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 static struct kobject *bcache_kobj; 41 struct mutex bch_register_lock; 42 LIST_HEAD(bch_cache_sets); 43 static LIST_HEAD(uncached_devices); 44 45 static int bcache_major; 46 static DEFINE_IDA(bcache_device_idx); 47 static wait_queue_head_t unregister_wait; 48 struct workqueue_struct *bcache_wq; 49 50 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 51 /* limitation of partitions number on single bcache device */ 52 #define BCACHE_MINORS 128 53 /* limitation of bcache devices number on single system */ 54 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 55 56 /* Superblock */ 57 58 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 59 struct page **res) 60 { 61 const char *err; 62 struct cache_sb *s; 63 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 64 unsigned i; 65 66 if (!bh) 67 return "IO error"; 68 69 s = (struct cache_sb *) bh->b_data; 70 71 sb->offset = le64_to_cpu(s->offset); 72 sb->version = le64_to_cpu(s->version); 73 74 memcpy(sb->magic, s->magic, 16); 75 memcpy(sb->uuid, s->uuid, 16); 76 memcpy(sb->set_uuid, s->set_uuid, 16); 77 memcpy(sb->label, s->label, SB_LABEL_SIZE); 78 79 sb->flags = le64_to_cpu(s->flags); 80 sb->seq = le64_to_cpu(s->seq); 81 sb->last_mount = le32_to_cpu(s->last_mount); 82 sb->first_bucket = le16_to_cpu(s->first_bucket); 83 sb->keys = le16_to_cpu(s->keys); 84 85 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 86 sb->d[i] = le64_to_cpu(s->d[i]); 87 88 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 89 sb->version, sb->flags, sb->seq, sb->keys); 90 91 err = "Not a bcache superblock"; 92 if (sb->offset != SB_SECTOR) 93 goto err; 94 95 if (memcmp(sb->magic, bcache_magic, 16)) 96 goto err; 97 98 err = "Too many journal buckets"; 99 if (sb->keys > SB_JOURNAL_BUCKETS) 100 goto err; 101 102 err = "Bad checksum"; 103 if (s->csum != csum_set(s)) 104 goto err; 105 106 err = "Bad UUID"; 107 if (bch_is_zero(sb->uuid, 16)) 108 goto err; 109 110 sb->block_size = le16_to_cpu(s->block_size); 111 112 err = "Superblock block size smaller than device block size"; 113 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 114 goto err; 115 116 switch (sb->version) { 117 case BCACHE_SB_VERSION_BDEV: 118 sb->data_offset = BDEV_DATA_START_DEFAULT; 119 break; 120 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 121 sb->data_offset = le64_to_cpu(s->data_offset); 122 123 err = "Bad data offset"; 124 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 125 goto err; 126 127 break; 128 case BCACHE_SB_VERSION_CDEV: 129 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 130 sb->nbuckets = le64_to_cpu(s->nbuckets); 131 sb->bucket_size = le16_to_cpu(s->bucket_size); 132 133 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 134 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 135 136 err = "Too many buckets"; 137 if (sb->nbuckets > LONG_MAX) 138 goto err; 139 140 err = "Not enough buckets"; 141 if (sb->nbuckets < 1 << 7) 142 goto err; 143 144 err = "Bad block/bucket size"; 145 if (!is_power_of_2(sb->block_size) || 146 sb->block_size > PAGE_SECTORS || 147 !is_power_of_2(sb->bucket_size) || 148 sb->bucket_size < PAGE_SECTORS) 149 goto err; 150 151 err = "Invalid superblock: device too small"; 152 if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets) 153 goto err; 154 155 err = "Bad UUID"; 156 if (bch_is_zero(sb->set_uuid, 16)) 157 goto err; 158 159 err = "Bad cache device number in set"; 160 if (!sb->nr_in_set || 161 sb->nr_in_set <= sb->nr_this_dev || 162 sb->nr_in_set > MAX_CACHES_PER_SET) 163 goto err; 164 165 err = "Journal buckets not sequential"; 166 for (i = 0; i < sb->keys; i++) 167 if (sb->d[i] != sb->first_bucket + i) 168 goto err; 169 170 err = "Too many journal buckets"; 171 if (sb->first_bucket + sb->keys > sb->nbuckets) 172 goto err; 173 174 err = "Invalid superblock: first bucket comes before end of super"; 175 if (sb->first_bucket * sb->bucket_size < 16) 176 goto err; 177 178 break; 179 default: 180 err = "Unsupported superblock version"; 181 goto err; 182 } 183 184 sb->last_mount = get_seconds(); 185 err = NULL; 186 187 get_page(bh->b_page); 188 *res = bh->b_page; 189 err: 190 put_bh(bh); 191 return err; 192 } 193 194 static void write_bdev_super_endio(struct bio *bio) 195 { 196 struct cached_dev *dc = bio->bi_private; 197 /* XXX: error checking */ 198 199 closure_put(&dc->sb_write); 200 } 201 202 static void __write_super(struct cache_sb *sb, struct bio *bio) 203 { 204 struct cache_sb *out = page_address(bio_first_page_all(bio)); 205 unsigned i; 206 207 bio->bi_iter.bi_sector = SB_SECTOR; 208 bio->bi_iter.bi_size = SB_SIZE; 209 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 210 bch_bio_map(bio, NULL); 211 212 out->offset = cpu_to_le64(sb->offset); 213 out->version = cpu_to_le64(sb->version); 214 215 memcpy(out->uuid, sb->uuid, 16); 216 memcpy(out->set_uuid, sb->set_uuid, 16); 217 memcpy(out->label, sb->label, SB_LABEL_SIZE); 218 219 out->flags = cpu_to_le64(sb->flags); 220 out->seq = cpu_to_le64(sb->seq); 221 222 out->last_mount = cpu_to_le32(sb->last_mount); 223 out->first_bucket = cpu_to_le16(sb->first_bucket); 224 out->keys = cpu_to_le16(sb->keys); 225 226 for (i = 0; i < sb->keys; i++) 227 out->d[i] = cpu_to_le64(sb->d[i]); 228 229 out->csum = csum_set(out); 230 231 pr_debug("ver %llu, flags %llu, seq %llu", 232 sb->version, sb->flags, sb->seq); 233 234 submit_bio(bio); 235 } 236 237 static void bch_write_bdev_super_unlock(struct closure *cl) 238 { 239 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 240 241 up(&dc->sb_write_mutex); 242 } 243 244 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 245 { 246 struct closure *cl = &dc->sb_write; 247 struct bio *bio = &dc->sb_bio; 248 249 down(&dc->sb_write_mutex); 250 closure_init(cl, parent); 251 252 bio_reset(bio); 253 bio_set_dev(bio, dc->bdev); 254 bio->bi_end_io = write_bdev_super_endio; 255 bio->bi_private = dc; 256 257 closure_get(cl); 258 /* I/O request sent to backing device */ 259 __write_super(&dc->sb, bio); 260 261 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 262 } 263 264 static void write_super_endio(struct bio *bio) 265 { 266 struct cache *ca = bio->bi_private; 267 268 /* is_read = 0 */ 269 bch_count_io_errors(ca, bio->bi_status, 0, 270 "writing superblock"); 271 closure_put(&ca->set->sb_write); 272 } 273 274 static void bcache_write_super_unlock(struct closure *cl) 275 { 276 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 277 278 up(&c->sb_write_mutex); 279 } 280 281 void bcache_write_super(struct cache_set *c) 282 { 283 struct closure *cl = &c->sb_write; 284 struct cache *ca; 285 unsigned i; 286 287 down(&c->sb_write_mutex); 288 closure_init(cl, &c->cl); 289 290 c->sb.seq++; 291 292 for_each_cache(ca, c, i) { 293 struct bio *bio = &ca->sb_bio; 294 295 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 296 ca->sb.seq = c->sb.seq; 297 ca->sb.last_mount = c->sb.last_mount; 298 299 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 300 301 bio_reset(bio); 302 bio_set_dev(bio, ca->bdev); 303 bio->bi_end_io = write_super_endio; 304 bio->bi_private = ca; 305 306 closure_get(cl); 307 __write_super(&ca->sb, bio); 308 } 309 310 closure_return_with_destructor(cl, bcache_write_super_unlock); 311 } 312 313 /* UUID io */ 314 315 static void uuid_endio(struct bio *bio) 316 { 317 struct closure *cl = bio->bi_private; 318 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 319 320 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 321 bch_bbio_free(bio, c); 322 closure_put(cl); 323 } 324 325 static void uuid_io_unlock(struct closure *cl) 326 { 327 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 328 329 up(&c->uuid_write_mutex); 330 } 331 332 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 333 struct bkey *k, struct closure *parent) 334 { 335 struct closure *cl = &c->uuid_write; 336 struct uuid_entry *u; 337 unsigned i; 338 char buf[80]; 339 340 BUG_ON(!parent); 341 down(&c->uuid_write_mutex); 342 closure_init(cl, parent); 343 344 for (i = 0; i < KEY_PTRS(k); i++) { 345 struct bio *bio = bch_bbio_alloc(c); 346 347 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 348 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 349 350 bio->bi_end_io = uuid_endio; 351 bio->bi_private = cl; 352 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 353 bch_bio_map(bio, c->uuids); 354 355 bch_submit_bbio(bio, c, k, i); 356 357 if (op != REQ_OP_WRITE) 358 break; 359 } 360 361 bch_extent_to_text(buf, sizeof(buf), k); 362 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 363 364 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 365 if (!bch_is_zero(u->uuid, 16)) 366 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 367 u - c->uuids, u->uuid, u->label, 368 u->first_reg, u->last_reg, u->invalidated); 369 370 closure_return_with_destructor(cl, uuid_io_unlock); 371 } 372 373 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 374 { 375 struct bkey *k = &j->uuid_bucket; 376 377 if (__bch_btree_ptr_invalid(c, k)) 378 return "bad uuid pointer"; 379 380 bkey_copy(&c->uuid_bucket, k); 381 uuid_io(c, REQ_OP_READ, 0, k, cl); 382 383 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 384 struct uuid_entry_v0 *u0 = (void *) c->uuids; 385 struct uuid_entry *u1 = (void *) c->uuids; 386 int i; 387 388 closure_sync(cl); 389 390 /* 391 * Since the new uuid entry is bigger than the old, we have to 392 * convert starting at the highest memory address and work down 393 * in order to do it in place 394 */ 395 396 for (i = c->nr_uuids - 1; 397 i >= 0; 398 --i) { 399 memcpy(u1[i].uuid, u0[i].uuid, 16); 400 memcpy(u1[i].label, u0[i].label, 32); 401 402 u1[i].first_reg = u0[i].first_reg; 403 u1[i].last_reg = u0[i].last_reg; 404 u1[i].invalidated = u0[i].invalidated; 405 406 u1[i].flags = 0; 407 u1[i].sectors = 0; 408 } 409 } 410 411 return NULL; 412 } 413 414 static int __uuid_write(struct cache_set *c) 415 { 416 BKEY_PADDED(key) k; 417 struct closure cl; 418 closure_init_stack(&cl); 419 420 lockdep_assert_held(&bch_register_lock); 421 422 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 423 return 1; 424 425 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 426 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 427 closure_sync(&cl); 428 429 bkey_copy(&c->uuid_bucket, &k.key); 430 bkey_put(c, &k.key); 431 return 0; 432 } 433 434 int bch_uuid_write(struct cache_set *c) 435 { 436 int ret = __uuid_write(c); 437 438 if (!ret) 439 bch_journal_meta(c, NULL); 440 441 return ret; 442 } 443 444 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 445 { 446 struct uuid_entry *u; 447 448 for (u = c->uuids; 449 u < c->uuids + c->nr_uuids; u++) 450 if (!memcmp(u->uuid, uuid, 16)) 451 return u; 452 453 return NULL; 454 } 455 456 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 457 { 458 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 459 return uuid_find(c, zero_uuid); 460 } 461 462 /* 463 * Bucket priorities/gens: 464 * 465 * For each bucket, we store on disk its 466 * 8 bit gen 467 * 16 bit priority 468 * 469 * See alloc.c for an explanation of the gen. The priority is used to implement 470 * lru (and in the future other) cache replacement policies; for most purposes 471 * it's just an opaque integer. 472 * 473 * The gens and the priorities don't have a whole lot to do with each other, and 474 * it's actually the gens that must be written out at specific times - it's no 475 * big deal if the priorities don't get written, if we lose them we just reuse 476 * buckets in suboptimal order. 477 * 478 * On disk they're stored in a packed array, and in as many buckets are required 479 * to fit them all. The buckets we use to store them form a list; the journal 480 * header points to the first bucket, the first bucket points to the second 481 * bucket, et cetera. 482 * 483 * This code is used by the allocation code; periodically (whenever it runs out 484 * of buckets to allocate from) the allocation code will invalidate some 485 * buckets, but it can't use those buckets until their new gens are safely on 486 * disk. 487 */ 488 489 static void prio_endio(struct bio *bio) 490 { 491 struct cache *ca = bio->bi_private; 492 493 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 494 bch_bbio_free(bio, ca->set); 495 closure_put(&ca->prio); 496 } 497 498 static void prio_io(struct cache *ca, uint64_t bucket, int op, 499 unsigned long op_flags) 500 { 501 struct closure *cl = &ca->prio; 502 struct bio *bio = bch_bbio_alloc(ca->set); 503 504 closure_init_stack(cl); 505 506 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 507 bio_set_dev(bio, ca->bdev); 508 bio->bi_iter.bi_size = bucket_bytes(ca); 509 510 bio->bi_end_io = prio_endio; 511 bio->bi_private = ca; 512 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 513 bch_bio_map(bio, ca->disk_buckets); 514 515 closure_bio_submit(ca->set, bio, &ca->prio); 516 closure_sync(cl); 517 } 518 519 void bch_prio_write(struct cache *ca) 520 { 521 int i; 522 struct bucket *b; 523 struct closure cl; 524 525 closure_init_stack(&cl); 526 527 lockdep_assert_held(&ca->set->bucket_lock); 528 529 ca->disk_buckets->seq++; 530 531 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 532 &ca->meta_sectors_written); 533 534 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 535 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 536 537 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 538 long bucket; 539 struct prio_set *p = ca->disk_buckets; 540 struct bucket_disk *d = p->data; 541 struct bucket_disk *end = d + prios_per_bucket(ca); 542 543 for (b = ca->buckets + i * prios_per_bucket(ca); 544 b < ca->buckets + ca->sb.nbuckets && d < end; 545 b++, d++) { 546 d->prio = cpu_to_le16(b->prio); 547 d->gen = b->gen; 548 } 549 550 p->next_bucket = ca->prio_buckets[i + 1]; 551 p->magic = pset_magic(&ca->sb); 552 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 553 554 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 555 BUG_ON(bucket == -1); 556 557 mutex_unlock(&ca->set->bucket_lock); 558 prio_io(ca, bucket, REQ_OP_WRITE, 0); 559 mutex_lock(&ca->set->bucket_lock); 560 561 ca->prio_buckets[i] = bucket; 562 atomic_dec_bug(&ca->buckets[bucket].pin); 563 } 564 565 mutex_unlock(&ca->set->bucket_lock); 566 567 bch_journal_meta(ca->set, &cl); 568 closure_sync(&cl); 569 570 mutex_lock(&ca->set->bucket_lock); 571 572 /* 573 * Don't want the old priorities to get garbage collected until after we 574 * finish writing the new ones, and they're journalled 575 */ 576 for (i = 0; i < prio_buckets(ca); i++) { 577 if (ca->prio_last_buckets[i]) 578 __bch_bucket_free(ca, 579 &ca->buckets[ca->prio_last_buckets[i]]); 580 581 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 582 } 583 } 584 585 static void prio_read(struct cache *ca, uint64_t bucket) 586 { 587 struct prio_set *p = ca->disk_buckets; 588 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 589 struct bucket *b; 590 unsigned bucket_nr = 0; 591 592 for (b = ca->buckets; 593 b < ca->buckets + ca->sb.nbuckets; 594 b++, d++) { 595 if (d == end) { 596 ca->prio_buckets[bucket_nr] = bucket; 597 ca->prio_last_buckets[bucket_nr] = bucket; 598 bucket_nr++; 599 600 prio_io(ca, bucket, REQ_OP_READ, 0); 601 602 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 603 pr_warn("bad csum reading priorities"); 604 605 if (p->magic != pset_magic(&ca->sb)) 606 pr_warn("bad magic reading priorities"); 607 608 bucket = p->next_bucket; 609 d = p->data; 610 } 611 612 b->prio = le16_to_cpu(d->prio); 613 b->gen = b->last_gc = d->gen; 614 } 615 } 616 617 /* Bcache device */ 618 619 static int open_dev(struct block_device *b, fmode_t mode) 620 { 621 struct bcache_device *d = b->bd_disk->private_data; 622 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 623 return -ENXIO; 624 625 closure_get(&d->cl); 626 return 0; 627 } 628 629 static void release_dev(struct gendisk *b, fmode_t mode) 630 { 631 struct bcache_device *d = b->private_data; 632 closure_put(&d->cl); 633 } 634 635 static int ioctl_dev(struct block_device *b, fmode_t mode, 636 unsigned int cmd, unsigned long arg) 637 { 638 struct bcache_device *d = b->bd_disk->private_data; 639 struct cached_dev *dc = container_of(d, struct cached_dev, disk); 640 641 if (dc->io_disable) 642 return -EIO; 643 644 return d->ioctl(d, mode, cmd, arg); 645 } 646 647 static const struct block_device_operations bcache_ops = { 648 .open = open_dev, 649 .release = release_dev, 650 .ioctl = ioctl_dev, 651 .owner = THIS_MODULE, 652 }; 653 654 void bcache_device_stop(struct bcache_device *d) 655 { 656 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 657 closure_queue(&d->cl); 658 } 659 660 static void bcache_device_unlink(struct bcache_device *d) 661 { 662 lockdep_assert_held(&bch_register_lock); 663 664 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 665 unsigned i; 666 struct cache *ca; 667 668 sysfs_remove_link(&d->c->kobj, d->name); 669 sysfs_remove_link(&d->kobj, "cache"); 670 671 for_each_cache(ca, d->c, i) 672 bd_unlink_disk_holder(ca->bdev, d->disk); 673 } 674 } 675 676 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 677 const char *name) 678 { 679 unsigned i; 680 struct cache *ca; 681 682 for_each_cache(ca, d->c, i) 683 bd_link_disk_holder(ca->bdev, d->disk); 684 685 snprintf(d->name, BCACHEDEVNAME_SIZE, 686 "%s%u", name, d->id); 687 688 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 689 sysfs_create_link(&c->kobj, &d->kobj, d->name), 690 "Couldn't create device <-> cache set symlinks"); 691 692 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 693 } 694 695 static void bcache_device_detach(struct bcache_device *d) 696 { 697 lockdep_assert_held(&bch_register_lock); 698 699 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 700 struct uuid_entry *u = d->c->uuids + d->id; 701 702 SET_UUID_FLASH_ONLY(u, 0); 703 memcpy(u->uuid, invalid_uuid, 16); 704 u->invalidated = cpu_to_le32(get_seconds()); 705 bch_uuid_write(d->c); 706 } 707 708 bcache_device_unlink(d); 709 710 d->c->devices[d->id] = NULL; 711 closure_put(&d->c->caching); 712 d->c = NULL; 713 } 714 715 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 716 unsigned id) 717 { 718 d->id = id; 719 d->c = c; 720 c->devices[id] = d; 721 722 if (id >= c->devices_max_used) 723 c->devices_max_used = id + 1; 724 725 closure_get(&c->caching); 726 } 727 728 static inline int first_minor_to_idx(int first_minor) 729 { 730 return (first_minor/BCACHE_MINORS); 731 } 732 733 static inline int idx_to_first_minor(int idx) 734 { 735 return (idx * BCACHE_MINORS); 736 } 737 738 static void bcache_device_free(struct bcache_device *d) 739 { 740 lockdep_assert_held(&bch_register_lock); 741 742 pr_info("%s stopped", d->disk->disk_name); 743 744 if (d->c) 745 bcache_device_detach(d); 746 if (d->disk && d->disk->flags & GENHD_FL_UP) 747 del_gendisk(d->disk); 748 if (d->disk && d->disk->queue) 749 blk_cleanup_queue(d->disk->queue); 750 if (d->disk) { 751 ida_simple_remove(&bcache_device_idx, 752 first_minor_to_idx(d->disk->first_minor)); 753 put_disk(d->disk); 754 } 755 756 bioset_exit(&d->bio_split); 757 kvfree(d->full_dirty_stripes); 758 kvfree(d->stripe_sectors_dirty); 759 760 closure_debug_destroy(&d->cl); 761 } 762 763 static int bcache_device_init(struct bcache_device *d, unsigned block_size, 764 sector_t sectors) 765 { 766 struct request_queue *q; 767 const size_t max_stripes = min_t(size_t, INT_MAX, 768 SIZE_MAX / sizeof(atomic_t)); 769 size_t n; 770 int idx; 771 772 if (!d->stripe_size) 773 d->stripe_size = 1 << 31; 774 775 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 776 777 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 778 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 779 (unsigned)d->nr_stripes); 780 return -ENOMEM; 781 } 782 783 n = d->nr_stripes * sizeof(atomic_t); 784 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 785 if (!d->stripe_sectors_dirty) 786 return -ENOMEM; 787 788 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 789 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 790 if (!d->full_dirty_stripes) 791 return -ENOMEM; 792 793 idx = ida_simple_get(&bcache_device_idx, 0, 794 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 795 if (idx < 0) 796 return idx; 797 798 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 799 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 800 !(d->disk = alloc_disk(BCACHE_MINORS))) { 801 ida_simple_remove(&bcache_device_idx, idx); 802 return -ENOMEM; 803 } 804 805 set_capacity(d->disk, sectors); 806 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 807 808 d->disk->major = bcache_major; 809 d->disk->first_minor = idx_to_first_minor(idx); 810 d->disk->fops = &bcache_ops; 811 d->disk->private_data = d; 812 813 q = blk_alloc_queue(GFP_KERNEL); 814 if (!q) 815 return -ENOMEM; 816 817 blk_queue_make_request(q, NULL); 818 d->disk->queue = q; 819 q->queuedata = d; 820 q->backing_dev_info->congested_data = d; 821 q->limits.max_hw_sectors = UINT_MAX; 822 q->limits.max_sectors = UINT_MAX; 823 q->limits.max_segment_size = UINT_MAX; 824 q->limits.max_segments = BIO_MAX_PAGES; 825 blk_queue_max_discard_sectors(q, UINT_MAX); 826 q->limits.discard_granularity = 512; 827 q->limits.io_min = block_size; 828 q->limits.logical_block_size = block_size; 829 q->limits.physical_block_size = block_size; 830 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 831 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 832 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 833 834 blk_queue_write_cache(q, true, true); 835 836 return 0; 837 } 838 839 /* Cached device */ 840 841 static void calc_cached_dev_sectors(struct cache_set *c) 842 { 843 uint64_t sectors = 0; 844 struct cached_dev *dc; 845 846 list_for_each_entry(dc, &c->cached_devs, list) 847 sectors += bdev_sectors(dc->bdev); 848 849 c->cached_dev_sectors = sectors; 850 } 851 852 #define BACKING_DEV_OFFLINE_TIMEOUT 5 853 static int cached_dev_status_update(void *arg) 854 { 855 struct cached_dev *dc = arg; 856 struct request_queue *q; 857 858 /* 859 * If this delayed worker is stopping outside, directly quit here. 860 * dc->io_disable might be set via sysfs interface, so check it 861 * here too. 862 */ 863 while (!kthread_should_stop() && !dc->io_disable) { 864 q = bdev_get_queue(dc->bdev); 865 if (blk_queue_dying(q)) 866 dc->offline_seconds++; 867 else 868 dc->offline_seconds = 0; 869 870 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 871 pr_err("%s: device offline for %d seconds", 872 dc->backing_dev_name, 873 BACKING_DEV_OFFLINE_TIMEOUT); 874 pr_err("%s: disable I/O request due to backing " 875 "device offline", dc->disk.name); 876 dc->io_disable = true; 877 /* let others know earlier that io_disable is true */ 878 smp_mb(); 879 bcache_device_stop(&dc->disk); 880 break; 881 } 882 schedule_timeout_interruptible(HZ); 883 } 884 885 wait_for_kthread_stop(); 886 return 0; 887 } 888 889 890 void bch_cached_dev_run(struct cached_dev *dc) 891 { 892 struct bcache_device *d = &dc->disk; 893 char buf[SB_LABEL_SIZE + 1]; 894 char *env[] = { 895 "DRIVER=bcache", 896 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 897 NULL, 898 NULL, 899 }; 900 901 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 902 buf[SB_LABEL_SIZE] = '\0'; 903 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 904 905 if (atomic_xchg(&dc->running, 1)) { 906 kfree(env[1]); 907 kfree(env[2]); 908 return; 909 } 910 911 if (!d->c && 912 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 913 struct closure cl; 914 closure_init_stack(&cl); 915 916 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 917 bch_write_bdev_super(dc, &cl); 918 closure_sync(&cl); 919 } 920 921 add_disk(d->disk); 922 bd_link_disk_holder(dc->bdev, dc->disk.disk); 923 /* won't show up in the uevent file, use udevadm monitor -e instead 924 * only class / kset properties are persistent */ 925 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 926 kfree(env[1]); 927 kfree(env[2]); 928 929 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 930 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 931 pr_debug("error creating sysfs link"); 932 933 dc->status_update_thread = kthread_run(cached_dev_status_update, 934 dc, "bcache_status_update"); 935 if (IS_ERR(dc->status_update_thread)) { 936 pr_warn("failed to create bcache_status_update kthread, " 937 "continue to run without monitoring backing " 938 "device status"); 939 } 940 } 941 942 /* 943 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 944 * work dc->writeback_rate_update is running. Wait until the routine 945 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 946 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 947 * seconds, give up waiting here and continue to cancel it too. 948 */ 949 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 950 { 951 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 952 953 do { 954 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 955 &dc->disk.flags)) 956 break; 957 time_out--; 958 schedule_timeout_interruptible(1); 959 } while (time_out > 0); 960 961 if (time_out == 0) 962 pr_warn("give up waiting for dc->writeback_write_update to quit"); 963 964 cancel_delayed_work_sync(&dc->writeback_rate_update); 965 } 966 967 static void cached_dev_detach_finish(struct work_struct *w) 968 { 969 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 970 struct closure cl; 971 closure_init_stack(&cl); 972 973 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 974 BUG_ON(refcount_read(&dc->count)); 975 976 mutex_lock(&bch_register_lock); 977 978 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 979 cancel_writeback_rate_update_dwork(dc); 980 981 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 982 kthread_stop(dc->writeback_thread); 983 dc->writeback_thread = NULL; 984 } 985 986 memset(&dc->sb.set_uuid, 0, 16); 987 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 988 989 bch_write_bdev_super(dc, &cl); 990 closure_sync(&cl); 991 992 bcache_device_detach(&dc->disk); 993 list_move(&dc->list, &uncached_devices); 994 995 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 996 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 997 998 mutex_unlock(&bch_register_lock); 999 1000 pr_info("Caching disabled for %s", dc->backing_dev_name); 1001 1002 /* Drop ref we took in cached_dev_detach() */ 1003 closure_put(&dc->disk.cl); 1004 } 1005 1006 void bch_cached_dev_detach(struct cached_dev *dc) 1007 { 1008 lockdep_assert_held(&bch_register_lock); 1009 1010 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1011 return; 1012 1013 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1014 return; 1015 1016 /* 1017 * Block the device from being closed and freed until we're finished 1018 * detaching 1019 */ 1020 closure_get(&dc->disk.cl); 1021 1022 bch_writeback_queue(dc); 1023 1024 cached_dev_put(dc); 1025 } 1026 1027 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1028 uint8_t *set_uuid) 1029 { 1030 uint32_t rtime = cpu_to_le32(get_seconds()); 1031 struct uuid_entry *u; 1032 struct cached_dev *exist_dc, *t; 1033 1034 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1035 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1036 return -ENOENT; 1037 1038 if (dc->disk.c) { 1039 pr_err("Can't attach %s: already attached", 1040 dc->backing_dev_name); 1041 return -EINVAL; 1042 } 1043 1044 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1045 pr_err("Can't attach %s: shutting down", 1046 dc->backing_dev_name); 1047 return -EINVAL; 1048 } 1049 1050 if (dc->sb.block_size < c->sb.block_size) { 1051 /* Will die */ 1052 pr_err("Couldn't attach %s: block size less than set's block size", 1053 dc->backing_dev_name); 1054 return -EINVAL; 1055 } 1056 1057 /* Check whether already attached */ 1058 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1059 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1060 pr_err("Tried to attach %s but duplicate UUID already attached", 1061 dc->backing_dev_name); 1062 1063 return -EINVAL; 1064 } 1065 } 1066 1067 u = uuid_find(c, dc->sb.uuid); 1068 1069 if (u && 1070 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1071 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1072 memcpy(u->uuid, invalid_uuid, 16); 1073 u->invalidated = cpu_to_le32(get_seconds()); 1074 u = NULL; 1075 } 1076 1077 if (!u) { 1078 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1079 pr_err("Couldn't find uuid for %s in set", 1080 dc->backing_dev_name); 1081 return -ENOENT; 1082 } 1083 1084 u = uuid_find_empty(c); 1085 if (!u) { 1086 pr_err("Not caching %s, no room for UUID", 1087 dc->backing_dev_name); 1088 return -EINVAL; 1089 } 1090 } 1091 1092 /* Deadlocks since we're called via sysfs... 1093 sysfs_remove_file(&dc->kobj, &sysfs_attach); 1094 */ 1095 1096 if (bch_is_zero(u->uuid, 16)) { 1097 struct closure cl; 1098 closure_init_stack(&cl); 1099 1100 memcpy(u->uuid, dc->sb.uuid, 16); 1101 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1102 u->first_reg = u->last_reg = rtime; 1103 bch_uuid_write(c); 1104 1105 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1106 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1107 1108 bch_write_bdev_super(dc, &cl); 1109 closure_sync(&cl); 1110 } else { 1111 u->last_reg = rtime; 1112 bch_uuid_write(c); 1113 } 1114 1115 bcache_device_attach(&dc->disk, c, u - c->uuids); 1116 list_move(&dc->list, &c->cached_devs); 1117 calc_cached_dev_sectors(c); 1118 1119 smp_wmb(); 1120 /* 1121 * dc->c must be set before dc->count != 0 - paired with the mb in 1122 * cached_dev_get() 1123 */ 1124 refcount_set(&dc->count, 1); 1125 1126 /* Block writeback thread, but spawn it */ 1127 down_write(&dc->writeback_lock); 1128 if (bch_cached_dev_writeback_start(dc)) { 1129 up_write(&dc->writeback_lock); 1130 return -ENOMEM; 1131 } 1132 1133 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1134 bch_sectors_dirty_init(&dc->disk); 1135 atomic_set(&dc->has_dirty, 1); 1136 bch_writeback_queue(dc); 1137 } 1138 1139 bch_cached_dev_run(dc); 1140 bcache_device_link(&dc->disk, c, "bdev"); 1141 1142 /* Allow the writeback thread to proceed */ 1143 up_write(&dc->writeback_lock); 1144 1145 pr_info("Caching %s as %s on set %pU", 1146 dc->backing_dev_name, 1147 dc->disk.disk->disk_name, 1148 dc->disk.c->sb.set_uuid); 1149 return 0; 1150 } 1151 1152 void bch_cached_dev_release(struct kobject *kobj) 1153 { 1154 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1155 disk.kobj); 1156 kfree(dc); 1157 module_put(THIS_MODULE); 1158 } 1159 1160 static void cached_dev_free(struct closure *cl) 1161 { 1162 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1163 1164 mutex_lock(&bch_register_lock); 1165 1166 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1167 cancel_writeback_rate_update_dwork(dc); 1168 1169 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1170 kthread_stop(dc->writeback_thread); 1171 if (dc->writeback_write_wq) 1172 destroy_workqueue(dc->writeback_write_wq); 1173 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1174 kthread_stop(dc->status_update_thread); 1175 1176 if (atomic_read(&dc->running)) 1177 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1178 bcache_device_free(&dc->disk); 1179 list_del(&dc->list); 1180 1181 mutex_unlock(&bch_register_lock); 1182 1183 if (!IS_ERR_OR_NULL(dc->bdev)) 1184 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1185 1186 wake_up(&unregister_wait); 1187 1188 kobject_put(&dc->disk.kobj); 1189 } 1190 1191 static void cached_dev_flush(struct closure *cl) 1192 { 1193 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1194 struct bcache_device *d = &dc->disk; 1195 1196 mutex_lock(&bch_register_lock); 1197 bcache_device_unlink(d); 1198 mutex_unlock(&bch_register_lock); 1199 1200 bch_cache_accounting_destroy(&dc->accounting); 1201 kobject_del(&d->kobj); 1202 1203 continue_at(cl, cached_dev_free, system_wq); 1204 } 1205 1206 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1207 { 1208 int ret; 1209 struct io *io; 1210 struct request_queue *q = bdev_get_queue(dc->bdev); 1211 1212 __module_get(THIS_MODULE); 1213 INIT_LIST_HEAD(&dc->list); 1214 closure_init(&dc->disk.cl, NULL); 1215 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1216 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1217 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1218 sema_init(&dc->sb_write_mutex, 1); 1219 INIT_LIST_HEAD(&dc->io_lru); 1220 spin_lock_init(&dc->io_lock); 1221 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1222 1223 dc->sequential_cutoff = 4 << 20; 1224 1225 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1226 list_add(&io->lru, &dc->io_lru); 1227 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1228 } 1229 1230 dc->disk.stripe_size = q->limits.io_opt >> 9; 1231 1232 if (dc->disk.stripe_size) 1233 dc->partial_stripes_expensive = 1234 q->limits.raid_partial_stripes_expensive; 1235 1236 ret = bcache_device_init(&dc->disk, block_size, 1237 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1238 if (ret) 1239 return ret; 1240 1241 dc->disk.disk->queue->backing_dev_info->ra_pages = 1242 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1243 q->backing_dev_info->ra_pages); 1244 1245 atomic_set(&dc->io_errors, 0); 1246 dc->io_disable = false; 1247 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1248 /* default to auto */ 1249 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1250 1251 bch_cached_dev_request_init(dc); 1252 bch_cached_dev_writeback_init(dc); 1253 return 0; 1254 } 1255 1256 /* Cached device - bcache superblock */ 1257 1258 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1259 struct block_device *bdev, 1260 struct cached_dev *dc) 1261 { 1262 const char *err = "cannot allocate memory"; 1263 struct cache_set *c; 1264 1265 bdevname(bdev, dc->backing_dev_name); 1266 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1267 dc->bdev = bdev; 1268 dc->bdev->bd_holder = dc; 1269 1270 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1271 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1272 get_page(sb_page); 1273 1274 1275 if (cached_dev_init(dc, sb->block_size << 9)) 1276 goto err; 1277 1278 err = "error creating kobject"; 1279 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1280 "bcache")) 1281 goto err; 1282 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1283 goto err; 1284 1285 pr_info("registered backing device %s", dc->backing_dev_name); 1286 1287 list_add(&dc->list, &uncached_devices); 1288 list_for_each_entry(c, &bch_cache_sets, list) 1289 bch_cached_dev_attach(dc, c, NULL); 1290 1291 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1292 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1293 bch_cached_dev_run(dc); 1294 1295 return; 1296 err: 1297 pr_notice("error %s: %s", dc->backing_dev_name, err); 1298 bcache_device_stop(&dc->disk); 1299 } 1300 1301 /* Flash only volumes */ 1302 1303 void bch_flash_dev_release(struct kobject *kobj) 1304 { 1305 struct bcache_device *d = container_of(kobj, struct bcache_device, 1306 kobj); 1307 kfree(d); 1308 } 1309 1310 static void flash_dev_free(struct closure *cl) 1311 { 1312 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1313 mutex_lock(&bch_register_lock); 1314 bcache_device_free(d); 1315 mutex_unlock(&bch_register_lock); 1316 kobject_put(&d->kobj); 1317 } 1318 1319 static void flash_dev_flush(struct closure *cl) 1320 { 1321 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1322 1323 mutex_lock(&bch_register_lock); 1324 bcache_device_unlink(d); 1325 mutex_unlock(&bch_register_lock); 1326 kobject_del(&d->kobj); 1327 continue_at(cl, flash_dev_free, system_wq); 1328 } 1329 1330 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1331 { 1332 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1333 GFP_KERNEL); 1334 if (!d) 1335 return -ENOMEM; 1336 1337 closure_init(&d->cl, NULL); 1338 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1339 1340 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1341 1342 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1343 goto err; 1344 1345 bcache_device_attach(d, c, u - c->uuids); 1346 bch_sectors_dirty_init(d); 1347 bch_flash_dev_request_init(d); 1348 add_disk(d->disk); 1349 1350 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1351 goto err; 1352 1353 bcache_device_link(d, c, "volume"); 1354 1355 return 0; 1356 err: 1357 kobject_put(&d->kobj); 1358 return -ENOMEM; 1359 } 1360 1361 static int flash_devs_run(struct cache_set *c) 1362 { 1363 int ret = 0; 1364 struct uuid_entry *u; 1365 1366 for (u = c->uuids; 1367 u < c->uuids + c->nr_uuids && !ret; 1368 u++) 1369 if (UUID_FLASH_ONLY(u)) 1370 ret = flash_dev_run(c, u); 1371 1372 return ret; 1373 } 1374 1375 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1376 { 1377 struct uuid_entry *u; 1378 1379 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1380 return -EINTR; 1381 1382 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1383 return -EPERM; 1384 1385 u = uuid_find_empty(c); 1386 if (!u) { 1387 pr_err("Can't create volume, no room for UUID"); 1388 return -EINVAL; 1389 } 1390 1391 get_random_bytes(u->uuid, 16); 1392 memset(u->label, 0, 32); 1393 u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); 1394 1395 SET_UUID_FLASH_ONLY(u, 1); 1396 u->sectors = size >> 9; 1397 1398 bch_uuid_write(c); 1399 1400 return flash_dev_run(c, u); 1401 } 1402 1403 bool bch_cached_dev_error(struct cached_dev *dc) 1404 { 1405 struct cache_set *c; 1406 1407 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1408 return false; 1409 1410 dc->io_disable = true; 1411 /* make others know io_disable is true earlier */ 1412 smp_mb(); 1413 1414 pr_err("stop %s: too many IO errors on backing device %s\n", 1415 dc->disk.disk->disk_name, dc->backing_dev_name); 1416 1417 /* 1418 * If the cached device is still attached to a cache set, 1419 * even dc->io_disable is true and no more I/O requests 1420 * accepted, cache device internal I/O (writeback scan or 1421 * garbage collection) may still prevent bcache device from 1422 * being stopped. So here CACHE_SET_IO_DISABLE should be 1423 * set to c->flags too, to make the internal I/O to cache 1424 * device rejected and stopped immediately. 1425 * If c is NULL, that means the bcache device is not attached 1426 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. 1427 */ 1428 c = dc->disk.c; 1429 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1430 pr_info("CACHE_SET_IO_DISABLE already set"); 1431 1432 bcache_device_stop(&dc->disk); 1433 return true; 1434 } 1435 1436 /* Cache set */ 1437 1438 __printf(2, 3) 1439 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1440 { 1441 va_list args; 1442 1443 if (c->on_error != ON_ERROR_PANIC && 1444 test_bit(CACHE_SET_STOPPING, &c->flags)) 1445 return false; 1446 1447 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1448 pr_info("CACHE_SET_IO_DISABLE already set"); 1449 1450 /* XXX: we can be called from atomic context 1451 acquire_console_sem(); 1452 */ 1453 1454 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1455 1456 va_start(args, fmt); 1457 vprintk(fmt, args); 1458 va_end(args); 1459 1460 printk(", disabling caching\n"); 1461 1462 if (c->on_error == ON_ERROR_PANIC) 1463 panic("panic forced after error\n"); 1464 1465 bch_cache_set_unregister(c); 1466 return true; 1467 } 1468 1469 void bch_cache_set_release(struct kobject *kobj) 1470 { 1471 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1472 kfree(c); 1473 module_put(THIS_MODULE); 1474 } 1475 1476 static void cache_set_free(struct closure *cl) 1477 { 1478 struct cache_set *c = container_of(cl, struct cache_set, cl); 1479 struct cache *ca; 1480 unsigned i; 1481 1482 if (!IS_ERR_OR_NULL(c->debug)) 1483 debugfs_remove(c->debug); 1484 1485 bch_open_buckets_free(c); 1486 bch_btree_cache_free(c); 1487 bch_journal_free(c); 1488 1489 for_each_cache(ca, c, i) 1490 if (ca) { 1491 ca->set = NULL; 1492 c->cache[ca->sb.nr_this_dev] = NULL; 1493 kobject_put(&ca->kobj); 1494 } 1495 1496 bch_bset_sort_state_free(&c->sort); 1497 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1498 1499 if (c->moving_gc_wq) 1500 destroy_workqueue(c->moving_gc_wq); 1501 bioset_exit(&c->bio_split); 1502 mempool_exit(&c->fill_iter); 1503 mempool_exit(&c->bio_meta); 1504 mempool_exit(&c->search); 1505 kfree(c->devices); 1506 1507 mutex_lock(&bch_register_lock); 1508 list_del(&c->list); 1509 mutex_unlock(&bch_register_lock); 1510 1511 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1512 wake_up(&unregister_wait); 1513 1514 closure_debug_destroy(&c->cl); 1515 kobject_put(&c->kobj); 1516 } 1517 1518 static void cache_set_flush(struct closure *cl) 1519 { 1520 struct cache_set *c = container_of(cl, struct cache_set, caching); 1521 struct cache *ca; 1522 struct btree *b; 1523 unsigned i; 1524 1525 bch_cache_accounting_destroy(&c->accounting); 1526 1527 kobject_put(&c->internal); 1528 kobject_del(&c->kobj); 1529 1530 if (c->gc_thread) 1531 kthread_stop(c->gc_thread); 1532 1533 if (!IS_ERR_OR_NULL(c->root)) 1534 list_add(&c->root->list, &c->btree_cache); 1535 1536 /* Should skip this if we're unregistering because of an error */ 1537 list_for_each_entry(b, &c->btree_cache, list) { 1538 mutex_lock(&b->write_lock); 1539 if (btree_node_dirty(b)) 1540 __bch_btree_node_write(b, NULL); 1541 mutex_unlock(&b->write_lock); 1542 } 1543 1544 for_each_cache(ca, c, i) 1545 if (ca->alloc_thread) 1546 kthread_stop(ca->alloc_thread); 1547 1548 if (c->journal.cur) { 1549 cancel_delayed_work_sync(&c->journal.work); 1550 /* flush last journal entry if needed */ 1551 c->journal.work.work.func(&c->journal.work.work); 1552 } 1553 1554 closure_return(cl); 1555 } 1556 1557 /* 1558 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1559 * cache set is unregistering due to too many I/O errors. In this condition, 1560 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1561 * value and whether the broken cache has dirty data: 1562 * 1563 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1564 * BCH_CACHED_STOP_AUTO 0 NO 1565 * BCH_CACHED_STOP_AUTO 1 YES 1566 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1567 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1568 * 1569 * The expected behavior is, if stop_when_cache_set_failed is configured to 1570 * "auto" via sysfs interface, the bcache device will not be stopped if the 1571 * backing device is clean on the broken cache device. 1572 */ 1573 static void conditional_stop_bcache_device(struct cache_set *c, 1574 struct bcache_device *d, 1575 struct cached_dev *dc) 1576 { 1577 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1578 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1579 d->disk->disk_name, c->sb.set_uuid); 1580 bcache_device_stop(d); 1581 } else if (atomic_read(&dc->has_dirty)) { 1582 /* 1583 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1584 * and dc->has_dirty == 1 1585 */ 1586 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1587 d->disk->disk_name); 1588 /* 1589 * There might be a small time gap that cache set is 1590 * released but bcache device is not. Inside this time 1591 * gap, regular I/O requests will directly go into 1592 * backing device as no cache set attached to. This 1593 * behavior may also introduce potential inconsistence 1594 * data in writeback mode while cache is dirty. 1595 * Therefore before calling bcache_device_stop() due 1596 * to a broken cache device, dc->io_disable should be 1597 * explicitly set to true. 1598 */ 1599 dc->io_disable = true; 1600 /* make others know io_disable is true earlier */ 1601 smp_mb(); 1602 bcache_device_stop(d); 1603 } else { 1604 /* 1605 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1606 * and dc->has_dirty == 0 1607 */ 1608 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1609 d->disk->disk_name); 1610 } 1611 } 1612 1613 static void __cache_set_unregister(struct closure *cl) 1614 { 1615 struct cache_set *c = container_of(cl, struct cache_set, caching); 1616 struct cached_dev *dc; 1617 struct bcache_device *d; 1618 size_t i; 1619 1620 mutex_lock(&bch_register_lock); 1621 1622 for (i = 0; i < c->devices_max_used; i++) { 1623 d = c->devices[i]; 1624 if (!d) 1625 continue; 1626 1627 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1628 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1629 dc = container_of(d, struct cached_dev, disk); 1630 bch_cached_dev_detach(dc); 1631 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1632 conditional_stop_bcache_device(c, d, dc); 1633 } else { 1634 bcache_device_stop(d); 1635 } 1636 } 1637 1638 mutex_unlock(&bch_register_lock); 1639 1640 continue_at(cl, cache_set_flush, system_wq); 1641 } 1642 1643 void bch_cache_set_stop(struct cache_set *c) 1644 { 1645 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1646 closure_queue(&c->caching); 1647 } 1648 1649 void bch_cache_set_unregister(struct cache_set *c) 1650 { 1651 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1652 bch_cache_set_stop(c); 1653 } 1654 1655 #define alloc_bucket_pages(gfp, c) \ 1656 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1657 1658 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1659 { 1660 int iter_size; 1661 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1662 if (!c) 1663 return NULL; 1664 1665 __module_get(THIS_MODULE); 1666 closure_init(&c->cl, NULL); 1667 set_closure_fn(&c->cl, cache_set_free, system_wq); 1668 1669 closure_init(&c->caching, &c->cl); 1670 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1671 1672 /* Maybe create continue_at_noreturn() and use it here? */ 1673 closure_set_stopped(&c->cl); 1674 closure_put(&c->cl); 1675 1676 kobject_init(&c->kobj, &bch_cache_set_ktype); 1677 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1678 1679 bch_cache_accounting_init(&c->accounting, &c->cl); 1680 1681 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1682 c->sb.block_size = sb->block_size; 1683 c->sb.bucket_size = sb->bucket_size; 1684 c->sb.nr_in_set = sb->nr_in_set; 1685 c->sb.last_mount = sb->last_mount; 1686 c->bucket_bits = ilog2(sb->bucket_size); 1687 c->block_bits = ilog2(sb->block_size); 1688 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1689 c->devices_max_used = 0; 1690 c->btree_pages = bucket_pages(c); 1691 if (c->btree_pages > BTREE_MAX_PAGES) 1692 c->btree_pages = max_t(int, c->btree_pages / 4, 1693 BTREE_MAX_PAGES); 1694 1695 sema_init(&c->sb_write_mutex, 1); 1696 mutex_init(&c->bucket_lock); 1697 init_waitqueue_head(&c->btree_cache_wait); 1698 init_waitqueue_head(&c->bucket_wait); 1699 init_waitqueue_head(&c->gc_wait); 1700 sema_init(&c->uuid_write_mutex, 1); 1701 1702 spin_lock_init(&c->btree_gc_time.lock); 1703 spin_lock_init(&c->btree_split_time.lock); 1704 spin_lock_init(&c->btree_read_time.lock); 1705 1706 bch_moving_init_cache_set(c); 1707 1708 INIT_LIST_HEAD(&c->list); 1709 INIT_LIST_HEAD(&c->cached_devs); 1710 INIT_LIST_HEAD(&c->btree_cache); 1711 INIT_LIST_HEAD(&c->btree_cache_freeable); 1712 INIT_LIST_HEAD(&c->btree_cache_freed); 1713 INIT_LIST_HEAD(&c->data_buckets); 1714 1715 iter_size = (sb->bucket_size / sb->block_size + 1) * 1716 sizeof(struct btree_iter_set); 1717 1718 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1719 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1720 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1721 sizeof(struct bbio) + sizeof(struct bio_vec) * 1722 bucket_pages(c)) || 1723 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1724 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1725 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1726 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1727 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1728 WQ_MEM_RECLAIM, 0)) || 1729 bch_journal_alloc(c) || 1730 bch_btree_cache_alloc(c) || 1731 bch_open_buckets_alloc(c) || 1732 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1733 goto err; 1734 1735 c->congested_read_threshold_us = 2000; 1736 c->congested_write_threshold_us = 20000; 1737 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1738 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1739 1740 return c; 1741 err: 1742 bch_cache_set_unregister(c); 1743 return NULL; 1744 } 1745 1746 static void run_cache_set(struct cache_set *c) 1747 { 1748 const char *err = "cannot allocate memory"; 1749 struct cached_dev *dc, *t; 1750 struct cache *ca; 1751 struct closure cl; 1752 unsigned i; 1753 1754 closure_init_stack(&cl); 1755 1756 for_each_cache(ca, c, i) 1757 c->nbuckets += ca->sb.nbuckets; 1758 set_gc_sectors(c); 1759 1760 if (CACHE_SYNC(&c->sb)) { 1761 LIST_HEAD(journal); 1762 struct bkey *k; 1763 struct jset *j; 1764 1765 err = "cannot allocate memory for journal"; 1766 if (bch_journal_read(c, &journal)) 1767 goto err; 1768 1769 pr_debug("btree_journal_read() done"); 1770 1771 err = "no journal entries found"; 1772 if (list_empty(&journal)) 1773 goto err; 1774 1775 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1776 1777 err = "IO error reading priorities"; 1778 for_each_cache(ca, c, i) 1779 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1780 1781 /* 1782 * If prio_read() fails it'll call cache_set_error and we'll 1783 * tear everything down right away, but if we perhaps checked 1784 * sooner we could avoid journal replay. 1785 */ 1786 1787 k = &j->btree_root; 1788 1789 err = "bad btree root"; 1790 if (__bch_btree_ptr_invalid(c, k)) 1791 goto err; 1792 1793 err = "error reading btree root"; 1794 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1795 if (IS_ERR_OR_NULL(c->root)) 1796 goto err; 1797 1798 list_del_init(&c->root->list); 1799 rw_unlock(true, c->root); 1800 1801 err = uuid_read(c, j, &cl); 1802 if (err) 1803 goto err; 1804 1805 err = "error in recovery"; 1806 if (bch_btree_check(c)) 1807 goto err; 1808 1809 bch_journal_mark(c, &journal); 1810 bch_initial_gc_finish(c); 1811 pr_debug("btree_check() done"); 1812 1813 /* 1814 * bcache_journal_next() can't happen sooner, or 1815 * btree_gc_finish() will give spurious errors about last_gc > 1816 * gc_gen - this is a hack but oh well. 1817 */ 1818 bch_journal_next(&c->journal); 1819 1820 err = "error starting allocator thread"; 1821 for_each_cache(ca, c, i) 1822 if (bch_cache_allocator_start(ca)) 1823 goto err; 1824 1825 /* 1826 * First place it's safe to allocate: btree_check() and 1827 * btree_gc_finish() have to run before we have buckets to 1828 * allocate, and bch_bucket_alloc_set() might cause a journal 1829 * entry to be written so bcache_journal_next() has to be called 1830 * first. 1831 * 1832 * If the uuids were in the old format we have to rewrite them 1833 * before the next journal entry is written: 1834 */ 1835 if (j->version < BCACHE_JSET_VERSION_UUID) 1836 __uuid_write(c); 1837 1838 bch_journal_replay(c, &journal); 1839 } else { 1840 pr_notice("invalidating existing data"); 1841 1842 for_each_cache(ca, c, i) { 1843 unsigned j; 1844 1845 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1846 2, SB_JOURNAL_BUCKETS); 1847 1848 for (j = 0; j < ca->sb.keys; j++) 1849 ca->sb.d[j] = ca->sb.first_bucket + j; 1850 } 1851 1852 bch_initial_gc_finish(c); 1853 1854 err = "error starting allocator thread"; 1855 for_each_cache(ca, c, i) 1856 if (bch_cache_allocator_start(ca)) 1857 goto err; 1858 1859 mutex_lock(&c->bucket_lock); 1860 for_each_cache(ca, c, i) 1861 bch_prio_write(ca); 1862 mutex_unlock(&c->bucket_lock); 1863 1864 err = "cannot allocate new UUID bucket"; 1865 if (__uuid_write(c)) 1866 goto err; 1867 1868 err = "cannot allocate new btree root"; 1869 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1870 if (IS_ERR_OR_NULL(c->root)) 1871 goto err; 1872 1873 mutex_lock(&c->root->write_lock); 1874 bkey_copy_key(&c->root->key, &MAX_KEY); 1875 bch_btree_node_write(c->root, &cl); 1876 mutex_unlock(&c->root->write_lock); 1877 1878 bch_btree_set_root(c->root); 1879 rw_unlock(true, c->root); 1880 1881 /* 1882 * We don't want to write the first journal entry until 1883 * everything is set up - fortunately journal entries won't be 1884 * written until the SET_CACHE_SYNC() here: 1885 */ 1886 SET_CACHE_SYNC(&c->sb, true); 1887 1888 bch_journal_next(&c->journal); 1889 bch_journal_meta(c, &cl); 1890 } 1891 1892 err = "error starting gc thread"; 1893 if (bch_gc_thread_start(c)) 1894 goto err; 1895 1896 closure_sync(&cl); 1897 c->sb.last_mount = get_seconds(); 1898 bcache_write_super(c); 1899 1900 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1901 bch_cached_dev_attach(dc, c, NULL); 1902 1903 flash_devs_run(c); 1904 1905 set_bit(CACHE_SET_RUNNING, &c->flags); 1906 return; 1907 err: 1908 closure_sync(&cl); 1909 /* XXX: test this, it's broken */ 1910 bch_cache_set_error(c, "%s", err); 1911 } 1912 1913 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1914 { 1915 return ca->sb.block_size == c->sb.block_size && 1916 ca->sb.bucket_size == c->sb.bucket_size && 1917 ca->sb.nr_in_set == c->sb.nr_in_set; 1918 } 1919 1920 static const char *register_cache_set(struct cache *ca) 1921 { 1922 char buf[12]; 1923 const char *err = "cannot allocate memory"; 1924 struct cache_set *c; 1925 1926 list_for_each_entry(c, &bch_cache_sets, list) 1927 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1928 if (c->cache[ca->sb.nr_this_dev]) 1929 return "duplicate cache set member"; 1930 1931 if (!can_attach_cache(ca, c)) 1932 return "cache sb does not match set"; 1933 1934 if (!CACHE_SYNC(&ca->sb)) 1935 SET_CACHE_SYNC(&c->sb, false); 1936 1937 goto found; 1938 } 1939 1940 c = bch_cache_set_alloc(&ca->sb); 1941 if (!c) 1942 return err; 1943 1944 err = "error creating kobject"; 1945 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1946 kobject_add(&c->internal, &c->kobj, "internal")) 1947 goto err; 1948 1949 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1950 goto err; 1951 1952 bch_debug_init_cache_set(c); 1953 1954 list_add(&c->list, &bch_cache_sets); 1955 found: 1956 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1957 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1958 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1959 goto err; 1960 1961 if (ca->sb.seq > c->sb.seq) { 1962 c->sb.version = ca->sb.version; 1963 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1964 c->sb.flags = ca->sb.flags; 1965 c->sb.seq = ca->sb.seq; 1966 pr_debug("set version = %llu", c->sb.version); 1967 } 1968 1969 kobject_get(&ca->kobj); 1970 ca->set = c; 1971 ca->set->cache[ca->sb.nr_this_dev] = ca; 1972 c->cache_by_alloc[c->caches_loaded++] = ca; 1973 1974 if (c->caches_loaded == c->sb.nr_in_set) 1975 run_cache_set(c); 1976 1977 return NULL; 1978 err: 1979 bch_cache_set_unregister(c); 1980 return err; 1981 } 1982 1983 /* Cache device */ 1984 1985 void bch_cache_release(struct kobject *kobj) 1986 { 1987 struct cache *ca = container_of(kobj, struct cache, kobj); 1988 unsigned i; 1989 1990 if (ca->set) { 1991 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 1992 ca->set->cache[ca->sb.nr_this_dev] = NULL; 1993 } 1994 1995 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 1996 kfree(ca->prio_buckets); 1997 vfree(ca->buckets); 1998 1999 free_heap(&ca->heap); 2000 free_fifo(&ca->free_inc); 2001 2002 for (i = 0; i < RESERVE_NR; i++) 2003 free_fifo(&ca->free[i]); 2004 2005 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2006 put_page(bio_first_page_all(&ca->sb_bio)); 2007 2008 if (!IS_ERR_OR_NULL(ca->bdev)) 2009 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2010 2011 kfree(ca); 2012 module_put(THIS_MODULE); 2013 } 2014 2015 static int cache_alloc(struct cache *ca) 2016 { 2017 size_t free; 2018 size_t btree_buckets; 2019 struct bucket *b; 2020 2021 __module_get(THIS_MODULE); 2022 kobject_init(&ca->kobj, &bch_cache_ktype); 2023 2024 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2025 2026 /* 2027 * when ca->sb.njournal_buckets is not zero, journal exists, 2028 * and in bch_journal_replay(), tree node may split, 2029 * so bucket of RESERVE_BTREE type is needed, 2030 * the worst situation is all journal buckets are valid journal, 2031 * and all the keys need to replay, 2032 * so the number of RESERVE_BTREE type buckets should be as much 2033 * as journal buckets 2034 */ 2035 btree_buckets = ca->sb.njournal_buckets ?: 8; 2036 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2037 2038 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) || 2039 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 2040 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 2041 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 2042 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 2043 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 2044 !(ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2045 ca->sb.nbuckets))) || 2046 !(ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2047 prio_buckets(ca), 2), 2048 GFP_KERNEL)) || 2049 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 2050 return -ENOMEM; 2051 2052 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2053 2054 for_each_bucket(b, ca) 2055 atomic_set(&b->pin, 0); 2056 2057 return 0; 2058 } 2059 2060 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2061 struct block_device *bdev, struct cache *ca) 2062 { 2063 const char *err = NULL; /* must be set for any error case */ 2064 int ret = 0; 2065 2066 bdevname(bdev, ca->cache_dev_name); 2067 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2068 ca->bdev = bdev; 2069 ca->bdev->bd_holder = ca; 2070 2071 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2072 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2073 get_page(sb_page); 2074 2075 if (blk_queue_discard(bdev_get_queue(bdev))) 2076 ca->discard = CACHE_DISCARD(&ca->sb); 2077 2078 ret = cache_alloc(ca); 2079 if (ret != 0) { 2080 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2081 if (ret == -ENOMEM) 2082 err = "cache_alloc(): -ENOMEM"; 2083 else 2084 err = "cache_alloc(): unknown error"; 2085 goto err; 2086 } 2087 2088 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 2089 err = "error calling kobject_add"; 2090 ret = -ENOMEM; 2091 goto out; 2092 } 2093 2094 mutex_lock(&bch_register_lock); 2095 err = register_cache_set(ca); 2096 mutex_unlock(&bch_register_lock); 2097 2098 if (err) { 2099 ret = -ENODEV; 2100 goto out; 2101 } 2102 2103 pr_info("registered cache device %s", ca->cache_dev_name); 2104 2105 out: 2106 kobject_put(&ca->kobj); 2107 2108 err: 2109 if (err) 2110 pr_notice("error %s: %s", ca->cache_dev_name, err); 2111 2112 return ret; 2113 } 2114 2115 /* Global interfaces/init */ 2116 2117 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 2118 const char *, size_t); 2119 2120 kobj_attribute_write(register, register_bcache); 2121 kobj_attribute_write(register_quiet, register_bcache); 2122 2123 static bool bch_is_open_backing(struct block_device *bdev) { 2124 struct cache_set *c, *tc; 2125 struct cached_dev *dc, *t; 2126 2127 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2128 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2129 if (dc->bdev == bdev) 2130 return true; 2131 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2132 if (dc->bdev == bdev) 2133 return true; 2134 return false; 2135 } 2136 2137 static bool bch_is_open_cache(struct block_device *bdev) { 2138 struct cache_set *c, *tc; 2139 struct cache *ca; 2140 unsigned i; 2141 2142 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2143 for_each_cache(ca, c, i) 2144 if (ca->bdev == bdev) 2145 return true; 2146 return false; 2147 } 2148 2149 static bool bch_is_open(struct block_device *bdev) { 2150 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2151 } 2152 2153 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2154 const char *buffer, size_t size) 2155 { 2156 ssize_t ret = size; 2157 const char *err = "cannot allocate memory"; 2158 char *path = NULL; 2159 struct cache_sb *sb = NULL; 2160 struct block_device *bdev = NULL; 2161 struct page *sb_page = NULL; 2162 2163 if (!try_module_get(THIS_MODULE)) 2164 return -EBUSY; 2165 2166 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || 2167 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) 2168 goto err; 2169 2170 err = "failed to open device"; 2171 bdev = blkdev_get_by_path(strim(path), 2172 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2173 sb); 2174 if (IS_ERR(bdev)) { 2175 if (bdev == ERR_PTR(-EBUSY)) { 2176 bdev = lookup_bdev(strim(path)); 2177 mutex_lock(&bch_register_lock); 2178 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2179 err = "device already registered"; 2180 else 2181 err = "device busy"; 2182 mutex_unlock(&bch_register_lock); 2183 if (!IS_ERR(bdev)) 2184 bdput(bdev); 2185 if (attr == &ksysfs_register_quiet) 2186 goto out; 2187 } 2188 goto err; 2189 } 2190 2191 err = "failed to set blocksize"; 2192 if (set_blocksize(bdev, 4096)) 2193 goto err_close; 2194 2195 err = read_super(sb, bdev, &sb_page); 2196 if (err) 2197 goto err_close; 2198 2199 err = "failed to register device"; 2200 if (SB_IS_BDEV(sb)) { 2201 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2202 if (!dc) 2203 goto err_close; 2204 2205 mutex_lock(&bch_register_lock); 2206 register_bdev(sb, sb_page, bdev, dc); 2207 mutex_unlock(&bch_register_lock); 2208 } else { 2209 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2210 if (!ca) 2211 goto err_close; 2212 2213 if (register_cache(sb, sb_page, bdev, ca) != 0) 2214 goto err; 2215 } 2216 out: 2217 if (sb_page) 2218 put_page(sb_page); 2219 kfree(sb); 2220 kfree(path); 2221 module_put(THIS_MODULE); 2222 return ret; 2223 2224 err_close: 2225 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2226 err: 2227 pr_info("error %s: %s", path, err); 2228 ret = -EINVAL; 2229 goto out; 2230 } 2231 2232 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2233 { 2234 if (code == SYS_DOWN || 2235 code == SYS_HALT || 2236 code == SYS_POWER_OFF) { 2237 DEFINE_WAIT(wait); 2238 unsigned long start = jiffies; 2239 bool stopped = false; 2240 2241 struct cache_set *c, *tc; 2242 struct cached_dev *dc, *tdc; 2243 2244 mutex_lock(&bch_register_lock); 2245 2246 if (list_empty(&bch_cache_sets) && 2247 list_empty(&uncached_devices)) 2248 goto out; 2249 2250 pr_info("Stopping all devices:"); 2251 2252 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2253 bch_cache_set_stop(c); 2254 2255 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2256 bcache_device_stop(&dc->disk); 2257 2258 /* What's a condition variable? */ 2259 while (1) { 2260 long timeout = start + 2 * HZ - jiffies; 2261 2262 stopped = list_empty(&bch_cache_sets) && 2263 list_empty(&uncached_devices); 2264 2265 if (timeout < 0 || stopped) 2266 break; 2267 2268 prepare_to_wait(&unregister_wait, &wait, 2269 TASK_UNINTERRUPTIBLE); 2270 2271 mutex_unlock(&bch_register_lock); 2272 schedule_timeout(timeout); 2273 mutex_lock(&bch_register_lock); 2274 } 2275 2276 finish_wait(&unregister_wait, &wait); 2277 2278 if (stopped) 2279 pr_info("All devices stopped"); 2280 else 2281 pr_notice("Timeout waiting for devices to be closed"); 2282 out: 2283 mutex_unlock(&bch_register_lock); 2284 } 2285 2286 return NOTIFY_DONE; 2287 } 2288 2289 static struct notifier_block reboot = { 2290 .notifier_call = bcache_reboot, 2291 .priority = INT_MAX, /* before any real devices */ 2292 }; 2293 2294 static void bcache_exit(void) 2295 { 2296 bch_debug_exit(); 2297 bch_request_exit(); 2298 if (bcache_kobj) 2299 kobject_put(bcache_kobj); 2300 if (bcache_wq) 2301 destroy_workqueue(bcache_wq); 2302 if (bcache_major) 2303 unregister_blkdev(bcache_major, "bcache"); 2304 unregister_reboot_notifier(&reboot); 2305 mutex_destroy(&bch_register_lock); 2306 } 2307 2308 static int __init bcache_init(void) 2309 { 2310 static const struct attribute *files[] = { 2311 &ksysfs_register.attr, 2312 &ksysfs_register_quiet.attr, 2313 NULL 2314 }; 2315 2316 mutex_init(&bch_register_lock); 2317 init_waitqueue_head(&unregister_wait); 2318 register_reboot_notifier(&reboot); 2319 2320 bcache_major = register_blkdev(0, "bcache"); 2321 if (bcache_major < 0) { 2322 unregister_reboot_notifier(&reboot); 2323 mutex_destroy(&bch_register_lock); 2324 return bcache_major; 2325 } 2326 2327 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) || 2328 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || 2329 bch_request_init() || 2330 bch_debug_init(bcache_kobj) || closure_debug_init() || 2331 sysfs_create_files(bcache_kobj, files)) 2332 goto err; 2333 2334 return 0; 2335 err: 2336 bcache_exit(); 2337 return -ENOMEM; 2338 } 2339 2340 module_exit(bcache_exit); 2341 module_init(bcache_init); 2342