (err) 1596 goto err; 1597 1598 err = "error in recovery"; 1599 if (bch_btree_check(c)) 1600 goto err; 1601 1602 bch_journal_mark(c, &journal); 1603 bch_initial_gc_finish(c); 1604 pr_debug("btree_check() done"); 1605 1606 /* 1607 * bcache_journal_next() can't happen sooner, or 1608 * btree_gc_finish() will give spurious errors about last_gc > 1609 * gc_gen - this is a hack but oh well. 1610 */ 1611 bch_journal_next(&c->journal); 1612 1613 err = "error starting allocator thread"; 1614 for_each_cache(ca, c, i) 1615 if (bch_cache_allocator_start(ca)) 1616 goto err; 1617 1618 /* 1619 * First place it's safe to allocate: btree_check() and 1620 * btree_gc_finish() have to run before we have buckets to 1621 * allocate, and bch_bucket_alloc_set() might cause a journal 1622 * entry to be written so bcache_journal_next() has to be called 1623 * first. 1624 * 1625 * If the uuids were in the old format we have to rewrite them 1626 * before the next journal entry is written: 1627 */ 1628 if (j->version < BCACHE_JSET_VERSION_UUID) 1629 __uuid_write(c); 1630 1631 bch_journal_replay(c, &journal); 1632 } else { 1633 pr_notice("invalidating existing data"); 1634 1635 for_each_cache(ca, c, i) { 1636 unsigned j; 1637 1638 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1639 2, SB_JOURNAL_BUCKETS); 1640 1641 for (j = 0; j < ca->sb.keys; j++) 1642 ca->sb.d[j] = ca->sb.first_bucket + j; 1643 } 1644 1645 bch_initial_gc_finish(c); 1646 1647 err = "error starting allocator thread"; 1648 for_each_cache(ca, c, i) 1649 if (bch_cache_allocator_start(ca)) 1650 goto err; 1651 1652 mutex_lock(&c->bucket_lock); 1653 for_each_cache(ca, c, i) 1654 bch_prio_write(ca); 1655 mutex_unlock(&c->bucket_lock); 1656 1657 err = "cannot allocate new UUID bucket"; 1658 if (__uuid_write(c)) 1659 goto err; 1660 1661 err = "cannot allocate new btree root"; 1662 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1663 if (IS_ERR_OR_NULL(c->root)) 1664 goto err; 1665 1666 mutex_lock(&c->root->write_lock); 1667 bkey_copy_key(&c->root->key, &MAX_KEY); 1668 bch_btree_node_write(c->root, &cl); 1669 mutex_unlock(&c->root->write_lock); 1670 1671 bch_btree_set_root(c->root); 1672 rw_unlock(true, c->root); 1673 1674 /* 1675 * We don't want to write the first journal entry until 1676 * everything is set up - fortunately journal entries won't be 1677 * written until the SET_CACHE_SYNC() here: 1678 */ 1679 SET_CACHE_SYNC(&c->sb, true); 1680 1681 bch_journal_next(&c->journal); 1682 bch_journal_meta(c, &cl); 1683 } 1684 1685 err = "error starting gc thread"; 1686 if (bch_gc_thread_start(c)) 1687 goto err; 1688 1689 closure_sync(&cl); 1690 c->sb.last_mount = get_seconds(); 1691 bcache_write_super(c); 1692 1693 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1694 bch_cached_dev_attach(dc, c); 1695 1696 flash_devs_run(c); 1697 1698 set_bit(CACHE_SET_RUNNING, &c->flags); 1699 return; 1700 err: 1701 closure_sync(&cl); 1702 /* XXX: test this, it's broken */ 1703 bch_cache_set_error(c, "%s", err); 1704 } 1705 1706 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1707 { 1708 return ca->sb.block_size == c->sb.block_size && 1709 ca->sb.bucket_size == c->sb.bucket_size && 1710 ca->sb.nr_in_set == c->sb.nr_in_set; 1711 } 1712 1713 static const char *register_cache_set(struct cache *ca) 1714 { 1715 char buf[12]; 1716 const char *err = "cannot allocate memory"; 1717 struct cache_set *c; 1718 1719 list_for_each_entry(c, &bch_cache_sets, list) 1720 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1721 if (c->cache[ca->sb.nr_this_dev]) 1722 return "duplicate cache set member"; 1723 1724 if (!can_attach_cache(ca, c)) 1725 return "cache sb does not match set"; 1726 1727 if (!CACHE_SYNC(&ca->sb)) 1728 SET_CACHE_SYNC(&c->sb, false); 1729 1730 goto found; 1731 } 1732 1733 c = bch_cache_set_alloc(&ca->sb); 1734 if (!c) 1735 return err; 1736 1737 err = "error creating kobject"; 1738 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1739 kobject_add(&c->internal, &c->kobj, "internal")) 1740 goto err; 1741 1742 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1743 goto err; 1744 1745 bch_debug_init_cache_set(c); 1746 1747 list_add(&c->list, &bch_cache_sets); 1748 found: 1749 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1750 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1751 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1752 goto err; 1753 1754 if (ca->sb.seq > c->sb.seq) { 1755 c->sb.version = ca->sb.version; 1756 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1757 c->sb.flags = ca->sb.flags; 1758 c->sb.seq = ca->sb.seq; 1759 pr_debug("set version = %llu", c->sb.version); 1760 } 1761 1762 kobject_get(&ca->kobj); 1763 ca->set = c; 1764 ca->set->cache[ca->sb.nr_this_dev] = ca; 1765 c->cache_by_alloc[c->caches_loaded++] = ca; 1766 1767 if (c->caches_loaded == c->sb.nr_in_set) 1768 run_cache_set(c); 1769 1770 return NULL; 1771 err: 1772 bch_cache_set_unregister(c); 1773 return err; 1774 } 1775 1776 /* Cache device */ 1777 1778 void bch_cache_release(struct kobject *kobj) 1779 { 1780 struct cache *ca = container_of(kobj, struct cache, kobj); 1781 unsigned i; 1782 1783 if (ca->set) { 1784 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 1785 ca->set->cache[ca->sb.nr_this_dev] = NULL; 1786 } 1787 1788 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 1789 kfree(ca->prio_buckets); 1790 vfree(ca->buckets); 1791 1792 free_heap(&ca->heap); 1793 free_fifo(&ca->free_inc); 1794 1795 for (i = 0; i < RESERVE_NR; i++) 1796 free_fifo(&ca->free[i]); 1797 1798 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 1799 put_page(ca->sb_bio.bi_io_vec[0].bv_page); 1800 1801 if (!IS_ERR_OR_NULL(ca->bdev)) 1802 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1803 1804 kfree(ca); 1805 module_put(THIS_MODULE); 1806 } 1807 1808 static int cache_alloc(struct cache *ca) 1809 { 1810 size_t free; 1811 struct bucket *b; 1812 1813 __module_get(THIS_MODULE); 1814 kobject_init(&ca->kobj, &bch_cache_ktype); 1815 1816 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 1817 1818 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 1819 1820 if (!init_fifo(&ca->free[RESERVE_BTREE], 8, GFP_KERNEL) || 1821 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 1822 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 1823 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 1824 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 1825 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 1826 !(ca->buckets = vzalloc(sizeof(struct bucket) * 1827 ca->sb.nbuckets)) || 1828 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 1829 2, GFP_KERNEL)) || 1830 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 1831 return -ENOMEM; 1832 1833 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 1834 1835 for_each_bucket(b, ca) 1836 atomic_set(&b->pin, 0); 1837 1838 return 0; 1839 } 1840 1841 static int register_cache(struct cache_sb *sb, struct page *sb_page, 1842 struct block_device *bdev, struct cache *ca) 1843 { 1844 char name[BDEVNAME_SIZE]; 1845 const char *err = NULL; /* must be set for any error case */ 1846 int ret = 0; 1847 1848 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 1849 ca->bdev = bdev; 1850 ca->bdev->bd_holder = ca; 1851 1852 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 1853 ca->sb_bio.bi_io_vec[0].bv_page = sb_page; 1854 get_page(sb_page); 1855 1856 if (blk_queue_discard(bdev_get_queue(ca->bdev))) 1857 ca->discard = CACHE_DISCARD(&ca->sb); 1858 1859 ret = cache_alloc(ca); 1860 if (ret != 0) { 1861 if (ret == -ENOMEM) 1862 err = "cache_alloc(): -ENOMEM"; 1863 else 1864 err = "cache_alloc(): unknown error"; 1865 goto err; 1866 } 1867 1868 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 1869 err = "error calling kobject_add"; 1870 ret = -ENOMEM; 1871 goto out; 1872 } 1873 1874 mutex_lock(&bch_register_lock); 1875 err = register_cache_set(ca); 1876 mutex_unlock(&bch_register_lock); 1877 1878 if (err) { 1879 ret = -ENODEV; 1880 goto out; 1881 } 1882 1883 pr_info("registered cache device %s", bdevname(bdev, name)); 1884 1885 out: 1886 kobject_put(&ca->kobj); 1887 1888 err: 1889 if (err) 1890 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1891 1892 return ret; 1893 } 1894 1895 /* Global interfaces/init */ 1896 1897 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 1898 const char *, size_t); 1899 1900 kobj_attribute_write(register, register_bcache); 1901 kobj_attribute_write(register_quiet, register_bcache); 1902 1903 static bool bch_is_open_backing(struct block_device *bdev) { 1904 struct cache_set *c, *tc; 1905 struct cached_dev *dc, *t; 1906 1907 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1908 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 1909 if (dc->bdev == bdev) 1910 return true; 1911 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1912 if (dc->bdev == bdev) 1913 return true; 1914 return false; 1915 } 1916 1917 static bool bch_is_open_cache(struct block_device *bdev) { 1918 struct cache_set *c, *tc; 1919 struct cache *ca; 1920 unsigned i; 1921 1922 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1923 for_each_cache(ca, c, i) 1924 if (ca->bdev == bdev) 1925 return true; 1926 return false; 1927 } 1928 1929 static bool bch_is_open(struct block_device *bdev) { 1930 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 1931 } 1932 1933 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 1934 const char *buffer, size_t size) 1935 { 1936 ssize_t ret = size; 1937 const char *err = "cannot allocate memory"; 1938 char *path = NULL; 1939 struct cache_sb *sb = NULL; 1940 struct block_device *bdev = NULL; 1941 struct page *sb_page = NULL; 1942 1943 if (!try_module_get(THIS_MODULE)) 1944 return -EBUSY; 1945 1946 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || 1947 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) 1948 goto err; 1949 1950 err = "failed to open device"; 1951 bdev = blkdev_get_by_path(strim(path), 1952 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 1953 sb); 1954 if (IS_ERR(bdev)) { 1955 if (bdev == ERR_PTR(-EBUSY)) { 1956 bdev = lookup_bdev(strim(path)); 1957 mutex_lock(&bch_register_lock); 1958 if (!IS_ERR(bdev) && bch_is_open(bdev)) 1959 err = "device already registered"; 1960 else 1961 err = "device busy"; 1962 mutex_unlock(&bch_register_lock); 1963 if (attr == &ksysfs_register_quiet) 1964 goto out; 1965 } 1966 goto err; 1967 } 1968 1969 err = "failed to set blocksize"; 1970 if (set_blocksize(bdev, 4096)) 1971 goto err_close; 1972 1973 err = read_super(sb, bdev, &sb_page); 1974 if (err) 1975 goto err_close; 1976 1977 if (SB_IS_BDEV(sb)) { 1978 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 1979 if (!dc) 1980 goto err_close; 1981 1982 mutex_lock(&bch_register_lock); 1983 register_bdev(sb, sb_page, bdev, dc); 1984 mutex_unlock(&bch_register_lock); 1985 } else { 1986 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 1987 if (!ca) 1988 goto err_close; 1989 1990 if (register_cache(sb, sb_page, bdev, ca) != 0) 1991 goto err_close; 1992 } 1993 out: 1994 if (sb_page) 1995 put_page(sb_page); 1996 kfree(sb); 1997 kfree(path); 1998 module_put(THIS_MODULE); 1999 return ret; 2000 2001 err_close: 2002 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2003 err: 2004 pr_info("error opening %s: %s", path, err); 2005 ret = -EINVAL; 2006 goto out; 2007 } 2008 2009 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2010 { 2011 if (code == SYS_DOWN || 2012 code == SYS_HALT || 2013 code == SYS_POWER_OFF) { 2014 DEFINE_WAIT(wait); 2015 unsigned long start = jiffies; 2016 bool stopped = false; 2017 2018 struct cache_set *c, *tc; 2019 struct cached_dev *dc, *tdc; 2020 2021 mutex_lock(&bch_register_lock); 2022 2023 if (list_empty(&bch_cache_sets) && 2024 list_empty(&uncached_devices)) 2025 goto out; 2026 2027 pr_info("Stopping all devices:"); 2028 2029 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2030 bch_cache_set_stop(c); 2031 2032 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2033 bcache_device_stop(&dc->disk); 2034 2035 /* What's a condition variable? */ 2036 while (1) { 2037 long timeout = start + 2 * HZ - jiffies; 2038 2039 stopped = list_empty(&bch_cache_sets) && 2040 list_empty(&uncached_devices); 2041 2042 if (timeout < 0 || stopped) 2043 break; 2044 2045 prepare_to_wait(&unregister_wait, &wait, 2046 TASK_UNINTERRUPTIBLE); 2047 2048 mutex_unlock(&bch_register_lock); 2049 schedule_timeout(timeout); 2050 mutex_lock(&bch_register_lock); 2051 } 2052 2053 finish_wait(&unregister_wait, &wait); 2054 2055 if (stopped) 2056 pr_info("All devices stopped"); 2057 else 2058 pr_notice("Timeout waiting for devices to be closed"); 2059 out: 2060 mutex_unlock(&bch_register_lock); 2061 } 2062 2063 return NOTIFY_DONE; 2064 } 2065 2066 static struct notifier_block reboot = { 2067 .notifier_call = bcache_reboot, 2068 .priority = INT_MAX, /* before any real devices */ 2069 }; 2070 2071 static void bcache_exit(void) 2072 { 2073 bch_debug_exit(); 2074 bch_request_exit(); 2075 if (bcache_kobj) 2076 kobject_put(bcache_kobj); 2077 if (bcache_wq) 2078 destroy_workqueue(bcache_wq); 2079 if (bcache_major) 2080 unregister_blkdev(bcache_major, "bcache"); 2081 unregister_reboot_notifier(&reboot); 2082 } 2083 2084 static int __init bcache_init(void) 2085 { 2086 static const struct attribute *files[] = { 2087 &ksysfs_register.attr, 2088 &ksysfs_register_quiet.attr, 2089 NULL 2090 }; 2091 2092 mutex_init(&bch_register_lock); 2093 init_waitqueue_head(&unregister_wait); 2094 register_reboot_notifier(&reboot); 2095 closure_debug_init(); 2096 2097 bcache_major = register_blkdev(0, "bcache"); 2098 if (bcache_major < 0) { 2099 unregister_reboot_notifier(&reboot); 2100 return bcache_major; 2101 } 2102 2103 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) || 2104 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || 2105 sysfs_create_files(bcache_kobj, files) || 2106 bch_request_init() || 2107 bch_debug_init(bcache_kobj)) 2108 goto err; 2109 2110 return 0; 2111 err: 2112 bcache_exit(); 2113 return -ENOMEM; 2114 } 2115 2116 module_exit(bcache_exit); 2117 module_init(bcache_init); 2118