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#include "features.h"
  17
  18#include <linux/blkdev.h>
  19#include <linux/debugfs.h>
  20#include <linux/genhd.h>
  21#include <linux/idr.h>
  22#include <linux/kthread.h>
  23#include <linux/workqueue.h>
  24#include <linux/module.h>
  25#include <linux/random.h>
  26#include <linux/reboot.h>
  27#include <linux/sysfs.h>
  28
  29unsigned int bch_cutoff_writeback;
  30unsigned int bch_cutoff_writeback_sync;
  31
  32static const char bcache_magic[] = {
  33	0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
  34	0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
  35};
  36
  37static const char invalid_uuid[] = {
  38	0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
  39	0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
  40};
  41
  42static struct kobject *bcache_kobj;
  43struct mutex bch_register_lock;
  44bool bcache_is_reboot;
  45LIST_HEAD(bch_cache_sets);
  46static LIST_HEAD(uncached_devices);
  47
  48static int bcache_major;
  49static DEFINE_IDA(bcache_device_idx);
  50static wait_queue_head_t unregister_wait;
  51struct workqueue_struct *bcache_wq;
  52struct workqueue_struct *bch_journal_wq;
  53
  54
  55#define BTREE_MAX_PAGES		(256 * 1024 / PAGE_SIZE)
  56/* limitation of partitions number on single bcache device */
  57#define BCACHE_MINORS		128
  58/* limitation of bcache devices number on single system */
  59#define BCACHE_DEVICE_IDX_MAX	((1U << MINORBITS)/BCACHE_MINORS)
  60
  61/* Superblock */
  62
  63static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s)
  64{
  65	unsigned int bucket_size = le16_to_cpu(s->bucket_size);
  66
  67	if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES &&
  68	     bch_has_feature_large_bucket(sb))
  69		bucket_size |= le16_to_cpu(s->bucket_size_hi) << 16;
  70
  71	return bucket_size;
  72}
  73
  74static const char *read_super_common(struct cache_sb *sb,  struct block_device *bdev,
  75				     struct cache_sb_disk *s)
  76{
  77	const char *err;
  78	unsigned int i;
  79
  80	sb->first_bucket= le16_to_cpu(s->first_bucket);
  81	sb->nbuckets	= le64_to_cpu(s->nbuckets);
  82	sb->bucket_size	= get_bucket_size(sb, s);
  83
  84	sb->nr_in_set	= le16_to_cpu(s->nr_in_set);
  85	sb->nr_this_dev	= le16_to_cpu(s->nr_this_dev);
  86
  87	err = "Too many journal buckets";
  88	if (sb->keys > SB_JOURNAL_BUCKETS)
  89		goto err;
  90
  91	err = "Too many buckets";
  92	if (sb->nbuckets > LONG_MAX)
  93		goto err;
  94
  95	err = "Not enough buckets";
  96	if (sb->nbuckets < 1 << 7)
  97		goto err;
  98
  99	err = "Bad block size (not power of 2)";
 100	if (!is_power_of_2(sb->block_size))
 101		goto err;
 102
 103	err = "Bad block size (larger than page size)";
 104	if (sb->block_size > PAGE_SECTORS)
 105		goto err;
 106
 107	err = "Bad bucket size (not power of 2)";
 108	if (!is_power_of_2(sb->bucket_size))
 109		goto err;
 110
 111	err = "Bad bucket size (smaller than page size)";
 112	if (sb->bucket_size < PAGE_SECTORS)
 113		goto err;
 114
 115	err = "Invalid superblock: device too small";
 116	if (get_capacity(bdev->bd_disk) <
 117	    sb->bucket_size * sb->nbuckets)
 118		goto err;
 119
 120	err = "Bad UUID";
 121	if (bch_is_zero(sb->set_uuid, 16))
 122		goto err;
 123
 124	err = "Bad cache device number in set";
 125	if (!sb->nr_in_set ||
 126	    sb->nr_in_set <= sb->nr_this_dev ||
 127	    sb->nr_in_set > MAX_CACHES_PER_SET)
 128		goto err;
 129
 130	err = "Journal buckets not sequential";
 131	for (i = 0; i < sb->keys; i++)
 132		if (sb->d[i] != sb->first_bucket + i)
 133			goto err;
 134
 135	err = "Too many journal buckets";
 136	if (sb->first_bucket + sb->keys > sb->nbuckets)
 137		goto err;
 138
 139	err = "Invalid superblock: first bucket comes before end of super";
 140	if (sb->first_bucket * sb->bucket_size < 16)
 141		goto err;
 142
 143	err = NULL;
 144err:
 145	return err;
 146}
 147
 148
 149static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
 150			      struct cache_sb_disk **res)
 151{
 152	const char *err;
 153	struct cache_sb_disk *s;
 154	struct page *page;
 155	unsigned int i;
 156
 157	page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
 158				   SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
 159	if (IS_ERR(page))
 160		return "IO error";
 161	s = page_address(page) + offset_in_page(SB_OFFSET);
 162
 163	sb->offset		= le64_to_cpu(s->offset);
 164	sb->version		= le64_to_cpu(s->version);
 165
 166	memcpy(sb->magic,	s->magic, 16);
 167	memcpy(sb->uuid,	s->uuid, 16);
 168	memcpy(sb->set_uuid,	s->set_uuid, 16);
 169	memcpy(sb->label,	s->label, SB_LABEL_SIZE);
 170
 171	sb->flags		= le64_to_cpu(s->flags);
 172	sb->seq			= le64_to_cpu(s->seq);
 173	sb->last_mount		= le32_to_cpu(s->last_mount);
 174	sb->keys		= le16_to_cpu(s->keys);
 175
 176	for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
 177		sb->d[i] = le64_to_cpu(s->d[i]);
 178
 179	pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u\n",
 180		 sb->version, sb->flags, sb->seq, sb->keys);
 181
 182	err = "Not a bcache superblock (bad offset)";
 183	if (sb->offset != SB_SECTOR)
 184		goto err;
 185
 186	err = "Not a bcache superblock (bad magic)";
 187	if (memcmp(sb->magic, bcache_magic, 16))
 188		goto err;
 189
 190	err = "Bad checksum";
 191	if (s->csum != csum_set(s))
 192		goto err;
 193
 194	err = "Bad UUID";
 195	if (bch_is_zero(sb->uuid, 16))
 196		goto err;
 197
 198	sb->block_size	= le16_to_cpu(s->block_size);
 199
 200	err = "Superblock block size smaller than device block size";
 201	if (sb->block_size << 9 < bdev_logical_block_size(bdev))
 202		goto err;
 203
 204	switch (sb->version) {
 205	case BCACHE_SB_VERSION_BDEV:
 206		sb->data_offset	= BDEV_DATA_START_DEFAULT;
 207		break;
 208	case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
 209	case BCACHE_SB_VERSION_BDEV_WITH_FEATURES:
 210		sb->data_offset	= le64_to_cpu(s->data_offset);
 211
 212		err = "Bad data offset";
 213		if (sb->data_offset < BDEV_DATA_START_DEFAULT)
 214			goto err;
 215
 216		break;
 217	case BCACHE_SB_VERSION_CDEV:
 218	case BCACHE_SB_VERSION_CDEV_WITH_UUID:
 219		err = read_super_common(sb, bdev, s);
 220		if (err)
 221			goto err;
 222		break;
 223	case BCACHE_SB_VERSION_CDEV_WITH_FEATURES:
 224		/*
 225		 * Feature bits are needed in read_super_common(),
 226		 * convert them firstly.
 227		 */
 228		sb->feature_compat = le64_to_cpu(s->feature_compat);
 229		sb->feature_incompat = le64_to_cpu(s->feature_incompat);
 230		sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat);
 231		err = read_super_common(sb, bdev, s);
 232		if (err)
 233			goto err;
 234		break;
 235	default:
 236		err = "Unsupported superblock version";
 237		goto err;
 238	}
 239
 240	sb->last_mount = (u32)ktime_get_real_seconds();
 241	*res = s;
 242	return NULL;
 243err:
 244	put_page(page);
 245	return err;
 246}
 247
 248static void write_bdev_super_endio(struct bio *bio)
 249{
 250	struct cached_dev *dc = bio->bi_private;
 251
 252	if (bio->bi_status)
 253		bch_count_backing_io_errors(dc, bio);
 254
 255	closure_put(&dc->sb_write);
 256}
 257
 258static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
 259		struct bio *bio)
 260{
 261	unsigned int i;
 262
 263	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
 264	bio->bi_iter.bi_sector	= SB_SECTOR;
 265	__bio_add_page(bio, virt_to_page(out), SB_SIZE,
 266			offset_in_page(out));
 267
 268	out->offset		= cpu_to_le64(sb->offset);
 269
 270	memcpy(out->uuid,	sb->uuid, 16);
 271	memcpy(out->set_uuid,	sb->set_uuid, 16);
 272	memcpy(out->label,	sb->label, SB_LABEL_SIZE);
 273
 274	out->flags		= cpu_to_le64(sb->flags);
 275	out->seq		= cpu_to_le64(sb->seq);
 276
 277	out->last_mount		= cpu_to_le32(sb->last_mount);
 278	out->first_bucket	= cpu_to_le16(sb->first_bucket);
 279	out->keys		= cpu_to_le16(sb->keys);
 280
 281	for (i = 0; i < sb->keys; i++)
 282		out->d[i] = cpu_to_le64(sb->d[i]);
 283
 284	if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
 285		out->feature_compat    = cpu_to_le64(sb->feature_compat);
 286		out->feature_incompat  = cpu_to_le64(sb->feature_incompat);
 287		out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
 288	}
 289
 290	out->version		= cpu_to_le64(sb->version);
 291	out->csum = csum_set(out);
 292
 293	pr_debug("ver %llu, flags %llu, seq %llu\n",
 294		 sb->version, sb->flags, sb->seq);
 295
 296	submit_bio(bio);
 297}
 298
 299static void bch_write_bdev_super_unlock(struct closure *cl)
 300{
 301	struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
 302
 303	up(&dc->sb_write_mutex);
 304}
 305
 306void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
 307{
 308	struct closure *cl = &dc->sb_write;
 309	struct bio *bio = &dc->sb_bio;
 310
 311	down(&dc->sb_write_mutex);
 312	closure_init(cl, parent);
 313
 314	bio_init(bio, dc->sb_bv, 1);
 315	bio_set_dev(bio, dc->bdev);
 316	bio->bi_end_io	= write_bdev_super_endio;
 317	bio->bi_private = dc;
 318
 319	closure_get(cl);
 320	/* I/O request sent to backing device */
 321	__write_super(&dc->sb, dc->sb_disk, bio);
 322
 323	closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
 324}
 325
 326static void write_super_endio(struct bio *bio)
 327{
 328	struct cache *ca = bio->bi_private;
 329
 330	/* is_read = 0 */
 331	bch_count_io_errors(ca, bio->bi_status, 0,
 332			    "writing superblock");
 333	closure_put(&ca->set->sb_write);
 334}
 335
 336static void bcache_write_super_unlock(struct closure *cl)
 337{
 338	struct cache_set *c = container_of(cl, struct cache_set, sb_write);
 339
 340	up(&c->sb_write_mutex);
 341}
 342
 343void bcache_write_super(struct cache_set *c)
 344{
 345	struct closure *cl = &c->sb_write;
 346	struct cache *ca;
 347	unsigned int i, version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
 348
 349	down(&c->sb_write_mutex);
 350	closure_init(cl, &c->cl);
 351
 352	c->sb.seq++;
 353
 354	if (c->sb.version > version)
 355		version = c->sb.version;
 356
 357	for_each_cache(ca, c, i) {
 358		struct bio *bio = &ca->sb_bio;
 359
 360		ca->sb.version		= version;
 361		ca->sb.seq		= c->sb.seq;
 362		ca->sb.last_mount	= c->sb.last_mount;
 363
 364		SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
 365
 366		bio_init(bio, ca->sb_bv, 1);
 367		bio_set_dev(bio, ca->bdev);
 368		bio->bi_end_io	= write_super_endio;
 369		bio->bi_private = ca;
 370
 371		closure_get(cl);
 372		__write_super(&ca->sb, ca->sb_disk, bio);
 373	}
 374
 375	closure_return_with_destructor(cl, bcache_write_super_unlock);
 376}
 377
 378/* UUID io */
 379
 380static void uuid_endio(struct bio *bio)
 381{
 382	struct closure *cl = bio->bi_private;
 383	struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
 384
 385	cache_set_err_on(bio->bi_status, c, "accessing uuids");
 386	bch_bbio_free(bio, c);
 387	closure_put(cl);
 388}
 389
 390static void uuid_io_unlock(struct closure *cl)
 391{
 392	struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
 393
 394	up(&c->uuid_write_mutex);
 395}
 396
 397static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
 398		    struct bkey *k, struct closure *parent)
 399{
 400	struct closure *cl = &c->uuid_write;
 401	struct uuid_entry *u;
 402	unsigned int i;
 403	char buf[80];
 404
 405	BUG_ON(!parent);
 406	down(&c->uuid_write_mutex);
 407	closure_init(cl, parent);
 408
 409	for (i = 0; i < KEY_PTRS(k); i++) {
 410		struct bio *bio = bch_bbio_alloc(c);
 411
 412		bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
 413		bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
 414
 415		bio->bi_end_io	= uuid_endio;
 416		bio->bi_private = cl;
 417		bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
 418		bch_bio_map(bio, c->uuids);
 419
 420		bch_submit_bbio(bio, c, k, i);
 421
 422		if (op != REQ_OP_WRITE)
 423			break;
 424	}
 425
 426	bch_extent_to_text(buf, sizeof(buf), k);
 427	pr_debug("%s UUIDs at %s\n", op == REQ_OP_WRITE ? "wrote" : "read", buf);
 428
 429	for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
 430		if (!bch_is_zero(u->uuid, 16))
 431			pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
 432				 u - c->uuids, u->uuid, u->label,
 433				 u->first_reg, u->last_reg, u->invalidated);
 434
 435	closure_return_with_destructor(cl, uuid_io_unlock);
 436}
 437
 438static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
 439{
 440	struct bkey *k = &j->uuid_bucket;
 441
 442	if (__bch_btree_ptr_invalid(c, k))
 443		return "bad uuid pointer";
 444
 445	bkey_copy(&c->uuid_bucket, k);
 446	uuid_io(c, REQ_OP_READ, 0, k, cl);
 447
 448	if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
 449		struct uuid_entry_v0	*u0 = (void *) c->uuids;
 450		struct uuid_entry	*u1 = (void *) c->uuids;
 451		int i;
 452
 453		closure_sync(cl);
 454
 455		/*
 456		 * Since the new uuid entry is bigger than the old, we have to
 457		 * convert starting at the highest memory address and work down
 458		 * in order to do it in place
 459		 */
 460
 461		for (i = c->nr_uuids - 1;
 462		     i >= 0;
 463		     --i) {
 464			memcpy(u1[i].uuid,	u0[i].uuid, 16);
 465			memcpy(u1[i].label,	u0[i].label, 32);
 466
 467			u1[i].first_reg		= u0[i].first_reg;
 468			u1[i].last_reg		= u0[i].last_reg;
 469			u1[i].invalidated	= u0[i].invalidated;
 470
 471			u1[i].flags	= 0;
 472			u1[i].sectors	= 0;
 473		}
 474	}
 475
 476	return NULL;
 477}
 478
 479static int __uuid_write(struct cache_set *c)
 480{
 481	BKEY_PADDED(key) k;
 482	struct closure cl;
 483	struct cache *ca;
 484	unsigned int size;
 485
 486	closure_init_stack(&cl);
 487	lockdep_assert_held(&bch_register_lock);
 488
 489	if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
 490		return 1;
 491
 492	size =  meta_bucket_pages(&c->sb) * PAGE_SECTORS;
 493	SET_KEY_SIZE(&k.key, size);
 494	uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
 495	closure_sync(&cl);
 496
 497	/* Only one bucket used for uuid write */
 498	ca = PTR_CACHE(c, &k.key, 0);
 499	atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
 500
 501	bkey_copy(&c->uuid_bucket, &k.key);
 502	bkey_put(c, &k.key);
 503	return 0;
 504}
 505
 506int bch_uuid_write(struct cache_set *c)
 507{
 508	int ret = __uuid_write(c);
 509
 510	if (!ret)
 511		bch_journal_meta(c, NULL);
 512
 513	return ret;
 514}
 515
 516static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
 517{
 518	struct uuid_entry *u;
 519
 520	for (u = c->uuids;
 521	     u < c->uuids + c->nr_uuids; u++)
 522		if (!memcmp(u->uuid, uuid, 16))
 523			return u;
 524
 525	return NULL;
 526}
 527
 528static struct uuid_entry *uuid_find_empty(struct cache_set *c)
 529{
 530	static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
 531
 532	return uuid_find(c, zero_uuid);
 533}
 534
 535/*
 536 * Bucket priorities/gens:
 537 *
 538 * For each bucket, we store on disk its
 539 *   8 bit gen
 540 *  16 bit priority
 541 *
 542 * See alloc.c for an explanation of the gen. The priority is used to implement
 543 * lru (and in the future other) cache replacement policies; for most purposes
 544 * it's just an opaque integer.
 545 *
 546 * The gens and the priorities don't have a whole lot to do with each other, and
 547 * it's actually the gens that must be written out at specific times - it's no
 548 * big deal if the priorities don't get written, if we lose them we just reuse
 549 * buckets in suboptimal order.
 550 *
 551 * On disk they're stored in a packed array, and in as many buckets are required
 552 * to fit them all. The buckets we use to store them form a list; the journal
 553 * header points to the first bucket, the first bucket points to the second
 554 * bucket, et cetera.
 555 *
 556 * This code is used by the allocation code; periodically (whenever it runs out
 557 * of buckets to allocate from) the allocation code will invalidate some
 558 * buckets, but it can't use those buckets until their new gens are safely on
 559 * disk.
 560 */
 561
 562static void prio_endio(struct bio *bio)
 563{
 564	struct cache *ca = bio->bi_private;
 565
 566	cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
 567	bch_bbio_free(bio, ca->set);
 568	closure_put(&ca->prio);
 569}
 570
 571static void prio_io(struct cache *ca, uint64_t bucket, int op,
 572		    unsigned long op_flags)
 573{
 574	struct closure *cl = &ca->prio;
 575	struct bio *bio = bch_bbio_alloc(ca->set);
 576
 577	closure_init_stack(cl);
 578
 579	bio->bi_iter.bi_sector	= bucket * ca->sb.bucket_size;
 580	bio_set_dev(bio, ca->bdev);
 581	bio->bi_iter.bi_size	= meta_bucket_bytes(&ca->sb);
 582
 583	bio->bi_end_io	= prio_endio;
 584	bio->bi_private = ca;
 585	bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
 586	bch_bio_map(bio, ca->disk_buckets);
 587
 588	closure_bio_submit(ca->set, bio, &ca->prio);
 589	closure_sync(cl);
 590}
 591
 592int bch_prio_write(struct cache *ca, bool wait)
 593{
 594	int i;
 595	struct bucket *b;
 596	struct closure cl;
 597
 598	pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n",
 599		 fifo_used(&ca->free[RESERVE_PRIO]),
 600		 fifo_used(&ca->free[RESERVE_NONE]),
 601		 fifo_used(&ca->free_inc));
 602
 603	/*
 604	 * Pre-check if there are enough free buckets. In the non-blocking
 605	 * scenario it's better to fail early rather than starting to allocate
 606	 * buckets and do a cleanup later in case of failure.
 607	 */
 608	if (!wait) {
 609		size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
 610			       fifo_used(&ca->free[RESERVE_NONE]);
 611		if (prio_buckets(ca) > avail)
 612			return -ENOMEM;
 613	}
 614
 615	closure_init_stack(&cl);
 616
 617	lockdep_assert_held(&ca->set->bucket_lock);
 618
 619	ca->disk_buckets->seq++;
 620
 621	atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
 622			&ca->meta_sectors_written);
 623
 624	for (i = prio_buckets(ca) - 1; i >= 0; --i) {
 625		long bucket;
 626		struct prio_set *p = ca->disk_buckets;
 627		struct bucket_disk *d = p->data;
 628		struct bucket_disk *end = d + prios_per_bucket(ca);
 629
 630		for (b = ca->buckets + i * prios_per_bucket(ca);
 631		     b < ca->buckets + ca->sb.nbuckets && d < end;
 632		     b++, d++) {
 633			d->prio = cpu_to_le16(b->prio);
 634			d->gen = b->gen;
 635		}
 636
 637		p->next_bucket	= ca->prio_buckets[i + 1];
 638		p->magic	= pset_magic(&ca->sb);
 639		p->csum		= bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8);
 640
 641		bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
 642		BUG_ON(bucket == -1);
 643
 644		mutex_unlock(&ca->set->bucket_lock);
 645		prio_io(ca, bucket, REQ_OP_WRITE, 0);
 646		mutex_lock(&ca->set->bucket_lock);
 647
 648		ca->prio_buckets[i] = bucket;
 649		atomic_dec_bug(&ca->buckets[bucket].pin);
 650	}
 651
 652	mutex_unlock(&ca->set->bucket_lock);
 653
 654	bch_journal_meta(ca->set, &cl);
 655	closure_sync(&cl);
 656
 657	mutex_lock(&ca->set->bucket_lock);
 658
 659	/*
 660	 * Don't want the old priorities to get garbage collected until after we
 661	 * finish writing the new ones, and they're journalled
 662	 */
 663	for (i = 0; i < prio_buckets(ca); i++) {
 664		if (ca->prio_last_buckets[i])
 665			__bch_bucket_free(ca,
 666				&ca->buckets[ca->prio_last_buckets[i]]);
 667
 668		ca->prio_last_buckets[i] = ca->prio_buckets[i];
 669	}
 670	return 0;
 671}
 672
 673static int prio_read(struct cache *ca, uint64_t bucket)
 674{
 675	struct prio_set *p = ca->disk_buckets;
 676	struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
 677	struct bucket *b;
 678	unsigned int bucket_nr = 0;
 679	int ret = -EIO;
 680
 681	for (b = ca->buckets;
 682	     b < ca->buckets + ca->sb.nbuckets;
 683	     b++, d++) {
 684		if (d == end) {
 685			ca->prio_buckets[bucket_nr] = bucket;
 686			ca->prio_last_buckets[bucket_nr] = bucket;
 687			bucket_nr++;
 688
 689			prio_io(ca, bucket, REQ_OP_READ, 0);
 690
 691			if (p->csum !=
 692			    bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) {
 693				pr_warn("bad csum reading priorities\n");
 694				goto out;
 695			}
 696
 697			if (p->magic != pset_magic(&ca->sb)) {
 698				pr_warn("bad magic reading priorities\n");
 699				goto out;
 700			}
 701
 702			bucket = p->next_bucket;
 703			d = p->data;
 704		}
 705
 706		b->prio = le16_to_cpu(d->prio);
 707		b->gen = b->last_gc = d->gen;
 708	}
 709
 710	ret = 0;
 711out:
 712	return ret;
 713}
 714
 715/* Bcache device */
 716
 717static int open_dev(struct block_device *b, fmode_t mode)
 718{
 719	struct bcache_device *d = b->bd_disk->private_data;
 720
 721	if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
 722		return -ENXIO;
 723
 724	closure_get(&d->cl);
 725	return 0;
 726}
 727
 728static void release_dev(struct gendisk *b, fmode_t mode)
 729{
 730	struct bcache_device *d = b->private_data;
 731
 732	closure_put(&d->cl);
 733}
 734
 735static int ioctl_dev(struct block_device *b, fmode_t mode,
 736		     unsigned int cmd, unsigned long arg)
 737{
 738	struct bcache_device *d = b->bd_disk->private_data;
 739
 740	return d->ioctl(d, mode, cmd, arg);
 741}
 742
 743static const struct block_device_operations bcache_cached_ops = {
 744	.submit_bio	= cached_dev_submit_bio,
 745	.open		= open_dev,
 746	.release	= release_dev,
 747	.ioctl		= ioctl_dev,
 748	.owner		= THIS_MODULE,
 749};
 750
 751static const struct block_device_operations bcache_flash_ops = {
 752	.submit_bio	= flash_dev_submit_bio,
 753	.open		= open_dev,
 754	.release	= release_dev,
 755	.ioctl		= ioctl_dev,
 756	.owner		= THIS_MODULE,
 757};
 758
 759void bcache_device_stop(struct bcache_device *d)
 760{
 761	if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
 762		/*
 763		 * closure_fn set to
 764		 * - cached device: cached_dev_flush()
 765		 * - flash dev: flash_dev_flush()
 766		 */
 767		closure_queue(&d->cl);
 768}
 769
 770static void bcache_device_unlink(struct bcache_device *d)
 771{
 772	lockdep_assert_held(&bch_register_lock);
 773
 774	if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
 775		unsigned int i;
 776		struct cache *ca;
 777
 778		sysfs_remove_link(&d->c->kobj, d->name);
 779		sysfs_remove_link(&d->kobj, "cache");
 780
 781		for_each_cache(ca, d->c, i)
 782			bd_unlink_disk_holder(ca->bdev, d->disk);
 783	}
 784}
 785
 786static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
 787			       const char *name)
 788{
 789	unsigned int i;
 790	struct cache *ca;
 791	int ret;
 792
 793	for_each_cache(ca, d->c, i)
 794		bd_link_disk_holder(ca->bdev, d->disk);
 795
 796	snprintf(d->name, BCACHEDEVNAME_SIZE,
 797		 "%s%u", name, d->id);
 798
 799	ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
 800	if (ret < 0)
 801		pr_err("Couldn't create device -> cache set symlink\n");
 802
 803	ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
 804	if (ret < 0)
 805		pr_err("Couldn't create cache set -> device symlink\n");
 806
 807	clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
 808}
 809
 810static void bcache_device_detach(struct bcache_device *d)
 811{
 812	lockdep_assert_held(&bch_register_lock);
 813
 814	atomic_dec(&d->c->attached_dev_nr);
 815
 816	if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
 817		struct uuid_entry *u = d->c->uuids + d->id;
 818
 819		SET_UUID_FLASH_ONLY(u, 0);
 820		memcpy(u->uuid, invalid_uuid, 16);
 821		u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
 822		bch_uuid_write(d->c);
 823	}
 824
 825	bcache_device_unlink(d);
 826
 827	d->c->devices[d->id] = NULL;
 828	closure_put(&d->c->caching);
 829	d->c = NULL;
 830}
 831
 832static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
 833				 unsigned int id)
 834{
 835	d->id = id;
 836	d->c = c;
 837	c->devices[id] = d;
 838
 839	if (id >= c->devices_max_used)
 840		c->devices_max_used = id + 1;
 841
 842	closure_get(&c->caching);
 843}
 844
 845static inline int first_minor_to_idx(int first_minor)
 846{
 847	return (first_minor/BCACHE_MINORS);
 848}
 849
 850static inline int idx_to_first_minor(int idx)
 851{
 852	return (idx * BCACHE_MINORS);
 853}
 854
 855static void bcache_device_free(struct bcache_device *d)
 856{
 857	struct gendisk *disk = d->disk;
 858
 859	lockdep_assert_held(&bch_register_lock);
 860
 861	if (disk)
 862		pr_info("%s stopped\n", disk->disk_name);
 863	else
 864		pr_err("bcache device (NULL gendisk) stopped\n");
 865
 866	if (d->c)
 867		bcache_device_detach(d);
 868
 869	if (disk) {
 870		bool disk_added = (disk->flags & GENHD_FL_UP) != 0;
 871
 872		if (disk_added)
 873			del_gendisk(disk);
 874
 875		if (disk->queue)
 876			blk_cleanup_queue(disk->queue);
 877
 878		ida_simple_remove(&bcache_device_idx,
 879				  first_minor_to_idx(disk->first_minor));
 880		if (disk_added)
 881			put_disk(disk);
 882	}
 883
 884	bioset_exit(&d->bio_split);
 885	kvfree(d->full_dirty_stripes);
 886	kvfree(d->stripe_sectors_dirty);
 887
 888	closure_debug_destroy(&d->cl);
 889}
 890
 891static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
 892		sector_t sectors, struct block_device *cached_bdev,
 893		const struct block_device_operations *ops)
 894{
 895	struct request_queue *q;
 896	const size_t max_stripes = min_t(size_t, INT_MAX,
 897					 SIZE_MAX / sizeof(atomic_t));
 898	uint64_t n;
 899	int idx;
 900
 901	if (!d->stripe_size)
 902		d->stripe_size = 1 << 31;
 903
 904	n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
 905	if (!n || n > max_stripes) {
 906		pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
 907			n);
 908		return -ENOMEM;
 909	}
 910	d->nr_stripes = n;
 911
 912	n = d->nr_stripes * sizeof(atomic_t);
 913	d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
 914	if (!d->stripe_sectors_dirty)
 915		return -ENOMEM;
 916
 917	n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
 918	d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
 919	if (!d->full_dirty_stripes)
 920		return -ENOMEM;
 921
 922	idx = ida_simple_get(&bcache_device_idx, 0,
 923				BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
 924	if (idx < 0)
 925		return idx;
 926
 927	if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
 928			BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
 929		goto err;
 930
 931	d->disk = alloc_disk(BCACHE_MINORS);
 932	if (!d->disk)
 933		goto err;
 934
 935	set_capacity(d->disk, sectors);
 936	snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
 937
 938	d->disk->major		= bcache_major;
 939	d->disk->first_minor	= idx_to_first_minor(idx);
 940	d->disk->fops		= ops;
 941	d->disk->private_data	= d;
 942
 943	q = blk_alloc_queue(NUMA_NO_NODE);
 944	if (!q)
 945		return -ENOMEM;
 946
 947	d->disk->queue			= q;
 948	q->limits.max_hw_sectors	= UINT_MAX;
 949	q->limits.max_sectors		= UINT_MAX;
 950	q->limits.max_segment_size	= UINT_MAX;
 951	q->limits.max_segments		= BIO_MAX_PAGES;
 952	blk_queue_max_discard_sectors(q, UINT_MAX);
 953	q->limits.discard_granularity	= 512;
 954	q->limits.io_min		= block_size;
 955	q->limits.logical_block_size	= block_size;
 956	q->limits.physical_block_size	= block_size;
 957
 958	if (q->limits.logical_block_size > PAGE_SIZE && cached_bdev) {
 959		/*
 960		 * This should only happen with BCACHE_SB_VERSION_BDEV.
 961		 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
 962		 */
 963		pr_info("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
 964			d->disk->disk_name, q->limits.logical_block_size,
 965			PAGE_SIZE, bdev_logical_block_size(cached_bdev));
 966
 967		/* This also adjusts physical block size/min io size if needed */
 968		blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev));
 969	}
 970
 971	blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
 972	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
 973	blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
 974
 975	blk_queue_write_cache(q, true, true);
 976
 977	return 0;
 978
 979err:
 980	ida_simple_remove(&bcache_device_idx, idx);
 981	return -ENOMEM;
 982
 983}
 984
 985/* Cached device */
 986
 987static void calc_cached_dev_sectors(struct cache_set *c)
 988{
 989	uint64_t sectors = 0;
 990	struct cached_dev *dc;
 991
 992	list_for_each_entry(dc, &c->cached_devs, list)
 993		sectors += bdev_sectors(dc->bdev);
 994
 995	c->cached_dev_sectors = sectors;
 996}
 997
 998#define BACKING_DEV_OFFLINE_TIMEOUT 5
 999static int cached_dev_status_update(void *arg)
1000{
1001	struct cached_dev *dc = arg;
1002	struct request_queue *q;
1003
1004	/*
1005	 * If this delayed worker is stopping outside, directly quit here.
1006	 * dc->io_disable might be set via sysfs interface, so check it
1007	 * here too.
1008	 */
1009	while (!kthread_should_stop() && !dc->io_disable) {
1010		q = bdev_get_queue(dc->bdev);
1011		if (blk_queue_dying(q))
1012			dc->offline_seconds++;
1013		else
1014			dc->offline_seconds = 0;
1015
1016		if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1017			pr_err("%s: device offline for %d seconds\n",
1018			       dc->backing_dev_name,
1019			       BACKING_DEV_OFFLINE_TIMEOUT);
1020			pr_err("%s: disable I/O request due to backing device offline\n",
1021			       dc->disk.name);
1022			dc->io_disable = true;
1023			/* let others know earlier that io_disable is true */
1024			smp_mb();
1025			bcache_device_stop(&dc->disk);
1026			break;
1027		}
1028		schedule_timeout_interruptible(HZ);
1029	}
1030
1031	wait_for_kthread_stop();
1032	return 0;
1033}
1034
1035
1036int bch_cached_dev_run(struct cached_dev *dc)
1037{
1038	struct bcache_device *d = &dc->disk;
1039	char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1040	char *env[] = {
1041		"DRIVER=bcache",
1042		kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1043		kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1044		NULL,
1045	};
1046
1047	if (dc->io_disable) {
1048		pr_err("I/O disabled on cached dev %s\n",
1049		       dc->backing_dev_name);
1050		kfree(env[1]);
1051		kfree(env[2]);
1052		kfree(buf);
1053		return -EIO;
1054	}
1055
1056	if (atomic_xchg(&dc->running, 1)) {
1057		kfree(env[1]);
1058		kfree(env[2]);
1059		kfree(buf);
1060		pr_info("cached dev %s is running already\n",
1061		       dc->backing_dev_name);
1062		return -EBUSY;
1063	}
1064
1065	if (!d->c &&
1066	    BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1067		struct closure cl;
1068
1069		closure_init_stack(&cl);
1070
1071		SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1072		bch_write_bdev_super(dc, &cl);
1073		closure_sync(&cl);
1074	}
1075
1076	add_disk(d->disk);
1077	bd_link_disk_holder(dc->bdev, dc->disk.disk);
1078	/*
1079	 * won't show up in the uevent file, use udevadm monitor -e instead
1080	 * only class / kset properties are persistent
1081	 */
1082	kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1083	kfree(env[1]);
1084	kfree(env[2]);
1085	kfree(buf);
1086
1087	if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1088	    sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1089			      &d->kobj, "bcache")) {
1090		pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1091		return -ENOMEM;
1092	}
1093
1094	dc->status_update_thread = kthread_run(cached_dev_status_update,
1095					       dc, "bcache_status_update");
1096	if (IS_ERR(dc->status_update_thread)) {
1097		pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1098	}
1099
1100	return 0;
1101}
1102
1103/*
1104 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1105 * work dc->writeback_rate_update is running. Wait until the routine
1106 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1107 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1108 * seconds, give up waiting here and continue to cancel it too.
1109 */
1110static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1111{
1112	int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1113
1114	do {
1115		if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1116			      &dc->disk.flags))
1117			break;
1118		time_out--;
1119		schedule_timeout_interruptible(1);
1120	} while (time_out > 0);
1121
1122	if (time_out == 0)
1123		pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1124
1125	cancel_delayed_work_sync(&dc->writeback_rate_update);
1126}
1127
1128static void cached_dev_detach_finish(struct work_struct *w)
1129{
1130	struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1131	struct closure cl;
1132
1133	closure_init_stack(&cl);
1134
1135	BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1136	BUG_ON(refcount_read(&dc->count));
1137
1138
1139	if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1140		cancel_writeback_rate_update_dwork(dc);
1141
1142	if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1143		kthread_stop(dc->writeback_thread);
1144		dc->writeback_thread = NULL;
1145	}
1146
1147	memset(&dc->sb.set_uuid, 0, 16);
1148	SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
1149
1150	bch_write_bdev_super(dc, &cl);
1151	closure_sync(&cl);
1152
1153	mutex_lock(&bch_register_lock);
1154
1155	calc_cached_dev_sectors(dc->disk.c);
1156	bcache_device_detach(&dc->disk);
1157	list_move(&dc->list, &uncached_devices);
1158
1159	clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1160	clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1161
1162	mutex_unlock(&bch_register_lock);
1163
1164	pr_info("Caching disabled for %s\n", dc->backing_dev_name);
1165
1166	/* Drop ref we took in cached_dev_detach() */
1167	closure_put(&dc->disk.cl);
1168}
1169
1170void bch_cached_dev_detach(struct cached_dev *dc)
1171{
1172	lockdep_assert_held(&bch_register_lock);
1173
1174	if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1175		return;
1176
1177	if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1178		return;
1179
1180	/*
1181	 * Block the device from being closed and freed until we're finished
1182	 * detaching
1183	 */
1184	closure_get(&dc->disk.cl);
1185
1186	bch_writeback_queue(dc);
1187
1188	cached_dev_put(dc);
1189}
1190
1191int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1192			  uint8_t *set_uuid)
1193{
1194	uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1195	struct uuid_entry *u;
1196	struct cached_dev *exist_dc, *t;
1197	int ret = 0;
1198
1199	if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
1200	    (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
1201		return -ENOENT;
1202
1203	if (dc->disk.c) {
1204		pr_err("Can't attach %s: already attached\n",
1205		       dc->backing_dev_name);
1206		return -EINVAL;
1207	}
1208
1209	if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1210		pr_err("Can't attach %s: shutting down\n",
1211		       dc->backing_dev_name);
1212		return -EINVAL;
1213	}
1214
1215	if (dc->sb.block_size < c->sb.block_size) {
1216		/* Will die */
1217		pr_err("Couldn't attach %s: block size less than set's block size\n",
1218		       dc->backing_dev_name);
1219		return -EINVAL;
1220	}
1221
1222	/* Check whether already attached */
1223	list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1224		if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1225			pr_err("Tried to attach %s but duplicate UUID already attached\n",
1226				dc->backing_dev_name);
1227
1228			return -EINVAL;
1229		}
1230	}
1231
1232	u = uuid_find(c, dc->sb.uuid);
1233
1234	if (u &&
1235	    (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1236	     BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1237		memcpy(u->uuid, invalid_uuid, 16);
1238		u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1239		u = NULL;
1240	}
1241
1242	if (!u) {
1243		if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1244			pr_err("Couldn't find uuid for %s in set\n",
1245			       dc->backing_dev_name);
1246			return -ENOENT;
1247		}
1248
1249		u = uuid_find_empty(c);
1250		if (!u) {
1251			pr_err("Not caching %s, no room for UUID\n",
1252			       dc->backing_dev_name);
1253			return -EINVAL;
1254		}
1255	}
1256
1257	/*
1258	 * Deadlocks since we're called via sysfs...
1259	 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1260	 */
1261
1262	if (bch_is_zero(u->uuid, 16)) {
1263		struct closure cl;
1264
1265		closure_init_stack(&cl);
1266
1267		memcpy(u->uuid, dc->sb.uuid, 16);
1268		memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1269		u->first_reg = u->last_reg = rtime;
1270		bch_uuid_write(c);
1271
1272		memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
1273		SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1274
1275		bch_write_bdev_super(dc, &cl);
1276		closure_sync(&cl);
1277	} else {
1278		u->last_reg = rtime;
1279		bch_uuid_write(c);
1280	}
1281
1282	bcache_device_attach(&dc->disk, c, u - c->uuids);
1283	list_move(&dc->list, &c->cached_devs);
1284	calc_cached_dev_sectors(c);
1285
1286	/*
1287	 * dc->c must be set before dc->count != 0 - paired with the mb in
1288	 * cached_dev_get()
1289	 */
1290	smp_wmb();
1291	refcount_set(&dc->count, 1);
1292
1293	/* Block writeback thread, but spawn it */
1294	down_write(&dc->writeback_lock);
1295	if (bch_cached_dev_writeback_start(dc)) {
1296		up_write(&dc->writeback_lock);
1297		pr_err("Couldn't start writeback facilities for %s\n",
1298		       dc->disk.disk->disk_name);
1299		return -ENOMEM;
1300	}
1301
1302	if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1303		atomic_set(&dc->has_dirty, 1);
1304		bch_writeback_queue(dc);
1305	}
1306
1307	bch_sectors_dirty_init(&dc->disk);
1308
1309	ret = bch_cached_dev_run(dc);
1310	if (ret && (ret != -EBUSY)) {
1311		up_write(&dc->writeback_lock);
1312		/*
1313		 * bch_register_lock is held, bcache_device_stop() is not
1314		 * able to be directly called. The kthread and kworker
1315		 * created previously in bch_cached_dev_writeback_start()
1316		 * have to be stopped manually here.
1317		 */
1318		kthread_stop(dc->writeback_thread);
1319		cancel_writeback_rate_update_dwork(dc);
1320		pr_err("Couldn't run cached device %s\n",
1321		       dc->backing_dev_name);
1322		return ret;
1323	}
1324
1325	bcache_device_link(&dc->disk, c, "bdev");
1326	atomic_inc(&c->attached_dev_nr);
1327
1328	/* Allow the writeback thread to proceed */
1329	up_write(&dc->writeback_lock);
1330
1331	pr_info("Caching %s as %s on set %pU\n",
1332		dc->backing_dev_name,
1333		dc->disk.disk->disk_name,
1334		dc->disk.c->sb.set_uuid);
1335	return 0;
1336}
1337
1338/* when dc->disk.kobj released */
1339void bch_cached_dev_release(struct kobject *kobj)
1340{
1341	struct cached_dev *dc = container_of(kobj, struct cached_dev,
1342					     disk.kobj);
1343	kfree(dc);
1344	module_put(THIS_MODULE);
1345}
1346
1347static void cached_dev_free(struct closure *cl)
1348{
1349	struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1350
1351	if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1352		cancel_writeback_rate_update_dwork(dc);
1353
1354	if (!IS_ERR_OR_NULL(dc->writeback_thread))
1355		kthread_stop(dc->writeback_thread);
1356	if (!IS_ERR_OR_NULL(dc->status_update_thread))
1357		kthread_stop(dc->status_update_thread);
1358
1359	mutex_lock(&bch_register_lock);
1360
1361	if (atomic_read(&dc->running))
1362		bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1363	bcache_device_free(&dc->disk);
1364	list_del(&dc->list);
1365
1366	mutex_unlock(&bch_register_lock);
1367
1368	if (dc->sb_disk)
1369		put_page(virt_to_page(dc->sb_disk));
1370
1371	if (!IS_ERR_OR_NULL(dc->bdev))
1372		blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1373
1374	wake_up(&unregister_wait);
1375
1376	kobject_put(&dc->disk.kobj);
1377}
1378
1379static void cached_dev_flush(struct closure *cl)
1380{
1381	struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1382	struct bcache_device *d = &dc->disk;
1383
1384	mutex_lock(&bch_register_lock);
1385	bcache_device_unlink(d);
1386	mutex_unlock(&bch_register_lock);
1387
1388	bch_cache_accounting_destroy(&dc->accounting);
1389	kobject_del(&d->kobj);
1390
1391	continue_at(cl, cached_dev_free, system_wq);
1392}
1393
1394static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1395{
1396	int ret;
1397	struct io *io;
1398	struct request_queue *q = bdev_get_queue(dc->bdev);
1399
1400	__module_get(THIS_MODULE);
1401	INIT_LIST_HEAD(&dc->list);
1402	closure_init(&dc->disk.cl, NULL);
1403	set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1404	kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1405	INIT_WORK(&dc->detach, cached_dev_detach_finish);
1406	sema_init(&dc->sb_write_mutex, 1);
1407	INIT_LIST_HEAD(&dc->io_lru);
1408	spin_lock_init(&dc->io_lock);
1409	bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1410
1411	dc->sequential_cutoff		= 4 << 20;
1412
1413	for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1414		list_add(&io->lru, &dc->io_lru);
1415		hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1416	}
1417
1418	dc->disk.stripe_size = q->limits.io_opt >> 9;
1419
1420	if (dc->disk.stripe_size)
1421		dc->partial_stripes_expensive =
1422			q->limits.raid_partial_stripes_expensive;
1423
1424	ret = bcache_device_init(&dc->disk, block_size,
1425			 dc->bdev->bd_part->nr_sects - dc->sb.data_offset,
1426			 dc->bdev, &bcache_cached_ops);
1427	if (ret)
1428		return ret;
1429
1430	dc->disk.disk->queue->backing_dev_info->ra_pages =
1431		max(dc->disk.disk->queue->backing_dev_info->ra_pages,
1432		    q->backing_dev_info->ra_pages);
1433
1434	atomic_set(&dc->io_errors, 0);
1435	dc->io_disable = false;
1436	dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1437	/* default to auto */
1438	dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1439
1440	bch_cached_dev_request_init(dc);
1441	bch_cached_dev_writeback_init(dc);
1442	return 0;
1443}
1444
1445/* Cached device - bcache superblock */
1446
1447static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1448				 struct block_device *bdev,
1449				 struct cached_dev *dc)
1450{
1451	const char *err = "cannot allocate memory";
1452	struct cache_set *c;
1453	int ret = -ENOMEM;
1454
1455	bdevname(bdev, dc->backing_dev_name);
1456	memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1457	dc->bdev = bdev;
1458	dc->bdev->bd_holder = dc;
1459	dc->sb_disk = sb_disk;
1460
1461	if (cached_dev_init(dc, sb->block_size << 9))
1462		goto err;
1463
1464	err = "error creating kobject";
1465	if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1466			"bcache"))
1467		goto err;
1468	if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1469		goto err;
1470
1471	pr_info("registered backing device %s\n", dc->backing_dev_name);
1472
1473	list_add(&dc->list, &uncached_devices);
1474	/* attach to a matched cache set if it exists */
1475	list_for_each_entry(c, &bch_cache_sets, list)
1476		bch_cached_dev_attach(dc, c, NULL);
1477
1478	if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1479	    BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1480		err = "failed to run cached device";
1481		ret = bch_cached_dev_run(dc);
1482		if (ret)
1483			goto err;
1484	}
1485
1486	return 0;
1487err:
1488	pr_notice("error %s: %s\n", dc->backing_dev_name, err);
1489	bcache_device_stop(&dc->disk);
1490	return ret;
1491}
1492
1493/* Flash only volumes */
1494
1495/* When d->kobj released */
1496void bch_flash_dev_release(struct kobject *kobj)
1497{
1498	struct bcache_device *d = container_of(kobj, struct bcache_device,
1499					       kobj);
1500	kfree(d);
1501}
1502
1503static void flash_dev_free(struct closure *cl)
1504{
1505	struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1506
1507	mutex_lock(&bch_register_lock);
1508	atomic_long_sub(bcache_dev_sectors_dirty(d),
1509			&d->c->flash_dev_dirty_sectors);
1510	bcache_device_free(d);
1511	mutex_unlock(&bch_register_lock);
1512	kobject_put(&d->kobj);
1513}
1514
1515static void flash_dev_flush(struct closure *cl)
1516{
1517	struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1518
1519	mutex_lock(&bch_register_lock);
1520	bcache_device_unlink(d);
1521	mutex_unlock(&bch_register_lock);
1522	kobject_del(&d->kobj);
1523	continue_at(cl, flash_dev_free, system_wq);
1524}
1525
1526static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1527{
1528	struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1529					  GFP_KERNEL);
1530	if (!d)
1531		return -ENOMEM;
1532
1533	closure_init(&d->cl, NULL);
1534	set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1535
1536	kobject_init(&d->kobj, &bch_flash_dev_ktype);
1537
1538	if (bcache_device_init(d, block_bytes(c), u->sectors,
1539			NULL, &bcache_flash_ops))
1540		goto err;
1541
1542	bcache_device_attach(d, c, u - c->uuids);
1543	bch_sectors_dirty_init(d);
1544	bch_flash_dev_request_init(d);
1545	add_disk(d->disk);
1546
1547	if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1548		goto err;
1549
1550	bcache_device_link(d, c, "volume");
1551
1552	return 0;
1553err:
1554	kobject_put(&d->kobj);
1555	return -ENOMEM;
1556}
1557
1558static int flash_devs_run(struct cache_set *c)
1559{
1560	int ret = 0;
1561	struct uuid_entry *u;
1562
1563	for (u = c->uuids;
1564	     u < c->uuids + c->nr_uuids && !ret;
1565	     u++)
1566		if (UUID_FLASH_ONLY(u))
1567			ret = flash_dev_run(c, u);
1568
1569	return ret;
1570}
1571
1572int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1573{
1574	struct uuid_entry *u;
1575
1576	if (test_bit(CACHE_SET_STOPPING, &c->flags))
1577		return -EINTR;
1578
1579	if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1580		return -EPERM;
1581
1582	u = uuid_find_empty(c);
1583	if (!u) {
1584		pr_err("Can't create volume, no room for UUID\n");
1585		return -EINVAL;
1586	}
1587
1588	get_random_bytes(u->uuid, 16);
1589	memset(u->label, 0, 32);
1590	u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1591
1592	SET_UUID_FLASH_ONLY(u, 1);
1593	u->sectors = size >> 9;
1594
1595	bch_uuid_write(c);
1596
1597	return flash_dev_run(c, u);
1598}
1599
1600bool bch_cached_dev_error(struct cached_dev *dc)
1601{
1602	if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1603		return false;
1604
1605	dc->io_disable = true;
1606	/* make others know io_disable is true earlier */
1607	smp_mb();
1608
1609	pr_err("stop %s: too many IO errors on backing device %s\n",
1610	       dc->disk.disk->disk_name, dc->backing_dev_name);
1611
1612	bcache_device_stop(&dc->disk);
1613	return true;
1614}
1615
1616/* Cache set */
1617
1618__printf(2, 3)
1619bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1620{
1621	struct va_format vaf;
1622	va_list args;
1623
1624	if (c->on_error != ON_ERROR_PANIC &&
1625	    test_bit(CACHE_SET_STOPPING, &c->flags))
1626		return false;
1627
1628	if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1629		pr_info("CACHE_SET_IO_DISABLE already set\n");
1630
1631	/*
1632	 * XXX: we can be called from atomic context
1633	 * acquire_console_sem();
1634	 */
1635
1636	va_start(args, fmt);
1637
1638	vaf.fmt = fmt;
1639	vaf.va = &args;
1640
1641	pr_err("error on %pU: %pV, disabling caching\n",
1642	       c->sb.set_uuid, &vaf);
1643
1644	va_end(args);
1645
1646	if (c->on_error == ON_ERROR_PANIC)
1647		panic("panic forced after error\n");
1648
1649	bch_cache_set_unregister(c);
1650	return true;
1651}
1652
1653/* When c->kobj released */
1654void bch_cache_set_release(struct kobject *kobj)
1655{
1656	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1657
1658	kfree(c);
1659	module_put(THIS_MODULE);
1660}
1661
1662static void cache_set_free(struct closure *cl)
1663{
1664	struct cache_set *c = container_of(cl, struct cache_set, cl);
1665	struct cache *ca;
1666	unsigned int i;
1667
1668	debugfs_remove(c->debug);
1669
1670	bch_open_buckets_free(c);
1671	bch_btree_cache_free(c);
1672	bch_journal_free(c);
1673
1674	mutex_lock(&bch_register_lock);
1675	for_each_cache(ca, c, i)
1676		if (ca) {
1677			ca->set = NULL;
1678			c->cache[ca->sb.nr_this_dev] = NULL;
1679			kobject_put(&ca->kobj);
1680		}
1681
1682	bch_bset_sort_state_free(&c->sort);
1683	free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->sb)));
1684
1685	if (c->moving_gc_wq)
1686		destroy_workqueue(c->moving_gc_wq);
1687	bioset_exit(&c->bio_split);
1688	mempool_exit(&c->fill_iter);
1689	mempool_exit(&c->bio_meta);
1690	mempool_exit(&c->search);
1691	kfree(c->devices);
1692
1693	list_del(&c->list);
1694	mutex_unlock(&bch_register_lock);
1695
1696	pr_info("Cache set %pU unregistered\n", c->sb.set_uuid);
1697	wake_up(&unregister_wait);
1698
1699	closure_debug_destroy(&c->cl);
1700	kobject_put(&c->kobj);
1701}
1702
1703static void cache_set_flush(struct closure *cl)
1704{
1705	struct cache_set *c = container_of(cl, struct cache_set, caching);
1706	struct cache *ca;
1707	struct btree *b;
1708	unsigned int i;
1709
1710	bch_cache_accounting_destroy(&c->accounting);
1711
1712	kobject_put(&c->internal);
1713	kobject_del(&c->kobj);
1714
1715	if (!IS_ERR_OR_NULL(c->gc_thread))
1716		kthread_stop(c->gc_thread);
1717
1718	if (!IS_ERR_OR_NULL(c->root))
1719		list_add(&c->root->list, &c->btree_cache);
1720
1721	/*
1722	 * Avoid flushing cached nodes if cache set is retiring
1723	 * due to too many I/O errors detected.
1724	 */
1725	if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1726		list_for_each_entry(b, &c->btree_cache, list) {
1727			mutex_lock(&b->write_lock);
1728			if (btree_node_dirty(b))
1729				__bch_btree_node_write(b, NULL);
1730			mutex_unlock(&b->write_lock);
1731		}
1732
1733	for_each_cache(ca, c, i)
1734		if (ca->alloc_thread)
1735			kthread_stop(ca->alloc_thread);
1736
1737	if (c->journal.cur) {
1738		cancel_delayed_work_sync(&c->journal.work);
1739		/* flush last journal entry if needed */
1740		c->journal.work.work.func(&c->journal.work.work);
1741	}
1742
1743	closure_return(cl);
1744}
1745
1746/*
1747 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1748 * cache set is unregistering due to too many I/O errors. In this condition,
1749 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1750 * value and whether the broken cache has dirty data:
1751 *
1752 * dc->stop_when_cache_set_failed    dc->has_dirty   stop bcache device
1753 *  BCH_CACHED_STOP_AUTO               0               NO
1754 *  BCH_CACHED_STOP_AUTO               1               YES
1755 *  BCH_CACHED_DEV_STOP_ALWAYS         0               YES
1756 *  BCH_CACHED_DEV_STOP_ALWAYS         1               YES
1757 *
1758 * The expected behavior is, if stop_when_cache_set_failed is configured to
1759 * "auto" via sysfs interface, the bcache device will not be stopped if the
1760 * backing device is clean on the broken cache device.
1761 */
1762static void conditional_stop_bcache_device(struct cache_set *c,
1763					   struct bcache_device *d,
1764					   struct cached_dev *dc)
1765{
1766	if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1767		pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1768			d->disk->disk_name, c->sb.set_uuid);
1769		bcache_device_stop(d);
1770	} else if (atomic_read(&dc->has_dirty)) {
1771		/*
1772		 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1773		 * and dc->has_dirty == 1
1774		 */
1775		pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1776			d->disk->disk_name);
1777		/*
1778		 * There might be a small time gap that cache set is
1779		 * released but bcache device is not. Inside this time
1780		 * gap, regular I/O requests will directly go into
1781		 * backing device as no cache set attached to. This
1782		 * behavior may also introduce potential inconsistence
1783		 * data in writeback mode while cache is dirty.
1784		 * Therefore before calling bcache_device_stop() due
1785		 * to a broken cache device, dc->io_disable should be
1786		 * explicitly set to true.
1787		 */
1788		dc->io_disable = true;
1789		/* make others know io_disable is true earlier */
1790		smp_mb();
1791		bcache_device_stop(d);
1792	} else {
1793		/*
1794		 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1795		 * and dc->has_dirty == 0
1796		 */
1797		pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1798			d->disk->disk_name);
1799	}
1800}
1801
1802static void __cache_set_unregister(struct closure *cl)
1803{
1804	struct cache_set *c = container_of(cl, struct cache_set, caching);
1805	struct cached_dev *dc;
1806	struct bcache_device *d;
1807	size_t i;
1808
1809	mutex_lock(&bch_register_lock);
1810
1811	for (i = 0; i < c->devices_max_used; i++) {
1812		d = c->devices[i];
1813		if (!d)
1814			continue;
1815
1816		if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1817		    test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1818			dc = container_of(d, struct cached_dev, disk);
1819			bch_cached_dev_detach(dc);
1820			if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1821				conditional_stop_bcache_device(c, d, dc);
1822		} else {
1823			bcache_device_stop(d);
1824		}
1825	}
1826
1827	mutex_unlock(&bch_register_lock);
1828
1829	continue_at(cl, cache_set_flush, system_wq);
1830}
1831
1832void bch_cache_set_stop(struct cache_set *c)
1833{
1834	if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1835		/* closure_fn set to __cache_set_unregister() */
1836		closure_queue(&c->caching);
1837}
1838
1839void bch_cache_set_unregister(struct cache_set *c)
1840{
1841	set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1842	bch_cache_set_stop(c);
1843}
1844
1845#define alloc_bucket_pages(gfp, c)			\
1846	((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(bucket_pages(c))))
1847
1848#define alloc_meta_bucket_pages(gfp, sb)		\
1849	((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1850
1851struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1852{
1853	int iter_size;
1854	struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1855
1856	if (!c)
1857		return NULL;
1858
1859	__module_get(THIS_MODULE);
1860	closure_init(&c->cl, NULL);
1861	set_closure_fn(&c->cl, cache_set_free, system_wq);
1862
1863	closure_init(&c->caching, &c->cl);
1864	set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1865
1866	/* Maybe create continue_at_noreturn() and use it here? */
1867	closure_set_stopped(&c->cl);
1868	closure_put(&c->cl);
1869
1870	kobject_init(&c->kobj, &bch_cache_set_ktype);
1871	kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1872
1873	bch_cache_accounting_init(&c->accounting, &c->cl);
1874
1875	memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1876	c->sb.block_size	= sb->block_size;
1877	c->sb.bucket_size	= sb->bucket_size;
1878	c->sb.nr_in_set		= sb->nr_in_set;
1879	c->sb.last_mount	= sb->last_mount;
1880	c->sb.version		= sb->version;
1881	if (c->sb.version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
1882		c->sb.feature_compat = sb->feature_compat;
1883		c->sb.feature_ro_compat = sb->feature_ro_compat;
1884		c->sb.feature_incompat = sb->feature_incompat;
1885	}
1886
1887	c->bucket_bits		= ilog2(sb->bucket_size);
1888	c->block_bits		= ilog2(sb->block_size);
1889	c->nr_uuids		= meta_bucket_bytes(&c->sb) / sizeof(struct uuid_entry);
1890	c->devices_max_used	= 0;
1891	atomic_set(&c->attached_dev_nr, 0);
1892	c->btree_pages		= meta_bucket_pages(&c->sb);
1893	if (c->btree_pages > BTREE_MAX_PAGES)
1894		c->btree_pages = max_t(int, c->btree_pages / 4,
1895				       BTREE_MAX_PAGES);
1896
1897	sema_init(&c->sb_write_mutex, 1);
1898	mutex_init(&c->bucket_lock);
1899	init_waitqueue_head(&c->btree_cache_wait);
1900	spin_lock_init(&c->btree_cannibalize_lock);
1901	init_waitqueue_head(&c->bucket_wait);
1902	init_waitqueue_head(&c->gc_wait);
1903	sema_init(&c->uuid_write_mutex, 1);
1904
1905	spin_lock_init(&c->btree_gc_time.lock);
1906	spin_lock_init(&c->btree_split_time.lock);
1907	spin_lock_init(&c->btree_read_time.lock);
1908
1909	bch_moving_init_cache_set(c);
1910
1911	INIT_LIST_HEAD(&c->list);
1912	INIT_LIST_HEAD(&c->cached_devs);
1913	INIT_LIST_HEAD(&c->btree_cache);
1914	INIT_LIST_HEAD(&c->btree_cache_freeable);
1915	INIT_LIST_HEAD(&c->btree_cache_freed);
1916	INIT_LIST_HEAD(&c->data_buckets);
1917
1918	iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
1919		sizeof(struct btree_iter_set);
1920
1921	c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1922	if (!c->devices)
1923		goto err;
1924
1925	if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1926		goto err;
1927
1928	if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1929			sizeof(struct bbio) +
1930			sizeof(struct bio_vec) * meta_bucket_pages(&c->sb)))
1931		goto err;
1932
1933	if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1934		goto err;
1935
1936	if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1937			BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
1938		goto err;
1939
1940	c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, &c->sb);
1941	if (!c->uuids)
1942		goto err;
1943
1944	c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
1945	if (!c->moving_gc_wq)
1946		goto err;
1947
1948	if (bch_journal_alloc(c))
1949		goto err;
1950
1951	if (bch_btree_cache_alloc(c))
1952		goto err;
1953
1954	if (bch_open_buckets_alloc(c))
1955		goto err;
1956
1957	if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1958		goto err;
1959
1960	c->congested_read_threshold_us	= 2000;
1961	c->congested_write_threshold_us	= 20000;
1962	c->error_limit	= DEFAULT_IO_ERROR_LIMIT;
1963	c->idle_max_writeback_rate_enabled = 1;
1964	WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1965
1966	return c;
1967err:
1968	bch_cache_set_unregister(c);
1969	return NULL;
1970}
1971
1972static int run_cache_set(struct cache_set *c)
1973{
1974	const char *err = "cannot allocate memory";
1975	struct cached_dev *dc, *t;
1976	struct cache *ca;
1977	struct closure cl;
1978	unsigned int i;
1979	LIST_HEAD(journal);
1980	struct journal_replay *l;
1981
1982	closure_init_stack(&cl);
1983
1984	for_each_cache(ca, c, i)
1985		c->nbuckets += ca->sb.nbuckets;
1986	set_gc_sectors(c);
1987
1988	if (CACHE_SYNC(&c->sb)) {
1989		struct bkey *k;
1990		struct jset *j;
1991
1992		err = "cannot allocate memory for journal";
1993		if (bch_journal_read(c, &journal))
1994			goto err;
1995
1996		pr_debug("btree_journal_read() done\n");
1997
1998		err = "no journal entries found";
1999		if (list_empty(&journal))
2000			goto err;
2001
2002		j = &list_entry(journal.prev, struct journal_replay, list)->j;
2003
2004		err = "IO error reading priorities";
2005		for_each_cache(ca, c, i) {
2006			if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2007				goto err;
2008		}
2009
2010		/*
2011		 * If prio_read() fails it'll call cache_set_error and we'll
2012		 * tear everything down right away, but if we perhaps checked
2013		 * sooner we could avoid journal replay.
2014		 */
2015
2016		k = &j->btree_root;
2017
2018		err = "bad btree root";
2019		if (__bch_btree_ptr_invalid(c, k))
2020			goto err;
2021
2022		err = "error reading btree root";
2023		c->root = bch_btree_node_get(c, NULL, k,
2024					     j->btree_level,
2025					     true, NULL);
2026		if (IS_ERR_OR_NULL(c->root))
2027			goto err;
2028
2029		list_del_init(&c->root->list);
2030		rw_unlock(true, c->root);
2031
2032		err = uuid_read(c, j, &cl);
2033		if (err)
2034			goto err;
2035
2036		err = "error in recovery";
2037		if (bch_btree_check(c))
2038			goto err;
2039
2040		bch_journal_mark(c, &journal);
2041		bch_initial_gc_finish(c);
2042		pr_debug("btree_check() done\n");
2043
2044		/*
2045		 * bcache_journal_next() can't happen sooner, or
2046		 * btree_gc_finish() will give spurious errors about last_gc >
2047		 * gc_gen - this is a hack but oh well.
2048		 */
2049		bch_journal_next(&c->journal);
2050
2051		err = "error starting allocator thread";
2052		for_each_cache(ca, c, i)
2053			if (bch_cache_allocator_start(ca))
2054				goto err;
2055
2056		/*
2057		 * First place it's safe to allocate: btree_check() and
2058		 * btree_gc_finish() have to run before we have buckets to
2059		 * allocate, and bch_bucket_alloc_set() might cause a journal
2060		 * entry to be written so bcache_journal_next() has to be called
2061		 * first.
2062		 *
2063		 * If the uuids were in the old format we have to rewrite them
2064		 * before the next journal entry is written:
2065		 */
2066		if (j->version < BCACHE_JSET_VERSION_UUID)
2067			__uuid_write(c);
2068
2069		err = "bcache: replay journal failed";
2070		if (bch_journal_replay(c, &journal))
2071			goto err;
2072	} else {
2073		pr_notice("invalidating existing data\n");
2074
2075		for_each_cache(ca, c, i) {
2076			unsigned int j;
2077
2078			ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2079					      2, SB_JOURNAL_BUCKETS);
2080
2081			for (j = 0; j < ca->sb.keys; j++)
2082				ca->sb.d[j] = ca->sb.first_bucket + j;
2083		}
2084
2085		bch_initial_gc_finish(c);
2086
2087		err = "error starting allocator thread";
2088		for_each_cache(ca, c, i)
2089			if (bch_cache_allocator_start(ca))
2090				goto err;
2091
2092		mutex_lock(&c->bucket_lock);
2093		for_each_cache(ca, c, i)
2094			bch_prio_write(ca, true);
2095		mutex_unlock(&c->bucket_lock);
2096
2097		err = "cannot allocate new UUID bucket";
2098		if (__uuid_write(c))
2099			goto err;
2100
2101		err = "cannot allocate new btree root";
2102		c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2103		if (IS_ERR_OR_NULL(c->root))
2104			goto err;
2105
2106		mutex_lock(&c->root->write_lock);
2107		bkey_copy_key(&c->root->key, &MAX_KEY);
2108		bch_btree_node_write(c->root, &cl);
2109		mutex_unlock(&c->root->write_lock);
2110
2111		bch_btree_set_root(c->root);
2112		rw_unlock(true, c->root);
2113
2114		/*
2115		 * We don't want to write the first journal entry until
2116		 * everything is set up - fortunately journal entries won't be
2117		 * written until the SET_CACHE_SYNC() here:
2118		 */
2119		SET_CACHE_SYNC(&c->sb, true);
2120
2121		bch_journal_next(&c->journal);
2122		bch_journal_meta(c, &cl);
2123	}
2124
2125	err = "error starting gc thread";
2126	if (bch_gc_thread_start(c))
2127		goto err;
2128
2129	closure_sync(&cl);
2130	c->sb.last_mount = (u32)ktime_get_real_seconds();
2131	bcache_write_super(c);
2132
2133	list_for_each_entry_safe(dc, t, &uncached_devices, list)
2134		bch_cached_dev_attach(dc, c, NULL);
2135
2136	flash_devs_run(c);
2137
2138	set_bit(CACHE_SET_RUNNING, &c->flags);
2139	return 0;
2140err:
2141	while (!list_empty(&journal)) {
2142		l = list_first_entry(&journal, struct journal_replay, list);
2143		list_del(&l->list);
2144		kfree(l);
2145	}
2146
2147	closure_sync(&cl);
2148
2149	bch_cache_set_error(c, "%s", err);
2150
2151	return -EIO;
2152}
2153
2154static bool can_attach_cache(struct cache *ca, struct cache_set *c)
2155{
2156	return ca->sb.block_size	== c->sb.block_size &&
2157		ca->sb.bucket_size	== c->sb.bucket_size &&
2158		ca->sb.nr_in_set	== c->sb.nr_in_set;
2159}
2160
2161static const char *register_cache_set(struct cache *ca)
2162{
2163	char buf[12];
2164	const char *err = "cannot allocate memory";
2165	struct cache_set *c;
2166
2167	list_for_each_entry(c, &bch_cache_sets, list)
2168		if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
2169			if (c->cache[ca->sb.nr_this_dev])
2170				return "duplicate cache set member";
2171
2172			if (!can_attach_cache(ca, c))
2173				return "cache sb does not match set";
2174
2175			if (!CACHE_SYNC(&ca->sb))
2176				SET_CACHE_SYNC(&c->sb, false);
2177
2178			goto found;
2179		}
2180
2181	c = bch_cache_set_alloc(&ca->sb);
2182	if (!c)
2183		return err;
2184
2185	err = "error creating kobject";
2186	if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
2187	    kobject_add(&c->internal, &c->kobj, "internal"))
2188		goto err;
2189
2190	if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2191		goto err;
2192
2193	bch_debug_init_cache_set(c);
2194
2195	list_add(&c->list, &bch_cache_sets);
2196found:
2197	sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2198	if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2199	    sysfs_create_link(&c->kobj, &ca->kobj, buf))
2200		goto err;
2201
2202	/*
2203	 * A special case is both ca->sb.seq and c->sb.seq are 0,
2204	 * such condition happens on a new created cache device whose
2205	 * super block is never flushed yet. In this case c->sb.version
2206	 * and other members should be updated too, otherwise we will
2207	 * have a mistaken super block version in cache set.
2208	 */
2209	if (ca->sb.seq > c->sb.seq || c->sb.seq == 0) {
2210		c->sb.version		= ca->sb.version;
2211		memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2212		c->sb.flags             = ca->sb.flags;
2213		c->sb.seq		= ca->sb.seq;
2214		pr_debug("set version = %llu\n", c->sb.version);
2215	}
2216
2217	kobject_get(&ca->kobj);
2218	ca->set = c;
2219	ca->set->cache[ca->sb.nr_this_dev] = ca;
2220	c->cache_by_alloc[c->caches_loaded++] = ca;
2221
2222	if (c->caches_loaded == c->sb.nr_in_set) {
2223		err = "failed to run cache set";
2224		if (run_cache_set(c) < 0)
2225			goto err;
2226	}
2227
2228	return NULL;
2229err:
2230	bch_cache_set_unregister(c);
2231	return err;
2232}
2233
2234/* Cache device */
2235
2236/* When ca->kobj released */
2237void bch_cache_release(struct kobject *kobj)
2238{
2239	struct cache *ca = container_of(kobj, struct cache, kobj);
2240	unsigned int i;
2241
2242	if (ca->set) {
2243		BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca);
2244		ca->set->cache[ca->sb.nr_this_dev] = NULL;
2245	}
2246
2247	free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2248	kfree(ca->prio_buckets);
2249	vfree(ca->buckets);
2250
2251	free_heap(&ca->heap);
2252	free_fifo(&ca->free_inc);
2253
2254	for (i = 0; i < RESERVE_NR; i++)
2255		free_fifo(&ca->free[i]);
2256
2257	if (ca->sb_disk)
2258		put_page(virt_to_page(ca->sb_disk));
2259
2260	if (!IS_ERR_OR_NULL(ca->bdev))
2261		blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2262
2263	kfree(ca);
2264	module_put(THIS_MODULE);
2265}
2266
2267static int cache_alloc(struct cache *ca)
2268{
2269	size_t free;
2270	size_t btree_buckets;
2271	struct bucket *b;
2272	int ret = -ENOMEM;
2273	const char *err = NULL;
2274
2275	__module_get(THIS_MODULE);
2276	kobject_init(&ca->kobj, &bch_cache_ktype);
2277
2278	bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2279
2280	/*
2281	 * when ca->sb.njournal_buckets is not zero, journal exists,
2282	 * and in bch_journal_replay(), tree node may split,
2283	 * so bucket of RESERVE_BTREE type is needed,
2284	 * the worst situation is all journal buckets are valid journal,
2285	 * and all the keys need to replay,
2286	 * so the number of  RESERVE_BTREE type buckets should be as much
2287	 * as journal buckets
2288	 */
2289	btree_buckets = ca->sb.njournal_buckets ?: 8;
2290	free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2291	if (!free) {
2292		ret = -EPERM;
2293		err = "ca->sb.nbuckets is too small";
2294		goto err_free;
2295	}
2296
2297	if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2298						GFP_KERNEL)) {
2299		err = "ca->free[RESERVE_BTREE] alloc failed";
2300		goto err_btree_alloc;
2301	}
2302
2303	if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2304							GFP_KERNEL)) {
2305		err = "ca->free[RESERVE_PRIO] alloc failed";
2306		goto err_prio_alloc;
2307	}
2308
2309	if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2310		err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2311		goto err_movinggc_alloc;
2312	}
2313
2314	if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2315		err = "ca->free[RESERVE_NONE] alloc failed";
2316		goto err_none_alloc;
2317	}
2318
2319	if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2320		err = "ca->free_inc alloc failed";
2321		goto err_free_inc_alloc;
2322	}
2323
2324	if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2325		err = "ca->heap alloc failed";
2326		goto err_heap_alloc;
2327	}
2328
2329	ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2330			      ca->sb.nbuckets));
2331	if (!ca->buckets) {
2332		err = "ca->buckets alloc failed";
2333		goto err_buckets_alloc;
2334	}
2335
2336	ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2337				   prio_buckets(ca), 2),
2338				   GFP_KERNEL);
2339	if (!ca->prio_buckets) {
2340		err = "ca->prio_buckets alloc failed";
2341		goto err_prio_buckets_alloc;
2342	}
2343
2344	ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2345	if (!ca->disk_buckets) {
2346		err = "ca->disk_buckets alloc failed";
2347		goto err_disk_buckets_alloc;
2348	}
2349
2350	ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2351
2352	for_each_bucket(b, ca)
2353		atomic_set(&b->pin, 0);
2354	return 0;
2355
2356err_disk_buckets_alloc:
2357	kfree(ca->prio_buckets);
2358err_prio_buckets_alloc:
2359	vfree(ca->buckets);
2360err_buckets_alloc:
2361	free_heap(&ca->heap);
2362err_heap_alloc:
2363	free_fifo(&ca->free_inc);
2364err_free_inc_alloc:
2365	free_fifo(&ca->free[RESERVE_NONE]);
2366err_none_alloc:
2367	free_fifo(&ca->free[RESERVE_MOVINGGC]);
2368err_movinggc_alloc:
2369	free_fifo(&ca->free[RESERVE_PRIO]);
2370err_prio_alloc:
2371	free_fifo(&ca->free[RESERVE_BTREE]);
2372err_btree_alloc:
2373err_free:
2374	module_put(THIS_MODULE);
2375	if (err)
2376		pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2377	return ret;
2378}
2379
2380static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2381				struct block_device *bdev, struct cache *ca)
2382{
2383	const char *err = NULL; /* must be set for any error case */
2384	int ret = 0;
2385
2386	bdevname(bdev, ca->cache_dev_name);
2387	memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2388	ca->bdev = bdev;
2389	ca->bdev->bd_holder = ca;
2390	ca->sb_disk = sb_disk;
2391
2392	if (blk_queue_discard(bdev_get_queue(bdev)))
2393		ca->discard = CACHE_DISCARD(&ca->sb);
2394
2395	ret = cache_alloc(ca);
2396	if (ret != 0) {
2397		/*
2398		 * If we failed here, it means ca->kobj is not initialized yet,
2399		 * kobject_put() won't be called and there is no chance to
2400		 * call blkdev_put() to bdev in bch_cache_release(). So we
2401		 * explicitly call blkdev_put() here.
2402		 */
2403		blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2404		if (ret == -ENOMEM)
2405			err = "cache_alloc(): -ENOMEM";
2406		else if (ret == -EPERM)
2407			err = "cache_alloc(): cache device is too small";
2408		else
2409			err = "cache_alloc(): unknown error";
2410		goto err;
2411	}
2412
2413	if (kobject_add(&ca->kobj,
2414			&part_to_dev(bdev->bd_part)->kobj,
2415			"bcache")) {
2416		err = "error calling kobject_add";
2417		ret = -ENOMEM;
2418		goto out;
2419	}
2420
2421	mutex_lock(&bch_register_lock);
2422	err = register_cache_set(ca);
2423	mutex_unlock(&bch_register_lock);
2424
2425	if (err) {
2426		ret = -ENODEV;
2427		goto out;
2428	}
2429
2430	pr_info("registered cache device %s\n", ca->cache_dev_name);
2431
2432out:
2433	kobject_put(&ca->kobj);
2434
2435err:
2436	if (err)
2437		pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2438
2439	return ret;
2440}
2441
2442/* Global interfaces/init */
2443
2444static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2445			       const char *buffer, size_t size);
2446static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2447					 struct kobj_attribute *attr,
2448					 const char *buffer, size_t size);
2449
2450kobj_attribute_write(register,		register_bcache);
2451kobj_attribute_write(register_quiet,	register_bcache);
2452kobj_attribute_write(register_async,	register_bcache);
2453kobj_attribute_write(pendings_cleanup,	bch_pending_bdevs_cleanup);
2454
2455static bool bch_is_open_backing(struct block_device *bdev)
2456{
2457	struct cache_set *c, *tc;
2458	struct cached_dev *dc, *t;
2459
2460	list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2461		list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2462			if (dc->bdev == bdev)
2463				return true;
2464	list_for_each_entry_safe(dc, t, &uncached_devices, list)
2465		if (dc->bdev == bdev)
2466			return true;
2467	return false;
2468}
2469
2470static bool bch_is_open_cache(struct block_device *bdev)
2471{
2472	struct cache_set *c, *tc;
2473	struct cache *ca;
2474	unsigned int i;
2475
2476	list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2477		for_each_cache(ca, c, i)
2478			if (ca->bdev == bdev)
2479				return true;
2480	return false;
2481}
2482
2483static bool bch_is_open(struct block_device *bdev)
2484{
2485	return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
2486}
2487
2488struct async_reg_args {
2489	struct delayed_work reg_work;
2490	char *path;
2491	struct cache_sb *sb;
2492	struct cache_sb_disk *sb_disk;
2493	struct block_device *bdev;
2494};
2495
2496static void register_bdev_worker(struct work_struct *work)
2497{
2498	int fail = false;
2499	struct async_reg_args *args =
2500		container_of(work, struct async_reg_args, reg_work.work);
2501	struct cached_dev *dc;
2502
2503	dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2504	if (!dc) {
2505		fail = true;
2506		put_page(virt_to_page(args->sb_disk));
2507		blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2508		goto out;
2509	}
2510
2511	mutex_lock(&bch_register_lock);
2512	if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
2513		fail = true;
2514	mutex_unlock(&bch_register_lock);
2515
2516out:
2517	if (fail)
2518		pr_info("error %s: fail to register backing device\n",
2519			args->path);
2520	kfree(args->sb);
2521	kfree(args->path);
2522	kfree(args);
2523	module_put(THIS_MODULE);
2524}
2525
2526static void register_cache_worker(struct work_struct *work)
2527{
2528	int fail = false;
2529	struct async_reg_args *args =
2530		container_of(work, struct async_reg_args, reg_work.work);
2531	struct cache *ca;
2532
2533	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2534	if (!ca) {
2535		fail = true;
2536		put_page(virt_to_page(args->sb_disk));
2537		blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2538		goto out;
2539	}
2540
2541	/* blkdev_put() will be called in bch_cache_release() */
2542	if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
2543		fail = true;
2544
2545out:
2546	if (fail)
2547		pr_info("error %s: fail to register cache device\n",
2548			args->path);
2549	kfree(args->sb);
2550	kfree(args->path);
2551	kfree(args);
2552	module_put(THIS_MODULE);
2553}
2554
2555static void register_device_aync(struct async_reg_args *args)
2556{
2557	if (SB_IS_BDEV(args->sb))
2558		INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2559	else
2560		INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2561
2562	/* 10 jiffies is enough for a delay */
2563	queue_delayed_work(system_wq, &args->reg_work, 10);
2564}
2565
2566static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2567			       const char *buffer, size_t size)
2568{
2569	const char *err;
2570	char *path = NULL;
2571	struct cache_sb *sb;
2572	struct cache_sb_disk *sb_disk;
2573	struct block_device *bdev;
2574	ssize_t ret;
2575
2576	ret = -EBUSY;
2577	err = "failed to reference bcache module";
2578	if (!try_module_get(THIS_MODULE))
2579		goto out;
2580
2581	/* For latest state of bcache_is_reboot */
2582	smp_mb();
2583	err = "bcache is in reboot";
2584	if (bcache_is_reboot)
2585		goto out_module_put;
2586
2587	ret = -ENOMEM;
2588	err = "cannot allocate memory";
2589	path = kstrndup(buffer, size, GFP_KERNEL);
2590	if (!path)
2591		goto out_module_put;
2592
2593	sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2594	if (!sb)
2595		goto out_free_path;
2596
2597	ret = -EINVAL;
2598	err = "failed to open device";
2599	bdev = blkdev_get_by_path(strim(path),
2600				  FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2601				  sb);
2602	if (IS_ERR(bdev)) {
2603		if (bdev == ERR_PTR(-EBUSY)) {
2604			bdev = lookup_bdev(strim(path));
2605			mutex_lock(&bch_register_lock);
2606			if (!IS_ERR(bdev) && bch_is_open(bdev))
2607				err = "device already registered";
2608			else
2609				err = "device busy";
2610			mutex_unlock(&bch_register_lock);
2611			if (!IS_ERR(bdev))
2612				bdput(bdev);
2613			if (attr == &ksysfs_register_quiet)
2614				goto done;
2615		}
2616		goto out_free_sb;
2617	}
2618
2619	err = "failed to set blocksize";
2620	if (set_blocksize(bdev, 4096))
2621		goto out_blkdev_put;
2622
2623	err = read_super(sb, bdev, &sb_disk);
2624	if (err)
2625		goto out_blkdev_put;
2626
2627	err = "failed to register device";
2628	if (attr == &ksysfs_register_async) {
2629		/* register in asynchronous way */
2630		struct async_reg_args *args =
2631			kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2632
2633		if (!args) {
2634			ret = -ENOMEM;
2635			err = "cannot allocate memory";
2636			goto out_put_sb_page;
2637		}
2638
2639		args->path	= path;
2640		args->sb	= sb;
2641		args->sb_disk	= sb_disk;
2642		args->bdev	= bdev;
2643		register_device_aync(args);
2644		/* No wait and returns to user space */
2645		goto async_done;
2646	}
2647
2648	if (SB_IS_BDEV(sb)) {
2649		struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2650
2651		if (!dc)
2652			goto out_put_sb_page;
2653
2654		mutex_lock(&bch_register_lock);
2655		ret = register_bdev(sb, sb_disk, bdev, dc);
2656		mutex_unlock(&bch_register_lock);
2657		/* blkdev_put() will be called in cached_dev_free() */
2658		if (ret < 0)
2659			goto out_free_sb;
2660	} else {
2661		struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2662
2663		if (!ca)
2664			goto out_put_sb_page;
2665
2666		/* blkdev_put() will be called in bch_cache_release() */
2667		if (register_cache(sb, sb_disk, bdev, ca) != 0)
2668			goto out_free_sb;
2669	}
2670
2671done:
2672	kfree(sb);
2673	kfree(path);
2674	module_put(THIS_MODULE);
2675async_done:
2676	return size;
2677
2678out_put_sb_page:
2679	put_page(virt_to_page(sb_disk));
2680out_blkdev_put:
2681	blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2682out_free_sb:
2683	kfree(sb);
2684out_free_path:
2685	kfree(path);
2686	path = NULL;
2687out_module_put:
2688	module_put(THIS_MODULE);
2689out:
2690	pr_info("error %s: %s\n", path?path:"", err);
2691	return ret;
2692}
2693
2694
2695struct pdev {
2696	struct list_head list;
2697	struct cached_dev *dc;
2698};
2699
2700static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2701					 struct kobj_attribute *attr,
2702					 const char *buffer,
2703					 size_t size)
2704{
2705	LIST_HEAD(pending_devs);
2706	ssize_t ret = size;
2707	struct cached_dev *dc, *tdc;
2708	struct pdev *pdev, *tpdev;
2709	struct cache_set *c, *tc;
2710
2711	mutex_lock(&bch_register_lock);
2712	list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2713		pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2714		if (!pdev)
2715			break;
2716		pdev->dc = dc;
2717		list_add(&pdev->list, &pending_devs);
2718	}
2719
2720	list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2721		list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2722			char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2723			char *set_uuid = c->sb.uuid;
2724
2725			if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2726				list_del(&pdev->list);
2727				kfree(pdev);
2728				break;
2729			}
2730		}
2731	}
2732	mutex_unlock(&bch_register_lock);
2733
2734	list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2735		pr_info("delete pdev %p\n", pdev);
2736		list_del(&pdev->list);
2737		bcache_device_stop(&pdev->dc->disk);
2738		kfree(pdev);
2739	}
2740
2741	return ret;
2742}
2743
2744static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2745{
2746	if (bcache_is_reboot)
2747		return NOTIFY_DONE;
2748
2749	if (code == SYS_DOWN ||
2750	    code == SYS_HALT ||
2751	    code == SYS_POWER_OFF) {
2752		DEFINE_WAIT(wait);
2753		unsigned long start = jiffies;
2754		bool stopped = false;
2755
2756		struct cache_set *c, *tc;
2757		struct cached_dev *dc, *tdc;
2758
2759		mutex_lock(&bch_register_lock);
2760
2761		if (bcache_is_reboot)
2762			goto out;
2763
2764		/* New registration is rejected since now */
2765		bcache_is_reboot = true;
2766		/*
2767		 * Make registering caller (if there is) on other CPU
2768		 * core know bcache_is_reboot set to true earlier
2769		 */
2770		smp_mb();
2771
2772		if (list_empty(&bch_cache_sets) &&
2773		    list_empty(&uncached_devices))
2774			goto out;
2775
2776		mutex_unlock(&bch_register_lock);
2777
2778		pr_info("Stopping all devices:\n");
2779
2780		/*
2781		 * The reason bch_register_lock is not held to call
2782		 * bch_cache_set_stop() and bcache_device_stop() is to
2783		 * avoid potential deadlock during reboot, because cache
2784		 * set or bcache device stopping process will acqurie
2785		 * bch_register_lock too.
2786		 *
2787		 * We are safe here because bcache_is_reboot sets to
2788		 * true already, register_bcache() will reject new
2789		 * registration now. bcache_is_reboot also makes sure
2790		 * bcache_reboot() won't be re-entered on by other thread,
2791		 * so there is no race in following list iteration by
2792		 * list_for_each_entry_safe().
2793		 */
2794		list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2795			bch_cache_set_stop(c);
2796
2797		list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2798			bcache_device_stop(&dc->disk);
2799
2800
2801		/*
2802		 * Give an early chance for other kthreads and
2803		 * kworkers to stop themselves
2804		 */
2805		schedule();
2806
2807		/* What's a condition variable? */
2808		while (1) {
2809			long timeout = start + 10 * HZ - jiffies;
2810
2811			mutex_lock(&bch_register_lock);
2812			stopped = list_empty(&bch_cache_sets) &&
2813				list_empty(&uncached_devices);
2814
2815			if (timeout < 0 || stopped)
2816				break;
2817
2818			prepare_to_wait(&unregister_wait, &wait,
2819					TASK_UNINTERRUPTIBLE);
2820
2821			mutex_unlock(&bch_register_lock);
2822			schedule_timeout(timeout);
2823		}
2824
2825		finish_wait(&unregister_wait, &wait);
2826
2827		if (stopped)
2828			pr_info("All devices stopped\n");
2829		else
2830			pr_notice("Timeout waiting for devices to be closed\n");
2831out:
2832		mutex_unlock(&bch_register_lock);
2833	}
2834
2835	return NOTIFY_DONE;
2836}
2837
2838static struct notifier_block reboot = {
2839	.notifier_call	= bcache_reboot,
2840	.priority	= INT_MAX, /* before any real devices */
2841};
2842
2843static void bcache_exit(void)
2844{
2845	bch_debug_exit();
2846	bch_request_exit();
2847	if (bcache_kobj)
2848		kobject_put(bcache_kobj);
2849	if (bcache_wq)
2850		destroy_workqueue(bcache_wq);
2851	if (bch_journal_wq)
2852		destroy_workqueue(bch_journal_wq);
2853
2854	if (bcache_major)
2855		unregister_blkdev(bcache_major, "bcache");
2856	unregister_reboot_notifier(&reboot);
2857	mutex_destroy(&bch_register_lock);
2858}
2859
2860/* Check and fixup module parameters */
2861static void check_module_parameters(void)
2862{
2863	if (bch_cutoff_writeback_sync == 0)
2864		bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2865	else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2866		pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2867			bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2868		bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2869	}
2870
2871	if (bch_cutoff_writeback == 0)
2872		bch_cutoff_writeback = CUTOFF_WRITEBACK;
2873	else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2874		pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2875			bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2876		bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2877	}
2878
2879	if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2880		pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2881			bch_cutoff_writeback, bch_cutoff_writeback_sync);
2882		bch_cutoff_writeback = bch_cutoff_writeback_sync;
2883	}
2884}
2885
2886static int __init bcache_init(void)
2887{
2888	static const struct attribute *files[] = {
2889		&ksysfs_register.attr,
2890		&ksysfs_register_quiet.attr,
2891#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2892		&ksysfs_register_async.attr,
2893#endif
2894		&ksysfs_pendings_cleanup.attr,
2895		NULL
2896	};
2897
2898	check_module_parameters();
2899
2900	mutex_init(&bch_register_lock);
2901	init_waitqueue_head(&unregister_wait);
2902	register_reboot_notifier(&reboot);
2903
2904	bcache_major = register_blkdev(0, "bcache");
2905	if (bcache_major < 0) {
2906		unregister_reboot_notifier(&reboot);
2907		mutex_destroy(&bch_register_lock);
2908		return bcache_major;
2909	}
2910
2911	bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2912	if (!bcache_wq)
2913		goto err;
2914
2915	bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2916	if (!bch_journal_wq)
2917		goto err;
2918
2919	bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2920	if (!bcache_kobj)
2921		goto err;
2922
2923	if (bch_request_init() ||
2924	    sysfs_create_files(bcache_kobj, files))
2925		goto err;
2926
2927	bch_debug_init();
2928	closure_debug_init();
2929
2930	bcache_is_reboot = false;
2931
2932	return 0;
2933err:
2934	bcache_exit();
2935	return -ENOMEM;
2936}
2937
2938/*
2939 * Module hooks
2940 */
2941module_exit(bcache_exit);
2942module_init(bcache_init);
2943
2944module_param(bch_cutoff_writeback, uint, 0);
2945MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2946
2947module_param(bch_cutoff_writeback_sync, uint, 0);
2948MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2949
2950MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2951MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2952MODULE_LICENSE("GPL");