1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * bcache setup/teardown code, and some metadata io - read a superblock and 4 * figure out what to do with it. 5 * 6 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> 7 * Copyright 2012 Google, Inc. 8 */ 9 10 #include "bcache.h" 11 #include "btree.h" 12 #include "debug.h" 13 #include "extents.h" 14 #include "request.h" 15 #include "writeback.h" 16 17 #include <linux/blkdev.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 unsigned int bch_cutoff_writeback; 28 unsigned int bch_cutoff_writeback_sync; 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 static struct kobject *bcache_kobj; 41 struct mutex bch_register_lock; 42 bool bcache_is_reboot; 43 LIST_HEAD(bch_cache_sets); 44 static LIST_HEAD(uncached_devices); 45 46 static int bcache_major; 47 static DEFINE_IDA(bcache_device_idx); 48 static wait_queue_head_t unregister_wait; 49 struct workqueue_struct *bcache_wq; 50 struct workqueue_struct *bch_journal_wq; 51 52 53 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 54 /* limitation of partitions number on single bcache device */ 55 #define BCACHE_MINORS 128 56 /* limitation of bcache devices number on single system */ 57 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 58 59 /* Superblock */ 60 61 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 62 struct cache_sb_disk **res) 63 { 64 const char *err; 65 struct cache_sb_disk *s; 66 struct page *page; 67 unsigned int i; 68 69 page = read_cache_page_gfp(bdev->bd_inode->i_mapping, 70 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL); 71 if (IS_ERR(page)) 72 return "IO error"; 73 s = page_address(page) + offset_in_page(SB_OFFSET); 74 75 sb->offset = le64_to_cpu(s->offset); 76 sb->version = le64_to_cpu(s->version); 77 78 memcpy(sb->magic, s->magic, 16); 79 memcpy(sb->uuid, s->uuid, 16); 80 memcpy(sb->set_uuid, s->set_uuid, 16); 81 memcpy(sb->label, s->label, SB_LABEL_SIZE); 82 83 sb->flags = le64_to_cpu(s->flags); 84 sb->seq = le64_to_cpu(s->seq); 85 sb->last_mount = le32_to_cpu(s->last_mount); 86 sb->first_bucket = le16_to_cpu(s->first_bucket); 87 sb->keys = le16_to_cpu(s->keys); 88 89 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 90 sb->d[i] = le64_to_cpu(s->d[i]); 91 92 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 93 sb->version, sb->flags, sb->seq, sb->keys); 94 95 err = "Not a bcache superblock (bad offset)"; 96 if (sb->offset != SB_SECTOR) 97 goto err; 98 99 err = "Not a bcache superblock (bad magic)"; 100 if (memcmp(sb->magic, bcache_magic, 16)) 101 goto err; 102 103 err = "Too many journal buckets"; 104 if (sb->keys > SB_JOURNAL_BUCKETS) 105 goto err; 106 107 err = "Bad checksum"; 108 if (s->csum != csum_set(s)) 109 goto err; 110 111 err = "Bad UUID"; 112 if (bch_is_zero(sb->uuid, 16)) 113 goto err; 114 115 sb->block_size = le16_to_cpu(s->block_size); 116 117 err = "Superblock block size smaller than device block size"; 118 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 119 goto err; 120 121 switch (sb->version) { 122 case BCACHE_SB_VERSION_BDEV: 123 sb->data_offset = BDEV_DATA_START_DEFAULT; 124 break; 125 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 126 sb->data_offset = le64_to_cpu(s->data_offset); 127 128 err = "Bad data offset"; 129 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 130 goto err; 131 132 break; 133 case BCACHE_SB_VERSION_CDEV: 134 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 135 sb->nbuckets = le64_to_cpu(s->nbuckets); 136 sb->bucket_size = le16_to_cpu(s->bucket_size); 137 138 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 139 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 140 141 err = "Too many buckets"; 142 if (sb->nbuckets > LONG_MAX) 143 goto err; 144 145 err = "Not enough buckets"; 146 if (sb->nbuckets < 1 << 7) 147 goto err; 148 149 err = "Bad block/bucket size"; 150 if (!is_power_of_2(sb->block_size) || 151 sb->block_size > PAGE_SECTORS || 152 !is_power_of_2(sb->bucket_size) || 153 sb->bucket_size < PAGE_SECTORS) 154 goto err; 155 156 err = "Invalid superblock: device too small"; 157 if (get_capacity(bdev->bd_disk) < 158 sb->bucket_size * sb->nbuckets) 159 goto err; 160 161 err = "Bad UUID"; 162 if (bch_is_zero(sb->set_uuid, 16)) 163 goto err; 164 165 err = "Bad cache device number in set"; 166 if (!sb->nr_in_set || 167 sb->nr_in_set <= sb->nr_this_dev || 168 sb->nr_in_set > MAX_CACHES_PER_SET) 169 goto err; 170 171 err = "Journal buckets not sequential"; 172 for (i = 0; i < sb->keys; i++) 173 if (sb->d[i] != sb->first_bucket + i) 174 goto err; 175 176 err = "Too many journal buckets"; 177 if (sb->first_bucket + sb->keys > sb->nbuckets) 178 goto err; 179 180 err = "Invalid superblock: first bucket comes before end of super"; 181 if (sb->first_bucket * sb->bucket_size < 16) 182 goto err; 183 184 break; 185 default: 186 err = "Unsupported superblock version"; 187 goto err; 188 } 189 190 sb->last_mount = (u32)ktime_get_real_seconds(); 191 *res = s; 192 return NULL; 193 err: 194 put_page(page); 195 return err; 196 } 197 198 static void write_bdev_super_endio(struct bio *bio) 199 { 200 struct cached_dev *dc = bio->bi_private; 201 202 if (bio->bi_status) 203 bch_count_backing_io_errors(dc, bio); 204 205 closure_put(&dc->sb_write); 206 } 207 208 static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out, 209 struct bio *bio) 210 { 211 unsigned int i; 212 213 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META; 214 bio->bi_iter.bi_sector = SB_SECTOR; 215 __bio_add_page(bio, virt_to_page(out), SB_SIZE, 216 offset_in_page(out)); 217 218 out->offset = cpu_to_le64(sb->offset); 219 out->version = cpu_to_le64(sb->version); 220 221 memcpy(out->uuid, sb->uuid, 16); 222 memcpy(out->set_uuid, sb->set_uuid, 16); 223 memcpy(out->label, sb->label, SB_LABEL_SIZE); 224 225 out->flags = cpu_to_le64(sb->flags); 226 out->seq = cpu_to_le64(sb->seq); 227 228 out->last_mount = cpu_to_le32(sb->last_mount); 229 out->first_bucket = cpu_to_le16(sb->first_bucket); 230 out->keys = cpu_to_le16(sb->keys); 231 232 for (i = 0; i < sb->keys; i++) 233 out->d[i] = cpu_to_le64(sb->d[i]); 234 235 out->csum = csum_set(out); 236 237 pr_debug("ver %llu, flags %llu, seq %llu", 238 sb->version, sb->flags, sb->seq); 239 240 submit_bio(bio); 241 } 242 243 static void bch_write_bdev_super_unlock(struct closure *cl) 244 { 245 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 246 247 up(&dc->sb_write_mutex); 248 } 249 250 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 251 { 252 struct closure *cl = &dc->sb_write; 253 struct bio *bio = &dc->sb_bio; 254 255 down(&dc->sb_write_mutex); 256 closure_init(cl, parent); 257 258 bio_init(bio, dc->sb_bv, 1); 259 bio_set_dev(bio, dc->bdev); 260 bio->bi_end_io = write_bdev_super_endio; 261 bio->bi_private = dc; 262 263 closure_get(cl); 264 /* I/O request sent to backing device */ 265 __write_super(&dc->sb, dc->sb_disk, bio); 266 267 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 268 } 269 270 static void write_super_endio(struct bio *bio) 271 { 272 struct cache *ca = bio->bi_private; 273 274 /* is_read = 0 */ 275 bch_count_io_errors(ca, bio->bi_status, 0, 276 "writing superblock"); 277 closure_put(&ca->set->sb_write); 278 } 279 280 static void bcache_write_super_unlock(struct closure *cl) 281 { 282 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 283 284 up(&c->sb_write_mutex); 285 } 286 287 void bcache_write_super(struct cache_set *c) 288 { 289 struct closure *cl = &c->sb_write; 290 struct cache *ca; 291 unsigned int i; 292 293 down(&c->sb_write_mutex); 294 closure_init(cl, &c->cl); 295 296 c->sb.seq++; 297 298 for_each_cache(ca, c, i) { 299 struct bio *bio = &ca->sb_bio; 300 301 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 302 ca->sb.seq = c->sb.seq; 303 ca->sb.last_mount = c->sb.last_mount; 304 305 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 306 307 bio_init(bio, ca->sb_bv, 1); 308 bio_set_dev(bio, ca->bdev); 309 bio->bi_end_io = write_super_endio; 310 bio->bi_private = ca; 311 312 closure_get(cl); 313 __write_super(&ca->sb, ca->sb_disk, bio); 314 } 315 316 closure_return_with_destructor(cl, bcache_write_super_unlock); 317 } 318 319 /* UUID io */ 320 321 static void uuid_endio(struct bio *bio) 322 { 323 struct closure *cl = bio->bi_private; 324 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 325 326 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 327 bch_bbio_free(bio, c); 328 closure_put(cl); 329 } 330 331 static void uuid_io_unlock(struct closure *cl) 332 { 333 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 334 335 up(&c->uuid_write_mutex); 336 } 337 338 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 339 struct bkey *k, struct closure *parent) 340 { 341 struct closure *cl = &c->uuid_write; 342 struct uuid_entry *u; 343 unsigned int i; 344 char buf[80]; 345 346 BUG_ON(!parent); 347 down(&c->uuid_write_mutex); 348 closure_init(cl, parent); 349 350 for (i = 0; i < KEY_PTRS(k); i++) { 351 struct bio *bio = bch_bbio_alloc(c); 352 353 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 354 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 355 356 bio->bi_end_io = uuid_endio; 357 bio->bi_private = cl; 358 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 359 bch_bio_map(bio, c->uuids); 360 361 bch_submit_bbio(bio, c, k, i); 362 363 if (op != REQ_OP_WRITE) 364 break; 365 } 366 367 bch_extent_to_text(buf, sizeof(buf), k); 368 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 369 370 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 371 if (!bch_is_zero(u->uuid, 16)) 372 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 373 u - c->uuids, u->uuid, u->label, 374 u->first_reg, u->last_reg, u->invalidated); 375 376 closure_return_with_destructor(cl, uuid_io_unlock); 377 } 378 379 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 380 { 381 struct bkey *k = &j->uuid_bucket; 382 383 if (__bch_btree_ptr_invalid(c, k)) 384 return "bad uuid pointer"; 385 386 bkey_copy(&c->uuid_bucket, k); 387 uuid_io(c, REQ_OP_READ, 0, k, cl); 388 389 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 390 struct uuid_entry_v0 *u0 = (void *) c->uuids; 391 struct uuid_entry *u1 = (void *) c->uuids; 392 int i; 393 394 closure_sync(cl); 395 396 /* 397 * Since the new uuid entry is bigger than the old, we have to 398 * convert starting at the highest memory address and work down 399 * in order to do it in place 400 */ 401 402 for (i = c->nr_uuids - 1; 403 i >= 0; 404 --i) { 405 memcpy(u1[i].uuid, u0[i].uuid, 16); 406 memcpy(u1[i].label, u0[i].label, 32); 407 408 u1[i].first_reg = u0[i].first_reg; 409 u1[i].last_reg = u0[i].last_reg; 410 u1[i].invalidated = u0[i].invalidated; 411 412 u1[i].flags = 0; 413 u1[i].sectors = 0; 414 } 415 } 416 417 return NULL; 418 } 419 420 static int __uuid_write(struct cache_set *c) 421 { 422 BKEY_PADDED(key) k; 423 struct closure cl; 424 struct cache *ca; 425 426 closure_init_stack(&cl); 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 /* Only one bucket used for uuid write */ 437 ca = PTR_CACHE(c, &k.key, 0); 438 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written); 439 440 bkey_copy(&c->uuid_bucket, &k.key); 441 bkey_put(c, &k.key); 442 return 0; 443 } 444 445 int bch_uuid_write(struct cache_set *c) 446 { 447 int ret = __uuid_write(c); 448 449 if (!ret) 450 bch_journal_meta(c, NULL); 451 452 return ret; 453 } 454 455 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 456 { 457 struct uuid_entry *u; 458 459 for (u = c->uuids; 460 u < c->uuids + c->nr_uuids; u++) 461 if (!memcmp(u->uuid, uuid, 16)) 462 return u; 463 464 return NULL; 465 } 466 467 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 468 { 469 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 470 471 return uuid_find(c, zero_uuid); 472 } 473 474 /* 475 * Bucket priorities/gens: 476 * 477 * For each bucket, we store on disk its 478 * 8 bit gen 479 * 16 bit priority 480 * 481 * See alloc.c for an explanation of the gen. The priority is used to implement 482 * lru (and in the future other) cache replacement policies; for most purposes 483 * it's just an opaque integer. 484 * 485 * The gens and the priorities don't have a whole lot to do with each other, and 486 * it's actually the gens that must be written out at specific times - it's no 487 * big deal if the priorities don't get written, if we lose them we just reuse 488 * buckets in suboptimal order. 489 * 490 * On disk they're stored in a packed array, and in as many buckets are required 491 * to fit them all. The buckets we use to store them form a list; the journal 492 * header points to the first bucket, the first bucket points to the second 493 * bucket, et cetera. 494 * 495 * This code is used by the allocation code; periodically (whenever it runs out 496 * of buckets to allocate from) the allocation code will invalidate some 497 * buckets, but it can't use those buckets until their new gens are safely on 498 * disk. 499 */ 500 501 static void prio_endio(struct bio *bio) 502 { 503 struct cache *ca = bio->bi_private; 504 505 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 506 bch_bbio_free(bio, ca->set); 507 closure_put(&ca->prio); 508 } 509 510 static void prio_io(struct cache *ca, uint64_t bucket, int op, 511 unsigned long op_flags) 512 { 513 struct closure *cl = &ca->prio; 514 struct bio *bio = bch_bbio_alloc(ca->set); 515 516 closure_init_stack(cl); 517 518 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 519 bio_set_dev(bio, ca->bdev); 520 bio->bi_iter.bi_size = bucket_bytes(ca); 521 522 bio->bi_end_io = prio_endio; 523 bio->bi_private = ca; 524 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 525 bch_bio_map(bio, ca->disk_buckets); 526 527 closure_bio_submit(ca->set, bio, &ca->prio); 528 closure_sync(cl); 529 } 530 531 int bch_prio_write(struct cache *ca, bool wait) 532 { 533 int i; 534 struct bucket *b; 535 struct closure cl; 536 537 pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu", 538 fifo_used(&ca->free[RESERVE_PRIO]), 539 fifo_used(&ca->free[RESERVE_NONE]), 540 fifo_used(&ca->free_inc)); 541 542 /* 543 * Pre-check if there are enough free buckets. In the non-blocking 544 * scenario it's better to fail early rather than starting to allocate 545 * buckets and do a cleanup later in case of failure. 546 */ 547 if (!wait) { 548 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) + 549 fifo_used(&ca->free[RESERVE_NONE]); 550 if (prio_buckets(ca) > avail) 551 return -ENOMEM; 552 } 553 554 closure_init_stack(&cl); 555 556 lockdep_assert_held(&ca->set->bucket_lock); 557 558 ca->disk_buckets->seq++; 559 560 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 561 &ca->meta_sectors_written); 562 563 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 564 long bucket; 565 struct prio_set *p = ca->disk_buckets; 566 struct bucket_disk *d = p->data; 567 struct bucket_disk *end = d + prios_per_bucket(ca); 568 569 for (b = ca->buckets + i * prios_per_bucket(ca); 570 b < ca->buckets + ca->sb.nbuckets && d < end; 571 b++, d++) { 572 d->prio = cpu_to_le16(b->prio); 573 d->gen = b->gen; 574 } 575 576 p->next_bucket = ca->prio_buckets[i + 1]; 577 p->magic = pset_magic(&ca->sb); 578 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 579 580 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait); 581 BUG_ON(bucket == -1); 582 583 mutex_unlock(&ca->set->bucket_lock); 584 prio_io(ca, bucket, REQ_OP_WRITE, 0); 585 mutex_lock(&ca->set->bucket_lock); 586 587 ca->prio_buckets[i] = bucket; 588 atomic_dec_bug(&ca->buckets[bucket].pin); 589 } 590 591 mutex_unlock(&ca->set->bucket_lock); 592 593 bch_journal_meta(ca->set, &cl); 594 closure_sync(&cl); 595 596 mutex_lock(&ca->set->bucket_lock); 597 598 /* 599 * Don't want the old priorities to get garbage collected until after we 600 * finish writing the new ones, and they're journalled 601 */ 602 for (i = 0; i < prio_buckets(ca); i++) { 603 if (ca->prio_last_buckets[i]) 604 __bch_bucket_free(ca, 605 &ca->buckets[ca->prio_last_buckets[i]]); 606 607 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 608 } 609 return 0; 610 } 611 612 static int prio_read(struct cache *ca, uint64_t bucket) 613 { 614 struct prio_set *p = ca->disk_buckets; 615 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 616 struct bucket *b; 617 unsigned int bucket_nr = 0; 618 int ret = -EIO; 619 620 for (b = ca->buckets; 621 b < ca->buckets + ca->sb.nbuckets; 622 b++, d++) { 623 if (d == end) { 624 ca->prio_buckets[bucket_nr] = bucket; 625 ca->prio_last_buckets[bucket_nr] = bucket; 626 bucket_nr++; 627 628 prio_io(ca, bucket, REQ_OP_READ, 0); 629 630 if (p->csum != 631 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) { 632 pr_warn("bad csum reading priorities"); 633 goto out; 634 } 635 636 if (p->magic != pset_magic(&ca->sb)) { 637 pr_warn("bad magic reading priorities"); 638 goto out; 639 } 640 641 bucket = p->next_bucket; 642 d = p->data; 643 } 644 645 b->prio = le16_to_cpu(d->prio); 646 b->gen = b->last_gc = d->gen; 647 } 648 649 ret = 0; 650 out: 651 return ret; 652 } 653 654 /* Bcache device */ 655 656 static int open_dev(struct block_device *b, fmode_t mode) 657 { 658 struct bcache_device *d = b->bd_disk->private_data; 659 660 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 661 return -ENXIO; 662 663 closure_get(&d->cl); 664 return 0; 665 } 666 667 static void release_dev(struct gendisk *b, fmode_t mode) 668 { 669 struct bcache_device *d = b->private_data; 670 671 closure_put(&d->cl); 672 } 673 674 static int ioctl_dev(struct block_device *b, fmode_t mode, 675 unsigned int cmd, unsigned long arg) 676 { 677 struct bcache_device *d = b->bd_disk->private_data; 678 679 return d->ioctl(d, mode, cmd, arg); 680 } 681 682 static const struct block_device_operations bcache_ops = { 683 .open = open_dev, 684 .release = release_dev, 685 .ioctl = ioctl_dev, 686 .owner = THIS_MODULE, 687 }; 688 689 void bcache_device_stop(struct bcache_device *d) 690 { 691 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 692 /* 693 * closure_fn set to 694 * - cached device: cached_dev_flush() 695 * - flash dev: flash_dev_flush() 696 */ 697 closure_queue(&d->cl); 698 } 699 700 static void bcache_device_unlink(struct bcache_device *d) 701 { 702 lockdep_assert_held(&bch_register_lock); 703 704 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 705 unsigned int i; 706 struct cache *ca; 707 708 sysfs_remove_link(&d->c->kobj, d->name); 709 sysfs_remove_link(&d->kobj, "cache"); 710 711 for_each_cache(ca, d->c, i) 712 bd_unlink_disk_holder(ca->bdev, d->disk); 713 } 714 } 715 716 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 717 const char *name) 718 { 719 unsigned int i; 720 struct cache *ca; 721 int ret; 722 723 for_each_cache(ca, d->c, i) 724 bd_link_disk_holder(ca->bdev, d->disk); 725 726 snprintf(d->name, BCACHEDEVNAME_SIZE, 727 "%s%u", name, d->id); 728 729 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache"); 730 if (ret < 0) 731 pr_err("Couldn't create device -> cache set symlink"); 732 733 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name); 734 if (ret < 0) 735 pr_err("Couldn't create cache set -> device symlink"); 736 737 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 738 } 739 740 static void bcache_device_detach(struct bcache_device *d) 741 { 742 lockdep_assert_held(&bch_register_lock); 743 744 atomic_dec(&d->c->attached_dev_nr); 745 746 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 747 struct uuid_entry *u = d->c->uuids + d->id; 748 749 SET_UUID_FLASH_ONLY(u, 0); 750 memcpy(u->uuid, invalid_uuid, 16); 751 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 752 bch_uuid_write(d->c); 753 } 754 755 bcache_device_unlink(d); 756 757 d->c->devices[d->id] = NULL; 758 closure_put(&d->c->caching); 759 d->c = NULL; 760 } 761 762 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 763 unsigned int id) 764 { 765 d->id = id; 766 d->c = c; 767 c->devices[id] = d; 768 769 if (id >= c->devices_max_used) 770 c->devices_max_used = id + 1; 771 772 closure_get(&c->caching); 773 } 774 775 static inline int first_minor_to_idx(int first_minor) 776 { 777 return (first_minor/BCACHE_MINORS); 778 } 779 780 static inline int idx_to_first_minor(int idx) 781 { 782 return (idx * BCACHE_MINORS); 783 } 784 785 static void bcache_device_free(struct bcache_device *d) 786 { 787 struct gendisk *disk = d->disk; 788 789 lockdep_assert_held(&bch_register_lock); 790 791 if (disk) 792 pr_info("%s stopped", disk->disk_name); 793 else 794 pr_err("bcache device (NULL gendisk) stopped"); 795 796 if (d->c) 797 bcache_device_detach(d); 798 799 if (disk) { 800 if (disk->flags & GENHD_FL_UP) 801 del_gendisk(disk); 802 803 if (disk->queue) 804 blk_cleanup_queue(disk->queue); 805 806 ida_simple_remove(&bcache_device_idx, 807 first_minor_to_idx(disk->first_minor)); 808 put_disk(disk); 809 } 810 811 bioset_exit(&d->bio_split); 812 kvfree(d->full_dirty_stripes); 813 kvfree(d->stripe_sectors_dirty); 814 815 closure_debug_destroy(&d->cl); 816 } 817 818 static int bcache_device_init(struct bcache_device *d, unsigned int block_size, 819 sector_t sectors, make_request_fn make_request_fn) 820 { 821 struct request_queue *q; 822 const size_t max_stripes = min_t(size_t, INT_MAX, 823 SIZE_MAX / sizeof(atomic_t)); 824 size_t n; 825 int idx; 826 827 if (!d->stripe_size) 828 d->stripe_size = 1 << 31; 829 830 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 831 832 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 833 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 834 (unsigned int)d->nr_stripes); 835 return -ENOMEM; 836 } 837 838 n = d->nr_stripes * sizeof(atomic_t); 839 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 840 if (!d->stripe_sectors_dirty) 841 return -ENOMEM; 842 843 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 844 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 845 if (!d->full_dirty_stripes) 846 return -ENOMEM; 847 848 idx = ida_simple_get(&bcache_device_idx, 0, 849 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 850 if (idx < 0) 851 return idx; 852 853 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 854 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) 855 goto err; 856 857 d->disk = alloc_disk(BCACHE_MINORS); 858 if (!d->disk) 859 goto err; 860 861 set_capacity(d->disk, sectors); 862 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 863 864 d->disk->major = bcache_major; 865 d->disk->first_minor = idx_to_first_minor(idx); 866 d->disk->fops = &bcache_ops; 867 d->disk->private_data = d; 868 869 q = blk_alloc_queue(make_request_fn, NUMA_NO_NODE); 870 if (!q) 871 return -ENOMEM; 872 873 d->disk->queue = q; 874 q->queuedata = d; 875 q->backing_dev_info->congested_data = d; 876 q->limits.max_hw_sectors = UINT_MAX; 877 q->limits.max_sectors = UINT_MAX; 878 q->limits.max_segment_size = UINT_MAX; 879 q->limits.max_segments = BIO_MAX_PAGES; 880 blk_queue_max_discard_sectors(q, UINT_MAX); 881 q->limits.discard_granularity = 512; 882 q->limits.io_min = block_size; 883 q->limits.logical_block_size = block_size; 884 q->limits.physical_block_size = block_size; 885 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 886 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 887 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 888 889 blk_queue_write_cache(q, true, true); 890 891 return 0; 892 893 err: 894 ida_simple_remove(&bcache_device_idx, idx); 895 return -ENOMEM; 896 897 } 898 899 /* Cached device */ 900 901 static void calc_cached_dev_sectors(struct cache_set *c) 902 { 903 uint64_t sectors = 0; 904 struct cached_dev *dc; 905 906 list_for_each_entry(dc, &c->cached_devs, list) 907 sectors += bdev_sectors(dc->bdev); 908 909 c->cached_dev_sectors = sectors; 910 } 911 912 #define BACKING_DEV_OFFLINE_TIMEOUT 5 913 static int cached_dev_status_update(void *arg) 914 { 915 struct cached_dev *dc = arg; 916 struct request_queue *q; 917 918 /* 919 * If this delayed worker is stopping outside, directly quit here. 920 * dc->io_disable might be set via sysfs interface, so check it 921 * here too. 922 */ 923 while (!kthread_should_stop() && !dc->io_disable) { 924 q = bdev_get_queue(dc->bdev); 925 if (blk_queue_dying(q)) 926 dc->offline_seconds++; 927 else 928 dc->offline_seconds = 0; 929 930 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 931 pr_err("%s: device offline for %d seconds", 932 dc->backing_dev_name, 933 BACKING_DEV_OFFLINE_TIMEOUT); 934 pr_err("%s: disable I/O request due to backing " 935 "device offline", dc->disk.name); 936 dc->io_disable = true; 937 /* let others know earlier that io_disable is true */ 938 smp_mb(); 939 bcache_device_stop(&dc->disk); 940 break; 941 } 942 schedule_timeout_interruptible(HZ); 943 } 944 945 wait_for_kthread_stop(); 946 return 0; 947 } 948 949 950 int bch_cached_dev_run(struct cached_dev *dc) 951 { 952 struct bcache_device *d = &dc->disk; 953 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL); 954 char *env[] = { 955 "DRIVER=bcache", 956 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 957 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""), 958 NULL, 959 }; 960 961 if (dc->io_disable) { 962 pr_err("I/O disabled on cached dev %s", 963 dc->backing_dev_name); 964 kfree(env[1]); 965 kfree(env[2]); 966 kfree(buf); 967 return -EIO; 968 } 969 970 if (atomic_xchg(&dc->running, 1)) { 971 kfree(env[1]); 972 kfree(env[2]); 973 kfree(buf); 974 pr_info("cached dev %s is running already", 975 dc->backing_dev_name); 976 return -EBUSY; 977 } 978 979 if (!d->c && 980 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 981 struct closure cl; 982 983 closure_init_stack(&cl); 984 985 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 986 bch_write_bdev_super(dc, &cl); 987 closure_sync(&cl); 988 } 989 990 add_disk(d->disk); 991 bd_link_disk_holder(dc->bdev, dc->disk.disk); 992 /* 993 * won't show up in the uevent file, use udevadm monitor -e instead 994 * only class / kset properties are persistent 995 */ 996 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 997 kfree(env[1]); 998 kfree(env[2]); 999 kfree(buf); 1000 1001 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 1002 sysfs_create_link(&disk_to_dev(d->disk)->kobj, 1003 &d->kobj, "bcache")) { 1004 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks"); 1005 return -ENOMEM; 1006 } 1007 1008 dc->status_update_thread = kthread_run(cached_dev_status_update, 1009 dc, "bcache_status_update"); 1010 if (IS_ERR(dc->status_update_thread)) { 1011 pr_warn("failed to create bcache_status_update kthread, " 1012 "continue to run without monitoring backing " 1013 "device status"); 1014 } 1015 1016 return 0; 1017 } 1018 1019 /* 1020 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 1021 * work dc->writeback_rate_update is running. Wait until the routine 1022 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 1023 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 1024 * seconds, give up waiting here and continue to cancel it too. 1025 */ 1026 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 1027 { 1028 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 1029 1030 do { 1031 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 1032 &dc->disk.flags)) 1033 break; 1034 time_out--; 1035 schedule_timeout_interruptible(1); 1036 } while (time_out > 0); 1037 1038 if (time_out == 0) 1039 pr_warn("give up waiting for dc->writeback_write_update to quit"); 1040 1041 cancel_delayed_work_sync(&dc->writeback_rate_update); 1042 } 1043 1044 static void cached_dev_detach_finish(struct work_struct *w) 1045 { 1046 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 1047 struct closure cl; 1048 1049 closure_init_stack(&cl); 1050 1051 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 1052 BUG_ON(refcount_read(&dc->count)); 1053 1054 1055 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1056 cancel_writeback_rate_update_dwork(dc); 1057 1058 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 1059 kthread_stop(dc->writeback_thread); 1060 dc->writeback_thread = NULL; 1061 } 1062 1063 memset(&dc->sb.set_uuid, 0, 16); 1064 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 1065 1066 bch_write_bdev_super(dc, &cl); 1067 closure_sync(&cl); 1068 1069 mutex_lock(&bch_register_lock); 1070 1071 calc_cached_dev_sectors(dc->disk.c); 1072 bcache_device_detach(&dc->disk); 1073 list_move(&dc->list, &uncached_devices); 1074 1075 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1076 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1077 1078 mutex_unlock(&bch_register_lock); 1079 1080 pr_info("Caching disabled for %s", dc->backing_dev_name); 1081 1082 /* Drop ref we took in cached_dev_detach() */ 1083 closure_put(&dc->disk.cl); 1084 } 1085 1086 void bch_cached_dev_detach(struct cached_dev *dc) 1087 { 1088 lockdep_assert_held(&bch_register_lock); 1089 1090 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1091 return; 1092 1093 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1094 return; 1095 1096 /* 1097 * Block the device from being closed and freed until we're finished 1098 * detaching 1099 */ 1100 closure_get(&dc->disk.cl); 1101 1102 bch_writeback_queue(dc); 1103 1104 cached_dev_put(dc); 1105 } 1106 1107 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1108 uint8_t *set_uuid) 1109 { 1110 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); 1111 struct uuid_entry *u; 1112 struct cached_dev *exist_dc, *t; 1113 int ret = 0; 1114 1115 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1116 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1117 return -ENOENT; 1118 1119 if (dc->disk.c) { 1120 pr_err("Can't attach %s: already attached", 1121 dc->backing_dev_name); 1122 return -EINVAL; 1123 } 1124 1125 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1126 pr_err("Can't attach %s: shutting down", 1127 dc->backing_dev_name); 1128 return -EINVAL; 1129 } 1130 1131 if (dc->sb.block_size < c->sb.block_size) { 1132 /* Will die */ 1133 pr_err("Couldn't attach %s: block size less than set's block size", 1134 dc->backing_dev_name); 1135 return -EINVAL; 1136 } 1137 1138 /* Check whether already attached */ 1139 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1140 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1141 pr_err("Tried to attach %s but duplicate UUID already attached", 1142 dc->backing_dev_name); 1143 1144 return -EINVAL; 1145 } 1146 } 1147 1148 u = uuid_find(c, dc->sb.uuid); 1149 1150 if (u && 1151 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1152 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1153 memcpy(u->uuid, invalid_uuid, 16); 1154 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 1155 u = NULL; 1156 } 1157 1158 if (!u) { 1159 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1160 pr_err("Couldn't find uuid for %s in set", 1161 dc->backing_dev_name); 1162 return -ENOENT; 1163 } 1164 1165 u = uuid_find_empty(c); 1166 if (!u) { 1167 pr_err("Not caching %s, no room for UUID", 1168 dc->backing_dev_name); 1169 return -EINVAL; 1170 } 1171 } 1172 1173 /* 1174 * Deadlocks since we're called via sysfs... 1175 * sysfs_remove_file(&dc->kobj, &sysfs_attach); 1176 */ 1177 1178 if (bch_is_zero(u->uuid, 16)) { 1179 struct closure cl; 1180 1181 closure_init_stack(&cl); 1182 1183 memcpy(u->uuid, dc->sb.uuid, 16); 1184 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1185 u->first_reg = u->last_reg = rtime; 1186 bch_uuid_write(c); 1187 1188 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1189 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1190 1191 bch_write_bdev_super(dc, &cl); 1192 closure_sync(&cl); 1193 } else { 1194 u->last_reg = rtime; 1195 bch_uuid_write(c); 1196 } 1197 1198 bcache_device_attach(&dc->disk, c, u - c->uuids); 1199 list_move(&dc->list, &c->cached_devs); 1200 calc_cached_dev_sectors(c); 1201 1202 /* 1203 * dc->c must be set before dc->count != 0 - paired with the mb in 1204 * cached_dev_get() 1205 */ 1206 smp_wmb(); 1207 refcount_set(&dc->count, 1); 1208 1209 /* Block writeback thread, but spawn it */ 1210 down_write(&dc->writeback_lock); 1211 if (bch_cached_dev_writeback_start(dc)) { 1212 up_write(&dc->writeback_lock); 1213 pr_err("Couldn't start writeback facilities for %s", 1214 dc->disk.disk->disk_name); 1215 return -ENOMEM; 1216 } 1217 1218 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1219 atomic_set(&dc->has_dirty, 1); 1220 bch_writeback_queue(dc); 1221 } 1222 1223 bch_sectors_dirty_init(&dc->disk); 1224 1225 ret = bch_cached_dev_run(dc); 1226 if (ret && (ret != -EBUSY)) { 1227 up_write(&dc->writeback_lock); 1228 /* 1229 * bch_register_lock is held, bcache_device_stop() is not 1230 * able to be directly called. The kthread and kworker 1231 * created previously in bch_cached_dev_writeback_start() 1232 * have to be stopped manually here. 1233 */ 1234 kthread_stop(dc->writeback_thread); 1235 cancel_writeback_rate_update_dwork(dc); 1236 pr_err("Couldn't run cached device %s", 1237 dc->backing_dev_name); 1238 return ret; 1239 } 1240 1241 bcache_device_link(&dc->disk, c, "bdev"); 1242 atomic_inc(&c->attached_dev_nr); 1243 1244 /* Allow the writeback thread to proceed */ 1245 up_write(&dc->writeback_lock); 1246 1247 pr_info("Caching %s as %s on set %pU", 1248 dc->backing_dev_name, 1249 dc->disk.disk->disk_name, 1250 dc->disk.c->sb.set_uuid); 1251 return 0; 1252 } 1253 1254 /* when dc->disk.kobj released */ 1255 void bch_cached_dev_release(struct kobject *kobj) 1256 { 1257 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1258 disk.kobj); 1259 kfree(dc); 1260 module_put(THIS_MODULE); 1261 } 1262 1263 static void cached_dev_free(struct closure *cl) 1264 { 1265 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1266 1267 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1268 cancel_writeback_rate_update_dwork(dc); 1269 1270 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1271 kthread_stop(dc->writeback_thread); 1272 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1273 kthread_stop(dc->status_update_thread); 1274 1275 mutex_lock(&bch_register_lock); 1276 1277 if (atomic_read(&dc->running)) 1278 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1279 bcache_device_free(&dc->disk); 1280 list_del(&dc->list); 1281 1282 mutex_unlock(&bch_register_lock); 1283 1284 if (dc->sb_disk) 1285 put_page(virt_to_page(dc->sb_disk)); 1286 1287 if (!IS_ERR_OR_NULL(dc->bdev)) 1288 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1289 1290 wake_up(&unregister_wait); 1291 1292 kobject_put(&dc->disk.kobj); 1293 } 1294 1295 static void cached_dev_flush(struct closure *cl) 1296 { 1297 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1298 struct bcache_device *d = &dc->disk; 1299 1300 mutex_lock(&bch_register_lock); 1301 bcache_device_unlink(d); 1302 mutex_unlock(&bch_register_lock); 1303 1304 bch_cache_accounting_destroy(&dc->accounting); 1305 kobject_del(&d->kobj); 1306 1307 continue_at(cl, cached_dev_free, system_wq); 1308 } 1309 1310 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size) 1311 { 1312 int ret; 1313 struct io *io; 1314 struct request_queue *q = bdev_get_queue(dc->bdev); 1315 1316 __module_get(THIS_MODULE); 1317 INIT_LIST_HEAD(&dc->list); 1318 closure_init(&dc->disk.cl, NULL); 1319 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1320 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1321 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1322 sema_init(&dc->sb_write_mutex, 1); 1323 INIT_LIST_HEAD(&dc->io_lru); 1324 spin_lock_init(&dc->io_lock); 1325 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1326 1327 dc->sequential_cutoff = 4 << 20; 1328 1329 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1330 list_add(&io->lru, &dc->io_lru); 1331 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1332 } 1333 1334 dc->disk.stripe_size = q->limits.io_opt >> 9; 1335 1336 if (dc->disk.stripe_size) 1337 dc->partial_stripes_expensive = 1338 q->limits.raid_partial_stripes_expensive; 1339 1340 ret = bcache_device_init(&dc->disk, block_size, 1341 dc->bdev->bd_part->nr_sects - dc->sb.data_offset, 1342 cached_dev_make_request); 1343 if (ret) 1344 return ret; 1345 1346 dc->disk.disk->queue->backing_dev_info->ra_pages = 1347 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1348 q->backing_dev_info->ra_pages); 1349 1350 atomic_set(&dc->io_errors, 0); 1351 dc->io_disable = false; 1352 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1353 /* default to auto */ 1354 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1355 1356 bch_cached_dev_request_init(dc); 1357 bch_cached_dev_writeback_init(dc); 1358 return 0; 1359 } 1360 1361 /* Cached device - bcache superblock */ 1362 1363 static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk, 1364 struct block_device *bdev, 1365 struct cached_dev *dc) 1366 { 1367 const char *err = "cannot allocate memory"; 1368 struct cache_set *c; 1369 int ret = -ENOMEM; 1370 1371 bdevname(bdev, dc->backing_dev_name); 1372 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1373 dc->bdev = bdev; 1374 dc->bdev->bd_holder = dc; 1375 dc->sb_disk = sb_disk; 1376 1377 if (cached_dev_init(dc, sb->block_size << 9)) 1378 goto err; 1379 1380 err = "error creating kobject"; 1381 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1382 "bcache")) 1383 goto err; 1384 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1385 goto err; 1386 1387 pr_info("registered backing device %s", dc->backing_dev_name); 1388 1389 list_add(&dc->list, &uncached_devices); 1390 /* attach to a matched cache set if it exists */ 1391 list_for_each_entry(c, &bch_cache_sets, list) 1392 bch_cached_dev_attach(dc, c, NULL); 1393 1394 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1395 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) { 1396 err = "failed to run cached device"; 1397 ret = bch_cached_dev_run(dc); 1398 if (ret) 1399 goto err; 1400 } 1401 1402 return 0; 1403 err: 1404 pr_notice("error %s: %s", dc->backing_dev_name, err); 1405 bcache_device_stop(&dc->disk); 1406 return ret; 1407 } 1408 1409 /* Flash only volumes */ 1410 1411 /* When d->kobj released */ 1412 void bch_flash_dev_release(struct kobject *kobj) 1413 { 1414 struct bcache_device *d = container_of(kobj, struct bcache_device, 1415 kobj); 1416 kfree(d); 1417 } 1418 1419 static void flash_dev_free(struct closure *cl) 1420 { 1421 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1422 1423 mutex_lock(&bch_register_lock); 1424 atomic_long_sub(bcache_dev_sectors_dirty(d), 1425 &d->c->flash_dev_dirty_sectors); 1426 bcache_device_free(d); 1427 mutex_unlock(&bch_register_lock); 1428 kobject_put(&d->kobj); 1429 } 1430 1431 static void flash_dev_flush(struct closure *cl) 1432 { 1433 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1434 1435 mutex_lock(&bch_register_lock); 1436 bcache_device_unlink(d); 1437 mutex_unlock(&bch_register_lock); 1438 kobject_del(&d->kobj); 1439 continue_at(cl, flash_dev_free, system_wq); 1440 } 1441 1442 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1443 { 1444 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1445 GFP_KERNEL); 1446 if (!d) 1447 return -ENOMEM; 1448 1449 closure_init(&d->cl, NULL); 1450 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1451 1452 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1453 1454 if (bcache_device_init(d, block_bytes(c), u->sectors, 1455 flash_dev_make_request)) 1456 goto err; 1457 1458 bcache_device_attach(d, c, u - c->uuids); 1459 bch_sectors_dirty_init(d); 1460 bch_flash_dev_request_init(d); 1461 add_disk(d->disk); 1462 1463 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1464 goto err; 1465 1466 bcache_device_link(d, c, "volume"); 1467 1468 return 0; 1469 err: 1470 kobject_put(&d->kobj); 1471 return -ENOMEM; 1472 } 1473 1474 static int flash_devs_run(struct cache_set *c) 1475 { 1476 int ret = 0; 1477 struct uuid_entry *u; 1478 1479 for (u = c->uuids; 1480 u < c->uuids + c->nr_uuids && !ret; 1481 u++) 1482 if (UUID_FLASH_ONLY(u)) 1483 ret = flash_dev_run(c, u); 1484 1485 return ret; 1486 } 1487 1488 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1489 { 1490 struct uuid_entry *u; 1491 1492 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1493 return -EINTR; 1494 1495 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1496 return -EPERM; 1497 1498 u = uuid_find_empty(c); 1499 if (!u) { 1500 pr_err("Can't create volume, no room for UUID"); 1501 return -EINVAL; 1502 } 1503 1504 get_random_bytes(u->uuid, 16); 1505 memset(u->label, 0, 32); 1506 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); 1507 1508 SET_UUID_FLASH_ONLY(u, 1); 1509 u->sectors = size >> 9; 1510 1511 bch_uuid_write(c); 1512 1513 return flash_dev_run(c, u); 1514 } 1515 1516 bool bch_cached_dev_error(struct cached_dev *dc) 1517 { 1518 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1519 return false; 1520 1521 dc->io_disable = true; 1522 /* make others know io_disable is true earlier */ 1523 smp_mb(); 1524 1525 pr_err("stop %s: too many IO errors on backing device %s\n", 1526 dc->disk.disk->disk_name, dc->backing_dev_name); 1527 1528 bcache_device_stop(&dc->disk); 1529 return true; 1530 } 1531 1532 /* Cache set */ 1533 1534 __printf(2, 3) 1535 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1536 { 1537 va_list args; 1538 1539 if (c->on_error != ON_ERROR_PANIC && 1540 test_bit(CACHE_SET_STOPPING, &c->flags)) 1541 return false; 1542 1543 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1544 pr_info("CACHE_SET_IO_DISABLE already set"); 1545 1546 /* 1547 * XXX: we can be called from atomic context 1548 * acquire_console_sem(); 1549 */ 1550 1551 pr_err("bcache: error on %pU: ", c->sb.set_uuid); 1552 1553 va_start(args, fmt); 1554 vprintk(fmt, args); 1555 va_end(args); 1556 1557 pr_err(", disabling caching\n"); 1558 1559 if (c->on_error == ON_ERROR_PANIC) 1560 panic("panic forced after error\n"); 1561 1562 bch_cache_set_unregister(c); 1563 return true; 1564 } 1565 1566 /* When c->kobj released */ 1567 void bch_cache_set_release(struct kobject *kobj) 1568 { 1569 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1570 1571 kfree(c); 1572 module_put(THIS_MODULE); 1573 } 1574 1575 static void cache_set_free(struct closure *cl) 1576 { 1577 struct cache_set *c = container_of(cl, struct cache_set, cl); 1578 struct cache *ca; 1579 unsigned int i; 1580 1581 debugfs_remove(c->debug); 1582 1583 bch_open_buckets_free(c); 1584 bch_btree_cache_free(c); 1585 bch_journal_free(c); 1586 1587 mutex_lock(&bch_register_lock); 1588 for_each_cache(ca, c, i) 1589 if (ca) { 1590 ca->set = NULL; 1591 c->cache[ca->sb.nr_this_dev] = NULL; 1592 kobject_put(&ca->kobj); 1593 } 1594 1595 bch_bset_sort_state_free(&c->sort); 1596 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1597 1598 if (c->moving_gc_wq) 1599 destroy_workqueue(c->moving_gc_wq); 1600 bioset_exit(&c->bio_split); 1601 mempool_exit(&c->fill_iter); 1602 mempool_exit(&c->bio_meta); 1603 mempool_exit(&c->search); 1604 kfree(c->devices); 1605 1606 list_del(&c->list); 1607 mutex_unlock(&bch_register_lock); 1608 1609 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1610 wake_up(&unregister_wait); 1611 1612 closure_debug_destroy(&c->cl); 1613 kobject_put(&c->kobj); 1614 } 1615 1616 static void cache_set_flush(struct closure *cl) 1617 { 1618 struct cache_set *c = container_of(cl, struct cache_set, caching); 1619 struct cache *ca; 1620 struct btree *b; 1621 unsigned int i; 1622 1623 bch_cache_accounting_destroy(&c->accounting); 1624 1625 kobject_put(&c->internal); 1626 kobject_del(&c->kobj); 1627 1628 if (!IS_ERR_OR_NULL(c->gc_thread)) 1629 kthread_stop(c->gc_thread); 1630 1631 if (!IS_ERR_OR_NULL(c->root)) 1632 list_add(&c->root->list, &c->btree_cache); 1633 1634 /* 1635 * Avoid flushing cached nodes if cache set is retiring 1636 * due to too many I/O errors detected. 1637 */ 1638 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1639 list_for_each_entry(b, &c->btree_cache, list) { 1640 mutex_lock(&b->write_lock); 1641 if (btree_node_dirty(b)) 1642 __bch_btree_node_write(b, NULL); 1643 mutex_unlock(&b->write_lock); 1644 } 1645 1646 for_each_cache(ca, c, i) 1647 if (ca->alloc_thread) 1648 kthread_stop(ca->alloc_thread); 1649 1650 if (c->journal.cur) { 1651 cancel_delayed_work_sync(&c->journal.work); 1652 /* flush last journal entry if needed */ 1653 c->journal.work.work.func(&c->journal.work.work); 1654 } 1655 1656 closure_return(cl); 1657 } 1658 1659 /* 1660 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1661 * cache set is unregistering due to too many I/O errors. In this condition, 1662 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1663 * value and whether the broken cache has dirty data: 1664 * 1665 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1666 * BCH_CACHED_STOP_AUTO 0 NO 1667 * BCH_CACHED_STOP_AUTO 1 YES 1668 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1669 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1670 * 1671 * The expected behavior is, if stop_when_cache_set_failed is configured to 1672 * "auto" via sysfs interface, the bcache device will not be stopped if the 1673 * backing device is clean on the broken cache device. 1674 */ 1675 static void conditional_stop_bcache_device(struct cache_set *c, 1676 struct bcache_device *d, 1677 struct cached_dev *dc) 1678 { 1679 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1680 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1681 d->disk->disk_name, c->sb.set_uuid); 1682 bcache_device_stop(d); 1683 } else if (atomic_read(&dc->has_dirty)) { 1684 /* 1685 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1686 * and dc->has_dirty == 1 1687 */ 1688 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1689 d->disk->disk_name); 1690 /* 1691 * There might be a small time gap that cache set is 1692 * released but bcache device is not. Inside this time 1693 * gap, regular I/O requests will directly go into 1694 * backing device as no cache set attached to. This 1695 * behavior may also introduce potential inconsistence 1696 * data in writeback mode while cache is dirty. 1697 * Therefore before calling bcache_device_stop() due 1698 * to a broken cache device, dc->io_disable should be 1699 * explicitly set to true. 1700 */ 1701 dc->io_disable = true; 1702 /* make others know io_disable is true earlier */ 1703 smp_mb(); 1704 bcache_device_stop(d); 1705 } else { 1706 /* 1707 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1708 * and dc->has_dirty == 0 1709 */ 1710 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1711 d->disk->disk_name); 1712 } 1713 } 1714 1715 static void __cache_set_unregister(struct closure *cl) 1716 { 1717 struct cache_set *c = container_of(cl, struct cache_set, caching); 1718 struct cached_dev *dc; 1719 struct bcache_device *d; 1720 size_t i; 1721 1722 mutex_lock(&bch_register_lock); 1723 1724 for (i = 0; i < c->devices_max_used; i++) { 1725 d = c->devices[i]; 1726 if (!d) 1727 continue; 1728 1729 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1730 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1731 dc = container_of(d, struct cached_dev, disk); 1732 bch_cached_dev_detach(dc); 1733 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1734 conditional_stop_bcache_device(c, d, dc); 1735 } else { 1736 bcache_device_stop(d); 1737 } 1738 } 1739 1740 mutex_unlock(&bch_register_lock); 1741 1742 continue_at(cl, cache_set_flush, system_wq); 1743 } 1744 1745 void bch_cache_set_stop(struct cache_set *c) 1746 { 1747 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1748 /* closure_fn set to __cache_set_unregister() */ 1749 closure_queue(&c->caching); 1750 } 1751 1752 void bch_cache_set_unregister(struct cache_set *c) 1753 { 1754 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1755 bch_cache_set_stop(c); 1756 } 1757 1758 #define alloc_bucket_pages(gfp, c) \ 1759 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1760 1761 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1762 { 1763 int iter_size; 1764 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1765 1766 if (!c) 1767 return NULL; 1768 1769 __module_get(THIS_MODULE); 1770 closure_init(&c->cl, NULL); 1771 set_closure_fn(&c->cl, cache_set_free, system_wq); 1772 1773 closure_init(&c->caching, &c->cl); 1774 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1775 1776 /* Maybe create continue_at_noreturn() and use it here? */ 1777 closure_set_stopped(&c->cl); 1778 closure_put(&c->cl); 1779 1780 kobject_init(&c->kobj, &bch_cache_set_ktype); 1781 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1782 1783 bch_cache_accounting_init(&c->accounting, &c->cl); 1784 1785 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1786 c->sb.block_size = sb->block_size; 1787 c->sb.bucket_size = sb->bucket_size; 1788 c->sb.nr_in_set = sb->nr_in_set; 1789 c->sb.last_mount = sb->last_mount; 1790 c->bucket_bits = ilog2(sb->bucket_size); 1791 c->block_bits = ilog2(sb->block_size); 1792 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1793 c->devices_max_used = 0; 1794 atomic_set(&c->attached_dev_nr, 0); 1795 c->btree_pages = bucket_pages(c); 1796 if (c->btree_pages > BTREE_MAX_PAGES) 1797 c->btree_pages = max_t(int, c->btree_pages / 4, 1798 BTREE_MAX_PAGES); 1799 1800 sema_init(&c->sb_write_mutex, 1); 1801 mutex_init(&c->bucket_lock); 1802 init_waitqueue_head(&c->btree_cache_wait); 1803 spin_lock_init(&c->btree_cannibalize_lock); 1804 init_waitqueue_head(&c->bucket_wait); 1805 init_waitqueue_head(&c->gc_wait); 1806 sema_init(&c->uuid_write_mutex, 1); 1807 1808 spin_lock_init(&c->btree_gc_time.lock); 1809 spin_lock_init(&c->btree_split_time.lock); 1810 spin_lock_init(&c->btree_read_time.lock); 1811 1812 bch_moving_init_cache_set(c); 1813 1814 INIT_LIST_HEAD(&c->list); 1815 INIT_LIST_HEAD(&c->cached_devs); 1816 INIT_LIST_HEAD(&c->btree_cache); 1817 INIT_LIST_HEAD(&c->btree_cache_freeable); 1818 INIT_LIST_HEAD(&c->btree_cache_freed); 1819 INIT_LIST_HEAD(&c->data_buckets); 1820 1821 iter_size = (sb->bucket_size / sb->block_size + 1) * 1822 sizeof(struct btree_iter_set); 1823 1824 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1825 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1826 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1827 sizeof(struct bbio) + sizeof(struct bio_vec) * 1828 bucket_pages(c)) || 1829 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1830 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1831 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1832 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1833 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1834 WQ_MEM_RECLAIM, 0)) || 1835 bch_journal_alloc(c) || 1836 bch_btree_cache_alloc(c) || 1837 bch_open_buckets_alloc(c) || 1838 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1839 goto err; 1840 1841 c->congested_read_threshold_us = 2000; 1842 c->congested_write_threshold_us = 20000; 1843 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1844 c->idle_max_writeback_rate_enabled = 1; 1845 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1846 1847 return c; 1848 err: 1849 bch_cache_set_unregister(c); 1850 return NULL; 1851 } 1852 1853 static int run_cache_set(struct cache_set *c) 1854 { 1855 const char *err = "cannot allocate memory"; 1856 struct cached_dev *dc, *t; 1857 struct cache *ca; 1858 struct closure cl; 1859 unsigned int i; 1860 LIST_HEAD(journal); 1861 struct journal_replay *l; 1862 1863 closure_init_stack(&cl); 1864 1865 for_each_cache(ca, c, i) 1866 c->nbuckets += ca->sb.nbuckets; 1867 set_gc_sectors(c); 1868 1869 if (CACHE_SYNC(&c->sb)) { 1870 struct bkey *k; 1871 struct jset *j; 1872 1873 err = "cannot allocate memory for journal"; 1874 if (bch_journal_read(c, &journal)) 1875 goto err; 1876 1877 pr_debug("btree_journal_read() done"); 1878 1879 err = "no journal entries found"; 1880 if (list_empty(&journal)) 1881 goto err; 1882 1883 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1884 1885 err = "IO error reading priorities"; 1886 for_each_cache(ca, c, i) { 1887 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev])) 1888 goto err; 1889 } 1890 1891 /* 1892 * If prio_read() fails it'll call cache_set_error and we'll 1893 * tear everything down right away, but if we perhaps checked 1894 * sooner we could avoid journal replay. 1895 */ 1896 1897 k = &j->btree_root; 1898 1899 err = "bad btree root"; 1900 if (__bch_btree_ptr_invalid(c, k)) 1901 goto err; 1902 1903 err = "error reading btree root"; 1904 c->root = bch_btree_node_get(c, NULL, k, 1905 j->btree_level, 1906 true, NULL); 1907 if (IS_ERR_OR_NULL(c->root)) 1908 goto err; 1909 1910 list_del_init(&c->root->list); 1911 rw_unlock(true, c->root); 1912 1913 err = uuid_read(c, j, &cl); 1914 if (err) 1915 goto err; 1916 1917 err = "error in recovery"; 1918 if (bch_btree_check(c)) 1919 goto err; 1920 1921 bch_journal_mark(c, &journal); 1922 bch_initial_gc_finish(c); 1923 pr_debug("btree_check() done"); 1924 1925 /* 1926 * bcache_journal_next() can't happen sooner, or 1927 * btree_gc_finish() will give spurious errors about last_gc > 1928 * gc_gen - this is a hack but oh well. 1929 */ 1930 bch_journal_next(&c->journal); 1931 1932 err = "error starting allocator thread"; 1933 for_each_cache(ca, c, i) 1934 if (bch_cache_allocator_start(ca)) 1935 goto err; 1936 1937 /* 1938 * First place it's safe to allocate: btree_check() and 1939 * btree_gc_finish() have to run before we have buckets to 1940 * allocate, and bch_bucket_alloc_set() might cause a journal 1941 * entry to be written so bcache_journal_next() has to be called 1942 * first. 1943 * 1944 * If the uuids were in the old format we have to rewrite them 1945 * before the next journal entry is written: 1946 */ 1947 if (j->version < BCACHE_JSET_VERSION_UUID) 1948 __uuid_write(c); 1949 1950 err = "bcache: replay journal failed"; 1951 if (bch_journal_replay(c, &journal)) 1952 goto err; 1953 } else { 1954 pr_notice("invalidating existing data"); 1955 1956 for_each_cache(ca, c, i) { 1957 unsigned int j; 1958 1959 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1960 2, SB_JOURNAL_BUCKETS); 1961 1962 for (j = 0; j < ca->sb.keys; j++) 1963 ca->sb.d[j] = ca->sb.first_bucket + j; 1964 } 1965 1966 bch_initial_gc_finish(c); 1967 1968 err = "error starting allocator thread"; 1969 for_each_cache(ca, c, i) 1970 if (bch_cache_allocator_start(ca)) 1971 goto err; 1972 1973 mutex_lock(&c->bucket_lock); 1974 for_each_cache(ca, c, i) 1975 bch_prio_write(ca, true); 1976 mutex_unlock(&c->bucket_lock); 1977 1978 err = "cannot allocate new UUID bucket"; 1979 if (__uuid_write(c)) 1980 goto err; 1981 1982 err = "cannot allocate new btree root"; 1983 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1984 if (IS_ERR_OR_NULL(c->root)) 1985 goto err; 1986 1987 mutex_lock(&c->root->write_lock); 1988 bkey_copy_key(&c->root->key, &MAX_KEY); 1989 bch_btree_node_write(c->root, &cl); 1990 mutex_unlock(&c->root->write_lock); 1991 1992 bch_btree_set_root(c->root); 1993 rw_unlock(true, c->root); 1994 1995 /* 1996 * We don't want to write the first journal entry until 1997 * everything is set up - fortunately journal entries won't be 1998 * written until the SET_CACHE_SYNC() here: 1999 */ 2000 SET_CACHE_SYNC(&c->sb, true); 2001 2002 bch_journal_next(&c->journal); 2003 bch_journal_meta(c, &cl); 2004 } 2005 2006 err = "error starting gc thread"; 2007 if (bch_gc_thread_start(c)) 2008 goto err; 2009 2010 closure_sync(&cl); 2011 c->sb.last_mount = (u32)ktime_get_real_seconds(); 2012 bcache_write_super(c); 2013 2014 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2015 bch_cached_dev_attach(dc, c, NULL); 2016 2017 flash_devs_run(c); 2018 2019 set_bit(CACHE_SET_RUNNING, &c->flags); 2020 return 0; 2021 err: 2022 while (!list_empty(&journal)) { 2023 l = list_first_entry(&journal, struct journal_replay, list); 2024 list_del(&l->list); 2025 kfree(l); 2026 } 2027 2028 closure_sync(&cl); 2029 2030 bch_cache_set_error(c, "%s", err); 2031 2032 return -EIO; 2033 } 2034 2035 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 2036 { 2037 return ca->sb.block_size == c->sb.block_size && 2038 ca->sb.bucket_size == c->sb.bucket_size && 2039 ca->sb.nr_in_set == c->sb.nr_in_set; 2040 } 2041 2042 static const char *register_cache_set(struct cache *ca) 2043 { 2044 char buf[12]; 2045 const char *err = "cannot allocate memory"; 2046 struct cache_set *c; 2047 2048 list_for_each_entry(c, &bch_cache_sets, list) 2049 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 2050 if (c->cache[ca->sb.nr_this_dev]) 2051 return "duplicate cache set member"; 2052 2053 if (!can_attach_cache(ca, c)) 2054 return "cache sb does not match set"; 2055 2056 if (!CACHE_SYNC(&ca->sb)) 2057 SET_CACHE_SYNC(&c->sb, false); 2058 2059 goto found; 2060 } 2061 2062 c = bch_cache_set_alloc(&ca->sb); 2063 if (!c) 2064 return err; 2065 2066 err = "error creating kobject"; 2067 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 2068 kobject_add(&c->internal, &c->kobj, "internal")) 2069 goto err; 2070 2071 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 2072 goto err; 2073 2074 bch_debug_init_cache_set(c); 2075 2076 list_add(&c->list, &bch_cache_sets); 2077 found: 2078 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 2079 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 2080 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 2081 goto err; 2082 2083 if (ca->sb.seq > c->sb.seq) { 2084 c->sb.version = ca->sb.version; 2085 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 2086 c->sb.flags = ca->sb.flags; 2087 c->sb.seq = ca->sb.seq; 2088 pr_debug("set version = %llu", c->sb.version); 2089 } 2090 2091 kobject_get(&ca->kobj); 2092 ca->set = c; 2093 ca->set->cache[ca->sb.nr_this_dev] = ca; 2094 c->cache_by_alloc[c->caches_loaded++] = ca; 2095 2096 if (c->caches_loaded == c->sb.nr_in_set) { 2097 err = "failed to run cache set"; 2098 if (run_cache_set(c) < 0) 2099 goto err; 2100 } 2101 2102 return NULL; 2103 err: 2104 bch_cache_set_unregister(c); 2105 return err; 2106 } 2107 2108 /* Cache device */ 2109 2110 /* When ca->kobj released */ 2111 void bch_cache_release(struct kobject *kobj) 2112 { 2113 struct cache *ca = container_of(kobj, struct cache, kobj); 2114 unsigned int i; 2115 2116 if (ca->set) { 2117 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2118 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2119 } 2120 2121 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2122 kfree(ca->prio_buckets); 2123 vfree(ca->buckets); 2124 2125 free_heap(&ca->heap); 2126 free_fifo(&ca->free_inc); 2127 2128 for (i = 0; i < RESERVE_NR; i++) 2129 free_fifo(&ca->free[i]); 2130 2131 if (ca->sb_disk) 2132 put_page(virt_to_page(ca->sb_disk)); 2133 2134 if (!IS_ERR_OR_NULL(ca->bdev)) 2135 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2136 2137 kfree(ca); 2138 module_put(THIS_MODULE); 2139 } 2140 2141 static int cache_alloc(struct cache *ca) 2142 { 2143 size_t free; 2144 size_t btree_buckets; 2145 struct bucket *b; 2146 int ret = -ENOMEM; 2147 const char *err = NULL; 2148 2149 __module_get(THIS_MODULE); 2150 kobject_init(&ca->kobj, &bch_cache_ktype); 2151 2152 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2153 2154 /* 2155 * when ca->sb.njournal_buckets is not zero, journal exists, 2156 * and in bch_journal_replay(), tree node may split, 2157 * so bucket of RESERVE_BTREE type is needed, 2158 * the worst situation is all journal buckets are valid journal, 2159 * and all the keys need to replay, 2160 * so the number of RESERVE_BTREE type buckets should be as much 2161 * as journal buckets 2162 */ 2163 btree_buckets = ca->sb.njournal_buckets ?: 8; 2164 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2165 if (!free) { 2166 ret = -EPERM; 2167 err = "ca->sb.nbuckets is too small"; 2168 goto err_free; 2169 } 2170 2171 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, 2172 GFP_KERNEL)) { 2173 err = "ca->free[RESERVE_BTREE] alloc failed"; 2174 goto err_btree_alloc; 2175 } 2176 2177 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), 2178 GFP_KERNEL)) { 2179 err = "ca->free[RESERVE_PRIO] alloc failed"; 2180 goto err_prio_alloc; 2181 } 2182 2183 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) { 2184 err = "ca->free[RESERVE_MOVINGGC] alloc failed"; 2185 goto err_movinggc_alloc; 2186 } 2187 2188 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) { 2189 err = "ca->free[RESERVE_NONE] alloc failed"; 2190 goto err_none_alloc; 2191 } 2192 2193 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) { 2194 err = "ca->free_inc alloc failed"; 2195 goto err_free_inc_alloc; 2196 } 2197 2198 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) { 2199 err = "ca->heap alloc failed"; 2200 goto err_heap_alloc; 2201 } 2202 2203 ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2204 ca->sb.nbuckets)); 2205 if (!ca->buckets) { 2206 err = "ca->buckets alloc failed"; 2207 goto err_buckets_alloc; 2208 } 2209 2210 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2211 prio_buckets(ca), 2), 2212 GFP_KERNEL); 2213 if (!ca->prio_buckets) { 2214 err = "ca->prio_buckets alloc failed"; 2215 goto err_prio_buckets_alloc; 2216 } 2217 2218 ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca); 2219 if (!ca->disk_buckets) { 2220 err = "ca->disk_buckets alloc failed"; 2221 goto err_disk_buckets_alloc; 2222 } 2223 2224 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2225 2226 for_each_bucket(b, ca) 2227 atomic_set(&b->pin, 0); 2228 return 0; 2229 2230 err_disk_buckets_alloc: 2231 kfree(ca->prio_buckets); 2232 err_prio_buckets_alloc: 2233 vfree(ca->buckets); 2234 err_buckets_alloc: 2235 free_heap(&ca->heap); 2236 err_heap_alloc: 2237 free_fifo(&ca->free_inc); 2238 err_free_inc_alloc: 2239 free_fifo(&ca->free[RESERVE_NONE]); 2240 err_none_alloc: 2241 free_fifo(&ca->free[RESERVE_MOVINGGC]); 2242 err_movinggc_alloc: 2243 free_fifo(&ca->free[RESERVE_PRIO]); 2244 err_prio_alloc: 2245 free_fifo(&ca->free[RESERVE_BTREE]); 2246 err_btree_alloc: 2247 err_free: 2248 module_put(THIS_MODULE); 2249 if (err) 2250 pr_notice("error %s: %s", ca->cache_dev_name, err); 2251 return ret; 2252 } 2253 2254 static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk, 2255 struct block_device *bdev, struct cache *ca) 2256 { 2257 const char *err = NULL; /* must be set for any error case */ 2258 int ret = 0; 2259 2260 bdevname(bdev, ca->cache_dev_name); 2261 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2262 ca->bdev = bdev; 2263 ca->bdev->bd_holder = ca; 2264 ca->sb_disk = sb_disk; 2265 2266 if (blk_queue_discard(bdev_get_queue(bdev))) 2267 ca->discard = CACHE_DISCARD(&ca->sb); 2268 2269 ret = cache_alloc(ca); 2270 if (ret != 0) { 2271 /* 2272 * If we failed here, it means ca->kobj is not initialized yet, 2273 * kobject_put() won't be called and there is no chance to 2274 * call blkdev_put() to bdev in bch_cache_release(). So we 2275 * explicitly call blkdev_put() here. 2276 */ 2277 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2278 if (ret == -ENOMEM) 2279 err = "cache_alloc(): -ENOMEM"; 2280 else if (ret == -EPERM) 2281 err = "cache_alloc(): cache device is too small"; 2282 else 2283 err = "cache_alloc(): unknown error"; 2284 goto err; 2285 } 2286 2287 if (kobject_add(&ca->kobj, 2288 &part_to_dev(bdev->bd_part)->kobj, 2289 "bcache")) { 2290 err = "error calling kobject_add"; 2291 ret = -ENOMEM; 2292 goto out; 2293 } 2294 2295 mutex_lock(&bch_register_lock); 2296 err = register_cache_set(ca); 2297 mutex_unlock(&bch_register_lock); 2298 2299 if (err) { 2300 ret = -ENODEV; 2301 goto out; 2302 } 2303 2304 pr_info("registered cache device %s", ca->cache_dev_name); 2305 2306 out: 2307 kobject_put(&ca->kobj); 2308 2309 err: 2310 if (err) 2311 pr_notice("error %s: %s", ca->cache_dev_name, err); 2312 2313 return ret; 2314 } 2315 2316 /* Global interfaces/init */ 2317 2318 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2319 const char *buffer, size_t size); 2320 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k, 2321 struct kobj_attribute *attr, 2322 const char *buffer, size_t size); 2323 2324 kobj_attribute_write(register, register_bcache); 2325 kobj_attribute_write(register_quiet, register_bcache); 2326 kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup); 2327 2328 static bool bch_is_open_backing(struct block_device *bdev) 2329 { 2330 struct cache_set *c, *tc; 2331 struct cached_dev *dc, *t; 2332 2333 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2334 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2335 if (dc->bdev == bdev) 2336 return true; 2337 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2338 if (dc->bdev == bdev) 2339 return true; 2340 return false; 2341 } 2342 2343 static bool bch_is_open_cache(struct block_device *bdev) 2344 { 2345 struct cache_set *c, *tc; 2346 struct cache *ca; 2347 unsigned int i; 2348 2349 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2350 for_each_cache(ca, c, i) 2351 if (ca->bdev == bdev) 2352 return true; 2353 return false; 2354 } 2355 2356 static bool bch_is_open(struct block_device *bdev) 2357 { 2358 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2359 } 2360 2361 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2362 const char *buffer, size_t size) 2363 { 2364 const char *err; 2365 char *path = NULL; 2366 struct cache_sb *sb; 2367 struct cache_sb_disk *sb_disk; 2368 struct block_device *bdev; 2369 ssize_t ret; 2370 2371 ret = -EBUSY; 2372 err = "failed to reference bcache module"; 2373 if (!try_module_get(THIS_MODULE)) 2374 goto out; 2375 2376 /* For latest state of bcache_is_reboot */ 2377 smp_mb(); 2378 err = "bcache is in reboot"; 2379 if (bcache_is_reboot) 2380 goto out_module_put; 2381 2382 ret = -ENOMEM; 2383 err = "cannot allocate memory"; 2384 path = kstrndup(buffer, size, GFP_KERNEL); 2385 if (!path) 2386 goto out_module_put; 2387 2388 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); 2389 if (!sb) 2390 goto out_free_path; 2391 2392 ret = -EINVAL; 2393 err = "failed to open device"; 2394 bdev = blkdev_get_by_path(strim(path), 2395 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2396 sb); 2397 if (IS_ERR(bdev)) { 2398 if (bdev == ERR_PTR(-EBUSY)) { 2399 bdev = lookup_bdev(strim(path)); 2400 mutex_lock(&bch_register_lock); 2401 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2402 err = "device already registered"; 2403 else 2404 err = "device busy"; 2405 mutex_unlock(&bch_register_lock); 2406 if (!IS_ERR(bdev)) 2407 bdput(bdev); 2408 if (attr == &ksysfs_register_quiet) 2409 goto done; 2410 } 2411 goto out_free_sb; 2412 } 2413 2414 err = "failed to set blocksize"; 2415 if (set_blocksize(bdev, 4096)) 2416 goto out_blkdev_put; 2417 2418 err = read_super(sb, bdev, &sb_disk); 2419 if (err) 2420 goto out_blkdev_put; 2421 2422 err = "failed to register device"; 2423 if (SB_IS_BDEV(sb)) { 2424 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2425 2426 if (!dc) 2427 goto out_put_sb_page; 2428 2429 mutex_lock(&bch_register_lock); 2430 ret = register_bdev(sb, sb_disk, bdev, dc); 2431 mutex_unlock(&bch_register_lock); 2432 /* blkdev_put() will be called in cached_dev_free() */ 2433 if (ret < 0) 2434 goto out_free_sb; 2435 } else { 2436 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2437 2438 if (!ca) 2439 goto out_put_sb_page; 2440 2441 /* blkdev_put() will be called in bch_cache_release() */ 2442 if (register_cache(sb, sb_disk, bdev, ca) != 0) 2443 goto out_free_sb; 2444 } 2445 2446 done: 2447 kfree(sb); 2448 kfree(path); 2449 module_put(THIS_MODULE); 2450 return size; 2451 2452 out_put_sb_page: 2453 put_page(virt_to_page(sb_disk)); 2454 out_blkdev_put: 2455 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); 2456 out_free_sb: 2457 kfree(sb); 2458 out_free_path: 2459 kfree(path); 2460 path = NULL; 2461 out_module_put: 2462 module_put(THIS_MODULE); 2463 out: 2464 pr_info("error %s: %s", path?path:"", err); 2465 return ret; 2466 } 2467 2468 2469 struct pdev { 2470 struct list_head list; 2471 struct cached_dev *dc; 2472 }; 2473 2474 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k, 2475 struct kobj_attribute *attr, 2476 const char *buffer, 2477 size_t size) 2478 { 2479 LIST_HEAD(pending_devs); 2480 ssize_t ret = size; 2481 struct cached_dev *dc, *tdc; 2482 struct pdev *pdev, *tpdev; 2483 struct cache_set *c, *tc; 2484 2485 mutex_lock(&bch_register_lock); 2486 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) { 2487 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL); 2488 if (!pdev) 2489 break; 2490 pdev->dc = dc; 2491 list_add(&pdev->list, &pending_devs); 2492 } 2493 2494 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) { 2495 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) { 2496 char *pdev_set_uuid = pdev->dc->sb.set_uuid; 2497 char *set_uuid = c->sb.uuid; 2498 2499 if (!memcmp(pdev_set_uuid, set_uuid, 16)) { 2500 list_del(&pdev->list); 2501 kfree(pdev); 2502 break; 2503 } 2504 } 2505 } 2506 mutex_unlock(&bch_register_lock); 2507 2508 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) { 2509 pr_info("delete pdev %p", pdev); 2510 list_del(&pdev->list); 2511 bcache_device_stop(&pdev->dc->disk); 2512 kfree(pdev); 2513 } 2514 2515 return ret; 2516 } 2517 2518 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2519 { 2520 if (bcache_is_reboot) 2521 return NOTIFY_DONE; 2522 2523 if (code == SYS_DOWN || 2524 code == SYS_HALT || 2525 code == SYS_POWER_OFF) { 2526 DEFINE_WAIT(wait); 2527 unsigned long start = jiffies; 2528 bool stopped = false; 2529 2530 struct cache_set *c, *tc; 2531 struct cached_dev *dc, *tdc; 2532 2533 mutex_lock(&bch_register_lock); 2534 2535 if (bcache_is_reboot) 2536 goto out; 2537 2538 /* New registration is rejected since now */ 2539 bcache_is_reboot = true; 2540 /* 2541 * Make registering caller (if there is) on other CPU 2542 * core know bcache_is_reboot set to true earlier 2543 */ 2544 smp_mb(); 2545 2546 if (list_empty(&bch_cache_sets) && 2547 list_empty(&uncached_devices)) 2548 goto out; 2549 2550 mutex_unlock(&bch_register_lock); 2551 2552 pr_info("Stopping all devices:"); 2553 2554 /* 2555 * The reason bch_register_lock is not held to call 2556 * bch_cache_set_stop() and bcache_device_stop() is to 2557 * avoid potential deadlock during reboot, because cache 2558 * set or bcache device stopping process will acqurie 2559 * bch_register_lock too. 2560 * 2561 * We are safe here because bcache_is_reboot sets to 2562 * true already, register_bcache() will reject new 2563 * registration now. bcache_is_reboot also makes sure 2564 * bcache_reboot() won't be re-entered on by other thread, 2565 * so there is no race in following list iteration by 2566 * list_for_each_entry_safe(). 2567 */ 2568 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2569 bch_cache_set_stop(c); 2570 2571 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2572 bcache_device_stop(&dc->disk); 2573 2574 2575 /* 2576 * Give an early chance for other kthreads and 2577 * kworkers to stop themselves 2578 */ 2579 schedule(); 2580 2581 /* What's a condition variable? */ 2582 while (1) { 2583 long timeout = start + 10 * HZ - jiffies; 2584 2585 mutex_lock(&bch_register_lock); 2586 stopped = list_empty(&bch_cache_sets) && 2587 list_empty(&uncached_devices); 2588 2589 if (timeout < 0 || stopped) 2590 break; 2591 2592 prepare_to_wait(&unregister_wait, &wait, 2593 TASK_UNINTERRUPTIBLE); 2594 2595 mutex_unlock(&bch_register_lock); 2596 schedule_timeout(timeout); 2597 } 2598 2599 finish_wait(&unregister_wait, &wait); 2600 2601 if (stopped) 2602 pr_info("All devices stopped"); 2603 else 2604 pr_notice("Timeout waiting for devices to be closed"); 2605 out: 2606 mutex_unlock(&bch_register_lock); 2607 } 2608 2609 return NOTIFY_DONE; 2610 } 2611 2612 static struct notifier_block reboot = { 2613 .notifier_call = bcache_reboot, 2614 .priority = INT_MAX, /* before any real devices */ 2615 }; 2616 2617 static void bcache_exit(void) 2618 { 2619 bch_debug_exit(); 2620 bch_request_exit(); 2621 if (bcache_kobj) 2622 kobject_put(bcache_kobj); 2623 if (bcache_wq) 2624 destroy_workqueue(bcache_wq); 2625 if (bch_journal_wq) 2626 destroy_workqueue(bch_journal_wq); 2627 2628 if (bcache_major) 2629 unregister_blkdev(bcache_major, "bcache"); 2630 unregister_reboot_notifier(&reboot); 2631 mutex_destroy(&bch_register_lock); 2632 } 2633 2634 /* Check and fixup module parameters */ 2635 static void check_module_parameters(void) 2636 { 2637 if (bch_cutoff_writeback_sync == 0) 2638 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC; 2639 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) { 2640 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u", 2641 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX); 2642 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX; 2643 } 2644 2645 if (bch_cutoff_writeback == 0) 2646 bch_cutoff_writeback = CUTOFF_WRITEBACK; 2647 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) { 2648 pr_warn("set bch_cutoff_writeback (%u) to max value %u", 2649 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX); 2650 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX; 2651 } 2652 2653 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) { 2654 pr_warn("set bch_cutoff_writeback (%u) to %u", 2655 bch_cutoff_writeback, bch_cutoff_writeback_sync); 2656 bch_cutoff_writeback = bch_cutoff_writeback_sync; 2657 } 2658 } 2659 2660 static int __init bcache_init(void) 2661 { 2662 static const struct attribute *files[] = { 2663 &ksysfs_register.attr, 2664 &ksysfs_register_quiet.attr, 2665 &ksysfs_pendings_cleanup.attr, 2666 NULL 2667 }; 2668 2669 check_module_parameters(); 2670 2671 mutex_init(&bch_register_lock); 2672 init_waitqueue_head(&unregister_wait); 2673 register_reboot_notifier(&reboot); 2674 2675 bcache_major = register_blkdev(0, "bcache"); 2676 if (bcache_major < 0) { 2677 unregister_reboot_notifier(&reboot); 2678 mutex_destroy(&bch_register_lock); 2679 return bcache_major; 2680 } 2681 2682 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); 2683 if (!bcache_wq) 2684 goto err; 2685 2686 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); 2687 if (!bch_journal_wq) 2688 goto err; 2689 2690 bcache_kobj = kobject_create_and_add("bcache", fs_kobj); 2691 if (!bcache_kobj) 2692 goto err; 2693 2694 if (bch_request_init() || 2695 sysfs_create_files(bcache_kobj, files)) 2696 goto err; 2697 2698 bch_debug_init(); 2699 closure_debug_init(); 2700 2701 bcache_is_reboot = false; 2702 2703 return 0; 2704 err: 2705 bcache_exit(); 2706 return -ENOMEM; 2707 } 2708 2709 /* 2710 * Module hooks 2711 */ 2712 module_exit(bcache_exit); 2713 module_init(bcache_init); 2714 2715 module_param(bch_cutoff_writeback, uint, 0); 2716 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback"); 2717 2718 module_param(bch_cutoff_writeback_sync, uint, 0); 2719 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback"); 2720 2721 MODULE_DESCRIPTION("Bcache: a Linux block layer cache"); 2722 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>"); 2723 MODULE_LICENSE("GPL"); 2724