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 = (u32)ktime_get_real_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 atomic_dec(&d->c->attached_dev_nr); 700 701 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 702 struct uuid_entry *u = d->c->uuids + d->id; 703 704 SET_UUID_FLASH_ONLY(u, 0); 705 memcpy(u->uuid, invalid_uuid, 16); 706 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 707 bch_uuid_write(d->c); 708 } 709 710 bcache_device_unlink(d); 711 712 d->c->devices[d->id] = NULL; 713 closure_put(&d->c->caching); 714 d->c = NULL; 715 } 716 717 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 718 unsigned id) 719 { 720 d->id = id; 721 d->c = c; 722 c->devices[id] = d; 723 724 if (id >= c->devices_max_used) 725 c->devices_max_used = id + 1; 726 727 closure_get(&c->caching); 728 } 729 730 static inline int first_minor_to_idx(int first_minor) 731 { 732 return (first_minor/BCACHE_MINORS); 733 } 734 735 static inline int idx_to_first_minor(int idx) 736 { 737 return (idx * BCACHE_MINORS); 738 } 739 740 static void bcache_device_free(struct bcache_device *d) 741 { 742 lockdep_assert_held(&bch_register_lock); 743 744 pr_info("%s stopped", d->disk->disk_name); 745 746 if (d->c) 747 bcache_device_detach(d); 748 if (d->disk && d->disk->flags & GENHD_FL_UP) 749 del_gendisk(d->disk); 750 if (d->disk && d->disk->queue) 751 blk_cleanup_queue(d->disk->queue); 752 if (d->disk) { 753 ida_simple_remove(&bcache_device_idx, 754 first_minor_to_idx(d->disk->first_minor)); 755 put_disk(d->disk); 756 } 757 758 bioset_exit(&d->bio_split); 759 kvfree(d->full_dirty_stripes); 760 kvfree(d->stripe_sectors_dirty); 761 762 closure_debug_destroy(&d->cl); 763 } 764 765 static int bcache_device_init(struct bcache_device *d, unsigned block_size, 766 sector_t sectors) 767 { 768 struct request_queue *q; 769 const size_t max_stripes = min_t(size_t, INT_MAX, 770 SIZE_MAX / sizeof(atomic_t)); 771 size_t n; 772 int idx; 773 774 if (!d->stripe_size) 775 d->stripe_size = 1 << 31; 776 777 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 778 779 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 780 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 781 (unsigned)d->nr_stripes); 782 return -ENOMEM; 783 } 784 785 n = d->nr_stripes * sizeof(atomic_t); 786 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 787 if (!d->stripe_sectors_dirty) 788 return -ENOMEM; 789 790 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 791 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 792 if (!d->full_dirty_stripes) 793 return -ENOMEM; 794 795 idx = ida_simple_get(&bcache_device_idx, 0, 796 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 797 if (idx < 0) 798 return idx; 799 800 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 801 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) 802 goto err; 803 804 d->disk = alloc_disk(BCACHE_MINORS); 805 if (!d->disk) 806 goto err; 807 808 set_capacity(d->disk, sectors); 809 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 810 811 d->disk->major = bcache_major; 812 d->disk->first_minor = idx_to_first_minor(idx); 813 d->disk->fops = &bcache_ops; 814 d->disk->private_data = d; 815 816 q = blk_alloc_queue(GFP_KERNEL); 817 if (!q) 818 return -ENOMEM; 819 820 blk_queue_make_request(q, NULL); 821 d->disk->queue = q; 822 q->queuedata = d; 823 q->backing_dev_info->congested_data = d; 824 q->limits.max_hw_sectors = UINT_MAX; 825 q->limits.max_sectors = UINT_MAX; 826 q->limits.max_segment_size = UINT_MAX; 827 q->limits.max_segments = BIO_MAX_PAGES; 828 blk_queue_max_discard_sectors(q, UINT_MAX); 829 q->limits.discard_granularity = 512; 830 q->limits.io_min = block_size; 831 q->limits.logical_block_size = block_size; 832 q->limits.physical_block_size = block_size; 833 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 834 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 835 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 836 837 blk_queue_write_cache(q, true, true); 838 839 return 0; 840 841 err: 842 ida_simple_remove(&bcache_device_idx, idx); 843 return -ENOMEM; 844 845 } 846 847 /* Cached device */ 848 849 static void calc_cached_dev_sectors(struct cache_set *c) 850 { 851 uint64_t sectors = 0; 852 struct cached_dev *dc; 853 854 list_for_each_entry(dc, &c->cached_devs, list) 855 sectors += bdev_sectors(dc->bdev); 856 857 c->cached_dev_sectors = sectors; 858 } 859 860 #define BACKING_DEV_OFFLINE_TIMEOUT 5 861 static int cached_dev_status_update(void *arg) 862 { 863 struct cached_dev *dc = arg; 864 struct request_queue *q; 865 866 /* 867 * If this delayed worker is stopping outside, directly quit here. 868 * dc->io_disable might be set via sysfs interface, so check it 869 * here too. 870 */ 871 while (!kthread_should_stop() && !dc->io_disable) { 872 q = bdev_get_queue(dc->bdev); 873 if (blk_queue_dying(q)) 874 dc->offline_seconds++; 875 else 876 dc->offline_seconds = 0; 877 878 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 879 pr_err("%s: device offline for %d seconds", 880 dc->backing_dev_name, 881 BACKING_DEV_OFFLINE_TIMEOUT); 882 pr_err("%s: disable I/O request due to backing " 883 "device offline", dc->disk.name); 884 dc->io_disable = true; 885 /* let others know earlier that io_disable is true */ 886 smp_mb(); 887 bcache_device_stop(&dc->disk); 888 break; 889 } 890 schedule_timeout_interruptible(HZ); 891 } 892 893 wait_for_kthread_stop(); 894 return 0; 895 } 896 897 898 void bch_cached_dev_run(struct cached_dev *dc) 899 { 900 struct bcache_device *d = &dc->disk; 901 char buf[SB_LABEL_SIZE + 1]; 902 char *env[] = { 903 "DRIVER=bcache", 904 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 905 NULL, 906 NULL, 907 }; 908 909 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 910 buf[SB_LABEL_SIZE] = '\0'; 911 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 912 913 if (atomic_xchg(&dc->running, 1)) { 914 kfree(env[1]); 915 kfree(env[2]); 916 return; 917 } 918 919 if (!d->c && 920 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 921 struct closure cl; 922 closure_init_stack(&cl); 923 924 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 925 bch_write_bdev_super(dc, &cl); 926 closure_sync(&cl); 927 } 928 929 add_disk(d->disk); 930 bd_link_disk_holder(dc->bdev, dc->disk.disk); 931 /* won't show up in the uevent file, use udevadm monitor -e instead 932 * only class / kset properties are persistent */ 933 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 934 kfree(env[1]); 935 kfree(env[2]); 936 937 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 938 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 939 pr_debug("error creating sysfs link"); 940 941 dc->status_update_thread = kthread_run(cached_dev_status_update, 942 dc, "bcache_status_update"); 943 if (IS_ERR(dc->status_update_thread)) { 944 pr_warn("failed to create bcache_status_update kthread, " 945 "continue to run without monitoring backing " 946 "device status"); 947 } 948 } 949 950 /* 951 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 952 * work dc->writeback_rate_update is running. Wait until the routine 953 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 954 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 955 * seconds, give up waiting here and continue to cancel it too. 956 */ 957 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 958 { 959 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 960 961 do { 962 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 963 &dc->disk.flags)) 964 break; 965 time_out--; 966 schedule_timeout_interruptible(1); 967 } while (time_out > 0); 968 969 if (time_out == 0) 970 pr_warn("give up waiting for dc->writeback_write_update to quit"); 971 972 cancel_delayed_work_sync(&dc->writeback_rate_update); 973 } 974 975 static void cached_dev_detach_finish(struct work_struct *w) 976 { 977 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 978 struct closure cl; 979 closure_init_stack(&cl); 980 981 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 982 BUG_ON(refcount_read(&dc->count)); 983 984 mutex_lock(&bch_register_lock); 985 986 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 987 cancel_writeback_rate_update_dwork(dc); 988 989 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 990 kthread_stop(dc->writeback_thread); 991 dc->writeback_thread = NULL; 992 } 993 994 memset(&dc->sb.set_uuid, 0, 16); 995 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 996 997 bch_write_bdev_super(dc, &cl); 998 closure_sync(&cl); 999 1000 bcache_device_detach(&dc->disk); 1001 list_move(&dc->list, &uncached_devices); 1002 1003 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1004 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1005 1006 mutex_unlock(&bch_register_lock); 1007 1008 pr_info("Caching disabled for %s", dc->backing_dev_name); 1009 1010 /* Drop ref we took in cached_dev_detach() */ 1011 closure_put(&dc->disk.cl); 1012 } 1013 1014 void bch_cached_dev_detach(struct cached_dev *dc) 1015 { 1016 lockdep_assert_held(&bch_register_lock); 1017 1018 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1019 return; 1020 1021 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1022 return; 1023 1024 /* 1025 * Block the device from being closed and freed until we're finished 1026 * detaching 1027 */ 1028 closure_get(&dc->disk.cl); 1029 1030 bch_writeback_queue(dc); 1031 1032 cached_dev_put(dc); 1033 } 1034 1035 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1036 uint8_t *set_uuid) 1037 { 1038 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); 1039 struct uuid_entry *u; 1040 struct cached_dev *exist_dc, *t; 1041 1042 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1043 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1044 return -ENOENT; 1045 1046 if (dc->disk.c) { 1047 pr_err("Can't attach %s: already attached", 1048 dc->backing_dev_name); 1049 return -EINVAL; 1050 } 1051 1052 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1053 pr_err("Can't attach %s: shutting down", 1054 dc->backing_dev_name); 1055 return -EINVAL; 1056 } 1057 1058 if (dc->sb.block_size < c->sb.block_size) { 1059 /* Will die */ 1060 pr_err("Couldn't attach %s: block size less than set's block size", 1061 dc->backing_dev_name); 1062 return -EINVAL; 1063 } 1064 1065 /* Check whether already attached */ 1066 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1067 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1068 pr_err("Tried to attach %s but duplicate UUID already attached", 1069 dc->backing_dev_name); 1070 1071 return -EINVAL; 1072 } 1073 } 1074 1075 u = uuid_find(c, dc->sb.uuid); 1076 1077 if (u && 1078 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1079 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1080 memcpy(u->uuid, invalid_uuid, 16); 1081 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 1082 u = NULL; 1083 } 1084 1085 if (!u) { 1086 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1087 pr_err("Couldn't find uuid for %s in set", 1088 dc->backing_dev_name); 1089 return -ENOENT; 1090 } 1091 1092 u = uuid_find_empty(c); 1093 if (!u) { 1094 pr_err("Not caching %s, no room for UUID", 1095 dc->backing_dev_name); 1096 return -EINVAL; 1097 } 1098 } 1099 1100 /* Deadlocks since we're called via sysfs... 1101 sysfs_remove_file(&dc->kobj, &sysfs_attach); 1102 */ 1103 1104 if (bch_is_zero(u->uuid, 16)) { 1105 struct closure cl; 1106 closure_init_stack(&cl); 1107 1108 memcpy(u->uuid, dc->sb.uuid, 16); 1109 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1110 u->first_reg = u->last_reg = rtime; 1111 bch_uuid_write(c); 1112 1113 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1114 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1115 1116 bch_write_bdev_super(dc, &cl); 1117 closure_sync(&cl); 1118 } else { 1119 u->last_reg = rtime; 1120 bch_uuid_write(c); 1121 } 1122 1123 bcache_device_attach(&dc->disk, c, u - c->uuids); 1124 list_move(&dc->list, &c->cached_devs); 1125 calc_cached_dev_sectors(c); 1126 1127 smp_wmb(); 1128 /* 1129 * dc->c must be set before dc->count != 0 - paired with the mb in 1130 * cached_dev_get() 1131 */ 1132 refcount_set(&dc->count, 1); 1133 1134 /* Block writeback thread, but spawn it */ 1135 down_write(&dc->writeback_lock); 1136 if (bch_cached_dev_writeback_start(dc)) { 1137 up_write(&dc->writeback_lock); 1138 return -ENOMEM; 1139 } 1140 1141 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1142 bch_sectors_dirty_init(&dc->disk); 1143 atomic_set(&dc->has_dirty, 1); 1144 bch_writeback_queue(dc); 1145 } 1146 1147 bch_cached_dev_run(dc); 1148 bcache_device_link(&dc->disk, c, "bdev"); 1149 atomic_inc(&c->attached_dev_nr); 1150 1151 /* Allow the writeback thread to proceed */ 1152 up_write(&dc->writeback_lock); 1153 1154 pr_info("Caching %s as %s on set %pU", 1155 dc->backing_dev_name, 1156 dc->disk.disk->disk_name, 1157 dc->disk.c->sb.set_uuid); 1158 return 0; 1159 } 1160 1161 void bch_cached_dev_release(struct kobject *kobj) 1162 { 1163 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1164 disk.kobj); 1165 kfree(dc); 1166 module_put(THIS_MODULE); 1167 } 1168 1169 static void cached_dev_free(struct closure *cl) 1170 { 1171 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1172 1173 mutex_lock(&bch_register_lock); 1174 1175 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1176 cancel_writeback_rate_update_dwork(dc); 1177 1178 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1179 kthread_stop(dc->writeback_thread); 1180 if (dc->writeback_write_wq) 1181 destroy_workqueue(dc->writeback_write_wq); 1182 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1183 kthread_stop(dc->status_update_thread); 1184 1185 if (atomic_read(&dc->running)) 1186 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1187 bcache_device_free(&dc->disk); 1188 list_del(&dc->list); 1189 1190 mutex_unlock(&bch_register_lock); 1191 1192 if (!IS_ERR_OR_NULL(dc->bdev)) 1193 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1194 1195 wake_up(&unregister_wait); 1196 1197 kobject_put(&dc->disk.kobj); 1198 } 1199 1200 static void cached_dev_flush(struct closure *cl) 1201 { 1202 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1203 struct bcache_device *d = &dc->disk; 1204 1205 mutex_lock(&bch_register_lock); 1206 bcache_device_unlink(d); 1207 mutex_unlock(&bch_register_lock); 1208 1209 bch_cache_accounting_destroy(&dc->accounting); 1210 kobject_del(&d->kobj); 1211 1212 continue_at(cl, cached_dev_free, system_wq); 1213 } 1214 1215 static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 1216 { 1217 int ret; 1218 struct io *io; 1219 struct request_queue *q = bdev_get_queue(dc->bdev); 1220 1221 __module_get(THIS_MODULE); 1222 INIT_LIST_HEAD(&dc->list); 1223 closure_init(&dc->disk.cl, NULL); 1224 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1225 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1226 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1227 sema_init(&dc->sb_write_mutex, 1); 1228 INIT_LIST_HEAD(&dc->io_lru); 1229 spin_lock_init(&dc->io_lock); 1230 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1231 1232 dc->sequential_cutoff = 4 << 20; 1233 1234 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1235 list_add(&io->lru, &dc->io_lru); 1236 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1237 } 1238 1239 dc->disk.stripe_size = q->limits.io_opt >> 9; 1240 1241 if (dc->disk.stripe_size) 1242 dc->partial_stripes_expensive = 1243 q->limits.raid_partial_stripes_expensive; 1244 1245 ret = bcache_device_init(&dc->disk, block_size, 1246 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1247 if (ret) 1248 return ret; 1249 1250 dc->disk.disk->queue->backing_dev_info->ra_pages = 1251 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1252 q->backing_dev_info->ra_pages); 1253 1254 atomic_set(&dc->io_errors, 0); 1255 dc->io_disable = false; 1256 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1257 /* default to auto */ 1258 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1259 1260 bch_cached_dev_request_init(dc); 1261 bch_cached_dev_writeback_init(dc); 1262 return 0; 1263 } 1264 1265 /* Cached device - bcache superblock */ 1266 1267 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1268 struct block_device *bdev, 1269 struct cached_dev *dc) 1270 { 1271 const char *err = "cannot allocate memory"; 1272 struct cache_set *c; 1273 1274 bdevname(bdev, dc->backing_dev_name); 1275 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1276 dc->bdev = bdev; 1277 dc->bdev->bd_holder = dc; 1278 1279 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1280 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1281 get_page(sb_page); 1282 1283 1284 if (cached_dev_init(dc, sb->block_size << 9)) 1285 goto err; 1286 1287 err = "error creating kobject"; 1288 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1289 "bcache")) 1290 goto err; 1291 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1292 goto err; 1293 1294 pr_info("registered backing device %s", dc->backing_dev_name); 1295 1296 list_add(&dc->list, &uncached_devices); 1297 /* attach to a matched cache set if it exists */ 1298 list_for_each_entry(c, &bch_cache_sets, list) 1299 bch_cached_dev_attach(dc, c, NULL); 1300 1301 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1302 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1303 bch_cached_dev_run(dc); 1304 1305 return; 1306 err: 1307 pr_notice("error %s: %s", dc->backing_dev_name, err); 1308 bcache_device_stop(&dc->disk); 1309 } 1310 1311 /* Flash only volumes */ 1312 1313 void bch_flash_dev_release(struct kobject *kobj) 1314 { 1315 struct bcache_device *d = container_of(kobj, struct bcache_device, 1316 kobj); 1317 kfree(d); 1318 } 1319 1320 static void flash_dev_free(struct closure *cl) 1321 { 1322 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1323 mutex_lock(&bch_register_lock); 1324 atomic_long_sub(bcache_dev_sectors_dirty(d), 1325 &d->c->flash_dev_dirty_sectors); 1326 bcache_device_free(d); 1327 mutex_unlock(&bch_register_lock); 1328 kobject_put(&d->kobj); 1329 } 1330 1331 static void flash_dev_flush(struct closure *cl) 1332 { 1333 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1334 1335 mutex_lock(&bch_register_lock); 1336 bcache_device_unlink(d); 1337 mutex_unlock(&bch_register_lock); 1338 kobject_del(&d->kobj); 1339 continue_at(cl, flash_dev_free, system_wq); 1340 } 1341 1342 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1343 { 1344 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1345 GFP_KERNEL); 1346 if (!d) 1347 return -ENOMEM; 1348 1349 closure_init(&d->cl, NULL); 1350 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1351 1352 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1353 1354 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1355 goto err; 1356 1357 bcache_device_attach(d, c, u - c->uuids); 1358 bch_sectors_dirty_init(d); 1359 bch_flash_dev_request_init(d); 1360 add_disk(d->disk); 1361 1362 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1363 goto err; 1364 1365 bcache_device_link(d, c, "volume"); 1366 1367 return 0; 1368 err: 1369 kobject_put(&d->kobj); 1370 return -ENOMEM; 1371 } 1372 1373 static int flash_devs_run(struct cache_set *c) 1374 { 1375 int ret = 0; 1376 struct uuid_entry *u; 1377 1378 for (u = c->uuids; 1379 u < c->uuids + c->nr_uuids && !ret; 1380 u++) 1381 if (UUID_FLASH_ONLY(u)) 1382 ret = flash_dev_run(c, u); 1383 1384 return ret; 1385 } 1386 1387 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1388 { 1389 struct uuid_entry *u; 1390 1391 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1392 return -EINTR; 1393 1394 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1395 return -EPERM; 1396 1397 u = uuid_find_empty(c); 1398 if (!u) { 1399 pr_err("Can't create volume, no room for UUID"); 1400 return -EINVAL; 1401 } 1402 1403 get_random_bytes(u->uuid, 16); 1404 memset(u->label, 0, 32); 1405 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); 1406 1407 SET_UUID_FLASH_ONLY(u, 1); 1408 u->sectors = size >> 9; 1409 1410 bch_uuid_write(c); 1411 1412 return flash_dev_run(c, u); 1413 } 1414 1415 bool bch_cached_dev_error(struct cached_dev *dc) 1416 { 1417 struct cache_set *c; 1418 1419 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1420 return false; 1421 1422 dc->io_disable = true; 1423 /* make others know io_disable is true earlier */ 1424 smp_mb(); 1425 1426 pr_err("stop %s: too many IO errors on backing device %s\n", 1427 dc->disk.disk->disk_name, dc->backing_dev_name); 1428 1429 /* 1430 * If the cached device is still attached to a cache set, 1431 * even dc->io_disable is true and no more I/O requests 1432 * accepted, cache device internal I/O (writeback scan or 1433 * garbage collection) may still prevent bcache device from 1434 * being stopped. So here CACHE_SET_IO_DISABLE should be 1435 * set to c->flags too, to make the internal I/O to cache 1436 * device rejected and stopped immediately. 1437 * If c is NULL, that means the bcache device is not attached 1438 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. 1439 */ 1440 c = dc->disk.c; 1441 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1442 pr_info("CACHE_SET_IO_DISABLE already set"); 1443 1444 bcache_device_stop(&dc->disk); 1445 return true; 1446 } 1447 1448 /* Cache set */ 1449 1450 __printf(2, 3) 1451 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1452 { 1453 va_list args; 1454 1455 if (c->on_error != ON_ERROR_PANIC && 1456 test_bit(CACHE_SET_STOPPING, &c->flags)) 1457 return false; 1458 1459 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1460 pr_info("CACHE_SET_IO_DISABLE already set"); 1461 1462 /* XXX: we can be called from atomic context 1463 acquire_console_sem(); 1464 */ 1465 1466 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); 1467 1468 va_start(args, fmt); 1469 vprintk(fmt, args); 1470 va_end(args); 1471 1472 printk(", disabling caching\n"); 1473 1474 if (c->on_error == ON_ERROR_PANIC) 1475 panic("panic forced after error\n"); 1476 1477 bch_cache_set_unregister(c); 1478 return true; 1479 } 1480 1481 void bch_cache_set_release(struct kobject *kobj) 1482 { 1483 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1484 kfree(c); 1485 module_put(THIS_MODULE); 1486 } 1487 1488 static void cache_set_free(struct closure *cl) 1489 { 1490 struct cache_set *c = container_of(cl, struct cache_set, cl); 1491 struct cache *ca; 1492 unsigned i; 1493 1494 if (!IS_ERR_OR_NULL(c->debug)) 1495 debugfs_remove(c->debug); 1496 1497 bch_open_buckets_free(c); 1498 bch_btree_cache_free(c); 1499 bch_journal_free(c); 1500 1501 for_each_cache(ca, c, i) 1502 if (ca) { 1503 ca->set = NULL; 1504 c->cache[ca->sb.nr_this_dev] = NULL; 1505 kobject_put(&ca->kobj); 1506 } 1507 1508 bch_bset_sort_state_free(&c->sort); 1509 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1510 1511 if (c->moving_gc_wq) 1512 destroy_workqueue(c->moving_gc_wq); 1513 bioset_exit(&c->bio_split); 1514 mempool_exit(&c->fill_iter); 1515 mempool_exit(&c->bio_meta); 1516 mempool_exit(&c->search); 1517 kfree(c->devices); 1518 1519 mutex_lock(&bch_register_lock); 1520 list_del(&c->list); 1521 mutex_unlock(&bch_register_lock); 1522 1523 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1524 wake_up(&unregister_wait); 1525 1526 closure_debug_destroy(&c->cl); 1527 kobject_put(&c->kobj); 1528 } 1529 1530 static void cache_set_flush(struct closure *cl) 1531 { 1532 struct cache_set *c = container_of(cl, struct cache_set, caching); 1533 struct cache *ca; 1534 struct btree *b; 1535 unsigned i; 1536 1537 bch_cache_accounting_destroy(&c->accounting); 1538 1539 kobject_put(&c->internal); 1540 kobject_del(&c->kobj); 1541 1542 if (c->gc_thread) 1543 kthread_stop(c->gc_thread); 1544 1545 if (!IS_ERR_OR_NULL(c->root)) 1546 list_add(&c->root->list, &c->btree_cache); 1547 1548 /* Should skip this if we're unregistering because of an error */ 1549 list_for_each_entry(b, &c->btree_cache, list) { 1550 mutex_lock(&b->write_lock); 1551 if (btree_node_dirty(b)) 1552 __bch_btree_node_write(b, NULL); 1553 mutex_unlock(&b->write_lock); 1554 } 1555 1556 for_each_cache(ca, c, i) 1557 if (ca->alloc_thread) 1558 kthread_stop(ca->alloc_thread); 1559 1560 if (c->journal.cur) { 1561 cancel_delayed_work_sync(&c->journal.work); 1562 /* flush last journal entry if needed */ 1563 c->journal.work.work.func(&c->journal.work.work); 1564 } 1565 1566 closure_return(cl); 1567 } 1568 1569 /* 1570 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1571 * cache set is unregistering due to too many I/O errors. In this condition, 1572 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1573 * value and whether the broken cache has dirty data: 1574 * 1575 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1576 * BCH_CACHED_STOP_AUTO 0 NO 1577 * BCH_CACHED_STOP_AUTO 1 YES 1578 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1579 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1580 * 1581 * The expected behavior is, if stop_when_cache_set_failed is configured to 1582 * "auto" via sysfs interface, the bcache device will not be stopped if the 1583 * backing device is clean on the broken cache device. 1584 */ 1585 static void conditional_stop_bcache_device(struct cache_set *c, 1586 struct bcache_device *d, 1587 struct cached_dev *dc) 1588 { 1589 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1590 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1591 d->disk->disk_name, c->sb.set_uuid); 1592 bcache_device_stop(d); 1593 } else if (atomic_read(&dc->has_dirty)) { 1594 /* 1595 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1596 * and dc->has_dirty == 1 1597 */ 1598 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1599 d->disk->disk_name); 1600 /* 1601 * There might be a small time gap that cache set is 1602 * released but bcache device is not. Inside this time 1603 * gap, regular I/O requests will directly go into 1604 * backing device as no cache set attached to. This 1605 * behavior may also introduce potential inconsistence 1606 * data in writeback mode while cache is dirty. 1607 * Therefore before calling bcache_device_stop() due 1608 * to a broken cache device, dc->io_disable should be 1609 * explicitly set to true. 1610 */ 1611 dc->io_disable = true; 1612 /* make others know io_disable is true earlier */ 1613 smp_mb(); 1614 bcache_device_stop(d); 1615 } else { 1616 /* 1617 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1618 * and dc->has_dirty == 0 1619 */ 1620 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1621 d->disk->disk_name); 1622 } 1623 } 1624 1625 static void __cache_set_unregister(struct closure *cl) 1626 { 1627 struct cache_set *c = container_of(cl, struct cache_set, caching); 1628 struct cached_dev *dc; 1629 struct bcache_device *d; 1630 size_t i; 1631 1632 mutex_lock(&bch_register_lock); 1633 1634 for (i = 0; i < c->devices_max_used; i++) { 1635 d = c->devices[i]; 1636 if (!d) 1637 continue; 1638 1639 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1640 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1641 dc = container_of(d, struct cached_dev, disk); 1642 bch_cached_dev_detach(dc); 1643 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1644 conditional_stop_bcache_device(c, d, dc); 1645 } else { 1646 bcache_device_stop(d); 1647 } 1648 } 1649 1650 mutex_unlock(&bch_register_lock); 1651 1652 continue_at(cl, cache_set_flush, system_wq); 1653 } 1654 1655 void bch_cache_set_stop(struct cache_set *c) 1656 { 1657 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1658 closure_queue(&c->caching); 1659 } 1660 1661 void bch_cache_set_unregister(struct cache_set *c) 1662 { 1663 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1664 bch_cache_set_stop(c); 1665 } 1666 1667 #define alloc_bucket_pages(gfp, c) \ 1668 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1669 1670 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1671 { 1672 int iter_size; 1673 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1674 if (!c) 1675 return NULL; 1676 1677 __module_get(THIS_MODULE); 1678 closure_init(&c->cl, NULL); 1679 set_closure_fn(&c->cl, cache_set_free, system_wq); 1680 1681 closure_init(&c->caching, &c->cl); 1682 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1683 1684 /* Maybe create continue_at_noreturn() and use it here? */ 1685 closure_set_stopped(&c->cl); 1686 closure_put(&c->cl); 1687 1688 kobject_init(&c->kobj, &bch_cache_set_ktype); 1689 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1690 1691 bch_cache_accounting_init(&c->accounting, &c->cl); 1692 1693 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1694 c->sb.block_size = sb->block_size; 1695 c->sb.bucket_size = sb->bucket_size; 1696 c->sb.nr_in_set = sb->nr_in_set; 1697 c->sb.last_mount = sb->last_mount; 1698 c->bucket_bits = ilog2(sb->bucket_size); 1699 c->block_bits = ilog2(sb->block_size); 1700 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1701 c->devices_max_used = 0; 1702 atomic_set(&c->attached_dev_nr, 0); 1703 c->btree_pages = bucket_pages(c); 1704 if (c->btree_pages > BTREE_MAX_PAGES) 1705 c->btree_pages = max_t(int, c->btree_pages / 4, 1706 BTREE_MAX_PAGES); 1707 1708 sema_init(&c->sb_write_mutex, 1); 1709 mutex_init(&c->bucket_lock); 1710 init_waitqueue_head(&c->btree_cache_wait); 1711 init_waitqueue_head(&c->bucket_wait); 1712 init_waitqueue_head(&c->gc_wait); 1713 sema_init(&c->uuid_write_mutex, 1); 1714 1715 spin_lock_init(&c->btree_gc_time.lock); 1716 spin_lock_init(&c->btree_split_time.lock); 1717 spin_lock_init(&c->btree_read_time.lock); 1718 1719 bch_moving_init_cache_set(c); 1720 1721 INIT_LIST_HEAD(&c->list); 1722 INIT_LIST_HEAD(&c->cached_devs); 1723 INIT_LIST_HEAD(&c->btree_cache); 1724 INIT_LIST_HEAD(&c->btree_cache_freeable); 1725 INIT_LIST_HEAD(&c->btree_cache_freed); 1726 INIT_LIST_HEAD(&c->data_buckets); 1727 1728 iter_size = (sb->bucket_size / sb->block_size + 1) * 1729 sizeof(struct btree_iter_set); 1730 1731 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1732 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1733 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1734 sizeof(struct bbio) + sizeof(struct bio_vec) * 1735 bucket_pages(c)) || 1736 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1737 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1738 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1739 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1740 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1741 WQ_MEM_RECLAIM, 0)) || 1742 bch_journal_alloc(c) || 1743 bch_btree_cache_alloc(c) || 1744 bch_open_buckets_alloc(c) || 1745 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1746 goto err; 1747 1748 c->congested_read_threshold_us = 2000; 1749 c->congested_write_threshold_us = 20000; 1750 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1751 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1752 1753 return c; 1754 err: 1755 bch_cache_set_unregister(c); 1756 return NULL; 1757 } 1758 1759 static void run_cache_set(struct cache_set *c) 1760 { 1761 const char *err = "cannot allocate memory"; 1762 struct cached_dev *dc, *t; 1763 struct cache *ca; 1764 struct closure cl; 1765 unsigned i; 1766 1767 closure_init_stack(&cl); 1768 1769 for_each_cache(ca, c, i) 1770 c->nbuckets += ca->sb.nbuckets; 1771 set_gc_sectors(c); 1772 1773 if (CACHE_SYNC(&c->sb)) { 1774 LIST_HEAD(journal); 1775 struct bkey *k; 1776 struct jset *j; 1777 1778 err = "cannot allocate memory for journal"; 1779 if (bch_journal_read(c, &journal)) 1780 goto err; 1781 1782 pr_debug("btree_journal_read() done"); 1783 1784 err = "no journal entries found"; 1785 if (list_empty(&journal)) 1786 goto err; 1787 1788 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1789 1790 err = "IO error reading priorities"; 1791 for_each_cache(ca, c, i) 1792 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1793 1794 /* 1795 * If prio_read() fails it'll call cache_set_error and we'll 1796 * tear everything down right away, but if we perhaps checked 1797 * sooner we could avoid journal replay. 1798 */ 1799 1800 k = &j->btree_root; 1801 1802 err = "bad btree root"; 1803 if (__bch_btree_ptr_invalid(c, k)) 1804 goto err; 1805 1806 err = "error reading btree root"; 1807 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL); 1808 if (IS_ERR_OR_NULL(c->root)) 1809 goto err; 1810 1811 list_del_init(&c->root->list); 1812 rw_unlock(true, c->root); 1813 1814 err = uuid_read(c, j, &cl); 1815 if (err) 1816 goto err; 1817 1818 err = "error in recovery"; 1819 if (bch_btree_check(c)) 1820 goto err; 1821 1822 bch_journal_mark(c, &journal); 1823 bch_initial_gc_finish(c); 1824 pr_debug("btree_check() done"); 1825 1826 /* 1827 * bcache_journal_next() can't happen sooner, or 1828 * btree_gc_finish() will give spurious errors about last_gc > 1829 * gc_gen - this is a hack but oh well. 1830 */ 1831 bch_journal_next(&c->journal); 1832 1833 err = "error starting allocator thread"; 1834 for_each_cache(ca, c, i) 1835 if (bch_cache_allocator_start(ca)) 1836 goto err; 1837 1838 /* 1839 * First place it's safe to allocate: btree_check() and 1840 * btree_gc_finish() have to run before we have buckets to 1841 * allocate, and bch_bucket_alloc_set() might cause a journal 1842 * entry to be written so bcache_journal_next() has to be called 1843 * first. 1844 * 1845 * If the uuids were in the old format we have to rewrite them 1846 * before the next journal entry is written: 1847 */ 1848 if (j->version < BCACHE_JSET_VERSION_UUID) 1849 __uuid_write(c); 1850 1851 bch_journal_replay(c, &journal); 1852 } else { 1853 pr_notice("invalidating existing data"); 1854 1855 for_each_cache(ca, c, i) { 1856 unsigned j; 1857 1858 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1859 2, SB_JOURNAL_BUCKETS); 1860 1861 for (j = 0; j < ca->sb.keys; j++) 1862 ca->sb.d[j] = ca->sb.first_bucket + j; 1863 } 1864 1865 bch_initial_gc_finish(c); 1866 1867 err = "error starting allocator thread"; 1868 for_each_cache(ca, c, i) 1869 if (bch_cache_allocator_start(ca)) 1870 goto err; 1871 1872 mutex_lock(&c->bucket_lock); 1873 for_each_cache(ca, c, i) 1874 bch_prio_write(ca); 1875 mutex_unlock(&c->bucket_lock); 1876 1877 err = "cannot allocate new UUID bucket"; 1878 if (__uuid_write(c)) 1879 goto err; 1880 1881 err = "cannot allocate new btree root"; 1882 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1883 if (IS_ERR_OR_NULL(c->root)) 1884 goto err; 1885 1886 mutex_lock(&c->root->write_lock); 1887 bkey_copy_key(&c->root->key, &MAX_KEY); 1888 bch_btree_node_write(c->root, &cl); 1889 mutex_unlock(&c->root->write_lock); 1890 1891 bch_btree_set_root(c->root); 1892 rw_unlock(true, c->root); 1893 1894 /* 1895 * We don't want to write the first journal entry until 1896 * everything is set up - fortunately journal entries won't be 1897 * written until the SET_CACHE_SYNC() here: 1898 */ 1899 SET_CACHE_SYNC(&c->sb, true); 1900 1901 bch_journal_next(&c->journal); 1902 bch_journal_meta(c, &cl); 1903 } 1904 1905 err = "error starting gc thread"; 1906 if (bch_gc_thread_start(c)) 1907 goto err; 1908 1909 closure_sync(&cl); 1910 c->sb.last_mount = (u32)ktime_get_real_seconds(); 1911 bcache_write_super(c); 1912 1913 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1914 bch_cached_dev_attach(dc, c, NULL); 1915 1916 flash_devs_run(c); 1917 1918 set_bit(CACHE_SET_RUNNING, &c->flags); 1919 return; 1920 err: 1921 closure_sync(&cl); 1922 /* XXX: test this, it's broken */ 1923 bch_cache_set_error(c, "%s", err); 1924 } 1925 1926 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1927 { 1928 return ca->sb.block_size == c->sb.block_size && 1929 ca->sb.bucket_size == c->sb.bucket_size && 1930 ca->sb.nr_in_set == c->sb.nr_in_set; 1931 } 1932 1933 static const char *register_cache_set(struct cache *ca) 1934 { 1935 char buf[12]; 1936 const char *err = "cannot allocate memory"; 1937 struct cache_set *c; 1938 1939 list_for_each_entry(c, &bch_cache_sets, list) 1940 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1941 if (c->cache[ca->sb.nr_this_dev]) 1942 return "duplicate cache set member"; 1943 1944 if (!can_attach_cache(ca, c)) 1945 return "cache sb does not match set"; 1946 1947 if (!CACHE_SYNC(&ca->sb)) 1948 SET_CACHE_SYNC(&c->sb, false); 1949 1950 goto found; 1951 } 1952 1953 c = bch_cache_set_alloc(&ca->sb); 1954 if (!c) 1955 return err; 1956 1957 err = "error creating kobject"; 1958 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1959 kobject_add(&c->internal, &c->kobj, "internal")) 1960 goto err; 1961 1962 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1963 goto err; 1964 1965 bch_debug_init_cache_set(c); 1966 1967 list_add(&c->list, &bch_cache_sets); 1968 found: 1969 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1970 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1971 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1972 goto err; 1973 1974 if (ca->sb.seq > c->sb.seq) { 1975 c->sb.version = ca->sb.version; 1976 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1977 c->sb.flags = ca->sb.flags; 1978 c->sb.seq = ca->sb.seq; 1979 pr_debug("set version = %llu", c->sb.version); 1980 } 1981 1982 kobject_get(&ca->kobj); 1983 ca->set = c; 1984 ca->set->cache[ca->sb.nr_this_dev] = ca; 1985 c->cache_by_alloc[c->caches_loaded++] = ca; 1986 1987 if (c->caches_loaded == c->sb.nr_in_set) 1988 run_cache_set(c); 1989 1990 return NULL; 1991 err: 1992 bch_cache_set_unregister(c); 1993 return err; 1994 } 1995 1996 /* Cache device */ 1997 1998 void bch_cache_release(struct kobject *kobj) 1999 { 2000 struct cache *ca = container_of(kobj, struct cache, kobj); 2001 unsigned i; 2002 2003 if (ca->set) { 2004 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2005 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2006 } 2007 2008 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2009 kfree(ca->prio_buckets); 2010 vfree(ca->buckets); 2011 2012 free_heap(&ca->heap); 2013 free_fifo(&ca->free_inc); 2014 2015 for (i = 0; i < RESERVE_NR; i++) 2016 free_fifo(&ca->free[i]); 2017 2018 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2019 put_page(bio_first_page_all(&ca->sb_bio)); 2020 2021 if (!IS_ERR_OR_NULL(ca->bdev)) 2022 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2023 2024 kfree(ca); 2025 module_put(THIS_MODULE); 2026 } 2027 2028 static int cache_alloc(struct cache *ca) 2029 { 2030 size_t free; 2031 size_t btree_buckets; 2032 struct bucket *b; 2033 2034 __module_get(THIS_MODULE); 2035 kobject_init(&ca->kobj, &bch_cache_ktype); 2036 2037 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2038 2039 /* 2040 * when ca->sb.njournal_buckets is not zero, journal exists, 2041 * and in bch_journal_replay(), tree node may split, 2042 * so bucket of RESERVE_BTREE type is needed, 2043 * the worst situation is all journal buckets are valid journal, 2044 * and all the keys need to replay, 2045 * so the number of RESERVE_BTREE type buckets should be as much 2046 * as journal buckets 2047 */ 2048 btree_buckets = ca->sb.njournal_buckets ?: 8; 2049 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2050 2051 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) || 2052 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 2053 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 2054 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 2055 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 2056 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 2057 !(ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2058 ca->sb.nbuckets))) || 2059 !(ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2060 prio_buckets(ca), 2), 2061 GFP_KERNEL)) || 2062 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 2063 return -ENOMEM; 2064 2065 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2066 2067 for_each_bucket(b, ca) 2068 atomic_set(&b->pin, 0); 2069 2070 return 0; 2071 } 2072 2073 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2074 struct block_device *bdev, struct cache *ca) 2075 { 2076 const char *err = NULL; /* must be set for any error case */ 2077 int ret = 0; 2078 2079 bdevname(bdev, ca->cache_dev_name); 2080 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2081 ca->bdev = bdev; 2082 ca->bdev->bd_holder = ca; 2083 2084 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2085 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2086 get_page(sb_page); 2087 2088 if (blk_queue_discard(bdev_get_queue(bdev))) 2089 ca->discard = CACHE_DISCARD(&ca->sb); 2090 2091 ret = cache_alloc(ca); 2092 if (ret != 0) { 2093 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2094 if (ret == -ENOMEM) 2095 err = "cache_alloc(): -ENOMEM"; 2096 else 2097 err = "cache_alloc(): unknown error"; 2098 goto err; 2099 } 2100 2101 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) { 2102 err = "error calling kobject_add"; 2103 ret = -ENOMEM; 2104 goto out; 2105 } 2106 2107 mutex_lock(&bch_register_lock); 2108 err = register_cache_set(ca); 2109 mutex_unlock(&bch_register_lock); 2110 2111 if (err) { 2112 ret = -ENODEV; 2113 goto out; 2114 } 2115 2116 pr_info("registered cache device %s", ca->cache_dev_name); 2117 2118 out: 2119 kobject_put(&ca->kobj); 2120 2121 err: 2122 if (err) 2123 pr_notice("error %s: %s", ca->cache_dev_name, err); 2124 2125 return ret; 2126 } 2127 2128 /* Global interfaces/init */ 2129 2130 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, 2131 const char *, size_t); 2132 2133 kobj_attribute_write(register, register_bcache); 2134 kobj_attribute_write(register_quiet, register_bcache); 2135 2136 static bool bch_is_open_backing(struct block_device *bdev) { 2137 struct cache_set *c, *tc; 2138 struct cached_dev *dc, *t; 2139 2140 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2141 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2142 if (dc->bdev == bdev) 2143 return true; 2144 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2145 if (dc->bdev == bdev) 2146 return true; 2147 return false; 2148 } 2149 2150 static bool bch_is_open_cache(struct block_device *bdev) { 2151 struct cache_set *c, *tc; 2152 struct cache *ca; 2153 unsigned i; 2154 2155 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2156 for_each_cache(ca, c, i) 2157 if (ca->bdev == bdev) 2158 return true; 2159 return false; 2160 } 2161 2162 static bool bch_is_open(struct block_device *bdev) { 2163 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2164 } 2165 2166 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2167 const char *buffer, size_t size) 2168 { 2169 ssize_t ret = size; 2170 const char *err = "cannot allocate memory"; 2171 char *path = NULL; 2172 struct cache_sb *sb = NULL; 2173 struct block_device *bdev = NULL; 2174 struct page *sb_page = NULL; 2175 2176 if (!try_module_get(THIS_MODULE)) 2177 return -EBUSY; 2178 2179 path = kstrndup(buffer, size, GFP_KERNEL); 2180 if (!path) 2181 goto err; 2182 2183 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); 2184 if (!sb) 2185 goto err; 2186 2187 err = "failed to open device"; 2188 bdev = blkdev_get_by_path(strim(path), 2189 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2190 sb); 2191 if (IS_ERR(bdev)) { 2192 if (bdev == ERR_PTR(-EBUSY)) { 2193 bdev = lookup_bdev(strim(path)); 2194 mutex_lock(&bch_register_lock); 2195 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2196 err = "device already registered"; 2197 else 2198 err = "device busy"; 2199 mutex_unlock(&bch_register_lock); 2200 if (!IS_ERR(bdev)) 2201 bdput(bdev); 2202 if (attr == &ksysfs_register_quiet) 2203 goto out; 2204 } 2205 goto err; 2206 } 2207 2208 err = "failed to set blocksize"; 2209 if (set_blocksize(bdev, 4096)) 2210 goto err_close; 2211 2212 err = read_super(sb, bdev, &sb_page); 2213 if (err) 2214 goto err_close; 2215 2216 err = "failed to register device"; 2217 if (SB_IS_BDEV(sb)) { 2218 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2219 if (!dc) 2220 goto err_close; 2221 2222 mutex_lock(&bch_register_lock); 2223 register_bdev(sb, sb_page, bdev, dc); 2224 mutex_unlock(&bch_register_lock); 2225 } else { 2226 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2227 if (!ca) 2228 goto err_close; 2229 2230 if (register_cache(sb, sb_page, bdev, ca) != 0) 2231 goto err; 2232 } 2233 out: 2234 if (sb_page) 2235 put_page(sb_page); 2236 kfree(sb); 2237 kfree(path); 2238 module_put(THIS_MODULE); 2239 return ret; 2240 2241 err_close: 2242 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2243 err: 2244 pr_info("error %s: %s", path, err); 2245 ret = -EINVAL; 2246 goto out; 2247 } 2248 2249 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2250 { 2251 if (code == SYS_DOWN || 2252 code == SYS_HALT || 2253 code == SYS_POWER_OFF) { 2254 DEFINE_WAIT(wait); 2255 unsigned long start = jiffies; 2256 bool stopped = false; 2257 2258 struct cache_set *c, *tc; 2259 struct cached_dev *dc, *tdc; 2260 2261 mutex_lock(&bch_register_lock); 2262 2263 if (list_empty(&bch_cache_sets) && 2264 list_empty(&uncached_devices)) 2265 goto out; 2266 2267 pr_info("Stopping all devices:"); 2268 2269 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2270 bch_cache_set_stop(c); 2271 2272 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2273 bcache_device_stop(&dc->disk); 2274 2275 /* What's a condition variable? */ 2276 while (1) { 2277 long timeout = start + 2 * HZ - jiffies; 2278 2279 stopped = list_empty(&bch_cache_sets) && 2280 list_empty(&uncached_devices); 2281 2282 if (timeout < 0 || stopped) 2283 break; 2284 2285 prepare_to_wait(&unregister_wait, &wait, 2286 TASK_UNINTERRUPTIBLE); 2287 2288 mutex_unlock(&bch_register_lock); 2289 schedule_timeout(timeout); 2290 mutex_lock(&bch_register_lock); 2291 } 2292 2293 finish_wait(&unregister_wait, &wait); 2294 2295 if (stopped) 2296 pr_info("All devices stopped"); 2297 else 2298 pr_notice("Timeout waiting for devices to be closed"); 2299 out: 2300 mutex_unlock(&bch_register_lock); 2301 } 2302 2303 return NOTIFY_DONE; 2304 } 2305 2306 static struct notifier_block reboot = { 2307 .notifier_call = bcache_reboot, 2308 .priority = INT_MAX, /* before any real devices */ 2309 }; 2310 2311 static void bcache_exit(void) 2312 { 2313 bch_debug_exit(); 2314 bch_request_exit(); 2315 if (bcache_kobj) 2316 kobject_put(bcache_kobj); 2317 if (bcache_wq) 2318 destroy_workqueue(bcache_wq); 2319 if (bcache_major) 2320 unregister_blkdev(bcache_major, "bcache"); 2321 unregister_reboot_notifier(&reboot); 2322 mutex_destroy(&bch_register_lock); 2323 } 2324 2325 static int __init bcache_init(void) 2326 { 2327 static const struct attribute *files[] = { 2328 &ksysfs_register.attr, 2329 &ksysfs_register_quiet.attr, 2330 NULL 2331 }; 2332 2333 mutex_init(&bch_register_lock); 2334 init_waitqueue_head(&unregister_wait); 2335 register_reboot_notifier(&reboot); 2336 2337 bcache_major = register_blkdev(0, "bcache"); 2338 if (bcache_major < 0) { 2339 unregister_reboot_notifier(&reboot); 2340 mutex_destroy(&bch_register_lock); 2341 return bcache_major; 2342 } 2343 2344 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); 2345 if (!bcache_wq) 2346 goto err; 2347 2348 bcache_kobj = kobject_create_and_add("bcache", fs_kobj); 2349 if (!bcache_kobj) 2350 goto err; 2351 2352 if (bch_request_init() || 2353 sysfs_create_files(bcache_kobj, files)) 2354 goto err; 2355 2356 bch_debug_init(bcache_kobj); 2357 closure_debug_init(); 2358 2359 return 0; 2360 err: 2361 bcache_exit(); 2362 return -ENOMEM; 2363 } 2364 2365 module_exit(bcache_exit); 2366 module_init(bcache_init); 2367