2 * bcache setup/teardown code, and some metadata io - read a superblock and
3 * figure out what to do with it.
5 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
6 * Copyright 2012 Google, Inc.
14 #include <linux/buffer_head.h>
15 #include <linux/debugfs.h>
16 #include <linux/genhd.h>
17 #include <linux/module.h>
18 #include <linux/random.h>
19 #include <linux/reboot.h>
20 #include <linux/sysfs.h>
22 MODULE_LICENSE("GPL");
23 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
25 static const char bcache_magic[] = {
26 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
27 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
30 static const char invalid_uuid[] = {
31 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
32 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
35 /* Default is -1; we skip past it for struct cached_dev's cache mode */
36 const char * const bch_cache_modes[] = {
45 struct uuid_entry_v0 {
54 static struct kobject *bcache_kobj;
55 struct mutex bch_register_lock;
56 LIST_HEAD(bch_cache_sets);
57 static LIST_HEAD(uncached_devices);
59 static int bcache_major, bcache_minor;
60 static wait_queue_head_t unregister_wait;
61 struct workqueue_struct *bcache_wq;
63 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
65 static void bio_split_pool_free(struct bio_split_pool *p)
67 if (p->bio_split_hook)
68 mempool_destroy(p->bio_split_hook);
71 bioset_free(p->bio_split);
74 static int bio_split_pool_init(struct bio_split_pool *p)
76 p->bio_split = bioset_create(4, 0);
80 p->bio_split_hook = mempool_create_kmalloc_pool(4,
81 sizeof(struct bio_split_hook));
82 if (!p->bio_split_hook)
90 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
95 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
101 s = (struct cache_sb *) bh->b_data;
103 sb->offset = le64_to_cpu(s->offset);
104 sb->version = le64_to_cpu(s->version);
106 memcpy(sb->magic, s->magic, 16);
107 memcpy(sb->uuid, s->uuid, 16);
108 memcpy(sb->set_uuid, s->set_uuid, 16);
109 memcpy(sb->label, s->label, SB_LABEL_SIZE);
111 sb->flags = le64_to_cpu(s->flags);
112 sb->seq = le64_to_cpu(s->seq);
113 sb->last_mount = le32_to_cpu(s->last_mount);
114 sb->first_bucket = le16_to_cpu(s->first_bucket);
115 sb->keys = le16_to_cpu(s->keys);
117 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
118 sb->d[i] = le64_to_cpu(s->d[i]);
120 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
121 sb->version, sb->flags, sb->seq, sb->keys);
123 err = "Not a bcache superblock";
124 if (sb->offset != SB_SECTOR)
127 if (memcmp(sb->magic, bcache_magic, 16))
130 err = "Too many journal buckets";
131 if (sb->keys > SB_JOURNAL_BUCKETS)
134 err = "Bad checksum";
135 if (s->csum != csum_set(s))
139 if (bch_is_zero(sb->uuid, 16))
142 sb->block_size = le16_to_cpu(s->block_size);
144 err = "Superblock block size smaller than device block size";
145 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
148 switch (sb->version) {
149 case BCACHE_SB_VERSION_BDEV:
150 sb->data_offset = BDEV_DATA_START_DEFAULT;
152 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
153 sb->data_offset = le64_to_cpu(s->data_offset);
155 err = "Bad data offset";
156 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
160 case BCACHE_SB_VERSION_CDEV:
161 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
162 sb->nbuckets = le64_to_cpu(s->nbuckets);
163 sb->block_size = le16_to_cpu(s->block_size);
164 sb->bucket_size = le16_to_cpu(s->bucket_size);
166 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
167 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
169 err = "Too many buckets";
170 if (sb->nbuckets > LONG_MAX)
173 err = "Not enough buckets";
174 if (sb->nbuckets < 1 << 7)
177 err = "Bad block/bucket size";
178 if (!is_power_of_2(sb->block_size) ||
179 sb->block_size > PAGE_SECTORS ||
180 !is_power_of_2(sb->bucket_size) ||
181 sb->bucket_size < PAGE_SECTORS)
184 err = "Invalid superblock: device too small";
185 if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets)
189 if (bch_is_zero(sb->set_uuid, 16))
192 err = "Bad cache device number in set";
193 if (!sb->nr_in_set ||
194 sb->nr_in_set <= sb->nr_this_dev ||
195 sb->nr_in_set > MAX_CACHES_PER_SET)
198 err = "Journal buckets not sequential";
199 for (i = 0; i < sb->keys; i++)
200 if (sb->d[i] != sb->first_bucket + i)
203 err = "Too many journal buckets";
204 if (sb->first_bucket + sb->keys > sb->nbuckets)
207 err = "Invalid superblock: first bucket comes before end of super";
208 if (sb->first_bucket * sb->bucket_size < 16)
213 err = "Unsupported superblock version";
217 sb->last_mount = get_seconds();
220 get_page(bh->b_page);
227 static void write_bdev_super_endio(struct bio *bio, int error)
229 struct cached_dev *dc = bio->bi_private;
230 /* XXX: error checking */
232 closure_put(&dc->sb_write.cl);
235 static void __write_super(struct cache_sb *sb, struct bio *bio)
237 struct cache_sb *out = page_address(bio->bi_io_vec[0].bv_page);
240 bio->bi_sector = SB_SECTOR;
241 bio->bi_rw = REQ_SYNC|REQ_META;
242 bio->bi_size = SB_SIZE;
243 bch_bio_map(bio, NULL);
245 out->offset = cpu_to_le64(sb->offset);
246 out->version = cpu_to_le64(sb->version);
248 memcpy(out->uuid, sb->uuid, 16);
249 memcpy(out->set_uuid, sb->set_uuid, 16);
250 memcpy(out->label, sb->label, SB_LABEL_SIZE);
252 out->flags = cpu_to_le64(sb->flags);
253 out->seq = cpu_to_le64(sb->seq);
255 out->last_mount = cpu_to_le32(sb->last_mount);
256 out->first_bucket = cpu_to_le16(sb->first_bucket);
257 out->keys = cpu_to_le16(sb->keys);
259 for (i = 0; i < sb->keys; i++)
260 out->d[i] = cpu_to_le64(sb->d[i]);
262 out->csum = csum_set(out);
264 pr_debug("ver %llu, flags %llu, seq %llu",
265 sb->version, sb->flags, sb->seq);
267 submit_bio(REQ_WRITE, bio);
270 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
272 struct closure *cl = &dc->sb_write.cl;
273 struct bio *bio = &dc->sb_bio;
275 closure_lock(&dc->sb_write, parent);
278 bio->bi_bdev = dc->bdev;
279 bio->bi_end_io = write_bdev_super_endio;
280 bio->bi_private = dc;
283 __write_super(&dc->sb, bio);
288 static void write_super_endio(struct bio *bio, int error)
290 struct cache *ca = bio->bi_private;
292 bch_count_io_errors(ca, error, "writing superblock");
293 closure_put(&ca->set->sb_write.cl);
296 void bcache_write_super(struct cache_set *c)
298 struct closure *cl = &c->sb_write.cl;
302 closure_lock(&c->sb_write, &c->cl);
306 for_each_cache(ca, c, i) {
307 struct bio *bio = &ca->sb_bio;
309 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
310 ca->sb.seq = c->sb.seq;
311 ca->sb.last_mount = c->sb.last_mount;
313 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
316 bio->bi_bdev = ca->bdev;
317 bio->bi_end_io = write_super_endio;
318 bio->bi_private = ca;
321 __write_super(&ca->sb, bio);
329 static void uuid_endio(struct bio *bio, int error)
331 struct closure *cl = bio->bi_private;
332 struct cache_set *c = container_of(cl, struct cache_set, uuid_write.cl);
334 cache_set_err_on(error, c, "accessing uuids");
335 bch_bbio_free(bio, c);
339 static void uuid_io(struct cache_set *c, unsigned long rw,
340 struct bkey *k, struct closure *parent)
342 struct closure *cl = &c->uuid_write.cl;
343 struct uuid_entry *u;
347 closure_lock(&c->uuid_write, parent);
349 for (i = 0; i < KEY_PTRS(k); i++) {
350 struct bio *bio = bch_bbio_alloc(c);
352 bio->bi_rw = REQ_SYNC|REQ_META|rw;
353 bio->bi_size = KEY_SIZE(k) << 9;
355 bio->bi_end_io = uuid_endio;
356 bio->bi_private = cl;
357 bch_bio_map(bio, c->uuids);
359 bch_submit_bbio(bio, c, k, i);
365 pr_debug("%s UUIDs at %s", rw & REQ_WRITE ? "wrote" : "read",
366 pkey(&c->uuid_bucket));
368 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
369 if (!bch_is_zero(u->uuid, 16))
370 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
371 u - c->uuids, u->uuid, u->label,
372 u->first_reg, u->last_reg, u->invalidated);
377 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
379 struct bkey *k = &j->uuid_bucket;
381 if (__bch_ptr_invalid(c, 1, k))
382 return "bad uuid pointer";
384 bkey_copy(&c->uuid_bucket, k);
385 uuid_io(c, READ_SYNC, k, cl);
387 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
388 struct uuid_entry_v0 *u0 = (void *) c->uuids;
389 struct uuid_entry *u1 = (void *) c->uuids;
395 * Since the new uuid entry is bigger than the old, we have to
396 * convert starting at the highest memory address and work down
397 * in order to do it in place
400 for (i = c->nr_uuids - 1;
403 memcpy(u1[i].uuid, u0[i].uuid, 16);
404 memcpy(u1[i].label, u0[i].label, 32);
406 u1[i].first_reg = u0[i].first_reg;
407 u1[i].last_reg = u0[i].last_reg;
408 u1[i].invalidated = u0[i].invalidated;
418 static int __uuid_write(struct cache_set *c)
422 closure_init_stack(&cl);
424 lockdep_assert_held(&bch_register_lock);
426 if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, &cl))
429 SET_KEY_SIZE(&k.key, c->sb.bucket_size);
430 uuid_io(c, REQ_WRITE, &k.key, &cl);
433 bkey_copy(&c->uuid_bucket, &k.key);
434 __bkey_put(c, &k.key);
438 int bch_uuid_write(struct cache_set *c)
440 int ret = __uuid_write(c);
443 bch_journal_meta(c, NULL);
448 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
450 struct uuid_entry *u;
453 u < c->uuids + c->nr_uuids; u++)
454 if (!memcmp(u->uuid, uuid, 16))
460 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
462 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
463 return uuid_find(c, zero_uuid);
467 * Bucket priorities/gens:
469 * For each bucket, we store on disk its
473 * See alloc.c for an explanation of the gen. The priority is used to implement
474 * lru (and in the future other) cache replacement policies; for most purposes
475 * it's just an opaque integer.
477 * The gens and the priorities don't have a whole lot to do with each other, and
478 * it's actually the gens that must be written out at specific times - it's no
479 * big deal if the priorities don't get written, if we lose them we just reuse
480 * buckets in suboptimal order.
482 * On disk they're stored in a packed array, and in as many buckets are required
483 * to fit them all. The buckets we use to store them form a list; the journal
484 * header points to the first bucket, the first bucket points to the second
487 * This code is used by the allocation code; periodically (whenever it runs out
488 * of buckets to allocate from) the allocation code will invalidate some
489 * buckets, but it can't use those buckets until their new gens are safely on
493 static void prio_endio(struct bio *bio, int error)
495 struct cache *ca = bio->bi_private;
497 cache_set_err_on(error, ca->set, "accessing priorities");
498 bch_bbio_free(bio, ca->set);
499 closure_put(&ca->prio);
502 static void prio_io(struct cache *ca, uint64_t bucket, unsigned long rw)
504 struct closure *cl = &ca->prio;
505 struct bio *bio = bch_bbio_alloc(ca->set);
507 closure_init_stack(cl);
509 bio->bi_sector = bucket * ca->sb.bucket_size;
510 bio->bi_bdev = ca->bdev;
511 bio->bi_rw = REQ_SYNC|REQ_META|rw;
512 bio->bi_size = bucket_bytes(ca);
514 bio->bi_end_io = prio_endio;
515 bio->bi_private = ca;
516 bch_bio_map(bio, ca->disk_buckets);
518 closure_bio_submit(bio, &ca->prio, ca);
522 #define buckets_free(c) "free %zu, free_inc %zu, unused %zu", \
523 fifo_used(&c->free), fifo_used(&c->free_inc), fifo_used(&c->unused)
525 void bch_prio_write(struct cache *ca)
531 closure_init_stack(&cl);
533 lockdep_assert_held(&ca->set->bucket_lock);
535 for (b = ca->buckets;
536 b < ca->buckets + ca->sb.nbuckets; b++)
537 b->disk_gen = b->gen;
539 ca->disk_buckets->seq++;
541 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
542 &ca->meta_sectors_written);
544 pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free),
545 fifo_used(&ca->free_inc), fifo_used(&ca->unused));
546 blktrace_msg(ca, "Starting priorities: " buckets_free(ca));
548 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
550 struct prio_set *p = ca->disk_buckets;
551 struct bucket_disk *d = p->data;
552 struct bucket_disk *end = d + prios_per_bucket(ca);
554 for (b = ca->buckets + i * prios_per_bucket(ca);
555 b < ca->buckets + ca->sb.nbuckets && d < end;
557 d->prio = cpu_to_le16(b->prio);
561 p->next_bucket = ca->prio_buckets[i + 1];
562 p->magic = pset_magic(ca);
563 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
565 bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, &cl);
566 BUG_ON(bucket == -1);
568 mutex_unlock(&ca->set->bucket_lock);
569 prio_io(ca, bucket, REQ_WRITE);
570 mutex_lock(&ca->set->bucket_lock);
572 ca->prio_buckets[i] = bucket;
573 atomic_dec_bug(&ca->buckets[bucket].pin);
576 mutex_unlock(&ca->set->bucket_lock);
578 bch_journal_meta(ca->set, &cl);
581 mutex_lock(&ca->set->bucket_lock);
583 ca->need_save_prio = 0;
586 * Don't want the old priorities to get garbage collected until after we
587 * finish writing the new ones, and they're journalled
589 for (i = 0; i < prio_buckets(ca); i++)
590 ca->prio_last_buckets[i] = ca->prio_buckets[i];
593 static void prio_read(struct cache *ca, uint64_t bucket)
595 struct prio_set *p = ca->disk_buckets;
596 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
598 unsigned bucket_nr = 0;
600 for (b = ca->buckets;
601 b < ca->buckets + ca->sb.nbuckets;
604 ca->prio_buckets[bucket_nr] = bucket;
605 ca->prio_last_buckets[bucket_nr] = bucket;
608 prio_io(ca, bucket, READ_SYNC);
610 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8))
611 pr_warn("bad csum reading priorities");
613 if (p->magic != pset_magic(ca))
614 pr_warn("bad magic reading priorities");
616 bucket = p->next_bucket;
620 b->prio = le16_to_cpu(d->prio);
621 b->gen = b->disk_gen = b->last_gc = b->gc_gen = d->gen;
627 static int open_dev(struct block_device *b, fmode_t mode)
629 struct bcache_device *d = b->bd_disk->private_data;
630 if (atomic_read(&d->closing))
637 static void release_dev(struct gendisk *b, fmode_t mode)
639 struct bcache_device *d = b->private_data;
643 static int ioctl_dev(struct block_device *b, fmode_t mode,
644 unsigned int cmd, unsigned long arg)
646 struct bcache_device *d = b->bd_disk->private_data;
647 return d->ioctl(d, mode, cmd, arg);
650 static const struct block_device_operations bcache_ops = {
652 .release = release_dev,
654 .owner = THIS_MODULE,
657 void bcache_device_stop(struct bcache_device *d)
659 if (!atomic_xchg(&d->closing, 1))
660 closure_queue(&d->cl);
663 static void bcache_device_unlink(struct bcache_device *d)
668 sysfs_remove_link(&d->c->kobj, d->name);
669 sysfs_remove_link(&d->kobj, "cache");
671 for_each_cache(ca, d->c, i)
672 bd_unlink_disk_holder(ca->bdev, d->disk);
675 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
681 for_each_cache(ca, d->c, i)
682 bd_link_disk_holder(ca->bdev, d->disk);
684 snprintf(d->name, BCACHEDEVNAME_SIZE,
685 "%s%u", name, d->id);
687 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
688 sysfs_create_link(&c->kobj, &d->kobj, d->name),
689 "Couldn't create device <-> cache set symlinks");
692 static void bcache_device_detach(struct bcache_device *d)
694 lockdep_assert_held(&bch_register_lock);
696 if (atomic_read(&d->detaching)) {
697 struct uuid_entry *u = d->c->uuids + d->id;
699 SET_UUID_FLASH_ONLY(u, 0);
700 memcpy(u->uuid, invalid_uuid, 16);
701 u->invalidated = cpu_to_le32(get_seconds());
702 bch_uuid_write(d->c);
704 atomic_set(&d->detaching, 0);
707 bcache_device_unlink(d);
709 d->c->devices[d->id] = NULL;
710 closure_put(&d->c->caching);
714 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
717 BUG_ON(test_bit(CACHE_SET_STOPPING, &c->flags));
723 closure_get(&c->caching);
726 static void bcache_device_free(struct bcache_device *d)
728 lockdep_assert_held(&bch_register_lock);
730 pr_info("%s stopped", d->disk->disk_name);
733 bcache_device_detach(d);
734 if (d->disk && d->disk->flags & GENHD_FL_UP)
735 del_gendisk(d->disk);
736 if (d->disk && d->disk->queue)
737 blk_cleanup_queue(d->disk->queue);
741 bio_split_pool_free(&d->bio_split_hook);
742 if (d->unaligned_bvec)
743 mempool_destroy(d->unaligned_bvec);
745 bioset_free(d->bio_split);
747 closure_debug_destroy(&d->cl);
750 static int bcache_device_init(struct bcache_device *d, unsigned block_size)
752 struct request_queue *q;
754 if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
755 !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
756 sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
757 bio_split_pool_init(&d->bio_split_hook) ||
758 !(d->disk = alloc_disk(1)) ||
759 !(q = blk_alloc_queue(GFP_KERNEL)))
762 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor);
764 d->disk->major = bcache_major;
765 d->disk->first_minor = bcache_minor++;
766 d->disk->fops = &bcache_ops;
767 d->disk->private_data = d;
769 blk_queue_make_request(q, NULL);
772 q->backing_dev_info.congested_data = d;
773 q->limits.max_hw_sectors = UINT_MAX;
774 q->limits.max_sectors = UINT_MAX;
775 q->limits.max_segment_size = UINT_MAX;
776 q->limits.max_segments = BIO_MAX_PAGES;
777 q->limits.max_discard_sectors = UINT_MAX;
778 q->limits.io_min = block_size;
779 q->limits.logical_block_size = block_size;
780 q->limits.physical_block_size = block_size;
781 set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags);
782 set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags);
789 static void calc_cached_dev_sectors(struct cache_set *c)
791 uint64_t sectors = 0;
792 struct cached_dev *dc;
794 list_for_each_entry(dc, &c->cached_devs, list)
795 sectors += bdev_sectors(dc->bdev);
797 c->cached_dev_sectors = sectors;
800 void bch_cached_dev_run(struct cached_dev *dc)
802 struct bcache_device *d = &dc->disk;
804 if (atomic_xchg(&dc->running, 1))
808 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
810 closure_init_stack(&cl);
812 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
813 bch_write_bdev_super(dc, &cl);
818 bd_link_disk_holder(dc->bdev, dc->disk.disk);
820 char *env[] = { "SYMLINK=label" , NULL };
821 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
823 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
824 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
825 pr_debug("error creating sysfs link");
828 static void cached_dev_detach_finish(struct work_struct *w)
830 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
831 char buf[BDEVNAME_SIZE];
833 closure_init_stack(&cl);
835 BUG_ON(!atomic_read(&dc->disk.detaching));
836 BUG_ON(atomic_read(&dc->count));
838 mutex_lock(&bch_register_lock);
840 memset(&dc->sb.set_uuid, 0, 16);
841 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
843 bch_write_bdev_super(dc, &cl);
846 bcache_device_detach(&dc->disk);
847 list_move(&dc->list, &uncached_devices);
849 mutex_unlock(&bch_register_lock);
851 pr_info("Caching disabled for %s", bdevname(dc->bdev, buf));
853 /* Drop ref we took in cached_dev_detach() */
854 closure_put(&dc->disk.cl);
857 void bch_cached_dev_detach(struct cached_dev *dc)
859 lockdep_assert_held(&bch_register_lock);
861 if (atomic_read(&dc->disk.closing))
864 if (atomic_xchg(&dc->disk.detaching, 1))
868 * Block the device from being closed and freed until we're finished
871 closure_get(&dc->disk.cl);
873 bch_writeback_queue(dc);
877 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c)
879 uint32_t rtime = cpu_to_le32(get_seconds());
880 struct uuid_entry *u;
881 char buf[BDEVNAME_SIZE];
883 bdevname(dc->bdev, buf);
885 if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))
889 pr_err("Can't attach %s: already attached", buf);
893 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
894 pr_err("Can't attach %s: shutting down", buf);
898 if (dc->sb.block_size < c->sb.block_size) {
900 pr_err("Couldn't attach %s: block size less than set's block size",
905 u = uuid_find(c, dc->sb.uuid);
908 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
909 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
910 memcpy(u->uuid, invalid_uuid, 16);
911 u->invalidated = cpu_to_le32(get_seconds());
916 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
917 pr_err("Couldn't find uuid for %s in set", buf);
921 u = uuid_find_empty(c);
923 pr_err("Not caching %s, no room for UUID", buf);
928 /* Deadlocks since we're called via sysfs...
929 sysfs_remove_file(&dc->kobj, &sysfs_attach);
932 if (bch_is_zero(u->uuid, 16)) {
934 closure_init_stack(&cl);
936 memcpy(u->uuid, dc->sb.uuid, 16);
937 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
938 u->first_reg = u->last_reg = rtime;
941 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
942 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
944 bch_write_bdev_super(dc, &cl);
951 bcache_device_attach(&dc->disk, c, u - c->uuids);
952 list_move(&dc->list, &c->cached_devs);
953 calc_cached_dev_sectors(c);
957 * dc->c must be set before dc->count != 0 - paired with the mb in
960 atomic_set(&dc->count, 1);
962 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
963 atomic_set(&dc->has_dirty, 1);
964 atomic_inc(&dc->count);
965 bch_writeback_queue(dc);
968 bch_cached_dev_run(dc);
969 bcache_device_link(&dc->disk, c, "bdev");
971 pr_info("Caching %s as %s on set %pU",
972 bdevname(dc->bdev, buf), dc->disk.disk->disk_name,
973 dc->disk.c->sb.set_uuid);
977 void bch_cached_dev_release(struct kobject *kobj)
979 struct cached_dev *dc = container_of(kobj, struct cached_dev,
982 module_put(THIS_MODULE);
985 static void cached_dev_free(struct closure *cl)
987 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
989 cancel_delayed_work_sync(&dc->writeback_rate_update);
991 mutex_lock(&bch_register_lock);
993 if (atomic_read(&dc->running))
994 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
995 bcache_device_free(&dc->disk);
998 mutex_unlock(&bch_register_lock);
1000 if (!IS_ERR_OR_NULL(dc->bdev)) {
1001 if (dc->bdev->bd_disk)
1002 blk_sync_queue(bdev_get_queue(dc->bdev));
1004 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1007 wake_up(&unregister_wait);
1009 kobject_put(&dc->disk.kobj);
1012 static void cached_dev_flush(struct closure *cl)
1014 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1015 struct bcache_device *d = &dc->disk;
1017 bch_cache_accounting_destroy(&dc->accounting);
1018 kobject_del(&d->kobj);
1020 continue_at(cl, cached_dev_free, system_wq);
1023 static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
1027 struct request_queue *q = bdev_get_queue(dc->bdev);
1029 __module_get(THIS_MODULE);
1030 INIT_LIST_HEAD(&dc->list);
1031 closure_init(&dc->disk.cl, NULL);
1032 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1033 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1034 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1035 closure_init_unlocked(&dc->sb_write);
1036 INIT_LIST_HEAD(&dc->io_lru);
1037 spin_lock_init(&dc->io_lock);
1038 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1040 dc->sequential_merge = true;
1041 dc->sequential_cutoff = 4 << 20;
1043 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1044 list_add(&io->lru, &dc->io_lru);
1045 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1048 ret = bcache_device_init(&dc->disk, block_size);
1052 set_capacity(dc->disk.disk,
1053 dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
1055 dc->disk.disk->queue->backing_dev_info.ra_pages =
1056 max(dc->disk.disk->queue->backing_dev_info.ra_pages,
1057 q->backing_dev_info.ra_pages);
1059 bch_cached_dev_request_init(dc);
1060 bch_cached_dev_writeback_init(dc);
1064 /* Cached device - bcache superblock */
1066 static void register_bdev(struct cache_sb *sb, struct page *sb_page,
1067 struct block_device *bdev,
1068 struct cached_dev *dc)
1070 char name[BDEVNAME_SIZE];
1071 const char *err = "cannot allocate memory";
1072 struct cache_set *c;
1074 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1076 dc->bdev->bd_holder = dc;
1078 bio_init(&dc->sb_bio);
1079 dc->sb_bio.bi_max_vecs = 1;
1080 dc->sb_bio.bi_io_vec = dc->sb_bio.bi_inline_vecs;
1081 dc->sb_bio.bi_io_vec[0].bv_page = sb_page;
1084 if (cached_dev_init(dc, sb->block_size << 9))
1087 err = "error creating kobject";
1088 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1091 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1094 pr_info("registered backing device %s", bdevname(bdev, name));
1096 list_add(&dc->list, &uncached_devices);
1097 list_for_each_entry(c, &bch_cache_sets, list)
1098 bch_cached_dev_attach(dc, c);
1100 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1101 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
1102 bch_cached_dev_run(dc);
1106 pr_notice("error opening %s: %s", bdevname(bdev, name), err);
1107 bcache_device_stop(&dc->disk);
1110 /* Flash only volumes */
1112 void bch_flash_dev_release(struct kobject *kobj)
1114 struct bcache_device *d = container_of(kobj, struct bcache_device,
1119 static void flash_dev_free(struct closure *cl)
1121 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1122 bcache_device_free(d);
1123 kobject_put(&d->kobj);
1126 static void flash_dev_flush(struct closure *cl)
1128 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1130 bcache_device_unlink(d);
1131 kobject_del(&d->kobj);
1132 continue_at(cl, flash_dev_free, system_wq);
1135 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1137 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1142 closure_init(&d->cl, NULL);
1143 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1145 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1147 if (bcache_device_init(d, block_bytes(c)))
1150 bcache_device_attach(d, c, u - c->uuids);
1151 set_capacity(d->disk, u->sectors);
1152 bch_flash_dev_request_init(d);
1155 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1158 bcache_device_link(d, c, "volume");
1162 kobject_put(&d->kobj);
1166 static int flash_devs_run(struct cache_set *c)
1169 struct uuid_entry *u;
1172 u < c->uuids + c->nr_uuids && !ret;
1174 if (UUID_FLASH_ONLY(u))
1175 ret = flash_dev_run(c, u);
1180 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1182 struct uuid_entry *u;
1184 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1187 u = uuid_find_empty(c);
1189 pr_err("Can't create volume, no room for UUID");
1193 get_random_bytes(u->uuid, 16);
1194 memset(u->label, 0, 32);
1195 u->first_reg = u->last_reg = cpu_to_le32(get_seconds());
1197 SET_UUID_FLASH_ONLY(u, 1);
1198 u->sectors = size >> 9;
1202 return flash_dev_run(c, u);
1208 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1212 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1215 /* XXX: we can be called from atomic context
1216 acquire_console_sem();
1219 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid);
1221 va_start(args, fmt);
1225 printk(", disabling caching\n");
1227 bch_cache_set_unregister(c);
1231 void bch_cache_set_release(struct kobject *kobj)
1233 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1235 module_put(THIS_MODULE);
1238 static void cache_set_free(struct closure *cl)
1240 struct cache_set *c = container_of(cl, struct cache_set, cl);
1244 if (!IS_ERR_OR_NULL(c->debug))
1245 debugfs_remove(c->debug);
1247 bch_open_buckets_free(c);
1248 bch_btree_cache_free(c);
1249 bch_journal_free(c);
1251 for_each_cache(ca, c, i)
1253 kobject_put(&ca->kobj);
1255 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
1256 free_pages((unsigned long) c->sort, ilog2(bucket_pages(c)));
1258 kfree(c->fill_iter);
1260 bioset_free(c->bio_split);
1262 mempool_destroy(c->bio_meta);
1264 mempool_destroy(c->search);
1267 mutex_lock(&bch_register_lock);
1269 mutex_unlock(&bch_register_lock);
1271 pr_info("Cache set %pU unregistered", c->sb.set_uuid);
1272 wake_up(&unregister_wait);
1274 closure_debug_destroy(&c->cl);
1275 kobject_put(&c->kobj);
1278 static void cache_set_flush(struct closure *cl)
1280 struct cache_set *c = container_of(cl, struct cache_set, caching);
1283 /* Shut down allocator threads */
1284 set_bit(CACHE_SET_STOPPING_2, &c->flags);
1285 wake_up_allocators(c);
1287 bch_cache_accounting_destroy(&c->accounting);
1289 kobject_put(&c->internal);
1290 kobject_del(&c->kobj);
1292 if (!IS_ERR_OR_NULL(c->root))
1293 list_add(&c->root->list, &c->btree_cache);
1295 /* Should skip this if we're unregistering because of an error */
1296 list_for_each_entry(b, &c->btree_cache, list)
1297 if (btree_node_dirty(b))
1298 bch_btree_write(b, true, NULL);
1303 static void __cache_set_unregister(struct closure *cl)
1305 struct cache_set *c = container_of(cl, struct cache_set, caching);
1306 struct cached_dev *dc, *t;
1309 mutex_lock(&bch_register_lock);
1311 if (test_bit(CACHE_SET_UNREGISTERING, &c->flags))
1312 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
1313 bch_cached_dev_detach(dc);
1315 for (i = 0; i < c->nr_uuids; i++)
1316 if (c->devices[i] && UUID_FLASH_ONLY(&c->uuids[i]))
1317 bcache_device_stop(c->devices[i]);
1319 mutex_unlock(&bch_register_lock);
1321 continue_at(cl, cache_set_flush, system_wq);
1324 void bch_cache_set_stop(struct cache_set *c)
1326 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1327 closure_queue(&c->caching);
1330 void bch_cache_set_unregister(struct cache_set *c)
1332 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1333 bch_cache_set_stop(c);
1336 #define alloc_bucket_pages(gfp, c) \
1337 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
1339 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1342 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1346 __module_get(THIS_MODULE);
1347 closure_init(&c->cl, NULL);
1348 set_closure_fn(&c->cl, cache_set_free, system_wq);
1350 closure_init(&c->caching, &c->cl);
1351 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1353 /* Maybe create continue_at_noreturn() and use it here? */
1354 closure_set_stopped(&c->cl);
1355 closure_put(&c->cl);
1357 kobject_init(&c->kobj, &bch_cache_set_ktype);
1358 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1360 bch_cache_accounting_init(&c->accounting, &c->cl);
1362 memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1363 c->sb.block_size = sb->block_size;
1364 c->sb.bucket_size = sb->bucket_size;
1365 c->sb.nr_in_set = sb->nr_in_set;
1366 c->sb.last_mount = sb->last_mount;
1367 c->bucket_bits = ilog2(sb->bucket_size);
1368 c->block_bits = ilog2(sb->block_size);
1369 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
1371 c->btree_pages = c->sb.bucket_size / PAGE_SECTORS;
1372 if (c->btree_pages > BTREE_MAX_PAGES)
1373 c->btree_pages = max_t(int, c->btree_pages / 4,
1376 mutex_init(&c->bucket_lock);
1377 mutex_init(&c->fill_lock);
1378 mutex_init(&c->sort_lock);
1379 spin_lock_init(&c->sort_time_lock);
1380 closure_init_unlocked(&c->sb_write);
1381 closure_init_unlocked(&c->uuid_write);
1382 spin_lock_init(&c->btree_read_time_lock);
1383 bch_moving_init_cache_set(c);
1385 INIT_LIST_HEAD(&c->list);
1386 INIT_LIST_HEAD(&c->cached_devs);
1387 INIT_LIST_HEAD(&c->btree_cache);
1388 INIT_LIST_HEAD(&c->btree_cache_freeable);
1389 INIT_LIST_HEAD(&c->btree_cache_freed);
1390 INIT_LIST_HEAD(&c->data_buckets);
1392 c->search = mempool_create_slab_pool(32, bch_search_cache);
1396 iter_size = (sb->bucket_size / sb->block_size + 1) *
1397 sizeof(struct btree_iter_set);
1399 if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) ||
1400 !(c->bio_meta = mempool_create_kmalloc_pool(2,
1401 sizeof(struct bbio) + sizeof(struct bio_vec) *
1402 bucket_pages(c))) ||
1403 !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
1404 !(c->fill_iter = kmalloc(iter_size, GFP_KERNEL)) ||
1405 !(c->sort = alloc_bucket_pages(GFP_KERNEL, c)) ||
1406 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
1407 bch_journal_alloc(c) ||
1408 bch_btree_cache_alloc(c) ||
1409 bch_open_buckets_alloc(c))
1412 c->fill_iter->size = sb->bucket_size / sb->block_size;
1414 c->congested_read_threshold_us = 2000;
1415 c->congested_write_threshold_us = 20000;
1416 c->error_limit = 8 << IO_ERROR_SHIFT;
1420 bch_cache_set_unregister(c);
1424 static void run_cache_set(struct cache_set *c)
1426 const char *err = "cannot allocate memory";
1427 struct cached_dev *dc, *t;
1432 bch_btree_op_init_stack(&op);
1435 for_each_cache(ca, c, i)
1436 c->nbuckets += ca->sb.nbuckets;
1438 if (CACHE_SYNC(&c->sb)) {
1443 err = "cannot allocate memory for journal";
1444 if (bch_journal_read(c, &journal, &op))
1447 pr_debug("btree_journal_read() done");
1449 err = "no journal entries found";
1450 if (list_empty(&journal))
1453 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1455 err = "IO error reading priorities";
1456 for_each_cache(ca, c, i)
1457 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]);
1460 * If prio_read() fails it'll call cache_set_error and we'll
1461 * tear everything down right away, but if we perhaps checked
1462 * sooner we could avoid journal replay.
1467 err = "bad btree root";
1468 if (__bch_ptr_invalid(c, j->btree_level + 1, k))
1471 err = "error reading btree root";
1472 c->root = bch_btree_node_get(c, k, j->btree_level, &op);
1473 if (IS_ERR_OR_NULL(c->root))
1476 list_del_init(&c->root->list);
1477 rw_unlock(true, c->root);
1479 err = uuid_read(c, j, &op.cl);
1483 err = "error in recovery";
1484 if (bch_btree_check(c, &op))
1487 bch_journal_mark(c, &journal);
1488 bch_btree_gc_finish(c);
1489 pr_debug("btree_check() done");
1492 * bcache_journal_next() can't happen sooner, or
1493 * btree_gc_finish() will give spurious errors about last_gc >
1494 * gc_gen - this is a hack but oh well.
1496 bch_journal_next(&c->journal);
1498 err = "error starting allocator thread";
1499 for_each_cache(ca, c, i)
1500 if (bch_cache_allocator_start(ca))
1504 * First place it's safe to allocate: btree_check() and
1505 * btree_gc_finish() have to run before we have buckets to
1506 * allocate, and bch_bucket_alloc_set() might cause a journal
1507 * entry to be written so bcache_journal_next() has to be called
1510 * If the uuids were in the old format we have to rewrite them
1511 * before the next journal entry is written:
1513 if (j->version < BCACHE_JSET_VERSION_UUID)
1516 bch_journal_replay(c, &journal, &op);
1518 pr_notice("invalidating existing data");
1519 /* Don't want invalidate_buckets() to queue a gc yet */
1520 closure_lock(&c->gc, NULL);
1522 for_each_cache(ca, c, i) {
1525 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
1526 2, SB_JOURNAL_BUCKETS);
1528 for (j = 0; j < ca->sb.keys; j++)
1529 ca->sb.d[j] = ca->sb.first_bucket + j;
1532 bch_btree_gc_finish(c);
1534 err = "error starting allocator thread";
1535 for_each_cache(ca, c, i)
1536 if (bch_cache_allocator_start(ca))
1539 mutex_lock(&c->bucket_lock);
1540 for_each_cache(ca, c, i)
1542 mutex_unlock(&c->bucket_lock);
1544 err = "cannot allocate new UUID bucket";
1545 if (__uuid_write(c))
1548 err = "cannot allocate new btree root";
1549 c->root = bch_btree_node_alloc(c, 0, &op.cl);
1550 if (IS_ERR_OR_NULL(c->root))
1553 bkey_copy_key(&c->root->key, &MAX_KEY);
1554 bch_btree_write(c->root, true, &op);
1556 bch_btree_set_root(c->root);
1557 rw_unlock(true, c->root);
1560 * We don't want to write the first journal entry until
1561 * everything is set up - fortunately journal entries won't be
1562 * written until the SET_CACHE_SYNC() here:
1564 SET_CACHE_SYNC(&c->sb, true);
1566 bch_journal_next(&c->journal);
1567 bch_journal_meta(c, &op.cl);
1570 closure_set_stopped(&c->gc.cl);
1571 closure_put(&c->gc.cl);
1574 closure_sync(&op.cl);
1575 c->sb.last_mount = get_seconds();
1576 bcache_write_super(c);
1578 list_for_each_entry_safe(dc, t, &uncached_devices, list)
1579 bch_cached_dev_attach(dc, c);
1585 closure_set_stopped(&c->gc.cl);
1586 closure_put(&c->gc.cl);
1588 closure_sync(&op.cl);
1589 /* XXX: test this, it's broken */
1590 bch_cache_set_error(c, err);
1593 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
1595 return ca->sb.block_size == c->sb.block_size &&
1596 ca->sb.bucket_size == c->sb.block_size &&
1597 ca->sb.nr_in_set == c->sb.nr_in_set;
1600 static const char *register_cache_set(struct cache *ca)
1603 const char *err = "cannot allocate memory";
1604 struct cache_set *c;
1606 list_for_each_entry(c, &bch_cache_sets, list)
1607 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
1608 if (c->cache[ca->sb.nr_this_dev])
1609 return "duplicate cache set member";
1611 if (!can_attach_cache(ca, c))
1612 return "cache sb does not match set";
1614 if (!CACHE_SYNC(&ca->sb))
1615 SET_CACHE_SYNC(&c->sb, false);
1620 c = bch_cache_set_alloc(&ca->sb);
1624 err = "error creating kobject";
1625 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
1626 kobject_add(&c->internal, &c->kobj, "internal"))
1629 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
1632 bch_debug_init_cache_set(c);
1634 list_add(&c->list, &bch_cache_sets);
1636 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
1637 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
1638 sysfs_create_link(&c->kobj, &ca->kobj, buf))
1641 if (ca->sb.seq > c->sb.seq) {
1642 c->sb.version = ca->sb.version;
1643 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
1644 c->sb.flags = ca->sb.flags;
1645 c->sb.seq = ca->sb.seq;
1646 pr_debug("set version = %llu", c->sb.version);
1650 ca->set->cache[ca->sb.nr_this_dev] = ca;
1651 c->cache_by_alloc[c->caches_loaded++] = ca;
1653 if (c->caches_loaded == c->sb.nr_in_set)
1658 bch_cache_set_unregister(c);
1664 void bch_cache_release(struct kobject *kobj)
1666 struct cache *ca = container_of(kobj, struct cache, kobj);
1669 ca->set->cache[ca->sb.nr_this_dev] = NULL;
1671 bch_cache_allocator_exit(ca);
1673 bio_split_pool_free(&ca->bio_split_hook);
1675 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
1676 kfree(ca->prio_buckets);
1679 free_heap(&ca->heap);
1680 free_fifo(&ca->unused);
1681 free_fifo(&ca->free_inc);
1682 free_fifo(&ca->free);
1684 if (ca->sb_bio.bi_inline_vecs[0].bv_page)
1685 put_page(ca->sb_bio.bi_io_vec[0].bv_page);
1687 if (!IS_ERR_OR_NULL(ca->bdev)) {
1688 blk_sync_queue(bdev_get_queue(ca->bdev));
1689 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1693 module_put(THIS_MODULE);
1696 static int cache_alloc(struct cache_sb *sb, struct cache *ca)
1701 __module_get(THIS_MODULE);
1702 kobject_init(&ca->kobj, &bch_cache_ktype);
1704 INIT_LIST_HEAD(&ca->discards);
1706 bio_init(&ca->journal.bio);
1707 ca->journal.bio.bi_max_vecs = 8;
1708 ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs;
1710 free = roundup_pow_of_two(ca->sb.nbuckets) >> 9;
1711 free = max_t(size_t, free, (prio_buckets(ca) + 8) * 2);
1713 if (!init_fifo(&ca->free, free, GFP_KERNEL) ||
1714 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) ||
1715 !init_fifo(&ca->unused, free << 2, GFP_KERNEL) ||
1716 !init_heap(&ca->heap, free << 3, GFP_KERNEL) ||
1717 !(ca->buckets = vzalloc(sizeof(struct bucket) *
1718 ca->sb.nbuckets)) ||
1719 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) *
1721 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)) ||
1722 bio_split_pool_init(&ca->bio_split_hook))
1725 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
1727 for_each_bucket(b, ca)
1728 atomic_set(&b->pin, 0);
1730 if (bch_cache_allocator_init(ca))
1735 kobject_put(&ca->kobj);
1739 static void register_cache(struct cache_sb *sb, struct page *sb_page,
1740 struct block_device *bdev, struct cache *ca)
1742 char name[BDEVNAME_SIZE];
1743 const char *err = "cannot allocate memory";
1745 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
1747 ca->bdev->bd_holder = ca;
1749 bio_init(&ca->sb_bio);
1750 ca->sb_bio.bi_max_vecs = 1;
1751 ca->sb_bio.bi_io_vec = ca->sb_bio.bi_inline_vecs;
1752 ca->sb_bio.bi_io_vec[0].bv_page = sb_page;
1755 if (blk_queue_discard(bdev_get_queue(ca->bdev)))
1756 ca->discard = CACHE_DISCARD(&ca->sb);
1758 if (cache_alloc(sb, ca) != 0)
1761 err = "error creating kobject";
1762 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache"))
1765 err = register_cache_set(ca);
1769 pr_info("registered cache device %s", bdevname(bdev, name));
1772 pr_notice("error opening %s: %s", bdevname(bdev, name), err);
1773 kobject_put(&ca->kobj);
1776 /* Global interfaces/init */
1778 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *,
1779 const char *, size_t);
1781 kobj_attribute_write(register, register_bcache);
1782 kobj_attribute_write(register_quiet, register_bcache);
1784 static bool bch_is_open_backing(struct block_device *bdev) {
1785 struct cache_set *c, *tc;
1786 struct cached_dev *dc, *t;
1788 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
1789 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
1790 if (dc->bdev == bdev)
1792 list_for_each_entry_safe(dc, t, &uncached_devices, list)
1793 if (dc->bdev == bdev)
1798 static bool bch_is_open_cache(struct block_device *bdev) {
1799 struct cache_set *c, *tc;
1803 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
1804 for_each_cache(ca, c, i)
1805 if (ca->bdev == bdev)
1810 static bool bch_is_open(struct block_device *bdev) {
1811 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
1814 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
1815 const char *buffer, size_t size)
1818 const char *err = "cannot allocate memory";
1820 struct cache_sb *sb = NULL;
1821 struct block_device *bdev = NULL;
1822 struct page *sb_page = NULL;
1824 if (!try_module_get(THIS_MODULE))
1827 mutex_lock(&bch_register_lock);
1829 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) ||
1830 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL)))
1833 err = "failed to open device";
1834 bdev = blkdev_get_by_path(strim(path),
1835 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
1838 if (bdev == ERR_PTR(-EBUSY)) {
1839 bdev = lookup_bdev(strim(path));
1840 if (!IS_ERR(bdev) && bch_is_open(bdev))
1841 err = "device already registered";
1843 err = "device busy";
1848 err = "failed to set blocksize";
1849 if (set_blocksize(bdev, 4096))
1852 err = read_super(sb, bdev, &sb_page);
1856 if (SB_IS_BDEV(sb)) {
1857 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
1861 register_bdev(sb, sb_page, bdev, dc);
1863 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
1867 register_cache(sb, sb_page, bdev, ca);
1874 mutex_unlock(&bch_register_lock);
1875 module_put(THIS_MODULE);
1879 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1881 if (attr != &ksysfs_register_quiet)
1882 pr_info("error opening %s: %s", path, err);
1887 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
1889 if (code == SYS_DOWN ||
1891 code == SYS_POWER_OFF) {
1893 unsigned long start = jiffies;
1894 bool stopped = false;
1896 struct cache_set *c, *tc;
1897 struct cached_dev *dc, *tdc;
1899 mutex_lock(&bch_register_lock);
1901 if (list_empty(&bch_cache_sets) &&
1902 list_empty(&uncached_devices))
1905 pr_info("Stopping all devices:");
1907 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
1908 bch_cache_set_stop(c);
1910 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
1911 bcache_device_stop(&dc->disk);
1913 /* What's a condition variable? */
1915 long timeout = start + 2 * HZ - jiffies;
1917 stopped = list_empty(&bch_cache_sets) &&
1918 list_empty(&uncached_devices);
1920 if (timeout < 0 || stopped)
1923 prepare_to_wait(&unregister_wait, &wait,
1924 TASK_UNINTERRUPTIBLE);
1926 mutex_unlock(&bch_register_lock);
1927 schedule_timeout(timeout);
1928 mutex_lock(&bch_register_lock);
1931 finish_wait(&unregister_wait, &wait);
1934 pr_info("All devices stopped");
1936 pr_notice("Timeout waiting for devices to be closed");
1938 mutex_unlock(&bch_register_lock);
1944 static struct notifier_block reboot = {
1945 .notifier_call = bcache_reboot,
1946 .priority = INT_MAX, /* before any real devices */
1949 static void bcache_exit(void)
1952 bch_writeback_exit();
1956 kobject_put(bcache_kobj);
1958 destroy_workqueue(bcache_wq);
1959 unregister_blkdev(bcache_major, "bcache");
1960 unregister_reboot_notifier(&reboot);
1963 static int __init bcache_init(void)
1965 static const struct attribute *files[] = {
1966 &ksysfs_register.attr,
1967 &ksysfs_register_quiet.attr,
1971 mutex_init(&bch_register_lock);
1972 init_waitqueue_head(&unregister_wait);
1973 register_reboot_notifier(&reboot);
1974 closure_debug_init();
1976 bcache_major = register_blkdev(0, "bcache");
1977 if (bcache_major < 0)
1978 return bcache_major;
1980 if (!(bcache_wq = create_workqueue("bcache")) ||
1981 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) ||
1982 sysfs_create_files(bcache_kobj, files) ||
1984 bch_request_init() ||
1985 bch_writeback_init() ||
1986 bch_debug_init(bcache_kobj))
1995 module_exit(bcache_exit);
1996 module_init(bcache_init);