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 unsigned int bch_cutoff_writeback; 29 unsigned int bch_cutoff_writeback_sync; 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 bool bcache_is_reboot; 44 LIST_HEAD(bch_cache_sets); 45 static LIST_HEAD(uncached_devices); 46 47 static int bcache_major; 48 static DEFINE_IDA(bcache_device_idx); 49 static wait_queue_head_t unregister_wait; 50 struct workqueue_struct *bcache_wq; 51 struct workqueue_struct *bch_journal_wq; 52 53 54 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) 55 /* limitation of partitions number on single bcache device */ 56 #define BCACHE_MINORS 128 57 /* limitation of bcache devices number on single system */ 58 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) 59 60 /* Superblock */ 61 62 static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 63 struct page **res) 64 { 65 const char *err; 66 struct cache_sb *s; 67 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); 68 unsigned int i; 69 70 if (!bh) 71 return "IO error"; 72 73 s = (struct cache_sb *) bh->b_data; 74 75 sb->offset = le64_to_cpu(s->offset); 76 sb->version = le64_to_cpu(s->version); 77 78 memcpy(sb->magic, s->magic, 16); 79 memcpy(sb->uuid, s->uuid, 16); 80 memcpy(sb->set_uuid, s->set_uuid, 16); 81 memcpy(sb->label, s->label, SB_LABEL_SIZE); 82 83 sb->flags = le64_to_cpu(s->flags); 84 sb->seq = le64_to_cpu(s->seq); 85 sb->last_mount = le32_to_cpu(s->last_mount); 86 sb->first_bucket = le16_to_cpu(s->first_bucket); 87 sb->keys = le16_to_cpu(s->keys); 88 89 for (i = 0; i < SB_JOURNAL_BUCKETS; i++) 90 sb->d[i] = le64_to_cpu(s->d[i]); 91 92 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", 93 sb->version, sb->flags, sb->seq, sb->keys); 94 95 err = "Not a bcache superblock"; 96 if (sb->offset != SB_SECTOR) 97 goto err; 98 99 if (memcmp(sb->magic, bcache_magic, 16)) 100 goto err; 101 102 err = "Too many journal buckets"; 103 if (sb->keys > SB_JOURNAL_BUCKETS) 104 goto err; 105 106 err = "Bad checksum"; 107 if (s->csum != csum_set(s)) 108 goto err; 109 110 err = "Bad UUID"; 111 if (bch_is_zero(sb->uuid, 16)) 112 goto err; 113 114 sb->block_size = le16_to_cpu(s->block_size); 115 116 err = "Superblock block size smaller than device block size"; 117 if (sb->block_size << 9 < bdev_logical_block_size(bdev)) 118 goto err; 119 120 switch (sb->version) { 121 case BCACHE_SB_VERSION_BDEV: 122 sb->data_offset = BDEV_DATA_START_DEFAULT; 123 break; 124 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: 125 sb->data_offset = le64_to_cpu(s->data_offset); 126 127 err = "Bad data offset"; 128 if (sb->data_offset < BDEV_DATA_START_DEFAULT) 129 goto err; 130 131 break; 132 case BCACHE_SB_VERSION_CDEV: 133 case BCACHE_SB_VERSION_CDEV_WITH_UUID: 134 sb->nbuckets = le64_to_cpu(s->nbuckets); 135 sb->bucket_size = le16_to_cpu(s->bucket_size); 136 137 sb->nr_in_set = le16_to_cpu(s->nr_in_set); 138 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 139 140 err = "Too many buckets"; 141 if (sb->nbuckets > LONG_MAX) 142 goto err; 143 144 err = "Not enough buckets"; 145 if (sb->nbuckets < 1 << 7) 146 goto err; 147 148 err = "Bad block/bucket size"; 149 if (!is_power_of_2(sb->block_size) || 150 sb->block_size > PAGE_SECTORS || 151 !is_power_of_2(sb->bucket_size) || 152 sb->bucket_size < PAGE_SECTORS) 153 goto err; 154 155 err = "Invalid superblock: device too small"; 156 if (get_capacity(bdev->bd_disk) < 157 sb->bucket_size * sb->nbuckets) 158 goto err; 159 160 err = "Bad UUID"; 161 if (bch_is_zero(sb->set_uuid, 16)) 162 goto err; 163 164 err = "Bad cache device number in set"; 165 if (!sb->nr_in_set || 166 sb->nr_in_set <= sb->nr_this_dev || 167 sb->nr_in_set > MAX_CACHES_PER_SET) 168 goto err; 169 170 err = "Journal buckets not sequential"; 171 for (i = 0; i < sb->keys; i++) 172 if (sb->d[i] != sb->first_bucket + i) 173 goto err; 174 175 err = "Too many journal buckets"; 176 if (sb->first_bucket + sb->keys > sb->nbuckets) 177 goto err; 178 179 err = "Invalid superblock: first bucket comes before end of super"; 180 if (sb->first_bucket * sb->bucket_size < 16) 181 goto err; 182 183 break; 184 default: 185 err = "Unsupported superblock version"; 186 goto err; 187 } 188 189 sb->last_mount = (u32)ktime_get_real_seconds(); 190 err = NULL; 191 192 get_page(bh->b_page); 193 *res = bh->b_page; 194 err: 195 put_bh(bh); 196 return err; 197 } 198 199 static void write_bdev_super_endio(struct bio *bio) 200 { 201 struct cached_dev *dc = bio->bi_private; 202 203 if (bio->bi_status) 204 bch_count_backing_io_errors(dc, bio); 205 206 closure_put(&dc->sb_write); 207 } 208 209 static void __write_super(struct cache_sb *sb, struct bio *bio) 210 { 211 struct cache_sb *out = page_address(bio_first_page_all(bio)); 212 unsigned int i; 213 214 bio->bi_iter.bi_sector = SB_SECTOR; 215 bio->bi_iter.bi_size = SB_SIZE; 216 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 217 bch_bio_map(bio, NULL); 218 219 out->offset = cpu_to_le64(sb->offset); 220 out->version = cpu_to_le64(sb->version); 221 222 memcpy(out->uuid, sb->uuid, 16); 223 memcpy(out->set_uuid, sb->set_uuid, 16); 224 memcpy(out->label, sb->label, SB_LABEL_SIZE); 225 226 out->flags = cpu_to_le64(sb->flags); 227 out->seq = cpu_to_le64(sb->seq); 228 229 out->last_mount = cpu_to_le32(sb->last_mount); 230 out->first_bucket = cpu_to_le16(sb->first_bucket); 231 out->keys = cpu_to_le16(sb->keys); 232 233 for (i = 0; i < sb->keys; i++) 234 out->d[i] = cpu_to_le64(sb->d[i]); 235 236 out->csum = csum_set(out); 237 238 pr_debug("ver %llu, flags %llu, seq %llu", 239 sb->version, sb->flags, sb->seq); 240 241 submit_bio(bio); 242 } 243 244 static void bch_write_bdev_super_unlock(struct closure *cl) 245 { 246 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); 247 248 up(&dc->sb_write_mutex); 249 } 250 251 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 252 { 253 struct closure *cl = &dc->sb_write; 254 struct bio *bio = &dc->sb_bio; 255 256 down(&dc->sb_write_mutex); 257 closure_init(cl, parent); 258 259 bio_reset(bio); 260 bio_set_dev(bio, dc->bdev); 261 bio->bi_end_io = write_bdev_super_endio; 262 bio->bi_private = dc; 263 264 closure_get(cl); 265 /* I/O request sent to backing device */ 266 __write_super(&dc->sb, bio); 267 268 closure_return_with_destructor(cl, bch_write_bdev_super_unlock); 269 } 270 271 static void write_super_endio(struct bio *bio) 272 { 273 struct cache *ca = bio->bi_private; 274 275 /* is_read = 0 */ 276 bch_count_io_errors(ca, bio->bi_status, 0, 277 "writing superblock"); 278 closure_put(&ca->set->sb_write); 279 } 280 281 static void bcache_write_super_unlock(struct closure *cl) 282 { 283 struct cache_set *c = container_of(cl, struct cache_set, sb_write); 284 285 up(&c->sb_write_mutex); 286 } 287 288 void bcache_write_super(struct cache_set *c) 289 { 290 struct closure *cl = &c->sb_write; 291 struct cache *ca; 292 unsigned int i; 293 294 down(&c->sb_write_mutex); 295 closure_init(cl, &c->cl); 296 297 c->sb.seq++; 298 299 for_each_cache(ca, c, i) { 300 struct bio *bio = &ca->sb_bio; 301 302 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; 303 ca->sb.seq = c->sb.seq; 304 ca->sb.last_mount = c->sb.last_mount; 305 306 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); 307 308 bio_reset(bio); 309 bio_set_dev(bio, ca->bdev); 310 bio->bi_end_io = write_super_endio; 311 bio->bi_private = ca; 312 313 closure_get(cl); 314 __write_super(&ca->sb, bio); 315 } 316 317 closure_return_with_destructor(cl, bcache_write_super_unlock); 318 } 319 320 /* UUID io */ 321 322 static void uuid_endio(struct bio *bio) 323 { 324 struct closure *cl = bio->bi_private; 325 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 326 327 cache_set_err_on(bio->bi_status, c, "accessing uuids"); 328 bch_bbio_free(bio, c); 329 closure_put(cl); 330 } 331 332 static void uuid_io_unlock(struct closure *cl) 333 { 334 struct cache_set *c = container_of(cl, struct cache_set, uuid_write); 335 336 up(&c->uuid_write_mutex); 337 } 338 339 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags, 340 struct bkey *k, struct closure *parent) 341 { 342 struct closure *cl = &c->uuid_write; 343 struct uuid_entry *u; 344 unsigned int i; 345 char buf[80]; 346 347 BUG_ON(!parent); 348 down(&c->uuid_write_mutex); 349 closure_init(cl, parent); 350 351 for (i = 0; i < KEY_PTRS(k); i++) { 352 struct bio *bio = bch_bbio_alloc(c); 353 354 bio->bi_opf = REQ_SYNC | REQ_META | op_flags; 355 bio->bi_iter.bi_size = KEY_SIZE(k) << 9; 356 357 bio->bi_end_io = uuid_endio; 358 bio->bi_private = cl; 359 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 360 bch_bio_map(bio, c->uuids); 361 362 bch_submit_bbio(bio, c, k, i); 363 364 if (op != REQ_OP_WRITE) 365 break; 366 } 367 368 bch_extent_to_text(buf, sizeof(buf), k); 369 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf); 370 371 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) 372 if (!bch_is_zero(u->uuid, 16)) 373 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", 374 u - c->uuids, u->uuid, u->label, 375 u->first_reg, u->last_reg, u->invalidated); 376 377 closure_return_with_destructor(cl, uuid_io_unlock); 378 } 379 380 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) 381 { 382 struct bkey *k = &j->uuid_bucket; 383 384 if (__bch_btree_ptr_invalid(c, k)) 385 return "bad uuid pointer"; 386 387 bkey_copy(&c->uuid_bucket, k); 388 uuid_io(c, REQ_OP_READ, 0, k, cl); 389 390 if (j->version < BCACHE_JSET_VERSION_UUIDv1) { 391 struct uuid_entry_v0 *u0 = (void *) c->uuids; 392 struct uuid_entry *u1 = (void *) c->uuids; 393 int i; 394 395 closure_sync(cl); 396 397 /* 398 * Since the new uuid entry is bigger than the old, we have to 399 * convert starting at the highest memory address and work down 400 * in order to do it in place 401 */ 402 403 for (i = c->nr_uuids - 1; 404 i >= 0; 405 --i) { 406 memcpy(u1[i].uuid, u0[i].uuid, 16); 407 memcpy(u1[i].label, u0[i].label, 32); 408 409 u1[i].first_reg = u0[i].first_reg; 410 u1[i].last_reg = u0[i].last_reg; 411 u1[i].invalidated = u0[i].invalidated; 412 413 u1[i].flags = 0; 414 u1[i].sectors = 0; 415 } 416 } 417 418 return NULL; 419 } 420 421 static int __uuid_write(struct cache_set *c) 422 { 423 BKEY_PADDED(key) k; 424 struct closure cl; 425 struct cache *ca; 426 427 closure_init_stack(&cl); 428 lockdep_assert_held(&bch_register_lock); 429 430 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) 431 return 1; 432 433 SET_KEY_SIZE(&k.key, c->sb.bucket_size); 434 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); 435 closure_sync(&cl); 436 437 /* Only one bucket used for uuid write */ 438 ca = PTR_CACHE(c, &k.key, 0); 439 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written); 440 441 bkey_copy(&c->uuid_bucket, &k.key); 442 bkey_put(c, &k.key); 443 return 0; 444 } 445 446 int bch_uuid_write(struct cache_set *c) 447 { 448 int ret = __uuid_write(c); 449 450 if (!ret) 451 bch_journal_meta(c, NULL); 452 453 return ret; 454 } 455 456 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) 457 { 458 struct uuid_entry *u; 459 460 for (u = c->uuids; 461 u < c->uuids + c->nr_uuids; u++) 462 if (!memcmp(u->uuid, uuid, 16)) 463 return u; 464 465 return NULL; 466 } 467 468 static struct uuid_entry *uuid_find_empty(struct cache_set *c) 469 { 470 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 471 472 return uuid_find(c, zero_uuid); 473 } 474 475 /* 476 * Bucket priorities/gens: 477 * 478 * For each bucket, we store on disk its 479 * 8 bit gen 480 * 16 bit priority 481 * 482 * See alloc.c for an explanation of the gen. The priority is used to implement 483 * lru (and in the future other) cache replacement policies; for most purposes 484 * it's just an opaque integer. 485 * 486 * The gens and the priorities don't have a whole lot to do with each other, and 487 * it's actually the gens that must be written out at specific times - it's no 488 * big deal if the priorities don't get written, if we lose them we just reuse 489 * buckets in suboptimal order. 490 * 491 * On disk they're stored in a packed array, and in as many buckets are required 492 * to fit them all. The buckets we use to store them form a list; the journal 493 * header points to the first bucket, the first bucket points to the second 494 * bucket, et cetera. 495 * 496 * This code is used by the allocation code; periodically (whenever it runs out 497 * of buckets to allocate from) the allocation code will invalidate some 498 * buckets, but it can't use those buckets until their new gens are safely on 499 * disk. 500 */ 501 502 static void prio_endio(struct bio *bio) 503 { 504 struct cache *ca = bio->bi_private; 505 506 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); 507 bch_bbio_free(bio, ca->set); 508 closure_put(&ca->prio); 509 } 510 511 static void prio_io(struct cache *ca, uint64_t bucket, int op, 512 unsigned long op_flags) 513 { 514 struct closure *cl = &ca->prio; 515 struct bio *bio = bch_bbio_alloc(ca->set); 516 517 closure_init_stack(cl); 518 519 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; 520 bio_set_dev(bio, ca->bdev); 521 bio->bi_iter.bi_size = bucket_bytes(ca); 522 523 bio->bi_end_io = prio_endio; 524 bio->bi_private = ca; 525 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); 526 bch_bio_map(bio, ca->disk_buckets); 527 528 closure_bio_submit(ca->set, bio, &ca->prio); 529 closure_sync(cl); 530 } 531 532 void bch_prio_write(struct cache *ca) 533 { 534 int i; 535 struct bucket *b; 536 struct closure cl; 537 538 closure_init_stack(&cl); 539 540 lockdep_assert_held(&ca->set->bucket_lock); 541 542 ca->disk_buckets->seq++; 543 544 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), 545 &ca->meta_sectors_written); 546 547 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), 548 // fifo_used(&ca->free_inc), fifo_used(&ca->unused)); 549 550 for (i = prio_buckets(ca) - 1; i >= 0; --i) { 551 long bucket; 552 struct prio_set *p = ca->disk_buckets; 553 struct bucket_disk *d = p->data; 554 struct bucket_disk *end = d + prios_per_bucket(ca); 555 556 for (b = ca->buckets + i * prios_per_bucket(ca); 557 b < ca->buckets + ca->sb.nbuckets && d < end; 558 b++, d++) { 559 d->prio = cpu_to_le16(b->prio); 560 d->gen = b->gen; 561 } 562 563 p->next_bucket = ca->prio_buckets[i + 1]; 564 p->magic = pset_magic(&ca->sb); 565 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); 566 567 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); 568 BUG_ON(bucket == -1); 569 570 mutex_unlock(&ca->set->bucket_lock); 571 prio_io(ca, bucket, REQ_OP_WRITE, 0); 572 mutex_lock(&ca->set->bucket_lock); 573 574 ca->prio_buckets[i] = bucket; 575 atomic_dec_bug(&ca->buckets[bucket].pin); 576 } 577 578 mutex_unlock(&ca->set->bucket_lock); 579 580 bch_journal_meta(ca->set, &cl); 581 closure_sync(&cl); 582 583 mutex_lock(&ca->set->bucket_lock); 584 585 /* 586 * Don't want the old priorities to get garbage collected until after we 587 * finish writing the new ones, and they're journalled 588 */ 589 for (i = 0; i < prio_buckets(ca); i++) { 590 if (ca->prio_last_buckets[i]) 591 __bch_bucket_free(ca, 592 &ca->buckets[ca->prio_last_buckets[i]]); 593 594 ca->prio_last_buckets[i] = ca->prio_buckets[i]; 595 } 596 } 597 598 static void prio_read(struct cache *ca, uint64_t bucket) 599 { 600 struct prio_set *p = ca->disk_buckets; 601 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; 602 struct bucket *b; 603 unsigned int bucket_nr = 0; 604 605 for (b = ca->buckets; 606 b < ca->buckets + ca->sb.nbuckets; 607 b++, d++) { 608 if (d == end) { 609 ca->prio_buckets[bucket_nr] = bucket; 610 ca->prio_last_buckets[bucket_nr] = bucket; 611 bucket_nr++; 612 613 prio_io(ca, bucket, REQ_OP_READ, 0); 614 615 if (p->csum != 616 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) 617 pr_warn("bad csum reading priorities"); 618 619 if (p->magic != pset_magic(&ca->sb)) 620 pr_warn("bad magic reading priorities"); 621 622 bucket = p->next_bucket; 623 d = p->data; 624 } 625 626 b->prio = le16_to_cpu(d->prio); 627 b->gen = b->last_gc = d->gen; 628 } 629 } 630 631 /* Bcache device */ 632 633 static int open_dev(struct block_device *b, fmode_t mode) 634 { 635 struct bcache_device *d = b->bd_disk->private_data; 636 637 if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) 638 return -ENXIO; 639 640 closure_get(&d->cl); 641 return 0; 642 } 643 644 static void release_dev(struct gendisk *b, fmode_t mode) 645 { 646 struct bcache_device *d = b->private_data; 647 648 closure_put(&d->cl); 649 } 650 651 static int ioctl_dev(struct block_device *b, fmode_t mode, 652 unsigned int cmd, unsigned long arg) 653 { 654 struct bcache_device *d = b->bd_disk->private_data; 655 656 return d->ioctl(d, mode, cmd, arg); 657 } 658 659 static const struct block_device_operations bcache_ops = { 660 .open = open_dev, 661 .release = release_dev, 662 .ioctl = ioctl_dev, 663 .owner = THIS_MODULE, 664 }; 665 666 void bcache_device_stop(struct bcache_device *d) 667 { 668 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) 669 /* 670 * closure_fn set to 671 * - cached device: cached_dev_flush() 672 * - flash dev: flash_dev_flush() 673 */ 674 closure_queue(&d->cl); 675 } 676 677 static void bcache_device_unlink(struct bcache_device *d) 678 { 679 lockdep_assert_held(&bch_register_lock); 680 681 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { 682 unsigned int i; 683 struct cache *ca; 684 685 sysfs_remove_link(&d->c->kobj, d->name); 686 sysfs_remove_link(&d->kobj, "cache"); 687 688 for_each_cache(ca, d->c, i) 689 bd_unlink_disk_holder(ca->bdev, d->disk); 690 } 691 } 692 693 static void bcache_device_link(struct bcache_device *d, struct cache_set *c, 694 const char *name) 695 { 696 unsigned int i; 697 struct cache *ca; 698 int ret; 699 700 for_each_cache(ca, d->c, i) 701 bd_link_disk_holder(ca->bdev, d->disk); 702 703 snprintf(d->name, BCACHEDEVNAME_SIZE, 704 "%s%u", name, d->id); 705 706 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache"); 707 if (ret < 0) 708 pr_err("Couldn't create device -> cache set symlink"); 709 710 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name); 711 if (ret < 0) 712 pr_err("Couldn't create cache set -> device symlink"); 713 714 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); 715 } 716 717 static void bcache_device_detach(struct bcache_device *d) 718 { 719 lockdep_assert_held(&bch_register_lock); 720 721 atomic_dec(&d->c->attached_dev_nr); 722 723 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { 724 struct uuid_entry *u = d->c->uuids + d->id; 725 726 SET_UUID_FLASH_ONLY(u, 0); 727 memcpy(u->uuid, invalid_uuid, 16); 728 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 729 bch_uuid_write(d->c); 730 } 731 732 bcache_device_unlink(d); 733 734 d->c->devices[d->id] = NULL; 735 closure_put(&d->c->caching); 736 d->c = NULL; 737 } 738 739 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, 740 unsigned int id) 741 { 742 d->id = id; 743 d->c = c; 744 c->devices[id] = d; 745 746 if (id >= c->devices_max_used) 747 c->devices_max_used = id + 1; 748 749 closure_get(&c->caching); 750 } 751 752 static inline int first_minor_to_idx(int first_minor) 753 { 754 return (first_minor/BCACHE_MINORS); 755 } 756 757 static inline int idx_to_first_minor(int idx) 758 { 759 return (idx * BCACHE_MINORS); 760 } 761 762 static void bcache_device_free(struct bcache_device *d) 763 { 764 lockdep_assert_held(&bch_register_lock); 765 766 pr_info("%s stopped", d->disk->disk_name); 767 768 if (d->c) 769 bcache_device_detach(d); 770 if (d->disk && d->disk->flags & GENHD_FL_UP) 771 del_gendisk(d->disk); 772 if (d->disk && d->disk->queue) 773 blk_cleanup_queue(d->disk->queue); 774 if (d->disk) { 775 ida_simple_remove(&bcache_device_idx, 776 first_minor_to_idx(d->disk->first_minor)); 777 put_disk(d->disk); 778 } 779 780 bioset_exit(&d->bio_split); 781 kvfree(d->full_dirty_stripes); 782 kvfree(d->stripe_sectors_dirty); 783 784 closure_debug_destroy(&d->cl); 785 } 786 787 static int bcache_device_init(struct bcache_device *d, unsigned int block_size, 788 sector_t sectors) 789 { 790 struct request_queue *q; 791 const size_t max_stripes = min_t(size_t, INT_MAX, 792 SIZE_MAX / sizeof(atomic_t)); 793 size_t n; 794 int idx; 795 796 if (!d->stripe_size) 797 d->stripe_size = 1 << 31; 798 799 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); 800 801 if (!d->nr_stripes || d->nr_stripes > max_stripes) { 802 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", 803 (unsigned int)d->nr_stripes); 804 return -ENOMEM; 805 } 806 807 n = d->nr_stripes * sizeof(atomic_t); 808 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); 809 if (!d->stripe_sectors_dirty) 810 return -ENOMEM; 811 812 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); 813 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); 814 if (!d->full_dirty_stripes) 815 return -ENOMEM; 816 817 idx = ida_simple_get(&bcache_device_idx, 0, 818 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); 819 if (idx < 0) 820 return idx; 821 822 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), 823 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) 824 goto err; 825 826 d->disk = alloc_disk(BCACHE_MINORS); 827 if (!d->disk) 828 goto err; 829 830 set_capacity(d->disk, sectors); 831 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); 832 833 d->disk->major = bcache_major; 834 d->disk->first_minor = idx_to_first_minor(idx); 835 d->disk->fops = &bcache_ops; 836 d->disk->private_data = d; 837 838 q = blk_alloc_queue(GFP_KERNEL); 839 if (!q) 840 return -ENOMEM; 841 842 blk_queue_make_request(q, NULL); 843 d->disk->queue = q; 844 q->queuedata = d; 845 q->backing_dev_info->congested_data = d; 846 q->limits.max_hw_sectors = UINT_MAX; 847 q->limits.max_sectors = UINT_MAX; 848 q->limits.max_segment_size = UINT_MAX; 849 q->limits.max_segments = BIO_MAX_PAGES; 850 blk_queue_max_discard_sectors(q, UINT_MAX); 851 q->limits.discard_granularity = 512; 852 q->limits.io_min = block_size; 853 q->limits.logical_block_size = block_size; 854 q->limits.physical_block_size = block_size; 855 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); 856 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); 857 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); 858 859 blk_queue_write_cache(q, true, true); 860 861 return 0; 862 863 err: 864 ida_simple_remove(&bcache_device_idx, idx); 865 return -ENOMEM; 866 867 } 868 869 /* Cached device */ 870 871 static void calc_cached_dev_sectors(struct cache_set *c) 872 { 873 uint64_t sectors = 0; 874 struct cached_dev *dc; 875 876 list_for_each_entry(dc, &c->cached_devs, list) 877 sectors += bdev_sectors(dc->bdev); 878 879 c->cached_dev_sectors = sectors; 880 } 881 882 #define BACKING_DEV_OFFLINE_TIMEOUT 5 883 static int cached_dev_status_update(void *arg) 884 { 885 struct cached_dev *dc = arg; 886 struct request_queue *q; 887 888 /* 889 * If this delayed worker is stopping outside, directly quit here. 890 * dc->io_disable might be set via sysfs interface, so check it 891 * here too. 892 */ 893 while (!kthread_should_stop() && !dc->io_disable) { 894 q = bdev_get_queue(dc->bdev); 895 if (blk_queue_dying(q)) 896 dc->offline_seconds++; 897 else 898 dc->offline_seconds = 0; 899 900 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { 901 pr_err("%s: device offline for %d seconds", 902 dc->backing_dev_name, 903 BACKING_DEV_OFFLINE_TIMEOUT); 904 pr_err("%s: disable I/O request due to backing " 905 "device offline", dc->disk.name); 906 dc->io_disable = true; 907 /* let others know earlier that io_disable is true */ 908 smp_mb(); 909 bcache_device_stop(&dc->disk); 910 break; 911 } 912 schedule_timeout_interruptible(HZ); 913 } 914 915 wait_for_kthread_stop(); 916 return 0; 917 } 918 919 920 int bch_cached_dev_run(struct cached_dev *dc) 921 { 922 struct bcache_device *d = &dc->disk; 923 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL); 924 char *env[] = { 925 "DRIVER=bcache", 926 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), 927 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""), 928 NULL, 929 }; 930 931 if (dc->io_disable) { 932 pr_err("I/O disabled on cached dev %s", 933 dc->backing_dev_name); 934 return -EIO; 935 } 936 937 if (atomic_xchg(&dc->running, 1)) { 938 kfree(env[1]); 939 kfree(env[2]); 940 kfree(buf); 941 pr_info("cached dev %s is running already", 942 dc->backing_dev_name); 943 return -EBUSY; 944 } 945 946 if (!d->c && 947 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { 948 struct closure cl; 949 950 closure_init_stack(&cl); 951 952 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); 953 bch_write_bdev_super(dc, &cl); 954 closure_sync(&cl); 955 } 956 957 add_disk(d->disk); 958 bd_link_disk_holder(dc->bdev, dc->disk.disk); 959 /* 960 * won't show up in the uevent file, use udevadm monitor -e instead 961 * only class / kset properties are persistent 962 */ 963 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); 964 kfree(env[1]); 965 kfree(env[2]); 966 kfree(buf); 967 968 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || 969 sysfs_create_link(&disk_to_dev(d->disk)->kobj, 970 &d->kobj, "bcache")) { 971 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks"); 972 return -ENOMEM; 973 } 974 975 dc->status_update_thread = kthread_run(cached_dev_status_update, 976 dc, "bcache_status_update"); 977 if (IS_ERR(dc->status_update_thread)) { 978 pr_warn("failed to create bcache_status_update kthread, " 979 "continue to run without monitoring backing " 980 "device status"); 981 } 982 983 return 0; 984 } 985 986 /* 987 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed 988 * work dc->writeback_rate_update is running. Wait until the routine 989 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to 990 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out 991 * seconds, give up waiting here and continue to cancel it too. 992 */ 993 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) 994 { 995 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; 996 997 do { 998 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, 999 &dc->disk.flags)) 1000 break; 1001 time_out--; 1002 schedule_timeout_interruptible(1); 1003 } while (time_out > 0); 1004 1005 if (time_out == 0) 1006 pr_warn("give up waiting for dc->writeback_write_update to quit"); 1007 1008 cancel_delayed_work_sync(&dc->writeback_rate_update); 1009 } 1010 1011 static void cached_dev_detach_finish(struct work_struct *w) 1012 { 1013 struct cached_dev *dc = container_of(w, struct cached_dev, detach); 1014 struct closure cl; 1015 1016 closure_init_stack(&cl); 1017 1018 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); 1019 BUG_ON(refcount_read(&dc->count)); 1020 1021 1022 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1023 cancel_writeback_rate_update_dwork(dc); 1024 1025 if (!IS_ERR_OR_NULL(dc->writeback_thread)) { 1026 kthread_stop(dc->writeback_thread); 1027 dc->writeback_thread = NULL; 1028 } 1029 1030 memset(&dc->sb.set_uuid, 0, 16); 1031 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); 1032 1033 bch_write_bdev_super(dc, &cl); 1034 closure_sync(&cl); 1035 1036 mutex_lock(&bch_register_lock); 1037 1038 calc_cached_dev_sectors(dc->disk.c); 1039 bcache_device_detach(&dc->disk); 1040 list_move(&dc->list, &uncached_devices); 1041 1042 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); 1043 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); 1044 1045 mutex_unlock(&bch_register_lock); 1046 1047 pr_info("Caching disabled for %s", dc->backing_dev_name); 1048 1049 /* Drop ref we took in cached_dev_detach() */ 1050 closure_put(&dc->disk.cl); 1051 } 1052 1053 void bch_cached_dev_detach(struct cached_dev *dc) 1054 { 1055 lockdep_assert_held(&bch_register_lock); 1056 1057 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1058 return; 1059 1060 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) 1061 return; 1062 1063 /* 1064 * Block the device from being closed and freed until we're finished 1065 * detaching 1066 */ 1067 closure_get(&dc->disk.cl); 1068 1069 bch_writeback_queue(dc); 1070 1071 cached_dev_put(dc); 1072 } 1073 1074 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, 1075 uint8_t *set_uuid) 1076 { 1077 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); 1078 struct uuid_entry *u; 1079 struct cached_dev *exist_dc, *t; 1080 int ret = 0; 1081 1082 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || 1083 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) 1084 return -ENOENT; 1085 1086 if (dc->disk.c) { 1087 pr_err("Can't attach %s: already attached", 1088 dc->backing_dev_name); 1089 return -EINVAL; 1090 } 1091 1092 if (test_bit(CACHE_SET_STOPPING, &c->flags)) { 1093 pr_err("Can't attach %s: shutting down", 1094 dc->backing_dev_name); 1095 return -EINVAL; 1096 } 1097 1098 if (dc->sb.block_size < c->sb.block_size) { 1099 /* Will die */ 1100 pr_err("Couldn't attach %s: block size less than set's block size", 1101 dc->backing_dev_name); 1102 return -EINVAL; 1103 } 1104 1105 /* Check whether already attached */ 1106 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { 1107 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { 1108 pr_err("Tried to attach %s but duplicate UUID already attached", 1109 dc->backing_dev_name); 1110 1111 return -EINVAL; 1112 } 1113 } 1114 1115 u = uuid_find(c, dc->sb.uuid); 1116 1117 if (u && 1118 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || 1119 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { 1120 memcpy(u->uuid, invalid_uuid, 16); 1121 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds()); 1122 u = NULL; 1123 } 1124 1125 if (!u) { 1126 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1127 pr_err("Couldn't find uuid for %s in set", 1128 dc->backing_dev_name); 1129 return -ENOENT; 1130 } 1131 1132 u = uuid_find_empty(c); 1133 if (!u) { 1134 pr_err("Not caching %s, no room for UUID", 1135 dc->backing_dev_name); 1136 return -EINVAL; 1137 } 1138 } 1139 1140 /* 1141 * Deadlocks since we're called via sysfs... 1142 * sysfs_remove_file(&dc->kobj, &sysfs_attach); 1143 */ 1144 1145 if (bch_is_zero(u->uuid, 16)) { 1146 struct closure cl; 1147 1148 closure_init_stack(&cl); 1149 1150 memcpy(u->uuid, dc->sb.uuid, 16); 1151 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); 1152 u->first_reg = u->last_reg = rtime; 1153 bch_uuid_write(c); 1154 1155 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); 1156 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); 1157 1158 bch_write_bdev_super(dc, &cl); 1159 closure_sync(&cl); 1160 } else { 1161 u->last_reg = rtime; 1162 bch_uuid_write(c); 1163 } 1164 1165 bcache_device_attach(&dc->disk, c, u - c->uuids); 1166 list_move(&dc->list, &c->cached_devs); 1167 calc_cached_dev_sectors(c); 1168 1169 /* 1170 * dc->c must be set before dc->count != 0 - paired with the mb in 1171 * cached_dev_get() 1172 */ 1173 smp_wmb(); 1174 refcount_set(&dc->count, 1); 1175 1176 /* Block writeback thread, but spawn it */ 1177 down_write(&dc->writeback_lock); 1178 if (bch_cached_dev_writeback_start(dc)) { 1179 up_write(&dc->writeback_lock); 1180 pr_err("Couldn't start writeback facilities for %s", 1181 dc->disk.disk->disk_name); 1182 return -ENOMEM; 1183 } 1184 1185 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { 1186 atomic_set(&dc->has_dirty, 1); 1187 bch_writeback_queue(dc); 1188 } 1189 1190 bch_sectors_dirty_init(&dc->disk); 1191 1192 ret = bch_cached_dev_run(dc); 1193 if (ret && (ret != -EBUSY)) { 1194 up_write(&dc->writeback_lock); 1195 /* 1196 * bch_register_lock is held, bcache_device_stop() is not 1197 * able to be directly called. The kthread and kworker 1198 * created previously in bch_cached_dev_writeback_start() 1199 * have to be stopped manually here. 1200 */ 1201 kthread_stop(dc->writeback_thread); 1202 cancel_writeback_rate_update_dwork(dc); 1203 pr_err("Couldn't run cached device %s", 1204 dc->backing_dev_name); 1205 return ret; 1206 } 1207 1208 bcache_device_link(&dc->disk, c, "bdev"); 1209 atomic_inc(&c->attached_dev_nr); 1210 1211 /* Allow the writeback thread to proceed */ 1212 up_write(&dc->writeback_lock); 1213 1214 pr_info("Caching %s as %s on set %pU", 1215 dc->backing_dev_name, 1216 dc->disk.disk->disk_name, 1217 dc->disk.c->sb.set_uuid); 1218 return 0; 1219 } 1220 1221 /* when dc->disk.kobj released */ 1222 void bch_cached_dev_release(struct kobject *kobj) 1223 { 1224 struct cached_dev *dc = container_of(kobj, struct cached_dev, 1225 disk.kobj); 1226 kfree(dc); 1227 module_put(THIS_MODULE); 1228 } 1229 1230 static void cached_dev_free(struct closure *cl) 1231 { 1232 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1233 1234 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) 1235 cancel_writeback_rate_update_dwork(dc); 1236 1237 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 1238 kthread_stop(dc->writeback_thread); 1239 if (!IS_ERR_OR_NULL(dc->status_update_thread)) 1240 kthread_stop(dc->status_update_thread); 1241 1242 mutex_lock(&bch_register_lock); 1243 1244 if (atomic_read(&dc->running)) 1245 bd_unlink_disk_holder(dc->bdev, dc->disk.disk); 1246 bcache_device_free(&dc->disk); 1247 list_del(&dc->list); 1248 1249 mutex_unlock(&bch_register_lock); 1250 1251 if (!IS_ERR_OR_NULL(dc->bdev)) 1252 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 1253 1254 wake_up(&unregister_wait); 1255 1256 kobject_put(&dc->disk.kobj); 1257 } 1258 1259 static void cached_dev_flush(struct closure *cl) 1260 { 1261 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); 1262 struct bcache_device *d = &dc->disk; 1263 1264 mutex_lock(&bch_register_lock); 1265 bcache_device_unlink(d); 1266 mutex_unlock(&bch_register_lock); 1267 1268 bch_cache_accounting_destroy(&dc->accounting); 1269 kobject_del(&d->kobj); 1270 1271 continue_at(cl, cached_dev_free, system_wq); 1272 } 1273 1274 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size) 1275 { 1276 int ret; 1277 struct io *io; 1278 struct request_queue *q = bdev_get_queue(dc->bdev); 1279 1280 __module_get(THIS_MODULE); 1281 INIT_LIST_HEAD(&dc->list); 1282 closure_init(&dc->disk.cl, NULL); 1283 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); 1284 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); 1285 INIT_WORK(&dc->detach, cached_dev_detach_finish); 1286 sema_init(&dc->sb_write_mutex, 1); 1287 INIT_LIST_HEAD(&dc->io_lru); 1288 spin_lock_init(&dc->io_lock); 1289 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); 1290 1291 dc->sequential_cutoff = 4 << 20; 1292 1293 for (io = dc->io; io < dc->io + RECENT_IO; io++) { 1294 list_add(&io->lru, &dc->io_lru); 1295 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); 1296 } 1297 1298 dc->disk.stripe_size = q->limits.io_opt >> 9; 1299 1300 if (dc->disk.stripe_size) 1301 dc->partial_stripes_expensive = 1302 q->limits.raid_partial_stripes_expensive; 1303 1304 ret = bcache_device_init(&dc->disk, block_size, 1305 dc->bdev->bd_part->nr_sects - dc->sb.data_offset); 1306 if (ret) 1307 return ret; 1308 1309 dc->disk.disk->queue->backing_dev_info->ra_pages = 1310 max(dc->disk.disk->queue->backing_dev_info->ra_pages, 1311 q->backing_dev_info->ra_pages); 1312 1313 atomic_set(&dc->io_errors, 0); 1314 dc->io_disable = false; 1315 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; 1316 /* default to auto */ 1317 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; 1318 1319 bch_cached_dev_request_init(dc); 1320 bch_cached_dev_writeback_init(dc); 1321 return 0; 1322 } 1323 1324 /* Cached device - bcache superblock */ 1325 1326 static int register_bdev(struct cache_sb *sb, struct page *sb_page, 1327 struct block_device *bdev, 1328 struct cached_dev *dc) 1329 { 1330 const char *err = "cannot allocate memory"; 1331 struct cache_set *c; 1332 int ret = -ENOMEM; 1333 1334 bdevname(bdev, dc->backing_dev_name); 1335 memcpy(&dc->sb, sb, sizeof(struct cache_sb)); 1336 dc->bdev = bdev; 1337 dc->bdev->bd_holder = dc; 1338 1339 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1); 1340 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page; 1341 get_page(sb_page); 1342 1343 1344 if (cached_dev_init(dc, sb->block_size << 9)) 1345 goto err; 1346 1347 err = "error creating kobject"; 1348 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, 1349 "bcache")) 1350 goto err; 1351 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) 1352 goto err; 1353 1354 pr_info("registered backing device %s", dc->backing_dev_name); 1355 1356 list_add(&dc->list, &uncached_devices); 1357 /* attach to a matched cache set if it exists */ 1358 list_for_each_entry(c, &bch_cache_sets, list) 1359 bch_cached_dev_attach(dc, c, NULL); 1360 1361 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || 1362 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) { 1363 err = "failed to run cached device"; 1364 ret = bch_cached_dev_run(dc); 1365 if (ret) 1366 goto err; 1367 } 1368 1369 return 0; 1370 err: 1371 pr_notice("error %s: %s", dc->backing_dev_name, err); 1372 bcache_device_stop(&dc->disk); 1373 return ret; 1374 } 1375 1376 /* Flash only volumes */ 1377 1378 /* When d->kobj released */ 1379 void bch_flash_dev_release(struct kobject *kobj) 1380 { 1381 struct bcache_device *d = container_of(kobj, struct bcache_device, 1382 kobj); 1383 kfree(d); 1384 } 1385 1386 static void flash_dev_free(struct closure *cl) 1387 { 1388 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1389 1390 mutex_lock(&bch_register_lock); 1391 atomic_long_sub(bcache_dev_sectors_dirty(d), 1392 &d->c->flash_dev_dirty_sectors); 1393 bcache_device_free(d); 1394 mutex_unlock(&bch_register_lock); 1395 kobject_put(&d->kobj); 1396 } 1397 1398 static void flash_dev_flush(struct closure *cl) 1399 { 1400 struct bcache_device *d = container_of(cl, struct bcache_device, cl); 1401 1402 mutex_lock(&bch_register_lock); 1403 bcache_device_unlink(d); 1404 mutex_unlock(&bch_register_lock); 1405 kobject_del(&d->kobj); 1406 continue_at(cl, flash_dev_free, system_wq); 1407 } 1408 1409 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) 1410 { 1411 struct bcache_device *d = kzalloc(sizeof(struct bcache_device), 1412 GFP_KERNEL); 1413 if (!d) 1414 return -ENOMEM; 1415 1416 closure_init(&d->cl, NULL); 1417 set_closure_fn(&d->cl, flash_dev_flush, system_wq); 1418 1419 kobject_init(&d->kobj, &bch_flash_dev_ktype); 1420 1421 if (bcache_device_init(d, block_bytes(c), u->sectors)) 1422 goto err; 1423 1424 bcache_device_attach(d, c, u - c->uuids); 1425 bch_sectors_dirty_init(d); 1426 bch_flash_dev_request_init(d); 1427 add_disk(d->disk); 1428 1429 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) 1430 goto err; 1431 1432 bcache_device_link(d, c, "volume"); 1433 1434 return 0; 1435 err: 1436 kobject_put(&d->kobj); 1437 return -ENOMEM; 1438 } 1439 1440 static int flash_devs_run(struct cache_set *c) 1441 { 1442 int ret = 0; 1443 struct uuid_entry *u; 1444 1445 for (u = c->uuids; 1446 u < c->uuids + c->nr_uuids && !ret; 1447 u++) 1448 if (UUID_FLASH_ONLY(u)) 1449 ret = flash_dev_run(c, u); 1450 1451 return ret; 1452 } 1453 1454 int bch_flash_dev_create(struct cache_set *c, uint64_t size) 1455 { 1456 struct uuid_entry *u; 1457 1458 if (test_bit(CACHE_SET_STOPPING, &c->flags)) 1459 return -EINTR; 1460 1461 if (!test_bit(CACHE_SET_RUNNING, &c->flags)) 1462 return -EPERM; 1463 1464 u = uuid_find_empty(c); 1465 if (!u) { 1466 pr_err("Can't create volume, no room for UUID"); 1467 return -EINVAL; 1468 } 1469 1470 get_random_bytes(u->uuid, 16); 1471 memset(u->label, 0, 32); 1472 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); 1473 1474 SET_UUID_FLASH_ONLY(u, 1); 1475 u->sectors = size >> 9; 1476 1477 bch_uuid_write(c); 1478 1479 return flash_dev_run(c, u); 1480 } 1481 1482 bool bch_cached_dev_error(struct cached_dev *dc) 1483 { 1484 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) 1485 return false; 1486 1487 dc->io_disable = true; 1488 /* make others know io_disable is true earlier */ 1489 smp_mb(); 1490 1491 pr_err("stop %s: too many IO errors on backing device %s\n", 1492 dc->disk.disk->disk_name, dc->backing_dev_name); 1493 1494 bcache_device_stop(&dc->disk); 1495 return true; 1496 } 1497 1498 /* Cache set */ 1499 1500 __printf(2, 3) 1501 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) 1502 { 1503 va_list args; 1504 1505 if (c->on_error != ON_ERROR_PANIC && 1506 test_bit(CACHE_SET_STOPPING, &c->flags)) 1507 return false; 1508 1509 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1510 pr_info("CACHE_SET_IO_DISABLE already set"); 1511 1512 /* 1513 * XXX: we can be called from atomic context 1514 * acquire_console_sem(); 1515 */ 1516 1517 pr_err("bcache: error on %pU: ", c->sb.set_uuid); 1518 1519 va_start(args, fmt); 1520 vprintk(fmt, args); 1521 va_end(args); 1522 1523 pr_err(", disabling caching\n"); 1524 1525 if (c->on_error == ON_ERROR_PANIC) 1526 panic("panic forced after error\n"); 1527 1528 bch_cache_set_unregister(c); 1529 return true; 1530 } 1531 1532 /* When c->kobj released */ 1533 void bch_cache_set_release(struct kobject *kobj) 1534 { 1535 struct cache_set *c = container_of(kobj, struct cache_set, kobj); 1536 1537 kfree(c); 1538 module_put(THIS_MODULE); 1539 } 1540 1541 static void cache_set_free(struct closure *cl) 1542 { 1543 struct cache_set *c = container_of(cl, struct cache_set, cl); 1544 struct cache *ca; 1545 unsigned int i; 1546 1547 debugfs_remove(c->debug); 1548 1549 bch_open_buckets_free(c); 1550 bch_btree_cache_free(c); 1551 bch_journal_free(c); 1552 1553 mutex_lock(&bch_register_lock); 1554 for_each_cache(ca, c, i) 1555 if (ca) { 1556 ca->set = NULL; 1557 c->cache[ca->sb.nr_this_dev] = NULL; 1558 kobject_put(&ca->kobj); 1559 } 1560 1561 bch_bset_sort_state_free(&c->sort); 1562 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 1563 1564 if (c->moving_gc_wq) 1565 destroy_workqueue(c->moving_gc_wq); 1566 bioset_exit(&c->bio_split); 1567 mempool_exit(&c->fill_iter); 1568 mempool_exit(&c->bio_meta); 1569 mempool_exit(&c->search); 1570 kfree(c->devices); 1571 1572 list_del(&c->list); 1573 mutex_unlock(&bch_register_lock); 1574 1575 pr_info("Cache set %pU unregistered", c->sb.set_uuid); 1576 wake_up(&unregister_wait); 1577 1578 closure_debug_destroy(&c->cl); 1579 kobject_put(&c->kobj); 1580 } 1581 1582 static void cache_set_flush(struct closure *cl) 1583 { 1584 struct cache_set *c = container_of(cl, struct cache_set, caching); 1585 struct cache *ca; 1586 struct btree *b; 1587 unsigned int i; 1588 1589 bch_cache_accounting_destroy(&c->accounting); 1590 1591 kobject_put(&c->internal); 1592 kobject_del(&c->kobj); 1593 1594 if (!IS_ERR_OR_NULL(c->gc_thread)) 1595 kthread_stop(c->gc_thread); 1596 1597 if (!IS_ERR_OR_NULL(c->root)) 1598 list_add(&c->root->list, &c->btree_cache); 1599 1600 /* 1601 * Avoid flushing cached nodes if cache set is retiring 1602 * due to too many I/O errors detected. 1603 */ 1604 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1605 list_for_each_entry(b, &c->btree_cache, list) { 1606 mutex_lock(&b->write_lock); 1607 if (btree_node_dirty(b)) 1608 __bch_btree_node_write(b, NULL); 1609 mutex_unlock(&b->write_lock); 1610 } 1611 1612 for_each_cache(ca, c, i) 1613 if (ca->alloc_thread) 1614 kthread_stop(ca->alloc_thread); 1615 1616 if (c->journal.cur) { 1617 cancel_delayed_work_sync(&c->journal.work); 1618 /* flush last journal entry if needed */ 1619 c->journal.work.work.func(&c->journal.work.work); 1620 } 1621 1622 closure_return(cl); 1623 } 1624 1625 /* 1626 * This function is only called when CACHE_SET_IO_DISABLE is set, which means 1627 * cache set is unregistering due to too many I/O errors. In this condition, 1628 * the bcache device might be stopped, it depends on stop_when_cache_set_failed 1629 * value and whether the broken cache has dirty data: 1630 * 1631 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device 1632 * BCH_CACHED_STOP_AUTO 0 NO 1633 * BCH_CACHED_STOP_AUTO 1 YES 1634 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES 1635 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES 1636 * 1637 * The expected behavior is, if stop_when_cache_set_failed is configured to 1638 * "auto" via sysfs interface, the bcache device will not be stopped if the 1639 * backing device is clean on the broken cache device. 1640 */ 1641 static void conditional_stop_bcache_device(struct cache_set *c, 1642 struct bcache_device *d, 1643 struct cached_dev *dc) 1644 { 1645 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { 1646 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.", 1647 d->disk->disk_name, c->sb.set_uuid); 1648 bcache_device_stop(d); 1649 } else if (atomic_read(&dc->has_dirty)) { 1650 /* 1651 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1652 * and dc->has_dirty == 1 1653 */ 1654 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.", 1655 d->disk->disk_name); 1656 /* 1657 * There might be a small time gap that cache set is 1658 * released but bcache device is not. Inside this time 1659 * gap, regular I/O requests will directly go into 1660 * backing device as no cache set attached to. This 1661 * behavior may also introduce potential inconsistence 1662 * data in writeback mode while cache is dirty. 1663 * Therefore before calling bcache_device_stop() due 1664 * to a broken cache device, dc->io_disable should be 1665 * explicitly set to true. 1666 */ 1667 dc->io_disable = true; 1668 /* make others know io_disable is true earlier */ 1669 smp_mb(); 1670 bcache_device_stop(d); 1671 } else { 1672 /* 1673 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO 1674 * and dc->has_dirty == 0 1675 */ 1676 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.", 1677 d->disk->disk_name); 1678 } 1679 } 1680 1681 static void __cache_set_unregister(struct closure *cl) 1682 { 1683 struct cache_set *c = container_of(cl, struct cache_set, caching); 1684 struct cached_dev *dc; 1685 struct bcache_device *d; 1686 size_t i; 1687 1688 mutex_lock(&bch_register_lock); 1689 1690 for (i = 0; i < c->devices_max_used; i++) { 1691 d = c->devices[i]; 1692 if (!d) 1693 continue; 1694 1695 if (!UUID_FLASH_ONLY(&c->uuids[i]) && 1696 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { 1697 dc = container_of(d, struct cached_dev, disk); 1698 bch_cached_dev_detach(dc); 1699 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) 1700 conditional_stop_bcache_device(c, d, dc); 1701 } else { 1702 bcache_device_stop(d); 1703 } 1704 } 1705 1706 mutex_unlock(&bch_register_lock); 1707 1708 continue_at(cl, cache_set_flush, system_wq); 1709 } 1710 1711 void bch_cache_set_stop(struct cache_set *c) 1712 { 1713 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) 1714 /* closure_fn set to __cache_set_unregister() */ 1715 closure_queue(&c->caching); 1716 } 1717 1718 void bch_cache_set_unregister(struct cache_set *c) 1719 { 1720 set_bit(CACHE_SET_UNREGISTERING, &c->flags); 1721 bch_cache_set_stop(c); 1722 } 1723 1724 #define alloc_bucket_pages(gfp, c) \ 1725 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) 1726 1727 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 1728 { 1729 int iter_size; 1730 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); 1731 1732 if (!c) 1733 return NULL; 1734 1735 __module_get(THIS_MODULE); 1736 closure_init(&c->cl, NULL); 1737 set_closure_fn(&c->cl, cache_set_free, system_wq); 1738 1739 closure_init(&c->caching, &c->cl); 1740 set_closure_fn(&c->caching, __cache_set_unregister, system_wq); 1741 1742 /* Maybe create continue_at_noreturn() and use it here? */ 1743 closure_set_stopped(&c->cl); 1744 closure_put(&c->cl); 1745 1746 kobject_init(&c->kobj, &bch_cache_set_ktype); 1747 kobject_init(&c->internal, &bch_cache_set_internal_ktype); 1748 1749 bch_cache_accounting_init(&c->accounting, &c->cl); 1750 1751 memcpy(c->sb.set_uuid, sb->set_uuid, 16); 1752 c->sb.block_size = sb->block_size; 1753 c->sb.bucket_size = sb->bucket_size; 1754 c->sb.nr_in_set = sb->nr_in_set; 1755 c->sb.last_mount = sb->last_mount; 1756 c->bucket_bits = ilog2(sb->bucket_size); 1757 c->block_bits = ilog2(sb->block_size); 1758 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); 1759 c->devices_max_used = 0; 1760 atomic_set(&c->attached_dev_nr, 0); 1761 c->btree_pages = bucket_pages(c); 1762 if (c->btree_pages > BTREE_MAX_PAGES) 1763 c->btree_pages = max_t(int, c->btree_pages / 4, 1764 BTREE_MAX_PAGES); 1765 1766 sema_init(&c->sb_write_mutex, 1); 1767 mutex_init(&c->bucket_lock); 1768 init_waitqueue_head(&c->btree_cache_wait); 1769 init_waitqueue_head(&c->bucket_wait); 1770 init_waitqueue_head(&c->gc_wait); 1771 sema_init(&c->uuid_write_mutex, 1); 1772 1773 spin_lock_init(&c->btree_gc_time.lock); 1774 spin_lock_init(&c->btree_split_time.lock); 1775 spin_lock_init(&c->btree_read_time.lock); 1776 1777 bch_moving_init_cache_set(c); 1778 1779 INIT_LIST_HEAD(&c->list); 1780 INIT_LIST_HEAD(&c->cached_devs); 1781 INIT_LIST_HEAD(&c->btree_cache); 1782 INIT_LIST_HEAD(&c->btree_cache_freeable); 1783 INIT_LIST_HEAD(&c->btree_cache_freed); 1784 INIT_LIST_HEAD(&c->data_buckets); 1785 1786 iter_size = (sb->bucket_size / sb->block_size + 1) * 1787 sizeof(struct btree_iter_set); 1788 1789 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || 1790 mempool_init_slab_pool(&c->search, 32, bch_search_cache) || 1791 mempool_init_kmalloc_pool(&c->bio_meta, 2, 1792 sizeof(struct bbio) + sizeof(struct bio_vec) * 1793 bucket_pages(c)) || 1794 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || 1795 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), 1796 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || 1797 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || 1798 !(c->moving_gc_wq = alloc_workqueue("bcache_gc", 1799 WQ_MEM_RECLAIM, 0)) || 1800 bch_journal_alloc(c) || 1801 bch_btree_cache_alloc(c) || 1802 bch_open_buckets_alloc(c) || 1803 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) 1804 goto err; 1805 1806 c->congested_read_threshold_us = 2000; 1807 c->congested_write_threshold_us = 20000; 1808 c->error_limit = DEFAULT_IO_ERROR_LIMIT; 1809 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 1810 1811 return c; 1812 err: 1813 bch_cache_set_unregister(c); 1814 return NULL; 1815 } 1816 1817 static int run_cache_set(struct cache_set *c) 1818 { 1819 const char *err = "cannot allocate memory"; 1820 struct cached_dev *dc, *t; 1821 struct cache *ca; 1822 struct closure cl; 1823 unsigned int i; 1824 LIST_HEAD(journal); 1825 struct journal_replay *l; 1826 1827 closure_init_stack(&cl); 1828 1829 for_each_cache(ca, c, i) 1830 c->nbuckets += ca->sb.nbuckets; 1831 set_gc_sectors(c); 1832 1833 if (CACHE_SYNC(&c->sb)) { 1834 struct bkey *k; 1835 struct jset *j; 1836 1837 err = "cannot allocate memory for journal"; 1838 if (bch_journal_read(c, &journal)) 1839 goto err; 1840 1841 pr_debug("btree_journal_read() done"); 1842 1843 err = "no journal entries found"; 1844 if (list_empty(&journal)) 1845 goto err; 1846 1847 j = &list_entry(journal.prev, struct journal_replay, list)->j; 1848 1849 err = "IO error reading priorities"; 1850 for_each_cache(ca, c, i) 1851 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); 1852 1853 /* 1854 * If prio_read() fails it'll call cache_set_error and we'll 1855 * tear everything down right away, but if we perhaps checked 1856 * sooner we could avoid journal replay. 1857 */ 1858 1859 k = &j->btree_root; 1860 1861 err = "bad btree root"; 1862 if (__bch_btree_ptr_invalid(c, k)) 1863 goto err; 1864 1865 err = "error reading btree root"; 1866 c->root = bch_btree_node_get(c, NULL, k, 1867 j->btree_level, 1868 true, NULL); 1869 if (IS_ERR_OR_NULL(c->root)) 1870 goto err; 1871 1872 list_del_init(&c->root->list); 1873 rw_unlock(true, c->root); 1874 1875 err = uuid_read(c, j, &cl); 1876 if (err) 1877 goto err; 1878 1879 err = "error in recovery"; 1880 if (bch_btree_check(c)) 1881 goto err; 1882 1883 /* 1884 * bch_btree_check() may occupy too much system memory which 1885 * has negative effects to user space application (e.g. data 1886 * base) performance. Shrink the mca cache memory proactively 1887 * here to avoid competing memory with user space workloads.. 1888 */ 1889 if (!c->shrinker_disabled) { 1890 struct shrink_control sc; 1891 1892 sc.gfp_mask = GFP_KERNEL; 1893 sc.nr_to_scan = c->btree_cache_used * c->btree_pages; 1894 /* first run to clear b->accessed tag */ 1895 c->shrink.scan_objects(&c->shrink, &sc); 1896 /* second run to reap non-accessed nodes */ 1897 c->shrink.scan_objects(&c->shrink, &sc); 1898 } 1899 1900 bch_journal_mark(c, &journal); 1901 bch_initial_gc_finish(c); 1902 pr_debug("btree_check() done"); 1903 1904 /* 1905 * bcache_journal_next() can't happen sooner, or 1906 * btree_gc_finish() will give spurious errors about last_gc > 1907 * gc_gen - this is a hack but oh well. 1908 */ 1909 bch_journal_next(&c->journal); 1910 1911 err = "error starting allocator thread"; 1912 for_each_cache(ca, c, i) 1913 if (bch_cache_allocator_start(ca)) 1914 goto err; 1915 1916 /* 1917 * First place it's safe to allocate: btree_check() and 1918 * btree_gc_finish() have to run before we have buckets to 1919 * allocate, and bch_bucket_alloc_set() might cause a journal 1920 * entry to be written so bcache_journal_next() has to be called 1921 * first. 1922 * 1923 * If the uuids were in the old format we have to rewrite them 1924 * before the next journal entry is written: 1925 */ 1926 if (j->version < BCACHE_JSET_VERSION_UUID) 1927 __uuid_write(c); 1928 1929 err = "bcache: replay journal failed"; 1930 if (bch_journal_replay(c, &journal)) 1931 goto err; 1932 } else { 1933 pr_notice("invalidating existing data"); 1934 1935 for_each_cache(ca, c, i) { 1936 unsigned int j; 1937 1938 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 1939 2, SB_JOURNAL_BUCKETS); 1940 1941 for (j = 0; j < ca->sb.keys; j++) 1942 ca->sb.d[j] = ca->sb.first_bucket + j; 1943 } 1944 1945 bch_initial_gc_finish(c); 1946 1947 err = "error starting allocator thread"; 1948 for_each_cache(ca, c, i) 1949 if (bch_cache_allocator_start(ca)) 1950 goto err; 1951 1952 mutex_lock(&c->bucket_lock); 1953 for_each_cache(ca, c, i) 1954 bch_prio_write(ca); 1955 mutex_unlock(&c->bucket_lock); 1956 1957 err = "cannot allocate new UUID bucket"; 1958 if (__uuid_write(c)) 1959 goto err; 1960 1961 err = "cannot allocate new btree root"; 1962 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); 1963 if (IS_ERR_OR_NULL(c->root)) 1964 goto err; 1965 1966 mutex_lock(&c->root->write_lock); 1967 bkey_copy_key(&c->root->key, &MAX_KEY); 1968 bch_btree_node_write(c->root, &cl); 1969 mutex_unlock(&c->root->write_lock); 1970 1971 bch_btree_set_root(c->root); 1972 rw_unlock(true, c->root); 1973 1974 /* 1975 * We don't want to write the first journal entry until 1976 * everything is set up - fortunately journal entries won't be 1977 * written until the SET_CACHE_SYNC() here: 1978 */ 1979 SET_CACHE_SYNC(&c->sb, true); 1980 1981 bch_journal_next(&c->journal); 1982 bch_journal_meta(c, &cl); 1983 } 1984 1985 err = "error starting gc thread"; 1986 if (bch_gc_thread_start(c)) 1987 goto err; 1988 1989 closure_sync(&cl); 1990 c->sb.last_mount = (u32)ktime_get_real_seconds(); 1991 bcache_write_super(c); 1992 1993 list_for_each_entry_safe(dc, t, &uncached_devices, list) 1994 bch_cached_dev_attach(dc, c, NULL); 1995 1996 flash_devs_run(c); 1997 1998 set_bit(CACHE_SET_RUNNING, &c->flags); 1999 return 0; 2000 err: 2001 while (!list_empty(&journal)) { 2002 l = list_first_entry(&journal, struct journal_replay, list); 2003 list_del(&l->list); 2004 kfree(l); 2005 } 2006 2007 closure_sync(&cl); 2008 2009 bch_cache_set_error(c, "%s", err); 2010 2011 return -EIO; 2012 } 2013 2014 static bool can_attach_cache(struct cache *ca, struct cache_set *c) 2015 { 2016 return ca->sb.block_size == c->sb.block_size && 2017 ca->sb.bucket_size == c->sb.bucket_size && 2018 ca->sb.nr_in_set == c->sb.nr_in_set; 2019 } 2020 2021 static const char *register_cache_set(struct cache *ca) 2022 { 2023 char buf[12]; 2024 const char *err = "cannot allocate memory"; 2025 struct cache_set *c; 2026 2027 list_for_each_entry(c, &bch_cache_sets, list) 2028 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { 2029 if (c->cache[ca->sb.nr_this_dev]) 2030 return "duplicate cache set member"; 2031 2032 if (!can_attach_cache(ca, c)) 2033 return "cache sb does not match set"; 2034 2035 if (!CACHE_SYNC(&ca->sb)) 2036 SET_CACHE_SYNC(&c->sb, false); 2037 2038 goto found; 2039 } 2040 2041 c = bch_cache_set_alloc(&ca->sb); 2042 if (!c) 2043 return err; 2044 2045 err = "error creating kobject"; 2046 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || 2047 kobject_add(&c->internal, &c->kobj, "internal")) 2048 goto err; 2049 2050 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) 2051 goto err; 2052 2053 bch_debug_init_cache_set(c); 2054 2055 list_add(&c->list, &bch_cache_sets); 2056 found: 2057 sprintf(buf, "cache%i", ca->sb.nr_this_dev); 2058 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || 2059 sysfs_create_link(&c->kobj, &ca->kobj, buf)) 2060 goto err; 2061 2062 if (ca->sb.seq > c->sb.seq) { 2063 c->sb.version = ca->sb.version; 2064 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 2065 c->sb.flags = ca->sb.flags; 2066 c->sb.seq = ca->sb.seq; 2067 pr_debug("set version = %llu", c->sb.version); 2068 } 2069 2070 kobject_get(&ca->kobj); 2071 ca->set = c; 2072 ca->set->cache[ca->sb.nr_this_dev] = ca; 2073 c->cache_by_alloc[c->caches_loaded++] = ca; 2074 2075 if (c->caches_loaded == c->sb.nr_in_set) { 2076 err = "failed to run cache set"; 2077 if (run_cache_set(c) < 0) 2078 goto err; 2079 } 2080 2081 return NULL; 2082 err: 2083 bch_cache_set_unregister(c); 2084 return err; 2085 } 2086 2087 /* Cache device */ 2088 2089 /* When ca->kobj released */ 2090 void bch_cache_release(struct kobject *kobj) 2091 { 2092 struct cache *ca = container_of(kobj, struct cache, kobj); 2093 unsigned int i; 2094 2095 if (ca->set) { 2096 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); 2097 ca->set->cache[ca->sb.nr_this_dev] = NULL; 2098 } 2099 2100 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); 2101 kfree(ca->prio_buckets); 2102 vfree(ca->buckets); 2103 2104 free_heap(&ca->heap); 2105 free_fifo(&ca->free_inc); 2106 2107 for (i = 0; i < RESERVE_NR; i++) 2108 free_fifo(&ca->free[i]); 2109 2110 if (ca->sb_bio.bi_inline_vecs[0].bv_page) 2111 put_page(bio_first_page_all(&ca->sb_bio)); 2112 2113 if (!IS_ERR_OR_NULL(ca->bdev)) 2114 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2115 2116 kfree(ca); 2117 module_put(THIS_MODULE); 2118 } 2119 2120 static int cache_alloc(struct cache *ca) 2121 { 2122 size_t free; 2123 size_t btree_buckets; 2124 struct bucket *b; 2125 int ret = -ENOMEM; 2126 const char *err = NULL; 2127 2128 __module_get(THIS_MODULE); 2129 kobject_init(&ca->kobj, &bch_cache_ktype); 2130 2131 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8); 2132 2133 /* 2134 * when ca->sb.njournal_buckets is not zero, journal exists, 2135 * and in bch_journal_replay(), tree node may split, 2136 * so bucket of RESERVE_BTREE type is needed, 2137 * the worst situation is all journal buckets are valid journal, 2138 * and all the keys need to replay, 2139 * so the number of RESERVE_BTREE type buckets should be as much 2140 * as journal buckets 2141 */ 2142 btree_buckets = ca->sb.njournal_buckets ?: 8; 2143 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; 2144 if (!free) { 2145 ret = -EPERM; 2146 err = "ca->sb.nbuckets is too small"; 2147 goto err_free; 2148 } 2149 2150 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, 2151 GFP_KERNEL)) { 2152 err = "ca->free[RESERVE_BTREE] alloc failed"; 2153 goto err_btree_alloc; 2154 } 2155 2156 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), 2157 GFP_KERNEL)) { 2158 err = "ca->free[RESERVE_PRIO] alloc failed"; 2159 goto err_prio_alloc; 2160 } 2161 2162 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) { 2163 err = "ca->free[RESERVE_MOVINGGC] alloc failed"; 2164 goto err_movinggc_alloc; 2165 } 2166 2167 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) { 2168 err = "ca->free[RESERVE_NONE] alloc failed"; 2169 goto err_none_alloc; 2170 } 2171 2172 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) { 2173 err = "ca->free_inc alloc failed"; 2174 goto err_free_inc_alloc; 2175 } 2176 2177 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) { 2178 err = "ca->heap alloc failed"; 2179 goto err_heap_alloc; 2180 } 2181 2182 ca->buckets = vzalloc(array_size(sizeof(struct bucket), 2183 ca->sb.nbuckets)); 2184 if (!ca->buckets) { 2185 err = "ca->buckets alloc failed"; 2186 goto err_buckets_alloc; 2187 } 2188 2189 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), 2190 prio_buckets(ca), 2), 2191 GFP_KERNEL); 2192 if (!ca->prio_buckets) { 2193 err = "ca->prio_buckets alloc failed"; 2194 goto err_prio_buckets_alloc; 2195 } 2196 2197 ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca); 2198 if (!ca->disk_buckets) { 2199 err = "ca->disk_buckets alloc failed"; 2200 goto err_disk_buckets_alloc; 2201 } 2202 2203 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); 2204 2205 for_each_bucket(b, ca) 2206 atomic_set(&b->pin, 0); 2207 return 0; 2208 2209 err_disk_buckets_alloc: 2210 kfree(ca->prio_buckets); 2211 err_prio_buckets_alloc: 2212 vfree(ca->buckets); 2213 err_buckets_alloc: 2214 free_heap(&ca->heap); 2215 err_heap_alloc: 2216 free_fifo(&ca->free_inc); 2217 err_free_inc_alloc: 2218 free_fifo(&ca->free[RESERVE_NONE]); 2219 err_none_alloc: 2220 free_fifo(&ca->free[RESERVE_MOVINGGC]); 2221 err_movinggc_alloc: 2222 free_fifo(&ca->free[RESERVE_PRIO]); 2223 err_prio_alloc: 2224 free_fifo(&ca->free[RESERVE_BTREE]); 2225 err_btree_alloc: 2226 err_free: 2227 module_put(THIS_MODULE); 2228 if (err) 2229 pr_notice("error %s: %s", ca->cache_dev_name, err); 2230 return ret; 2231 } 2232 2233 static int register_cache(struct cache_sb *sb, struct page *sb_page, 2234 struct block_device *bdev, struct cache *ca) 2235 { 2236 const char *err = NULL; /* must be set for any error case */ 2237 int ret = 0; 2238 2239 bdevname(bdev, ca->cache_dev_name); 2240 memcpy(&ca->sb, sb, sizeof(struct cache_sb)); 2241 ca->bdev = bdev; 2242 ca->bdev->bd_holder = ca; 2243 2244 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1); 2245 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; 2246 get_page(sb_page); 2247 2248 if (blk_queue_discard(bdev_get_queue(bdev))) 2249 ca->discard = CACHE_DISCARD(&ca->sb); 2250 2251 ret = cache_alloc(ca); 2252 if (ret != 0) { 2253 /* 2254 * If we failed here, it means ca->kobj is not initialized yet, 2255 * kobject_put() won't be called and there is no chance to 2256 * call blkdev_put() to bdev in bch_cache_release(). So we 2257 * explicitly call blkdev_put() here. 2258 */ 2259 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2260 if (ret == -ENOMEM) 2261 err = "cache_alloc(): -ENOMEM"; 2262 else if (ret == -EPERM) 2263 err = "cache_alloc(): cache device is too small"; 2264 else 2265 err = "cache_alloc(): unknown error"; 2266 goto err; 2267 } 2268 2269 if (kobject_add(&ca->kobj, 2270 &part_to_dev(bdev->bd_part)->kobj, 2271 "bcache")) { 2272 err = "error calling kobject_add"; 2273 ret = -ENOMEM; 2274 goto out; 2275 } 2276 2277 mutex_lock(&bch_register_lock); 2278 err = register_cache_set(ca); 2279 mutex_unlock(&bch_register_lock); 2280 2281 if (err) { 2282 ret = -ENODEV; 2283 goto out; 2284 } 2285 2286 pr_info("registered cache device %s", ca->cache_dev_name); 2287 2288 out: 2289 kobject_put(&ca->kobj); 2290 2291 err: 2292 if (err) 2293 pr_notice("error %s: %s", ca->cache_dev_name, err); 2294 2295 return ret; 2296 } 2297 2298 /* Global interfaces/init */ 2299 2300 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2301 const char *buffer, size_t size); 2302 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k, 2303 struct kobj_attribute *attr, 2304 const char *buffer, size_t size); 2305 2306 kobj_attribute_write(register, register_bcache); 2307 kobj_attribute_write(register_quiet, register_bcache); 2308 kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup); 2309 2310 static bool bch_is_open_backing(struct block_device *bdev) 2311 { 2312 struct cache_set *c, *tc; 2313 struct cached_dev *dc, *t; 2314 2315 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2316 list_for_each_entry_safe(dc, t, &c->cached_devs, list) 2317 if (dc->bdev == bdev) 2318 return true; 2319 list_for_each_entry_safe(dc, t, &uncached_devices, list) 2320 if (dc->bdev == bdev) 2321 return true; 2322 return false; 2323 } 2324 2325 static bool bch_is_open_cache(struct block_device *bdev) 2326 { 2327 struct cache_set *c, *tc; 2328 struct cache *ca; 2329 unsigned int i; 2330 2331 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2332 for_each_cache(ca, c, i) 2333 if (ca->bdev == bdev) 2334 return true; 2335 return false; 2336 } 2337 2338 static bool bch_is_open(struct block_device *bdev) 2339 { 2340 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); 2341 } 2342 2343 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 2344 const char *buffer, size_t size) 2345 { 2346 ssize_t ret = -EINVAL; 2347 const char *err = "cannot allocate memory"; 2348 char *path = NULL; 2349 struct cache_sb *sb = NULL; 2350 struct block_device *bdev = NULL; 2351 struct page *sb_page = NULL; 2352 2353 if (!try_module_get(THIS_MODULE)) 2354 return -EBUSY; 2355 2356 /* For latest state of bcache_is_reboot */ 2357 smp_mb(); 2358 if (bcache_is_reboot) 2359 return -EBUSY; 2360 2361 path = kstrndup(buffer, size, GFP_KERNEL); 2362 if (!path) 2363 goto err; 2364 2365 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); 2366 if (!sb) 2367 goto err; 2368 2369 err = "failed to open device"; 2370 bdev = blkdev_get_by_path(strim(path), 2371 FMODE_READ|FMODE_WRITE|FMODE_EXCL, 2372 sb); 2373 if (IS_ERR(bdev)) { 2374 if (bdev == ERR_PTR(-EBUSY)) { 2375 bdev = lookup_bdev(strim(path)); 2376 mutex_lock(&bch_register_lock); 2377 if (!IS_ERR(bdev) && bch_is_open(bdev)) 2378 err = "device already registered"; 2379 else 2380 err = "device busy"; 2381 mutex_unlock(&bch_register_lock); 2382 if (!IS_ERR(bdev)) 2383 bdput(bdev); 2384 if (attr == &ksysfs_register_quiet) 2385 goto quiet_out; 2386 } 2387 goto err; 2388 } 2389 2390 err = "failed to set blocksize"; 2391 if (set_blocksize(bdev, 4096)) 2392 goto err_close; 2393 2394 err = read_super(sb, bdev, &sb_page); 2395 if (err) 2396 goto err_close; 2397 2398 err = "failed to register device"; 2399 if (SB_IS_BDEV(sb)) { 2400 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); 2401 2402 if (!dc) 2403 goto err_close; 2404 2405 mutex_lock(&bch_register_lock); 2406 ret = register_bdev(sb, sb_page, bdev, dc); 2407 mutex_unlock(&bch_register_lock); 2408 /* blkdev_put() will be called in cached_dev_free() */ 2409 if (ret < 0) 2410 goto err; 2411 } else { 2412 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2413 2414 if (!ca) 2415 goto err_close; 2416 2417 /* blkdev_put() will be called in bch_cache_release() */ 2418 if (register_cache(sb, sb_page, bdev, ca) != 0) 2419 goto err; 2420 } 2421 quiet_out: 2422 ret = size; 2423 out: 2424 if (sb_page) 2425 put_page(sb_page); 2426 kfree(sb); 2427 kfree(path); 2428 module_put(THIS_MODULE); 2429 return ret; 2430 2431 err_close: 2432 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 2433 err: 2434 pr_info("error %s: %s", path, err); 2435 goto out; 2436 } 2437 2438 2439 struct pdev { 2440 struct list_head list; 2441 struct cached_dev *dc; 2442 }; 2443 2444 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k, 2445 struct kobj_attribute *attr, 2446 const char *buffer, 2447 size_t size) 2448 { 2449 LIST_HEAD(pending_devs); 2450 ssize_t ret = size; 2451 struct cached_dev *dc, *tdc; 2452 struct pdev *pdev, *tpdev; 2453 struct cache_set *c, *tc; 2454 2455 mutex_lock(&bch_register_lock); 2456 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) { 2457 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL); 2458 if (!pdev) 2459 break; 2460 pdev->dc = dc; 2461 list_add(&pdev->list, &pending_devs); 2462 } 2463 2464 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) { 2465 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) { 2466 char *pdev_set_uuid = pdev->dc->sb.set_uuid; 2467 char *set_uuid = c->sb.uuid; 2468 2469 if (!memcmp(pdev_set_uuid, set_uuid, 16)) { 2470 list_del(&pdev->list); 2471 kfree(pdev); 2472 break; 2473 } 2474 } 2475 } 2476 mutex_unlock(&bch_register_lock); 2477 2478 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) { 2479 pr_info("delete pdev %p", pdev); 2480 list_del(&pdev->list); 2481 bcache_device_stop(&pdev->dc->disk); 2482 kfree(pdev); 2483 } 2484 2485 return ret; 2486 } 2487 2488 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) 2489 { 2490 if (bcache_is_reboot) 2491 return NOTIFY_DONE; 2492 2493 if (code == SYS_DOWN || 2494 code == SYS_HALT || 2495 code == SYS_POWER_OFF) { 2496 DEFINE_WAIT(wait); 2497 unsigned long start = jiffies; 2498 bool stopped = false; 2499 2500 struct cache_set *c, *tc; 2501 struct cached_dev *dc, *tdc; 2502 2503 mutex_lock(&bch_register_lock); 2504 2505 if (bcache_is_reboot) 2506 goto out; 2507 2508 /* New registration is rejected since now */ 2509 bcache_is_reboot = true; 2510 /* 2511 * Make registering caller (if there is) on other CPU 2512 * core know bcache_is_reboot set to true earlier 2513 */ 2514 smp_mb(); 2515 2516 if (list_empty(&bch_cache_sets) && 2517 list_empty(&uncached_devices)) 2518 goto out; 2519 2520 mutex_unlock(&bch_register_lock); 2521 2522 pr_info("Stopping all devices:"); 2523 2524 /* 2525 * The reason bch_register_lock is not held to call 2526 * bch_cache_set_stop() and bcache_device_stop() is to 2527 * avoid potential deadlock during reboot, because cache 2528 * set or bcache device stopping process will acqurie 2529 * bch_register_lock too. 2530 * 2531 * We are safe here because bcache_is_reboot sets to 2532 * true already, register_bcache() will reject new 2533 * registration now. bcache_is_reboot also makes sure 2534 * bcache_reboot() won't be re-entered on by other thread, 2535 * so there is no race in following list iteration by 2536 * list_for_each_entry_safe(). 2537 */ 2538 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) 2539 bch_cache_set_stop(c); 2540 2541 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) 2542 bcache_device_stop(&dc->disk); 2543 2544 2545 /* 2546 * Give an early chance for other kthreads and 2547 * kworkers to stop themselves 2548 */ 2549 schedule(); 2550 2551 /* What's a condition variable? */ 2552 while (1) { 2553 long timeout = start + 10 * HZ - jiffies; 2554 2555 mutex_lock(&bch_register_lock); 2556 stopped = list_empty(&bch_cache_sets) && 2557 list_empty(&uncached_devices); 2558 2559 if (timeout < 0 || stopped) 2560 break; 2561 2562 prepare_to_wait(&unregister_wait, &wait, 2563 TASK_UNINTERRUPTIBLE); 2564 2565 mutex_unlock(&bch_register_lock); 2566 schedule_timeout(timeout); 2567 } 2568 2569 finish_wait(&unregister_wait, &wait); 2570 2571 if (stopped) 2572 pr_info("All devices stopped"); 2573 else 2574 pr_notice("Timeout waiting for devices to be closed"); 2575 out: 2576 mutex_unlock(&bch_register_lock); 2577 } 2578 2579 return NOTIFY_DONE; 2580 } 2581 2582 static struct notifier_block reboot = { 2583 .notifier_call = bcache_reboot, 2584 .priority = INT_MAX, /* before any real devices */ 2585 }; 2586 2587 static void bcache_exit(void) 2588 { 2589 bch_debug_exit(); 2590 bch_request_exit(); 2591 if (bcache_kobj) 2592 kobject_put(bcache_kobj); 2593 if (bcache_wq) 2594 destroy_workqueue(bcache_wq); 2595 if (bch_journal_wq) 2596 destroy_workqueue(bch_journal_wq); 2597 2598 if (bcache_major) 2599 unregister_blkdev(bcache_major, "bcache"); 2600 unregister_reboot_notifier(&reboot); 2601 mutex_destroy(&bch_register_lock); 2602 } 2603 2604 /* Check and fixup module parameters */ 2605 static void check_module_parameters(void) 2606 { 2607 if (bch_cutoff_writeback_sync == 0) 2608 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC; 2609 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) { 2610 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u", 2611 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX); 2612 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX; 2613 } 2614 2615 if (bch_cutoff_writeback == 0) 2616 bch_cutoff_writeback = CUTOFF_WRITEBACK; 2617 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) { 2618 pr_warn("set bch_cutoff_writeback (%u) to max value %u", 2619 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX); 2620 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX; 2621 } 2622 2623 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) { 2624 pr_warn("set bch_cutoff_writeback (%u) to %u", 2625 bch_cutoff_writeback, bch_cutoff_writeback_sync); 2626 bch_cutoff_writeback = bch_cutoff_writeback_sync; 2627 } 2628 } 2629 2630 static int __init bcache_init(void) 2631 { 2632 static const struct attribute *files[] = { 2633 &ksysfs_register.attr, 2634 &ksysfs_register_quiet.attr, 2635 &ksysfs_pendings_cleanup.attr, 2636 NULL 2637 }; 2638 2639 check_module_parameters(); 2640 2641 mutex_init(&bch_register_lock); 2642 init_waitqueue_head(&unregister_wait); 2643 register_reboot_notifier(&reboot); 2644 2645 bcache_major = register_blkdev(0, "bcache"); 2646 if (bcache_major < 0) { 2647 unregister_reboot_notifier(&reboot); 2648 mutex_destroy(&bch_register_lock); 2649 return bcache_major; 2650 } 2651 2652 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); 2653 if (!bcache_wq) 2654 goto err; 2655 2656 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); 2657 if (!bch_journal_wq) 2658 goto err; 2659 2660 bcache_kobj = kobject_create_and_add("bcache", fs_kobj); 2661 if (!bcache_kobj) 2662 goto err; 2663 2664 if (bch_request_init() || 2665 sysfs_create_files(bcache_kobj, files)) 2666 goto err; 2667 2668 bch_debug_init(); 2669 closure_debug_init(); 2670 2671 bcache_is_reboot = false; 2672 2673 return 0; 2674 err: 2675 bcache_exit(); 2676 return -ENOMEM; 2677 } 2678 2679 /* 2680 * Module hooks 2681 */ 2682 module_exit(bcache_exit); 2683 module_init(bcache_init); 2684 2685 module_param(bch_cutoff_writeback, uint, 0); 2686 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback"); 2687 2688 module_param(bch_cutoff_writeback_sync, uint, 0); 2689 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback"); 2690 2691 MODULE_DESCRIPTION("Bcache: a Linux block layer cache"); 2692 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>"); 2693 MODULE_LICENSE("GPL"); 2694