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/buffer_head.h> 19 #include <linux/debugfs.h> 20 #include <linux/genhd.h> 21 #include <linux/idr.h> 22 #include <linux/kthread.h> 23 #include <linux/module.h> 24 #include <linux/random.h> 25 #include <linux/reboot.h> 26 #include <linux/sysfs.h> 27 28 unsigned int bch_cutoff_writeback; 29 unsigned int bch_cutoff_writeback_sync; 30 31 static const char bcache_magic[] = { 32 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca, 33 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 34 }; 35 36 static const char invalid_uuid[] = { 37 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78, 38 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99 39 }; 40 41 static struct kobject *bcache_kobj; 42 struct mutex bch_register_lock; 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 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 53 /* limitation of partitions number on single bcache device */ 54 #define BCACHE_MINORS 128 55 /* limitation of bcache devices number on single system */ 56 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 57 58 /* Superblock */ 59 60 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 61 struct page **res) 62 { 63 const char *err; 64 struct cache_sb *s; 65 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 66 unsigned int i; 67 68 if (!bh) 69 return "IO error"; 70 71 s = (struct cache_sb *) bh->b_data; 72 73 sb->offset = le64_to_cpu(s->offset); 74 sb->version = le64_to_cpu(s->version); 75 76 memcpy(sb->magic, s->magic, 16); 77 memcpy(sb->uuid, s->uuid, 16); 78 memcpy(sb->set_uuid, s->set_uuid, 16); 79 memcpy(sb->label, s->label, SB_LABEL_SIZE); 80 81 sb->flags = le64_to_cpu(s->flags); 82 sb->seq = le64_to_cpu(s->seq); 83 sb->last_mount = le32_to_cpu(s->last_mount); 84 sb->first_bucket = le16_to_cpu(s->first_bucket); 85 sb->keys = le16_to_cpu(s->keys); 86 87 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 88 sb->d[i] = le64_to_cpu(s->d[i]); 89 90 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 91 sb->version, sb->flags, sb->seq, sb->keys); 92 93 err = "Not a bcache superblock"; 94 if (sb->offset != SB_SECTOR) 95 goto err; 96 97 if (memcmp(sb->magic, bcache_magic, 16)) 98 goto err; 99 100 err = "Too many journal buckets"; 101 if (sb->keys > SB_JOURNAL_BUCKETS) 102 goto err; 103 104 err = "Bad checksum"; 105 if (s->csum != csum_set(s)) 106 goto err; 107 108 err = "Bad UUID"; 109 if (bch_is_zero(sb->uuid, 16)) 110 goto err; 111 112 sb->block_size = le16_to_cpu(s->block_size); 113 114 err = "Superblock block size smaller than device block size"; 115 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 116 goto err; 117 118 switch (sb->version) { 119 case BCACHE_SB_VERSION_BDEV: 120 sb->data_offset = BDEV_DATA_START_DEFAULT; 121 break; 122 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 123 sb->data_offset = le64_to_cpu(s->data_offset); 124 125 err = "Bad data offset"; 126 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 127 goto err; 128 129 break; 130 case BCACHE_SB_VERSION_CDEV: 131 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 132 sb->nbuckets = le64_to_cpu(s->nbuckets); 133 sb->bucket_size = le16_to_cpu(s->bucket_size); 134 135 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 136 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 137 138 err = "Too many buckets"; 139 if (sb->nbuckets > LONG_MAX) 140 goto err; 141 142 err = "Not enough buckets"; 143 if (sb->nbuckets < 1 << 7) 144 goto err; 145 146 err = "Bad block/bucket size"; 147 if (!is_power_of_2(sb->block_size) || 148 sb->block_size > PAGE_SECTORS || 149 !is_power_of_2(sb->bucket_size) || 150 sb->bucket_size < PAGE_SECTORS) 151 goto err; 152 153 err = "Invalid superblock: device too small"; 154 if (get_capacity(bdev->bd_disk) < 155 sb->bucket_size * sb->nbuckets) 156 goto err; 157 158 err = "Bad UUID"; 159 if (bch_is_zero(sb->set_uuid, 16)) 160 goto err; 161 162 err = "Bad cache device number in set"; 163 if (!sb->nr_in_set || 164 sb->nr_in_set <= sb->nr_this_dev || 165 sb->nr_in_set > MAX_CACHES_PER_SET) 166 goto err; 167 168 err = "Journal buckets not sequential"; 169 for (i = 0; i < sb->keys; i++) 170 if (sb->d[i] != sb->first_bucket + i) 171 goto err; 172 173 err = "Too many journal buckets"; 174 if (sb->first_bucket + sb->keys > sb->nbuckets) 175 goto err; 176 177 err = "Invalid superblock: first bucket comes before end of super"; 178 if (sb->first_bucket * sb->bucket_size < 16) 179 goto err; 180 181 break; 182 default: 183 err = "Unsupported superblock version"; 184 goto err; 185 } 186 187 sb->last_mount = (u32)ktime_get_real_seconds(); 188 err = NULL; 189 190 get_page(bh->b_page); 191 *res = bh->b_page; 192 err: 193 put_bh(bh); 194 return err; 195 } 196 197 static void write_bdev_super_endio(struct bio *bio) 198 { 199 struct cached_dev *dc = bio->bi_private; 200 /* XXX: error checking */ 201 202 closure_put(&dc->sb_write); 203 } 204 205 static void __write_super(struct cache_sb *sb, struct bio *bio) 206 { 207 struct cache_sb *out = page_address(bio_first_page_all(bio)); 208 unsigned int i; 209 210 bio->bi_iter.bi_sector = SB_SECTOR; 211 bio->bi_iter.bi_size = SB_SIZE; 212 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 213 bch_bio_map(bio, NULL); 214 215 out->offset = cpu_to_le64(sb->offset); 216 out->version = cpu_to_le64(sb->version); 217 218 memcpy(out->uuid, sb->uuid, 16); 219 memcpy(out->set_uuid, sb->set_uuid, 16); 220 memcpy(out->label, sb->label, SB_LABEL_SIZE); 221 222 out->flags = cpu_to_le64(sb->flags); 223 out->seq = cpu_to_le64(sb->seq); 224 225 out->last_mount = cpu_to_le32(sb->last_mount); 226 out->first_bucket = cpu_to_le16(sb->first_bucket); 227 out->keys = cpu_to_le16(sb->keys); 228 229 for (i = 0; i < sb->keys; i++) 230 out->d[i] = cpu_to_le64(sb->d[i]); 231 232 out->csum = csum_set(out); 233 234 pr_debug("ver %llu, flags %llu, seq %llu", 235 sb->version, sb->flags, sb->seq); 236 237 submit_bio(bio); 238 } 239 240 static void bch_write_bdev_super_unlock(struct closure *cl) 241 { 242 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 243 244 up(&dc->sb_write_mutex); 245 } 246 247 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 248 { 249 struct closure *cl = &dc->sb_write; 250 struct bio *bio = &dc->sb_bio; 251 252 down(&dc->sb_write_mutex); 253 closure_init(cl, parent); 254 255 bio_reset(bio); 256 bio_set_dev(bio, dc->bdev); 257 bio->bi_end_io = write_bdev_super_endio; 258 bio->bi_private = dc; 259 260 closure_get(cl); 261 /* I/O request sent to backing device */ 262 __write_super(&dc->sb, bio); 263 264 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 265 } 266 267 static void write_super_endio(struct bio *bio) 268 { 269 struct cache *ca = bio->bi_private; 270 271 /* is_read = 0 */ 272 bch_count_io_errors(ca, bio->bi_status, 0, 273 "writing superblock"); 274 closure_put(&ca->set->sb_write); 275 } 276 277 static void bcache_write_super_unlock(struct closure *cl) 278 { 279 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 280 281 up(&c->sb_write_mutex); 282 } 283 284 void bcache_write_super(struct cache_set *c) 285 { 286 struct closure *cl = &c->sb_write; 287 struct cache *ca; 288 unsigned int i; 289 290 down(&c->sb_write_mutex); 291 closure_init(cl, &c->cl); 292 293 c->sb.seq++; 294 295 for_each_cache(ca, c, i) { 296 struct bio *bio = &ca->sb_bio; 297 298 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 299 ca->sb.seq = c->sb.seq; 300 ca->sb.last_mount = c->sb.last_mount; 301 302 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 303 304 bio_reset(bio); 305 bio_set_dev(bio, ca->bdev); 306 bio->bi_end_io = write_super_endio; 307 bio->bi_private = ca; 308 309 closure_get(cl); 310 __write_super(&ca->sb, bio); 311 } 312 313 closure_return_with_destructor(cl, bcache_write_super_unlock); 314 } 315 316 /* UUID io */ 317 318 static void uuid_endio(struct bio *bio) 319 { 320 struct closure *cl = bio->bi_private; 321 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 322 323 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 324 bch_bbio_free(bio, c); 325 closure_put(cl); 326 } 327 328 static void uuid_io_unlock(struct closure *cl) 329 { 330 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 331 332 up(&c->uuid_write_mutex); 333 } 334 335 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 336 struct bkey *k, struct closure *parent) 337 { 338 struct closure *cl = &c->uuid_write; 339 struct uuid_entry *u; 340 unsigned int i; 341 char buf[80]; 342 343 BUG_ON(!parent); 344 down(&c->uuid_write_mutex); 345 closure_init(cl, parent); 346 347 for (i = 0; i < KEY_PTRS(k); i++) { 348 struct bio *bio = bch_bbio_alloc(c); 349 350 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 351 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 352 353 bio->bi_end_io = uuid_endio; 354 bio->bi_private = cl; 355 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 356 bch_bio_map(bio, c->uuids); 357 358 bch_submit_bbio(bio, c, k, i); 359 360 if (op != REQ_OP_WRITE) 361 break; 362 } 363 364 bch_extent_to_text(buf, sizeof(buf), k); 365 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 366 367 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 368 if (!bch_is_zero(u->uuid, 16)) 369 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 370 u - c->uuids, u->uuid, u->label, 371 u->first_reg, u->last_reg, u->invalidated); 372 373 closure_return_with_destructor(cl, uuid_io_unlock); 374 } 375 376 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 377 { 378 struct bkey *k = &j->uuid_bucket; 379 380 if (__bch_btree_ptr_invalid(c, k)) 381 return "bad uuid pointer"; 382 383 bkey_copy(&c->uuid_bucket, k); 384 uuid_io(c, REQ_OP_READ, 0, k, cl); 385 386 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 387 struct uuid_entry_v0 *u0 = (void *) c->uuids; 388 struct uuid_entry *u1 = (void *) c->uuids; 389 int i; 390 391 closure_sync(cl); 392 393 /* 394 * Since the new uuid entry is bigger than the old, we have to 395 * convert starting at the highest memory address and work down 396 * in order to do it in place 397 */ 398 399 for (i = c->nr_uuids - 1; 400 i >= 0; 401 --i) { 402 memcpy(u1[i].uuid, u0[i].uuid, 16); 403 memcpy(u1[i].label, u0[i].label, 32); 404 405 u1[i].first_reg = u0[i].first_reg; 406 u1[i].last_reg = u0[i].last_reg; 407 u1[i].invalidated = u0[i].invalidated; 408 409 u1[i].flags = 0; 410 u1[i].sectors = 0; 411 } 412 } 413 414 return NULL; 415 } 416 417 static int __uuid_write(struct cache_set *c) 418 { 419 BKEY_PADDED(key) k; 420 struct closure cl; 421 struct cache *ca; 422 423 closure_init_stack(&cl); 424 lockdep_assert_held(&bch_register_lock); 425 426 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 427 return 1; 428 429 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 430 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 431 closure_sync(&cl); 432 433 /* Only one bucket used for uuid write */ 434 ca = PTR_CACHE(c, &k.key, 0); 435 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written); 436 437 bkey_copy(&c->uuid_bucket, &k.key); 438 bkey_put(c, &k.key); 439 return 0; 440 } 441 442 int bch_uuid_write(struct cache_set *c) 443 { 444 int ret = __uuid_write(c); 445 446 if (!ret) 447 bch_journal_meta(c, NULL); 448 449 return ret; 450 } 451 452 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 453 { 454 struct uuid_entry *u; 455 456 for (u = c->uuids; 457 u < c->uuids + c->nr_uuids; u++) 458 if (!memcmp(u->uuid, uuid, 16)) 459 return u; 460 461 return NULL; 462 } 463 464 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 465 { 466 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 467 468 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(ca->set, 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 int 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 != 612 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 613 pr_warn("bad csum reading priorities"); 614 615 if (p->magic != pset_magic(&ca->sb)) 616 pr_warn("bad magic reading priorities"); 617 618 bucket = p->next_bucket; 619 d = p->data; 620 } 621 622 b->prio = le16_to_cpu(d->prio); 623 b->gen = b->last_gc = d->gen; 624 } 625 } 626 627 /* Bcache device */ 628 629 static int open_dev(struct block_device *b, fmode_t mode) 630 { 631 struct bcache_device *d = b->bd_disk->private_data; 632 633 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 634 return -ENXIO; 635 636 closure_get(&d->cl); 637 return 0; 638 } 639 640 static void release_dev(struct gendisk *b, fmode_t mode) 641 { 642 struct bcache_device *d = b->private_data; 643 644 closure_put(&d->cl); 645 } 646 647 static int ioctl_dev(struct block_device *b, fmode_t mode, 648 unsigned int cmd, unsigned long arg) 649 { 650 struct bcache_device *d = b->bd_disk->private_data; 651 652 return d->ioctl(d, mode, cmd, arg); 653 } 654 655 static const struct block_device_operations bcache_ops = { 656 .open = open_dev, 657 .release = release_dev, 658 .ioctl = ioctl_dev, 659 .owner = THIS_MODULE, 660 }; 661 662 void bcache_device_stop(struct bcache_device *d) 663 { 664 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 665 /* 666 * closure_fn set to 667 * - cached device: cached_dev_flush() 668 * - flash dev: flash_dev_flush() 669 */ 670 closure_queue(&d->cl); 671 } 672 673 static void bcache_device_unlink(struct bcache_device *d) 674 { 675 lockdep_assert_held(&bch_register_lock); 676 677 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 678 unsigned int i; 679 struct cache *ca; 680 681 sysfs_remove_link(&d->c->kobj, d->name); 682 sysfs_remove_link(&d->kobj, "cache"); 683 684 for_each_cache(ca, d->c, i) 685 bd_unlink_disk_holder(ca->bdev, d->disk); 686 } 687 } 688 689 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 690 const char *name) 691 { 692 unsigned int i; 693 struct cache *ca; 694 695 for_each_cache(ca, d->c, i) 696 bd_link_disk_holder(ca->bdev, d->disk); 697 698 snprintf(d->name, BCACHEDEVNAME_SIZE, 699 "%s%u", name, d->id); 700 701 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 702 sysfs_create_link(&c->kobj, &d->kobj, d->name), 703 "Couldn't create device <-> cache set symlinks"); 704 705 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 706 } 707 708 static void bcache_device_detach(struct bcache_device *d) 709 { 710 lockdep_assert_held(&bch_register_lock); 711 712 atomic_dec(&d->c->attached_dev_nr); 713 714 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 715 struct uuid_entry *u = d->c->uuids + d->id; 716 717 SET_UUID_FLASH_ONLY(u, 0); 718 memcpy(u->uuid, invalid_uuid, 16); 719 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 720 bch_uuid_write(d->c); 721 } 722 723 bcache_device_unlink(d); 724 725 d->c->devices[d->id] = NULL; 726 closure_put(&d->c->caching); 727 d->c = NULL; 728 } 729 730 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 731 unsigned int id) 732 { 733 d->id = id; 734 d->c = c; 735 c->devices[id] = d; 736 737 if (id >= c->devices_max_used) 738 c->devices_max_used = id + 1; 739 740 closure_get(&c->caching); 741 } 742 743 static inline int first_minor_to_idx(int first_minor) 744 { 745 return (first_minor/BCACHE_MINORS); 746 } 747 748 static inline int idx_to_first_minor(int idx) 749 { 750 return (idx * BCACHE_MINORS); 751 } 752 753 static void bcache_device_free(struct bcache_device *d) 754 { 755 lockdep_assert_held(&bch_register_lock); 756 757 pr_info("%s stopped", d->disk->disk_name); 758 759 if (d->c) 760 bcache_device_detach(d); 761 if (d->disk && d->disk->flags & GENHD_FL_UP) 762 del_gendisk(d->disk); 763 if (d->disk && d->disk->queue) 764 blk_cleanup_queue(d->disk->queue); 765 if (d->disk) { 766 ida_simple_remove(&bcache_device_idx, 767 first_minor_to_idx(d->disk->first_minor)); 768 put_disk(d->disk); 769 } 770 771 bioset_exit(&d->bio_split); 772 kvfree(d->full_dirty_stripes); 773 kvfree(d->stripe_sectors_dirty); 774 775 closure_debug_destroy(&d->cl); 776 } 777 778 static int bcache_device_init(struct bcache_device *d, unsigned int block_size, 779 sector_t sectors) 780 { 781 struct request_queue *q; 782 const size_t max_stripes = min_t(size_t, INT_MAX, 783 SIZE_MAX / sizeof(atomic_t)); 784 size_t n; 785 int idx; 786 787 if (!d->stripe_size) 788 d->stripe_size = 1 << 31; 789 790 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 791 792 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 793 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 794 (unsigned int)d->nr_stripes); 795 return -ENOMEM; 796 } 797 798 n = d->nr_stripes * sizeof(atomic_t); 799 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 800 if (!d->stripe_sectors_dirty) 801 return -ENOMEM; 802 803 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 804 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 805 if (!d->full_dirty_stripes) 806 return -ENOMEM; 807 808 idx = ida_simple_get(&bcache_device_idx, 0, 809 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 810 if (idx < 0) 811 return idx; 812 813 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 814 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) 815 goto err; 816 817 d->disk = alloc_disk(BCACHE_MINORS); 818 if (!d->disk) 819 goto err; 820 821 set_capacity(d->disk, sectors); 822 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 823 824 d->disk->major = bcache_major; 825 d->disk->first_minor = idx_to_first_minor(idx); 826 d->disk->fops = &bcache_ops; 827 d->disk->private_data = d; 828 829 q = blk_alloc_queue(GFP_KERNEL); 830 if (!q) 831 return -ENOMEM; 832 833 blk_queue_make_request(q, NULL); 834 d->disk->queue = q; 835 q->queuedata = d; 836 q->backing_dev_info->congested_data = d; 837 q->limits.max_hw_sectors = UINT_MAX; 838 q->limits.max_sectors = UINT_MAX; 839 q->limits.max_segment_size = UINT_MAX; 840 q->limits.max_segments = BIO_MAX_PAGES; 841 blk_queue_max_discard_sectors(q, UINT_MAX); 842 q->limits.discard_granularity = 512; 843 q->limits.io_min = block_size; 844 q->limits.logical_block_size = block_size; 845 q->limits.physical_block_size = block_size; 846 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 847 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 848 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 849 850 blk_queue_write_cache(q, true, true); 851 852 return 0; 853 854 err: 855 ida_simple_remove(&bcache_device_idx, idx); 856 return -ENOMEM; 857 858 } 859 860 /* Cached device */ 861 862 static void calc_cached_dev_sectors(struct cache_set *c) 863 { 864 uint64_t sectors = 0; 865 struct cached_dev *dc; 866 867 list_for_each_entry(dc, &c->cached_devs, list) 868 sectors += bdev_sectors(dc->bdev); 869 870 c->cached_dev_sectors = sectors; 871 } 872 873 #define BACKING_DEV_OFFLINE_TIMEOUT 5 874 static int cached_dev_status_update(void *arg) 875 { 876 struct cached_dev *dc = arg; 877 struct request_queue *q; 878 879 /* 880 * If this delayed worker is stopping outside, directly quit here. 881 * dc->io_disable might be set via sysfs interface, so check it 882 * here too. 883 */ 884 while (!kthread_should_stop() && !dc->io_disable) { 885 q = bdev_get_queue(dc->bdev); 886 if (blk_queue_dying(q)) 887 dc->offline_seconds++; 888 else 889 dc->offline_seconds = 0; 890 891 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 892 pr_err("%s: device offline for %d seconds", 893 dc->backing_dev_name, 894 BACKING_DEV_OFFLINE_TIMEOUT); 895 pr_err("%s: disable I/O request due to backing " 896 "device offline", dc->disk.name); 897 dc->io_disable = true; 898 /* let others know earlier that io_disable is true */ 899 smp_mb(); 900 bcache_device_stop(&dc->disk); 901 break; 902 } 903 schedule_timeout_interruptible(HZ); 904 } 905 906 wait_for_kthread_stop(); 907 return 0; 908 } 909 910 911 void bch_cached_dev_run(struct cached_dev *dc) 912 { 913 struct bcache_device *d = &dc->disk; 914 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL); 915 char *env[] = { 916 "DRIVER=bcache", 917 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 918 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""), 919 NULL, 920 }; 921 922 if (atomic_xchg(&dc->running, 1)) { 923 kfree(env[1]); 924 kfree(env[2]); 925 kfree(buf); 926 return; 927 } 928 929 if (!d->c && 930 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 931 struct closure cl; 932 933 closure_init_stack(&cl); 934 935 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 936 bch_write_bdev_super(dc, &cl); 937 closure_sync(&cl); 938 } 939 940 add_disk(d->disk); 941 bd_link_disk_holder(dc->bdev, dc->disk.disk); 942 /* 943 * won't show up in the uevent file, use udevadm monitor -e instead 944 * only class / kset properties are persistent 945 */ 946 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 947 kfree(env[1]); 948 kfree(env[2]); 949 kfree(buf); 950 951 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 952 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 953 pr_debug("error creating sysfs link"); 954 955 dc->status_update_thread = kthread_run(cached_dev_status_update, 956 dc, "bcache_status_update"); 957 if (IS_ERR(dc->status_update_thread)) { 958 pr_warn("failed to create bcache_status_update kthread, " 959 "continue to run without monitoring backing " 960 "device status"); 961 } 962 } 963 964 /* 965 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 966 * work dc->writeback_rate_update is running. Wait until the routine 967 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 968 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 969 * seconds, give up waiting here and continue to cancel it too. 970 */ 971 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 972 { 973 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 974 975 do { 976 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 977 &dc->disk.flags)) 978 break; 979 time_out--; 980 schedule_timeout_interruptible(1); 981 } while (time_out > 0); 982 983 if (time_out == 0) 984 pr_warn("give up waiting for dc->writeback_write_update to quit"); 985 986 cancel_delayed_work_sync(&dc->writeback_rate_update); 987 } 988 989 static void cached_dev_detach_finish(struct work_struct *w) 990 { 991 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 992 struct closure cl; 993 994 closure_init_stack(&cl); 995 996 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 997 BUG_ON(refcount_read(&dc->count)); 998 999 mutex_lock(&bch_register_lock); 1000 1001 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1002 cancel_writeback_rate_update_dwork(dc); 1003 1004 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 1005 kthread_stop(dc->writeback_thread); 1006 dc->writeback_thread = NULL; 1007 } 1008 1009 memset(&dc->sb.set_uuid, 0, 16); 1010 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 1011 1012 bch_write_bdev_super(dc, &cl); 1013 closure_sync(&cl); 1014 1015 calc_cached_dev_sectors(dc->disk.c); 1016 bcache_device_detach(&dc->disk); 1017 list_move(&dc->list, &uncached_devices); 1018 1019 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1020 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1021 1022 mutex_unlock(&bch_register_lock); 1023 1024 pr_info("Caching disabled for %s", dc->backing_dev_name); 1025 1026 /* Drop ref we took in cached_dev_detach() */ 1027 closure_put(&dc->disk.cl); 1028 } 1029 1030 void bch_cached_dev_detach(struct cached_dev *dc) 1031 { 1032 lockdep_assert_held(&bch_register_lock); 1033 1034 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1035 return; 1036 1037 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1038 return; 1039 1040 /* 1041 * Block the device from being closed and freed until we're finished 1042 * detaching 1043 */ 1044 closure_get(&dc->disk.cl); 1045 1046 bch_writeback_queue(dc); 1047 1048 cached_dev_put(dc); 1049 } 1050 1051 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1052 uint8_t *set_uuid) 1053 { 1054 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); 1055 struct uuid_entry *u; 1056 struct cached_dev *exist_dc, *t; 1057 1058 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1059 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1060 return -ENOENT; 1061 1062 if (dc->disk.c) { 1063 pr_err("Can't attach %s: already attached", 1064 dc->backing_dev_name); 1065 return -EINVAL; 1066 } 1067 1068 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1069 pr_err("Can't attach %s: shutting down", 1070 dc->backing_dev_name); 1071 return -EINVAL; 1072 } 1073 1074 if (dc->sb.block_size < c->sb.block_size) { 1075 /* Will die */ 1076 pr_err("Couldn't attach %s: block size less than set's block size", 1077 dc->backing_dev_name); 1078 return -EINVAL; 1079 } 1080 1081 /* Check whether already attached */ 1082 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1083 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1084 pr_err("Tried to attach %s but duplicate UUID already attached", 1085 dc->backing_dev_name); 1086 1087 return -EINVAL; 1088 } 1089 } 1090 1091 u = uuid_find(c, dc->sb.uuid); 1092 1093 if (u && 1094 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1095 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1096 memcpy(u->uuid, invalid_uuid, 16); 1097 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 1098 u = NULL; 1099 } 1100 1101 if (!u) { 1102 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1103 pr_err("Couldn't find uuid for %s in set", 1104 dc->backing_dev_name); 1105 return -ENOENT; 1106 } 1107 1108 u = uuid_find_empty(c); 1109 if (!u) { 1110 pr_err("Not caching %s, no room for UUID", 1111 dc->backing_dev_name); 1112 return -EINVAL; 1113 } 1114 } 1115 1116 /* 1117 * Deadlocks since we're called via sysfs... 1118 * sysfs_remove_file(&dc->kobj, &sysfs_attach); 1119 */ 1120 1121 if (bch_is_zero(u->uuid, 16)) { 1122 struct closure cl; 1123 1124 closure_init_stack(&cl); 1125 1126 memcpy(u->uuid, dc->sb.uuid, 16); 1127 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1128 u->first_reg = u->last_reg = rtime; 1129 bch_uuid_write(c); 1130 1131 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1132 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1133 1134 bch_write_bdev_super(dc, &cl); 1135 closure_sync(&cl); 1136 } else { 1137 u->last_reg = rtime; 1138 bch_uuid_write(c); 1139 } 1140 1141 bcache_device_attach(&dc->disk, c, u - c->uuids); 1142 list_move(&dc->list, &c->cached_devs); 1143 calc_cached_dev_sectors(c); 1144 1145 /* 1146 * dc->c must be set before dc->count != 0 - paired with the mb in 1147 * cached_dev_get() 1148 */ 1149 smp_wmb(); 1150 refcount_set(&dc->count, 1); 1151 1152 /* Block writeback thread, but spawn it */ 1153 down_write(&dc->writeback_lock); 1154 if (bch_cached_dev_writeback_start(dc)) { 1155 up_write(&dc->writeback_lock); 1156 return -ENOMEM; 1157 } 1158 1159 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1160 atomic_set(&dc->has_dirty, 1); 1161 bch_writeback_queue(dc); 1162 } 1163 1164 bch_sectors_dirty_init(&dc->disk); 1165 1166 bch_cached_dev_run(dc); 1167 bcache_device_link(&dc->disk, c, "bdev"); 1168 atomic_inc(&c->attached_dev_nr); 1169 1170 /* Allow the writeback thread to proceed */ 1171 up_write(&dc->writeback_lock); 1172 1173 pr_info("Caching %s as %s on set %pU", 1174 dc->backing_dev_name, 1175 dc->disk.disk->disk_name, 1176 dc->disk.c->sb.set_uuid); 1177 return 0; 1178 } 1179 1180 /* when dc->disk.kobj released */ 1181 void bch_cached_dev_release(struct kobject *kobj) 1182 { 1183 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1184 disk.kobj); 1185 kfree(dc); 1186 module_put(THIS_MODULE); 1187 } 1188 1189 static void cached_dev_free(struct closure *cl) 1190 { 1191 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1192 1193 mutex_lock(&bch_register_lock); 1194 1195 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1196 cancel_writeback_rate_update_dwork(dc); 1197 1198 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1199 kthread_stop(dc->writeback_thread); 1200 if (dc->writeback_write_wq) 1201 destroy_workqueue(dc->writeback_write_wq); 1202 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1203 kthread_stop(dc->status_update_thread); 1204 1205 if (atomic_read(&dc->running)) 1206 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1207 bcache_device_free(&dc->disk); 1208 list_del(&dc->list); 1209 1210 mutex_unlock(&bch_register_lock); 1211 1212 if (!IS_ERR_OR_NULL(dc->bdev)) 1213 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1214 1215 wake_up(&unregister_wait); 1216 1217 kobject_put(&dc->disk.kobj); 1218 } 1219 1220 static void cached_dev_flush(struct closure *cl) 1221 { 1222 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1223 struct bcache_device *d = &dc->disk; 1224 1225 mutex_lock(&bch_register_lock); 1226 bcache_device_unlink(d); 1227 mutex_unlock(&bch_register_lock); 1228 1229 bch_cache_accounting_destroy(&dc->accounting); 1230 kobject_del(&d->kobj); 1231 1232 continue_at(cl, cached_dev_free, system_wq); 1233 } 1234 1235 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size) 1236 { 1237 int ret; 1238 struct io *io; 1239 struct request_queue *q = bdev_get_queue(dc->bdev); 1240 1241 __module_get(THIS_MODULE); 1242 INIT_LIST_HEAD(&dc->list); 1243 closure_init(&dc->disk.cl, NULL); 1244 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1245 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1246 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1247 sema_init(&dc->sb_write_mutex, 1); 1248 INIT_LIST_HEAD(&dc->io_lru); 1249 spin_lock_init(&dc->io_lock); 1250 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1251 1252 dc->sequential_cutoff = 4 << 20; 1253 1254 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1255 list_add(&io->lru, &dc->io_lru); 1256 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1257 } 1258 1259 dc->disk.stripe_size = q->limits.io_opt >> 9; 1260 1261 if (dc->disk.stripe_size) 1262 dc->partial_stripes_expensive = 1263 q->limits.raid_partial_stripes_expensive; 1264 1265 ret = bcache_device_init(&dc->disk, block_size, 1266 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1267 if (ret) 1268 return ret; 1269 1270 dc->disk.disk->queue->backing_dev_info->ra_pages = 1271 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1272 q->backing_dev_info->ra_pages); 1273 1274 atomic_set(&dc->io_errors, 0); 1275 dc->io_disable = false; 1276 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1277 /* default to auto */ 1278 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1279 1280 bch_cached_dev_request_init(dc); 1281 bch_cached_dev_writeback_init(dc); 1282 return 0; 1283 } 1284 1285 /* Cached device - bcache superblock */ 1286 1287 static int register_bdev(struct cache_sb *sb, struct page *sb_page, 1288 struct block_device *bdev, 1289 struct cached_dev *dc) 1290 { 1291 const char *err = "cannot allocate memory"; 1292 struct cache_set *c; 1293 1294 bdevname(bdev, dc->backing_dev_name); 1295 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1296 dc->bdev = bdev; 1297 dc->bdev->bd_holder = dc; 1298 1299 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1300 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1301 get_page(sb_page); 1302 1303 1304 if (cached_dev_init(dc, sb->block_size << 9)) 1305 goto err; 1306 1307 err = "error creating kobject"; 1308 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1309 "bcache")) 1310 goto err; 1311 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1312 goto err; 1313 1314 pr_info("registered backing device %s", dc->backing_dev_name); 1315 1316 list_add(&dc->list, &uncached_devices); 1317 /* attach to a matched cache set if it exists */ 1318 list_for_each_entry(c, &bch_cache_sets, list) 1319 bch_cached_dev_attach(dc, c, NULL); 1320 1321 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1322 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1323 bch_cached_dev_run(dc); 1324 1325 return 0; 1326 err: 1327 pr_notice("error %s: %s", dc->backing_dev_name, err); 1328 bcache_device_stop(&dc->disk); 1329 return -EIO; 1330 } 1331 1332 /* Flash only volumes */ 1333 1334 /* When d->kobj released */ 1335 void bch_flash_dev_release(struct kobject *kobj) 1336 { 1337 struct bcache_device *d = container_of(kobj, struct bcache_device, 1338 kobj); 1339 kfree(d); 1340 } 1341 1342 static void flash_dev_free(struct closure *cl) 1343 { 1344 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1345 1346 mutex_lock(&bch_register_lock); 1347 atomic_long_sub(bcache_dev_sectors_dirty(d), 1348 &d->c->flash_dev_dirty_sectors); 1349 bcache_device_free(d); 1350 mutex_unlock(&bch_register_lock); 1351 kobject_put(&d->kobj); 1352 } 1353 1354 static void flash_dev_flush(struct closure *cl) 1355 { 1356 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1357 1358 mutex_lock(&bch_register_lock); 1359 bcache_device_unlink(d); 1360 mutex_unlock(&bch_register_lock); 1361 kobject_del(&d->kobj); 1362 continue_at(cl, flash_dev_free, system_wq); 1363 } 1364 1365 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1366 { 1367 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1368 GFP_KERNEL); 1369 if (!d) 1370 return -ENOMEM; 1371 1372 closure_init(&d->cl, NULL); 1373 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1374 1375 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1376 1377 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1378 goto err; 1379 1380 bcache_device_attach(d, c, u - c->uuids); 1381 bch_sectors_dirty_init(d); 1382 bch_flash_dev_request_init(d); 1383 add_disk(d->disk); 1384 1385 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1386 goto err; 1387 1388 bcache_device_link(d, c, "volume"); 1389 1390 return 0; 1391 err: 1392 kobject_put(&d->kobj); 1393 return -ENOMEM; 1394 } 1395 1396 static int flash_devs_run(struct cache_set *c) 1397 { 1398 int ret = 0; 1399 struct uuid_entry *u; 1400 1401 for (u = c->uuids; 1402 u < c->uuids + c->nr_uuids && !ret; 1403 u++) 1404 if (UUID_FLASH_ONLY(u)) 1405 ret = flash_dev_run(c, u); 1406 1407 return ret; 1408 } 1409 1410 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1411 { 1412 struct uuid_entry *u; 1413 1414 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1415 return -EINTR; 1416 1417 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1418 return -EPERM; 1419 1420 u = uuid_find_empty(c); 1421 if (!u) { 1422 pr_err("Can't create volume, no room for UUID"); 1423 return -EINVAL; 1424 } 1425 1426 get_random_bytes(u->uuid, 16); 1427 memset(u->label, 0, 32); 1428 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); 1429 1430 SET_UUID_FLASH_ONLY(u, 1); 1431 u->sectors = size >> 9; 1432 1433 bch_uuid_write(c); 1434 1435 return flash_dev_run(c, u); 1436 } 1437 1438 bool bch_cached_dev_error(struct cached_dev *dc) 1439 { 1440 struct cache_set *c; 1441 1442 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1443 return false; 1444 1445 dc->io_disable = true; 1446 /* make others know io_disable is true earlier */ 1447 smp_mb(); 1448 1449 pr_err("stop %s: too many IO errors on backing device %s\n", 1450 dc->disk.disk->disk_name, dc->backing_dev_name); 1451 1452 /* 1453 * If the cached device is still attached to a cache set, 1454 * even dc->io_disable is true and no more I/O requests 1455 * accepted, cache device internal I/O (writeback scan or 1456 * garbage collection) may still prevent bcache device from 1457 * being stopped. So here CACHE_SET_IO_DISABLE should be 1458 * set to c->flags too, to make the internal I/O to cache 1459 * device rejected and stopped immediately. 1460 * If c is NULL, that means the bcache device is not attached 1461 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. 1462 */ 1463 c = dc->disk.c; 1464 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1465 pr_info("CACHE_SET_IO_DISABLE already set"); 1466 1467 bcache_device_stop(&dc->disk); 1468 return true; 1469 } 1470 1471 /* Cache set */ 1472 1473 __printf(2, 3) 1474 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1475 { 1476 va_list args; 1477 1478 if (c->on_error != ON_ERROR_PANIC && 1479 test_bit(CACHE_SET_STOPPING, &c->flags)) 1480 return false; 1481 1482 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1483 pr_info("CACHE_SET_IO_DISABLE already set"); 1484 1485 /* 1486 * XXX: we can be called from atomic context 1487 * acquire_console_sem(); 1488 */ 1489 1490 pr_err("bcache: error on %pU: ", c->sb.set_uuid); 1491 1492 va_start(args, fmt); 1493 vprintk(fmt, args); 1494 va_end(args); 1495 1496 pr_err(", disabling caching\n"); 1497 1498 if (c->on_error == ON_ERROR_PANIC) 1499 panic("panic forced after error\n"); 1500 1501 bch_cache_set_unregister(c); 1502 return true; 1503 } 1504 1505 /* When c->kobj released */ 1506 void bch_cache_set_release(struct kobject *kobj) 1507 { 1508 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1509 1510 kfree(c); 1511 module_put(THIS_MODULE); 1512 } 1513 1514 static void cache_set_free(struct closure *cl) 1515 { 1516 struct cache_set *c = container_of(cl, struct cache_set, cl); 1517 struct cache *ca; 1518 unsigned int i; 1519 1520 debugfs_remove(c->debug); 1521 1522 bch_open_buckets_free(c); 1523 bch_btree_cache_free(c); 1524 bch_journal_free(c); 1525 1526 mutex_lock(&bch_register_lock); 1527 for_each_cache(ca, c, i) 1528 if (ca) { 1529 ca->set = NULL; 1530 c->cache[ca->sb.nr_this_dev] = NULL; 1531 kobject_put(&ca->kobj); 1532 } 1533 1534 bch_bset_sort_state_free(&c->sort); 1535 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1536 1537 if (c->moving_gc_wq) 1538 destroy_workqueue(c->moving_gc_wq); 1539 bioset_exit(&c->bio_split); 1540 mempool_exit(&c->fill_iter); 1541 mempool_exit(&c->bio_meta); 1542 mempool_exit(&c->search); 1543 kfree(c->devices); 1544 1545 list_del(&c->list); 1546 mutex_unlock(&bch_register_lock); 1547 1548 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1549 wake_up(&unregister_wait); 1550 1551 closure_debug_destroy(&c->cl); 1552 kobject_put(&c->kobj); 1553 } 1554 1555 static void cache_set_flush(struct closure *cl) 1556 { 1557 struct cache_set *c = container_of(cl, struct cache_set, caching); 1558 struct cache *ca; 1559 struct btree *b; 1560 unsigned int i; 1561 1562 bch_cache_accounting_destroy(&c->accounting); 1563 1564 kobject_put(&c->internal); 1565 kobject_del(&c->kobj); 1566 1567 if (c->gc_thread) 1568 kthread_stop(c->gc_thread); 1569 1570 if (!IS_ERR_OR_NULL(c->root)) 1571 list_add(&c->root->list, &c->btree_cache); 1572 1573 /* Should skip this if we're unregistering because of an error */ 1574 list_for_each_entry(b, &c->btree_cache, list) { 1575 mutex_lock(&b->write_lock); 1576 if (btree_node_dirty(b)) 1577 __bch_btree_node_write(b, NULL); 1578 mutex_unlock(&b->write_lock); 1579 } 1580 1581 for_each_cache(ca, c, i) 1582 if (ca->alloc_thread) 1583 kthread_stop(ca->alloc_thread); 1584 1585 if (c->journal.cur) { 1586 cancel_delayed_work_sync(&c->journal.work); 1587 /* flush last journal entry if needed */ 1588 c->journal.work.work.func(&c->journal.work.work); 1589 } 1590 1591 closure_return(cl); 1592 } 1593 1594 /* 1595 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1596 * cache set is unregistering due to too many I/O errors. In this condition, 1597 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1598 * value and whether the broken cache has dirty data: 1599 * 1600 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1601 * BCH_CACHED_STOP_AUTO 0 NO 1602 * BCH_CACHED_STOP_AUTO 1 YES 1603 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1604 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1605 * 1606 * The expected behavior is, if stop_when_cache_set_failed is configured to 1607 * "auto" via sysfs interface, the bcache device will not be stopped if the 1608 * backing device is clean on the broken cache device. 1609 */ 1610 static void conditional_stop_bcache_device(struct cache_set *c, 1611 struct bcache_device *d, 1612 struct cached_dev *dc) 1613 { 1614 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1615 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1616 d->disk->disk_name, c->sb.set_uuid); 1617 bcache_device_stop(d); 1618 } else if (atomic_read(&dc->has_dirty)) { 1619 /* 1620 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1621 * and dc->has_dirty == 1 1622 */ 1623 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1624 d->disk->disk_name); 1625 /* 1626 * There might be a small time gap that cache set is 1627 * released but bcache device is not. Inside this time 1628 * gap, regular I/O requests will directly go into 1629 * backing device as no cache set attached to. This 1630 * behavior may also introduce potential inconsistence 1631 * data in writeback mode while cache is dirty. 1632 * Therefore before calling bcache_device_stop() due 1633 * to a broken cache device, dc->io_disable should be 1634 * explicitly set to true. 1635 */ 1636 dc->io_disable = true; 1637 /* make others know io_disable is true earlier */ 1638 smp_mb(); 1639 bcache_device_stop(d); 1640 } else { 1641 /* 1642 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1643 * and dc->has_dirty == 0 1644 */ 1645 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1646 d->disk->disk_name); 1647 } 1648 } 1649 1650 static void __cache_set_unregister(struct closure *cl) 1651 { 1652 struct cache_set *c = container_of(cl, struct cache_set, caching); 1653 struct cached_dev *dc; 1654 struct bcache_device *d; 1655 size_t i; 1656 1657 mutex_lock(&bch_register_lock); 1658 1659 for (i = 0; i < c->devices_max_used; i++) { 1660 d = c->devices[i]; 1661 if (!d) 1662 continue; 1663 1664 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1665 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1666 dc = container_of(d, struct cached_dev, disk); 1667 bch_cached_dev_detach(dc); 1668 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1669 conditional_stop_bcache_device(c, d, dc); 1670 } else { 1671 bcache_device_stop(d); 1672 } 1673 } 1674 1675 mutex_unlock(&bch_register_lock); 1676 1677 continue_at(cl, cache_set_flush, system_wq); 1678 } 1679 1680 void bch_cache_set_stop(struct cache_set *c) 1681 { 1682 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1683 /* closure_fn set to __cache_set_unregister() */ 1684 closure_queue(&c->caching); 1685 } 1686 1687 void bch_cache_set_unregister(struct cache_set *c) 1688 { 1689 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1690 bch_cache_set_stop(c); 1691 } 1692 1693 #define alloc_bucket_pages(gfp, c) \ 1694 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1695 1696 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1697 { 1698 int iter_size; 1699 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1700 1701 if (!c) 1702 return NULL; 1703 1704 __module_get(THIS_MODULE); 1705 closure_init(&c->cl, NULL); 1706 set_closure_fn(&c->cl, cache_set_free, system_wq); 1707 1708 closure_init(&c->caching, &c->cl); 1709 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1710 1711 /* Maybe create continue_at_noreturn() and use it here? */ 1712 closure_set_stopped(&c->cl); 1713 closure_put(&c->cl); 1714 1715 kobject_init(&c->kobj, &bch_cache_set_ktype); 1716 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1717 1718 bch_cache_accounting_init(&c->accounting, &c->cl); 1719 1720 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1721 c->sb.block_size = sb->block_size; 1722 c->sb.bucket_size = sb->bucket_size; 1723 c->sb.nr_in_set = sb->nr_in_set; 1724 c->sb.last_mount = sb->last_mount; 1725 c->bucket_bits = ilog2(sb->bucket_size); 1726 c->block_bits = ilog2(sb->block_size); 1727 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1728 c->devices_max_used = 0; 1729 atomic_set(&c->attached_dev_nr, 0); 1730 c->btree_pages = bucket_pages(c); 1731 if (c->btree_pages > BTREE_MAX_PAGES) 1732 c->btree_pages = max_t(int, c->btree_pages / 4, 1733 BTREE_MAX_PAGES); 1734 1735 sema_init(&c->sb_write_mutex, 1); 1736 mutex_init(&c->bucket_lock); 1737 init_waitqueue_head(&c->btree_cache_wait); 1738 init_waitqueue_head(&c->bucket_wait); 1739 init_waitqueue_head(&c->gc_wait); 1740 sema_init(&c->uuid_write_mutex, 1); 1741 1742 spin_lock_init(&c->btree_gc_time.lock); 1743 spin_lock_init(&c->btree_split_time.lock); 1744 spin_lock_init(&c->btree_read_time.lock); 1745 1746 bch_moving_init_cache_set(c); 1747 1748 INIT_LIST_HEAD(&c->list); 1749 INIT_LIST_HEAD(&c->cached_devs); 1750 INIT_LIST_HEAD(&c->btree_cache); 1751 INIT_LIST_HEAD(&c->btree_cache_freeable); 1752 INIT_LIST_HEAD(&c->btree_cache_freed); 1753 INIT_LIST_HEAD(&c->data_buckets); 1754 1755 iter_size = (sb->bucket_size / sb->block_size + 1) * 1756 sizeof(struct btree_iter_set); 1757 1758 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1759 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1760 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1761 sizeof(struct bbio) + sizeof(struct bio_vec) * 1762 bucket_pages(c)) || 1763 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1764 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1765 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1766 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1767 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1768 WQ_MEM_RECLAIM, 0)) || 1769 bch_journal_alloc(c) || 1770 bch_btree_cache_alloc(c) || 1771 bch_open_buckets_alloc(c) || 1772 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1773 goto err; 1774 1775 c->congested_read_threshold_us = 2000; 1776 c->congested_write_threshold_us = 20000; 1777 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1778 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1779 1780 return c; 1781 err: 1782 bch_cache_set_unregister(c); 1783 return NULL; 1784 } 1785 1786 static int run_cache_set(struct cache_set *c) 1787 { 1788 const char *err = "cannot allocate memory"; 1789 struct cached_dev *dc, *t; 1790 struct cache *ca; 1791 struct closure cl; 1792 unsigned int i; 1793 LIST_HEAD(journal); 1794 struct journal_replay *l; 1795 1796 closure_init_stack(&cl); 1797 1798 for_each_cache(ca, c, i) 1799 c->nbuckets += ca->sb.nbuckets; 1800 set_gc_sectors(c); 1801 1802 if (CACHE_SYNC(&c->sb)) { 1803 struct bkey *k; 1804 struct jset *j; 1805 1806 err = "cannot allocate memory for journal"; 1807 if (bch_journal_read(c, &journal)) 1808 goto err; 1809 1810 pr_debug("btree_journal_read() done"); 1811 1812 err = "no journal entries found"; 1813 if (list_empty(&journal)) 1814 goto err; 1815 1816 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1817 1818 err = "IO error reading priorities"; 1819 for_each_cache(ca, c, i) 1820 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1821 1822 /* 1823 * If prio_read() fails it'll call cache_set_error and we'll 1824 * tear everything down right away, but if we perhaps checked 1825 * sooner we could avoid journal replay. 1826 */ 1827 1828 k = &j->btree_root; 1829 1830 err = "bad btree root"; 1831 if (__bch_btree_ptr_invalid(c, k)) 1832 goto err; 1833 1834 err = "error reading btree root"; 1835 c->root = bch_btree_node_get(c, NULL, k, 1836 j->btree_level, 1837 true, NULL); 1838 if (IS_ERR_OR_NULL(c->root)) 1839 goto err; 1840 1841 list_del_init(&c->root->list); 1842 rw_unlock(true, c->root); 1843 1844 err = uuid_read(c, j, &cl); 1845 if (err) 1846 goto err; 1847 1848 err = "error in recovery"; 1849 if (bch_btree_check(c)) 1850 goto err; 1851 1852 bch_journal_mark(c, &journal); 1853 bch_initial_gc_finish(c); 1854 pr_debug("btree_check() done"); 1855 1856 /* 1857 * bcache_journal_next() can't happen sooner, or 1858 * btree_gc_finish() will give spurious errors about last_gc > 1859 * gc_gen - this is a hack but oh well. 1860 */ 1861 bch_journal_next(&c->journal); 1862 1863 err = "error starting allocator thread"; 1864 for_each_cache(ca, c, i) 1865 if (bch_cache_allocator_start(ca)) 1866 goto err; 1867 1868 /* 1869 * First place it's safe to allocate: btree_check() and 1870 * btree_gc_finish() have to run before we have buckets to 1871 * allocate, and bch_bucket_alloc_set() might cause a journal 1872 * entry to be written so bcache_journal_next() has to be called 1873 * first. 1874 * 1875 * If the uuids were in the old format we have to rewrite them 1876 * before the next journal entry is written: 1877 */ 1878 if (j->version < BCACHE_JSET_VERSION_UUID) 1879 __uuid_write(c); 1880 1881 err = "bcache: replay journal failed"; 1882 if (bch_journal_replay(c, &journal)) 1883 goto err; 1884 } else { 1885 pr_notice("invalidating existing data"); 1886 1887 for_each_cache(ca, c, i) { 1888 unsigned int j; 1889 1890 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1891 2, SB_JOURNAL_BUCKETS); 1892 1893 for (j = 0; j < ca->sb.keys; j++) 1894 ca->sb.d[j] = ca->sb.first_bucket + j; 1895 } 1896 1897 bch_initial_gc_finish(c); 1898 1899 err = "error starting allocator thread"; 1900 for_each_cache(ca, c, i) 1901 if (bch_cache_allocator_start(ca)) 1902 goto err; 1903 1904 mutex_lock(&c->bucket_lock); 1905 for_each_cache(ca, c, i) 1906 bch_prio_write(ca); 1907 mutex_unlock(&c->bucket_lock); 1908 1909 err = "cannot allocate new UUID bucket"; 1910 if (__uuid_write(c)) 1911 goto err; 1912 1913 err = "cannot allocate new btree root"; 1914 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1915 if (IS_ERR_OR_NULL(c->root)) 1916 goto err; 1917 1918 mutex_lock(&c->root->write_lock); 1919 bkey_copy_key(&c->root->key, &MAX_KEY); 1920 bch_btree_node_write(c->root, &cl); 1921 mutex_unlock(&c->root->write_lock); 1922 1923 bch_btree_set_root(c->root); 1924 rw_unlock(true, c->root); 1925 1926 /* 1927 * We don't want to write the first journal entry until 1928 * everything is set up - fortunately journal entries won't be 1929 * written until the SET_CACHE_SYNC() here: 1930 */ 1931 SET_CACHE_SYNC(&c->sb, true); 1932 1933 bch_journal_next(&c->journal); 1934 bch_journal_meta(c, &cl); 1935 } 1936 1937 err = "error starting gc thread"; 1938 if (bch_gc_thread_start(c)) 1939 goto err; 1940 1941 closure_sync(&cl); 1942 c->sb.last_mount = (u32)ktime_get_real_seconds(); 1943 bcache_write_super(c); 1944 1945 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1946 bch_cached_dev_attach(dc, c, NULL); 1947 1948 flash_devs_run(c); 1949 1950 set_bit(CACHE_SET_RUNNING, &c->flags); 1951 return 0; 1952 err: 1953 while (!list_empty(&journal)) { 1954 l = list_first_entry(&journal, struct journal_replay, list); 1955 list_del(&l->list); 1956 kfree(l); 1957 } 1958 1959 closure_sync(&cl); 1960 /* XXX: test this, it's broken */ 1961 bch_cache_set_error(c, "%s", err); 1962 1963 return -EIO; 1964 } 1965 1966 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1967 { 1968 return ca->sb.block_size == c->sb.block_size && 1969 ca->sb.bucket_size == c->sb.bucket_size && 1970 ca->sb.nr_in_set == c->sb.nr_in_set; 1971 } 1972 1973 static const char *register_cache_set(struct cache *ca) 1974 { 1975 char buf[12]; 1976 const char *err = "cannot allocate memory"; 1977 struct cache_set *c; 1978 1979 list_for_each_entry(c, &bch_cache_sets, list) 1980 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1981 if (c->cache[ca->sb.nr_this_dev]) 1982 return "duplicate cache set member"; 1983 1984 if (!can_attach_cache(ca, c)) 1985 return "cache sb does not match set"; 1986 1987 if (!CACHE_SYNC(&ca->sb)) 1988 SET_CACHE_SYNC(&c->sb, false); 1989 1990 goto found; 1991 } 1992 1993 c = bch_cache_set_alloc(&ca->sb); 1994 if (!c) 1995 return err; 1996 1997 err = "error creating kobject"; 1998 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1999 kobject_add(&c->internal, &c->kobj, "internal")) 2000 goto err; 2001 2002 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 2003 goto err; 2004 2005 bch_debug_init_cache_set(c); 2006 2007 list_add(&c->list, &bch_cache_sets); 2008 found: 2009 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 2010 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 2011 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 2012 goto err; 2013 2014 if (ca->sb.seq > c->sb.seq) { 2015 c->sb.version = ca->sb.version; 2016 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 2017 c->sb.flags = ca->sb.flags; 2018 c->sb.seq = ca->sb.seq; 2019 pr_debug("set version = %llu", c->sb.version); 2020 } 2021 2022 kobject_get(&ca->kobj); 2023 ca->set = c; 2024 ca->set->cache[ca->sb.nr_this_dev] = ca; 2025 c->cache_by_alloc[c->caches_loaded++] = ca; 2026 2027 if (c->caches_loaded == c->sb.nr_in_set) { 2028 err = "failed to run cache set"; 2029 if (run_cache_set(c) < 0) 2030 goto err; 2031 } 2032 2033 return NULL; 2034 err: 2035 bch_cache_set_unregister(c); 2036 return err; 2037 } 2038 2039 /* Cache device */ 2040 2041 /* When ca->kobj released */ 2042 void bch_cache_release(struct kobject *kobj) 2043 { 2044 struct cache *ca = container_of(kobj, struct cache, kobj); 2045 unsigned int i; 2046 2047 if (ca->set) { 2048 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2049 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2050 } 2051 2052 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2053 kfree(ca->prio_buckets); 2054 vfree(ca->buckets); 2055 2056 free_heap(&ca->heap); 2057 free_fifo(&ca->free_inc); 2058 2059 for (i = 0; i < RESERVE_NR; i++) 2060 free_fifo(&ca->free[i]); 2061 2062 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2063 put_page(bio_first_page_all(&ca->sb_bio)); 2064 2065 if (!IS_ERR_OR_NULL(ca->bdev)) 2066 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2067 2068 kfree(ca); 2069 module_put(THIS_MODULE); 2070 } 2071 2072 static int cache_alloc(struct cache *ca) 2073 { 2074 size_t free; 2075 size_t btree_buckets; 2076 struct bucket *b; 2077 int ret = -ENOMEM; 2078 const char *err = NULL; 2079 2080 __module_get(THIS_MODULE); 2081 kobject_init(&ca->kobj, &bch_cache_ktype); 2082 2083 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2084 2085 /* 2086 * when ca->sb.njournal_buckets is not zero, journal exists, 2087 * and in bch_journal_replay(), tree node may split, 2088 * so bucket of RESERVE_BTREE type is needed, 2089 * the worst situation is all journal buckets are valid journal, 2090 * and all the keys need to replay, 2091 * so the number of RESERVE_BTREE type buckets should be as much 2092 * as journal buckets 2093 */ 2094 btree_buckets = ca->sb.njournal_buckets ?: 8; 2095 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2096 if (!free) { 2097 ret = -EPERM; 2098 err = "ca->sb.nbuckets is too small"; 2099 goto err_free; 2100 } 2101 2102 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, 2103 GFP_KERNEL)) { 2104 err = "ca->free[RESERVE_BTREE] alloc failed"; 2105 goto err_btree_alloc; 2106 } 2107 2108 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), 2109 GFP_KERNEL)) { 2110 err = "ca->free[RESERVE_PRIO] alloc failed"; 2111 goto err_prio_alloc; 2112 } 2113 2114 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) { 2115 err = "ca->free[RESERVE_MOVINGGC] alloc failed"; 2116 goto err_movinggc_alloc; 2117 } 2118 2119 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) { 2120 err = "ca->free[RESERVE_NONE] alloc failed"; 2121 goto err_none_alloc; 2122 } 2123 2124 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) { 2125 err = "ca->free_inc alloc failed"; 2126 goto err_free_inc_alloc; 2127 } 2128 2129 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) { 2130 err = "ca->heap alloc failed"; 2131 goto err_heap_alloc; 2132 } 2133 2134 ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2135 ca->sb.nbuckets)); 2136 if (!ca->buckets) { 2137 err = "ca->buckets alloc failed"; 2138 goto err_buckets_alloc; 2139 } 2140 2141 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2142 prio_buckets(ca), 2), 2143 GFP_KERNEL); 2144 if (!ca->prio_buckets) { 2145 err = "ca->prio_buckets alloc failed"; 2146 goto err_prio_buckets_alloc; 2147 } 2148 2149 ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca); 2150 if (!ca->disk_buckets) { 2151 err = "ca->disk_buckets alloc failed"; 2152 goto err_disk_buckets_alloc; 2153 } 2154 2155 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2156 2157 for_each_bucket(b, ca) 2158 atomic_set(&b->pin, 0); 2159 return 0; 2160 2161 err_disk_buckets_alloc: 2162 kfree(ca->prio_buckets); 2163 err_prio_buckets_alloc: 2164 vfree(ca->buckets); 2165 err_buckets_alloc: 2166 free_heap(&ca->heap); 2167 err_heap_alloc: 2168 free_fifo(&ca->free_inc); 2169 err_free_inc_alloc: 2170 free_fifo(&ca->free[RESERVE_NONE]); 2171 err_none_alloc: 2172 free_fifo(&ca->free[RESERVE_MOVINGGC]); 2173 err_movinggc_alloc: 2174 free_fifo(&ca->free[RESERVE_PRIO]); 2175 err_prio_alloc: 2176 free_fifo(&ca->free[RESERVE_BTREE]); 2177 err_btree_alloc: 2178 err_free: 2179 module_put(THIS_MODULE); 2180 if (err) 2181 pr_notice("error %s: %s", ca->cache_dev_name, err); 2182 return ret; 2183 } 2184 2185 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2186 struct block_device *bdev, struct cache *ca) 2187 { 2188 const char *err = NULL; /* must be set for any error case */ 2189 int ret = 0; 2190 2191 bdevname(bdev, ca->cache_dev_name); 2192 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2193 ca->bdev = bdev; 2194 ca->bdev->bd_holder = ca; 2195 2196 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2197 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2198 get_page(sb_page); 2199 2200 if (blk_queue_discard(bdev_get_queue(bdev))) 2201 ca->discard = CACHE_DISCARD(&ca->sb); 2202 2203 ret = cache_alloc(ca); 2204 if (ret != 0) { 2205 /* 2206 * If we failed here, it means ca->kobj is not initialized yet, 2207 * kobject_put() won't be called and there is no chance to 2208 * call blkdev_put() to bdev in bch_cache_release(). So we 2209 * explicitly call blkdev_put() here. 2210 */ 2211 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2212 if (ret == -ENOMEM) 2213 err = "cache_alloc(): -ENOMEM"; 2214 else if (ret == -EPERM) 2215 err = "cache_alloc(): cache device is too small"; 2216 else 2217 err = "cache_alloc(): unknown error"; 2218 goto err; 2219 } 2220 2221 if (kobject_add(&ca->kobj, 2222 &part_to_dev(bdev->bd_part)->kobj, 2223 "bcache")) { 2224 err = "error calling kobject_add"; 2225 ret = -ENOMEM; 2226 goto out; 2227 } 2228 2229 mutex_lock(&bch_register_lock); 2230 err = register_cache_set(ca); 2231 mutex_unlock(&bch_register_lock); 2232 2233 if (err) { 2234 ret = -ENODEV; 2235 goto out; 2236 } 2237 2238 pr_info("registered cache device %s", ca->cache_dev_name); 2239 2240 out: 2241 kobject_put(&ca->kobj); 2242 2243 err: 2244 if (err) 2245 pr_notice("error %s: %s", ca->cache_dev_name, err); 2246 2247 return ret; 2248 } 2249 2250 /* Global interfaces/init */ 2251 2252 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2253 const char *buffer, size_t size); 2254 2255 kobj_attribute_write(register, register_bcache); 2256 kobj_attribute_write(register_quiet, register_bcache); 2257 2258 static bool bch_is_open_backing(struct block_device *bdev) 2259 { 2260 struct cache_set *c, *tc; 2261 struct cached_dev *dc, *t; 2262 2263 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2264 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2265 if (dc->bdev == bdev) 2266 return true; 2267 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2268 if (dc->bdev == bdev) 2269 return true; 2270 return false; 2271 } 2272 2273 static bool bch_is_open_cache(struct block_device *bdev) 2274 { 2275 struct cache_set *c, *tc; 2276 struct cache *ca; 2277 unsigned int i; 2278 2279 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2280 for_each_cache(ca, c, i) 2281 if (ca->bdev == bdev) 2282 return true; 2283 return false; 2284 } 2285 2286 static bool bch_is_open(struct block_device *bdev) 2287 { 2288 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2289 } 2290 2291 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2292 const char *buffer, size_t size) 2293 { 2294 ssize_t ret = -EINVAL; 2295 const char *err = "cannot allocate memory"; 2296 char *path = NULL; 2297 struct cache_sb *sb = NULL; 2298 struct block_device *bdev = NULL; 2299 struct page *sb_page = NULL; 2300 2301 if (!try_module_get(THIS_MODULE)) 2302 return -EBUSY; 2303 2304 path = kstrndup(buffer, size, GFP_KERNEL); 2305 if (!path) 2306 goto err; 2307 2308 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); 2309 if (!sb) 2310 goto err; 2311 2312 err = "failed to open device"; 2313 bdev = blkdev_get_by_path(strim(path), 2314 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2315 sb); 2316 if (IS_ERR(bdev)) { 2317 if (bdev == ERR_PTR(-EBUSY)) { 2318 bdev = lookup_bdev(strim(path)); 2319 mutex_lock(&bch_register_lock); 2320 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2321 err = "device already registered"; 2322 else 2323 err = "device busy"; 2324 mutex_unlock(&bch_register_lock); 2325 if (!IS_ERR(bdev)) 2326 bdput(bdev); 2327 if (attr == &ksysfs_register_quiet) 2328 goto quiet_out; 2329 } 2330 goto err; 2331 } 2332 2333 err = "failed to set blocksize"; 2334 if (set_blocksize(bdev, 4096)) 2335 goto err_close; 2336 2337 err = read_super(sb, bdev, &sb_page); 2338 if (err) 2339 goto err_close; 2340 2341 err = "failed to register device"; 2342 if (SB_IS_BDEV(sb)) { 2343 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2344 2345 if (!dc) 2346 goto err_close; 2347 2348 mutex_lock(&bch_register_lock); 2349 ret = register_bdev(sb, sb_page, bdev, dc); 2350 mutex_unlock(&bch_register_lock); 2351 /* blkdev_put() will be called in cached_dev_free() */ 2352 if (ret < 0) 2353 goto err; 2354 } else { 2355 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2356 2357 if (!ca) 2358 goto err_close; 2359 2360 /* blkdev_put() will be called in bch_cache_release() */ 2361 if (register_cache(sb, sb_page, bdev, ca) != 0) 2362 goto err; 2363 } 2364 quiet_out: 2365 ret = size; 2366 out: 2367 if (sb_page) 2368 put_page(sb_page); 2369 kfree(sb); 2370 kfree(path); 2371 module_put(THIS_MODULE); 2372 return ret; 2373 2374 err_close: 2375 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2376 err: 2377 pr_info("error %s: %s", path, err); 2378 goto out; 2379 } 2380 2381 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2382 { 2383 if (code == SYS_DOWN || 2384 code == SYS_HALT || 2385 code == SYS_POWER_OFF) { 2386 DEFINE_WAIT(wait); 2387 unsigned long start = jiffies; 2388 bool stopped = false; 2389 2390 struct cache_set *c, *tc; 2391 struct cached_dev *dc, *tdc; 2392 2393 mutex_lock(&bch_register_lock); 2394 2395 if (list_empty(&bch_cache_sets) && 2396 list_empty(&uncached_devices)) 2397 goto out; 2398 2399 pr_info("Stopping all devices:"); 2400 2401 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2402 bch_cache_set_stop(c); 2403 2404 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2405 bcache_device_stop(&dc->disk); 2406 2407 mutex_unlock(&bch_register_lock); 2408 2409 /* 2410 * Give an early chance for other kthreads and 2411 * kworkers to stop themselves 2412 */ 2413 schedule(); 2414 2415 /* What's a condition variable? */ 2416 while (1) { 2417 long timeout = start + 10 * HZ - jiffies; 2418 2419 mutex_lock(&bch_register_lock); 2420 stopped = list_empty(&bch_cache_sets) && 2421 list_empty(&uncached_devices); 2422 2423 if (timeout < 0 || stopped) 2424 break; 2425 2426 prepare_to_wait(&unregister_wait, &wait, 2427 TASK_UNINTERRUPTIBLE); 2428 2429 mutex_unlock(&bch_register_lock); 2430 schedule_timeout(timeout); 2431 } 2432 2433 finish_wait(&unregister_wait, &wait); 2434 2435 if (stopped) 2436 pr_info("All devices stopped"); 2437 else 2438 pr_notice("Timeout waiting for devices to be closed"); 2439 out: 2440 mutex_unlock(&bch_register_lock); 2441 } 2442 2443 return NOTIFY_DONE; 2444 } 2445 2446 static struct notifier_block reboot = { 2447 .notifier_call = bcache_reboot, 2448 .priority = INT_MAX, /* before any real devices */ 2449 }; 2450 2451 static void bcache_exit(void) 2452 { 2453 bch_debug_exit(); 2454 bch_request_exit(); 2455 if (bcache_kobj) 2456 kobject_put(bcache_kobj); 2457 if (bcache_wq) 2458 destroy_workqueue(bcache_wq); 2459 if (bch_journal_wq) 2460 destroy_workqueue(bch_journal_wq); 2461 2462 if (bcache_major) 2463 unregister_blkdev(bcache_major, "bcache"); 2464 unregister_reboot_notifier(&reboot); 2465 mutex_destroy(&bch_register_lock); 2466 } 2467 2468 /* Check and fixup module parameters */ 2469 static void check_module_parameters(void) 2470 { 2471 if (bch_cutoff_writeback_sync == 0) 2472 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC; 2473 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) { 2474 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u", 2475 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX); 2476 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX; 2477 } 2478 2479 if (bch_cutoff_writeback == 0) 2480 bch_cutoff_writeback = CUTOFF_WRITEBACK; 2481 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) { 2482 pr_warn("set bch_cutoff_writeback (%u) to max value %u", 2483 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX); 2484 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX; 2485 } 2486 2487 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) { 2488 pr_warn("set bch_cutoff_writeback (%u) to %u", 2489 bch_cutoff_writeback, bch_cutoff_writeback_sync); 2490 bch_cutoff_writeback = bch_cutoff_writeback_sync; 2491 } 2492 } 2493 2494 static int __init bcache_init(void) 2495 { 2496 static const struct attribute *files[] = { 2497 &ksysfs_register.attr, 2498 &ksysfs_register_quiet.attr, 2499 NULL 2500 }; 2501 2502 check_module_parameters(); 2503 2504 mutex_init(&bch_register_lock); 2505 init_waitqueue_head(&unregister_wait); 2506 register_reboot_notifier(&reboot); 2507 2508 bcache_major = register_blkdev(0, "bcache"); 2509 if (bcache_major < 0) { 2510 unregister_reboot_notifier(&reboot); 2511 mutex_destroy(&bch_register_lock); 2512 return bcache_major; 2513 } 2514 2515 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); 2516 if (!bcache_wq) 2517 goto err; 2518 2519 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); 2520 if (!bch_journal_wq) 2521 goto err; 2522 2523 bcache_kobj = kobject_create_and_add("bcache", fs_kobj); 2524 if (!bcache_kobj) 2525 goto err; 2526 2527 if (bch_request_init() || 2528 sysfs_create_files(bcache_kobj, files)) 2529 goto err; 2530 2531 bch_debug_init(); 2532 closure_debug_init(); 2533 2534 return 0; 2535 err: 2536 bcache_exit(); 2537 return -ENOMEM; 2538 } 2539 2540 /* 2541 * Module hooks 2542 */ 2543 module_exit(bcache_exit); 2544 module_init(bcache_init); 2545 2546 module_param(bch_cutoff_writeback, uint, 0); 2547 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback"); 2548 2549 module_param(bch_cutoff_writeback_sync, uint, 0); 2550 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback"); 2551 2552 MODULE_DESCRIPTION("Bcache: a Linux block layer cache"); 2553 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>"); 2554 MODULE_LICENSE("GPL"); 2555