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