1 /* 2 * bcache setup/teardown code, and some metadata io - read a superblock and 3 * figure out what to do with it. 4 * 5 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> 6 * Copyright 2012 Google, Inc. 7 */ 8 9 #include "bcache.h" 10 #include "btree.h" 11 #include "debug.h" 12 #include "extents.h" 13 #include "request.h" 14 #include "writeback.h" 15 16 #include <linux/blkdev.h> 17 #include <linux/buffer_head.h> 18 #include <linux/debugfs.h> 19 #include <linux/genhd.h> 20 #include <linux/idr.h> 21 #include <linux/kthread.h> 22 #include <linux/module.h> 23 #include <linux/random.h> 24 #include <linux/reboot.h> 25 #include <linux/sysfs.h> 26 27 MODULE_LICENSE("GPL"); 28 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>"); 29 30 static const char bcache_magic[] = { 31 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca, 32 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 33 }; 34 35 static const char invalid_uuid[] = { 36 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78, 37 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99 38 }; 39 40 /* Default is -1; we skip past it for struct cached_dev's cache mode */ 41 const char * const bch_cache_modes[] = { 42 "default", 43 "writethrough", 44 "writeback", 45 "writearound", 46 "none", 47 NULL 48 }; 49 50 /* Default is -1; we skip past it for stop_when_cache_set_failed */ 51 const char * const bch_stop_on_failure_modes[] = { 52 "default", 53 "auto", 54 "always", 55 NULL 56 }; 57 58 static struct kobject *bcache_kobj; 59 struct mutex bch_register_lock; 60 LIST_HEAD(bch_cache_sets); 61 static LIST_HEAD(uncached_devices); 62 63 static int bcache_major; 64 static DEFINE_IDA(bcache_device_idx); 65 static wait_queue_head_t unregister_wait; 66 struct workqueue_struct *bcache_wq; 67 68 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 69 /* limitation of partitions number on single bcache device */ 70 #define BCACHE_MINORS 128 71 /* limitation of bcache devices number on single system */ 72 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 73 74 /* Superblock */ 75 76 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 77 struct page **res) 78 { 79 const char *err; 80 struct cache_sb *s; 81 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 82 unsigned i; 83 84 if (!bh) 85 return "IO error"; 86 87 s = (struct cache_sb *) bh->b_data; 88 89 sb->offset = le64_to_cpu(s->offset); 90 sb->version = le64_to_cpu(s->version); 91 92 memcpy(sb->magic, s->magic, 16); 93 memcpy(sb->uuid, s->uuid, 16); 94 memcpy(sb->set_uuid, s->set_uuid, 16); 95 memcpy(sb->label, s->label, SB_LABEL_SIZE); 96 97 sb->flags = le64_to_cpu(s->flags); 98 sb->seq = le64_to_cpu(s->seq); 99 sb->last_mount = le32_to_cpu(s->last_mount); 100 sb->first_bucket = le16_to_cpu(s->first_bucket); 101 sb->keys = le16_to_cpu(s->keys); 102 103 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 104 sb->d[i] = le64_to_cpu(s->d[i]); 105 106 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 107 sb->version, sb->flags, sb->seq, sb->keys); 108 109 err = "Not a bcache superblock"; 110 if (sb->offset != SB_SECTOR) 111 goto err; 112 113 if (memcmp(sb->magic, bcache_magic, 16)) 114 goto err; 115 116 err = "Too many journal buckets"; 117 if (sb->keys > SB_JOURNAL_BUCKETS) 118 goto err; 119 120 err = "Bad checksum"; 121 if (s->csum != csum_set(s)) 122 goto err; 123 124 err = "Bad UUID"; 125 if (bch_is_zero(sb->uuid, 16)) 126 goto err; 127 128 sb->block_size = le16_to_cpu(s->block_size); 129 130 err = "Superblock block size smaller than device block size"; 131 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 132 goto err; 133 134 switch (sb->version) { 135 case BCACHE_SB_VERSION_BDEV: 136 sb->data_offset = BDEV_DATA_START_DEFAULT; 137 break; 138 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 139 sb->data_offset = le64_to_cpu(s->data_offset); 140 141 err = "Bad data offset"; 142 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 143 goto err; 144 145 break; 146 case BCACHE_SB_VERSION_CDEV: 147 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 148 sb->nbuckets = le64_to_cpu(s->nbuckets); 149 sb->bucket_size = le16_to_cpu(s->bucket_size); 150 151 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 152 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 153 154 err = "Too many buckets"; 155 if (sb->nbuckets > LONG_MAX) 156 goto err; 157 158 err = "Not enough buckets"; 159 if (sb->nbuckets < 1 << 7) 160 goto err; 161 162 err = "Bad block/bucket size"; 163 if (!is_power_of_2(sb->block_size) || 164 sb->block_size > PAGE_SECTORS || 165 !is_power_of_2(sb->bucket_size) || 166 sb->bucket_size < PAGE_SECTORS) 167 goto err; 168 169 err = "Invalid superblock: device too small"; 170 if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets) 171 goto err; 172 173 err = "Bad UUID"; 174 if (bch_is_zero(sb->set_uuid, 16)) 175 goto err; 176 177 err = "Bad cache device number in set"; 178 if (!sb->nr_in_set || 179 sb->nr_in_set <= sb->nr_this_dev || 180 sb->nr_in_set > MAX_CACHES_PER_SET) 181 goto err; 182 183 err = "Journal buckets not sequential"; 184 for (i = 0; i < sb->keys; i++) 185 if (sb->d[i] != sb->first_bucket + i) 186 goto err; 187 188 err = "Too many journal buckets"; 189 if (sb->first_bucket + sb->keys > sb->nbuckets) 190 goto err; 191 192 err = "Invalid superblock: first bucket comes before end of super"; 193 if (sb->first_bucket * sb->bucket_size < 16) 194 goto err; 195 196 break; 197 default: 198 err = "Unsupported superblock version"; 199 goto err; 200 } 201 202 sb->last_mount = get_seconds(); 203 err = NULL; 204 205 get_page(bh->b_page); 206 *res = bh->b_page; 207 err: 208 put_bh(bh); 209 return err; 210 } 211 212 static void write_bdev_super_endio(struct bio *bio) 213 { 214 struct cached_dev *dc = bio->bi_private; 215 /* XXX: error checking */ 216 217 closure_put(&dc->sb_write); 218 } 219 220 static void __write_super(struct cache_sb *sb, struct bio *bio) 221 { 222 struct cache_sb *out = page_address(bio_first_page_all(bio)); 223 unsigned i; 224 225 bio->bi_iter.bi_sector = SB_SECTOR; 226 bio->bi_iter.bi_size = SB_SIZE; 227 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 228 bch_bio_map(bio, NULL); 229 230 out->offset = cpu_to_le64(sb->offset); 231 out->version = cpu_to_le64(sb->version); 232 233 memcpy(out->uuid, sb->uuid, 16); 234 memcpy(out->set_uuid, sb->set_uuid, 16); 235 memcpy(out->label, sb->label, SB_LABEL_SIZE); 236 237 out->flags = cpu_to_le64(sb->flags); 238 out->seq = cpu_to_le64(sb->seq); 239 240 out->last_mount = cpu_to_le32(sb->last_mount); 241 out->first_bucket = cpu_to_le16(sb->first_bucket); 242 out->keys = cpu_to_le16(sb->keys); 243 244 for (i = 0; i < sb->keys; i++) 245 out->d[i] = cpu_to_le64(sb->d[i]); 246 247 out->csum = csum_set(out); 248 249 pr_debug("ver %llu, flags %llu, seq %llu", 250 sb->version, sb->flags, sb->seq); 251 252 submit_bio(bio); 253 } 254 255 static void bch_write_bdev_super_unlock(struct closure *cl) 256 { 257 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 258 259 up(&dc->sb_write_mutex); 260 } 261 262 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 263 { 264 struct closure *cl = &dc->sb_write; 265 struct bio *bio = &dc->sb_bio; 266 267 down(&dc->sb_write_mutex); 268 closure_init(cl, parent); 269 270 bio_reset(bio); 271 bio_set_dev(bio, dc->bdev); 272 bio->bi_end_io = write_bdev_super_endio; 273 bio->bi_private = dc; 274 275 closure_get(cl); 276 /* I/O request sent to backing device */ 277 __write_super(&dc->sb, bio); 278 279 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 280 } 281 282 static void write_super_endio(struct bio *bio) 283 { 284 struct cache *ca = bio->bi_private; 285 286 /* is_read = 0 */ 287 bch_count_io_errors(ca, bio->bi_status, 0, 288 "writing superblock"); 289 closure_put(&ca->set->sb_write); 290 } 291 292 static void bcache_write_super_unlock(struct closure *cl) 293 { 294 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 295 296 up(&c->sb_write_mutex); 297 } 298 299 void bcache_write_super(struct cache_set *c) 300 { 301 struct closure *cl = &c->sb_write; 302 struct cache *ca; 303 unsigned i; 304 305 down(&c->sb_write_mutex); 306 closure_init(cl, &c->cl); 307 308 c->sb.seq++; 309 310 for_each_cache(ca, c, i) { 311 struct bio *bio = &ca->sb_bio; 312 313 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 314 ca->sb.seq = c->sb.seq; 315 ca->sb.last_mount = c->sb.last_mount; 316 317 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 318 319 bio_reset(bio); 320 bio_set_dev(bio, ca->bdev); 321 bio->bi_end_io = write_super_endio; 322 bio->bi_private = ca; 323 324 closure_get(cl); 325 __write_super(&ca->sb, bio); 326 } 327 328 closure_return_with_destructor(cl, bcache_write_super_unlock); 329 } 330 331 /* UUID io */ 332 333 static void uuid_endio(struct bio *bio) 334 { 335 struct closure *cl = bio->bi_private; 336 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 337 338 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 339 bch_bbio_free(bio, c); 340 closure_put(cl); 341 } 342 343 static void uuid_io_unlock(struct closure *cl) 344 { 345 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 346 347 up(&c->uuid_write_mutex); 348 } 349 350 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 351 struct bkey *k, struct closure *parent) 352 { 353 struct closure *cl = &c->uuid_write; 354 struct uuid_entry *u; 355 unsigned i; 356 char buf[80]; 357 358 BUG_ON(!parent); 359 down(&c->uuid_write_mutex); 360 closure_init(cl, parent); 361 362 for (i = 0; i < KEY_PTRS(k); i++) { 363 struct bio *bio = bch_bbio_alloc(c); 364 365 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 366 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 367 368 bio->bi_end_io = uuid_endio; 369 bio->bi_private = cl; 370 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 371 bch_bio_map(bio, c->uuids); 372 373 bch_submit_bbio(bio, c, k, i); 374 375 if (op != REQ_OP_WRITE) 376 break; 377 } 378 379 bch_extent_to_text(buf, sizeof(buf), k); 380 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 381 382 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 383 if (!bch_is_zero(u->uuid, 16)) 384 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 385 u - c->uuids, u->uuid, u->label, 386 u->first_reg, u->last_reg, u->invalidated); 387 388 closure_return_with_destructor(cl, uuid_io_unlock); 389 } 390 391 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 392 { 393 struct bkey *k = &j->uuid_bucket; 394 395 if (__bch_btree_ptr_invalid(c, k)) 396 return "bad uuid pointer"; 397 398 bkey_copy(&c->uuid_bucket, k); 399 uuid_io(c, REQ_OP_READ, 0, k, cl); 400 401 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 402 struct uuid_entry_v0 *u0 = (void *) c->uuids; 403 struct uuid_entry *u1 = (void *) c->uuids; 404 int i; 405 406 closure_sync(cl); 407 408 /* 409 * Since the new uuid entry is bigger than the old, we have to 410 * convert starting at the highest memory address and work down 411 * in order to do it in place 412 */ 413 414 for (i = c->nr_uuids - 1; 415 i >= 0; 416 --i) { 417 memcpy(u1[i].uuid, u0[i].uuid, 16); 418 memcpy(u1[i].label, u0[i].label, 32); 419 420 u1[i].first_reg = u0[i].first_reg; 421 u1[i].last_reg = u0[i].last_reg; 422 u1[i].invalidated = u0[i].invalidated; 423 424 u1[i].flags = 0; 425 u1[i].sectors = 0; 426 } 427 } 428 429 return NULL; 430 } 431 432 static int __uuid_write(struct cache_set *c) 433 { 434 BKEY_PADDED(key) k; 435 struct closure cl; 436 closure_init_stack(&cl); 437 438 lockdep_assert_held(&bch_register_lock); 439 440 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 441 return 1; 442 443 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 444 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 445 closure_sync(&cl); 446 447 bkey_copy(&c->uuid_bucket, &k.key); 448 bkey_put(c, &k.key); 449 return 0; 450 } 451 452 int bch_uuid_write(struct cache_set *c) 453 { 454 int ret = __uuid_write(c); 455 456 if (!ret) 457 bch_journal_meta(c, NULL); 458 459 return ret; 460 } 461 462 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 463 { 464 struct uuid_entry *u; 465 466 for (u = c->uuids; 467 u < c->uuids + c->nr_uuids; u++) 468 if (!memcmp(u->uuid, uuid, 16)) 469 return u; 470 471 return NULL; 472 } 473 474 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 475 { 476 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 477 return uuid_find(c, zero_uuid); 478 } 479 480 /* 481 * Bucket priorities/gens: 482 * 483 * For each bucket, we store on disk its 484 * 8 bit gen 485 * 16 bit priority 486 * 487 * See alloc.c for an explanation of the gen. The priority is used to implement 488 * lru (and in the future other) cache replacement policies; for most purposes 489 * it's just an opaque integer. 490 * 491 * The gens and the priorities don't have a whole lot to do with each other, and 492 * it's actually the gens that must be written out at specific times - it's no 493 * big deal if the priorities don't get written, if we lose them we just reuse 494 * buckets in suboptimal order. 495 * 496 * On disk they're stored in a packed array, and in as many buckets are required 497 * to fit them all. The buckets we use to store them form a list; the journal 498 * header points to the first bucket, the first bucket points to the second 499 * bucket, et cetera. 500 * 501 * This code is used by the allocation code; periodically (whenever it runs out 502 * of buckets to allocate from) the allocation code will invalidate some 503 * buckets, but it can't use those buckets until their new gens are safely on 504 * disk. 505 */ 506 507 static void prio_endio(struct bio *bio) 508 { 509 struct cache *ca = bio->bi_private; 510 511 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 512 bch_bbio_free(bio, ca->set); 513 closure_put(&ca->prio); 514 } 515 516 static void prio_io(struct cache *ca, uint64_t bucket, int op, 517 unsigned long op_flags) 518 { 519 struct closure *cl = &ca->prio; 520 struct bio *bio = bch_bbio_alloc(ca->set); 521 522 closure_init_stack(cl); 523 524 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 525 bio_set_dev(bio, ca->bdev); 526 bio->bi_iter.bi_size = bucket_bytes(ca); 527 528 bio->bi_end_io = prio_endio; 529 bio->bi_private = ca; 530 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 531 bch_bio_map(bio, ca->disk_buckets); 532 533 closure_bio_submit(ca->set, bio, &ca->prio); 534 closure_sync(cl); 535 } 536 537 void bch_prio_write(struct cache *ca) 538 { 539 int i; 540 struct bucket *b; 541 struct closure cl; 542 543 closure_init_stack(&cl); 544 545 lockdep_assert_held(&ca->set->bucket_lock); 546 547 ca->disk_buckets->seq++; 548 549 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 550 &ca->meta_sectors_written); 551 552 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 553 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 554 555 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 556 long bucket; 557 struct prio_set *p = ca->disk_buckets; 558 struct bucket_disk *d = p->data; 559 struct bucket_disk *end = d + prios_per_bucket(ca); 560 561 for (b = ca->buckets + i * prios_per_bucket(ca); 562 b < ca->buckets + ca->sb.nbuckets && d < end; 563 b++, d++) { 564 d->prio = cpu_to_le16(b->prio); 565 d->gen = b->gen; 566 } 567 568 p->next_bucket = ca->prio_buckets[i + 1]; 569 p->magic = pset_magic(&ca->sb); 570 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 571 572 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 573 BUG_ON(bucket == -1); 574 575 mutex_unlock(&ca->set->bucket_lock); 576 prio_io(ca, bucket, REQ_OP_WRITE, 0); 577 mutex_lock(&ca->set->bucket_lock); 578 579 ca->prio_buckets[i] = bucket; 580 atomic_dec_bug(&ca->buckets[bucket].pin); 581 } 582 583 mutex_unlock(&ca->set->bucket_lock); 584 585 bch_journal_meta(ca->set, &cl); 586 closure_sync(&cl); 587 588 mutex_lock(&ca->set->bucket_lock); 589 590 /* 591 * Don't want the old priorities to get garbage collected until after we 592 * finish writing the new ones, and they're journalled 593 */ 594 for (i = 0; i < prio_buckets(ca); i++) { 595 if (ca->prio_last_buckets[i]) 596 __bch_bucket_free(ca, 597 &ca->buckets[ca->prio_last_buckets[i]]); 598 599 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 600 } 601 } 602 603 static void prio_read(struct cache *ca, uint64_t bucket) 604 { 605 struct prio_set *p = ca->disk_buckets; 606 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 607 struct bucket *b; 608 unsigned bucket_nr = 0; 609 610 for (b = ca->buckets; 611 b < ca->buckets + ca->sb.nbuckets; 612 b++, d++) { 613 if (d == end) { 614 ca->prio_buckets[bucket_nr] = bucket; 615 ca->prio_last_buckets[bucket_nr] = bucket; 616 bucket_nr++; 617 618 prio_io(ca, bucket, REQ_OP_READ, 0); 619 620 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 621 pr_warn("bad csum reading priorities"); 622 623 if (p->magic != pset_magic(&ca->sb)) 624 pr_warn("bad magic reading priorities"); 625 626 bucket = p->next_bucket; 627 d = p->data; 628 } 629 630 b->prio = le16_to_cpu(d->prio); 631 b->gen = b->last_gc = d->gen; 632 } 633 } 634 635 /* Bcache device */ 636 637 static int open_dev(struct block_device *b, fmode_t mode) 638 { 639 struct bcache_device *d = b->bd_disk->private_data; 640 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 641 return -ENXIO; 642 643 closure_get(&d->cl); 644 return 0; 645 } 646 647 static void release_dev(struct gendisk *b, fmode_t mode) 648 { 649 struct bcache_device *d = b->private_data; 650 closure_put(&d->cl); 651 } 652 653 static int ioctl_dev(struct block_device *b, fmode_t mode, 654 unsigned int cmd, unsigned long arg) 655 { 656 struct bcache_device *d = b->bd_disk->private_data; 657 struct cached_dev *dc = container_of(d, struct cached_dev, disk); 658 659 if (dc->io_disable) 660 return -EIO; 661 662 return d->ioctl(d, mode, cmd, arg); 663 } 664 665 static const struct block_device_operations bcache_ops = { 666 .open = open_dev, 667 .release = release_dev, 668 .ioctl = ioctl_dev, 669 .owner = THIS_MODULE, 670 }; 671 672 void bcache_device_stop(struct bcache_device *d) 673 { 674 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 675 closure_queue(&d->cl); 676 } 677 678 static void bcache_device_unlink(struct bcache_device *d) 679 { 680 lockdep_assert_held(&bch_register_lock); 681 682 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 683 unsigned i; 684 struct cache *ca; 685 686 sysfs_remove_link(&d->c->kobj, d->name); 687 sysfs_remove_link(&d->kobj, "cache"); 688 689 for_each_cache(ca, d->c, i) 690 bd_unlink_disk_holder(ca->bdev, d->disk); 691 } 692 } 693 694 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 695 const char *name) 696 { 697 unsigned i; 698 struct cache *ca; 699 700 for_each_cache(ca, d->c, i) 701 bd_link_disk_holder(ca->bdev, d->disk); 702 703 snprintf(d->name, BCACHEDEVNAME_SIZE, 704 "%s%u", name, d->id); 705 706 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 707 sysfs_create_link(&c->kobj, &d->kobj, d->name), 708 "Couldn't create device <-> cache set symlinks"); 709 710 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 711 } 712 713 static void bcache_device_detach(struct bcache_device *d) 714 { 715 lockdep_assert_held(&bch_register_lock); 716 717 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 718 struct uuid_entry *u = d->c->uuids + d->id; 719 720 SET_UUID_FLASH_ONLY(u, 0); 721 memcpy(u->uuid, invalid_uuid, 16); 722 u->invalidated = cpu_to_le32(get_seconds()); 723 bch_uuid_write(d->c); 724 } 725 726 bcache_device_unlink(d); 727 728 d->c->devices[d->id] = NULL; 729 closure_put(&d->c->caching); 730 d->c = NULL; 731 } 732 733 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 734 unsigned id) 735 { 736 d->id = id; 737 d->c = c; 738 c->devices[id] = d; 739 740 if (id >= c->devices_max_used) 741 c->devices_max_used = id + 1; 742 743 closure_get(&c->caching); 744 } 745 746 static inline int first_minor_to_idx(int first_minor) 747 { 748 return (first_minor/BCACHE_MINORS); 749 } 750 751 static inline int idx_to_first_minor(int idx) 752 { 753 return (idx * BCACHE_MINORS); 754 } 755 756 static void bcache_device_free(struct bcache_device *d) 757 { 758 lockdep_assert_held(&bch_register_lock); 759 760 pr_info("%s stopped", d->disk->disk_name); 761 762 if (d->c) 763 bcache_device_detach(d); 764 if (d->disk && d->disk->flags & GENHD_FL_UP) 765 del_gendisk(d->disk); 766 if (d->disk && d->disk->queue) 767 blk_cleanup_queue(d->disk->queue); 768 if (d->disk) { 769 ida_simple_remove(&bcache_device_idx, 770 first_minor_to_idx(d->disk->first_minor)); 771 put_disk(d->disk); 772 } 773 774 if (d->bio_split) 775 bioset_free(d->bio_split); 776 kvfree(d->full_dirty_stripes); 777 kvfree(d->stripe_sectors_dirty); 778 779 closure_debug_destroy(&d->cl); 780 } 781 782 static int bcache_device_init(struct bcache_device *d, unsigned block_size, 783 sector_t sectors) 784 { 785 struct request_queue *q; 786 const size_t max_stripes = min_t(size_t, INT_MAX, 787 SIZE_MAX / sizeof(atomic_t)); 788 size_t n; 789 int idx; 790 791 if (!d->stripe_size) 792 d->stripe_size = 1 << 31; 793 794 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 795 796 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 797 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 798 (unsigned)d->nr_stripes); 799 return -ENOMEM; 800 } 801 802 n = d->nr_stripes * sizeof(atomic_t); 803 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 804 if (!d->stripe_sectors_dirty) 805 return -ENOMEM; 806 807 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 808 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 809 if (!d->full_dirty_stripes) 810 return -ENOMEM; 811 812 idx = ida_simple_get(&bcache_device_idx, 0, 813 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 814 if (idx < 0) 815 return idx; 816 817 if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio), 818 BIOSET_NEED_BVECS | 819 BIOSET_NEED_RESCUER)) || 820 !(d->disk = alloc_disk(BCACHE_MINORS))) { 821 ida_simple_remove(&bcache_device_idx, idx); 822 return -ENOMEM; 823 } 824 825 set_capacity(d->disk, sectors); 826 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 827 828 d->disk->major = bcache_major; 829 d->disk->first_minor = idx_to_first_minor(idx); 830 d->disk->fops = &bcache_ops; 831 d->disk->private_data = d; 832 833 q = blk_alloc_queue(GFP_KERNEL); 834 if (!q) 835 return -ENOMEM; 836 837 blk_queue_make_request(q, NULL); 838 d->disk->queue = q; 839 q->queuedata = d; 840 q->backing_dev_info->congested_data = d; 841 q->limits.max_hw_sectors = UINT_MAX; 842 q->limits.max_sectors = UINT_MAX; 843 q->limits.max_segment_size = UINT_MAX; 844 q->limits.max_segments = BIO_MAX_PAGES; 845 blk_queue_max_discard_sectors(q, UINT_MAX); 846 q->limits.discard_granularity = 512; 847 q->limits.io_min = block_size; 848 q->limits.logical_block_size = block_size; 849 q->limits.physical_block_size = block_size; 850 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 851 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 852 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 853 854 blk_queue_write_cache(q, true, true); 855 856 return 0; 857 } 858 859 /* Cached device */ 860 861 static void calc_cached_dev_sectors(struct cache_set *c) 862 { 863 uint64_t sectors = 0; 864 struct cached_dev *dc; 865 866 list_for_each_entry(dc, &c->cached_devs, list) 867 sectors += bdev_sectors(dc->bdev); 868 869 c->cached_dev_sectors = sectors; 870 } 871 872 #define BACKING_DEV_OFFLINE_TIMEOUT 5 873 static int cached_dev_status_update(void *arg) 874 { 875 struct cached_dev *dc = arg; 876 struct request_queue *q; 877 878 /* 879 * If this delayed worker is stopping outside, directly quit here. 880 * dc->io_disable might be set via sysfs interface, so check it 881 * here too. 882 */ 883 while (!kthread_should_stop() && !dc->io_disable) { 884 q = bdev_get_queue(dc->bdev); 885 if (blk_queue_dying(q)) 886 dc->offline_seconds++; 887 else 888 dc->offline_seconds = 0; 889 890 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 891 pr_err("%s: device offline for %d seconds", 892 dc->backing_dev_name, 893 BACKING_DEV_OFFLINE_TIMEOUT); 894 pr_err("%s: disable I/O request due to backing " 895 "device offline", dc->disk.name); 896 dc->io_disable = true; 897 /* let others know earlier that io_disable is true */ 898 smp_mb(); 899 bcache_device_stop(&dc->disk); 900 break; 901 } 902 schedule_timeout_interruptible(HZ); 903 } 904 905 wait_for_kthread_stop(); 906 return 0; 907 } 908 909 910 void bch_cached_dev_run(struct cached_dev *dc) 911 { 912 struct bcache_device *d = &dc->disk; 913 char buf[SB_LABEL_SIZE + 1]; 914 char *env[] = { 915 "DRIVER=bcache", 916 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 917 NULL, 918 NULL, 919 }; 920 921 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 922 buf[SB_LABEL_SIZE] = '\0'; 923 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 924 925 if (atomic_xchg(&dc->running, 1)) { 926 kfree(env[1]); 927 kfree(env[2]); 928 return; 929 } 930 931 if (!d->c && 932 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 933 struct closure cl; 934 closure_init_stack(&cl); 935 936 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 937 bch_write_bdev_super(dc, &cl); 938 closure_sync(&cl); 939 } 940 941 add_disk(d->disk); 942 bd_link_disk_holder(dc->bdev, dc->disk.disk); 943 /* won't show up in the uevent file, use udevadm monitor -e instead 944 * only class / kset properties are persistent */ 945 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 946 kfree(env[1]); 947 kfree(env[2]); 948 949 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 950 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 951 pr_debug("error creating sysfs link"); 952 953 dc->status_update_thread = kthread_run(cached_dev_status_update, 954 dc, "bcache_status_update"); 955 if (IS_ERR(dc->status_update_thread)) { 956 pr_warn("failed to create bcache_status_update kthread, " 957 "continue to run without monitoring backing " 958 "device status"); 959 } 960 } 961 962 /* 963 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 964 * work dc->writeback_rate_update is running. Wait until the routine 965 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 966 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 967 * seconds, give up waiting here and continue to cancel it too. 968 */ 969 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 970 { 971 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 972 973 do { 974 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 975 &dc->disk.flags)) 976 break; 977 time_out--; 978 schedule_timeout_interruptible(1); 979 } while (time_out > 0); 980 981 if (time_out == 0) 982 pr_warn("give up waiting for dc->writeback_write_update to quit"); 983 984 cancel_delayed_work_sync(&dc->writeback_rate_update); 985 } 986 987 static void cached_dev_detach_finish(struct work_struct *w) 988 { 989 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 990 struct closure cl; 991 closure_init_stack(&cl); 992 993 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 994 BUG_ON(refcount_read(&dc->count)); 995 996 mutex_lock(&bch_register_lock); 997 998 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 999 cancel_writeback_rate_update_dwork(dc); 1000 1001 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 1002 kthread_stop(dc->writeback_thread); 1003 dc->writeback_thread = NULL; 1004 } 1005 1006 memset(&dc->sb.set_uuid, 0, 16); 1007 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 1008 1009 bch_write_bdev_super(dc, &cl); 1010 closure_sync(&cl); 1011 1012 bcache_device_detach(&dc->disk); 1013 list_move(&dc->list, &uncached_devices); 1014 1015 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1016 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1017 1018 mutex_unlock(&bch_register_lock); 1019 1020 pr_info("Caching disabled for %s", dc->backing_dev_name); 1021 1022 /* Drop ref we took in cached_dev_detach() */ 1023 closure_put(&dc->disk.cl); 1024 } 1025 1026 void bch_cached_dev_detach(struct cached_dev *dc) 1027 { 1028 lockdep_assert_held(&bch_register_lock); 1029 1030 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1031 return; 1032 1033 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1034 return; 1035 1036 /* 1037 * Block the device from being closed and freed until we're finished 1038 * detaching 1039 */ 1040 closure_get(&dc->disk.cl); 1041 1042 bch_writeback_queue(dc); 1043 1044 cached_dev_put(dc); 1045 } 1046 1047 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1048 uint8_t *set_uuid) 1049 { 1050 uint32_t rtime = cpu_to_le32(get_seconds()); 1051 struct uuid_entry *u; 1052 struct cached_dev *exist_dc, *t; 1053 1054 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1055 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1056 return -ENOENT; 1057 1058 if (dc->disk.c) { 1059 pr_err("Can't attach %s: already attached", 1060 dc->backing_dev_name); 1061 return -EINVAL; 1062 } 1063 1064 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1065 pr_err("Can't attach %s: shutting down", 1066 dc->backing_dev_name); 1067 return -EINVAL; 1068 } 1069 1070 if (dc->sb.block_size < c->sb.block_size) { 1071 /* Will die */ 1072 pr_err("Couldn't attach %s: block size less than set's block size", 1073 dc->backing_dev_name); 1074 return -EINVAL; 1075 } 1076 1077 /* Check whether already attached */ 1078 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1079 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1080 pr_err("Tried to attach %s but duplicate UUID already attached", 1081 dc->backing_dev_name); 1082 1083 return -EINVAL; 1084 } 1085 } 1086 1087 u = uuid_find(c, dc->sb.uuid); 1088 1089 if (u && 1090 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1091 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1092 memcpy(u->uuid, invalid_uuid, 16); 1093 u->invalidated = cpu_to_le32(get_seconds()); 1094 u = NULL; 1095 } 1096 1097 if (!u) { 1098 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1099 pr_err("Couldn't find uuid for %s in set", 1100 dc->backing_dev_name); 1101 return -ENOENT; 1102 } 1103 1104 u = uuid_find_empty(c); 1105 if (!u) { 1106 pr_err("Not caching %s, no room for UUID", 1107 dc->backing_dev_name); 1108 return -EINVAL; 1109 } 1110 } 1111 1112 /* Deadlocks since we're called via sysfs... 1113 sysfs_remove_file(&dc->kobj, &sysfs_attach); 1114 */ 1115 1116 if (bch_is_zero(u->uuid, 16)) { 1117 struct closure cl; 1118 closure_init_stack(&cl); 1119 1120 memcpy(u->uuid, dc->sb.uuid, 16); 1121 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1122 u->first_reg = u->last_reg = rtime; 1123 bch_uuid_write(c); 1124 1125 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1126 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1127 1128 bch_write_bdev_super(dc, &cl); 1129 closure_sync(&cl); 1130 } else { 1131 u->last_reg = rtime; 1132 bch_uuid_write(c); 1133 } 1134 1135 bcache_device_attach(&dc->disk, c, u - c->uuids); 1136 list_move(&dc->list, &c->cached_devs); 1137 calc_cached_dev_sectors(c); 1138 1139 smp_wmb(); 1140 /* 1141 * dc->c must be set before dc->count != 0 - paired with the mb in 1142 * cached_dev_get() 1143 */ 1144 refcount_set(&dc->count, 1); 1145 1146 /* Block writeback thread, but spawn it */ 1147 down_write(&dc->writeback_lock); 1148 if (bch_cached_dev_writeback_start(dc)) { 1149 up_write(&dc->writeback_lock); 1150 return -ENOMEM; 1151 } 1152 1153 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1154 bch_sectors_dirty_init(&dc->disk); 1155 atomic_set(&dc->has_dirty, 1); 1156 bch_writeback_queue(dc); 1157 } 1158 1159 bch_cached_dev_run(dc); 1160 bcache_device_link(&dc->disk, c, "bdev"); 1161 1162 /* Allow the writeback thread to proceed */ 1163 up_write(&dc->writeback_lock); 1164 1165 pr_info("Caching %s as %s on set %pU", 1166 dc->backing_dev_name, 1167 dc->disk.disk->disk_name, 1168 dc->disk.c->sb.set_uuid); 1169 return 0; 1170 } 1171 1172 void bch_cached_dev_release(struct kobject *kobj) 1173 { 1174 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1175 disk.kobj); 1176 kfree(dc); 1177 module_put(THIS_MODULE); 1178 } 1179 1180 static void cached_dev_free(struct closure *cl) 1181 { 1182 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1183 1184 mutex_lock(&bch_register_lock); 1185 1186 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1187 cancel_writeback_rate_update_dwork(dc); 1188 1189 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1190 kthread_stop(dc->writeback_thread); 1191 if (dc->writeback_write_wq) 1192 destroy_workqueue(dc->writeback_write_wq); 1193 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1194 kthread_stop(dc->status_update_thread); 1195 1196 if (atomic_read(&dc->running)) 1197 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1198 bcache_device_free(&dc->disk); 1199 list_del(&dc->list); 1200 1201 mutex_unlock(&bch_register_lock); 1202 1203 if (!IS_ERR_OR_NULL(dc->bdev)) 1204 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1205 1206 wake_up(&unregister_wait); 1207 1208 kobject_put(&dc->disk.kobj); 1209 } 1210 1211 static void cached_dev_flush(struct closure *cl) 1212 { 1213 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1214 struct bcache_device *d = &dc->disk; 1215 1216 mutex_lock(&bch_register_lock); 1217 bcache_device_unlink(d); 1218 mutex_unlock(&bch_register_lock); 1219 1220 bch_cache_accounting_destroy(&dc->accounting); 1221 kobject_del(&d->kobj); 1222 1223 continue_at(cl, cached_dev_free, system_wq); 1224 } 1225 1226 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1227 { 1228 int ret; 1229 struct io *io; 1230 struct request_queue *q = bdev_get_queue(dc->bdev); 1231 1232 __module_get(THIS_MODULE); 1233 INIT_LIST_HEAD(&dc->list); 1234 closure_init(&dc->disk.cl, NULL); 1235 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1236 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1237 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1238 sema_init(&dc->sb_write_mutex, 1); 1239 INIT_LIST_HEAD(&dc->io_lru); 1240 spin_lock_init(&dc->io_lock); 1241 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1242 1243 dc->sequential_cutoff = 4 << 20; 1244 1245 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1246 list_add(&io->lru, &dc->io_lru); 1247 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1248 } 1249 1250 dc->disk.stripe_size = q->limits.io_opt >> 9; 1251 1252 if (dc->disk.stripe_size) 1253 dc->partial_stripes_expensive = 1254 q->limits.raid_partial_stripes_expensive; 1255 1256 ret = bcache_device_init(&dc->disk, block_size, 1257 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1258 if (ret) 1259 return ret; 1260 1261 dc->disk.disk->queue->backing_dev_info->ra_pages = 1262 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1263 q->backing_dev_info->ra_pages); 1264 1265 atomic_set(&dc->io_errors, 0); 1266 dc->io_disable = false; 1267 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1268 /* default to auto */ 1269 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1270 1271 bch_cached_dev_request_init(dc); 1272 bch_cached_dev_writeback_init(dc); 1273 return 0; 1274 } 1275 1276 /* Cached device - bcache superblock */ 1277 1278 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1279 struct block_device *bdev, 1280 struct cached_dev *dc) 1281 { 1282 const char *err = "cannot allocate memory"; 1283 struct cache_set *c; 1284 1285 bdevname(bdev, dc->backing_dev_name); 1286 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1287 dc->bdev = bdev; 1288 dc->bdev->bd_holder = dc; 1289 1290 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1291 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1292 get_page(sb_page); 1293 1294 1295 if (cached_dev_init(dc, sb->block_size << 9)) 1296 goto err; 1297 1298 err = "error creating kobject"; 1299 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1300 "bcache")) 1301 goto err; 1302 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1303 goto err; 1304 1305 pr_info("registered backing device %s", dc->backing_dev_name); 1306 1307 list_add(&dc->list, &uncached_devices); 1308 list_for_each_entry(c, &bch_cache_sets, list) 1309 bch_cached_dev_attach(dc, c, NULL); 1310 1311 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1312 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1313 bch_cached_dev_run(dc); 1314 1315 return; 1316 err: 1317 pr_notice("error %s: %s", dc->backing_dev_name, err); 1318 bcache_device_stop(&dc->disk); 1319 } 1320 1321 /* Flash only volumes */ 1322 1323 void bch_flash_dev_release(struct kobject *kobj) 1324 { 1325 struct bcache_device *d = container_of(kobj, struct bcache_device, 1326 kobj); 1327 kfree(d); 1328 } 1329 1330 static void flash_dev_free(struct closure *cl) 1331 { 1332 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1333 mutex_lock(&bch_register_lock); 1334 bcache_device_free(d); 1335 mutex_unlock(&bch_register_lock); 1336 kobject_put(&d->kobj); 1337 } 1338 1339 static void flash_dev_flush(struct closure *cl) 1340 { 1341 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1342 1343 mutex_lock(&bch_register_lock); 1344 bcache_device_unlink(d); 1345 mutex_unlock(&bch_register_lock); 1346 kobject_del(&d->kobj); 1347 continue_at(cl, flash_dev_free, system_wq); 1348 } 1349 1350 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1351 { 1352 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1353 GFP_KERNEL); 1354 if (!d) 1355 return -ENOMEM; 1356 1357 closure_init(&d->cl, NULL); 1358 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1359 1360 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1361 1362 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1363 goto err; 1364 1365 bcache_device_attach(d, c, u - c->uuids); 1366 bch_sectors_dirty_init(d); 1367 bch_flash_dev_request_init(d); 1368 add_disk(d->disk); 1369 1370 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1371 goto err; 1372 1373 bcache_device_link(d, c, "volume"); 1374 1375 return 0; 1376 err: 1377 kobject_put(&d->kobj); 1378 return -ENOMEM; 1379 } 1380 1381 static int flash_devs_run(struct cache_set *c) 1382 { 1383 int ret = 0; 1384 struct uuid_entry *u; 1385 1386 for (u = c->uuids; 1387 u < c->uuids + c->nr_uuids && !ret; 1388 u++) 1389 if (UUID_FLASH_ONLY(u)) 1390 ret = flash_dev_run(c, u); 1391 1392 return ret; 1393 } 1394 1395 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1396 { 1397 struct uuid_entry *u; 1398 1399 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1400 return -EINTR; 1401 1402 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1403 return -EPERM; 1404 1405 u = uuid_find_empty(c); 1406 if (!u) { 1407 pr_err("Can't create volume, no room for UUID"); 1408 return -EINVAL; 1409 } 1410 1411 get_random_bytes(u->uuid, 16); 1412 memset(u->label, 0, 32); 1413 u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); 1414 1415 SET_UUID_FLASH_ONLY(u, 1); 1416 u->sectors = size >> 9; 1417 1418 bch_uuid_write(c); 1419 1420 return flash_dev_run(c, u); 1421 } 1422 1423 bool bch_cached_dev_error(struct cached_dev *dc) 1424 { 1425 struct cache_set *c; 1426 1427 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1428 return false; 1429 1430 dc->io_disable = true; 1431 /* make others know io_disable is true earlier */ 1432 smp_mb(); 1433 1434 pr_err("stop %s: too many IO errors on backing device %s\n", 1435 dc->disk.disk->disk_name, dc->backing_dev_name); 1436 1437 /* 1438 * If the cached device is still attached to a cache set, 1439 * even dc->io_disable is true and no more I/O requests 1440 * accepted, cache device internal I/O (writeback scan or 1441 * garbage collection) may still prevent bcache device from 1442 * being stopped. So here CACHE_SET_IO_DISABLE should be 1443 * set to c->flags too, to make the internal I/O to cache 1444 * device rejected and stopped immediately. 1445 * If c is NULL, that means the bcache device is not attached 1446 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. 1447 */ 1448 c = dc->disk.c; 1449 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1450 pr_info("CACHE_SET_IO_DISABLE already set"); 1451 1452 bcache_device_stop(&dc->disk); 1453 return true; 1454 } 1455 1456 /* Cache set */ 1457 1458 __printf(2, 3) 1459 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1460 { 1461 va_list args; 1462 1463 if (c->on_error != ON_ERROR_PANIC && 1464 test_bit(CACHE_SET_STOPPING, &c->flags)) 1465 return false; 1466 1467 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1468 pr_info("CACHE_SET_IO_DISABLE already set"); 1469 1470 /* XXX: we can be called from atomic context 1471 acquire_console_sem(); 1472 */ 1473 1474 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1475 1476 va_start(args, fmt); 1477 vprintk(fmt, args); 1478 va_end(args); 1479 1480 printk(", disabling caching\n"); 1481 1482 if (c->on_error == ON_ERROR_PANIC) 1483 panic("panic forced after error\n"); 1484 1485 bch_cache_set_unregister(c); 1486 return true; 1487 } 1488 1489 void bch_cache_set_release(struct kobject *kobj) 1490 { 1491 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1492 kfree(c); 1493 module_put(THIS_MODULE); 1494 } 1495 1496 static void cache_set_free(struct closure *cl) 1497 { 1498 struct cache_set *c = container_of(cl, struct cache_set, cl); 1499 struct cache *ca; 1500 unsigned i; 1501 1502 if (!IS_ERR_OR_NULL(c->debug)) 1503 debugfs_remove(c->debug); 1504 1505 bch_open_buckets_free(c); 1506 bch_btree_cache_free(c); 1507 bch_journal_free(c); 1508 1509 for_each_cache(ca, c, i) 1510 if (ca) { 1511 ca->set = NULL; 1512 c->cache[ca->sb.nr_this_dev] = NULL; 1513 kobject_put(&ca->kobj); 1514 } 1515 1516 bch_bset_sort_state_free(&c->sort); 1517 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1518 1519 if (c->moving_gc_wq) 1520 destroy_workqueue(c->moving_gc_wq); 1521 if (c->bio_split) 1522 bioset_free(c->bio_split); 1523 if (c->fill_iter) 1524 mempool_destroy(c->fill_iter); 1525 if (c->bio_meta) 1526 mempool_destroy(c->bio_meta); 1527 if (c->search) 1528 mempool_destroy(c->search); 1529 kfree(c->devices); 1530 1531 mutex_lock(&bch_register_lock); 1532 list_del(&c->list); 1533 mutex_unlock(&bch_register_lock); 1534 1535 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1536 wake_up(&unregister_wait); 1537 1538 closure_debug_destroy(&c->cl); 1539 kobject_put(&c->kobj); 1540 } 1541 1542 static void cache_set_flush(struct closure *cl) 1543 { 1544 struct cache_set *c = container_of(cl, struct cache_set, caching); 1545 struct cache *ca; 1546 struct btree *b; 1547 unsigned i; 1548 1549 bch_cache_accounting_destroy(&c->accounting); 1550 1551 kobject_put(&c->internal); 1552 kobject_del(&c->kobj); 1553 1554 if (c->gc_thread) 1555 kthread_stop(c->gc_thread); 1556 1557 if (!IS_ERR_OR_NULL(c->root)) 1558 list_add(&c->root->list, &c->btree_cache); 1559 1560 /* Should skip this if we're unregistering because of an error */ 1561 list_for_each_entry(b, &c->btree_cache, list) { 1562 mutex_lock(&b->write_lock); 1563 if (btree_node_dirty(b)) 1564 __bch_btree_node_write(b, NULL); 1565 mutex_unlock(&b->write_lock); 1566 } 1567 1568 for_each_cache(ca, c, i) 1569 if (ca->alloc_thread) 1570 kthread_stop(ca->alloc_thread); 1571 1572 if (c->journal.cur) { 1573 cancel_delayed_work_sync(&c->journal.work); 1574 /* flush last journal entry if needed */ 1575 c->journal.work.work.func(&c->journal.work.work); 1576 } 1577 1578 closure_return(cl); 1579 } 1580 1581 /* 1582 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1583 * cache set is unregistering due to too many I/O errors. In this condition, 1584 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1585 * value and whether the broken cache has dirty data: 1586 * 1587 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1588 * BCH_CACHED_STOP_AUTO 0 NO 1589 * BCH_CACHED_STOP_AUTO 1 YES 1590 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1591 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1592 * 1593 * The expected behavior is, if stop_when_cache_set_failed is configured to 1594 * "auto" via sysfs interface, the bcache device will not be stopped if the 1595 * backing device is clean on the broken cache device. 1596 */ 1597 static void conditional_stop_bcache_device(struct cache_set *c, 1598 struct bcache_device *d, 1599 struct cached_dev *dc) 1600 { 1601 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1602 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1603 d->disk->disk_name, c->sb.set_uuid); 1604 bcache_device_stop(d); 1605 } else if (atomic_read(&dc->has_dirty)) { 1606 /* 1607 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1608 * and dc->has_dirty == 1 1609 */ 1610 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1611 d->disk->disk_name); 1612 /* 1613 * There might be a small time gap that cache set is 1614 * released but bcache device is not. Inside this time 1615 * gap, regular I/O requests will directly go into 1616 * backing device as no cache set attached to. This 1617 * behavior may also introduce potential inconsistence 1618 * data in writeback mode while cache is dirty. 1619 * Therefore before calling bcache_device_stop() due 1620 * to a broken cache device, dc->io_disable should be 1621 * explicitly set to true. 1622 */ 1623 dc->io_disable = true; 1624 /* make others know io_disable is true earlier */ 1625 smp_mb(); 1626 bcache_device_stop(d); 1627 } else { 1628 /* 1629 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1630 * and dc->has_dirty == 0 1631 */ 1632 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1633 d->disk->disk_name); 1634 } 1635 } 1636 1637 static void __cache_set_unregister(struct closure *cl) 1638 { 1639 struct cache_set *c = container_of(cl, struct cache_set, caching); 1640 struct cached_dev *dc; 1641 struct bcache_device *d; 1642 size_t i; 1643 1644 mutex_lock(&bch_register_lock); 1645 1646 for (i = 0; i < c->devices_max_used; i++) { 1647 d = c->devices[i]; 1648 if (!d) 1649 continue; 1650 1651 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1652 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1653 dc = container_of(d, struct cached_dev, disk); 1654 bch_cached_dev_detach(dc); 1655 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1656 conditional_stop_bcache_device(c, d, dc); 1657 } else { 1658 bcache_device_stop(d); 1659 } 1660 } 1661 1662 mutex_unlock(&bch_register_lock); 1663 1664 continue_at(cl, cache_set_flush, system_wq); 1665 } 1666 1667 void bch_cache_set_stop(struct cache_set *c) 1668 { 1669 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1670 closure_queue(&c->caching); 1671 } 1672 1673 void bch_cache_set_unregister(struct cache_set *c) 1674 { 1675 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1676 bch_cache_set_stop(c); 1677 } 1678 1679 #define alloc_bucket_pages(gfp, c) \ 1680 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1681 1682 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1683 { 1684 int iter_size; 1685 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1686 if (!c) 1687 return NULL; 1688 1689 __module_get(THIS_MODULE); 1690 closure_init(&c->cl, NULL); 1691 set_closure_fn(&c->cl, cache_set_free, system_wq); 1692 1693 closure_init(&c->caching, &c->cl); 1694 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1695 1696 /* Maybe create continue_at_noreturn() and use it here? */ 1697 closure_set_stopped(&c->cl); 1698 closure_put(&c->cl); 1699 1700 kobject_init(&c->kobj, &bch_cache_set_ktype); 1701 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1702 1703 bch_cache_accounting_init(&c->accounting, &c->cl); 1704 1705 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1706 c->sb.block_size = sb->block_size; 1707 c->sb.bucket_size = sb->bucket_size; 1708 c->sb.nr_in_set = sb->nr_in_set; 1709 c->sb.last_mount = sb->last_mount; 1710 c->bucket_bits = ilog2(sb->bucket_size); 1711 c->block_bits = ilog2(sb->block_size); 1712 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1713 c->devices_max_used = 0; 1714 c->btree_pages = bucket_pages(c); 1715 if (c->btree_pages > BTREE_MAX_PAGES) 1716 c->btree_pages = max_t(int, c->btree_pages / 4, 1717 BTREE_MAX_PAGES); 1718 1719 sema_init(&c->sb_write_mutex, 1); 1720 mutex_init(&c->bucket_lock); 1721 init_waitqueue_head(&c->btree_cache_wait); 1722 init_waitqueue_head(&c->bucket_wait); 1723 init_waitqueue_head(&c->gc_wait); 1724 sema_init(&c->uuid_write_mutex, 1); 1725 1726 spin_lock_init(&c->btree_gc_time.lock); 1727 spin_lock_init(&c->btree_split_time.lock); 1728 spin_lock_init(&c->btree_read_time.lock); 1729 1730 bch_moving_init_cache_set(c); 1731 1732 INIT_LIST_HEAD(&c->list); 1733 INIT_LIST_HEAD(&c->cached_devs); 1734 INIT_LIST_HEAD(&c->btree_cache); 1735 INIT_LIST_HEAD(&c->btree_cache_freeable); 1736 INIT_LIST_HEAD(&c->btree_cache_freed); 1737 INIT_LIST_HEAD(&c->data_buckets); 1738 1739 c->search = mempool_create_slab_pool(32, bch_search_cache); 1740 if (!c->search) 1741 goto err; 1742 1743 iter_size = (sb->bucket_size / sb->block_size + 1) * 1744 sizeof(struct btree_iter_set); 1745 1746 if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) || 1747 !(c->bio_meta = mempool_create_kmalloc_pool(2, 1748 sizeof(struct bbio) + sizeof(struct bio_vec) * 1749 bucket_pages(c))) || 1750 !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) || 1751 !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio), 1752 BIOSET_NEED_BVECS | 1753 BIOSET_NEED_RESCUER)) || 1754 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1755 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1756 WQ_MEM_RECLAIM, 0)) || 1757 bch_journal_alloc(c) || 1758 bch_btree_cache_alloc(c) || 1759 bch_open_buckets_alloc(c) || 1760 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1761 goto err; 1762 1763 c->congested_read_threshold_us = 2000; 1764 c->congested_write_threshold_us = 20000; 1765 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1766 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1767 1768 return c; 1769 err: 1770 bch_cache_set_unregister(c); 1771 return NULL; 1772 } 1773 1774 static void run_cache_set(struct cache_set *c) 1775 { 1776 const char *err = "cannot allocate memory"; 1777 struct cached_dev *dc, *t; 1778 struct cache *ca; 1779 struct closure cl; 1780 unsigned i; 1781 1782 closure_init_stack(&cl); 1783 1784 for_each_cache(ca, c, i) 1785 c->nbuckets += ca->sb.nbuckets; 1786 set_gc_sectors(c); 1787 1788 if (CACHE_SYNC(&c->sb)) { 1789 LIST_HEAD(journal); 1790 struct bkey *k; 1791 struct jset *j; 1792 1793 err = "cannot allocate memory for journal"; 1794 if (bch_journal_read(c, &journal)) 1795 goto err; 1796 1797 pr_debug("btree_journal_read() done"); 1798 1799 err = "no journal entries found"; 1800 if (list_empty(&journal)) 1801 goto err; 1802 1803 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1804 1805 err = "IO error reading priorities"; 1806 for_each_cache(ca, c, i) 1807 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1808 1809 /* 1810 * If prio_read() fails it'll call cache_set_error and we'll 1811 * tear everything down right away, but if we perhaps checked 1812 * sooner we could avoid journal replay. 1813 */ 1814 1815 k = &j->btree_root; 1816 1817 err = "bad btree root"; 1818 if (__bch_btree_ptr_invalid(c, k)) 1819 goto err; 1820 1821 err = "error reading btree root"; 1822 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1823 if (IS_ERR_OR_NULL(c->root)) 1824 goto err; 1825 1826 list_del_init(&c->root->list); 1827 rw_unlock(true, c->root); 1828 1829 err = uuid_read(c, j, &cl); 1830 if (err) 1831 goto err; 1832 1833 err = "error in recovery"; 1834 if (bch_btree_check(c)) 1835 goto err; 1836 1837 bch_journal_mark(c, &journal); 1838 bch_initial_gc_finish(c); 1839 pr_debug("btree_check() done"); 1840 1841 /* 1842 * bcache_journal_next() can't happen sooner, or 1843 * btree_gc_finish() will give spurious errors about last_gc > 1844 * gc_gen - this is a hack but oh well. 1845 */ 1846 bch_journal_next(&c->journal); 1847 1848 err = "error starting allocator thread"; 1849 for_each_cache(ca, c, i) 1850 if (bch_cache_allocator_start(ca)) 1851 goto err; 1852 1853 /* 1854 * First place it's safe to allocate: btree_check() and 1855 * btree_gc_finish() have to run before we have buckets to 1856 * allocate, and bch_bucket_alloc_set() might cause a journal 1857 * entry to be written so bcache_journal_next() has to be called 1858 * first. 1859 * 1860 * If the uuids were in the old format we have to rewrite them 1861 * before the next journal entry is written: 1862 */ 1863 if (j->version < BCACHE_JSET_VERSION_UUID) 1864 __uuid_write(c); 1865 1866 bch_journal_replay(c, &journal); 1867 } else { 1868 pr_notice("invalidating existing data"); 1869 1870 for_each_cache(ca, c, i) { 1871 unsigned j; 1872 1873 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1874 2, SB_JOURNAL_BUCKETS); 1875 1876 for (j = 0; j < ca->sb.keys; j++) 1877 ca->sb.d[j] = ca->sb.first_bucket + j; 1878 } 1879 1880 bch_initial_gc_finish(c); 1881 1882 err = "error starting allocator thread"; 1883 for_each_cache(ca, c, i) 1884 if (bch_cache_allocator_start(ca)) 1885 goto err; 1886 1887 mutex_lock(&c->bucket_lock); 1888 for_each_cache(ca, c, i) 1889 bch_prio_write(ca); 1890 mutex_unlock(&c->bucket_lock); 1891 1892 err = "cannot allocate new UUID bucket"; 1893 if (__uuid_write(c)) 1894 goto err; 1895 1896 err = "cannot allocate new btree root"; 1897 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1898 if (IS_ERR_OR_NULL(c->root)) 1899 goto err; 1900 1901 mutex_lock(&c->root->write_lock); 1902 bkey_copy_key(&c->root->key, &MAX_KEY); 1903 bch_btree_node_write(c->root, &cl); 1904 mutex_unlock(&c->root->write_lock); 1905 1906 bch_btree_set_root(c->root); 1907 rw_unlock(true, c->root); 1908 1909 /* 1910 * We don't want to write the first journal entry until 1911 * everything is set up - fortunately journal entries won't be 1912 * written until the SET_CACHE_SYNC() here: 1913 */ 1914 SET_CACHE_SYNC(&c->sb, true); 1915 1916 bch_journal_next(&c->journal); 1917 bch_journal_meta(c, &cl); 1918 } 1919 1920 err = "error starting gc thread"; 1921 if (bch_gc_thread_start(c)) 1922 goto err; 1923 1924 closure_sync(&cl); 1925 c->sb.last_mount = get_seconds(); 1926 bcache_write_super(c); 1927 1928 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1929 bch_cached_dev_attach(dc, c, NULL); 1930 1931 flash_devs_run(c); 1932 1933 set_bit(CACHE_SET_RUNNING, &c->flags); 1934 return; 1935 err: 1936 closure_sync(&cl); 1937 /* XXX: test this, it's broken */ 1938 bch_cache_set_error(c, "%s", err); 1939 } 1940 1941 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1942 { 1943 return ca->sb.block_size == c->sb.block_size && 1944 ca->sb.bucket_size == c->sb.bucket_size && 1945 ca->sb.nr_in_set == c->sb.nr_in_set; 1946 } 1947 1948 static const char *register_cache_set(struct cache *ca) 1949 { 1950 char buf[12]; 1951 const char *err = "cannot allocate memory"; 1952 struct cache_set *c; 1953 1954 list_for_each_entry(c, &bch_cache_sets, list) 1955 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1956 if (c->cache[ca->sb.nr_this_dev]) 1957 return "duplicate cache set member"; 1958 1959 if (!can_attach_cache(ca, c)) 1960 return "cache sb does not match set"; 1961 1962 if (!CACHE_SYNC(&ca->sb)) 1963 SET_CACHE_SYNC(&c->sb, false); 1964 1965 goto found; 1966 } 1967 1968 c = bch_cache_set_alloc(&ca->sb); 1969 if (!c) 1970 return err; 1971 1972 err = "error creating kobject"; 1973 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1974 kobject_add(&c->internal, &c->kobj, "internal")) 1975 goto err; 1976 1977 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1978 goto err; 1979 1980 bch_debug_init_cache_set(c); 1981 1982 list_add(&c->list, &bch_cache_sets); 1983 found: 1984 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1985 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1986 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1987 goto err; 1988 1989 if (ca->sb.seq > c->sb.seq) { 1990 c->sb.version = ca->sb.version; 1991 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1992 c->sb.flags = ca->sb.flags; 1993 c->sb.seq = ca->sb.seq; 1994 pr_debug("set version = %llu", c->sb.version); 1995 } 1996 1997 kobject_get(&ca->kobj); 1998 ca->set = c; 1999 ca->set->cache[ca->sb.nr_this_dev] = ca; 2000 c->cache_by_alloc[c->caches_loaded++] = ca; 2001 2002 if (c->caches_loaded == c->sb.nr_in_set) 2003 run_cache_set(c); 2004 2005 return NULL; 2006 err: 2007 bch_cache_set_unregister(c); 2008 return err; 2009 } 2010 2011 /* Cache device */ 2012 2013 void bch_cache_release(struct kobject *kobj) 2014 { 2015 struct cache *ca = container_of(kobj, struct cache, kobj); 2016 unsigned i; 2017 2018 if (ca->set) { 2019 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2020 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2021 } 2022 2023 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2024 kfree(ca->prio_buckets); 2025 vfree(ca->buckets); 2026 2027 free_heap(&ca->heap); 2028 free_fifo(&ca->free_inc); 2029 2030 for (i = 0; i < RESERVE_NR; i++) 2031 free_fifo(&ca->free[i]); 2032 2033 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2034 put_page(bio_first_page_all(&ca->sb_bio)); 2035 2036 if (!IS_ERR_OR_NULL(ca->bdev)) 2037 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2038 2039 kfree(ca); 2040 module_put(THIS_MODULE); 2041 } 2042 2043 static int cache_alloc(struct cache *ca) 2044 { 2045 size_t free; 2046 size_t btree_buckets; 2047 struct bucket *b; 2048 2049 __module_get(THIS_MODULE); 2050 kobject_init(&ca->kobj, &bch_cache_ktype); 2051 2052 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2053 2054 /* 2055 * when ca->sb.njournal_buckets is not zero, journal exists, 2056 * and in bch_journal_replay(), tree node may split, 2057 * so bucket of RESERVE_BTREE type is needed, 2058 * the worst situation is all journal buckets are valid journal, 2059 * and all the keys need to replay, 2060 * so the number of RESERVE_BTREE type buckets should be as much 2061 * as journal buckets 2062 */ 2063 btree_buckets = ca->sb.njournal_buckets ?: 8; 2064 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2065 2066 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) || 2067 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 2068 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 2069 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 2070 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 2071 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 2072 !(ca->buckets = vzalloc(sizeof(struct bucket) * 2073 ca->sb.nbuckets)) || 2074 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 2075 2, GFP_KERNEL)) || 2076 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 2077 return -ENOMEM; 2078 2079 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2080 2081 for_each_bucket(b, ca) 2082 atomic_set(&b->pin, 0); 2083 2084 return 0; 2085 } 2086 2087 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2088 struct block_device *bdev, struct cache *ca) 2089 { 2090 const char *err = NULL; /* must be set for any error case */ 2091 int ret = 0; 2092 2093 bdevname(bdev, ca->cache_dev_name); 2094 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2095 ca->bdev = bdev; 2096 ca->bdev->bd_holder = ca; 2097 2098 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2099 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2100 get_page(sb_page); 2101 2102 if (blk_queue_discard(bdev_get_queue(bdev))) 2103 ca->discard = CACHE_DISCARD(&ca->sb); 2104 2105 ret = cache_alloc(ca); 2106 if (ret != 0) { 2107 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2108 if (ret == -ENOMEM) 2109 err = "cache_alloc(): -ENOMEM"; 2110 else 2111 err = "cache_alloc(): unknown error"; 2112 goto err; 2113 } 2114 2115 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 2116 err = "error calling kobject_add"; 2117 ret = -ENOMEM; 2118 goto out; 2119 } 2120 2121 mutex_lock(&bch_register_lock); 2122 err = register_cache_set(ca); 2123 mutex_unlock(&bch_register_lock); 2124 2125 if (err) { 2126 ret = -ENODEV; 2127 goto out; 2128 } 2129 2130 pr_info("registered cache device %s", ca->cache_dev_name); 2131 2132 out: 2133 kobject_put(&ca->kobj); 2134 2135 err: 2136 if (err) 2137 pr_notice("error %s: %s", ca->cache_dev_name, err); 2138 2139 return ret; 2140 } 2141 2142 /* Global interfaces/init */ 2143 2144 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 2145 const char *, size_t); 2146 2147 kobj_attribute_write(register, register_bcache); 2148 kobj_attribute_write(register_quiet, register_bcache); 2149 2150 static bool bch_is_open_backing(struct block_device *bdev) { 2151 struct cache_set *c, *tc; 2152 struct cached_dev *dc, *t; 2153 2154 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2155 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2156 if (dc->bdev == bdev) 2157 return true; 2158 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2159 if (dc->bdev == bdev) 2160 return true; 2161 return false; 2162 } 2163 2164 static bool bch_is_open_cache(struct block_device *bdev) { 2165 struct cache_set *c, *tc; 2166 struct cache *ca; 2167 unsigned i; 2168 2169 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2170 for_each_cache(ca, c, i) 2171 if (ca->bdev == bdev) 2172 return true; 2173 return false; 2174 } 2175 2176 static bool bch_is_open(struct block_device *bdev) { 2177 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2178 } 2179 2180 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2181 const char *buffer, size_t size) 2182 { 2183 ssize_t ret = size; 2184 const char *err = "cannot allocate memory"; 2185 char *path = NULL; 2186 struct cache_sb *sb = NULL; 2187 struct block_device *bdev = NULL; 2188 struct page *sb_page = NULL; 2189 2190 if (!try_module_get(THIS_MODULE)) 2191 return -EBUSY; 2192 2193 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || 2194 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) 2195 goto err; 2196 2197 err = "failed to open device"; 2198 bdev = blkdev_get_by_path(strim(path), 2199 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2200 sb); 2201 if (IS_ERR(bdev)) { 2202 if (bdev == ERR_PTR(-EBUSY)) { 2203 bdev = lookup_bdev(strim(path)); 2204 mutex_lock(&bch_register_lock); 2205 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2206 err = "device already registered"; 2207 else 2208 err = "device busy"; 2209 mutex_unlock(&bch_register_lock); 2210 if (!IS_ERR(bdev)) 2211 bdput(bdev); 2212 if (attr == &ksysfs_register_quiet) 2213 goto out; 2214 } 2215 goto err; 2216 } 2217 2218 err = "failed to set blocksize"; 2219 if (set_blocksize(bdev, 4096)) 2220 goto err_close; 2221 2222 err = read_super(sb, bdev, &sb_page); 2223 if (err) 2224 goto err_close; 2225 2226 err = "failed to register device"; 2227 if (SB_IS_BDEV(sb)) { 2228 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2229 if (!dc) 2230 goto err_close; 2231 2232 mutex_lock(&bch_register_lock); 2233 register_bdev(sb, sb_page, bdev, dc); 2234 mutex_unlock(&bch_register_lock); 2235 } else { 2236 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2237 if (!ca) 2238 goto err_close; 2239 2240 if (register_cache(sb, sb_page, bdev, ca) != 0) 2241 goto err; 2242 } 2243 out: 2244 if (sb_page) 2245 put_page(sb_page); 2246 kfree(sb); 2247 kfree(path); 2248 module_put(THIS_MODULE); 2249 return ret; 2250 2251 err_close: 2252 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2253 err: 2254 pr_info("error %s: %s", path, err); 2255 ret = -EINVAL; 2256 goto out; 2257 } 2258 2259 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2260 { 2261 if (code == SYS_DOWN || 2262 code == SYS_HALT || 2263 code == SYS_POWER_OFF) { 2264 DEFINE_WAIT(wait); 2265 unsigned long start = jiffies; 2266 bool stopped = false; 2267 2268 struct cache_set *c, *tc; 2269 struct cached_dev *dc, *tdc; 2270 2271 mutex_lock(&bch_register_lock); 2272 2273 if (list_empty(&bch_cache_sets) && 2274 list_empty(&uncached_devices)) 2275 goto out; 2276 2277 pr_info("Stopping all devices:"); 2278 2279 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2280 bch_cache_set_stop(c); 2281 2282 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2283 bcache_device_stop(&dc->disk); 2284 2285 /* What's a condition variable? */ 2286 while (1) { 2287 long timeout = start + 2 * HZ - jiffies; 2288 2289 stopped = list_empty(&bch_cache_sets) && 2290 list_empty(&uncached_devices); 2291 2292 if (timeout < 0 || stopped) 2293 break; 2294 2295 prepare_to_wait(&unregister_wait, &wait, 2296 TASK_UNINTERRUPTIBLE); 2297 2298 mutex_unlock(&bch_register_lock); 2299 schedule_timeout(timeout); 2300 mutex_lock(&bch_register_lock); 2301 } 2302 2303 finish_wait(&unregister_wait, &wait); 2304 2305 if (stopped) 2306 pr_info("All devices stopped"); 2307 else 2308 pr_notice("Timeout waiting for devices to be closed"); 2309 out: 2310 mutex_unlock(&bch_register_lock); 2311 } 2312 2313 return NOTIFY_DONE; 2314 } 2315 2316 static struct notifier_block reboot = { 2317 .notifier_call = bcache_reboot, 2318 .priority = INT_MAX, /* before any real devices */ 2319 }; 2320 2321 static void bcache_exit(void) 2322 { 2323 bch_debug_exit(); 2324 bch_request_exit(); 2325 if (bcache_kobj) 2326 kobject_put(bcache_kobj); 2327 if (bcache_wq) 2328 destroy_workqueue(bcache_wq); 2329 if (bcache_major) 2330 unregister_blkdev(bcache_major, "bcache"); 2331 unregister_reboot_notifier(&reboot); 2332 mutex_destroy(&bch_register_lock); 2333 } 2334 2335 static int __init bcache_init(void) 2336 { 2337 static const struct attribute *files[] = { 2338 &ksysfs_register.attr, 2339 &ksysfs_register_quiet.attr, 2340 NULL 2341 }; 2342 2343 mutex_init(&bch_register_lock); 2344 init_waitqueue_head(&unregister_wait); 2345 register_reboot_notifier(&reboot); 2346 2347 bcache_major = register_blkdev(0, "bcache"); 2348 if (bcache_major < 0) { 2349 unregister_reboot_notifier(&reboot); 2350 mutex_destroy(&bch_register_lock); 2351 return bcache_major; 2352 } 2353 2354 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) || 2355 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || 2356 bch_request_init() || 2357 bch_debug_init(bcache_kobj) || closure_debug_init() || 2358 sysfs_create_files(bcache_kobj, files)) 2359 goto err; 2360 2361 return 0; 2362 err: 2363 bcache_exit(); 2364 return -ENOMEM; 2365 } 2366 2367 module_exit(bcache_exit); 2368 module_init(bcache_init); 2369