1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * bcache setup/teardown code, and some metadata io - read a superblock and 4 * figure out what to do with it. 5 * 6 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> 7 * Copyright 2012 Google, Inc. 8 */ 9 10 #include "bcache.h" 11 #include "btree.h" 12 #include "debug.h" 13 #include "extents.h" 14 #include "request.h" 15 #include "writeback.h" 16 17 #include <linux/blkdev.h> 18 #include <linux/buffer_head.h> 19 #include <linux/debugfs.h> 20 #include <linux/genhd.h> 21 #include <linux/idr.h> 22 #include <linux/kthread.h> 23 #include <linux/module.h> 24 #include <linux/random.h> 25 #include <linux/reboot.h> 26 #include <linux/sysfs.h> 27 28 MODULE_LICENSE("GPL"); 29 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>"); 30 31 static const char bcache_magic[] = { 32 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca, 33 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 34 }; 35 36 static const char invalid_uuid[] = { 37 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78, 38 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99 39 }; 40 41 static struct kobject *bcache_kobj; 42 struct mutex bch_register_lock; 43 LIST_HEAD(bch_cache_sets); 44 static LIST_HEAD(uncached_devices); 45 46 static int bcache_major; 47 static DEFINE_IDA(bcache_device_idx); 48 static wait_queue_head_t unregister_wait; 49 struct workqueue_struct *bcache_wq; 50 51 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 52 /* limitation of partitions number on single bcache device */ 53 #define BCACHE_MINORS 128 54 /* limitation of bcache devices number on single system */ 55 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 56 57 /* Superblock */ 58 59 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 60 struct page **res) 61 { 62 const char *err; 63 struct cache_sb *s; 64 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 65 unsigned int i; 66 67 if (!bh) 68 return "IO error"; 69 70 s = (struct cache_sb *) bh->b_data; 71 72 sb->offset = le64_to_cpu(s->offset); 73 sb->version = le64_to_cpu(s->version); 74 75 memcpy(sb->magic, s->magic, 16); 76 memcpy(sb->uuid, s->uuid, 16); 77 memcpy(sb->set_uuid, s->set_uuid, 16); 78 memcpy(sb->label, s->label, SB_LABEL_SIZE); 79 80 sb->flags = le64_to_cpu(s->flags); 81 sb->seq = le64_to_cpu(s->seq); 82 sb->last_mount = le32_to_cpu(s->last_mount); 83 sb->first_bucket = le16_to_cpu(s->first_bucket); 84 sb->keys = le16_to_cpu(s->keys); 85 86 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 87 sb->d[i] = le64_to_cpu(s->d[i]); 88 89 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 90 sb->version, sb->flags, sb->seq, sb->keys); 91 92 err = "Not a bcache superblock"; 93 if (sb->offset != SB_SECTOR) 94 goto err; 95 96 if (memcmp(sb->magic, bcache_magic, 16)) 97 goto err; 98 99 err = "Too many journal buckets"; 100 if (sb->keys > SB_JOURNAL_BUCKETS) 101 goto err; 102 103 err = "Bad checksum"; 104 if (s->csum != csum_set(s)) 105 goto err; 106 107 err = "Bad UUID"; 108 if (bch_is_zero(sb->uuid, 16)) 109 goto err; 110 111 sb->block_size = le16_to_cpu(s->block_size); 112 113 err = "Superblock block size smaller than device block size"; 114 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 115 goto err; 116 117 switch (sb->version) { 118 case BCACHE_SB_VERSION_BDEV: 119 sb->data_offset = BDEV_DATA_START_DEFAULT; 120 break; 121 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 122 sb->data_offset = le64_to_cpu(s->data_offset); 123 124 err = "Bad data offset"; 125 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 126 goto err; 127 128 break; 129 case BCACHE_SB_VERSION_CDEV: 130 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 131 sb->nbuckets = le64_to_cpu(s->nbuckets); 132 sb->bucket_size = le16_to_cpu(s->bucket_size); 133 134 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 135 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 136 137 err = "Too many buckets"; 138 if (sb->nbuckets > LONG_MAX) 139 goto err; 140 141 err = "Not enough buckets"; 142 if (sb->nbuckets < 1 << 7) 143 goto err; 144 145 err = "Bad block/bucket size"; 146 if (!is_power_of_2(sb->block_size) || 147 sb->block_size > PAGE_SECTORS || 148 !is_power_of_2(sb->bucket_size) || 149 sb->bucket_size < PAGE_SECTORS) 150 goto err; 151 152 err = "Invalid superblock: device too small"; 153 if (get_capacity(bdev->bd_disk) < 154 sb->bucket_size * sb->nbuckets) 155 goto err; 156 157 err = "Bad UUID"; 158 if (bch_is_zero(sb->set_uuid, 16)) 159 goto err; 160 161 err = "Bad cache device number in set"; 162 if (!sb->nr_in_set || 163 sb->nr_in_set <= sb->nr_this_dev || 164 sb->nr_in_set > MAX_CACHES_PER_SET) 165 goto err; 166 167 err = "Journal buckets not sequential"; 168 for (i = 0; i < sb->keys; i++) 169 if (sb->d[i] != sb->first_bucket + i) 170 goto err; 171 172 err = "Too many journal buckets"; 173 if (sb->first_bucket + sb->keys > sb->nbuckets) 174 goto err; 175 176 err = "Invalid superblock: first bucket comes before end of super"; 177 if (sb->first_bucket * sb->bucket_size < 16) 178 goto err; 179 180 break; 181 default: 182 err = "Unsupported superblock version"; 183 goto err; 184 } 185 186 sb->last_mount = (u32)ktime_get_real_seconds(); 187 err = NULL; 188 189 get_page(bh->b_page); 190 *res = bh->b_page; 191 err: 192 put_bh(bh); 193 return err; 194 } 195 196 static void write_bdev_super_endio(struct bio *bio) 197 { 198 struct cached_dev *dc = bio->bi_private; 199 /* XXX: error checking */ 200 201 closure_put(&dc->sb_write); 202 } 203 204 static void __write_super(struct cache_sb *sb, struct bio *bio) 205 { 206 struct cache_sb *out = page_address(bio_first_page_all(bio)); 207 unsigned int i; 208 209 bio->bi_iter.bi_sector = SB_SECTOR; 210 bio->bi_iter.bi_size = SB_SIZE; 211 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 212 bch_bio_map(bio, NULL); 213 214 out->offset = cpu_to_le64(sb->offset); 215 out->version = cpu_to_le64(sb->version); 216 217 memcpy(out->uuid, sb->uuid, 16); 218 memcpy(out->set_uuid, sb->set_uuid, 16); 219 memcpy(out->label, sb->label, SB_LABEL_SIZE); 220 221 out->flags = cpu_to_le64(sb->flags); 222 out->seq = cpu_to_le64(sb->seq); 223 224 out->last_mount = cpu_to_le32(sb->last_mount); 225 out->first_bucket = cpu_to_le16(sb->first_bucket); 226 out->keys = cpu_to_le16(sb->keys); 227 228 for (i = 0; i < sb->keys; i++) 229 out->d[i] = cpu_to_le64(sb->d[i]); 230 231 out->csum = csum_set(out); 232 233 pr_debug("ver %llu, flags %llu, seq %llu", 234 sb->version, sb->flags, sb->seq); 235 236 submit_bio(bio); 237 } 238 239 static void bch_write_bdev_super_unlock(struct closure *cl) 240 { 241 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 242 243 up(&dc->sb_write_mutex); 244 } 245 246 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 247 { 248 struct closure *cl = &dc->sb_write; 249 struct bio *bio = &dc->sb_bio; 250 251 down(&dc->sb_write_mutex); 252 closure_init(cl, parent); 253 254 bio_reset(bio); 255 bio_set_dev(bio, dc->bdev); 256 bio->bi_end_io = write_bdev_super_endio; 257 bio->bi_private = dc; 258 259 closure_get(cl); 260 /* I/O request sent to backing device */ 261 __write_super(&dc->sb, bio); 262 263 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 264 } 265 266 static void write_super_endio(struct bio *bio) 267 { 268 struct cache *ca = bio->bi_private; 269 270 /* is_read = 0 */ 271 bch_count_io_errors(ca, bio->bi_status, 0, 272 "writing superblock"); 273 closure_put(&ca->set->sb_write); 274 } 275 276 static void bcache_write_super_unlock(struct closure *cl) 277 { 278 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 279 280 up(&c->sb_write_mutex); 281 } 282 283 void bcache_write_super(struct cache_set *c) 284 { 285 struct closure *cl = &c->sb_write; 286 struct cache *ca; 287 unsigned int i; 288 289 down(&c->sb_write_mutex); 290 closure_init(cl, &c->cl); 291 292 c->sb.seq++; 293 294 for_each_cache(ca, c, i) { 295 struct bio *bio = &ca->sb_bio; 296 297 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 298 ca->sb.seq = c->sb.seq; 299 ca->sb.last_mount = c->sb.last_mount; 300 301 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 302 303 bio_reset(bio); 304 bio_set_dev(bio, ca->bdev); 305 bio->bi_end_io = write_super_endio; 306 bio->bi_private = ca; 307 308 closure_get(cl); 309 __write_super(&ca->sb, bio); 310 } 311 312 closure_return_with_destructor(cl, bcache_write_super_unlock); 313 } 314 315 /* UUID io */ 316 317 static void uuid_endio(struct bio *bio) 318 { 319 struct closure *cl = bio->bi_private; 320 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 321 322 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 323 bch_bbio_free(bio, c); 324 closure_put(cl); 325 } 326 327 static void uuid_io_unlock(struct closure *cl) 328 { 329 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 330 331 up(&c->uuid_write_mutex); 332 } 333 334 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 335 struct bkey *k, struct closure *parent) 336 { 337 struct closure *cl = &c->uuid_write; 338 struct uuid_entry *u; 339 unsigned int i; 340 char buf[80]; 341 342 BUG_ON(!parent); 343 down(&c->uuid_write_mutex); 344 closure_init(cl, parent); 345 346 for (i = 0; i < KEY_PTRS(k); i++) { 347 struct bio *bio = bch_bbio_alloc(c); 348 349 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 350 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 351 352 bio->bi_end_io = uuid_endio; 353 bio->bi_private = cl; 354 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 355 bch_bio_map(bio, c->uuids); 356 357 bch_submit_bbio(bio, c, k, i); 358 359 if (op != REQ_OP_WRITE) 360 break; 361 } 362 363 bch_extent_to_text(buf, sizeof(buf), k); 364 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 365 366 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 367 if (!bch_is_zero(u->uuid, 16)) 368 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 369 u - c->uuids, u->uuid, u->label, 370 u->first_reg, u->last_reg, u->invalidated); 371 372 closure_return_with_destructor(cl, uuid_io_unlock); 373 } 374 375 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 376 { 377 struct bkey *k = &j->uuid_bucket; 378 379 if (__bch_btree_ptr_invalid(c, k)) 380 return "bad uuid pointer"; 381 382 bkey_copy(&c->uuid_bucket, k); 383 uuid_io(c, REQ_OP_READ, 0, k, cl); 384 385 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 386 struct uuid_entry_v0 *u0 = (void *) c->uuids; 387 struct uuid_entry *u1 = (void *) c->uuids; 388 int i; 389 390 closure_sync(cl); 391 392 /* 393 * Since the new uuid entry is bigger than the old, we have to 394 * convert starting at the highest memory address and work down 395 * in order to do it in place 396 */ 397 398 for (i = c->nr_uuids - 1; 399 i >= 0; 400 --i) { 401 memcpy(u1[i].uuid, u0[i].uuid, 16); 402 memcpy(u1[i].label, u0[i].label, 32); 403 404 u1[i].first_reg = u0[i].first_reg; 405 u1[i].last_reg = u0[i].last_reg; 406 u1[i].invalidated = u0[i].invalidated; 407 408 u1[i].flags = 0; 409 u1[i].sectors = 0; 410 } 411 } 412 413 return NULL; 414 } 415 416 static int __uuid_write(struct cache_set *c) 417 { 418 BKEY_PADDED(key) k; 419 struct closure cl; 420 421 closure_init_stack(&cl); 422 lockdep_assert_held(&bch_register_lock); 423 424 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 425 return 1; 426 427 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 428 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 429 closure_sync(&cl); 430 431 bkey_copy(&c->uuid_bucket, &k.key); 432 bkey_put(c, &k.key); 433 return 0; 434 } 435 436 int bch_uuid_write(struct cache_set *c) 437 { 438 int ret = __uuid_write(c); 439 440 if (!ret) 441 bch_journal_meta(c, NULL); 442 443 return ret; 444 } 445 446 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 447 { 448 struct uuid_entry *u; 449 450 for (u = c->uuids; 451 u < c->uuids + c->nr_uuids; u++) 452 if (!memcmp(u->uuid, uuid, 16)) 453 return u; 454 455 return NULL; 456 } 457 458 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 459 { 460 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 461 462 return uuid_find(c, zero_uuid); 463 } 464 465 /* 466 * Bucket priorities/gens: 467 * 468 * For each bucket, we store on disk its 469 * 8 bit gen 470 * 16 bit priority 471 * 472 * See alloc.c for an explanation of the gen. The priority is used to implement 473 * lru (and in the future other) cache replacement policies; for most purposes 474 * it's just an opaque integer. 475 * 476 * The gens and the priorities don't have a whole lot to do with each other, and 477 * it's actually the gens that must be written out at specific times - it's no 478 * big deal if the priorities don't get written, if we lose them we just reuse 479 * buckets in suboptimal order. 480 * 481 * On disk they're stored in a packed array, and in as many buckets are required 482 * to fit them all. The buckets we use to store them form a list; the journal 483 * header points to the first bucket, the first bucket points to the second 484 * bucket, et cetera. 485 * 486 * This code is used by the allocation code; periodically (whenever it runs out 487 * of buckets to allocate from) the allocation code will invalidate some 488 * buckets, but it can't use those buckets until their new gens are safely on 489 * disk. 490 */ 491 492 static void prio_endio(struct bio *bio) 493 { 494 struct cache *ca = bio->bi_private; 495 496 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 497 bch_bbio_free(bio, ca->set); 498 closure_put(&ca->prio); 499 } 500 501 static void prio_io(struct cache *ca, uint64_t bucket, int op, 502 unsigned long op_flags) 503 { 504 struct closure *cl = &ca->prio; 505 struct bio *bio = bch_bbio_alloc(ca->set); 506 507 closure_init_stack(cl); 508 509 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 510 bio_set_dev(bio, ca->bdev); 511 bio->bi_iter.bi_size = bucket_bytes(ca); 512 513 bio->bi_end_io = prio_endio; 514 bio->bi_private = ca; 515 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 516 bch_bio_map(bio, ca->disk_buckets); 517 518 closure_bio_submit(ca->set, bio, &ca->prio); 519 closure_sync(cl); 520 } 521 522 void bch_prio_write(struct cache *ca) 523 { 524 int i; 525 struct bucket *b; 526 struct closure cl; 527 528 closure_init_stack(&cl); 529 530 lockdep_assert_held(&ca->set->bucket_lock); 531 532 ca->disk_buckets->seq++; 533 534 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 535 &ca->meta_sectors_written); 536 537 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 538 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 539 540 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 541 long bucket; 542 struct prio_set *p = ca->disk_buckets; 543 struct bucket_disk *d = p->data; 544 struct bucket_disk *end = d + prios_per_bucket(ca); 545 546 for (b = ca->buckets + i * prios_per_bucket(ca); 547 b < ca->buckets + ca->sb.nbuckets && d < end; 548 b++, d++) { 549 d->prio = cpu_to_le16(b->prio); 550 d->gen = b->gen; 551 } 552 553 p->next_bucket = ca->prio_buckets[i + 1]; 554 p->magic = pset_magic(&ca->sb); 555 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 556 557 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 558 BUG_ON(bucket == -1); 559 560 mutex_unlock(&ca->set->bucket_lock); 561 prio_io(ca, bucket, REQ_OP_WRITE, 0); 562 mutex_lock(&ca->set->bucket_lock); 563 564 ca->prio_buckets[i] = bucket; 565 atomic_dec_bug(&ca->buckets[bucket].pin); 566 } 567 568 mutex_unlock(&ca->set->bucket_lock); 569 570 bch_journal_meta(ca->set, &cl); 571 closure_sync(&cl); 572 573 mutex_lock(&ca->set->bucket_lock); 574 575 /* 576 * Don't want the old priorities to get garbage collected until after we 577 * finish writing the new ones, and they're journalled 578 */ 579 for (i = 0; i < prio_buckets(ca); i++) { 580 if (ca->prio_last_buckets[i]) 581 __bch_bucket_free(ca, 582 &ca->buckets[ca->prio_last_buckets[i]]); 583 584 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 585 } 586 } 587 588 static void prio_read(struct cache *ca, uint64_t bucket) 589 { 590 struct prio_set *p = ca->disk_buckets; 591 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 592 struct bucket *b; 593 unsigned int bucket_nr = 0; 594 595 for (b = ca->buckets; 596 b < ca->buckets + ca->sb.nbuckets; 597 b++, d++) { 598 if (d == end) { 599 ca->prio_buckets[bucket_nr] = bucket; 600 ca->prio_last_buckets[bucket_nr] = bucket; 601 bucket_nr++; 602 603 prio_io(ca, bucket, REQ_OP_READ, 0); 604 605 if (p->csum != 606 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 607 pr_warn("bad csum reading priorities"); 608 609 if (p->magic != pset_magic(&ca->sb)) 610 pr_warn("bad magic reading priorities"); 611 612 bucket = p->next_bucket; 613 d = p->data; 614 } 615 616 b->prio = le16_to_cpu(d->prio); 617 b->gen = b->last_gc = d->gen; 618 } 619 } 620 621 /* Bcache device */ 622 623 static int open_dev(struct block_device *b, fmode_t mode) 624 { 625 struct bcache_device *d = b->bd_disk->private_data; 626 627 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 628 return -ENXIO; 629 630 closure_get(&d->cl); 631 return 0; 632 } 633 634 static void release_dev(struct gendisk *b, fmode_t mode) 635 { 636 struct bcache_device *d = b->private_data; 637 638 closure_put(&d->cl); 639 } 640 641 static int ioctl_dev(struct block_device *b, fmode_t mode, 642 unsigned int cmd, unsigned long arg) 643 { 644 struct bcache_device *d = b->bd_disk->private_data; 645 struct cached_dev *dc = container_of(d, struct cached_dev, disk); 646 647 if (dc->io_disable) 648 return -EIO; 649 650 return d->ioctl(d, mode, cmd, arg); 651 } 652 653 static const struct block_device_operations bcache_ops = { 654 .open = open_dev, 655 .release = release_dev, 656 .ioctl = ioctl_dev, 657 .owner = THIS_MODULE, 658 }; 659 660 void bcache_device_stop(struct bcache_device *d) 661 { 662 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 663 closure_queue(&d->cl); 664 } 665 666 static void bcache_device_unlink(struct bcache_device *d) 667 { 668 lockdep_assert_held(&bch_register_lock); 669 670 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 671 unsigned int i; 672 struct cache *ca; 673 674 sysfs_remove_link(&d->c->kobj, d->name); 675 sysfs_remove_link(&d->kobj, "cache"); 676 677 for_each_cache(ca, d->c, i) 678 bd_unlink_disk_holder(ca->bdev, d->disk); 679 } 680 } 681 682 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 683 const char *name) 684 { 685 unsigned int i; 686 struct cache *ca; 687 688 for_each_cache(ca, d->c, i) 689 bd_link_disk_holder(ca->bdev, d->disk); 690 691 snprintf(d->name, BCACHEDEVNAME_SIZE, 692 "%s%u", name, d->id); 693 694 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 695 sysfs_create_link(&c->kobj, &d->kobj, d->name), 696 "Couldn't create device <-> cache set symlinks"); 697 698 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 699 } 700 701 static void bcache_device_detach(struct bcache_device *d) 702 { 703 lockdep_assert_held(&bch_register_lock); 704 705 atomic_dec(&d->c->attached_dev_nr); 706 707 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 708 struct uuid_entry *u = d->c->uuids + d->id; 709 710 SET_UUID_FLASH_ONLY(u, 0); 711 memcpy(u->uuid, invalid_uuid, 16); 712 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 713 bch_uuid_write(d->c); 714 } 715 716 bcache_device_unlink(d); 717 718 d->c->devices[d->id] = NULL; 719 closure_put(&d->c->caching); 720 d->c = NULL; 721 } 722 723 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 724 unsigned int id) 725 { 726 d->id = id; 727 d->c = c; 728 c->devices[id] = d; 729 730 if (id >= c->devices_max_used) 731 c->devices_max_used = id + 1; 732 733 closure_get(&c->caching); 734 } 735 736 static inline int first_minor_to_idx(int first_minor) 737 { 738 return (first_minor/BCACHE_MINORS); 739 } 740 741 static inline int idx_to_first_minor(int idx) 742 { 743 return (idx * BCACHE_MINORS); 744 } 745 746 static void bcache_device_free(struct bcache_device *d) 747 { 748 lockdep_assert_held(&bch_register_lock); 749 750 pr_info("%s stopped", d->disk->disk_name); 751 752 if (d->c) 753 bcache_device_detach(d); 754 if (d->disk && d->disk->flags & GENHD_FL_UP) 755 del_gendisk(d->disk); 756 if (d->disk && d->disk->queue) 757 blk_cleanup_queue(d->disk->queue); 758 if (d->disk) { 759 ida_simple_remove(&bcache_device_idx, 760 first_minor_to_idx(d->disk->first_minor)); 761 put_disk(d->disk); 762 } 763 764 bioset_exit(&d->bio_split); 765 kvfree(d->full_dirty_stripes); 766 kvfree(d->stripe_sectors_dirty); 767 768 closure_debug_destroy(&d->cl); 769 } 770 771 static int bcache_device_init(struct bcache_device *d, unsigned int block_size, 772 sector_t sectors) 773 { 774 struct request_queue *q; 775 const size_t max_stripes = min_t(size_t, INT_MAX, 776 SIZE_MAX / sizeof(atomic_t)); 777 size_t n; 778 int idx; 779 780 if (!d->stripe_size) 781 d->stripe_size = 1 << 31; 782 783 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 784 785 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 786 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 787 (unsigned int)d->nr_stripes); 788 return -ENOMEM; 789 } 790 791 n = d->nr_stripes * sizeof(atomic_t); 792 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 793 if (!d->stripe_sectors_dirty) 794 return -ENOMEM; 795 796 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 797 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 798 if (!d->full_dirty_stripes) 799 return -ENOMEM; 800 801 idx = ida_simple_get(&bcache_device_idx, 0, 802 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 803 if (idx < 0) 804 return idx; 805 806 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 807 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) 808 goto err; 809 810 d->disk = alloc_disk(BCACHE_MINORS); 811 if (!d->disk) 812 goto err; 813 814 set_capacity(d->disk, sectors); 815 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 816 817 d->disk->major = bcache_major; 818 d->disk->first_minor = idx_to_first_minor(idx); 819 d->disk->fops = &bcache_ops; 820 d->disk->private_data = d; 821 822 q = blk_alloc_queue(GFP_KERNEL); 823 if (!q) 824 return -ENOMEM; 825 826 blk_queue_make_request(q, NULL); 827 d->disk->queue = q; 828 q->queuedata = d; 829 q->backing_dev_info->congested_data = d; 830 q->limits.max_hw_sectors = UINT_MAX; 831 q->limits.max_sectors = UINT_MAX; 832 q->limits.max_segment_size = UINT_MAX; 833 q->limits.max_segments = BIO_MAX_PAGES; 834 blk_queue_max_discard_sectors(q, UINT_MAX); 835 q->limits.discard_granularity = 512; 836 q->limits.io_min = block_size; 837 q->limits.logical_block_size = block_size; 838 q->limits.physical_block_size = block_size; 839 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 840 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 841 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 842 843 blk_queue_write_cache(q, true, true); 844 845 return 0; 846 847 err: 848 ida_simple_remove(&bcache_device_idx, idx); 849 return -ENOMEM; 850 851 } 852 853 /* Cached device */ 854 855 static void calc_cached_dev_sectors(struct cache_set *c) 856 { 857 uint64_t sectors = 0; 858 struct cached_dev *dc; 859 860 list_for_each_entry(dc, &c->cached_devs, list) 861 sectors += bdev_sectors(dc->bdev); 862 863 c->cached_dev_sectors = sectors; 864 } 865 866 #define BACKING_DEV_OFFLINE_TIMEOUT 5 867 static int cached_dev_status_update(void *arg) 868 { 869 struct cached_dev *dc = arg; 870 struct request_queue *q; 871 872 /* 873 * If this delayed worker is stopping outside, directly quit here. 874 * dc->io_disable might be set via sysfs interface, so check it 875 * here too. 876 */ 877 while (!kthread_should_stop() && !dc->io_disable) { 878 q = bdev_get_queue(dc->bdev); 879 if (blk_queue_dying(q)) 880 dc->offline_seconds++; 881 else 882 dc->offline_seconds = 0; 883 884 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 885 pr_err("%s: device offline for %d seconds", 886 dc->backing_dev_name, 887 BACKING_DEV_OFFLINE_TIMEOUT); 888 pr_err("%s: disable I/O request due to backing " 889 "device offline", dc->disk.name); 890 dc->io_disable = true; 891 /* let others know earlier that io_disable is true */ 892 smp_mb(); 893 bcache_device_stop(&dc->disk); 894 break; 895 } 896 schedule_timeout_interruptible(HZ); 897 } 898 899 wait_for_kthread_stop(); 900 return 0; 901 } 902 903 904 void bch_cached_dev_run(struct cached_dev *dc) 905 { 906 struct bcache_device *d = &dc->disk; 907 char buf[SB_LABEL_SIZE + 1]; 908 char *env[] = { 909 "DRIVER=bcache", 910 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 911 NULL, 912 NULL, 913 }; 914 915 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 916 buf[SB_LABEL_SIZE] = '\0'; 917 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 918 919 if (atomic_xchg(&dc->running, 1)) { 920 kfree(env[1]); 921 kfree(env[2]); 922 return; 923 } 924 925 if (!d->c && 926 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 927 struct closure cl; 928 929 closure_init_stack(&cl); 930 931 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 932 bch_write_bdev_super(dc, &cl); 933 closure_sync(&cl); 934 } 935 936 add_disk(d->disk); 937 bd_link_disk_holder(dc->bdev, dc->disk.disk); 938 /* 939 * won't show up in the uevent file, use udevadm monitor -e instead 940 * only class / kset properties are persistent 941 */ 942 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 943 kfree(env[1]); 944 kfree(env[2]); 945 946 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 947 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 948 pr_debug("error creating sysfs link"); 949 950 dc->status_update_thread = kthread_run(cached_dev_status_update, 951 dc, "bcache_status_update"); 952 if (IS_ERR(dc->status_update_thread)) { 953 pr_warn("failed to create bcache_status_update kthread, " 954 "continue to run without monitoring backing " 955 "device status"); 956 } 957 } 958 959 /* 960 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 961 * work dc->writeback_rate_update is running. Wait until the routine 962 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 963 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 964 * seconds, give up waiting here and continue to cancel it too. 965 */ 966 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 967 { 968 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 969 970 do { 971 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 972 &dc->disk.flags)) 973 break; 974 time_out--; 975 schedule_timeout_interruptible(1); 976 } while (time_out > 0); 977 978 if (time_out == 0) 979 pr_warn("give up waiting for dc->writeback_write_update to quit"); 980 981 cancel_delayed_work_sync(&dc->writeback_rate_update); 982 } 983 984 static void cached_dev_detach_finish(struct work_struct *w) 985 { 986 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 987 struct closure cl; 988 989 closure_init_stack(&cl); 990 991 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 992 BUG_ON(refcount_read(&dc->count)); 993 994 mutex_lock(&bch_register_lock); 995 996 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 997 cancel_writeback_rate_update_dwork(dc); 998 999 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 1000 kthread_stop(dc->writeback_thread); 1001 dc->writeback_thread = NULL; 1002 } 1003 1004 memset(&dc->sb.set_uuid, 0, 16); 1005 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 1006 1007 bch_write_bdev_super(dc, &cl); 1008 closure_sync(&cl); 1009 1010 bcache_device_detach(&dc->disk); 1011 list_move(&dc->list, &uncached_devices); 1012 1013 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1014 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1015 1016 mutex_unlock(&bch_register_lock); 1017 1018 pr_info("Caching disabled for %s", dc->backing_dev_name); 1019 1020 /* Drop ref we took in cached_dev_detach() */ 1021 closure_put(&dc->disk.cl); 1022 } 1023 1024 void bch_cached_dev_detach(struct cached_dev *dc) 1025 { 1026 lockdep_assert_held(&bch_register_lock); 1027 1028 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1029 return; 1030 1031 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1032 return; 1033 1034 /* 1035 * Block the device from being closed and freed until we're finished 1036 * detaching 1037 */ 1038 closure_get(&dc->disk.cl); 1039 1040 bch_writeback_queue(dc); 1041 1042 cached_dev_put(dc); 1043 } 1044 1045 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1046 uint8_t *set_uuid) 1047 { 1048 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); 1049 struct uuid_entry *u; 1050 struct cached_dev *exist_dc, *t; 1051 1052 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1053 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1054 return -ENOENT; 1055 1056 if (dc->disk.c) { 1057 pr_err("Can't attach %s: already attached", 1058 dc->backing_dev_name); 1059 return -EINVAL; 1060 } 1061 1062 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1063 pr_err("Can't attach %s: shutting down", 1064 dc->backing_dev_name); 1065 return -EINVAL; 1066 } 1067 1068 if (dc->sb.block_size < c->sb.block_size) { 1069 /* Will die */ 1070 pr_err("Couldn't attach %s: block size less than set's block size", 1071 dc->backing_dev_name); 1072 return -EINVAL; 1073 } 1074 1075 /* Check whether already attached */ 1076 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1077 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1078 pr_err("Tried to attach %s but duplicate UUID already attached", 1079 dc->backing_dev_name); 1080 1081 return -EINVAL; 1082 } 1083 } 1084 1085 u = uuid_find(c, dc->sb.uuid); 1086 1087 if (u && 1088 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1089 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1090 memcpy(u->uuid, invalid_uuid, 16); 1091 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 1092 u = NULL; 1093 } 1094 1095 if (!u) { 1096 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1097 pr_err("Couldn't find uuid for %s in set", 1098 dc->backing_dev_name); 1099 return -ENOENT; 1100 } 1101 1102 u = uuid_find_empty(c); 1103 if (!u) { 1104 pr_err("Not caching %s, no room for UUID", 1105 dc->backing_dev_name); 1106 return -EINVAL; 1107 } 1108 } 1109 1110 /* 1111 * Deadlocks since we're called via sysfs... 1112 * sysfs_remove_file(&dc->kobj, &sysfs_attach); 1113 */ 1114 1115 if (bch_is_zero(u->uuid, 16)) { 1116 struct closure cl; 1117 1118 closure_init_stack(&cl); 1119 1120 memcpy(u->uuid, dc->sb.uuid, 16); 1121 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1122 u->first_reg = u->last_reg = rtime; 1123 bch_uuid_write(c); 1124 1125 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1126 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1127 1128 bch_write_bdev_super(dc, &cl); 1129 closure_sync(&cl); 1130 } else { 1131 u->last_reg = rtime; 1132 bch_uuid_write(c); 1133 } 1134 1135 bcache_device_attach(&dc->disk, c, u - c->uuids); 1136 list_move(&dc->list, &c->cached_devs); 1137 calc_cached_dev_sectors(c); 1138 1139 /* 1140 * dc->c must be set before dc->count != 0 - paired with the mb in 1141 * cached_dev_get() 1142 */ 1143 smp_wmb(); 1144 refcount_set(&dc->count, 1); 1145 1146 /* Block writeback thread, but spawn it */ 1147 down_write(&dc->writeback_lock); 1148 if (bch_cached_dev_writeback_start(dc)) { 1149 up_write(&dc->writeback_lock); 1150 return -ENOMEM; 1151 } 1152 1153 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1154 bch_sectors_dirty_init(&dc->disk); 1155 atomic_set(&dc->has_dirty, 1); 1156 bch_writeback_queue(dc); 1157 } 1158 1159 bch_cached_dev_run(dc); 1160 bcache_device_link(&dc->disk, c, "bdev"); 1161 atomic_inc(&c->attached_dev_nr); 1162 1163 /* Allow the writeback thread to proceed */ 1164 up_write(&dc->writeback_lock); 1165 1166 pr_info("Caching %s as %s on set %pU", 1167 dc->backing_dev_name, 1168 dc->disk.disk->disk_name, 1169 dc->disk.c->sb.set_uuid); 1170 return 0; 1171 } 1172 1173 void bch_cached_dev_release(struct kobject *kobj) 1174 { 1175 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1176 disk.kobj); 1177 kfree(dc); 1178 module_put(THIS_MODULE); 1179 } 1180 1181 static void cached_dev_free(struct closure *cl) 1182 { 1183 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1184 1185 mutex_lock(&bch_register_lock); 1186 1187 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1188 cancel_writeback_rate_update_dwork(dc); 1189 1190 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1191 kthread_stop(dc->writeback_thread); 1192 if (dc->writeback_write_wq) 1193 destroy_workqueue(dc->writeback_write_wq); 1194 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1195 kthread_stop(dc->status_update_thread); 1196 1197 if (atomic_read(&dc->running)) 1198 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1199 bcache_device_free(&dc->disk); 1200 list_del(&dc->list); 1201 1202 mutex_unlock(&bch_register_lock); 1203 1204 if (!IS_ERR_OR_NULL(dc->bdev)) 1205 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1206 1207 wake_up(&unregister_wait); 1208 1209 kobject_put(&dc->disk.kobj); 1210 } 1211 1212 static void cached_dev_flush(struct closure *cl) 1213 { 1214 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1215 struct bcache_device *d = &dc->disk; 1216 1217 mutex_lock(&bch_register_lock); 1218 bcache_device_unlink(d); 1219 mutex_unlock(&bch_register_lock); 1220 1221 bch_cache_accounting_destroy(&dc->accounting); 1222 kobject_del(&d->kobj); 1223 1224 continue_at(cl, cached_dev_free, system_wq); 1225 } 1226 1227 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size) 1228 { 1229 int ret; 1230 struct io *io; 1231 struct request_queue *q = bdev_get_queue(dc->bdev); 1232 1233 __module_get(THIS_MODULE); 1234 INIT_LIST_HEAD(&dc->list); 1235 closure_init(&dc->disk.cl, NULL); 1236 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1237 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1238 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1239 sema_init(&dc->sb_write_mutex, 1); 1240 INIT_LIST_HEAD(&dc->io_lru); 1241 spin_lock_init(&dc->io_lock); 1242 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1243 1244 dc->sequential_cutoff = 4 << 20; 1245 1246 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1247 list_add(&io->lru, &dc->io_lru); 1248 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1249 } 1250 1251 dc->disk.stripe_size = q->limits.io_opt >> 9; 1252 1253 if (dc->disk.stripe_size) 1254 dc->partial_stripes_expensive = 1255 q->limits.raid_partial_stripes_expensive; 1256 1257 ret = bcache_device_init(&dc->disk, block_size, 1258 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1259 if (ret) 1260 return ret; 1261 1262 dc->disk.disk->queue->backing_dev_info->ra_pages = 1263 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1264 q->backing_dev_info->ra_pages); 1265 1266 atomic_set(&dc->io_errors, 0); 1267 dc->io_disable = false; 1268 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1269 /* default to auto */ 1270 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1271 1272 bch_cached_dev_request_init(dc); 1273 bch_cached_dev_writeback_init(dc); 1274 return 0; 1275 } 1276 1277 /* Cached device - bcache superblock */ 1278 1279 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1280 struct block_device *bdev, 1281 struct cached_dev *dc) 1282 { 1283 const char *err = "cannot allocate memory"; 1284 struct cache_set *c; 1285 1286 bdevname(bdev, dc->backing_dev_name); 1287 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1288 dc->bdev = bdev; 1289 dc->bdev->bd_holder = dc; 1290 1291 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1292 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1293 get_page(sb_page); 1294 1295 1296 if (cached_dev_init(dc, sb->block_size << 9)) 1297 goto err; 1298 1299 err = "error creating kobject"; 1300 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1301 "bcache")) 1302 goto err; 1303 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1304 goto err; 1305 1306 pr_info("registered backing device %s", dc->backing_dev_name); 1307 1308 list_add(&dc->list, &uncached_devices); 1309 /* attach to a matched cache set if it exists */ 1310 list_for_each_entry(c, &bch_cache_sets, list) 1311 bch_cached_dev_attach(dc, c, NULL); 1312 1313 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1314 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1315 bch_cached_dev_run(dc); 1316 1317 return; 1318 err: 1319 pr_notice("error %s: %s", dc->backing_dev_name, err); 1320 bcache_device_stop(&dc->disk); 1321 } 1322 1323 /* Flash only volumes */ 1324 1325 void bch_flash_dev_release(struct kobject *kobj) 1326 { 1327 struct bcache_device *d = container_of(kobj, struct bcache_device, 1328 kobj); 1329 kfree(d); 1330 } 1331 1332 static void flash_dev_free(struct closure *cl) 1333 { 1334 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1335 1336 mutex_lock(&bch_register_lock); 1337 atomic_long_sub(bcache_dev_sectors_dirty(d), 1338 &d->c->flash_dev_dirty_sectors); 1339 bcache_device_free(d); 1340 mutex_unlock(&bch_register_lock); 1341 kobject_put(&d->kobj); 1342 } 1343 1344 static void flash_dev_flush(struct closure *cl) 1345 { 1346 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1347 1348 mutex_lock(&bch_register_lock); 1349 bcache_device_unlink(d); 1350 mutex_unlock(&bch_register_lock); 1351 kobject_del(&d->kobj); 1352 continue_at(cl, flash_dev_free, system_wq); 1353 } 1354 1355 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1356 { 1357 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1358 GFP_KERNEL); 1359 if (!d) 1360 return -ENOMEM; 1361 1362 closure_init(&d->cl, NULL); 1363 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1364 1365 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1366 1367 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1368 goto err; 1369 1370 bcache_device_attach(d, c, u - c->uuids); 1371 bch_sectors_dirty_init(d); 1372 bch_flash_dev_request_init(d); 1373 add_disk(d->disk); 1374 1375 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1376 goto err; 1377 1378 bcache_device_link(d, c, "volume"); 1379 1380 return 0; 1381 err: 1382 kobject_put(&d->kobj); 1383 return -ENOMEM; 1384 } 1385 1386 static int flash_devs_run(struct cache_set *c) 1387 { 1388 int ret = 0; 1389 struct uuid_entry *u; 1390 1391 for (u = c->uuids; 1392 u < c->uuids + c->nr_uuids && !ret; 1393 u++) 1394 if (UUID_FLASH_ONLY(u)) 1395 ret = flash_dev_run(c, u); 1396 1397 return ret; 1398 } 1399 1400 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1401 { 1402 struct uuid_entry *u; 1403 1404 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1405 return -EINTR; 1406 1407 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1408 return -EPERM; 1409 1410 u = uuid_find_empty(c); 1411 if (!u) { 1412 pr_err("Can't create volume, no room for UUID"); 1413 return -EINVAL; 1414 } 1415 1416 get_random_bytes(u->uuid, 16); 1417 memset(u->label, 0, 32); 1418 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); 1419 1420 SET_UUID_FLASH_ONLY(u, 1); 1421 u->sectors = size >> 9; 1422 1423 bch_uuid_write(c); 1424 1425 return flash_dev_run(c, u); 1426 } 1427 1428 bool bch_cached_dev_error(struct cached_dev *dc) 1429 { 1430 struct cache_set *c; 1431 1432 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1433 return false; 1434 1435 dc->io_disable = true; 1436 /* make others know io_disable is true earlier */ 1437 smp_mb(); 1438 1439 pr_err("stop %s: too many IO errors on backing device %s\n", 1440 dc->disk.disk->disk_name, dc->backing_dev_name); 1441 1442 /* 1443 * If the cached device is still attached to a cache set, 1444 * even dc->io_disable is true and no more I/O requests 1445 * accepted, cache device internal I/O (writeback scan or 1446 * garbage collection) may still prevent bcache device from 1447 * being stopped. So here CACHE_SET_IO_DISABLE should be 1448 * set to c->flags too, to make the internal I/O to cache 1449 * device rejected and stopped immediately. 1450 * If c is NULL, that means the bcache device is not attached 1451 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. 1452 */ 1453 c = dc->disk.c; 1454 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1455 pr_info("CACHE_SET_IO_DISABLE already set"); 1456 1457 bcache_device_stop(&dc->disk); 1458 return true; 1459 } 1460 1461 /* Cache set */ 1462 1463 __printf(2, 3) 1464 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1465 { 1466 va_list args; 1467 1468 if (c->on_error != ON_ERROR_PANIC && 1469 test_bit(CACHE_SET_STOPPING, &c->flags)) 1470 return false; 1471 1472 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1473 pr_info("CACHE_SET_IO_DISABLE already set"); 1474 1475 /* 1476 * XXX: we can be called from atomic context 1477 * acquire_console_sem(); 1478 */ 1479 1480 pr_err("bcache: error on %pU: ", c->sb.set_uuid); 1481 1482 va_start(args, fmt); 1483 vprintk(fmt, args); 1484 va_end(args); 1485 1486 pr_err(", disabling caching\n"); 1487 1488 if (c->on_error == ON_ERROR_PANIC) 1489 panic("panic forced after error\n"); 1490 1491 bch_cache_set_unregister(c); 1492 return true; 1493 } 1494 1495 void bch_cache_set_release(struct kobject *kobj) 1496 { 1497 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1498 1499 kfree(c); 1500 module_put(THIS_MODULE); 1501 } 1502 1503 static void cache_set_free(struct closure *cl) 1504 { 1505 struct cache_set *c = container_of(cl, struct cache_set, cl); 1506 struct cache *ca; 1507 unsigned int i; 1508 1509 if (!IS_ERR_OR_NULL(c->debug)) 1510 debugfs_remove(c->debug); 1511 1512 bch_open_buckets_free(c); 1513 bch_btree_cache_free(c); 1514 bch_journal_free(c); 1515 1516 for_each_cache(ca, c, i) 1517 if (ca) { 1518 ca->set = NULL; 1519 c->cache[ca->sb.nr_this_dev] = NULL; 1520 kobject_put(&ca->kobj); 1521 } 1522 1523 bch_bset_sort_state_free(&c->sort); 1524 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1525 1526 if (c->moving_gc_wq) 1527 destroy_workqueue(c->moving_gc_wq); 1528 bioset_exit(&c->bio_split); 1529 mempool_exit(&c->fill_iter); 1530 mempool_exit(&c->bio_meta); 1531 mempool_exit(&c->search); 1532 kfree(c->devices); 1533 1534 mutex_lock(&bch_register_lock); 1535 list_del(&c->list); 1536 mutex_unlock(&bch_register_lock); 1537 1538 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1539 wake_up(&unregister_wait); 1540 1541 closure_debug_destroy(&c->cl); 1542 kobject_put(&c->kobj); 1543 } 1544 1545 static void cache_set_flush(struct closure *cl) 1546 { 1547 struct cache_set *c = container_of(cl, struct cache_set, caching); 1548 struct cache *ca; 1549 struct btree *b; 1550 unsigned int i; 1551 1552 bch_cache_accounting_destroy(&c->accounting); 1553 1554 kobject_put(&c->internal); 1555 kobject_del(&c->kobj); 1556 1557 if (c->gc_thread) 1558 kthread_stop(c->gc_thread); 1559 1560 if (!IS_ERR_OR_NULL(c->root)) 1561 list_add(&c->root->list, &c->btree_cache); 1562 1563 /* Should skip this if we're unregistering because of an error */ 1564 list_for_each_entry(b, &c->btree_cache, list) { 1565 mutex_lock(&b->write_lock); 1566 if (btree_node_dirty(b)) 1567 __bch_btree_node_write(b, NULL); 1568 mutex_unlock(&b->write_lock); 1569 } 1570 1571 for_each_cache(ca, c, i) 1572 if (ca->alloc_thread) 1573 kthread_stop(ca->alloc_thread); 1574 1575 if (c->journal.cur) { 1576 cancel_delayed_work_sync(&c->journal.work); 1577 /* flush last journal entry if needed */ 1578 c->journal.work.work.func(&c->journal.work.work); 1579 } 1580 1581 closure_return(cl); 1582 } 1583 1584 /* 1585 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1586 * cache set is unregistering due to too many I/O errors. In this condition, 1587 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1588 * value and whether the broken cache has dirty data: 1589 * 1590 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1591 * BCH_CACHED_STOP_AUTO 0 NO 1592 * BCH_CACHED_STOP_AUTO 1 YES 1593 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1594 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1595 * 1596 * The expected behavior is, if stop_when_cache_set_failed is configured to 1597 * "auto" via sysfs interface, the bcache device will not be stopped if the 1598 * backing device is clean on the broken cache device. 1599 */ 1600 static void conditional_stop_bcache_device(struct cache_set *c, 1601 struct bcache_device *d, 1602 struct cached_dev *dc) 1603 { 1604 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1605 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1606 d->disk->disk_name, c->sb.set_uuid); 1607 bcache_device_stop(d); 1608 } else if (atomic_read(&dc->has_dirty)) { 1609 /* 1610 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1611 * and dc->has_dirty == 1 1612 */ 1613 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1614 d->disk->disk_name); 1615 /* 1616 * There might be a small time gap that cache set is 1617 * released but bcache device is not. Inside this time 1618 * gap, regular I/O requests will directly go into 1619 * backing device as no cache set attached to. This 1620 * behavior may also introduce potential inconsistence 1621 * data in writeback mode while cache is dirty. 1622 * Therefore before calling bcache_device_stop() due 1623 * to a broken cache device, dc->io_disable should be 1624 * explicitly set to true. 1625 */ 1626 dc->io_disable = true; 1627 /* make others know io_disable is true earlier */ 1628 smp_mb(); 1629 bcache_device_stop(d); 1630 } else { 1631 /* 1632 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1633 * and dc->has_dirty == 0 1634 */ 1635 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1636 d->disk->disk_name); 1637 } 1638 } 1639 1640 static void __cache_set_unregister(struct closure *cl) 1641 { 1642 struct cache_set *c = container_of(cl, struct cache_set, caching); 1643 struct cached_dev *dc; 1644 struct bcache_device *d; 1645 size_t i; 1646 1647 mutex_lock(&bch_register_lock); 1648 1649 for (i = 0; i < c->devices_max_used; i++) { 1650 d = c->devices[i]; 1651 if (!d) 1652 continue; 1653 1654 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1655 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1656 dc = container_of(d, struct cached_dev, disk); 1657 bch_cached_dev_detach(dc); 1658 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1659 conditional_stop_bcache_device(c, d, dc); 1660 } else { 1661 bcache_device_stop(d); 1662 } 1663 } 1664 1665 mutex_unlock(&bch_register_lock); 1666 1667 continue_at(cl, cache_set_flush, system_wq); 1668 } 1669 1670 void bch_cache_set_stop(struct cache_set *c) 1671 { 1672 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1673 closure_queue(&c->caching); 1674 } 1675 1676 void bch_cache_set_unregister(struct cache_set *c) 1677 { 1678 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1679 bch_cache_set_stop(c); 1680 } 1681 1682 #define alloc_bucket_pages(gfp, c) \ 1683 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1684 1685 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1686 { 1687 int iter_size; 1688 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1689 1690 if (!c) 1691 return NULL; 1692 1693 __module_get(THIS_MODULE); 1694 closure_init(&c->cl, NULL); 1695 set_closure_fn(&c->cl, cache_set_free, system_wq); 1696 1697 closure_init(&c->caching, &c->cl); 1698 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1699 1700 /* Maybe create continue_at_noreturn() and use it here? */ 1701 closure_set_stopped(&c->cl); 1702 closure_put(&c->cl); 1703 1704 kobject_init(&c->kobj, &bch_cache_set_ktype); 1705 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1706 1707 bch_cache_accounting_init(&c->accounting, &c->cl); 1708 1709 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1710 c->sb.block_size = sb->block_size; 1711 c->sb.bucket_size = sb->bucket_size; 1712 c->sb.nr_in_set = sb->nr_in_set; 1713 c->sb.last_mount = sb->last_mount; 1714 c->bucket_bits = ilog2(sb->bucket_size); 1715 c->block_bits = ilog2(sb->block_size); 1716 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1717 c->devices_max_used = 0; 1718 atomic_set(&c->attached_dev_nr, 0); 1719 c->btree_pages = bucket_pages(c); 1720 if (c->btree_pages > BTREE_MAX_PAGES) 1721 c->btree_pages = max_t(int, c->btree_pages / 4, 1722 BTREE_MAX_PAGES); 1723 1724 sema_init(&c->sb_write_mutex, 1); 1725 mutex_init(&c->bucket_lock); 1726 init_waitqueue_head(&c->btree_cache_wait); 1727 init_waitqueue_head(&c->bucket_wait); 1728 init_waitqueue_head(&c->gc_wait); 1729 sema_init(&c->uuid_write_mutex, 1); 1730 1731 spin_lock_init(&c->btree_gc_time.lock); 1732 spin_lock_init(&c->btree_split_time.lock); 1733 spin_lock_init(&c->btree_read_time.lock); 1734 1735 bch_moving_init_cache_set(c); 1736 1737 INIT_LIST_HEAD(&c->list); 1738 INIT_LIST_HEAD(&c->cached_devs); 1739 INIT_LIST_HEAD(&c->btree_cache); 1740 INIT_LIST_HEAD(&c->btree_cache_freeable); 1741 INIT_LIST_HEAD(&c->btree_cache_freed); 1742 INIT_LIST_HEAD(&c->data_buckets); 1743 1744 iter_size = (sb->bucket_size / sb->block_size + 1) * 1745 sizeof(struct btree_iter_set); 1746 1747 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1748 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1749 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1750 sizeof(struct bbio) + sizeof(struct bio_vec) * 1751 bucket_pages(c)) || 1752 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1753 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1754 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1755 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1756 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1757 WQ_MEM_RECLAIM, 0)) || 1758 bch_journal_alloc(c) || 1759 bch_btree_cache_alloc(c) || 1760 bch_open_buckets_alloc(c) || 1761 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1762 goto err; 1763 1764 c->congested_read_threshold_us = 2000; 1765 c->congested_write_threshold_us = 20000; 1766 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1767 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1768 1769 return c; 1770 err: 1771 bch_cache_set_unregister(c); 1772 return NULL; 1773 } 1774 1775 static void run_cache_set(struct cache_set *c) 1776 { 1777 const char *err = "cannot allocate memory"; 1778 struct cached_dev *dc, *t; 1779 struct cache *ca; 1780 struct closure cl; 1781 unsigned int i; 1782 1783 closure_init_stack(&cl); 1784 1785 for_each_cache(ca, c, i) 1786 c->nbuckets += ca->sb.nbuckets; 1787 set_gc_sectors(c); 1788 1789 if (CACHE_SYNC(&c->sb)) { 1790 LIST_HEAD(journal); 1791 struct bkey *k; 1792 struct jset *j; 1793 1794 err = "cannot allocate memory for journal"; 1795 if (bch_journal_read(c, &journal)) 1796 goto err; 1797 1798 pr_debug("btree_journal_read() done"); 1799 1800 err = "no journal entries found"; 1801 if (list_empty(&journal)) 1802 goto err; 1803 1804 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1805 1806 err = "IO error reading priorities"; 1807 for_each_cache(ca, c, i) 1808 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1809 1810 /* 1811 * If prio_read() fails it'll call cache_set_error and we'll 1812 * tear everything down right away, but if we perhaps checked 1813 * sooner we could avoid journal replay. 1814 */ 1815 1816 k = &j->btree_root; 1817 1818 err = "bad btree root"; 1819 if (__bch_btree_ptr_invalid(c, k)) 1820 goto err; 1821 1822 err = "error reading btree root"; 1823 c->root = bch_btree_node_get(c, NULL, k, 1824 j->btree_level, 1825 true, NULL); 1826 if (IS_ERR_OR_NULL(c->root)) 1827 goto err; 1828 1829 list_del_init(&c->root->list); 1830 rw_unlock(true, c->root); 1831 1832 err = uuid_read(c, j, &cl); 1833 if (err) 1834 goto err; 1835 1836 err = "error in recovery"; 1837 if (bch_btree_check(c)) 1838 goto err; 1839 1840 bch_journal_mark(c, &journal); 1841 bch_initial_gc_finish(c); 1842 pr_debug("btree_check() done"); 1843 1844 /* 1845 * bcache_journal_next() can't happen sooner, or 1846 * btree_gc_finish() will give spurious errors about last_gc > 1847 * gc_gen - this is a hack but oh well. 1848 */ 1849 bch_journal_next(&c->journal); 1850 1851 err = "error starting allocator thread"; 1852 for_each_cache(ca, c, i) 1853 if (bch_cache_allocator_start(ca)) 1854 goto err; 1855 1856 /* 1857 * First place it's safe to allocate: btree_check() and 1858 * btree_gc_finish() have to run before we have buckets to 1859 * allocate, and bch_bucket_alloc_set() might cause a journal 1860 * entry to be written so bcache_journal_next() has to be called 1861 * first. 1862 * 1863 * If the uuids were in the old format we have to rewrite them 1864 * before the next journal entry is written: 1865 */ 1866 if (j->version < BCACHE_JSET_VERSION_UUID) 1867 __uuid_write(c); 1868 1869 bch_journal_replay(c, &journal); 1870 } else { 1871 pr_notice("invalidating existing data"); 1872 1873 for_each_cache(ca, c, i) { 1874 unsigned int j; 1875 1876 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1877 2, SB_JOURNAL_BUCKETS); 1878 1879 for (j = 0; j < ca->sb.keys; j++) 1880 ca->sb.d[j] = ca->sb.first_bucket + j; 1881 } 1882 1883 bch_initial_gc_finish(c); 1884 1885 err = "error starting allocator thread"; 1886 for_each_cache(ca, c, i) 1887 if (bch_cache_allocator_start(ca)) 1888 goto err; 1889 1890 mutex_lock(&c->bucket_lock); 1891 for_each_cache(ca, c, i) 1892 bch_prio_write(ca); 1893 mutex_unlock(&c->bucket_lock); 1894 1895 err = "cannot allocate new UUID bucket"; 1896 if (__uuid_write(c)) 1897 goto err; 1898 1899 err = "cannot allocate new btree root"; 1900 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1901 if (IS_ERR_OR_NULL(c->root)) 1902 goto err; 1903 1904 mutex_lock(&c->root->write_lock); 1905 bkey_copy_key(&c->root->key, &MAX_KEY); 1906 bch_btree_node_write(c->root, &cl); 1907 mutex_unlock(&c->root->write_lock); 1908 1909 bch_btree_set_root(c->root); 1910 rw_unlock(true, c->root); 1911 1912 /* 1913 * We don't want to write the first journal entry until 1914 * everything is set up - fortunately journal entries won't be 1915 * written until the SET_CACHE_SYNC() here: 1916 */ 1917 SET_CACHE_SYNC(&c->sb, true); 1918 1919 bch_journal_next(&c->journal); 1920 bch_journal_meta(c, &cl); 1921 } 1922 1923 err = "error starting gc thread"; 1924 if (bch_gc_thread_start(c)) 1925 goto err; 1926 1927 closure_sync(&cl); 1928 c->sb.last_mount = (u32)ktime_get_real_seconds(); 1929 bcache_write_super(c); 1930 1931 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1932 bch_cached_dev_attach(dc, c, NULL); 1933 1934 flash_devs_run(c); 1935 1936 set_bit(CACHE_SET_RUNNING, &c->flags); 1937 return; 1938 err: 1939 closure_sync(&cl); 1940 /* XXX: test this, it's broken */ 1941 bch_cache_set_error(c, "%s", err); 1942 } 1943 1944 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1945 { 1946 return ca->sb.block_size == c->sb.block_size && 1947 ca->sb.bucket_size == c->sb.bucket_size && 1948 ca->sb.nr_in_set == c->sb.nr_in_set; 1949 } 1950 1951 static const char *register_cache_set(struct cache *ca) 1952 { 1953 char buf[12]; 1954 const char *err = "cannot allocate memory"; 1955 struct cache_set *c; 1956 1957 list_for_each_entry(c, &bch_cache_sets, list) 1958 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1959 if (c->cache[ca->sb.nr_this_dev]) 1960 return "duplicate cache set member"; 1961 1962 if (!can_attach_cache(ca, c)) 1963 return "cache sb does not match set"; 1964 1965 if (!CACHE_SYNC(&ca->sb)) 1966 SET_CACHE_SYNC(&c->sb, false); 1967 1968 goto found; 1969 } 1970 1971 c = bch_cache_set_alloc(&ca->sb); 1972 if (!c) 1973 return err; 1974 1975 err = "error creating kobject"; 1976 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1977 kobject_add(&c->internal, &c->kobj, "internal")) 1978 goto err; 1979 1980 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1981 goto err; 1982 1983 bch_debug_init_cache_set(c); 1984 1985 list_add(&c->list, &bch_cache_sets); 1986 found: 1987 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1988 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1989 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1990 goto err; 1991 1992 if (ca->sb.seq > c->sb.seq) { 1993 c->sb.version = ca->sb.version; 1994 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1995 c->sb.flags = ca->sb.flags; 1996 c->sb.seq = ca->sb.seq; 1997 pr_debug("set version = %llu", c->sb.version); 1998 } 1999 2000 kobject_get(&ca->kobj); 2001 ca->set = c; 2002 ca->set->cache[ca->sb.nr_this_dev] = ca; 2003 c->cache_by_alloc[c->caches_loaded++] = ca; 2004 2005 if (c->caches_loaded == c->sb.nr_in_set) 2006 run_cache_set(c); 2007 2008 return NULL; 2009 err: 2010 bch_cache_set_unregister(c); 2011 return err; 2012 } 2013 2014 /* Cache device */ 2015 2016 void bch_cache_release(struct kobject *kobj) 2017 { 2018 struct cache *ca = container_of(kobj, struct cache, kobj); 2019 unsigned int i; 2020 2021 if (ca->set) { 2022 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2023 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2024 } 2025 2026 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2027 kfree(ca->prio_buckets); 2028 vfree(ca->buckets); 2029 2030 free_heap(&ca->heap); 2031 free_fifo(&ca->free_inc); 2032 2033 for (i = 0; i < RESERVE_NR; i++) 2034 free_fifo(&ca->free[i]); 2035 2036 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2037 put_page(bio_first_page_all(&ca->sb_bio)); 2038 2039 if (!IS_ERR_OR_NULL(ca->bdev)) 2040 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2041 2042 kfree(ca); 2043 module_put(THIS_MODULE); 2044 } 2045 2046 static int cache_alloc(struct cache *ca) 2047 { 2048 size_t free; 2049 size_t btree_buckets; 2050 struct bucket *b; 2051 2052 __module_get(THIS_MODULE); 2053 kobject_init(&ca->kobj, &bch_cache_ktype); 2054 2055 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2056 2057 /* 2058 * when ca->sb.njournal_buckets is not zero, journal exists, 2059 * and in bch_journal_replay(), tree node may split, 2060 * so bucket of RESERVE_BTREE type is needed, 2061 * the worst situation is all journal buckets are valid journal, 2062 * and all the keys need to replay, 2063 * so the number of RESERVE_BTREE type buckets should be as much 2064 * as journal buckets 2065 */ 2066 btree_buckets = ca->sb.njournal_buckets ?: 8; 2067 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2068 2069 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) || 2070 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 2071 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 2072 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 2073 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 2074 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 2075 !(ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2076 ca->sb.nbuckets))) || 2077 !(ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2078 prio_buckets(ca), 2), 2079 GFP_KERNEL)) || 2080 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 2081 return -ENOMEM; 2082 2083 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2084 2085 for_each_bucket(b, ca) 2086 atomic_set(&b->pin, 0); 2087 2088 return 0; 2089 } 2090 2091 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2092 struct block_device *bdev, struct cache *ca) 2093 { 2094 const char *err = NULL; /* must be set for any error case */ 2095 int ret = 0; 2096 2097 bdevname(bdev, ca->cache_dev_name); 2098 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2099 ca->bdev = bdev; 2100 ca->bdev->bd_holder = ca; 2101 2102 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2103 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2104 get_page(sb_page); 2105 2106 if (blk_queue_discard(bdev_get_queue(bdev))) 2107 ca->discard = CACHE_DISCARD(&ca->sb); 2108 2109 ret = cache_alloc(ca); 2110 if (ret != 0) { 2111 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2112 if (ret == -ENOMEM) 2113 err = "cache_alloc(): -ENOMEM"; 2114 else 2115 err = "cache_alloc(): unknown error"; 2116 goto err; 2117 } 2118 2119 if (kobject_add(&ca->kobj, 2120 &part_to_dev(bdev->bd_part)->kobj, 2121 "bcache")) { 2122 err = "error calling kobject_add"; 2123 ret = -ENOMEM; 2124 goto out; 2125 } 2126 2127 mutex_lock(&bch_register_lock); 2128 err = register_cache_set(ca); 2129 mutex_unlock(&bch_register_lock); 2130 2131 if (err) { 2132 ret = -ENODEV; 2133 goto out; 2134 } 2135 2136 pr_info("registered cache device %s", ca->cache_dev_name); 2137 2138 out: 2139 kobject_put(&ca->kobj); 2140 2141 err: 2142 if (err) 2143 pr_notice("error %s: %s", ca->cache_dev_name, err); 2144 2145 return ret; 2146 } 2147 2148 /* Global interfaces/init */ 2149 2150 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2151 const char *buffer, size_t size); 2152 2153 kobj_attribute_write(register, register_bcache); 2154 kobj_attribute_write(register_quiet, register_bcache); 2155 2156 static bool bch_is_open_backing(struct block_device *bdev) 2157 { 2158 struct cache_set *c, *tc; 2159 struct cached_dev *dc, *t; 2160 2161 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2162 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2163 if (dc->bdev == bdev) 2164 return true; 2165 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2166 if (dc->bdev == bdev) 2167 return true; 2168 return false; 2169 } 2170 2171 static bool bch_is_open_cache(struct block_device *bdev) 2172 { 2173 struct cache_set *c, *tc; 2174 struct cache *ca; 2175 unsigned int i; 2176 2177 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2178 for_each_cache(ca, c, i) 2179 if (ca->bdev == bdev) 2180 return true; 2181 return false; 2182 } 2183 2184 static bool bch_is_open(struct block_device *bdev) 2185 { 2186 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2187 } 2188 2189 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2190 const char *buffer, size_t size) 2191 { 2192 ssize_t ret = size; 2193 const char *err = "cannot allocate memory"; 2194 char *path = NULL; 2195 struct cache_sb *sb = NULL; 2196 struct block_device *bdev = NULL; 2197 struct page *sb_page = NULL; 2198 2199 if (!try_module_get(THIS_MODULE)) 2200 return -EBUSY; 2201 2202 path = kstrndup(buffer, size, GFP_KERNEL); 2203 if (!path) 2204 goto err; 2205 2206 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); 2207 if (!sb) 2208 goto err; 2209 2210 err = "failed to open device"; 2211 bdev = blkdev_get_by_path(strim(path), 2212 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2213 sb); 2214 if (IS_ERR(bdev)) { 2215 if (bdev == ERR_PTR(-EBUSY)) { 2216 bdev = lookup_bdev(strim(path)); 2217 mutex_lock(&bch_register_lock); 2218 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2219 err = "device already registered"; 2220 else 2221 err = "device busy"; 2222 mutex_unlock(&bch_register_lock); 2223 if (!IS_ERR(bdev)) 2224 bdput(bdev); 2225 if (attr == &ksysfs_register_quiet) 2226 goto out; 2227 } 2228 goto err; 2229 } 2230 2231 err = "failed to set blocksize"; 2232 if (set_blocksize(bdev, 4096)) 2233 goto err_close; 2234 2235 err = read_super(sb, bdev, &sb_page); 2236 if (err) 2237 goto err_close; 2238 2239 err = "failed to register device"; 2240 if (SB_IS_BDEV(sb)) { 2241 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2242 2243 if (!dc) 2244 goto err_close; 2245 2246 mutex_lock(&bch_register_lock); 2247 register_bdev(sb, sb_page, bdev, dc); 2248 mutex_unlock(&bch_register_lock); 2249 } else { 2250 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2251 2252 if (!ca) 2253 goto err_close; 2254 2255 if (register_cache(sb, sb_page, bdev, ca) != 0) 2256 goto err; 2257 } 2258 out: 2259 if (sb_page) 2260 put_page(sb_page); 2261 kfree(sb); 2262 kfree(path); 2263 module_put(THIS_MODULE); 2264 return ret; 2265 2266 err_close: 2267 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2268 err: 2269 pr_info("error %s: %s", path, err); 2270 ret = -EINVAL; 2271 goto out; 2272 } 2273 2274 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2275 { 2276 if (code == SYS_DOWN || 2277 code == SYS_HALT || 2278 code == SYS_POWER_OFF) { 2279 DEFINE_WAIT(wait); 2280 unsigned long start = jiffies; 2281 bool stopped = false; 2282 2283 struct cache_set *c, *tc; 2284 struct cached_dev *dc, *tdc; 2285 2286 mutex_lock(&bch_register_lock); 2287 2288 if (list_empty(&bch_cache_sets) && 2289 list_empty(&uncached_devices)) 2290 goto out; 2291 2292 pr_info("Stopping all devices:"); 2293 2294 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2295 bch_cache_set_stop(c); 2296 2297 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2298 bcache_device_stop(&dc->disk); 2299 2300 /* What's a condition variable? */ 2301 while (1) { 2302 long timeout = start + 2 * HZ - jiffies; 2303 2304 stopped = list_empty(&bch_cache_sets) && 2305 list_empty(&uncached_devices); 2306 2307 if (timeout < 0 || stopped) 2308 break; 2309 2310 prepare_to_wait(&unregister_wait, &wait, 2311 TASK_UNINTERRUPTIBLE); 2312 2313 mutex_unlock(&bch_register_lock); 2314 schedule_timeout(timeout); 2315 mutex_lock(&bch_register_lock); 2316 } 2317 2318 finish_wait(&unregister_wait, &wait); 2319 2320 if (stopped) 2321 pr_info("All devices stopped"); 2322 else 2323 pr_notice("Timeout waiting for devices to be closed"); 2324 out: 2325 mutex_unlock(&bch_register_lock); 2326 } 2327 2328 return NOTIFY_DONE; 2329 } 2330 2331 static struct notifier_block reboot = { 2332 .notifier_call = bcache_reboot, 2333 .priority = INT_MAX, /* before any real devices */ 2334 }; 2335 2336 static void bcache_exit(void) 2337 { 2338 bch_debug_exit(); 2339 bch_request_exit(); 2340 if (bcache_kobj) 2341 kobject_put(bcache_kobj); 2342 if (bcache_wq) 2343 destroy_workqueue(bcache_wq); 2344 if (bcache_major) 2345 unregister_blkdev(bcache_major, "bcache"); 2346 unregister_reboot_notifier(&reboot); 2347 mutex_destroy(&bch_register_lock); 2348 } 2349 2350 static int __init bcache_init(void) 2351 { 2352 static const struct attribute *files[] = { 2353 &ksysfs_register.attr, 2354 &ksysfs_register_quiet.attr, 2355 NULL 2356 }; 2357 2358 mutex_init(&bch_register_lock); 2359 init_waitqueue_head(&unregister_wait); 2360 register_reboot_notifier(&reboot); 2361 2362 bcache_major = register_blkdev(0, "bcache"); 2363 if (bcache_major < 0) { 2364 unregister_reboot_notifier(&reboot); 2365 mutex_destroy(&bch_register_lock); 2366 return bcache_major; 2367 } 2368 2369 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); 2370 if (!bcache_wq) 2371 goto err; 2372 2373 bcache_kobj = kobject_create_and_add("bcache", fs_kobj); 2374 if (!bcache_kobj) 2375 goto err; 2376 2377 if (bch_request_init() || 2378 sysfs_create_files(bcache_kobj, files)) 2379 goto err; 2380 2381 bch_debug_init(bcache_kobj); 2382 closure_debug_init(); 2383 2384 return 0; 2385 err: 2386 bcache_exit(); 2387 return -ENOMEM; 2388 } 2389 2390 module_exit(bcache_exit); 2391 module_init(bcache_init); 2392