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 /* is_read = 0 */ 278 bch_count_io_errors(ca, bio->bi_status, 0, 279 "writing superblock"); 280 closure_put(&ca->set->sb_write); 281 } 282 283 static void bcache_write_super_unlock(struct closure *cl) 284 { 285 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 286 287 up(&c->sb_write_mutex); 288 } 289 290 void bcache_write_super(struct cache_set *c) 291 { 292 struct closure *cl = &c->sb_write; 293 struct cache *ca; 294 unsigned i; 295 296 down(&c->sb_write_mutex); 297 closure_init(cl, &c->cl); 298 299 c->sb.seq++; 300 301 for_each_cache(ca, c, i) { 302 struct bio *bio = &ca->sb_bio; 303 304 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 305 ca->sb.seq = c->sb.seq; 306 ca->sb.last_mount = c->sb.last_mount; 307 308 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 309 310 bio_reset(bio); 311 bio_set_dev(bio, ca->bdev); 312 bio->bi_end_io = write_super_endio; 313 bio->bi_private = ca; 314 315 closure_get(cl); 316 __write_super(&ca->sb, bio); 317 } 318 319 closure_return_with_destructor(cl, bcache_write_super_unlock); 320 } 321 322 /* UUID io */ 323 324 static void uuid_endio(struct bio *bio) 325 { 326 struct closure *cl = bio->bi_private; 327 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 328 329 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 330 bch_bbio_free(bio, c); 331 closure_put(cl); 332 } 333 334 static void uuid_io_unlock(struct closure *cl) 335 { 336 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 337 338 up(&c->uuid_write_mutex); 339 } 340 341 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 342 struct bkey *k, struct closure *parent) 343 { 344 struct closure *cl = &c->uuid_write; 345 struct uuid_entry *u; 346 unsigned i; 347 char buf[80]; 348 349 BUG_ON(!parent); 350 down(&c->uuid_write_mutex); 351 closure_init(cl, parent); 352 353 for (i = 0; i < KEY_PTRS(k); i++) { 354 struct bio *bio = bch_bbio_alloc(c); 355 356 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 357 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 358 359 bio->bi_end_io = uuid_endio; 360 bio->bi_private = cl; 361 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 362 bch_bio_map(bio, c->uuids); 363 364 bch_submit_bbio(bio, c, k, i); 365 366 if (op != REQ_OP_WRITE) 367 break; 368 } 369 370 bch_extent_to_text(buf, sizeof(buf), k); 371 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 372 373 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 374 if (!bch_is_zero(u->uuid, 16)) 375 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 376 u - c->uuids, u->uuid, u->label, 377 u->first_reg, u->last_reg, u->invalidated); 378 379 closure_return_with_destructor(cl, uuid_io_unlock); 380 } 381 382 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 383 { 384 struct bkey *k = &j->uuid_bucket; 385 386 if (__bch_btree_ptr_invalid(c, k)) 387 return "bad uuid pointer"; 388 389 bkey_copy(&c->uuid_bucket, k); 390 uuid_io(c, REQ_OP_READ, 0, k, cl); 391 392 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 393 struct uuid_entry_v0 *u0 = (void *) c->uuids; 394 struct uuid_entry *u1 = (void *) c->uuids; 395 int i; 396 397 closure_sync(cl); 398 399 /* 400 * Since the new uuid entry is bigger than the old, we have to 401 * convert starting at the highest memory address and work down 402 * in order to do it in place 403 */ 404 405 for (i = c->nr_uuids - 1; 406 i >= 0; 407 --i) { 408 memcpy(u1[i].uuid, u0[i].uuid, 16); 409 memcpy(u1[i].label, u0[i].label, 32); 410 411 u1[i].first_reg = u0[i].first_reg; 412 u1[i].last_reg = u0[i].last_reg; 413 u1[i].invalidated = u0[i].invalidated; 414 415 u1[i].flags = 0; 416 u1[i].sectors = 0; 417 } 418 } 419 420 return NULL; 421 } 422 423 static int __uuid_write(struct cache_set *c) 424 { 425 BKEY_PADDED(key) k; 426 struct closure cl; 427 closure_init_stack(&cl); 428 429 lockdep_assert_held(&bch_register_lock); 430 431 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 432 return 1; 433 434 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 435 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 436 closure_sync(&cl); 437 438 bkey_copy(&c->uuid_bucket, &k.key); 439 bkey_put(c, &k.key); 440 return 0; 441 } 442 443 int bch_uuid_write(struct cache_set *c) 444 { 445 int ret = __uuid_write(c); 446 447 if (!ret) 448 bch_journal_meta(c, NULL); 449 450 return ret; 451 } 452 453 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 454 { 455 struct uuid_entry *u; 456 457 for (u = c->uuids; 458 u < c->uuids + c->nr_uuids; u++) 459 if (!memcmp(u->uuid, uuid, 16)) 460 return u; 461 462 return NULL; 463 } 464 465 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 466 { 467 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 468 return uuid_find(c, zero_uuid); 469 } 470 471 /* 472 * Bucket priorities/gens: 473 * 474 * For each bucket, we store on disk its 475 * 8 bit gen 476 * 16 bit priority 477 * 478 * See alloc.c for an explanation of the gen. The priority is used to implement 479 * lru (and in the future other) cache replacement policies; for most purposes 480 * it's just an opaque integer. 481 * 482 * The gens and the priorities don't have a whole lot to do with each other, and 483 * it's actually the gens that must be written out at specific times - it's no 484 * big deal if the priorities don't get written, if we lose them we just reuse 485 * buckets in suboptimal order. 486 * 487 * On disk they're stored in a packed array, and in as many buckets are required 488 * to fit them all. The buckets we use to store them form a list; the journal 489 * header points to the first bucket, the first bucket points to the second 490 * bucket, et cetera. 491 * 492 * This code is used by the allocation code; periodically (whenever it runs out 493 * of buckets to allocate from) the allocation code will invalidate some 494 * buckets, but it can't use those buckets until their new gens are safely on 495 * disk. 496 */ 497 498 static void prio_endio(struct bio *bio) 499 { 500 struct cache *ca = bio->bi_private; 501 502 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 503 bch_bbio_free(bio, ca->set); 504 closure_put(&ca->prio); 505 } 506 507 static void prio_io(struct cache *ca, uint64_t bucket, int op, 508 unsigned long op_flags) 509 { 510 struct closure *cl = &ca->prio; 511 struct bio *bio = bch_bbio_alloc(ca->set); 512 513 closure_init_stack(cl); 514 515 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 516 bio_set_dev(bio, ca->bdev); 517 bio->bi_iter.bi_size = bucket_bytes(ca); 518 519 bio->bi_end_io = prio_endio; 520 bio->bi_private = ca; 521 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 522 bch_bio_map(bio, ca->disk_buckets); 523 524 closure_bio_submit(bio, &ca->prio); 525 closure_sync(cl); 526 } 527 528 void bch_prio_write(struct cache *ca) 529 { 530 int i; 531 struct bucket *b; 532 struct closure cl; 533 534 closure_init_stack(&cl); 535 536 lockdep_assert_held(&ca->set->bucket_lock); 537 538 ca->disk_buckets->seq++; 539 540 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 541 &ca->meta_sectors_written); 542 543 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 544 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 545 546 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 547 long bucket; 548 struct prio_set *p = ca->disk_buckets; 549 struct bucket_disk *d = p->data; 550 struct bucket_disk *end = d + prios_per_bucket(ca); 551 552 for (b = ca->buckets + i * prios_per_bucket(ca); 553 b < ca->buckets + ca->sb.nbuckets && d < end; 554 b++, d++) { 555 d->prio = cpu_to_le16(b->prio); 556 d->gen = b->gen; 557 } 558 559 p->next_bucket = ca->prio_buckets[i + 1]; 560 p->magic = pset_magic(&ca->sb); 561 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 562 563 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 564 BUG_ON(bucket == -1); 565 566 mutex_unlock(&ca->set->bucket_lock); 567 prio_io(ca, bucket, REQ_OP_WRITE, 0); 568 mutex_lock(&ca->set->bucket_lock); 569 570 ca->prio_buckets[i] = bucket; 571 atomic_dec_bug(&ca->buckets[bucket].pin); 572 } 573 574 mutex_unlock(&ca->set->bucket_lock); 575 576 bch_journal_meta(ca->set, &cl); 577 closure_sync(&cl); 578 579 mutex_lock(&ca->set->bucket_lock); 580 581 /* 582 * Don't want the old priorities to get garbage collected until after we 583 * finish writing the new ones, and they're journalled 584 */ 585 for (i = 0; i < prio_buckets(ca); i++) { 586 if (ca->prio_last_buckets[i]) 587 __bch_bucket_free(ca, 588 &ca->buckets[ca->prio_last_buckets[i]]); 589 590 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 591 } 592 } 593 594 static void prio_read(struct cache *ca, uint64_t bucket) 595 { 596 struct prio_set *p = ca->disk_buckets; 597 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 598 struct bucket *b; 599 unsigned bucket_nr = 0; 600 601 for (b = ca->buckets; 602 b < ca->buckets + ca->sb.nbuckets; 603 b++, d++) { 604 if (d == end) { 605 ca->prio_buckets[bucket_nr] = bucket; 606 ca->prio_last_buckets[bucket_nr] = bucket; 607 bucket_nr++; 608 609 prio_io(ca, bucket, REQ_OP_READ, 0); 610 611 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 612 pr_warn("bad csum reading priorities"); 613 614 if (p->magic != pset_magic(&ca->sb)) 615 pr_warn("bad magic reading priorities"); 616 617 bucket = p->next_bucket; 618 d = p->data; 619 } 620 621 b->prio = le16_to_cpu(d->prio); 622 b->gen = b->last_gc = d->gen; 623 } 624 } 625 626 /* Bcache device */ 627 628 static int open_dev(struct block_device *b, fmode_t mode) 629 { 630 struct bcache_device *d = b->bd_disk->private_data; 631 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 632 return -ENXIO; 633 634 closure_get(&d->cl); 635 return 0; 636 } 637 638 static void release_dev(struct gendisk *b, fmode_t mode) 639 { 640 struct bcache_device *d = b->private_data; 641 closure_put(&d->cl); 642 } 643 644 static int ioctl_dev(struct block_device *b, fmode_t mode, 645 unsigned int cmd, unsigned long arg) 646 { 647 struct bcache_device *d = b->bd_disk->private_data; 648 return d->ioctl(d, mode, cmd, arg); 649 } 650 651 static const struct block_device_operations bcache_ops = { 652 .open = open_dev, 653 .release = release_dev, 654 .ioctl = ioctl_dev, 655 .owner = THIS_MODULE, 656 }; 657 658 void bcache_device_stop(struct bcache_device *d) 659 { 660 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 661 closure_queue(&d->cl); 662 } 663 664 static void bcache_device_unlink(struct bcache_device *d) 665 { 666 lockdep_assert_held(&bch_register_lock); 667 668 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 669 unsigned i; 670 struct cache *ca; 671 672 sysfs_remove_link(&d->c->kobj, d->name); 673 sysfs_remove_link(&d->kobj, "cache"); 674 675 for_each_cache(ca, d->c, i) 676 bd_unlink_disk_holder(ca->bdev, d->disk); 677 } 678 } 679 680 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 681 const char *name) 682 { 683 unsigned i; 684 struct cache *ca; 685 686 for_each_cache(ca, d->c, i) 687 bd_link_disk_holder(ca->bdev, d->disk); 688 689 snprintf(d->name, BCACHEDEVNAME_SIZE, 690 "%s%u", name, d->id); 691 692 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 693 sysfs_create_link(&c->kobj, &d->kobj, d->name), 694 "Couldn't create device <-> cache set symlinks"); 695 696 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 697 } 698 699 static void bcache_device_detach(struct bcache_device *d) 700 { 701 lockdep_assert_held(&bch_register_lock); 702 703 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 704 struct uuid_entry *u = d->c->uuids + d->id; 705 706 SET_UUID_FLASH_ONLY(u, 0); 707 memcpy(u->uuid, invalid_uuid, 16); 708 u->invalidated = cpu_to_le32(get_seconds()); 709 bch_uuid_write(d->c); 710 } 711 712 bcache_device_unlink(d); 713 714 d->c->devices[d->id] = NULL; 715 closure_put(&d->c->caching); 716 d->c = NULL; 717 } 718 719 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 720 unsigned id) 721 { 722 d->id = id; 723 d->c = c; 724 c->devices[id] = d; 725 726 if (id >= c->devices_max_used) 727 c->devices_max_used = id + 1; 728 729 closure_get(&c->caching); 730 } 731 732 static inline int first_minor_to_idx(int first_minor) 733 { 734 return (first_minor/BCACHE_MINORS); 735 } 736 737 static inline int idx_to_first_minor(int idx) 738 { 739 return (idx * BCACHE_MINORS); 740 } 741 742 static void bcache_device_free(struct bcache_device *d) 743 { 744 lockdep_assert_held(&bch_register_lock); 745 746 pr_info("%s stopped", d->disk->disk_name); 747 748 if (d->c) 749 bcache_device_detach(d); 750 if (d->disk && d->disk->flags & GENHD_FL_UP) 751 del_gendisk(d->disk); 752 if (d->disk && d->disk->queue) 753 blk_cleanup_queue(d->disk->queue); 754 if (d->disk) { 755 ida_simple_remove(&bcache_device_idx, 756 first_minor_to_idx(d->disk->first_minor)); 757 put_disk(d->disk); 758 } 759 760 if (d->bio_split) 761 bioset_free(d->bio_split); 762 kvfree(d->full_dirty_stripes); 763 kvfree(d->stripe_sectors_dirty); 764 765 closure_debug_destroy(&d->cl); 766 } 767 768 static int bcache_device_init(struct bcache_device *d, unsigned block_size, 769 sector_t sectors) 770 { 771 struct request_queue *q; 772 size_t n; 773 int idx; 774 775 if (!d->stripe_size) 776 d->stripe_size = 1 << 31; 777 778 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 779 780 if (!d->nr_stripes || 781 d->nr_stripes > INT_MAX || 782 d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) { 783 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 784 (unsigned)d->nr_stripes); 785 return -ENOMEM; 786 } 787 788 n = d->nr_stripes * sizeof(atomic_t); 789 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 790 if (!d->stripe_sectors_dirty) 791 return -ENOMEM; 792 793 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 794 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 795 if (!d->full_dirty_stripes) 796 return -ENOMEM; 797 798 idx = ida_simple_get(&bcache_device_idx, 0, 799 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 800 if (idx < 0) 801 return idx; 802 803 if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio), 804 BIOSET_NEED_BVECS | 805 BIOSET_NEED_RESCUER)) || 806 !(d->disk = alloc_disk(BCACHE_MINORS))) { 807 ida_simple_remove(&bcache_device_idx, idx); 808 return -ENOMEM; 809 } 810 811 set_capacity(d->disk, sectors); 812 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 813 814 d->disk->major = bcache_major; 815 d->disk->first_minor = idx_to_first_minor(idx); 816 d->disk->fops = &bcache_ops; 817 d->disk->private_data = d; 818 819 q = blk_alloc_queue(GFP_KERNEL); 820 if (!q) 821 return -ENOMEM; 822 823 blk_queue_make_request(q, NULL); 824 d->disk->queue = q; 825 q->queuedata = d; 826 q->backing_dev_info->congested_data = d; 827 q->limits.max_hw_sectors = UINT_MAX; 828 q->limits.max_sectors = UINT_MAX; 829 q->limits.max_segment_size = UINT_MAX; 830 q->limits.max_segments = BIO_MAX_PAGES; 831 blk_queue_max_discard_sectors(q, UINT_MAX); 832 q->limits.discard_granularity = 512; 833 q->limits.io_min = block_size; 834 q->limits.logical_block_size = block_size; 835 q->limits.physical_block_size = block_size; 836 set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags); 837 clear_bit(QUEUE_FLAG_ADD_RANDOM, &d->disk->queue->queue_flags); 838 set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags); 839 840 blk_queue_write_cache(q, true, true); 841 842 return 0; 843 } 844 845 /* Cached device */ 846 847 static void calc_cached_dev_sectors(struct cache_set *c) 848 { 849 uint64_t sectors = 0; 850 struct cached_dev *dc; 851 852 list_for_each_entry(dc, &c->cached_devs, list) 853 sectors += bdev_sectors(dc->bdev); 854 855 c->cached_dev_sectors = sectors; 856 } 857 858 void bch_cached_dev_run(struct cached_dev *dc) 859 { 860 struct bcache_device *d = &dc->disk; 861 char buf[SB_LABEL_SIZE + 1]; 862 char *env[] = { 863 "DRIVER=bcache", 864 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 865 NULL, 866 NULL, 867 }; 868 869 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 870 buf[SB_LABEL_SIZE] = '\0'; 871 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 872 873 if (atomic_xchg(&dc->running, 1)) { 874 kfree(env[1]); 875 kfree(env[2]); 876 return; 877 } 878 879 if (!d->c && 880 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 881 struct closure cl; 882 closure_init_stack(&cl); 883 884 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 885 bch_write_bdev_super(dc, &cl); 886 closure_sync(&cl); 887 } 888 889 add_disk(d->disk); 890 bd_link_disk_holder(dc->bdev, dc->disk.disk); 891 /* won't show up in the uevent file, use udevadm monitor -e instead 892 * only class / kset properties are persistent */ 893 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 894 kfree(env[1]); 895 kfree(env[2]); 896 897 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 898 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 899 pr_debug("error creating sysfs link"); 900 } 901 902 static void cached_dev_detach_finish(struct work_struct *w) 903 { 904 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 905 char buf[BDEVNAME_SIZE]; 906 struct closure cl; 907 closure_init_stack(&cl); 908 909 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 910 BUG_ON(refcount_read(&dc->count)); 911 912 mutex_lock(&bch_register_lock); 913 914 cancel_delayed_work_sync(&dc->writeback_rate_update); 915 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 916 kthread_stop(dc->writeback_thread); 917 dc->writeback_thread = NULL; 918 } 919 920 memset(&dc->sb.set_uuid, 0, 16); 921 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 922 923 bch_write_bdev_super(dc, &cl); 924 closure_sync(&cl); 925 926 bcache_device_detach(&dc->disk); 927 list_move(&dc->list, &uncached_devices); 928 929 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 930 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 931 932 mutex_unlock(&bch_register_lock); 933 934 pr_info("Caching disabled for %s", bdevname(dc->bdev, buf)); 935 936 /* Drop ref we took in cached_dev_detach() */ 937 closure_put(&dc->disk.cl); 938 } 939 940 void bch_cached_dev_detach(struct cached_dev *dc) 941 { 942 lockdep_assert_held(&bch_register_lock); 943 944 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 945 return; 946 947 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 948 return; 949 950 /* 951 * Block the device from being closed and freed until we're finished 952 * detaching 953 */ 954 closure_get(&dc->disk.cl); 955 956 bch_writeback_queue(dc); 957 cached_dev_put(dc); 958 } 959 960 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c) 961 { 962 uint32_t rtime = cpu_to_le32(get_seconds()); 963 struct uuid_entry *u; 964 char buf[BDEVNAME_SIZE]; 965 966 bdevname(dc->bdev, buf); 967 968 if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)) 969 return -ENOENT; 970 971 if (dc->disk.c) { 972 pr_err("Can't attach %s: already attached", buf); 973 return -EINVAL; 974 } 975 976 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 977 pr_err("Can't attach %s: shutting down", buf); 978 return -EINVAL; 979 } 980 981 if (dc->sb.block_size < c->sb.block_size) { 982 /* Will die */ 983 pr_err("Couldn't attach %s: block size less than set's block size", 984 buf); 985 return -EINVAL; 986 } 987 988 u = uuid_find(c, dc->sb.uuid); 989 990 if (u && 991 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 992 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 993 memcpy(u->uuid, invalid_uuid, 16); 994 u->invalidated = cpu_to_le32(get_seconds()); 995 u = NULL; 996 } 997 998 if (!u) { 999 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1000 pr_err("Couldn't find uuid for %s in set", buf); 1001 return -ENOENT; 1002 } 1003 1004 u = uuid_find_empty(c); 1005 if (!u) { 1006 pr_err("Not caching %s, no room for UUID", buf); 1007 return -EINVAL; 1008 } 1009 } 1010 1011 /* Deadlocks since we're called via sysfs... 1012 sysfs_remove_file(&dc->kobj, &sysfs_attach); 1013 */ 1014 1015 if (bch_is_zero(u->uuid, 16)) { 1016 struct closure cl; 1017 closure_init_stack(&cl); 1018 1019 memcpy(u->uuid, dc->sb.uuid, 16); 1020 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1021 u->first_reg = u->last_reg = rtime; 1022 bch_uuid_write(c); 1023 1024 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1025 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1026 1027 bch_write_bdev_super(dc, &cl); 1028 closure_sync(&cl); 1029 } else { 1030 u->last_reg = rtime; 1031 bch_uuid_write(c); 1032 } 1033 1034 bcache_device_attach(&dc->disk, c, u - c->uuids); 1035 list_move(&dc->list, &c->cached_devs); 1036 calc_cached_dev_sectors(c); 1037 1038 smp_wmb(); 1039 /* 1040 * dc->c must be set before dc->count != 0 - paired with the mb in 1041 * cached_dev_get() 1042 */ 1043 refcount_set(&dc->count, 1); 1044 1045 /* Block writeback thread, but spawn it */ 1046 down_write(&dc->writeback_lock); 1047 if (bch_cached_dev_writeback_start(dc)) { 1048 up_write(&dc->writeback_lock); 1049 return -ENOMEM; 1050 } 1051 1052 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1053 bch_sectors_dirty_init(&dc->disk); 1054 atomic_set(&dc->has_dirty, 1); 1055 refcount_inc(&dc->count); 1056 bch_writeback_queue(dc); 1057 } 1058 1059 bch_cached_dev_run(dc); 1060 bcache_device_link(&dc->disk, c, "bdev"); 1061 1062 /* Allow the writeback thread to proceed */ 1063 up_write(&dc->writeback_lock); 1064 1065 pr_info("Caching %s as %s on set %pU", 1066 bdevname(dc->bdev, buf), dc->disk.disk->disk_name, 1067 dc->disk.c->sb.set_uuid); 1068 return 0; 1069 } 1070 1071 void bch_cached_dev_release(struct kobject *kobj) 1072 { 1073 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1074 disk.kobj); 1075 kfree(dc); 1076 module_put(THIS_MODULE); 1077 } 1078 1079 static void cached_dev_free(struct closure *cl) 1080 { 1081 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1082 1083 cancel_delayed_work_sync(&dc->writeback_rate_update); 1084 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1085 kthread_stop(dc->writeback_thread); 1086 if (dc->writeback_write_wq) 1087 destroy_workqueue(dc->writeback_write_wq); 1088 1089 mutex_lock(&bch_register_lock); 1090 1091 if (atomic_read(&dc->running)) 1092 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1093 bcache_device_free(&dc->disk); 1094 list_del(&dc->list); 1095 1096 mutex_unlock(&bch_register_lock); 1097 1098 if (!IS_ERR_OR_NULL(dc->bdev)) 1099 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1100 1101 wake_up(&unregister_wait); 1102 1103 kobject_put(&dc->disk.kobj); 1104 } 1105 1106 static void cached_dev_flush(struct closure *cl) 1107 { 1108 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1109 struct bcache_device *d = &dc->disk; 1110 1111 mutex_lock(&bch_register_lock); 1112 bcache_device_unlink(d); 1113 mutex_unlock(&bch_register_lock); 1114 1115 bch_cache_accounting_destroy(&dc->accounting); 1116 kobject_del(&d->kobj); 1117 1118 continue_at(cl, cached_dev_free, system_wq); 1119 } 1120 1121 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1122 { 1123 int ret; 1124 struct io *io; 1125 struct request_queue *q = bdev_get_queue(dc->bdev); 1126 1127 __module_get(THIS_MODULE); 1128 INIT_LIST_HEAD(&dc->list); 1129 closure_init(&dc->disk.cl, NULL); 1130 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1131 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1132 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1133 sema_init(&dc->sb_write_mutex, 1); 1134 INIT_LIST_HEAD(&dc->io_lru); 1135 spin_lock_init(&dc->io_lock); 1136 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1137 1138 dc->sequential_cutoff = 4 << 20; 1139 1140 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1141 list_add(&io->lru, &dc->io_lru); 1142 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1143 } 1144 1145 dc->disk.stripe_size = q->limits.io_opt >> 9; 1146 1147 if (dc->disk.stripe_size) 1148 dc->partial_stripes_expensive = 1149 q->limits.raid_partial_stripes_expensive; 1150 1151 ret = bcache_device_init(&dc->disk, block_size, 1152 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1153 if (ret) 1154 return ret; 1155 1156 dc->disk.disk->queue->backing_dev_info->ra_pages = 1157 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1158 q->backing_dev_info->ra_pages); 1159 1160 bch_cached_dev_request_init(dc); 1161 bch_cached_dev_writeback_init(dc); 1162 return 0; 1163 } 1164 1165 /* Cached device - bcache superblock */ 1166 1167 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1168 struct block_device *bdev, 1169 struct cached_dev *dc) 1170 { 1171 char name[BDEVNAME_SIZE]; 1172 const char *err = "cannot allocate memory"; 1173 struct cache_set *c; 1174 1175 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1176 dc->bdev = bdev; 1177 dc->bdev->bd_holder = dc; 1178 1179 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1180 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1181 get_page(sb_page); 1182 1183 if (cached_dev_init(dc, sb->block_size << 9)) 1184 goto err; 1185 1186 err = "error creating kobject"; 1187 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1188 "bcache")) 1189 goto err; 1190 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1191 goto err; 1192 1193 pr_info("registered backing device %s", bdevname(bdev, name)); 1194 1195 list_add(&dc->list, &uncached_devices); 1196 list_for_each_entry(c, &bch_cache_sets, list) 1197 bch_cached_dev_attach(dc, c); 1198 1199 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1200 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1201 bch_cached_dev_run(dc); 1202 1203 return; 1204 err: 1205 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1206 bcache_device_stop(&dc->disk); 1207 } 1208 1209 /* Flash only volumes */ 1210 1211 void bch_flash_dev_release(struct kobject *kobj) 1212 { 1213 struct bcache_device *d = container_of(kobj, struct bcache_device, 1214 kobj); 1215 kfree(d); 1216 } 1217 1218 static void flash_dev_free(struct closure *cl) 1219 { 1220 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1221 mutex_lock(&bch_register_lock); 1222 bcache_device_free(d); 1223 mutex_unlock(&bch_register_lock); 1224 kobject_put(&d->kobj); 1225 } 1226 1227 static void flash_dev_flush(struct closure *cl) 1228 { 1229 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1230 1231 mutex_lock(&bch_register_lock); 1232 bcache_device_unlink(d); 1233 mutex_unlock(&bch_register_lock); 1234 kobject_del(&d->kobj); 1235 continue_at(cl, flash_dev_free, system_wq); 1236 } 1237 1238 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1239 { 1240 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1241 GFP_KERNEL); 1242 if (!d) 1243 return -ENOMEM; 1244 1245 closure_init(&d->cl, NULL); 1246 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1247 1248 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1249 1250 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1251 goto err; 1252 1253 bcache_device_attach(d, c, u - c->uuids); 1254 bch_sectors_dirty_init(d); 1255 bch_flash_dev_request_init(d); 1256 add_disk(d->disk); 1257 1258 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1259 goto err; 1260 1261 bcache_device_link(d, c, "volume"); 1262 1263 return 0; 1264 err: 1265 kobject_put(&d->kobj); 1266 return -ENOMEM; 1267 } 1268 1269 static int flash_devs_run(struct cache_set *c) 1270 { 1271 int ret = 0; 1272 struct uuid_entry *u; 1273 1274 for (u = c->uuids; 1275 u < c->uuids + c->devices_max_used && !ret; 1276 u++) 1277 if (UUID_FLASH_ONLY(u)) 1278 ret = flash_dev_run(c, u); 1279 1280 return ret; 1281 } 1282 1283 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1284 { 1285 struct uuid_entry *u; 1286 1287 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1288 return -EINTR; 1289 1290 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1291 return -EPERM; 1292 1293 u = uuid_find_empty(c); 1294 if (!u) { 1295 pr_err("Can't create volume, no room for UUID"); 1296 return -EINVAL; 1297 } 1298 1299 get_random_bytes(u->uuid, 16); 1300 memset(u->label, 0, 32); 1301 u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); 1302 1303 SET_UUID_FLASH_ONLY(u, 1); 1304 u->sectors = size >> 9; 1305 1306 bch_uuid_write(c); 1307 1308 return flash_dev_run(c, u); 1309 } 1310 1311 /* Cache set */ 1312 1313 __printf(2, 3) 1314 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1315 { 1316 va_list args; 1317 1318 if (c->on_error != ON_ERROR_PANIC && 1319 test_bit(CACHE_SET_STOPPING, &c->flags)) 1320 return false; 1321 1322 /* XXX: we can be called from atomic context 1323 acquire_console_sem(); 1324 */ 1325 1326 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1327 1328 va_start(args, fmt); 1329 vprintk(fmt, args); 1330 va_end(args); 1331 1332 printk(", disabling caching\n"); 1333 1334 if (c->on_error == ON_ERROR_PANIC) 1335 panic("panic forced after error\n"); 1336 1337 bch_cache_set_unregister(c); 1338 return true; 1339 } 1340 1341 void bch_cache_set_release(struct kobject *kobj) 1342 { 1343 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1344 kfree(c); 1345 module_put(THIS_MODULE); 1346 } 1347 1348 static void cache_set_free(struct closure *cl) 1349 { 1350 struct cache_set *c = container_of(cl, struct cache_set, cl); 1351 struct cache *ca; 1352 unsigned i; 1353 1354 if (!IS_ERR_OR_NULL(c->debug)) 1355 debugfs_remove(c->debug); 1356 1357 bch_open_buckets_free(c); 1358 bch_btree_cache_free(c); 1359 bch_journal_free(c); 1360 1361 for_each_cache(ca, c, i) 1362 if (ca) { 1363 ca->set = NULL; 1364 c->cache[ca->sb.nr_this_dev] = NULL; 1365 kobject_put(&ca->kobj); 1366 } 1367 1368 bch_bset_sort_state_free(&c->sort); 1369 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1370 1371 if (c->moving_gc_wq) 1372 destroy_workqueue(c->moving_gc_wq); 1373 if (c->bio_split) 1374 bioset_free(c->bio_split); 1375 if (c->fill_iter) 1376 mempool_destroy(c->fill_iter); 1377 if (c->bio_meta) 1378 mempool_destroy(c->bio_meta); 1379 if (c->search) 1380 mempool_destroy(c->search); 1381 kfree(c->devices); 1382 1383 mutex_lock(&bch_register_lock); 1384 list_del(&c->list); 1385 mutex_unlock(&bch_register_lock); 1386 1387 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1388 wake_up(&unregister_wait); 1389 1390 closure_debug_destroy(&c->cl); 1391 kobject_put(&c->kobj); 1392 } 1393 1394 static void cache_set_flush(struct closure *cl) 1395 { 1396 struct cache_set *c = container_of(cl, struct cache_set, caching); 1397 struct cache *ca; 1398 struct btree *b; 1399 unsigned i; 1400 1401 bch_cache_accounting_destroy(&c->accounting); 1402 1403 kobject_put(&c->internal); 1404 kobject_del(&c->kobj); 1405 1406 if (c->gc_thread) 1407 kthread_stop(c->gc_thread); 1408 1409 if (!IS_ERR_OR_NULL(c->root)) 1410 list_add(&c->root->list, &c->btree_cache); 1411 1412 /* Should skip this if we're unregistering because of an error */ 1413 list_for_each_entry(b, &c->btree_cache, list) { 1414 mutex_lock(&b->write_lock); 1415 if (btree_node_dirty(b)) 1416 __bch_btree_node_write(b, NULL); 1417 mutex_unlock(&b->write_lock); 1418 } 1419 1420 for_each_cache(ca, c, i) 1421 if (ca->alloc_thread) 1422 kthread_stop(ca->alloc_thread); 1423 1424 if (c->journal.cur) { 1425 cancel_delayed_work_sync(&c->journal.work); 1426 /* flush last journal entry if needed */ 1427 c->journal.work.work.func(&c->journal.work.work); 1428 } 1429 1430 closure_return(cl); 1431 } 1432 1433 static void __cache_set_unregister(struct closure *cl) 1434 { 1435 struct cache_set *c = container_of(cl, struct cache_set, caching); 1436 struct cached_dev *dc; 1437 size_t i; 1438 1439 mutex_lock(&bch_register_lock); 1440 1441 for (i = 0; i < c->devices_max_used; i++) 1442 if (c->devices[i]) { 1443 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1444 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1445 dc = container_of(c->devices[i], 1446 struct cached_dev, disk); 1447 bch_cached_dev_detach(dc); 1448 } else { 1449 bcache_device_stop(c->devices[i]); 1450 } 1451 } 1452 1453 mutex_unlock(&bch_register_lock); 1454 1455 continue_at(cl, cache_set_flush, system_wq); 1456 } 1457 1458 void bch_cache_set_stop(struct cache_set *c) 1459 { 1460 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1461 closure_queue(&c->caching); 1462 } 1463 1464 void bch_cache_set_unregister(struct cache_set *c) 1465 { 1466 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1467 bch_cache_set_stop(c); 1468 } 1469 1470 #define alloc_bucket_pages(gfp, c) \ 1471 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1472 1473 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1474 { 1475 int iter_size; 1476 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1477 if (!c) 1478 return NULL; 1479 1480 __module_get(THIS_MODULE); 1481 closure_init(&c->cl, NULL); 1482 set_closure_fn(&c->cl, cache_set_free, system_wq); 1483 1484 closure_init(&c->caching, &c->cl); 1485 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1486 1487 /* Maybe create continue_at_noreturn() and use it here? */ 1488 closure_set_stopped(&c->cl); 1489 closure_put(&c->cl); 1490 1491 kobject_init(&c->kobj, &bch_cache_set_ktype); 1492 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1493 1494 bch_cache_accounting_init(&c->accounting, &c->cl); 1495 1496 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1497 c->sb.block_size = sb->block_size; 1498 c->sb.bucket_size = sb->bucket_size; 1499 c->sb.nr_in_set = sb->nr_in_set; 1500 c->sb.last_mount = sb->last_mount; 1501 c->bucket_bits = ilog2(sb->bucket_size); 1502 c->block_bits = ilog2(sb->block_size); 1503 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1504 c->devices_max_used = 0; 1505 c->btree_pages = bucket_pages(c); 1506 if (c->btree_pages > BTREE_MAX_PAGES) 1507 c->btree_pages = max_t(int, c->btree_pages / 4, 1508 BTREE_MAX_PAGES); 1509 1510 sema_init(&c->sb_write_mutex, 1); 1511 mutex_init(&c->bucket_lock); 1512 init_waitqueue_head(&c->btree_cache_wait); 1513 init_waitqueue_head(&c->bucket_wait); 1514 init_waitqueue_head(&c->gc_wait); 1515 sema_init(&c->uuid_write_mutex, 1); 1516 1517 spin_lock_init(&c->btree_gc_time.lock); 1518 spin_lock_init(&c->btree_split_time.lock); 1519 spin_lock_init(&c->btree_read_time.lock); 1520 1521 bch_moving_init_cache_set(c); 1522 1523 INIT_LIST_HEAD(&c->list); 1524 INIT_LIST_HEAD(&c->cached_devs); 1525 INIT_LIST_HEAD(&c->btree_cache); 1526 INIT_LIST_HEAD(&c->btree_cache_freeable); 1527 INIT_LIST_HEAD(&c->btree_cache_freed); 1528 INIT_LIST_HEAD(&c->data_buckets); 1529 1530 c->search = mempool_create_slab_pool(32, bch_search_cache); 1531 if (!c->search) 1532 goto err; 1533 1534 iter_size = (sb->bucket_size / sb->block_size + 1) * 1535 sizeof(struct btree_iter_set); 1536 1537 if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) || 1538 !(c->bio_meta = mempool_create_kmalloc_pool(2, 1539 sizeof(struct bbio) + sizeof(struct bio_vec) * 1540 bucket_pages(c))) || 1541 !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) || 1542 !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio), 1543 BIOSET_NEED_BVECS | 1544 BIOSET_NEED_RESCUER)) || 1545 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1546 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1547 WQ_MEM_RECLAIM, 0)) || 1548 bch_journal_alloc(c) || 1549 bch_btree_cache_alloc(c) || 1550 bch_open_buckets_alloc(c) || 1551 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1552 goto err; 1553 1554 c->congested_read_threshold_us = 2000; 1555 c->congested_write_threshold_us = 20000; 1556 c->error_limit = 8 << IO_ERROR_SHIFT; 1557 1558 return c; 1559 err: 1560 bch_cache_set_unregister(c); 1561 return NULL; 1562 } 1563 1564 static void run_cache_set(struct cache_set *c) 1565 { 1566 const char *err = "cannot allocate memory"; 1567 struct cached_dev *dc, *t; 1568 struct cache *ca; 1569 struct closure cl; 1570 unsigned i; 1571 1572 closure_init_stack(&cl); 1573 1574 for_each_cache(ca, c, i) 1575 c->nbuckets += ca->sb.nbuckets; 1576 set_gc_sectors(c); 1577 1578 if (CACHE_SYNC(&c->sb)) { 1579 LIST_HEAD(journal); 1580 struct bkey *k; 1581 struct jset *j; 1582 1583 err = "cannot allocate memory for journal"; 1584 if (bch_journal_read(c, &journal)) 1585 goto err; 1586 1587 pr_debug("btree_journal_read() done"); 1588 1589 err = "no journal entries found"; 1590 if (list_empty(&journal)) 1591 goto err; 1592 1593 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1594 1595 err = "IO error reading priorities"; 1596 for_each_cache(ca, c, i) 1597 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1598 1599 /* 1600 * If prio_read() fails it'll call cache_set_error and we'll 1601 * tear everything down right away, but if we perhaps checked 1602 * sooner we could avoid journal replay. 1603 */ 1604 1605 k = &j->btree_root; 1606 1607 err = "bad btree root"; 1608 if (__bch_btree_ptr_invalid(c, k)) 1609 goto err; 1610 1611 err = "error reading btree root"; 1612 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1613 if (IS_ERR_OR_NULL(c->root)) 1614 goto err; 1615 1616 list_del_init(&c->root->list); 1617 rw_unlock(true, c->root); 1618 1619 err = uuid_read(c, j, &cl); 1620 if (err) 1621 goto err; 1622 1623 err = "error in recovery"; 1624 if (bch_btree_check(c)) 1625 goto err; 1626 1627 bch_journal_mark(c, &journal); 1628 bch_initial_gc_finish(c); 1629 pr_debug("btree_check() done"); 1630 1631 /* 1632 * bcache_journal_next() can't happen sooner, or 1633 * btree_gc_finish() will give spurious errors about last_gc > 1634 * gc_gen - this is a hack but oh well. 1635 */ 1636 bch_journal_next(&c->journal); 1637 1638 err = "error starting allocator thread"; 1639 for_each_cache(ca, c, i) 1640 if (bch_cache_allocator_start(ca)) 1641 goto err; 1642 1643 /* 1644 * First place it's safe to allocate: btree_check() and 1645 * btree_gc_finish() have to run before we have buckets to 1646 * allocate, and bch_bucket_alloc_set() might cause a journal 1647 * entry to be written so bcache_journal_next() has to be called 1648 * first. 1649 * 1650 * If the uuids were in the old format we have to rewrite them 1651 * before the next journal entry is written: 1652 */ 1653 if (j->version < BCACHE_JSET_VERSION_UUID) 1654 __uuid_write(c); 1655 1656 bch_journal_replay(c, &journal); 1657 } else { 1658 pr_notice("invalidating existing data"); 1659 1660 for_each_cache(ca, c, i) { 1661 unsigned j; 1662 1663 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1664 2, SB_JOURNAL_BUCKETS); 1665 1666 for (j = 0; j < ca->sb.keys; j++) 1667 ca->sb.d[j] = ca->sb.first_bucket + j; 1668 } 1669 1670 bch_initial_gc_finish(c); 1671 1672 err = "error starting allocator thread"; 1673 for_each_cache(ca, c, i) 1674 if (bch_cache_allocator_start(ca)) 1675 goto err; 1676 1677 mutex_lock(&c->bucket_lock); 1678 for_each_cache(ca, c, i) 1679 bch_prio_write(ca); 1680 mutex_unlock(&c->bucket_lock); 1681 1682 err = "cannot allocate new UUID bucket"; 1683 if (__uuid_write(c)) 1684 goto err; 1685 1686 err = "cannot allocate new btree root"; 1687 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1688 if (IS_ERR_OR_NULL(c->root)) 1689 goto err; 1690 1691 mutex_lock(&c->root->write_lock); 1692 bkey_copy_key(&c->root->key, &MAX_KEY); 1693 bch_btree_node_write(c->root, &cl); 1694 mutex_unlock(&c->root->write_lock); 1695 1696 bch_btree_set_root(c->root); 1697 rw_unlock(true, c->root); 1698 1699 /* 1700 * We don't want to write the first journal entry until 1701 * everything is set up - fortunately journal entries won't be 1702 * written until the SET_CACHE_SYNC() here: 1703 */ 1704 SET_CACHE_SYNC(&c->sb, true); 1705 1706 bch_journal_next(&c->journal); 1707 bch_journal_meta(c, &cl); 1708 } 1709 1710 err = "error starting gc thread"; 1711 if (bch_gc_thread_start(c)) 1712 goto err; 1713 1714 closure_sync(&cl); 1715 c->sb.last_mount = get_seconds(); 1716 bcache_write_super(c); 1717 1718 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1719 bch_cached_dev_attach(dc, c); 1720 1721 flash_devs_run(c); 1722 1723 set_bit(CACHE_SET_RUNNING, &c->flags); 1724 return; 1725 err: 1726 closure_sync(&cl); 1727 /* XXX: test this, it's broken */ 1728 bch_cache_set_error(c, "%s", err); 1729 } 1730 1731 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1732 { 1733 return ca->sb.block_size == c->sb.block_size && 1734 ca->sb.bucket_size == c->sb.bucket_size && 1735 ca->sb.nr_in_set == c->sb.nr_in_set; 1736 } 1737 1738 static const char *register_cache_set(struct cache *ca) 1739 { 1740 char buf[12]; 1741 const char *err = "cannot allocate memory"; 1742 struct cache_set *c; 1743 1744 list_for_each_entry(c, &bch_cache_sets, list) 1745 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1746 if (c->cache[ca->sb.nr_this_dev]) 1747 return "duplicate cache set member"; 1748 1749 if (!can_attach_cache(ca, c)) 1750 return "cache sb does not match set"; 1751 1752 if (!CACHE_SYNC(&ca->sb)) 1753 SET_CACHE_SYNC(&c->sb, false); 1754 1755 goto found; 1756 } 1757 1758 c = bch_cache_set_alloc(&ca->sb); 1759 if (!c) 1760 return err; 1761 1762 err = "error creating kobject"; 1763 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1764 kobject_add(&c->internal, &c->kobj, "internal")) 1765 goto err; 1766 1767 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1768 goto err; 1769 1770 bch_debug_init_cache_set(c); 1771 1772 list_add(&c->list, &bch_cache_sets); 1773 found: 1774 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1775 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1776 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1777 goto err; 1778 1779 if (ca->sb.seq > c->sb.seq) { 1780 c->sb.version = ca->sb.version; 1781 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1782 c->sb.flags = ca->sb.flags; 1783 c->sb.seq = ca->sb.seq; 1784 pr_debug("set version = %llu", c->sb.version); 1785 } 1786 1787 kobject_get(&ca->kobj); 1788 ca->set = c; 1789 ca->set->cache[ca->sb.nr_this_dev] = ca; 1790 c->cache_by_alloc[c->caches_loaded++] = ca; 1791 1792 if (c->caches_loaded == c->sb.nr_in_set) 1793 run_cache_set(c); 1794 1795 return NULL; 1796 err: 1797 bch_cache_set_unregister(c); 1798 return err; 1799 } 1800 1801 /* Cache device */ 1802 1803 void bch_cache_release(struct kobject *kobj) 1804 { 1805 struct cache *ca = container_of(kobj, struct cache, kobj); 1806 unsigned i; 1807 1808 if (ca->set) { 1809 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 1810 ca->set->cache[ca->sb.nr_this_dev] = NULL; 1811 } 1812 1813 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 1814 kfree(ca->prio_buckets); 1815 vfree(ca->buckets); 1816 1817 free_heap(&ca->heap); 1818 free_fifo(&ca->free_inc); 1819 1820 for (i = 0; i < RESERVE_NR; i++) 1821 free_fifo(&ca->free[i]); 1822 1823 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 1824 put_page(bio_first_page_all(&ca->sb_bio)); 1825 1826 if (!IS_ERR_OR_NULL(ca->bdev)) 1827 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1828 1829 kfree(ca); 1830 module_put(THIS_MODULE); 1831 } 1832 1833 static int cache_alloc(struct cache *ca) 1834 { 1835 size_t free; 1836 struct bucket *b; 1837 1838 __module_get(THIS_MODULE); 1839 kobject_init(&ca->kobj, &bch_cache_ktype); 1840 1841 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 1842 1843 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 1844 1845 if (!init_fifo(&ca->free[RESERVE_BTREE], 8, GFP_KERNEL) || 1846 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 1847 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 1848 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 1849 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 1850 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 1851 !(ca->buckets = vzalloc(sizeof(struct bucket) * 1852 ca->sb.nbuckets)) || 1853 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 1854 2, GFP_KERNEL)) || 1855 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 1856 return -ENOMEM; 1857 1858 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 1859 1860 for_each_bucket(b, ca) 1861 atomic_set(&b->pin, 0); 1862 1863 return 0; 1864 } 1865 1866 static int register_cache(struct cache_sb *sb, struct page *sb_page, 1867 struct block_device *bdev, struct cache *ca) 1868 { 1869 char name[BDEVNAME_SIZE]; 1870 const char *err = NULL; /* must be set for any error case */ 1871 int ret = 0; 1872 1873 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 1874 ca->bdev = bdev; 1875 ca->bdev->bd_holder = ca; 1876 1877 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 1878 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 1879 get_page(sb_page); 1880 1881 if (blk_queue_discard(bdev_get_queue(ca->bdev))) 1882 ca->discard = CACHE_DISCARD(&ca->sb); 1883 1884 ret = cache_alloc(ca); 1885 if (ret != 0) { 1886 if (ret == -ENOMEM) 1887 err = "cache_alloc(): -ENOMEM"; 1888 else 1889 err = "cache_alloc(): unknown error"; 1890 goto err; 1891 } 1892 1893 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 1894 err = "error calling kobject_add"; 1895 ret = -ENOMEM; 1896 goto out; 1897 } 1898 1899 mutex_lock(&bch_register_lock); 1900 err = register_cache_set(ca); 1901 mutex_unlock(&bch_register_lock); 1902 1903 if (err) { 1904 ret = -ENODEV; 1905 goto out; 1906 } 1907 1908 pr_info("registered cache device %s", bdevname(bdev, name)); 1909 1910 out: 1911 kobject_put(&ca->kobj); 1912 1913 err: 1914 if (err) 1915 pr_notice("error opening %s: %s", bdevname(bdev, name), err); 1916 1917 return ret; 1918 } 1919 1920 /* Global interfaces/init */ 1921 1922 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 1923 const char *, size_t); 1924 1925 kobj_attribute_write(register, register_bcache); 1926 kobj_attribute_write(register_quiet, register_bcache); 1927 1928 static bool bch_is_open_backing(struct block_device *bdev) { 1929 struct cache_set *c, *tc; 1930 struct cached_dev *dc, *t; 1931 1932 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1933 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 1934 if (dc->bdev == bdev) 1935 return true; 1936 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1937 if (dc->bdev == bdev) 1938 return true; 1939 return false; 1940 } 1941 1942 static bool bch_is_open_cache(struct block_device *bdev) { 1943 struct cache_set *c, *tc; 1944 struct cache *ca; 1945 unsigned i; 1946 1947 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 1948 for_each_cache(ca, c, i) 1949 if (ca->bdev == bdev) 1950 return true; 1951 return false; 1952 } 1953 1954 static bool bch_is_open(struct block_device *bdev) { 1955 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 1956 } 1957 1958 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 1959 const char *buffer, size_t size) 1960 { 1961 ssize_t ret = size; 1962 const char *err = "cannot allocate memory"; 1963 char *path = NULL; 1964 struct cache_sb *sb = NULL; 1965 struct block_device *bdev = NULL; 1966 struct page *sb_page = NULL; 1967 1968 if (!try_module_get(THIS_MODULE)) 1969 return -EBUSY; 1970 1971 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || 1972 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) 1973 goto err; 1974 1975 err = "failed to open device"; 1976 bdev = blkdev_get_by_path(strim(path), 1977 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 1978 sb); 1979 if (IS_ERR(bdev)) { 1980 if (bdev == ERR_PTR(-EBUSY)) { 1981 bdev = lookup_bdev(strim(path)); 1982 mutex_lock(&bch_register_lock); 1983 if (!IS_ERR(bdev) && bch_is_open(bdev)) 1984 err = "device already registered"; 1985 else 1986 err = "device busy"; 1987 mutex_unlock(&bch_register_lock); 1988 if (!IS_ERR(bdev)) 1989 bdput(bdev); 1990 if (attr == &ksysfs_register_quiet) 1991 goto out; 1992 } 1993 goto err; 1994 } 1995 1996 err = "failed to set blocksize"; 1997 if (set_blocksize(bdev, 4096)) 1998 goto err_close; 1999 2000 err = read_super(sb, bdev, &sb_page); 2001 if (err) 2002 goto err_close; 2003 2004 if (SB_IS_BDEV(sb)) { 2005 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2006 if (!dc) 2007 goto err_close; 2008 2009 mutex_lock(&bch_register_lock); 2010 register_bdev(sb, sb_page, bdev, dc); 2011 mutex_unlock(&bch_register_lock); 2012 } else { 2013 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2014 if (!ca) 2015 goto err_close; 2016 2017 if (register_cache(sb, sb_page, bdev, ca) != 0) 2018 goto err_close; 2019 } 2020 out: 2021 if (sb_page) 2022 put_page(sb_page); 2023 kfree(sb); 2024 kfree(path); 2025 module_put(THIS_MODULE); 2026 return ret; 2027 2028 err_close: 2029 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2030 err: 2031 pr_info("error opening %s: %s", path, err); 2032 ret = -EINVAL; 2033 goto out; 2034 } 2035 2036 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2037 { 2038 if (code == SYS_DOWN || 2039 code == SYS_HALT || 2040 code == SYS_POWER_OFF) { 2041 DEFINE_WAIT(wait); 2042 unsigned long start = jiffies; 2043 bool stopped = false; 2044 2045 struct cache_set *c, *tc; 2046 struct cached_dev *dc, *tdc; 2047 2048 mutex_lock(&bch_register_lock); 2049 2050 if (list_empty(&bch_cache_sets) && 2051 list_empty(&uncached_devices)) 2052 goto out; 2053 2054 pr_info("Stopping all devices:"); 2055 2056 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2057 bch_cache_set_stop(c); 2058 2059 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2060 bcache_device_stop(&dc->disk); 2061 2062 /* What's a condition variable? */ 2063 while (1) { 2064 long timeout = start + 2 * HZ - jiffies; 2065 2066 stopped = list_empty(&bch_cache_sets) && 2067 list_empty(&uncached_devices); 2068 2069 if (timeout < 0 || stopped) 2070 break; 2071 2072 prepare_to_wait(&unregister_wait, &wait, 2073 TASK_UNINTERRUPTIBLE); 2074 2075 mutex_unlock(&bch_register_lock); 2076 schedule_timeout(timeout); 2077 mutex_lock(&bch_register_lock); 2078 } 2079 2080 finish_wait(&unregister_wait, &wait); 2081 2082 if (stopped) 2083 pr_info("All devices stopped"); 2084 else 2085 pr_notice("Timeout waiting for devices to be closed"); 2086 out: 2087 mutex_unlock(&bch_register_lock); 2088 } 2089 2090 return NOTIFY_DONE; 2091 } 2092 2093 static struct notifier_block reboot = { 2094 .notifier_call = bcache_reboot, 2095 .priority = INT_MAX, /* before any real devices */ 2096 }; 2097 2098 static void bcache_exit(void) 2099 { 2100 bch_debug_exit(); 2101 bch_request_exit(); 2102 if (bcache_kobj) 2103 kobject_put(bcache_kobj); 2104 if (bcache_wq) 2105 destroy_workqueue(bcache_wq); 2106 if (bcache_major) 2107 unregister_blkdev(bcache_major, "bcache"); 2108 unregister_reboot_notifier(&reboot); 2109 mutex_destroy(&bch_register_lock); 2110 } 2111 2112 static int __init bcache_init(void) 2113 { 2114 static const struct attribute *files[] = { 2115 &ksysfs_register.attr, 2116 &ksysfs_register_quiet.attr, 2117 NULL 2118 }; 2119 2120 mutex_init(&bch_register_lock); 2121 init_waitqueue_head(&unregister_wait); 2122 register_reboot_notifier(&reboot); 2123 closure_debug_init(); 2124 2125 bcache_major = register_blkdev(0, "bcache"); 2126 if (bcache_major < 0) { 2127 unregister_reboot_notifier(&reboot); 2128 mutex_destroy(&bch_register_lock); 2129 return bcache_major; 2130 } 2131 2132 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) || 2133 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || 2134 bch_request_init() || 2135 bch_debug_init(bcache_kobj) || 2136 sysfs_create_files(bcache_kobj, files)) 2137 goto err; 2138 2139 return 0; 2140 err: 2141 bcache_exit(); 2142 return -ENOMEM; 2143 } 2144 2145 module_exit(bcache_exit); 2146 module_init(bcache_init); 2147