/* * bcache setup/teardown code, and some metadata io - read a superblock and * figure out what to do with it. * * Copyright 2010, 2011 Kent Overstreet * Copyright 2012 Google, Inc. */ #include "bcache.h" #include "btree.h" #include "debug.h" #include "request.h" #include #include #include #include #include #include #include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Kent Overstreet "); static const char bcache_magic[] = { 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca, 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 }; static const char invalid_uuid[] = { 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78, 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99 }; /* Default is -1; we skip past it for struct cached_dev's cache mode */ const char * const bch_cache_modes[] = { "default", "writethrough", "writeback", "writearound", "none", NULL }; struct uuid_entry_v0 { uint8_t uuid[16]; uint8_t label[32]; uint32_t first_reg; uint32_t last_reg; uint32_t invalidated; uint32_t pad; }; static struct kobject *bcache_kobj; struct mutex bch_register_lock; LIST_HEAD(bch_cache_sets); static LIST_HEAD(uncached_devices); static int bcache_major, bcache_minor; static wait_queue_head_t unregister_wait; struct workqueue_struct *bcache_wq; #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) static void bio_split_pool_free(struct bio_split_pool *p) { if (p->bio_split_hook) mempool_destroy(p->bio_split_hook); if (p->bio_split) bioset_free(p->bio_split); } static int bio_split_pool_init(struct bio_split_pool *p) { p->bio_split = bioset_create(4, 0); if (!p->bio_split) return -ENOMEM; p->bio_split_hook = mempool_create_kmalloc_pool(4, sizeof(struct bio_split_hook)); if (!p->bio_split_hook) return -ENOMEM; return 0; } /* Superblock */ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, struct page **res) { const char *err; struct cache_sb *s; struct buffer_head *bh = __bread(bdev, 1, SB_SIZE); unsigned i; if (!bh) return "IO error"; s = (struct cache_sb *) bh->b_data; sb->offset = le64_to_cpu(s->offset); sb->version = le64_to_cpu(s->version); memcpy(sb->magic, s->magic, 16); memcpy(sb->uuid, s->uuid, 16); memcpy(sb->set_uuid, s->set_uuid, 16); memcpy(sb->label, s->label, SB_LABEL_SIZE); sb->flags = le64_to_cpu(s->flags); sb->seq = le64_to_cpu(s->seq); sb->last_mount = le32_to_cpu(s->last_mount); sb->first_bucket = le16_to_cpu(s->first_bucket); sb->keys = le16_to_cpu(s->keys); for (i = 0; i < SB_JOURNAL_BUCKETS; i++) sb->d[i] = le64_to_cpu(s->d[i]); pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u", sb->version, sb->flags, sb->seq, sb->keys); err = "Not a bcache superblock"; if (sb->offset != SB_SECTOR) goto err; if (memcmp(sb->magic, bcache_magic, 16)) goto err; err = "Too many journal buckets"; if (sb->keys > SB_JOURNAL_BUCKETS) goto err; err = "Bad checksum"; if (s->csum != csum_set(s)) goto err; err = "Bad UUID"; if (bch_is_zero(sb->uuid, 16)) goto err; sb->block_size = le16_to_cpu(s->block_size); err = "Superblock block size smaller than device block size"; if (sb->block_size << 9 < bdev_logical_block_size(bdev)) goto err; switch (sb->version) { case BCACHE_SB_VERSION_BDEV: sb->data_offset = BDEV_DATA_START_DEFAULT; break; case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: sb->data_offset = le64_to_cpu(s->data_offset); err = "Bad data offset"; if (sb->data_offset < BDEV_DATA_START_DEFAULT) goto err; break; case BCACHE_SB_VERSION_CDEV: case BCACHE_SB_VERSION_CDEV_WITH_UUID: sb->nbuckets = le64_to_cpu(s->nbuckets); sb->block_size = le16_to_cpu(s->block_size); sb->bucket_size = le16_to_cpu(s->bucket_size); sb->nr_in_set = le16_to_cpu(s->nr_in_set); sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); err = "Too many buckets"; if (sb->nbuckets > LONG_MAX) goto err; err = "Not enough buckets"; if (sb->nbuckets < 1 << 7) goto err; err = "Bad block/bucket size"; if (!is_power_of_2(sb->block_size) || sb->block_size > PAGE_SECTORS || !is_power_of_2(sb->bucket_size) || sb->bucket_size < PAGE_SECTORS) goto err; err = "Invalid superblock: device too small"; if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets) goto err; err = "Bad UUID"; if (bch_is_zero(sb->set_uuid, 16)) goto err; err = "Bad cache device number in set"; if (!sb->nr_in_set || sb->nr_in_set <= sb->nr_this_dev || sb->nr_in_set > MAX_CACHES_PER_SET) goto err; err = "Journal buckets not sequential"; for (i = 0; i < sb->keys; i++) if (sb->d[i] != sb->first_bucket + i) goto err; err = "Too many journal buckets"; if (sb->first_bucket + sb->keys > sb->nbuckets) goto err; err = "Invalid superblock: first bucket comes before end of super"; if (sb->first_bucket * sb->bucket_size < 16) goto err; break; default: err = "Unsupported superblock version"; goto err; } sb->last_mount = get_seconds(); err = NULL; get_page(bh->b_page); *res = bh->b_page; err: put_bh(bh); return err; } static void write_bdev_super_endio(struct bio *bio, int error) { struct cached_dev *dc = bio->bi_private; /* XXX: error checking */ closure_put(&dc->sb_write.cl); } static void __write_super(struct cache_sb *sb, struct bio *bio) { struct cache_sb *out = page_address(bio->bi_io_vec[0].bv_page); unsigned i; bio->bi_sector = SB_SECTOR; bio->bi_rw = REQ_SYNC|REQ_META; bio->bi_size = SB_SIZE; bch_bio_map(bio, NULL); out->offset = cpu_to_le64(sb->offset); out->version = cpu_to_le64(sb->version); memcpy(out->uuid, sb->uuid, 16); memcpy(out->set_uuid, sb->set_uuid, 16); memcpy(out->label, sb->label, SB_LABEL_SIZE); out->flags = cpu_to_le64(sb->flags); out->seq = cpu_to_le64(sb->seq); out->last_mount = cpu_to_le32(sb->last_mount); out->first_bucket = cpu_to_le16(sb->first_bucket); out->keys = cpu_to_le16(sb->keys); for (i = 0; i < sb->keys; i++) out->d[i] = cpu_to_le64(sb->d[i]); out->csum = csum_set(out); pr_debug("ver %llu, flags %llu, seq %llu", sb->version, sb->flags, sb->seq); submit_bio(REQ_WRITE, bio); } void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) { struct closure *cl = &dc->sb_write.cl; struct bio *bio = &dc->sb_bio; closure_lock(&dc->sb_write, parent); bio_reset(bio); bio->bi_bdev = dc->bdev; bio->bi_end_io = write_bdev_super_endio; bio->bi_private = dc; closure_get(cl); __write_super(&dc->sb, bio); closure_return(cl); } static void write_super_endio(struct bio *bio, int error) { struct cache *ca = bio->bi_private; bch_count_io_errors(ca, error, "writing superblock"); closure_put(&ca->set->sb_write.cl); } void bcache_write_super(struct cache_set *c) { struct closure *cl = &c->sb_write.cl; struct cache *ca; unsigned i; closure_lock(&c->sb_write, &c->cl); c->sb.seq++; for_each_cache(ca, c, i) { struct bio *bio = &ca->sb_bio; ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; ca->sb.seq = c->sb.seq; ca->sb.last_mount = c->sb.last_mount; SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb)); bio_reset(bio); bio->bi_bdev = ca->bdev; bio->bi_end_io = write_super_endio; bio->bi_private = ca; closure_get(cl); __write_super(&ca->sb, bio); } closure_return(cl); } /* UUID io */ static void uuid_endio(struct bio *bio, int error) { struct closure *cl = bio->bi_private; struct cache_set *c = container_of(cl, struct cache_set, uuid_write.cl); cache_set_err_on(error, c, "accessing uuids"); bch_bbio_free(bio, c); closure_put(cl); } static void uuid_io(struct cache_set *c, unsigned long rw, struct bkey *k, struct closure *parent) { struct closure *cl = &c->uuid_write.cl; struct uuid_entry *u; unsigned i; BUG_ON(!parent); closure_lock(&c->uuid_write, parent); for (i = 0; i < KEY_PTRS(k); i++) { struct bio *bio = bch_bbio_alloc(c); bio->bi_rw = REQ_SYNC|REQ_META|rw; bio->bi_size = KEY_SIZE(k) << 9; bio->bi_end_io = uuid_endio; bio->bi_private = cl; bch_bio_map(bio, c->uuids); bch_submit_bbio(bio, c, k, i); if (!(rw & WRITE)) break; } pr_debug("%s UUIDs at %s", rw & REQ_WRITE ? "wrote" : "read", pkey(&c->uuid_bucket)); for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) if (!bch_is_zero(u->uuid, 16)) pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u", u - c->uuids, u->uuid, u->label, u->first_reg, u->last_reg, u->invalidated); closure_return(cl); } static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) { struct bkey *k = &j->uuid_bucket; if (__bch_ptr_invalid(c, 1, k)) return "bad uuid pointer"; bkey_copy(&c->uuid_bucket, k); uuid_io(c, READ_SYNC, k, cl); if (j->version < BCACHE_JSET_VERSION_UUIDv1) { struct uuid_entry_v0 *u0 = (void *) c->uuids; struct uuid_entry *u1 = (void *) c->uuids; int i; closure_sync(cl); /* * Since the new uuid entry is bigger than the old, we have to * convert starting at the highest memory address and work down * in order to do it in place */ for (i = c->nr_uuids - 1; i >= 0; --i) { memcpy(u1[i].uuid, u0[i].uuid, 16); memcpy(u1[i].label, u0[i].label, 32); u1[i].first_reg = u0[i].first_reg; u1[i].last_reg = u0[i].last_reg; u1[i].invalidated = u0[i].invalidated; u1[i].flags = 0; u1[i].sectors = 0; } } return NULL; } static int __uuid_write(struct cache_set *c) { BKEY_PADDED(key) k; struct closure cl; closure_init_stack(&cl); lockdep_assert_held(&bch_register_lock); if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, &cl)) return 1; SET_KEY_SIZE(&k.key, c->sb.bucket_size); uuid_io(c, REQ_WRITE, &k.key, &cl); closure_sync(&cl); bkey_copy(&c->uuid_bucket, &k.key); __bkey_put(c, &k.key); return 0; } int bch_uuid_write(struct cache_set *c) { int ret = __uuid_write(c); if (!ret) bch_journal_meta(c, NULL); return ret; } static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid) { struct uuid_entry *u; for (u = c->uuids; u < c->uuids + c->nr_uuids; u++) if (!memcmp(u->uuid, uuid, 16)) return u; return NULL; } static struct uuid_entry *uuid_find_empty(struct cache_set *c) { static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; return uuid_find(c, zero_uuid); } /* * Bucket priorities/gens: * * For each bucket, we store on disk its * 8 bit gen * 16 bit priority * * See alloc.c for an explanation of the gen. The priority is used to implement * lru (and in the future other) cache replacement policies; for most purposes * it's just an opaque integer. * * The gens and the priorities don't have a whole lot to do with each other, and * it's actually the gens that must be written out at specific times - it's no * big deal if the priorities don't get written, if we lose them we just reuse * buckets in suboptimal order. * * On disk they're stored in a packed array, and in as many buckets are required * to fit them all. The buckets we use to store them form a list; the journal * header points to the first bucket, the first bucket points to the second * bucket, et cetera. * * This code is used by the allocation code; periodically (whenever it runs out * of buckets to allocate from) the allocation code will invalidate some * buckets, but it can't use those buckets until their new gens are safely on * disk. */ static void prio_endio(struct bio *bio, int error) { struct cache *ca = bio->bi_private; cache_set_err_on(error, ca->set, "accessing priorities"); bch_bbio_free(bio, ca->set); closure_put(&ca->prio); } static void prio_io(struct cache *ca, uint64_t bucket, unsigned long rw) { struct closure *cl = &ca->prio; struct bio *bio = bch_bbio_alloc(ca->set); closure_init_stack(cl); bio->bi_sector = bucket * ca->sb.bucket_size; bio->bi_bdev = ca->bdev; bio->bi_rw = REQ_SYNC|REQ_META|rw; bio->bi_size = bucket_bytes(ca); bio->bi_end_io = prio_endio; bio->bi_private = ca; bch_bio_map(bio, ca->disk_buckets); closure_bio_submit(bio, &ca->prio, ca); closure_sync(cl); } #define buckets_free(c) "free %zu, free_inc %zu, unused %zu", \ fifo_used(&c->free), fifo_used(&c->free_inc), fifo_used(&c->unused) void bch_prio_write(struct cache *ca) { int i; struct bucket *b; struct closure cl; closure_init_stack(&cl); lockdep_assert_held(&ca->set->bucket_lock); for (b = ca->buckets; b < ca->buckets + ca->sb.nbuckets; b++) b->disk_gen = b->gen; ca->disk_buckets->seq++; atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), &ca->meta_sectors_written); pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free), fifo_used(&ca->free_inc), fifo_used(&ca->unused)); blktrace_msg(ca, "Starting priorities: " buckets_free(ca)); for (i = prio_buckets(ca) - 1; i >= 0; --i) { long bucket; struct prio_set *p = ca->disk_buckets; struct bucket_disk *d = p->data; struct bucket_disk *end = d + prios_per_bucket(ca); for (b = ca->buckets + i * prios_per_bucket(ca); b < ca->buckets + ca->sb.nbuckets && d < end; b++, d++) { d->prio = cpu_to_le16(b->prio); d->gen = b->gen; } p->next_bucket = ca->prio_buckets[i + 1]; p->magic = pset_magic(ca); p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8); bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, &cl); BUG_ON(bucket == -1); mutex_unlock(&ca->set->bucket_lock); prio_io(ca, bucket, REQ_WRITE); mutex_lock(&ca->set->bucket_lock); ca->prio_buckets[i] = bucket; atomic_dec_bug(&ca->buckets[bucket].pin); } mutex_unlock(&ca->set->bucket_lock); bch_journal_meta(ca->set, &cl); closure_sync(&cl); mutex_lock(&ca->set->bucket_lock); ca->need_save_prio = 0; /* * Don't want the old priorities to get garbage collected until after we * finish writing the new ones, and they're journalled */ for (i = 0; i < prio_buckets(ca); i++) ca->prio_last_buckets[i] = ca->prio_buckets[i]; } static void prio_read(struct cache *ca, uint64_t bucket) { struct prio_set *p = ca->disk_buckets; struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d; struct bucket *b; unsigned bucket_nr = 0; for (b = ca->buckets; b < ca->buckets + ca->sb.nbuckets; b++, d++) { if (d == end) { ca->prio_buckets[bucket_nr] = bucket; ca->prio_last_buckets[bucket_nr] = bucket; bucket_nr++; prio_io(ca, bucket, READ_SYNC); if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) pr_warn("bad csum reading priorities"); if (p->magic != pset_magic(ca)) pr_warn("bad magic reading priorities"); bucket = p->next_bucket; d = p->data; } b->prio = le16_to_cpu(d->prio); b->gen = b->disk_gen = b->last_gc = b->gc_gen = d->gen; } } /* Bcache device */ static int open_dev(struct block_device *b, fmode_t mode) { struct bcache_device *d = b->bd_disk->private_data; if (atomic_read(&d->closing)) return -ENXIO; closure_get(&d->cl); return 0; } static void release_dev(struct gendisk *b, fmode_t mode) { struct bcache_device *d = b->private_data; closure_put(&d->cl); } static int ioctl_dev(struct block_device *b, fmode_t mode, unsigned int cmd, unsigned long arg) { struct bcache_device *d = b->bd_disk->private_data; return d->ioctl(d, mode, cmd, arg); } static const struct block_device_operations bcache_ops = { .open = open_dev, .release = release_dev, .ioctl = ioctl_dev, .owner = THIS_MODULE, }; void bcache_device_stop(struct bcache_device *d) { if (!atomic_xchg(&d->closing, 1)) closure_queue(&d->cl); } static void bcache_device_unlink(struct bcache_device *d) { unsigned i; struct cache *ca; sysfs_remove_link(&d->c->kobj, d->name); sysfs_remove_link(&d->kobj, "cache"); for_each_cache(ca, d->c, i) bd_unlink_disk_holder(ca->bdev, d->disk); } static void bcache_device_link(struct bcache_device *d, struct cache_set *c, const char *name) { unsigned i; struct cache *ca; for_each_cache(ca, d->c, i) bd_link_disk_holder(ca->bdev, d->disk); snprintf(d->name, BCACHEDEVNAME_SIZE, "%s%u", name, d->id); WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") || sysfs_create_link(&c->kobj, &d->kobj, d->name), "Couldn't create device <-> cache set symlinks"); } static void bcache_device_detach(struct bcache_device *d) { lockdep_assert_held(&bch_register_lock); if (atomic_read(&d->detaching)) { struct uuid_entry *u = d->c->uuids + d->id; SET_UUID_FLASH_ONLY(u, 0); memcpy(u->uuid, invalid_uuid, 16); u->invalidated = cpu_to_le32(get_seconds()); bch_uuid_write(d->c); atomic_set(&d->detaching, 0); } if (!d->flush_done) bcache_device_unlink(d); d->c->devices[d->id] = NULL; closure_put(&d->c->caching); d->c = NULL; } static void bcache_device_attach(struct bcache_device *d, struct cache_set *c, unsigned id) { BUG_ON(test_bit(CACHE_SET_STOPPING, &c->flags)); d->id = id; d->c = c; c->devices[id] = d; closure_get(&c->caching); } static void bcache_device_free(struct bcache_device *d) { lockdep_assert_held(&bch_register_lock); pr_info("%s stopped", d->disk->disk_name); if (d->c) bcache_device_detach(d); if (d->disk && d->disk->flags & GENHD_FL_UP) del_gendisk(d->disk); if (d->disk && d->disk->queue) blk_cleanup_queue(d->disk->queue); if (d->disk) put_disk(d->disk); bio_split_pool_free(&d->bio_split_hook); if (d->unaligned_bvec) mempool_destroy(d->unaligned_bvec); if (d->bio_split) bioset_free(d->bio_split); closure_debug_destroy(&d->cl); } static int bcache_device_init(struct bcache_device *d, unsigned block_size) { struct request_queue *q; if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) || !(d->unaligned_bvec = mempool_create_kmalloc_pool(1, sizeof(struct bio_vec) * BIO_MAX_PAGES)) || bio_split_pool_init(&d->bio_split_hook) || !(d->disk = alloc_disk(1)) || !(q = blk_alloc_queue(GFP_KERNEL))) return -ENOMEM; snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor); d->disk->major = bcache_major; d->disk->first_minor = bcache_minor++; d->disk->fops = &bcache_ops; d->disk->private_data = d; blk_queue_make_request(q, NULL); d->disk->queue = q; q->queuedata = d; q->backing_dev_info.congested_data = d; q->limits.max_hw_sectors = UINT_MAX; q->limits.max_sectors = UINT_MAX; q->limits.max_segment_size = UINT_MAX; q->limits.max_segments = BIO_MAX_PAGES; q->limits.max_discard_sectors = UINT_MAX; q->limits.io_min = block_size; q->limits.logical_block_size = block_size; q->limits.physical_block_size = block_size; set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags); set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags); blk_queue_flush(q, REQ_FLUSH|REQ_FUA); return 0; } /* Cached device */ static void calc_cached_dev_sectors(struct cache_set *c) { uint64_t sectors = 0; struct cached_dev *dc; list_for_each_entry(dc, &c->cached_devs, list) sectors += bdev_sectors(dc->bdev); c->cached_dev_sectors = sectors; } void bch_cached_dev_run(struct cached_dev *dc) { struct bcache_device *d = &dc->disk; if (atomic_xchg(&dc->running, 1)) return; if (!d->c && BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) { struct closure cl; closure_init_stack(&cl); SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE); bch_write_bdev_super(dc, &cl); closure_sync(&cl); } add_disk(d->disk); bd_link_disk_holder(dc->bdev, dc->disk.disk); #if 0 char *env[] = { "SYMLINK=label" , NULL }; kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); #endif if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) pr_debug("error creating sysfs link"); } static void cached_dev_detach_finish(struct work_struct *w) { struct cached_dev *dc = container_of(w, struct cached_dev, detach); char buf[BDEVNAME_SIZE]; struct closure cl; closure_init_stack(&cl); BUG_ON(!atomic_read(&dc->disk.detaching)); BUG_ON(atomic_read(&dc->count)); mutex_lock(&bch_register_lock); memset(&dc->sb.set_uuid, 0, 16); SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); bch_write_bdev_super(dc, &cl); closure_sync(&cl); bcache_device_detach(&dc->disk); list_move(&dc->list, &uncached_devices); mutex_unlock(&bch_register_lock); pr_info("Caching disabled for %s", bdevname(dc->bdev, buf)); /* Drop ref we took in cached_dev_detach() */ closure_put(&dc->disk.cl); } void bch_cached_dev_detach(struct cached_dev *dc) { lockdep_assert_held(&bch_register_lock); if (atomic_read(&dc->disk.closing)) return; if (atomic_xchg(&dc->disk.detaching, 1)) return; /* * Block the device from being closed and freed until we're finished * detaching */ closure_get(&dc->disk.cl); bch_writeback_queue(dc); cached_dev_put(dc); } int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c) { uint32_t rtime = cpu_to_le32(get_seconds()); struct uuid_entry *u; char buf[BDEVNAME_SIZE]; bdevname(dc->bdev, buf); if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)) return -ENOENT; if (dc->disk.c) { pr_err("Can't attach %s: already attached", buf); return -EINVAL; } if (test_bit(CACHE_SET_STOPPING, &c->flags)) { pr_err("Can't attach %s: shutting down", buf); return -EINVAL; } if (dc->sb.block_size < c->sb.block_size) { /* Will die */ pr_err("Couldn't attach %s: block size less than set's block size", buf); return -EINVAL; } u = uuid_find(c, dc->sb.uuid); if (u && (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE || BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) { memcpy(u->uuid, invalid_uuid, 16); u->invalidated = cpu_to_le32(get_seconds()); u = NULL; } if (!u) { if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { pr_err("Couldn't find uuid for %s in set", buf); return -ENOENT; } u = uuid_find_empty(c); if (!u) { pr_err("Not caching %s, no room for UUID", buf); return -EINVAL; } } /* Deadlocks since we're called via sysfs... sysfs_remove_file(&dc->kobj, &sysfs_attach); */ if (bch_is_zero(u->uuid, 16)) { struct closure cl; closure_init_stack(&cl); memcpy(u->uuid, dc->sb.uuid, 16); memcpy(u->label, dc->sb.label, SB_LABEL_SIZE); u->first_reg = u->last_reg = rtime; bch_uuid_write(c); memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16); SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); bch_write_bdev_super(dc, &cl); closure_sync(&cl); } else { u->last_reg = rtime; bch_uuid_write(c); } bcache_device_attach(&dc->disk, c, u - c->uuids); list_move(&dc->list, &c->cached_devs); calc_cached_dev_sectors(c); smp_wmb(); /* * dc->c must be set before dc->count != 0 - paired with the mb in * cached_dev_get() */ atomic_set(&dc->count, 1); if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { atomic_set(&dc->has_dirty, 1); atomic_inc(&dc->count); bch_writeback_queue(dc); } bch_cached_dev_run(dc); bcache_device_link(&dc->disk, c, "bdev"); pr_info("Caching %s as %s on set %pU", bdevname(dc->bdev, buf), dc->disk.disk->disk_name, dc->disk.c->sb.set_uuid); return 0; } void bch_cached_dev_release(struct kobject *kobj) { struct cached_dev *dc = container_of(kobj, struct cached_dev, disk.kobj); kfree(dc); module_put(THIS_MODULE); } static void cached_dev_free(struct closure *cl) { struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); cancel_delayed_work_sync(&dc->writeback_rate_update); mutex_lock(&bch_register_lock); if (atomic_read(&dc->running)) bd_unlink_disk_holder(dc->bdev, dc->disk.disk); bcache_device_free(&dc->disk); list_del(&dc->list); mutex_unlock(&bch_register_lock); if (!IS_ERR_OR_NULL(dc->bdev)) { if (dc->bdev->bd_disk) blk_sync_queue(bdev_get_queue(dc->bdev)); blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } wake_up(&unregister_wait); kobject_put(&dc->disk.kobj); } static void cached_dev_flush(struct closure *cl) { struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl); struct bcache_device *d = &dc->disk; mutex_lock(&bch_register_lock); d->flush_done = 1; if (d->c) bcache_device_unlink(d); mutex_unlock(&bch_register_lock); bch_cache_accounting_destroy(&dc->accounting); kobject_del(&d->kobj); continue_at(cl, cached_dev_free, system_wq); } static int cached_dev_init(struct cached_dev *dc, unsigned block_size) { int ret; struct io *io; struct request_queue *q = bdev_get_queue(dc->bdev); __module_get(THIS_MODULE); INIT_LIST_HEAD(&dc->list); closure_init(&dc->disk.cl, NULL); set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq); kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype); INIT_WORK(&dc->detach, cached_dev_detach_finish); closure_init_unlocked(&dc->sb_write); INIT_LIST_HEAD(&dc->io_lru); spin_lock_init(&dc->io_lock); bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); dc->sequential_merge = true; dc->sequential_cutoff = 4 << 20; for (io = dc->io; io < dc->io + RECENT_IO; io++) { list_add(&io->lru, &dc->io_lru); hlist_add_head(&io->hash, dc->io_hash + RECENT_IO); } ret = bcache_device_init(&dc->disk, block_size); if (ret) return ret; set_capacity(dc->disk.disk, dc->bdev->bd_part->nr_sects - dc->sb.data_offset); dc->disk.disk->queue->backing_dev_info.ra_pages = max(dc->disk.disk->queue->backing_dev_info.ra_pages, q->backing_dev_info.ra_pages); bch_cached_dev_request_init(dc); bch_cached_dev_writeback_init(dc); return 0; } /* Cached device - bcache superblock */ static void register_bdev(struct cache_sb *sb, struct page *sb_page, struct block_device *bdev, struct cached_dev *dc) { char name[BDEVNAME_SIZE]; const char *err = "cannot allocate memory"; struct cache_set *c; memcpy(&dc->sb, sb, sizeof(struct cache_sb)); dc->bdev = bdev; dc->bdev->bd_holder = dc; bio_init(&dc->sb_bio); dc->sb_bio.bi_max_vecs = 1; dc->sb_bio.bi_io_vec = dc->sb_bio.bi_inline_vecs; dc->sb_bio.bi_io_vec[0].bv_page = sb_page; get_page(sb_page); if (cached_dev_init(dc, sb->block_size << 9)) goto err; err = "error creating kobject"; if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) goto err; if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) goto err; pr_info("registered backing device %s", bdevname(bdev, name)); list_add(&dc->list, &uncached_devices); list_for_each_entry(c, &bch_cache_sets, list) bch_cached_dev_attach(dc, c); if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) bch_cached_dev_run(dc); return; err: pr_notice("error opening %s: %s", bdevname(bdev, name), err); bcache_device_stop(&dc->disk); } /* Flash only volumes */ void bch_flash_dev_release(struct kobject *kobj) { struct bcache_device *d = container_of(kobj, struct bcache_device, kobj); kfree(d); } static void flash_dev_free(struct closure *cl) { struct bcache_device *d = container_of(cl, struct bcache_device, cl); bcache_device_free(d); kobject_put(&d->kobj); } static void flash_dev_flush(struct closure *cl) { struct bcache_device *d = container_of(cl, struct bcache_device, cl); bcache_device_unlink(d); kobject_del(&d->kobj); continue_at(cl, flash_dev_free, system_wq); } static int flash_dev_run(struct cache_set *c, struct uuid_entry *u) { struct bcache_device *d = kzalloc(sizeof(struct bcache_device), GFP_KERNEL); if (!d) return -ENOMEM; closure_init(&d->cl, NULL); set_closure_fn(&d->cl, flash_dev_flush, system_wq); kobject_init(&d->kobj, &bch_flash_dev_ktype); if (bcache_device_init(d, block_bytes(c))) goto err; bcache_device_attach(d, c, u - c->uuids); set_capacity(d->disk, u->sectors); bch_flash_dev_request_init(d); add_disk(d->disk); if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache")) goto err; bcache_device_link(d, c, "volume"); return 0; err: kobject_put(&d->kobj); return -ENOMEM; } static int flash_devs_run(struct cache_set *c) { int ret = 0; struct uuid_entry *u; for (u = c->uuids; u < c->uuids + c->nr_uuids && !ret; u++) if (UUID_FLASH_ONLY(u)) ret = flash_dev_run(c, u); return ret; } int bch_flash_dev_create(struct cache_set *c, uint64_t size) { struct uuid_entry *u; if (test_bit(CACHE_SET_STOPPING, &c->flags)) return -EINTR; u = uuid_find_empty(c); if (!u) { pr_err("Can't create volume, no room for UUID"); return -EINVAL; } get_random_bytes(u->uuid, 16); memset(u->label, 0, 32); u->first_reg = u->last_reg = cpu_to_le32(get_seconds()); SET_UUID_FLASH_ONLY(u, 1); u->sectors = size >> 9; bch_uuid_write(c); return flash_dev_run(c, u); } /* Cache set */ __printf(2, 3) bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) { va_list args; if (test_bit(CACHE_SET_STOPPING, &c->flags)) return false; /* XXX: we can be called from atomic context acquire_console_sem(); */ printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid); va_start(args, fmt); vprintk(fmt, args); va_end(args); printk(", disabling caching\n"); bch_cache_set_unregister(c); return true; } void bch_cache_set_release(struct kobject *kobj) { struct cache_set *c = container_of(kobj, struct cache_set, kobj); kfree(c); module_put(THIS_MODULE); } static void cache_set_free(struct closure *cl) { struct cache_set *c = container_of(cl, struct cache_set, cl); struct cache *ca; unsigned i; if (!IS_ERR_OR_NULL(c->debug)) debugfs_remove(c->debug); bch_open_buckets_free(c); bch_btree_cache_free(c); bch_journal_free(c); for_each_cache(ca, c, i) if (ca) kobject_put(&ca->kobj); free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); free_pages((unsigned long) c->sort, ilog2(bucket_pages(c))); kfree(c->fill_iter); if (c->bio_split) bioset_free(c->bio_split); if (c->bio_meta) mempool_destroy(c->bio_meta); if (c->search) mempool_destroy(c->search); kfree(c->devices); mutex_lock(&bch_register_lock); list_del(&c->list); mutex_unlock(&bch_register_lock); pr_info("Cache set %pU unregistered", c->sb.set_uuid); wake_up(&unregister_wait); closure_debug_destroy(&c->cl); kobject_put(&c->kobj); } static void cache_set_flush(struct closure *cl) { struct cache_set *c = container_of(cl, struct cache_set, caching); struct btree *b; /* Shut down allocator threads */ set_bit(CACHE_SET_STOPPING_2, &c->flags); wake_up(&c->alloc_wait); if (!c) closure_return(cl); bch_cache_accounting_destroy(&c->accounting); kobject_put(&c->internal); kobject_del(&c->kobj); if (!IS_ERR_OR_NULL(c->root)) list_add(&c->root->list, &c->btree_cache); /* Should skip this if we're unregistering because of an error */ list_for_each_entry(b, &c->btree_cache, list) if (btree_node_dirty(b)) bch_btree_write(b, true, NULL); closure_return(cl); } static void __cache_set_unregister(struct closure *cl) { struct cache_set *c = container_of(cl, struct cache_set, caching); struct cached_dev *dc; size_t i; mutex_lock(&bch_register_lock); for (i = 0; i < c->nr_uuids; i++) if (c->devices[i]) { if (!UUID_FLASH_ONLY(&c->uuids[i]) && test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { dc = container_of(c->devices[i], struct cached_dev, disk); bch_cached_dev_detach(dc); } else { bcache_device_stop(c->devices[i]); } } mutex_unlock(&bch_register_lock); continue_at(cl, cache_set_flush, system_wq); } void bch_cache_set_stop(struct cache_set *c) { if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags)) closure_queue(&c->caching); } void bch_cache_set_unregister(struct cache_set *c) { set_bit(CACHE_SET_UNREGISTERING, &c->flags); bch_cache_set_stop(c); } #define alloc_bucket_pages(gfp, c) \ ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) { int iter_size; struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); if (!c) return NULL; __module_get(THIS_MODULE); closure_init(&c->cl, NULL); set_closure_fn(&c->cl, cache_set_free, system_wq); closure_init(&c->caching, &c->cl); set_closure_fn(&c->caching, __cache_set_unregister, system_wq); /* Maybe create continue_at_noreturn() and use it here? */ closure_set_stopped(&c->cl); closure_put(&c->cl); kobject_init(&c->kobj, &bch_cache_set_ktype); kobject_init(&c->internal, &bch_cache_set_internal_ktype); bch_cache_accounting_init(&c->accounting, &c->cl); memcpy(c->sb.set_uuid, sb->set_uuid, 16); c->sb.block_size = sb->block_size; c->sb.bucket_size = sb->bucket_size; c->sb.nr_in_set = sb->nr_in_set; c->sb.last_mount = sb->last_mount; c->bucket_bits = ilog2(sb->bucket_size); c->block_bits = ilog2(sb->block_size); c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry); c->btree_pages = c->sb.bucket_size / PAGE_SECTORS; if (c->btree_pages > BTREE_MAX_PAGES) c->btree_pages = max_t(int, c->btree_pages / 4, BTREE_MAX_PAGES); init_waitqueue_head(&c->alloc_wait); mutex_init(&c->bucket_lock); mutex_init(&c->fill_lock); mutex_init(&c->sort_lock); spin_lock_init(&c->sort_time_lock); closure_init_unlocked(&c->sb_write); closure_init_unlocked(&c->uuid_write); spin_lock_init(&c->btree_read_time_lock); bch_moving_init_cache_set(c); INIT_LIST_HEAD(&c->list); INIT_LIST_HEAD(&c->cached_devs); INIT_LIST_HEAD(&c->btree_cache); INIT_LIST_HEAD(&c->btree_cache_freeable); INIT_LIST_HEAD(&c->btree_cache_freed); INIT_LIST_HEAD(&c->data_buckets); c->search = mempool_create_slab_pool(32, bch_search_cache); if (!c->search) goto err; iter_size = (sb->bucket_size / sb->block_size + 1) * sizeof(struct btree_iter_set); if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) || !(c->bio_meta = mempool_create_kmalloc_pool(2, sizeof(struct bbio) + sizeof(struct bio_vec) * bucket_pages(c))) || !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) || !(c->fill_iter = kmalloc(iter_size, GFP_KERNEL)) || !(c->sort = alloc_bucket_pages(GFP_KERNEL, c)) || !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || bch_journal_alloc(c) || bch_btree_cache_alloc(c) || bch_open_buckets_alloc(c)) goto err; c->fill_iter->size = sb->bucket_size / sb->block_size; c->congested_read_threshold_us = 2000; c->congested_write_threshold_us = 20000; c->error_limit = 8 << IO_ERROR_SHIFT; return c; err: bch_cache_set_unregister(c); return NULL; } static void run_cache_set(struct cache_set *c) { const char *err = "cannot allocate memory"; struct cached_dev *dc, *t; struct cache *ca; unsigned i; struct btree_op op; bch_btree_op_init_stack(&op); op.lock = SHRT_MAX; for_each_cache(ca, c, i) c->nbuckets += ca->sb.nbuckets; if (CACHE_SYNC(&c->sb)) { LIST_HEAD(journal); struct bkey *k; struct jset *j; err = "cannot allocate memory for journal"; if (bch_journal_read(c, &journal, &op)) goto err; pr_debug("btree_journal_read() done"); err = "no journal entries found"; if (list_empty(&journal)) goto err; j = &list_entry(journal.prev, struct journal_replay, list)->j; err = "IO error reading priorities"; for_each_cache(ca, c, i) prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]); /* * If prio_read() fails it'll call cache_set_error and we'll * tear everything down right away, but if we perhaps checked * sooner we could avoid journal replay. */ k = &j->btree_root; err = "bad btree root"; if (__bch_ptr_invalid(c, j->btree_level + 1, k)) goto err; err = "error reading btree root"; c->root = bch_btree_node_get(c, k, j->btree_level, &op); if (IS_ERR_OR_NULL(c->root)) goto err; list_del_init(&c->root->list); rw_unlock(true, c->root); err = uuid_read(c, j, &op.cl); if (err) goto err; err = "error in recovery"; if (bch_btree_check(c, &op)) goto err; bch_journal_mark(c, &journal); bch_btree_gc_finish(c); pr_debug("btree_check() done"); /* * bcache_journal_next() can't happen sooner, or * btree_gc_finish() will give spurious errors about last_gc > * gc_gen - this is a hack but oh well. */ bch_journal_next(&c->journal); for_each_cache(ca, c, i) closure_call(&ca->alloc, bch_allocator_thread, system_wq, &c->cl); /* * First place it's safe to allocate: btree_check() and * btree_gc_finish() have to run before we have buckets to * allocate, and bch_bucket_alloc_set() might cause a journal * entry to be written so bcache_journal_next() has to be called * first. * * If the uuids were in the old format we have to rewrite them * before the next journal entry is written: */ if (j->version < BCACHE_JSET_VERSION_UUID) __uuid_write(c); bch_journal_replay(c, &journal, &op); } else { pr_notice("invalidating existing data"); /* Don't want invalidate_buckets() to queue a gc yet */ closure_lock(&c->gc, NULL); for_each_cache(ca, c, i) { unsigned j; ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7, 2, SB_JOURNAL_BUCKETS); for (j = 0; j < ca->sb.keys; j++) ca->sb.d[j] = ca->sb.first_bucket + j; } bch_btree_gc_finish(c); for_each_cache(ca, c, i) closure_call(&ca->alloc, bch_allocator_thread, ca->alloc_workqueue, &c->cl); mutex_lock(&c->bucket_lock); for_each_cache(ca, c, i) bch_prio_write(ca); mutex_unlock(&c->bucket_lock); wake_up(&c->alloc_wait); err = "cannot allocate new UUID bucket"; if (__uuid_write(c)) goto err_unlock_gc; err = "cannot allocate new btree root"; c->root = bch_btree_node_alloc(c, 0, &op.cl); if (IS_ERR_OR_NULL(c->root)) goto err_unlock_gc; bkey_copy_key(&c->root->key, &MAX_KEY); bch_btree_write(c->root, true, &op); bch_btree_set_root(c->root); rw_unlock(true, c->root); /* * We don't want to write the first journal entry until * everything is set up - fortunately journal entries won't be * written until the SET_CACHE_SYNC() here: */ SET_CACHE_SYNC(&c->sb, true); bch_journal_next(&c->journal); bch_journal_meta(c, &op.cl); /* Unlock */ closure_set_stopped(&c->gc.cl); closure_put(&c->gc.cl); } closure_sync(&op.cl); c->sb.last_mount = get_seconds(); bcache_write_super(c); list_for_each_entry_safe(dc, t, &uncached_devices, list) bch_cached_dev_attach(dc, c); flash_devs_run(c); return; err_unlock_gc: closure_set_stopped(&c->gc.cl); closure_put(&c->gc.cl); err: closure_sync(&op.cl); /* XXX: test this, it's broken */ bch_cache_set_error(c, err); } static bool can_attach_cache(struct cache *ca, struct cache_set *c) { return ca->sb.block_size == c->sb.block_size && ca->sb.bucket_size == c->sb.block_size && ca->sb.nr_in_set == c->sb.nr_in_set; } static const char *register_cache_set(struct cache *ca) { char buf[12]; const char *err = "cannot allocate memory"; struct cache_set *c; list_for_each_entry(c, &bch_cache_sets, list) if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) { if (c->cache[ca->sb.nr_this_dev]) return "duplicate cache set member"; if (!can_attach_cache(ca, c)) return "cache sb does not match set"; if (!CACHE_SYNC(&ca->sb)) SET_CACHE_SYNC(&c->sb, false); goto found; } c = bch_cache_set_alloc(&ca->sb); if (!c) return err; err = "error creating kobject"; if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) || kobject_add(&c->internal, &c->kobj, "internal")) goto err; if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) goto err; bch_debug_init_cache_set(c); list_add(&c->list, &bch_cache_sets); found: sprintf(buf, "cache%i", ca->sb.nr_this_dev); if (sysfs_create_link(&ca->kobj, &c->kobj, "set") || sysfs_create_link(&c->kobj, &ca->kobj, buf)) goto err; if (ca->sb.seq > c->sb.seq) { c->sb.version = ca->sb.version; memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); c->sb.flags = ca->sb.flags; c->sb.seq = ca->sb.seq; pr_debug("set version = %llu", c->sb.version); } ca->set = c; ca->set->cache[ca->sb.nr_this_dev] = ca; c->cache_by_alloc[c->caches_loaded++] = ca; if (c->caches_loaded == c->sb.nr_in_set) run_cache_set(c); return NULL; err: bch_cache_set_unregister(c); return err; } /* Cache device */ void bch_cache_release(struct kobject *kobj) { struct cache *ca = container_of(kobj, struct cache, kobj); if (ca->set) ca->set->cache[ca->sb.nr_this_dev] = NULL; bch_cache_allocator_exit(ca); bio_split_pool_free(&ca->bio_split_hook); if (ca->alloc_workqueue) destroy_workqueue(ca->alloc_workqueue); free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); kfree(ca->prio_buckets); vfree(ca->buckets); free_heap(&ca->heap); free_fifo(&ca->unused); free_fifo(&ca->free_inc); free_fifo(&ca->free); if (ca->sb_bio.bi_inline_vecs[0].bv_page) put_page(ca->sb_bio.bi_io_vec[0].bv_page); if (!IS_ERR_OR_NULL(ca->bdev)) { blk_sync_queue(bdev_get_queue(ca->bdev)); blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } kfree(ca); module_put(THIS_MODULE); } static int cache_alloc(struct cache_sb *sb, struct cache *ca) { size_t free; struct bucket *b; __module_get(THIS_MODULE); kobject_init(&ca->kobj, &bch_cache_ktype); INIT_LIST_HEAD(&ca->discards); bio_init(&ca->journal.bio); ca->journal.bio.bi_max_vecs = 8; ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs; free = roundup_pow_of_two(ca->sb.nbuckets) >> 9; free = max_t(size_t, free, (prio_buckets(ca) + 8) * 2); if (!init_fifo(&ca->free, free, GFP_KERNEL) || !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || !init_fifo(&ca->unused, free << 2, GFP_KERNEL) || !init_heap(&ca->heap, free << 3, GFP_KERNEL) || !(ca->buckets = vzalloc(sizeof(struct bucket) * ca->sb.nbuckets)) || !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 2, GFP_KERNEL)) || !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)) || !(ca->alloc_workqueue = alloc_workqueue("bch_allocator", 0, 1)) || bio_split_pool_init(&ca->bio_split_hook)) return -ENOMEM; ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); for_each_bucket(b, ca) atomic_set(&b->pin, 0); if (bch_cache_allocator_init(ca)) goto err; return 0; err: kobject_put(&ca->kobj); return -ENOMEM; } static void register_cache(struct cache_sb *sb, struct page *sb_page, struct block_device *bdev, struct cache *ca) { char name[BDEVNAME_SIZE]; const char *err = "cannot allocate memory"; memcpy(&ca->sb, sb, sizeof(struct cache_sb)); ca->bdev = bdev; ca->bdev->bd_holder = ca; bio_init(&ca->sb_bio); ca->sb_bio.bi_max_vecs = 1; ca->sb_bio.bi_io_vec = ca->sb_bio.bi_inline_vecs; ca->sb_bio.bi_io_vec[0].bv_page = sb_page; get_page(sb_page); if (blk_queue_discard(bdev_get_queue(ca->bdev))) ca->discard = CACHE_DISCARD(&ca->sb); if (cache_alloc(sb, ca) != 0) goto err; err = "error creating kobject"; if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) goto err; err = register_cache_set(ca); if (err) goto err; pr_info("registered cache device %s", bdevname(bdev, name)); return; err: pr_notice("error opening %s: %s", bdevname(bdev, name), err); kobject_put(&ca->kobj); } /* Global interfaces/init */ static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, const char *, size_t); kobj_attribute_write(register, register_bcache); kobj_attribute_write(register_quiet, register_bcache); static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, const char *buffer, size_t size) { ssize_t ret = size; const char *err = "cannot allocate memory"; char *path = NULL; struct cache_sb *sb = NULL; struct block_device *bdev = NULL; struct page *sb_page = NULL; if (!try_module_get(THIS_MODULE)) return -EBUSY; mutex_lock(&bch_register_lock); if (!(path = kstrndup(buffer, size, GFP_KERNEL)) || !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL))) goto err; err = "failed to open device"; bdev = blkdev_get_by_path(strim(path), FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); if (IS_ERR(bdev)) { if (bdev == ERR_PTR(-EBUSY)) err = "device busy"; goto err; } err = "failed to set blocksize"; if (set_blocksize(bdev, 4096)) goto err_close; err = read_super(sb, bdev, &sb_page); if (err) goto err_close; if (SB_IS_BDEV(sb)) { struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); if (!dc) goto err_close; register_bdev(sb, sb_page, bdev, dc); } else { struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); if (!ca) goto err_close; register_cache(sb, sb_page, bdev, ca); } out: if (sb_page) put_page(sb_page); kfree(sb); kfree(path); mutex_unlock(&bch_register_lock); module_put(THIS_MODULE); return ret; err_close: blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); err: if (attr != &ksysfs_register_quiet) pr_info("error opening %s: %s", path, err); ret = -EINVAL; goto out; } static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) { if (code == SYS_DOWN || code == SYS_HALT || code == SYS_POWER_OFF) { DEFINE_WAIT(wait); unsigned long start = jiffies; bool stopped = false; struct cache_set *c, *tc; struct cached_dev *dc, *tdc; mutex_lock(&bch_register_lock); if (list_empty(&bch_cache_sets) && list_empty(&uncached_devices)) goto out; pr_info("Stopping all devices:"); list_for_each_entry_safe(c, tc, &bch_cache_sets, list) bch_cache_set_stop(c); list_for_each_entry_safe(dc, tdc, &uncached_devices, list) bcache_device_stop(&dc->disk); /* What's a condition variable? */ while (1) { long timeout = start + 2 * HZ - jiffies; stopped = list_empty(&bch_cache_sets) && list_empty(&uncached_devices); if (timeout < 0 || stopped) break; prepare_to_wait(&unregister_wait, &wait, TASK_UNINTERRUPTIBLE); mutex_unlock(&bch_register_lock); schedule_timeout(timeout); mutex_lock(&bch_register_lock); } finish_wait(&unregister_wait, &wait); if (stopped) pr_info("All devices stopped"); else pr_notice("Timeout waiting for devices to be closed"); out: mutex_unlock(&bch_register_lock); } return NOTIFY_DONE; } static struct notifier_block reboot = { .notifier_call = bcache_reboot, .priority = INT_MAX, /* before any real devices */ }; static void bcache_exit(void) { bch_debug_exit(); bch_writeback_exit(); bch_request_exit(); bch_btree_exit(); if (bcache_kobj) kobject_put(bcache_kobj); if (bcache_wq) destroy_workqueue(bcache_wq); unregister_blkdev(bcache_major, "bcache"); unregister_reboot_notifier(&reboot); } static int __init bcache_init(void) { static const struct attribute *files[] = { &ksysfs_register.attr, &ksysfs_register_quiet.attr, NULL }; mutex_init(&bch_register_lock); init_waitqueue_head(&unregister_wait); register_reboot_notifier(&reboot); closure_debug_init(); bcache_major = register_blkdev(0, "bcache"); if (bcache_major < 0) { unregister_reboot_notifier(&reboot); return bcache_major; } if (!(bcache_wq = create_workqueue("bcache")) || !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) || sysfs_create_files(bcache_kobj, files) || bch_btree_init() || bch_request_init() || bch_writeback_init() || bch_debug_init(bcache_kobj)) goto err; return 0; err: bcache_exit(); return -ENOMEM; } module_exit(bcache_exit); module_init(bcache_init);