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 struct workqueue_struct *bch_journal_wq; 51 52 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 53 /* limitation of partitions number on single bcache device */ 54 #define BCACHE_MINORS 128 55 /* limitation of bcache devices number on single system */ 56 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 57 58 /* Superblock */ 59 60 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 61 struct page **res) 62 { 63 const char *err; 64 struct cache_sb *s; 65 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 66 unsigned int i; 67 68 if (!bh) 69 return "IO error"; 70 71 s = (struct cache_sb *) bh->b_data; 72 73 sb->offset = le64_to_cpu(s->offset); 74 sb->version = le64_to_cpu(s->version); 75 76 memcpy(sb->magic, s->magic, 16); 77 memcpy(sb->uuid, s->uuid, 16); 78 memcpy(sb->set_uuid, s->set_uuid, 16); 79 memcpy(sb->label, s->label, SB_LABEL_SIZE); 80 81 sb->flags = le64_to_cpu(s->flags); 82 sb->seq = le64_to_cpu(s->seq); 83 sb->last_mount = le32_to_cpu(s->last_mount); 84 sb->first_bucket = le16_to_cpu(s->first_bucket); 85 sb->keys = le16_to_cpu(s->keys); 86 87 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 88 sb->d[i] = le64_to_cpu(s->d[i]); 89 90 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 91 sb->version, sb->flags, sb->seq, sb->keys); 92 93 err = "Not a bcache superblock"; 94 if (sb->offset != SB_SECTOR) 95 goto err; 96 97 if (memcmp(sb->magic, bcache_magic, 16)) 98 goto err; 99 100 err = "Too many journal buckets"; 101 if (sb->keys > SB_JOURNAL_BUCKETS) 102 goto err; 103 104 err = "Bad checksum"; 105 if (s->csum != csum_set(s)) 106 goto err; 107 108 err = "Bad UUID"; 109 if (bch_is_zero(sb->uuid, 16)) 110 goto err; 111 112 sb->block_size = le16_to_cpu(s->block_size); 113 114 err = "Superblock block size smaller than device block size"; 115 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 116 goto err; 117 118 switch (sb->version) { 119 case BCACHE_SB_VERSION_BDEV: 120 sb->data_offset = BDEV_DATA_START_DEFAULT; 121 break; 122 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 123 sb->data_offset = le64_to_cpu(s->data_offset); 124 125 err = "Bad data offset"; 126 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 127 goto err; 128 129 break; 130 case BCACHE_SB_VERSION_CDEV: 131 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 132 sb->nbuckets = le64_to_cpu(s->nbuckets); 133 sb->bucket_size = le16_to_cpu(s->bucket_size); 134 135 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 136 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 137 138 err = "Too many buckets"; 139 if (sb->nbuckets > LONG_MAX) 140 goto err; 141 142 err = "Not enough buckets"; 143 if (sb->nbuckets < 1 << 7) 144 goto err; 145 146 err = "Bad block/bucket size"; 147 if (!is_power_of_2(sb->block_size) || 148 sb->block_size > PAGE_SECTORS || 149 !is_power_of_2(sb->bucket_size) || 150 sb->bucket_size < PAGE_SECTORS) 151 goto err; 152 153 err = "Invalid superblock: device too small"; 154 if (get_capacity(bdev->bd_disk) < 155 sb->bucket_size * sb->nbuckets) 156 goto err; 157 158 err = "Bad UUID"; 159 if (bch_is_zero(sb->set_uuid, 16)) 160 goto err; 161 162 err = "Bad cache device number in set"; 163 if (!sb->nr_in_set || 164 sb->nr_in_set <= sb->nr_this_dev || 165 sb->nr_in_set > MAX_CACHES_PER_SET) 166 goto err; 167 168 err = "Journal buckets not sequential"; 169 for (i = 0; i < sb->keys; i++) 170 if (sb->d[i] != sb->first_bucket + i) 171 goto err; 172 173 err = "Too many journal buckets"; 174 if (sb->first_bucket + sb->keys > sb->nbuckets) 175 goto err; 176 177 err = "Invalid superblock: first bucket comes before end of super"; 178 if (sb->first_bucket * sb->bucket_size < 16) 179 goto err; 180 181 break; 182 default: 183 err = "Unsupported superblock version"; 184 goto err; 185 } 186 187 sb->last_mount = (u32)ktime_get_real_seconds(); 188 err = NULL; 189 190 get_page(bh->b_page); 191 *res = bh->b_page; 192 err: 193 put_bh(bh); 194 return err; 195 } 196 197 static void write_bdev_super_endio(struct bio *bio) 198 { 199 struct cached_dev *dc = bio->bi_private; 200 /* XXX: error checking */ 201 202 closure_put(&dc->sb_write); 203 } 204 205 static void __write_super(struct cache_sb *sb, struct bio *bio) 206 { 207 struct cache_sb *out = page_address(bio_first_page_all(bio)); 208 unsigned int i; 209 210 bio->bi_iter.bi_sector = SB_SECTOR; 211 bio->bi_iter.bi_size = SB_SIZE; 212 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 213 bch_bio_map(bio, NULL); 214 215 out->offset = cpu_to_le64(sb->offset); 216 out->version = cpu_to_le64(sb->version); 217 218 memcpy(out->uuid, sb->uuid, 16); 219 memcpy(out->set_uuid, sb->set_uuid, 16); 220 memcpy(out->label, sb->label, SB_LABEL_SIZE); 221 222 out->flags = cpu_to_le64(sb->flags); 223 out->seq = cpu_to_le64(sb->seq); 224 225 out->last_mount = cpu_to_le32(sb->last_mount); 226 out->first_bucket = cpu_to_le16(sb->first_bucket); 227 out->keys = cpu_to_le16(sb->keys); 228 229 for (i = 0; i < sb->keys; i++) 230 out->d[i] = cpu_to_le64(sb->d[i]); 231 232 out->csum = csum_set(out); 233 234 pr_debug("ver %llu, flags %llu, seq %llu", 235 sb->version, sb->flags, sb->seq); 236 237 submit_bio(bio); 238 } 239 240 static void bch_write_bdev_super_unlock(struct closure *cl) 241 { 242 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 243 244 up(&dc->sb_write_mutex); 245 } 246 247 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 248 { 249 struct closure *cl = &dc->sb_write; 250 struct bio *bio = &dc->sb_bio; 251 252 down(&dc->sb_write_mutex); 253 closure_init(cl, parent); 254 255 bio_reset(bio); 256 bio_set_dev(bio, dc->bdev); 257 bio->bi_end_io = write_bdev_super_endio; 258 bio->bi_private = dc; 259 260 closure_get(cl); 261 /* I/O request sent to backing device */ 262 __write_super(&dc->sb, bio); 263 264 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 265 } 266 267 static void write_super_endio(struct bio *bio) 268 { 269 struct cache *ca = bio->bi_private; 270 271 /* is_read = 0 */ 272 bch_count_io_errors(ca, bio->bi_status, 0, 273 "writing superblock"); 274 closure_put(&ca->set->sb_write); 275 } 276 277 static void bcache_write_super_unlock(struct closure *cl) 278 { 279 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 280 281 up(&c->sb_write_mutex); 282 } 283 284 void bcache_write_super(struct cache_set *c) 285 { 286 struct closure *cl = &c->sb_write; 287 struct cache *ca; 288 unsigned int i; 289 290 down(&c->sb_write_mutex); 291 closure_init(cl, &c->cl); 292 293 c->sb.seq++; 294 295 for_each_cache(ca, c, i) { 296 struct bio *bio = &ca->sb_bio; 297 298 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 299 ca->sb.seq = c->sb.seq; 300 ca->sb.last_mount = c->sb.last_mount; 301 302 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 303 304 bio_reset(bio); 305 bio_set_dev(bio, ca->bdev); 306 bio->bi_end_io = write_super_endio; 307 bio->bi_private = ca; 308 309 closure_get(cl); 310 __write_super(&ca->sb, bio); 311 } 312 313 closure_return_with_destructor(cl, bcache_write_super_unlock); 314 } 315 316 /* UUID io */ 317 318 static void uuid_endio(struct bio *bio) 319 { 320 struct closure *cl = bio->bi_private; 321 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 322 323 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 324 bch_bbio_free(bio, c); 325 closure_put(cl); 326 } 327 328 static void uuid_io_unlock(struct closure *cl) 329 { 330 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 331 332 up(&c->uuid_write_mutex); 333 } 334 335 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 336 struct bkey *k, struct closure *parent) 337 { 338 struct closure *cl = &c->uuid_write; 339 struct uuid_entry *u; 340 unsigned int i; 341 char buf[80]; 342 343 BUG_ON(!parent); 344 down(&c->uuid_write_mutex); 345 closure_init(cl, parent); 346 347 for (i = 0; i < KEY_PTRS(k); i++) { 348 struct bio *bio = bch_bbio_alloc(c); 349 350 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 351 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 352 353 bio->bi_end_io = uuid_endio; 354 bio->bi_private = cl; 355 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 356 bch_bio_map(bio, c->uuids); 357 358 bch_submit_bbio(bio, c, k, i); 359 360 if (op != REQ_OP_WRITE) 361 break; 362 } 363 364 bch_extent_to_text(buf, sizeof(buf), k); 365 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 366 367 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 368 if (!bch_is_zero(u->uuid, 16)) 369 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 370 u - c->uuids, u->uuid, u->label, 371 u->first_reg, u->last_reg, u->invalidated); 372 373 closure_return_with_destructor(cl, uuid_io_unlock); 374 } 375 376 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 377 { 378 struct bkey *k = &j->uuid_bucket; 379 380 if (__bch_btree_ptr_invalid(c, k)) 381 return "bad uuid pointer"; 382 383 bkey_copy(&c->uuid_bucket, k); 384 uuid_io(c, REQ_OP_READ, 0, k, cl); 385 386 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 387 struct uuid_entry_v0 *u0 = (void *) c->uuids; 388 struct uuid_entry *u1 = (void *) c->uuids; 389 int i; 390 391 closure_sync(cl); 392 393 /* 394 * Since the new uuid entry is bigger than the old, we have to 395 * convert starting at the highest memory address and work down 396 * in order to do it in place 397 */ 398 399 for (i = c->nr_uuids - 1; 400 i >= 0; 401 --i) { 402 memcpy(u1[i].uuid, u0[i].uuid, 16); 403 memcpy(u1[i].label, u0[i].label, 32); 404 405 u1[i].first_reg = u0[i].first_reg; 406 u1[i].last_reg = u0[i].last_reg; 407 u1[i].invalidated = u0[i].invalidated; 408 409 u1[i].flags = 0; 410 u1[i].sectors = 0; 411 } 412 } 413 414 return NULL; 415 } 416 417 static int __uuid_write(struct cache_set *c) 418 { 419 BKEY_PADDED(key) k; 420 struct closure cl; 421 422 closure_init_stack(&cl); 423 lockdep_assert_held(&bch_register_lock); 424 425 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 426 return 1; 427 428 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 429 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 430 closure_sync(&cl); 431 432 bkey_copy(&c->uuid_bucket, &k.key); 433 bkey_put(c, &k.key); 434 return 0; 435 } 436 437 int bch_uuid_write(struct cache_set *c) 438 { 439 int ret = __uuid_write(c); 440 441 if (!ret) 442 bch_journal_meta(c, NULL); 443 444 return ret; 445 } 446 447 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 448 { 449 struct uuid_entry *u; 450 451 for (u = c->uuids; 452 u < c->uuids + c->nr_uuids; u++) 453 if (!memcmp(u->uuid, uuid, 16)) 454 return u; 455 456 return NULL; 457 } 458 459 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 460 { 461 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 462 463 return uuid_find(c, zero_uuid); 464 } 465 466 /* 467 * Bucket priorities/gens: 468 * 469 * For each bucket, we store on disk its 470 * 8 bit gen 471 * 16 bit priority 472 * 473 * See alloc.c for an explanation of the gen. The priority is used to implement 474 * lru (and in the future other) cache replacement policies; for most purposes 475 * it's just an opaque integer. 476 * 477 * The gens and the priorities don't have a whole lot to do with each other, and 478 * it's actually the gens that must be written out at specific times - it's no 479 * big deal if the priorities don't get written, if we lose them we just reuse 480 * buckets in suboptimal order. 481 * 482 * On disk they're stored in a packed array, and in as many buckets are required 483 * to fit them all. The buckets we use to store them form a list; the journal 484 * header points to the first bucket, the first bucket points to the second 485 * bucket, et cetera. 486 * 487 * This code is used by the allocation code; periodically (whenever it runs out 488 * of buckets to allocate from) the allocation code will invalidate some 489 * buckets, but it can't use those buckets until their new gens are safely on 490 * disk. 491 */ 492 493 static void prio_endio(struct bio *bio) 494 { 495 struct cache *ca = bio->bi_private; 496 497 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 498 bch_bbio_free(bio, ca->set); 499 closure_put(&ca->prio); 500 } 501 502 static void prio_io(struct cache *ca, uint64_t bucket, int op, 503 unsigned long op_flags) 504 { 505 struct closure *cl = &ca->prio; 506 struct bio *bio = bch_bbio_alloc(ca->set); 507 508 closure_init_stack(cl); 509 510 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 511 bio_set_dev(bio, ca->bdev); 512 bio->bi_iter.bi_size = bucket_bytes(ca); 513 514 bio->bi_end_io = prio_endio; 515 bio->bi_private = ca; 516 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 517 bch_bio_map(bio, ca->disk_buckets); 518 519 closure_bio_submit(ca->set, bio, &ca->prio); 520 closure_sync(cl); 521 } 522 523 void bch_prio_write(struct cache *ca) 524 { 525 int i; 526 struct bucket *b; 527 struct closure cl; 528 529 closure_init_stack(&cl); 530 531 lockdep_assert_held(&ca->set->bucket_lock); 532 533 ca->disk_buckets->seq++; 534 535 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 536 &ca->meta_sectors_written); 537 538 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 539 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 540 541 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 542 long bucket; 543 struct prio_set *p = ca->disk_buckets; 544 struct bucket_disk *d = p->data; 545 struct bucket_disk *end = d + prios_per_bucket(ca); 546 547 for (b = ca->buckets + i * prios_per_bucket(ca); 548 b < ca->buckets + ca->sb.nbuckets && d < end; 549 b++, d++) { 550 d->prio = cpu_to_le16(b->prio); 551 d->gen = b->gen; 552 } 553 554 p->next_bucket = ca->prio_buckets[i + 1]; 555 p->magic = pset_magic(&ca->sb); 556 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 557 558 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 559 BUG_ON(bucket == -1); 560 561 mutex_unlock(&ca->set->bucket_lock); 562 prio_io(ca, bucket, REQ_OP_WRITE, 0); 563 mutex_lock(&ca->set->bucket_lock); 564 565 ca->prio_buckets[i] = bucket; 566 atomic_dec_bug(&ca->buckets[bucket].pin); 567 } 568 569 mutex_unlock(&ca->set->bucket_lock); 570 571 bch_journal_meta(ca->set, &cl); 572 closure_sync(&cl); 573 574 mutex_lock(&ca->set->bucket_lock); 575 576 /* 577 * Don't want the old priorities to get garbage collected until after we 578 * finish writing the new ones, and they're journalled 579 */ 580 for (i = 0; i < prio_buckets(ca); i++) { 581 if (ca->prio_last_buckets[i]) 582 __bch_bucket_free(ca, 583 &ca->buckets[ca->prio_last_buckets[i]]); 584 585 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 586 } 587 } 588 589 static void prio_read(struct cache *ca, uint64_t bucket) 590 { 591 struct prio_set *p = ca->disk_buckets; 592 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 593 struct bucket *b; 594 unsigned int bucket_nr = 0; 595 596 for (b = ca->buckets; 597 b < ca->buckets + ca->sb.nbuckets; 598 b++, d++) { 599 if (d == end) { 600 ca->prio_buckets[bucket_nr] = bucket; 601 ca->prio_last_buckets[bucket_nr] = bucket; 602 bucket_nr++; 603 604 prio_io(ca, bucket, REQ_OP_READ, 0); 605 606 if (p->csum != 607 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 608 pr_warn("bad csum reading priorities"); 609 610 if (p->magic != pset_magic(&ca->sb)) 611 pr_warn("bad magic reading priorities"); 612 613 bucket = p->next_bucket; 614 d = p->data; 615 } 616 617 b->prio = le16_to_cpu(d->prio); 618 b->gen = b->last_gc = d->gen; 619 } 620 } 621 622 /* Bcache device */ 623 624 static int open_dev(struct block_device *b, fmode_t mode) 625 { 626 struct bcache_device *d = b->bd_disk->private_data; 627 628 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 629 return -ENXIO; 630 631 closure_get(&d->cl); 632 return 0; 633 } 634 635 static void release_dev(struct gendisk *b, fmode_t mode) 636 { 637 struct bcache_device *d = b->private_data; 638 639 closure_put(&d->cl); 640 } 641 642 static int ioctl_dev(struct block_device *b, fmode_t mode, 643 unsigned int cmd, unsigned long arg) 644 { 645 struct bcache_device *d = b->bd_disk->private_data; 646 struct cached_dev *dc = container_of(d, struct cached_dev, disk); 647 648 if (dc->io_disable) 649 return -EIO; 650 651 return d->ioctl(d, mode, cmd, arg); 652 } 653 654 static const struct block_device_operations bcache_ops = { 655 .open = open_dev, 656 .release = release_dev, 657 .ioctl = ioctl_dev, 658 .owner = THIS_MODULE, 659 }; 660 661 void bcache_device_stop(struct bcache_device *d) 662 { 663 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 664 closure_queue(&d->cl); 665 } 666 667 static void bcache_device_unlink(struct bcache_device *d) 668 { 669 lockdep_assert_held(&bch_register_lock); 670 671 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 672 unsigned int i; 673 struct cache *ca; 674 675 sysfs_remove_link(&d->c->kobj, d->name); 676 sysfs_remove_link(&d->kobj, "cache"); 677 678 for_each_cache(ca, d->c, i) 679 bd_unlink_disk_holder(ca->bdev, d->disk); 680 } 681 } 682 683 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 684 const char *name) 685 { 686 unsigned int i; 687 struct cache *ca; 688 689 for_each_cache(ca, d->c, i) 690 bd_link_disk_holder(ca->bdev, d->disk); 691 692 snprintf(d->name, BCACHEDEVNAME_SIZE, 693 "%s%u", name, d->id); 694 695 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || 696 sysfs_create_link(&c->kobj, &d->kobj, d->name), 697 "Couldn't create device <-> cache set symlinks"); 698 699 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 700 } 701 702 static void bcache_device_detach(struct bcache_device *d) 703 { 704 lockdep_assert_held(&bch_register_lock); 705 706 atomic_dec(&d->c->attached_dev_nr); 707 708 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 709 struct uuid_entry *u = d->c->uuids + d->id; 710 711 SET_UUID_FLASH_ONLY(u, 0); 712 memcpy(u->uuid, invalid_uuid, 16); 713 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 714 bch_uuid_write(d->c); 715 } 716 717 bcache_device_unlink(d); 718 719 d->c->devices[d->id] = NULL; 720 closure_put(&d->c->caching); 721 d->c = NULL; 722 } 723 724 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 725 unsigned int id) 726 { 727 d->id = id; 728 d->c = c; 729 c->devices[id] = d; 730 731 if (id >= c->devices_max_used) 732 c->devices_max_used = id + 1; 733 734 closure_get(&c->caching); 735 } 736 737 static inline int first_minor_to_idx(int first_minor) 738 { 739 return (first_minor/BCACHE_MINORS); 740 } 741 742 static inline int idx_to_first_minor(int idx) 743 { 744 return (idx * BCACHE_MINORS); 745 } 746 747 static void bcache_device_free(struct bcache_device *d) 748 { 749 lockdep_assert_held(&bch_register_lock); 750 751 pr_info("%s stopped", d->disk->disk_name); 752 753 if (d->c) 754 bcache_device_detach(d); 755 if (d->disk && d->disk->flags & GENHD_FL_UP) 756 del_gendisk(d->disk); 757 if (d->disk && d->disk->queue) 758 blk_cleanup_queue(d->disk->queue); 759 if (d->disk) { 760 ida_simple_remove(&bcache_device_idx, 761 first_minor_to_idx(d->disk->first_minor)); 762 put_disk(d->disk); 763 } 764 765 bioset_exit(&d->bio_split); 766 kvfree(d->full_dirty_stripes); 767 kvfree(d->stripe_sectors_dirty); 768 769 closure_debug_destroy(&d->cl); 770 } 771 772 static int bcache_device_init(struct bcache_device *d, unsigned int block_size, 773 sector_t sectors) 774 { 775 struct request_queue *q; 776 const size_t max_stripes = min_t(size_t, INT_MAX, 777 SIZE_MAX / sizeof(atomic_t)); 778 size_t n; 779 int idx; 780 781 if (!d->stripe_size) 782 d->stripe_size = 1 << 31; 783 784 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 785 786 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 787 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 788 (unsigned int)d->nr_stripes); 789 return -ENOMEM; 790 } 791 792 n = d->nr_stripes * sizeof(atomic_t); 793 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 794 if (!d->stripe_sectors_dirty) 795 return -ENOMEM; 796 797 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 798 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 799 if (!d->full_dirty_stripes) 800 return -ENOMEM; 801 802 idx = ida_simple_get(&bcache_device_idx, 0, 803 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 804 if (idx < 0) 805 return idx; 806 807 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 808 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) 809 goto err; 810 811 d->disk = alloc_disk(BCACHE_MINORS); 812 if (!d->disk) 813 goto err; 814 815 set_capacity(d->disk, sectors); 816 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 817 818 d->disk->major = bcache_major; 819 d->disk->first_minor = idx_to_first_minor(idx); 820 d->disk->fops = &bcache_ops; 821 d->disk->private_data = d; 822 823 q = blk_alloc_queue(GFP_KERNEL); 824 if (!q) 825 return -ENOMEM; 826 827 blk_queue_make_request(q, NULL); 828 d->disk->queue = q; 829 q->queuedata = d; 830 q->backing_dev_info->congested_data = d; 831 q->limits.max_hw_sectors = UINT_MAX; 832 q->limits.max_sectors = UINT_MAX; 833 q->limits.max_segment_size = UINT_MAX; 834 q->limits.max_segments = BIO_MAX_PAGES; 835 blk_queue_max_discard_sectors(q, UINT_MAX); 836 q->limits.discard_granularity = 512; 837 q->limits.io_min = block_size; 838 q->limits.logical_block_size = block_size; 839 q->limits.physical_block_size = block_size; 840 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 841 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 842 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 843 844 blk_queue_write_cache(q, true, true); 845 846 return 0; 847 848 err: 849 ida_simple_remove(&bcache_device_idx, idx); 850 return -ENOMEM; 851 852 } 853 854 /* Cached device */ 855 856 static void calc_cached_dev_sectors(struct cache_set *c) 857 { 858 uint64_t sectors = 0; 859 struct cached_dev *dc; 860 861 list_for_each_entry(dc, &c->cached_devs, list) 862 sectors += bdev_sectors(dc->bdev); 863 864 c->cached_dev_sectors = sectors; 865 } 866 867 #define BACKING_DEV_OFFLINE_TIMEOUT 5 868 static int cached_dev_status_update(void *arg) 869 { 870 struct cached_dev *dc = arg; 871 struct request_queue *q; 872 873 /* 874 * If this delayed worker is stopping outside, directly quit here. 875 * dc->io_disable might be set via sysfs interface, so check it 876 * here too. 877 */ 878 while (!kthread_should_stop() && !dc->io_disable) { 879 q = bdev_get_queue(dc->bdev); 880 if (blk_queue_dying(q)) 881 dc->offline_seconds++; 882 else 883 dc->offline_seconds = 0; 884 885 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 886 pr_err("%s: device offline for %d seconds", 887 dc->backing_dev_name, 888 BACKING_DEV_OFFLINE_TIMEOUT); 889 pr_err("%s: disable I/O request due to backing " 890 "device offline", dc->disk.name); 891 dc->io_disable = true; 892 /* let others know earlier that io_disable is true */ 893 smp_mb(); 894 bcache_device_stop(&dc->disk); 895 break; 896 } 897 schedule_timeout_interruptible(HZ); 898 } 899 900 wait_for_kthread_stop(); 901 return 0; 902 } 903 904 905 void bch_cached_dev_run(struct cached_dev *dc) 906 { 907 struct bcache_device *d = &dc->disk; 908 char buf[SB_LABEL_SIZE + 1]; 909 char *env[] = { 910 "DRIVER=bcache", 911 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 912 NULL, 913 NULL, 914 }; 915 916 memcpy(buf, dc->sb.label, SB_LABEL_SIZE); 917 buf[SB_LABEL_SIZE] = '\0'; 918 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); 919 920 if (atomic_xchg(&dc->running, 1)) { 921 kfree(env[1]); 922 kfree(env[2]); 923 return; 924 } 925 926 if (!d->c && 927 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 928 struct closure cl; 929 930 closure_init_stack(&cl); 931 932 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 933 bch_write_bdev_super(dc, &cl); 934 closure_sync(&cl); 935 } 936 937 add_disk(d->disk); 938 bd_link_disk_holder(dc->bdev, dc->disk.disk); 939 /* 940 * won't show up in the uevent file, use udevadm monitor -e instead 941 * only class / kset properties are persistent 942 */ 943 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 944 kfree(env[1]); 945 kfree(env[2]); 946 947 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 948 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) 949 pr_debug("error creating sysfs link"); 950 951 dc->status_update_thread = kthread_run(cached_dev_status_update, 952 dc, "bcache_status_update"); 953 if (IS_ERR(dc->status_update_thread)) { 954 pr_warn("failed to create bcache_status_update kthread, " 955 "continue to run without monitoring backing " 956 "device status"); 957 } 958 } 959 960 /* 961 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 962 * work dc->writeback_rate_update is running. Wait until the routine 963 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 964 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 965 * seconds, give up waiting here and continue to cancel it too. 966 */ 967 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 968 { 969 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 970 971 do { 972 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 973 &dc->disk.flags)) 974 break; 975 time_out--; 976 schedule_timeout_interruptible(1); 977 } while (time_out > 0); 978 979 if (time_out == 0) 980 pr_warn("give up waiting for dc->writeback_write_update to quit"); 981 982 cancel_delayed_work_sync(&dc->writeback_rate_update); 983 } 984 985 static void cached_dev_detach_finish(struct work_struct *w) 986 { 987 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 988 struct closure cl; 989 990 closure_init_stack(&cl); 991 992 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 993 BUG_ON(refcount_read(&dc->count)); 994 995 mutex_lock(&bch_register_lock); 996 997 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 998 cancel_writeback_rate_update_dwork(dc); 999 1000 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 1001 kthread_stop(dc->writeback_thread); 1002 dc->writeback_thread = NULL; 1003 } 1004 1005 memset(&dc->sb.set_uuid, 0, 16); 1006 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 1007 1008 bch_write_bdev_super(dc, &cl); 1009 closure_sync(&cl); 1010 1011 bcache_device_detach(&dc->disk); 1012 list_move(&dc->list, &uncached_devices); 1013 1014 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1015 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1016 1017 mutex_unlock(&bch_register_lock); 1018 1019 pr_info("Caching disabled for %s", dc->backing_dev_name); 1020 1021 /* Drop ref we took in cached_dev_detach() */ 1022 closure_put(&dc->disk.cl); 1023 } 1024 1025 void bch_cached_dev_detach(struct cached_dev *dc) 1026 { 1027 lockdep_assert_held(&bch_register_lock); 1028 1029 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1030 return; 1031 1032 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1033 return; 1034 1035 /* 1036 * Block the device from being closed and freed until we're finished 1037 * detaching 1038 */ 1039 closure_get(&dc->disk.cl); 1040 1041 bch_writeback_queue(dc); 1042 1043 cached_dev_put(dc); 1044 } 1045 1046 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1047 uint8_t *set_uuid) 1048 { 1049 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); 1050 struct uuid_entry *u; 1051 struct cached_dev *exist_dc, *t; 1052 1053 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1054 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1055 return -ENOENT; 1056 1057 if (dc->disk.c) { 1058 pr_err("Can't attach %s: already attached", 1059 dc->backing_dev_name); 1060 return -EINVAL; 1061 } 1062 1063 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1064 pr_err("Can't attach %s: shutting down", 1065 dc->backing_dev_name); 1066 return -EINVAL; 1067 } 1068 1069 if (dc->sb.block_size < c->sb.block_size) { 1070 /* Will die */ 1071 pr_err("Couldn't attach %s: block size less than set's block size", 1072 dc->backing_dev_name); 1073 return -EINVAL; 1074 } 1075 1076 /* Check whether already attached */ 1077 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1078 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1079 pr_err("Tried to attach %s but duplicate UUID already attached", 1080 dc->backing_dev_name); 1081 1082 return -EINVAL; 1083 } 1084 } 1085 1086 u = uuid_find(c, dc->sb.uuid); 1087 1088 if (u && 1089 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1090 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1091 memcpy(u->uuid, invalid_uuid, 16); 1092 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 1093 u = NULL; 1094 } 1095 1096 if (!u) { 1097 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1098 pr_err("Couldn't find uuid for %s in set", 1099 dc->backing_dev_name); 1100 return -ENOENT; 1101 } 1102 1103 u = uuid_find_empty(c); 1104 if (!u) { 1105 pr_err("Not caching %s, no room for UUID", 1106 dc->backing_dev_name); 1107 return -EINVAL; 1108 } 1109 } 1110 1111 /* 1112 * Deadlocks since we're called via sysfs... 1113 * sysfs_remove_file(&dc->kobj, &sysfs_attach); 1114 */ 1115 1116 if (bch_is_zero(u->uuid, 16)) { 1117 struct closure cl; 1118 1119 closure_init_stack(&cl); 1120 1121 memcpy(u->uuid, dc->sb.uuid, 16); 1122 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1123 u->first_reg = u->last_reg = rtime; 1124 bch_uuid_write(c); 1125 1126 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1127 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1128 1129 bch_write_bdev_super(dc, &cl); 1130 closure_sync(&cl); 1131 } else { 1132 u->last_reg = rtime; 1133 bch_uuid_write(c); 1134 } 1135 1136 bcache_device_attach(&dc->disk, c, u - c->uuids); 1137 list_move(&dc->list, &c->cached_devs); 1138 calc_cached_dev_sectors(c); 1139 1140 /* 1141 * dc->c must be set before dc->count != 0 - paired with the mb in 1142 * cached_dev_get() 1143 */ 1144 smp_wmb(); 1145 refcount_set(&dc->count, 1); 1146 1147 /* Block writeback thread, but spawn it */ 1148 down_write(&dc->writeback_lock); 1149 if (bch_cached_dev_writeback_start(dc)) { 1150 up_write(&dc->writeback_lock); 1151 return -ENOMEM; 1152 } 1153 1154 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1155 bch_sectors_dirty_init(&dc->disk); 1156 atomic_set(&dc->has_dirty, 1); 1157 bch_writeback_queue(dc); 1158 } 1159 1160 bch_cached_dev_run(dc); 1161 bcache_device_link(&dc->disk, c, "bdev"); 1162 atomic_inc(&c->attached_dev_nr); 1163 1164 /* Allow the writeback thread to proceed */ 1165 up_write(&dc->writeback_lock); 1166 1167 pr_info("Caching %s as %s on set %pU", 1168 dc->backing_dev_name, 1169 dc->disk.disk->disk_name, 1170 dc->disk.c->sb.set_uuid); 1171 return 0; 1172 } 1173 1174 void bch_cached_dev_release(struct kobject *kobj) 1175 { 1176 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1177 disk.kobj); 1178 kfree(dc); 1179 module_put(THIS_MODULE); 1180 } 1181 1182 static void cached_dev_free(struct closure *cl) 1183 { 1184 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1185 1186 mutex_lock(&bch_register_lock); 1187 1188 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1189 cancel_writeback_rate_update_dwork(dc); 1190 1191 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1192 kthread_stop(dc->writeback_thread); 1193 if (dc->writeback_write_wq) 1194 destroy_workqueue(dc->writeback_write_wq); 1195 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1196 kthread_stop(dc->status_update_thread); 1197 1198 if (atomic_read(&dc->running)) 1199 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1200 bcache_device_free(&dc->disk); 1201 list_del(&dc->list); 1202 1203 mutex_unlock(&bch_register_lock); 1204 1205 if (!IS_ERR_OR_NULL(dc->bdev)) 1206 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1207 1208 wake_up(&unregister_wait); 1209 1210 kobject_put(&dc->disk.kobj); 1211 } 1212 1213 static void cached_dev_flush(struct closure *cl) 1214 { 1215 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1216 struct bcache_device *d = &dc->disk; 1217 1218 mutex_lock(&bch_register_lock); 1219 bcache_device_unlink(d); 1220 mutex_unlock(&bch_register_lock); 1221 1222 bch_cache_accounting_destroy(&dc->accounting); 1223 kobject_del(&d->kobj); 1224 1225 continue_at(cl, cached_dev_free, system_wq); 1226 } 1227 1228 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size) 1229 { 1230 int ret; 1231 struct io *io; 1232 struct request_queue *q = bdev_get_queue(dc->bdev); 1233 1234 __module_get(THIS_MODULE); 1235 INIT_LIST_HEAD(&dc->list); 1236 closure_init(&dc->disk.cl, NULL); 1237 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1238 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1239 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1240 sema_init(&dc->sb_write_mutex, 1); 1241 INIT_LIST_HEAD(&dc->io_lru); 1242 spin_lock_init(&dc->io_lock); 1243 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1244 1245 dc->sequential_cutoff = 4 << 20; 1246 1247 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1248 list_add(&io->lru, &dc->io_lru); 1249 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1250 } 1251 1252 dc->disk.stripe_size = q->limits.io_opt >> 9; 1253 1254 if (dc->disk.stripe_size) 1255 dc->partial_stripes_expensive = 1256 q->limits.raid_partial_stripes_expensive; 1257 1258 ret = bcache_device_init(&dc->disk, block_size, 1259 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1260 if (ret) 1261 return ret; 1262 1263 dc->disk.disk->queue->backing_dev_info->ra_pages = 1264 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1265 q->backing_dev_info->ra_pages); 1266 1267 atomic_set(&dc->io_errors, 0); 1268 dc->io_disable = false; 1269 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1270 /* default to auto */ 1271 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1272 1273 bch_cached_dev_request_init(dc); 1274 bch_cached_dev_writeback_init(dc); 1275 return 0; 1276 } 1277 1278 /* Cached device - bcache superblock */ 1279 1280 static void register_bdev(struct cache_sb *sb, struct page *sb_page, 1281 struct block_device *bdev, 1282 struct cached_dev *dc) 1283 { 1284 const char *err = "cannot allocate memory"; 1285 struct cache_set *c; 1286 1287 bdevname(bdev, dc->backing_dev_name); 1288 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1289 dc->bdev = bdev; 1290 dc->bdev->bd_holder = dc; 1291 1292 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1293 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1294 get_page(sb_page); 1295 1296 1297 if (cached_dev_init(dc, sb->block_size << 9)) 1298 goto err; 1299 1300 err = "error creating kobject"; 1301 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1302 "bcache")) 1303 goto err; 1304 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1305 goto err; 1306 1307 pr_info("registered backing device %s", dc->backing_dev_name); 1308 1309 list_add(&dc->list, &uncached_devices); 1310 /* attach to a matched cache set if it exists */ 1311 list_for_each_entry(c, &bch_cache_sets, list) 1312 bch_cached_dev_attach(dc, c, NULL); 1313 1314 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1315 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) 1316 bch_cached_dev_run(dc); 1317 1318 return; 1319 err: 1320 pr_notice("error %s: %s", dc->backing_dev_name, err); 1321 bcache_device_stop(&dc->disk); 1322 } 1323 1324 /* Flash only volumes */ 1325 1326 void bch_flash_dev_release(struct kobject *kobj) 1327 { 1328 struct bcache_device *d = container_of(kobj, struct bcache_device, 1329 kobj); 1330 kfree(d); 1331 } 1332 1333 static void flash_dev_free(struct closure *cl) 1334 { 1335 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1336 1337 mutex_lock(&bch_register_lock); 1338 atomic_long_sub(bcache_dev_sectors_dirty(d), 1339 &d->c->flash_dev_dirty_sectors); 1340 bcache_device_free(d); 1341 mutex_unlock(&bch_register_lock); 1342 kobject_put(&d->kobj); 1343 } 1344 1345 static void flash_dev_flush(struct closure *cl) 1346 { 1347 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1348 1349 mutex_lock(&bch_register_lock); 1350 bcache_device_unlink(d); 1351 mutex_unlock(&bch_register_lock); 1352 kobject_del(&d->kobj); 1353 continue_at(cl, flash_dev_free, system_wq); 1354 } 1355 1356 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1357 { 1358 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1359 GFP_KERNEL); 1360 if (!d) 1361 return -ENOMEM; 1362 1363 closure_init(&d->cl, NULL); 1364 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1365 1366 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1367 1368 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1369 goto err; 1370 1371 bcache_device_attach(d, c, u - c->uuids); 1372 bch_sectors_dirty_init(d); 1373 bch_flash_dev_request_init(d); 1374 add_disk(d->disk); 1375 1376 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1377 goto err; 1378 1379 bcache_device_link(d, c, "volume"); 1380 1381 return 0; 1382 err: 1383 kobject_put(&d->kobj); 1384 return -ENOMEM; 1385 } 1386 1387 static int flash_devs_run(struct cache_set *c) 1388 { 1389 int ret = 0; 1390 struct uuid_entry *u; 1391 1392 for (u = c->uuids; 1393 u < c->uuids + c->nr_uuids && !ret; 1394 u++) 1395 if (UUID_FLASH_ONLY(u)) 1396 ret = flash_dev_run(c, u); 1397 1398 return ret; 1399 } 1400 1401 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1402 { 1403 struct uuid_entry *u; 1404 1405 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1406 return -EINTR; 1407 1408 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1409 return -EPERM; 1410 1411 u = uuid_find_empty(c); 1412 if (!u) { 1413 pr_err("Can't create volume, no room for UUID"); 1414 return -EINVAL; 1415 } 1416 1417 get_random_bytes(u->uuid, 16); 1418 memset(u->label, 0, 32); 1419 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); 1420 1421 SET_UUID_FLASH_ONLY(u, 1); 1422 u->sectors = size >> 9; 1423 1424 bch_uuid_write(c); 1425 1426 return flash_dev_run(c, u); 1427 } 1428 1429 bool bch_cached_dev_error(struct cached_dev *dc) 1430 { 1431 struct cache_set *c; 1432 1433 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1434 return false; 1435 1436 dc->io_disable = true; 1437 /* make others know io_disable is true earlier */ 1438 smp_mb(); 1439 1440 pr_err("stop %s: too many IO errors on backing device %s\n", 1441 dc->disk.disk->disk_name, dc->backing_dev_name); 1442 1443 /* 1444 * If the cached device is still attached to a cache set, 1445 * even dc->io_disable is true and no more I/O requests 1446 * accepted, cache device internal I/O (writeback scan or 1447 * garbage collection) may still prevent bcache device from 1448 * being stopped. So here CACHE_SET_IO_DISABLE should be 1449 * set to c->flags too, to make the internal I/O to cache 1450 * device rejected and stopped immediately. 1451 * If c is NULL, that means the bcache device is not attached 1452 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. 1453 */ 1454 c = dc->disk.c; 1455 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1456 pr_info("CACHE_SET_IO_DISABLE already set"); 1457 1458 bcache_device_stop(&dc->disk); 1459 return true; 1460 } 1461 1462 /* Cache set */ 1463 1464 __printf(2, 3) 1465 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1466 { 1467 va_list args; 1468 1469 if (c->on_error != ON_ERROR_PANIC && 1470 test_bit(CACHE_SET_STOPPING, &c->flags)) 1471 return false; 1472 1473 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1474 pr_info("CACHE_SET_IO_DISABLE already set"); 1475 1476 /* 1477 * XXX: we can be called from atomic context 1478 * acquire_console_sem(); 1479 */ 1480 1481 pr_err("bcache: error on %pU: ", c->sb.set_uuid); 1482 1483 va_start(args, fmt); 1484 vprintk(fmt, args); 1485 va_end(args); 1486 1487 pr_err(", disabling caching\n"); 1488 1489 if (c->on_error == ON_ERROR_PANIC) 1490 panic("panic forced after error\n"); 1491 1492 bch_cache_set_unregister(c); 1493 return true; 1494 } 1495 1496 void bch_cache_set_release(struct kobject *kobj) 1497 { 1498 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1499 1500 kfree(c); 1501 module_put(THIS_MODULE); 1502 } 1503 1504 static void cache_set_free(struct closure *cl) 1505 { 1506 struct cache_set *c = container_of(cl, struct cache_set, cl); 1507 struct cache *ca; 1508 unsigned int i; 1509 1510 if (!IS_ERR_OR_NULL(c->debug)) 1511 debugfs_remove(c->debug); 1512 1513 bch_open_buckets_free(c); 1514 bch_btree_cache_free(c); 1515 bch_journal_free(c); 1516 1517 for_each_cache(ca, c, i) 1518 if (ca) { 1519 ca->set = NULL; 1520 c->cache[ca->sb.nr_this_dev] = NULL; 1521 kobject_put(&ca->kobj); 1522 } 1523 1524 bch_bset_sort_state_free(&c->sort); 1525 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1526 1527 if (c->moving_gc_wq) 1528 destroy_workqueue(c->moving_gc_wq); 1529 bioset_exit(&c->bio_split); 1530 mempool_exit(&c->fill_iter); 1531 mempool_exit(&c->bio_meta); 1532 mempool_exit(&c->search); 1533 kfree(c->devices); 1534 1535 mutex_lock(&bch_register_lock); 1536 list_del(&c->list); 1537 mutex_unlock(&bch_register_lock); 1538 1539 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1540 wake_up(&unregister_wait); 1541 1542 closure_debug_destroy(&c->cl); 1543 kobject_put(&c->kobj); 1544 } 1545 1546 static void cache_set_flush(struct closure *cl) 1547 { 1548 struct cache_set *c = container_of(cl, struct cache_set, caching); 1549 struct cache *ca; 1550 struct btree *b; 1551 unsigned int i; 1552 1553 bch_cache_accounting_destroy(&c->accounting); 1554 1555 kobject_put(&c->internal); 1556 kobject_del(&c->kobj); 1557 1558 if (c->gc_thread) 1559 kthread_stop(c->gc_thread); 1560 1561 if (!IS_ERR_OR_NULL(c->root)) 1562 list_add(&c->root->list, &c->btree_cache); 1563 1564 /* Should skip this if we're unregistering because of an error */ 1565 list_for_each_entry(b, &c->btree_cache, list) { 1566 mutex_lock(&b->write_lock); 1567 if (btree_node_dirty(b)) 1568 __bch_btree_node_write(b, NULL); 1569 mutex_unlock(&b->write_lock); 1570 } 1571 1572 for_each_cache(ca, c, i) 1573 if (ca->alloc_thread) 1574 kthread_stop(ca->alloc_thread); 1575 1576 if (c->journal.cur) { 1577 cancel_delayed_work_sync(&c->journal.work); 1578 /* flush last journal entry if needed */ 1579 c->journal.work.work.func(&c->journal.work.work); 1580 } 1581 1582 closure_return(cl); 1583 } 1584 1585 /* 1586 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1587 * cache set is unregistering due to too many I/O errors. In this condition, 1588 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1589 * value and whether the broken cache has dirty data: 1590 * 1591 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1592 * BCH_CACHED_STOP_AUTO 0 NO 1593 * BCH_CACHED_STOP_AUTO 1 YES 1594 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1595 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1596 * 1597 * The expected behavior is, if stop_when_cache_set_failed is configured to 1598 * "auto" via sysfs interface, the bcache device will not be stopped if the 1599 * backing device is clean on the broken cache device. 1600 */ 1601 static void conditional_stop_bcache_device(struct cache_set *c, 1602 struct bcache_device *d, 1603 struct cached_dev *dc) 1604 { 1605 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1606 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1607 d->disk->disk_name, c->sb.set_uuid); 1608 bcache_device_stop(d); 1609 } else if (atomic_read(&dc->has_dirty)) { 1610 /* 1611 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1612 * and dc->has_dirty == 1 1613 */ 1614 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1615 d->disk->disk_name); 1616 /* 1617 * There might be a small time gap that cache set is 1618 * released but bcache device is not. Inside this time 1619 * gap, regular I/O requests will directly go into 1620 * backing device as no cache set attached to. This 1621 * behavior may also introduce potential inconsistence 1622 * data in writeback mode while cache is dirty. 1623 * Therefore before calling bcache_device_stop() due 1624 * to a broken cache device, dc->io_disable should be 1625 * explicitly set to true. 1626 */ 1627 dc->io_disable = true; 1628 /* make others know io_disable is true earlier */ 1629 smp_mb(); 1630 bcache_device_stop(d); 1631 } else { 1632 /* 1633 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1634 * and dc->has_dirty == 0 1635 */ 1636 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1637 d->disk->disk_name); 1638 } 1639 } 1640 1641 static void __cache_set_unregister(struct closure *cl) 1642 { 1643 struct cache_set *c = container_of(cl, struct cache_set, caching); 1644 struct cached_dev *dc; 1645 struct bcache_device *d; 1646 size_t i; 1647 1648 mutex_lock(&bch_register_lock); 1649 1650 for (i = 0; i < c->devices_max_used; i++) { 1651 d = c->devices[i]; 1652 if (!d) 1653 continue; 1654 1655 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1656 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1657 dc = container_of(d, struct cached_dev, disk); 1658 bch_cached_dev_detach(dc); 1659 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1660 conditional_stop_bcache_device(c, d, dc); 1661 } else { 1662 bcache_device_stop(d); 1663 } 1664 } 1665 1666 mutex_unlock(&bch_register_lock); 1667 1668 continue_at(cl, cache_set_flush, system_wq); 1669 } 1670 1671 void bch_cache_set_stop(struct cache_set *c) 1672 { 1673 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1674 closure_queue(&c->caching); 1675 } 1676 1677 void bch_cache_set_unregister(struct cache_set *c) 1678 { 1679 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1680 bch_cache_set_stop(c); 1681 } 1682 1683 #define alloc_bucket_pages(gfp, c) \ 1684 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1685 1686 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1687 { 1688 int iter_size; 1689 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1690 1691 if (!c) 1692 return NULL; 1693 1694 __module_get(THIS_MODULE); 1695 closure_init(&c->cl, NULL); 1696 set_closure_fn(&c->cl, cache_set_free, system_wq); 1697 1698 closure_init(&c->caching, &c->cl); 1699 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1700 1701 /* Maybe create continue_at_noreturn() and use it here? */ 1702 closure_set_stopped(&c->cl); 1703 closure_put(&c->cl); 1704 1705 kobject_init(&c->kobj, &bch_cache_set_ktype); 1706 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1707 1708 bch_cache_accounting_init(&c->accounting, &c->cl); 1709 1710 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1711 c->sb.block_size = sb->block_size; 1712 c->sb.bucket_size = sb->bucket_size; 1713 c->sb.nr_in_set = sb->nr_in_set; 1714 c->sb.last_mount = sb->last_mount; 1715 c->bucket_bits = ilog2(sb->bucket_size); 1716 c->block_bits = ilog2(sb->block_size); 1717 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1718 c->devices_max_used = 0; 1719 atomic_set(&c->attached_dev_nr, 0); 1720 c->btree_pages = bucket_pages(c); 1721 if (c->btree_pages > BTREE_MAX_PAGES) 1722 c->btree_pages = max_t(int, c->btree_pages / 4, 1723 BTREE_MAX_PAGES); 1724 1725 sema_init(&c->sb_write_mutex, 1); 1726 mutex_init(&c->bucket_lock); 1727 init_waitqueue_head(&c->btree_cache_wait); 1728 init_waitqueue_head(&c->bucket_wait); 1729 init_waitqueue_head(&c->gc_wait); 1730 sema_init(&c->uuid_write_mutex, 1); 1731 1732 spin_lock_init(&c->btree_gc_time.lock); 1733 spin_lock_init(&c->btree_split_time.lock); 1734 spin_lock_init(&c->btree_read_time.lock); 1735 1736 bch_moving_init_cache_set(c); 1737 1738 INIT_LIST_HEAD(&c->list); 1739 INIT_LIST_HEAD(&c->cached_devs); 1740 INIT_LIST_HEAD(&c->btree_cache); 1741 INIT_LIST_HEAD(&c->btree_cache_freeable); 1742 INIT_LIST_HEAD(&c->btree_cache_freed); 1743 INIT_LIST_HEAD(&c->data_buckets); 1744 1745 iter_size = (sb->bucket_size / sb->block_size + 1) * 1746 sizeof(struct btree_iter_set); 1747 1748 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1749 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1750 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1751 sizeof(struct bbio) + sizeof(struct bio_vec) * 1752 bucket_pages(c)) || 1753 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1754 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1755 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1756 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1757 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1758 WQ_MEM_RECLAIM, 0)) || 1759 bch_journal_alloc(c) || 1760 bch_btree_cache_alloc(c) || 1761 bch_open_buckets_alloc(c) || 1762 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1763 goto err; 1764 1765 c->congested_read_threshold_us = 2000; 1766 c->congested_write_threshold_us = 20000; 1767 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1768 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1769 1770 return c; 1771 err: 1772 bch_cache_set_unregister(c); 1773 return NULL; 1774 } 1775 1776 static void run_cache_set(struct cache_set *c) 1777 { 1778 const char *err = "cannot allocate memory"; 1779 struct cached_dev *dc, *t; 1780 struct cache *ca; 1781 struct closure cl; 1782 unsigned int i; 1783 1784 closure_init_stack(&cl); 1785 1786 for_each_cache(ca, c, i) 1787 c->nbuckets += ca->sb.nbuckets; 1788 set_gc_sectors(c); 1789 1790 if (CACHE_SYNC(&c->sb)) { 1791 LIST_HEAD(journal); 1792 struct bkey *k; 1793 struct jset *j; 1794 1795 err = "cannot allocate memory for journal"; 1796 if (bch_journal_read(c, &journal)) 1797 goto err; 1798 1799 pr_debug("btree_journal_read() done"); 1800 1801 err = "no journal entries found"; 1802 if (list_empty(&journal)) 1803 goto err; 1804 1805 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1806 1807 err = "IO error reading priorities"; 1808 for_each_cache(ca, c, i) 1809 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1810 1811 /* 1812 * If prio_read() fails it'll call cache_set_error and we'll 1813 * tear everything down right away, but if we perhaps checked 1814 * sooner we could avoid journal replay. 1815 */ 1816 1817 k = &j->btree_root; 1818 1819 err = "bad btree root"; 1820 if (__bch_btree_ptr_invalid(c, k)) 1821 goto err; 1822 1823 err = "error reading btree root"; 1824 c->root = bch_btree_node_get(c, NULL, k, 1825 j->btree_level, 1826 true, NULL); 1827 if (IS_ERR_OR_NULL(c->root)) 1828 goto err; 1829 1830 list_del_init(&c->root->list); 1831 rw_unlock(true, c->root); 1832 1833 err = uuid_read(c, j, &cl); 1834 if (err) 1835 goto err; 1836 1837 err = "error in recovery"; 1838 if (bch_btree_check(c)) 1839 goto err; 1840 1841 bch_journal_mark(c, &journal); 1842 bch_initial_gc_finish(c); 1843 pr_debug("btree_check() done"); 1844 1845 /* 1846 * bcache_journal_next() can't happen sooner, or 1847 * btree_gc_finish() will give spurious errors about last_gc > 1848 * gc_gen - this is a hack but oh well. 1849 */ 1850 bch_journal_next(&c->journal); 1851 1852 err = "error starting allocator thread"; 1853 for_each_cache(ca, c, i) 1854 if (bch_cache_allocator_start(ca)) 1855 goto err; 1856 1857 /* 1858 * First place it's safe to allocate: btree_check() and 1859 * btree_gc_finish() have to run before we have buckets to 1860 * allocate, and bch_bucket_alloc_set() might cause a journal 1861 * entry to be written so bcache_journal_next() has to be called 1862 * first. 1863 * 1864 * If the uuids were in the old format we have to rewrite them 1865 * before the next journal entry is written: 1866 */ 1867 if (j->version < BCACHE_JSET_VERSION_UUID) 1868 __uuid_write(c); 1869 1870 bch_journal_replay(c, &journal); 1871 } else { 1872 pr_notice("invalidating existing data"); 1873 1874 for_each_cache(ca, c, i) { 1875 unsigned int j; 1876 1877 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1878 2, SB_JOURNAL_BUCKETS); 1879 1880 for (j = 0; j < ca->sb.keys; j++) 1881 ca->sb.d[j] = ca->sb.first_bucket + j; 1882 } 1883 1884 bch_initial_gc_finish(c); 1885 1886 err = "error starting allocator thread"; 1887 for_each_cache(ca, c, i) 1888 if (bch_cache_allocator_start(ca)) 1889 goto err; 1890 1891 mutex_lock(&c->bucket_lock); 1892 for_each_cache(ca, c, i) 1893 bch_prio_write(ca); 1894 mutex_unlock(&c->bucket_lock); 1895 1896 err = "cannot allocate new UUID bucket"; 1897 if (__uuid_write(c)) 1898 goto err; 1899 1900 err = "cannot allocate new btree root"; 1901 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1902 if (IS_ERR_OR_NULL(c->root)) 1903 goto err; 1904 1905 mutex_lock(&c->root->write_lock); 1906 bkey_copy_key(&c->root->key, &MAX_KEY); 1907 bch_btree_node_write(c->root, &cl); 1908 mutex_unlock(&c->root->write_lock); 1909 1910 bch_btree_set_root(c->root); 1911 rw_unlock(true, c->root); 1912 1913 /* 1914 * We don't want to write the first journal entry until 1915 * everything is set up - fortunately journal entries won't be 1916 * written until the SET_CACHE_SYNC() here: 1917 */ 1918 SET_CACHE_SYNC(&c->sb, true); 1919 1920 bch_journal_next(&c->journal); 1921 bch_journal_meta(c, &cl); 1922 } 1923 1924 err = "error starting gc thread"; 1925 if (bch_gc_thread_start(c)) 1926 goto err; 1927 1928 closure_sync(&cl); 1929 c->sb.last_mount = (u32)ktime_get_real_seconds(); 1930 bcache_write_super(c); 1931 1932 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1933 bch_cached_dev_attach(dc, c, NULL); 1934 1935 flash_devs_run(c); 1936 1937 set_bit(CACHE_SET_RUNNING, &c->flags); 1938 return; 1939 err: 1940 closure_sync(&cl); 1941 /* XXX: test this, it's broken */ 1942 bch_cache_set_error(c, "%s", err); 1943 } 1944 1945 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 1946 { 1947 return ca->sb.block_size == c->sb.block_size && 1948 ca->sb.bucket_size == c->sb.bucket_size && 1949 ca->sb.nr_in_set == c->sb.nr_in_set; 1950 } 1951 1952 static const char *register_cache_set(struct cache *ca) 1953 { 1954 char buf[12]; 1955 const char *err = "cannot allocate memory"; 1956 struct cache_set *c; 1957 1958 list_for_each_entry(c, &bch_cache_sets, list) 1959 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 1960 if (c->cache[ca->sb.nr_this_dev]) 1961 return "duplicate cache set member"; 1962 1963 if (!can_attach_cache(ca, c)) 1964 return "cache sb does not match set"; 1965 1966 if (!CACHE_SYNC(&ca->sb)) 1967 SET_CACHE_SYNC(&c->sb, false); 1968 1969 goto found; 1970 } 1971 1972 c = bch_cache_set_alloc(&ca->sb); 1973 if (!c) 1974 return err; 1975 1976 err = "error creating kobject"; 1977 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 1978 kobject_add(&c->internal, &c->kobj, "internal")) 1979 goto err; 1980 1981 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 1982 goto err; 1983 1984 bch_debug_init_cache_set(c); 1985 1986 list_add(&c->list, &bch_cache_sets); 1987 found: 1988 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 1989 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 1990 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 1991 goto err; 1992 1993 if (ca->sb.seq > c->sb.seq) { 1994 c->sb.version = ca->sb.version; 1995 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 1996 c->sb.flags = ca->sb.flags; 1997 c->sb.seq = ca->sb.seq; 1998 pr_debug("set version = %llu", c->sb.version); 1999 } 2000 2001 kobject_get(&ca->kobj); 2002 ca->set = c; 2003 ca->set->cache[ca->sb.nr_this_dev] = ca; 2004 c->cache_by_alloc[c->caches_loaded++] = ca; 2005 2006 if (c->caches_loaded == c->sb.nr_in_set) 2007 run_cache_set(c); 2008 2009 return NULL; 2010 err: 2011 bch_cache_set_unregister(c); 2012 return err; 2013 } 2014 2015 /* Cache device */ 2016 2017 void bch_cache_release(struct kobject *kobj) 2018 { 2019 struct cache *ca = container_of(kobj, struct cache, kobj); 2020 unsigned int i; 2021 2022 if (ca->set) { 2023 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2024 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2025 } 2026 2027 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2028 kfree(ca->prio_buckets); 2029 vfree(ca->buckets); 2030 2031 free_heap(&ca->heap); 2032 free_fifo(&ca->free_inc); 2033 2034 for (i = 0; i < RESERVE_NR; i++) 2035 free_fifo(&ca->free[i]); 2036 2037 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2038 put_page(bio_first_page_all(&ca->sb_bio)); 2039 2040 if (!IS_ERR_OR_NULL(ca->bdev)) 2041 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2042 2043 kfree(ca); 2044 module_put(THIS_MODULE); 2045 } 2046 2047 static int cache_alloc(struct cache *ca) 2048 { 2049 size_t free; 2050 size_t btree_buckets; 2051 struct bucket *b; 2052 2053 __module_get(THIS_MODULE); 2054 kobject_init(&ca->kobj, &bch_cache_ktype); 2055 2056 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2057 2058 /* 2059 * when ca->sb.njournal_buckets is not zero, journal exists, 2060 * and in bch_journal_replay(), tree node may split, 2061 * so bucket of RESERVE_BTREE type is needed, 2062 * the worst situation is all journal buckets are valid journal, 2063 * and all the keys need to replay, 2064 * so the number of RESERVE_BTREE type buckets should be as much 2065 * as journal buckets 2066 */ 2067 btree_buckets = ca->sb.njournal_buckets ?: 8; 2068 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2069 2070 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) || 2071 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || 2072 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || 2073 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || 2074 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || 2075 !init_heap(&ca->heap, free << 3, GFP_KERNEL) || 2076 !(ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2077 ca->sb.nbuckets))) || 2078 !(ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2079 prio_buckets(ca), 2), 2080 GFP_KERNEL)) || 2081 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca))) 2082 return -ENOMEM; 2083 2084 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2085 2086 for_each_bucket(b, ca) 2087 atomic_set(&b->pin, 0); 2088 2089 return 0; 2090 } 2091 2092 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2093 struct block_device *bdev, struct cache *ca) 2094 { 2095 const char *err = NULL; /* must be set for any error case */ 2096 int ret = 0; 2097 2098 bdevname(bdev, ca->cache_dev_name); 2099 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2100 ca->bdev = bdev; 2101 ca->bdev->bd_holder = ca; 2102 2103 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2104 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2105 get_page(sb_page); 2106 2107 if (blk_queue_discard(bdev_get_queue(bdev))) 2108 ca->discard = CACHE_DISCARD(&ca->sb); 2109 2110 ret = cache_alloc(ca); 2111 if (ret != 0) { 2112 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2113 if (ret == -ENOMEM) 2114 err = "cache_alloc(): -ENOMEM"; 2115 else 2116 err = "cache_alloc(): unknown error"; 2117 goto err; 2118 } 2119 2120 if (kobject_add(&ca->kobj, 2121 &part_to_dev(bdev->bd_part)->kobj, 2122 "bcache")) { 2123 err = "error calling kobject_add"; 2124 ret = -ENOMEM; 2125 goto out; 2126 } 2127 2128 mutex_lock(&bch_register_lock); 2129 err = register_cache_set(ca); 2130 mutex_unlock(&bch_register_lock); 2131 2132 if (err) { 2133 ret = -ENODEV; 2134 goto out; 2135 } 2136 2137 pr_info("registered cache device %s", ca->cache_dev_name); 2138 2139 out: 2140 kobject_put(&ca->kobj); 2141 2142 err: 2143 if (err) 2144 pr_notice("error %s: %s", ca->cache_dev_name, err); 2145 2146 return ret; 2147 } 2148 2149 /* Global interfaces/init */ 2150 2151 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2152 const char *buffer, size_t size); 2153 2154 kobj_attribute_write(register, register_bcache); 2155 kobj_attribute_write(register_quiet, register_bcache); 2156 2157 static bool bch_is_open_backing(struct block_device *bdev) 2158 { 2159 struct cache_set *c, *tc; 2160 struct cached_dev *dc, *t; 2161 2162 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2163 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2164 if (dc->bdev == bdev) 2165 return true; 2166 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2167 if (dc->bdev == bdev) 2168 return true; 2169 return false; 2170 } 2171 2172 static bool bch_is_open_cache(struct block_device *bdev) 2173 { 2174 struct cache_set *c, *tc; 2175 struct cache *ca; 2176 unsigned int i; 2177 2178 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2179 for_each_cache(ca, c, i) 2180 if (ca->bdev == bdev) 2181 return true; 2182 return false; 2183 } 2184 2185 static bool bch_is_open(struct block_device *bdev) 2186 { 2187 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2188 } 2189 2190 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2191 const char *buffer, size_t size) 2192 { 2193 ssize_t ret = size; 2194 const char *err = "cannot allocate memory"; 2195 char *path = NULL; 2196 struct cache_sb *sb = NULL; 2197 struct block_device *bdev = NULL; 2198 struct page *sb_page = NULL; 2199 2200 if (!try_module_get(THIS_MODULE)) 2201 return -EBUSY; 2202 2203 path = kstrndup(buffer, size, GFP_KERNEL); 2204 if (!path) 2205 goto err; 2206 2207 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); 2208 if (!sb) 2209 goto err; 2210 2211 err = "failed to open device"; 2212 bdev = blkdev_get_by_path(strim(path), 2213 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2214 sb); 2215 if (IS_ERR(bdev)) { 2216 if (bdev == ERR_PTR(-EBUSY)) { 2217 bdev = lookup_bdev(strim(path)); 2218 mutex_lock(&bch_register_lock); 2219 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2220 err = "device already registered"; 2221 else 2222 err = "device busy"; 2223 mutex_unlock(&bch_register_lock); 2224 if (!IS_ERR(bdev)) 2225 bdput(bdev); 2226 if (attr == &ksysfs_register_quiet) 2227 goto out; 2228 } 2229 goto err; 2230 } 2231 2232 err = "failed to set blocksize"; 2233 if (set_blocksize(bdev, 4096)) 2234 goto err_close; 2235 2236 err = read_super(sb, bdev, &sb_page); 2237 if (err) 2238 goto err_close; 2239 2240 err = "failed to register device"; 2241 if (SB_IS_BDEV(sb)) { 2242 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2243 2244 if (!dc) 2245 goto err_close; 2246 2247 mutex_lock(&bch_register_lock); 2248 register_bdev(sb, sb_page, bdev, dc); 2249 mutex_unlock(&bch_register_lock); 2250 } else { 2251 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2252 2253 if (!ca) 2254 goto err_close; 2255 2256 if (register_cache(sb, sb_page, bdev, ca) != 0) 2257 goto err; 2258 } 2259 out: 2260 if (sb_page) 2261 put_page(sb_page); 2262 kfree(sb); 2263 kfree(path); 2264 module_put(THIS_MODULE); 2265 return ret; 2266 2267 err_close: 2268 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2269 err: 2270 pr_info("error %s: %s", path, err); 2271 ret = -EINVAL; 2272 goto out; 2273 } 2274 2275 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2276 { 2277 if (code == SYS_DOWN || 2278 code == SYS_HALT || 2279 code == SYS_POWER_OFF) { 2280 DEFINE_WAIT(wait); 2281 unsigned long start = jiffies; 2282 bool stopped = false; 2283 2284 struct cache_set *c, *tc; 2285 struct cached_dev *dc, *tdc; 2286 2287 mutex_lock(&bch_register_lock); 2288 2289 if (list_empty(&bch_cache_sets) && 2290 list_empty(&uncached_devices)) 2291 goto out; 2292 2293 pr_info("Stopping all devices:"); 2294 2295 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2296 bch_cache_set_stop(c); 2297 2298 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2299 bcache_device_stop(&dc->disk); 2300 2301 /* What's a condition variable? */ 2302 while (1) { 2303 long timeout = start + 2 * HZ - jiffies; 2304 2305 stopped = list_empty(&bch_cache_sets) && 2306 list_empty(&uncached_devices); 2307 2308 if (timeout < 0 || stopped) 2309 break; 2310 2311 prepare_to_wait(&unregister_wait, &wait, 2312 TASK_UNINTERRUPTIBLE); 2313 2314 mutex_unlock(&bch_register_lock); 2315 schedule_timeout(timeout); 2316 mutex_lock(&bch_register_lock); 2317 } 2318 2319 finish_wait(&unregister_wait, &wait); 2320 2321 if (stopped) 2322 pr_info("All devices stopped"); 2323 else 2324 pr_notice("Timeout waiting for devices to be closed"); 2325 out: 2326 mutex_unlock(&bch_register_lock); 2327 } 2328 2329 return NOTIFY_DONE; 2330 } 2331 2332 static struct notifier_block reboot = { 2333 .notifier_call = bcache_reboot, 2334 .priority = INT_MAX, /* before any real devices */ 2335 }; 2336 2337 static void bcache_exit(void) 2338 { 2339 bch_debug_exit(); 2340 bch_request_exit(); 2341 if (bcache_kobj) 2342 kobject_put(bcache_kobj); 2343 if (bcache_wq) 2344 destroy_workqueue(bcache_wq); 2345 if (bch_journal_wq) 2346 destroy_workqueue(bch_journal_wq); 2347 2348 if (bcache_major) 2349 unregister_blkdev(bcache_major, "bcache"); 2350 unregister_reboot_notifier(&reboot); 2351 mutex_destroy(&bch_register_lock); 2352 } 2353 2354 static int __init bcache_init(void) 2355 { 2356 static const struct attribute *files[] = { 2357 &ksysfs_register.attr, 2358 &ksysfs_register_quiet.attr, 2359 NULL 2360 }; 2361 2362 mutex_init(&bch_register_lock); 2363 init_waitqueue_head(&unregister_wait); 2364 register_reboot_notifier(&reboot); 2365 2366 bcache_major = register_blkdev(0, "bcache"); 2367 if (bcache_major < 0) { 2368 unregister_reboot_notifier(&reboot); 2369 mutex_destroy(&bch_register_lock); 2370 return bcache_major; 2371 } 2372 2373 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); 2374 if (!bcache_wq) 2375 goto err; 2376 2377 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); 2378 if (!bch_journal_wq) 2379 goto err; 2380 2381 bcache_kobj = kobject_create_and_add("bcache", fs_kobj); 2382 if (!bcache_kobj) 2383 goto err; 2384 2385 if (bch_request_init() || 2386 sysfs_create_files(bcache_kobj, files)) 2387 goto err; 2388 2389 bch_debug_init(bcache_kobj); 2390 closure_debug_init(); 2391 2392 return 0; 2393 err: 2394 bcache_exit(); 2395 return -ENOMEM; 2396 } 2397 2398 module_exit(bcache_exit); 2399 module_init(bcache_init); 2400