diff options
Diffstat (limited to 'drivers/md/bcache/super.c')
| -rw-r--r-- | drivers/md/bcache/super.c | 2941 |
1 files changed, 2941 insertions, 0 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c new file mode 100644 index 000000000..70e5bd896 --- /dev/null +++ b/drivers/md/bcache/super.c @@ -0,0 +1,2941 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * bcache setup/teardown code, and some metadata io - read a superblock and + * figure out what to do with it. + * + * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> + * Copyright 2012 Google, Inc. + */ + +#include "bcache.h" +#include "btree.h" +#include "debug.h" +#include "extents.h" +#include "request.h" +#include "writeback.h" +#include "features.h" + +#include <linux/blkdev.h> +#include <linux/pagemap.h> +#include <linux/debugfs.h> +#include <linux/idr.h> +#include <linux/kthread.h> +#include <linux/workqueue.h> +#include <linux/module.h> +#include <linux/random.h> +#include <linux/reboot.h> +#include <linux/sysfs.h> + +unsigned int bch_cutoff_writeback; +unsigned int bch_cutoff_writeback_sync; + +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 +}; + +static struct kobject *bcache_kobj; +struct mutex bch_register_lock; +bool bcache_is_reboot; +LIST_HEAD(bch_cache_sets); +static LIST_HEAD(uncached_devices); + +static int bcache_major; +static DEFINE_IDA(bcache_device_idx); +static wait_queue_head_t unregister_wait; +struct workqueue_struct *bcache_wq; +struct workqueue_struct *bch_flush_wq; +struct workqueue_struct *bch_journal_wq; + + +#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) +/* limitation of partitions number on single bcache device */ +#define BCACHE_MINORS 128 +/* limitation of bcache devices number on single system */ +#define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS) + +/* Superblock */ + +static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s) +{ + unsigned int bucket_size = le16_to_cpu(s->bucket_size); + + if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) { + if (bch_has_feature_large_bucket(sb)) { + unsigned int max, order; + + max = sizeof(unsigned int) * BITS_PER_BYTE - 1; + order = le16_to_cpu(s->bucket_size); + /* + * bcache tool will make sure the overflow won't + * happen, an error message here is enough. + */ + if (order > max) + pr_err("Bucket size (1 << %u) overflows\n", + order); + bucket_size = 1 << order; + } else if (bch_has_feature_obso_large_bucket(sb)) { + bucket_size += + le16_to_cpu(s->obso_bucket_size_hi) << 16; + } + } + + return bucket_size; +} + +static const char *read_super_common(struct cache_sb *sb, struct block_device *bdev, + struct cache_sb_disk *s) +{ + const char *err; + unsigned int i; + + sb->first_bucket= le16_to_cpu(s->first_bucket); + sb->nbuckets = le64_to_cpu(s->nbuckets); + sb->bucket_size = get_bucket_size(sb, s); + + 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 journal buckets"; + if (sb->keys > SB_JOURNAL_BUCKETS) + goto err; + + 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 size (not power of 2)"; + if (!is_power_of_2(sb->block_size)) + goto err; + + err = "Bad block size (larger than page size)"; + if (sb->block_size > PAGE_SECTORS) + goto err; + + err = "Bad bucket size (not power of 2)"; + if (!is_power_of_2(sb->bucket_size)) + goto err; + + err = "Bad bucket size (smaller than page size)"; + if (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; + + err = NULL; +err: + return err; +} + + +static const char *read_super(struct cache_sb *sb, struct block_device *bdev, + struct cache_sb_disk **res) +{ + const char *err; + struct cache_sb_disk *s; + struct page *page; + unsigned int i; + + page = read_cache_page_gfp(bdev->bd_inode->i_mapping, + SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL); + if (IS_ERR(page)) + return "IO error"; + s = page_address(page) + offset_in_page(SB_OFFSET); + + 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->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\n", + sb->version, sb->flags, sb->seq, sb->keys); + + err = "Not a bcache superblock (bad offset)"; + if (sb->offset != SB_SECTOR) + goto err; + + err = "Not a bcache superblock (bad magic)"; + if (memcmp(sb->magic, bcache_magic, 16)) + 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: + case BCACHE_SB_VERSION_BDEV_WITH_FEATURES: + 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: + err = read_super_common(sb, bdev, s); + if (err) + goto err; + break; + case BCACHE_SB_VERSION_CDEV_WITH_FEATURES: + /* + * Feature bits are needed in read_super_common(), + * convert them firstly. + */ + sb->feature_compat = le64_to_cpu(s->feature_compat); + sb->feature_incompat = le64_to_cpu(s->feature_incompat); + sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat); + + /* Check incompatible features */ + err = "Unsupported compatible feature found"; + if (bch_has_unknown_compat_features(sb)) + goto err; + + err = "Unsupported read-only compatible feature found"; + if (bch_has_unknown_ro_compat_features(sb)) + goto err; + + err = "Unsupported incompatible feature found"; + if (bch_has_unknown_incompat_features(sb)) + goto err; + + err = read_super_common(sb, bdev, s); + if (err) + goto err; + break; + default: + err = "Unsupported superblock version"; + goto err; + } + + sb->last_mount = (u32)ktime_get_real_seconds(); + *res = s; + return NULL; +err: + put_page(page); + return err; +} + +static void write_bdev_super_endio(struct bio *bio) +{ + struct cached_dev *dc = bio->bi_private; + + if (bio->bi_status) + bch_count_backing_io_errors(dc, bio); + + closure_put(&dc->sb_write); +} + +static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out, + struct bio *bio) +{ + unsigned int i; + + bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META; + bio->bi_iter.bi_sector = SB_SECTOR; + __bio_add_page(bio, virt_to_page(out), SB_SIZE, + offset_in_page(out)); + + out->offset = cpu_to_le64(sb->offset); + + 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]); + + if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) { + out->feature_compat = cpu_to_le64(sb->feature_compat); + out->feature_incompat = cpu_to_le64(sb->feature_incompat); + out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat); + } + + out->version = cpu_to_le64(sb->version); + out->csum = csum_set(out); + + pr_debug("ver %llu, flags %llu, seq %llu\n", + sb->version, sb->flags, sb->seq); + + submit_bio(bio); +} + +static void bch_write_bdev_super_unlock(struct closure *cl) +{ + struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write); + + up(&dc->sb_write_mutex); +} + +void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) +{ + struct closure *cl = &dc->sb_write; + struct bio *bio = &dc->sb_bio; + + down(&dc->sb_write_mutex); + closure_init(cl, parent); + + bio_init(bio, dc->bdev, dc->sb_bv, 1, 0); + bio->bi_end_io = write_bdev_super_endio; + bio->bi_private = dc; + + closure_get(cl); + /* I/O request sent to backing device */ + __write_super(&dc->sb, dc->sb_disk, bio); + + closure_return_with_destructor(cl, bch_write_bdev_super_unlock); +} + +static void write_super_endio(struct bio *bio) +{ + struct cache *ca = bio->bi_private; + + /* is_read = 0 */ + bch_count_io_errors(ca, bio->bi_status, 0, + "writing superblock"); + closure_put(&ca->set->sb_write); +} + +static void bcache_write_super_unlock(struct closure *cl) +{ + struct cache_set *c = container_of(cl, struct cache_set, sb_write); + + up(&c->sb_write_mutex); +} + +void bcache_write_super(struct cache_set *c) +{ + struct closure *cl = &c->sb_write; + struct cache *ca = c->cache; + struct bio *bio = &ca->sb_bio; + unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID; + + down(&c->sb_write_mutex); + closure_init(cl, &c->cl); + + ca->sb.seq++; + + if (ca->sb.version < version) + ca->sb.version = version; + + bio_init(bio, ca->bdev, ca->sb_bv, 1, 0); + bio->bi_end_io = write_super_endio; + bio->bi_private = ca; + + closure_get(cl); + __write_super(&ca->sb, ca->sb_disk, bio); + + closure_return_with_destructor(cl, bcache_write_super_unlock); +} + +/* UUID io */ + +static void uuid_endio(struct bio *bio) +{ + struct closure *cl = bio->bi_private; + struct cache_set *c = container_of(cl, struct cache_set, uuid_write); + + cache_set_err_on(bio->bi_status, c, "accessing uuids"); + bch_bbio_free(bio, c); + closure_put(cl); +} + +static void uuid_io_unlock(struct closure *cl) +{ + struct cache_set *c = container_of(cl, struct cache_set, uuid_write); + + up(&c->uuid_write_mutex); +} + +static void uuid_io(struct cache_set *c, blk_opf_t opf, struct bkey *k, + struct closure *parent) +{ + struct closure *cl = &c->uuid_write; + struct uuid_entry *u; + unsigned int i; + char buf[80]; + + BUG_ON(!parent); + down(&c->uuid_write_mutex); + closure_init(cl, parent); + + for (i = 0; i < KEY_PTRS(k); i++) { + struct bio *bio = bch_bbio_alloc(c); + + bio->bi_opf = opf | REQ_SYNC | REQ_META; + bio->bi_iter.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 ((opf & REQ_OP_MASK) != REQ_OP_WRITE) + break; + } + + bch_extent_to_text(buf, sizeof(buf), k); + pr_debug("%s UUIDs at %s\n", (opf & REQ_OP_MASK) == REQ_OP_WRITE ? + "wrote" : "read", buf); + + 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\n", + u - c->uuids, u->uuid, u->label, + u->first_reg, u->last_reg, u->invalidated); + + closure_return_with_destructor(cl, uuid_io_unlock); +} + +static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl) +{ + struct bkey *k = &j->uuid_bucket; + + if (__bch_btree_ptr_invalid(c, k)) + return "bad uuid pointer"; + + bkey_copy(&c->uuid_bucket, k); + uuid_io(c, REQ_OP_READ, 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; + struct cache *ca = c->cache; + unsigned int size; + + closure_init_stack(&cl); + lockdep_assert_held(&bch_register_lock); + + if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true)) + return 1; + + size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS; + SET_KEY_SIZE(&k.key, size); + uuid_io(c, REQ_OP_WRITE, &k.key, &cl); + closure_sync(&cl); + + /* Only one bucket used for uuid write */ + atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written); + + 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) +{ + struct cache *ca = bio->bi_private; + + cache_set_err_on(bio->bi_status, ca->set, "accessing priorities"); + bch_bbio_free(bio, ca->set); + closure_put(&ca->prio); +} + +static void prio_io(struct cache *ca, uint64_t bucket, blk_opf_t opf) +{ + struct closure *cl = &ca->prio; + struct bio *bio = bch_bbio_alloc(ca->set); + + closure_init_stack(cl); + + bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size; + bio_set_dev(bio, ca->bdev); + bio->bi_iter.bi_size = meta_bucket_bytes(&ca->sb); + + bio->bi_end_io = prio_endio; + bio->bi_private = ca; + bio->bi_opf = opf | REQ_SYNC | REQ_META; + bch_bio_map(bio, ca->disk_buckets); + + closure_bio_submit(ca->set, bio, &ca->prio); + closure_sync(cl); +} + +int bch_prio_write(struct cache *ca, bool wait) +{ + int i; + struct bucket *b; + struct closure cl; + + pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n", + fifo_used(&ca->free[RESERVE_PRIO]), + fifo_used(&ca->free[RESERVE_NONE]), + fifo_used(&ca->free_inc)); + + /* + * Pre-check if there are enough free buckets. In the non-blocking + * scenario it's better to fail early rather than starting to allocate + * buckets and do a cleanup later in case of failure. + */ + if (!wait) { + size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) + + fifo_used(&ca->free[RESERVE_NONE]); + if (prio_buckets(ca) > avail) + return -ENOMEM; + } + + closure_init_stack(&cl); + + lockdep_assert_held(&ca->set->bucket_lock); + + ca->disk_buckets->seq++; + + atomic_long_add(ca->sb.bucket_size * prio_buckets(ca), + &ca->meta_sectors_written); + + 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->sb); + p->csum = bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8); + + bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait); + BUG_ON(bucket == -1); + + mutex_unlock(&ca->set->bucket_lock); + prio_io(ca, bucket, REQ_OP_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); + + /* + * 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++) { + if (ca->prio_last_buckets[i]) + __bch_bucket_free(ca, + &ca->buckets[ca->prio_last_buckets[i]]); + + ca->prio_last_buckets[i] = ca->prio_buckets[i]; + } + return 0; +} + +static int 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 int bucket_nr = 0; + int ret = -EIO; + + 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, REQ_OP_READ); + + if (p->csum != + bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) { + pr_warn("bad csum reading priorities\n"); + goto out; + } + + if (p->magic != pset_magic(&ca->sb)) { + pr_warn("bad magic reading priorities\n"); + goto out; + } + + bucket = p->next_bucket; + d = p->data; + } + + b->prio = le16_to_cpu(d->prio); + b->gen = b->last_gc = d->gen; + } + + ret = 0; +out: + return ret; +} + +/* Bcache device */ + +static int open_dev(struct block_device *b, fmode_t mode) +{ + struct bcache_device *d = b->bd_disk->private_data; + + if (test_bit(BCACHE_DEV_CLOSING, &d->flags)) + 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_cached_ops = { + .submit_bio = cached_dev_submit_bio, + .open = open_dev, + .release = release_dev, + .ioctl = ioctl_dev, + .owner = THIS_MODULE, +}; + +static const struct block_device_operations bcache_flash_ops = { + .submit_bio = flash_dev_submit_bio, + .open = open_dev, + .release = release_dev, + .ioctl = ioctl_dev, + .owner = THIS_MODULE, +}; + +void bcache_device_stop(struct bcache_device *d) +{ + if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags)) + /* + * closure_fn set to + * - cached device: cached_dev_flush() + * - flash dev: flash_dev_flush() + */ + closure_queue(&d->cl); +} + +static void bcache_device_unlink(struct bcache_device *d) +{ + lockdep_assert_held(&bch_register_lock); + + if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) { + struct cache *ca = d->c->cache; + + sysfs_remove_link(&d->c->kobj, d->name); + sysfs_remove_link(&d->kobj, "cache"); + + bd_unlink_disk_holder(ca->bdev, d->disk); + } +} + +static void bcache_device_link(struct bcache_device *d, struct cache_set *c, + const char *name) +{ + struct cache *ca = c->cache; + int ret; + + bd_link_disk_holder(ca->bdev, d->disk); + + snprintf(d->name, BCACHEDEVNAME_SIZE, + "%s%u", name, d->id); + + ret = sysfs_create_link(&d->kobj, &c->kobj, "cache"); + if (ret < 0) + pr_err("Couldn't create device -> cache set symlink\n"); + + ret = sysfs_create_link(&c->kobj, &d->kobj, d->name); + if (ret < 0) + pr_err("Couldn't create cache set -> device symlink\n"); + + clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags); +} + +static void bcache_device_detach(struct bcache_device *d) +{ + lockdep_assert_held(&bch_register_lock); + + atomic_dec(&d->c->attached_dev_nr); + + if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) { + 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((u32)ktime_get_real_seconds()); + bch_uuid_write(d->c); + } + + 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 int id) +{ + d->id = id; + d->c = c; + c->devices[id] = d; + + if (id >= c->devices_max_used) + c->devices_max_used = id + 1; + + closure_get(&c->caching); +} + +static inline int first_minor_to_idx(int first_minor) +{ + return (first_minor/BCACHE_MINORS); +} + +static inline int idx_to_first_minor(int idx) +{ + return (idx * BCACHE_MINORS); +} + +static void bcache_device_free(struct bcache_device *d) +{ + struct gendisk *disk = d->disk; + + lockdep_assert_held(&bch_register_lock); + + if (disk) + pr_info("%s stopped\n", disk->disk_name); + else + pr_err("bcache device (NULL gendisk) stopped\n"); + + if (d->c) + bcache_device_detach(d); + + if (disk) { + ida_simple_remove(&bcache_device_idx, + first_minor_to_idx(disk->first_minor)); + put_disk(disk); + } + + bioset_exit(&d->bio_split); + kvfree(d->full_dirty_stripes); + kvfree(d->stripe_sectors_dirty); + + closure_debug_destroy(&d->cl); +} + +static int bcache_device_init(struct bcache_device *d, unsigned int block_size, + sector_t sectors, struct block_device *cached_bdev, + const struct block_device_operations *ops) +{ + struct request_queue *q; + const size_t max_stripes = min_t(size_t, INT_MAX, + SIZE_MAX / sizeof(atomic_t)); + uint64_t n; + int idx; + + if (!d->stripe_size) + d->stripe_size = 1 << 31; + else if (d->stripe_size < BCH_MIN_STRIPE_SZ) + d->stripe_size = roundup(BCH_MIN_STRIPE_SZ, d->stripe_size); + + n = DIV_ROUND_UP_ULL(sectors, d->stripe_size); + if (!n || n > max_stripes) { + pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n", + n); + return -ENOMEM; + } + d->nr_stripes = n; + + n = d->nr_stripes * sizeof(atomic_t); + d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL); + if (!d->stripe_sectors_dirty) + return -ENOMEM; + + n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long); + d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL); + if (!d->full_dirty_stripes) + goto out_free_stripe_sectors_dirty; + + idx = ida_simple_get(&bcache_device_idx, 0, + BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); + if (idx < 0) + goto out_free_full_dirty_stripes; + + if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), + BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) + goto out_ida_remove; + + d->disk = blk_alloc_disk(NUMA_NO_NODE); + if (!d->disk) + goto out_bioset_exit; + + set_capacity(d->disk, sectors); + snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx); + + d->disk->major = bcache_major; + d->disk->first_minor = idx_to_first_minor(idx); + d->disk->minors = BCACHE_MINORS; + d->disk->fops = ops; + d->disk->private_data = d; + + q = d->disk->queue; + 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_VECS; + blk_queue_max_discard_sectors(q, UINT_MAX); + q->limits.discard_granularity = 512; + q->limits.io_min = block_size; + q->limits.logical_block_size = block_size; + q->limits.physical_block_size = block_size; + + if (q->limits.logical_block_size > PAGE_SIZE && cached_bdev) { + /* + * This should only happen with BCACHE_SB_VERSION_BDEV. + * Block/page size is checked for BCACHE_SB_VERSION_CDEV. + */ + pr_info("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n", + d->disk->disk_name, q->limits.logical_block_size, + PAGE_SIZE, bdev_logical_block_size(cached_bdev)); + + /* This also adjusts physical block size/min io size if needed */ + blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev)); + } + + blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); + blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); + + blk_queue_write_cache(q, true, true); + + return 0; + +out_bioset_exit: + bioset_exit(&d->bio_split); +out_ida_remove: + ida_simple_remove(&bcache_device_idx, idx); +out_free_full_dirty_stripes: + kvfree(d->full_dirty_stripes); +out_free_stripe_sectors_dirty: + kvfree(d->stripe_sectors_dirty); + return -ENOMEM; + +} + +/* 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_nr_sectors(dc->bdev); + + c->cached_dev_sectors = sectors; +} + +#define BACKING_DEV_OFFLINE_TIMEOUT 5 +static int cached_dev_status_update(void *arg) +{ + struct cached_dev *dc = arg; + struct request_queue *q; + + /* + * If this delayed worker is stopping outside, directly quit here. + * dc->io_disable might be set via sysfs interface, so check it + * here too. + */ + while (!kthread_should_stop() && !dc->io_disable) { + q = bdev_get_queue(dc->bdev); + if (blk_queue_dying(q)) + dc->offline_seconds++; + else + dc->offline_seconds = 0; + + if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) { + pr_err("%pg: device offline for %d seconds\n", + dc->bdev, + BACKING_DEV_OFFLINE_TIMEOUT); + pr_err("%s: disable I/O request due to backing device offline\n", + dc->disk.name); + dc->io_disable = true; + /* let others know earlier that io_disable is true */ + smp_mb(); + bcache_device_stop(&dc->disk); + break; + } + schedule_timeout_interruptible(HZ); + } + + wait_for_kthread_stop(); + return 0; +} + + +int bch_cached_dev_run(struct cached_dev *dc) +{ + int ret = 0; + struct bcache_device *d = &dc->disk; + char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL); + char *env[] = { + "DRIVER=bcache", + kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), + kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""), + NULL, + }; + + if (dc->io_disable) { + pr_err("I/O disabled on cached dev %pg\n", dc->bdev); + ret = -EIO; + goto out; + } + + if (atomic_xchg(&dc->running, 1)) { + pr_info("cached dev %pg is running already\n", dc->bdev); + ret = -EBUSY; + goto out; + } + + 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); + } + + ret = add_disk(d->disk); + if (ret) + goto out; + bd_link_disk_holder(dc->bdev, dc->disk.disk); + /* + * won't show up in the uevent file, use udevadm monitor -e instead + * only class / kset properties are persistent + */ + kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); + + 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_err("Couldn't create bcache dev <-> disk sysfs symlinks\n"); + ret = -ENOMEM; + goto out; + } + + dc->status_update_thread = kthread_run(cached_dev_status_update, + dc, "bcache_status_update"); + if (IS_ERR(dc->status_update_thread)) { + pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n"); + } + +out: + kfree(env[1]); + kfree(env[2]); + kfree(buf); + return ret; +} + +/* + * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed + * work dc->writeback_rate_update is running. Wait until the routine + * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to + * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out + * seconds, give up waiting here and continue to cancel it too. + */ +static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) +{ + int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ; + + do { + if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING, + &dc->disk.flags)) + break; + time_out--; + schedule_timeout_interruptible(1); + } while (time_out > 0); + + if (time_out == 0) + pr_warn("give up waiting for dc->writeback_write_update to quit\n"); + + cancel_delayed_work_sync(&dc->writeback_rate_update); +} + +static void cached_dev_detach_finish(struct work_struct *w) +{ + struct cached_dev *dc = container_of(w, struct cached_dev, detach); + struct cache_set *c = dc->disk.c; + + BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); + BUG_ON(refcount_read(&dc->count)); + + + if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) + cancel_writeback_rate_update_dwork(dc); + + if (!IS_ERR_OR_NULL(dc->writeback_thread)) { + kthread_stop(dc->writeback_thread); + dc->writeback_thread = NULL; + } + + mutex_lock(&bch_register_lock); + + bcache_device_detach(&dc->disk); + list_move(&dc->list, &uncached_devices); + calc_cached_dev_sectors(c); + + clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags); + clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags); + + mutex_unlock(&bch_register_lock); + + pr_info("Caching disabled for %pg\n", dc->bdev); + + /* 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 (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) + return; + + if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) + 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, + uint8_t *set_uuid) +{ + uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds()); + struct uuid_entry *u; + struct cached_dev *exist_dc, *t; + int ret = 0; + + if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) || + (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16))) + return -ENOENT; + + if (dc->disk.c) { + pr_err("Can't attach %pg: already attached\n", dc->bdev); + return -EINVAL; + } + + if (test_bit(CACHE_SET_STOPPING, &c->flags)) { + pr_err("Can't attach %pg: shutting down\n", dc->bdev); + return -EINVAL; + } + + if (dc->sb.block_size < c->cache->sb.block_size) { + /* Will die */ + pr_err("Couldn't attach %pg: block size less than set's block size\n", + dc->bdev); + return -EINVAL; + } + + /* Check whether already attached */ + list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { + if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { + pr_err("Tried to attach %pg but duplicate UUID already attached\n", + dc->bdev); + + 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((u32)ktime_get_real_seconds()); + u = NULL; + } + + if (!u) { + if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { + pr_err("Couldn't find uuid for %pg in set\n", dc->bdev); + return -ENOENT; + } + + u = uuid_find_empty(c); + if (!u) { + pr_err("Not caching %pg, no room for UUID\n", dc->bdev); + 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->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); + + /* + * dc->c must be set before dc->count != 0 - paired with the mb in + * cached_dev_get() + */ + smp_wmb(); + refcount_set(&dc->count, 1); + + /* Block writeback thread, but spawn it */ + down_write(&dc->writeback_lock); + if (bch_cached_dev_writeback_start(dc)) { + up_write(&dc->writeback_lock); + pr_err("Couldn't start writeback facilities for %s\n", + dc->disk.disk->disk_name); + return -ENOMEM; + } + + if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { + atomic_set(&dc->has_dirty, 1); + bch_writeback_queue(dc); + } + + bch_sectors_dirty_init(&dc->disk); + + ret = bch_cached_dev_run(dc); + if (ret && (ret != -EBUSY)) { + up_write(&dc->writeback_lock); + /* + * bch_register_lock is held, bcache_device_stop() is not + * able to be directly called. The kthread and kworker + * created previously in bch_cached_dev_writeback_start() + * have to be stopped manually here. + */ + kthread_stop(dc->writeback_thread); + cancel_writeback_rate_update_dwork(dc); + pr_err("Couldn't run cached device %pg\n", dc->bdev); + return ret; + } + + bcache_device_link(&dc->disk, c, "bdev"); + atomic_inc(&c->attached_dev_nr); + + if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) { + pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n"); + pr_err("Please update to the latest bcache-tools to create the cache device\n"); + set_disk_ro(dc->disk.disk, 1); + } + + /* Allow the writeback thread to proceed */ + up_write(&dc->writeback_lock); + + pr_info("Caching %pg as %s on set %pU\n", + dc->bdev, + dc->disk.disk->disk_name, + dc->disk.c->set_uuid); + return 0; +} + +/* when dc->disk.kobj released */ +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); + + if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) + cancel_writeback_rate_update_dwork(dc); + + if (!IS_ERR_OR_NULL(dc->writeback_thread)) + kthread_stop(dc->writeback_thread); + if (!IS_ERR_OR_NULL(dc->status_update_thread)) + kthread_stop(dc->status_update_thread); + + mutex_lock(&bch_register_lock); + + if (atomic_read(&dc->running)) { + bd_unlink_disk_holder(dc->bdev, dc->disk.disk); + del_gendisk(dc->disk.disk); + } + bcache_device_free(&dc->disk); + list_del(&dc->list); + + mutex_unlock(&bch_register_lock); + + if (dc->sb_disk) + put_page(virt_to_page(dc->sb_disk)); + + if (!IS_ERR_OR_NULL(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); + 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 int 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); + sema_init(&dc->sb_write_mutex, 1); + INIT_LIST_HEAD(&dc->io_lru); + spin_lock_init(&dc->io_lock); + bch_cache_accounting_init(&dc->accounting, &dc->disk.cl); + + 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); + } + + dc->disk.stripe_size = q->limits.io_opt >> 9; + + if (dc->disk.stripe_size) + dc->partial_stripes_expensive = + q->limits.raid_partial_stripes_expensive; + + ret = bcache_device_init(&dc->disk, block_size, + bdev_nr_sectors(dc->bdev) - dc->sb.data_offset, + dc->bdev, &bcache_cached_ops); + if (ret) + return ret; + + blk_queue_io_opt(dc->disk.disk->queue, + max(queue_io_opt(dc->disk.disk->queue), queue_io_opt(q))); + + atomic_set(&dc->io_errors, 0); + dc->io_disable = false; + dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT; + /* default to auto */ + dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO; + + bch_cached_dev_request_init(dc); + bch_cached_dev_writeback_init(dc); + return 0; +} + +/* Cached device - bcache superblock */ + +static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk, + struct block_device *bdev, + struct cached_dev *dc) +{ + const char *err = "cannot allocate memory"; + struct cache_set *c; + int ret = -ENOMEM; + + memcpy(&dc->sb, sb, sizeof(struct cache_sb)); + dc->bdev = bdev; + dc->bdev->bd_holder = dc; + dc->sb_disk = sb_disk; + + if (cached_dev_init(dc, sb->block_size << 9)) + goto err; + + err = "error creating kobject"; + if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache")) + goto err; + if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj)) + goto err; + + pr_info("registered backing device %pg\n", dc->bdev); + + list_add(&dc->list, &uncached_devices); + /* attach to a matched cache set if it exists */ + list_for_each_entry(c, &bch_cache_sets, list) + bch_cached_dev_attach(dc, c, NULL); + + if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE || + BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) { + err = "failed to run cached device"; + ret = bch_cached_dev_run(dc); + if (ret) + goto err; + } + + return 0; +err: + pr_notice("error %pg: %s\n", dc->bdev, err); + bcache_device_stop(&dc->disk); + return ret; +} + +/* Flash only volumes */ + +/* When d->kobj released */ +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); + + mutex_lock(&bch_register_lock); + atomic_long_sub(bcache_dev_sectors_dirty(d), + &d->c->flash_dev_dirty_sectors); + del_gendisk(d->disk); + bcache_device_free(d); + mutex_unlock(&bch_register_lock); + kobject_put(&d->kobj); +} + +static void flash_dev_flush(struct closure *cl) +{ + struct bcache_device *d = container_of(cl, struct bcache_device, cl); + + mutex_lock(&bch_register_lock); + bcache_device_unlink(d); + mutex_unlock(&bch_register_lock); + 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) +{ + int err = -ENOMEM; + struct bcache_device *d = kzalloc(sizeof(struct bcache_device), + GFP_KERNEL); + if (!d) + goto err_ret; + + 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->cache), u->sectors, + NULL, &bcache_flash_ops)) + goto err; + + bcache_device_attach(d, c, u - c->uuids); + bch_sectors_dirty_init(d); + bch_flash_dev_request_init(d); + err = add_disk(d->disk); + if (err) + goto err; + + err = kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"); + if (err) + goto err; + + bcache_device_link(d, c, "volume"); + + if (bch_has_feature_obso_large_bucket(&c->cache->sb)) { + pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n"); + pr_err("Please update to the latest bcache-tools to create the cache device\n"); + set_disk_ro(d->disk, 1); + } + + return 0; +err: + kobject_put(&d->kobj); +err_ret: + return err; +} + +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; + + if (!test_bit(CACHE_SET_RUNNING, &c->flags)) + return -EPERM; + + u = uuid_find_empty(c); + if (!u) { + pr_err("Can't create volume, no room for UUID\n"); + return -EINVAL; + } + + get_random_bytes(u->uuid, 16); + memset(u->label, 0, 32); + u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds()); + + SET_UUID_FLASH_ONLY(u, 1); + u->sectors = size >> 9; + + bch_uuid_write(c); + + return flash_dev_run(c, u); +} + +bool bch_cached_dev_error(struct cached_dev *dc) +{ + if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags)) + return false; + + dc->io_disable = true; + /* make others know io_disable is true earlier */ + smp_mb(); + + pr_err("stop %s: too many IO errors on backing device %pg\n", + dc->disk.disk->disk_name, dc->bdev); + + bcache_device_stop(&dc->disk); + return true; +} + +/* Cache set */ + +__printf(2, 3) +bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + if (c->on_error != ON_ERROR_PANIC && + test_bit(CACHE_SET_STOPPING, &c->flags)) + return false; + + if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) + pr_info("CACHE_SET_IO_DISABLE already set\n"); + + /* + * XXX: we can be called from atomic context + * acquire_console_sem(); + */ + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + pr_err("error on %pU: %pV, disabling caching\n", + c->set_uuid, &vaf); + + va_end(args); + + if (c->on_error == ON_ERROR_PANIC) + panic("panic forced after error\n"); + + bch_cache_set_unregister(c); + return true; +} + +/* When c->kobj released */ +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; + + debugfs_remove(c->debug); + + bch_open_buckets_free(c); + bch_btree_cache_free(c); + bch_journal_free(c); + + mutex_lock(&bch_register_lock); + bch_bset_sort_state_free(&c->sort); + free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb))); + + ca = c->cache; + if (ca) { + ca->set = NULL; + c->cache = NULL; + kobject_put(&ca->kobj); + } + + + if (c->moving_gc_wq) + destroy_workqueue(c->moving_gc_wq); + bioset_exit(&c->bio_split); + mempool_exit(&c->fill_iter); + mempool_exit(&c->bio_meta); + mempool_exit(&c->search); + kfree(c->devices); + + list_del(&c->list); + mutex_unlock(&bch_register_lock); + + pr_info("Cache set %pU unregistered\n", c->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 cache *ca = c->cache; + struct btree *b; + + bch_cache_accounting_destroy(&c->accounting); + + kobject_put(&c->internal); + kobject_del(&c->kobj); + + if (!IS_ERR_OR_NULL(c->gc_thread)) + kthread_stop(c->gc_thread); + + if (!IS_ERR(c->root)) + list_add(&c->root->list, &c->btree_cache); + + /* + * Avoid flushing cached nodes if cache set is retiring + * due to too many I/O errors detected. + */ + if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags)) + list_for_each_entry(b, &c->btree_cache, list) { + mutex_lock(&b->write_lock); + if (btree_node_dirty(b)) + __bch_btree_node_write(b, NULL); + mutex_unlock(&b->write_lock); + } + + if (ca->alloc_thread) + kthread_stop(ca->alloc_thread); + + if (c->journal.cur) { + cancel_delayed_work_sync(&c->journal.work); + /* flush last journal entry if needed */ + c->journal.work.work.func(&c->journal.work.work); + } + + closure_return(cl); +} + +/* + * This function is only called when CACHE_SET_IO_DISABLE is set, which means + * cache set is unregistering due to too many I/O errors. In this condition, + * the bcache device might be stopped, it depends on stop_when_cache_set_failed + * value and whether the broken cache has dirty data: + * + * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device + * BCH_CACHED_STOP_AUTO 0 NO + * BCH_CACHED_STOP_AUTO 1 YES + * BCH_CACHED_DEV_STOP_ALWAYS 0 YES + * BCH_CACHED_DEV_STOP_ALWAYS 1 YES + * + * The expected behavior is, if stop_when_cache_set_failed is configured to + * "auto" via sysfs interface, the bcache device will not be stopped if the + * backing device is clean on the broken cache device. + */ +static void conditional_stop_bcache_device(struct cache_set *c, + struct bcache_device *d, + struct cached_dev *dc) +{ + if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) { + pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n", + d->disk->disk_name, c->set_uuid); + bcache_device_stop(d); + } else if (atomic_read(&dc->has_dirty)) { + /* + * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO + * and dc->has_dirty == 1 + */ + pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n", + d->disk->disk_name); + /* + * There might be a small time gap that cache set is + * released but bcache device is not. Inside this time + * gap, regular I/O requests will directly go into + * backing device as no cache set attached to. This + * behavior may also introduce potential inconsistence + * data in writeback mode while cache is dirty. + * Therefore before calling bcache_device_stop() due + * to a broken cache device, dc->io_disable should be + * explicitly set to true. + */ + dc->io_disable = true; + /* make others know io_disable is true earlier */ + smp_mb(); + bcache_device_stop(d); + } else { + /* + * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO + * and dc->has_dirty == 0 + */ + pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n", + d->disk->disk_name); + } +} + +static void __cache_set_unregister(struct closure *cl) +{ + struct cache_set *c = container_of(cl, struct cache_set, caching); + struct cached_dev *dc; + struct bcache_device *d; + size_t i; + + mutex_lock(&bch_register_lock); + + for (i = 0; i < c->devices_max_used; i++) { + d = c->devices[i]; + if (!d) + continue; + + if (!UUID_FLASH_ONLY(&c->uuids[i]) && + test_bit(CACHE_SET_UNREGISTERING, &c->flags)) { + dc = container_of(d, struct cached_dev, disk); + bch_cached_dev_detach(dc); + if (test_bit(CACHE_SET_IO_DISABLE, &c->flags)) + conditional_stop_bcache_device(c, d, dc); + } else { + bcache_device_stop(d); + } + } + + 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_fn set to __cache_set_unregister() */ + 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_meta_bucket_pages(gfp, sb) \ + ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb)))) + +struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) +{ + int iter_size; + struct cache *ca = container_of(sb, struct cache, sb); + 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->set_uuid, sb->set_uuid, 16); + + c->cache = ca; + c->cache->set = c; + c->bucket_bits = ilog2(sb->bucket_size); + c->block_bits = ilog2(sb->block_size); + c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry); + c->devices_max_used = 0; + atomic_set(&c->attached_dev_nr, 0); + c->btree_pages = meta_bucket_pages(sb); + if (c->btree_pages > BTREE_MAX_PAGES) + c->btree_pages = max_t(int, c->btree_pages / 4, + BTREE_MAX_PAGES); + + sema_init(&c->sb_write_mutex, 1); + mutex_init(&c->bucket_lock); + init_waitqueue_head(&c->btree_cache_wait); + spin_lock_init(&c->btree_cannibalize_lock); + init_waitqueue_head(&c->bucket_wait); + init_waitqueue_head(&c->gc_wait); + sema_init(&c->uuid_write_mutex, 1); + + spin_lock_init(&c->btree_gc_time.lock); + spin_lock_init(&c->btree_split_time.lock); + 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); + + iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) * + sizeof(struct btree_iter_set); + + c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL); + if (!c->devices) + goto err; + + if (mempool_init_slab_pool(&c->search, 32, bch_search_cache)) + goto err; + + if (mempool_init_kmalloc_pool(&c->bio_meta, 2, + sizeof(struct bbio) + + sizeof(struct bio_vec) * meta_bucket_pages(sb))) + goto err; + + if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size)) + goto err; + + if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), + BIOSET_NEED_RESCUER)) + goto err; + + c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb); + if (!c->uuids) + goto err; + + c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0); + if (!c->moving_gc_wq) + goto err; + + if (bch_journal_alloc(c)) + goto err; + + if (bch_btree_cache_alloc(c)) + goto err; + + if (bch_open_buckets_alloc(c)) + goto err; + + if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages))) + goto err; + + c->congested_read_threshold_us = 2000; + c->congested_write_threshold_us = 20000; + c->error_limit = DEFAULT_IO_ERROR_LIMIT; + c->idle_max_writeback_rate_enabled = 1; + WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); + + return c; +err: + bch_cache_set_unregister(c); + return NULL; +} + +static int run_cache_set(struct cache_set *c) +{ + const char *err = "cannot allocate memory"; + struct cached_dev *dc, *t; + struct cache *ca = c->cache; + struct closure cl; + LIST_HEAD(journal); + struct journal_replay *l; + + closure_init_stack(&cl); + + c->nbuckets = ca->sb.nbuckets; + set_gc_sectors(c); + + if (CACHE_SYNC(&c->cache->sb)) { + struct bkey *k; + struct jset *j; + + err = "cannot allocate memory for journal"; + if (bch_journal_read(c, &journal)) + goto err; + + pr_debug("btree_journal_read() done\n"); + + 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"; + if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev])) + goto err; + + /* + * 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_btree_ptr_invalid(c, k)) + goto err; + + err = "error reading btree root"; + c->root = bch_btree_node_get(c, NULL, k, + j->btree_level, + true, NULL); + if (IS_ERR(c->root)) + goto err; + + list_del_init(&c->root->list); + rw_unlock(true, c->root); + + err = uuid_read(c, j, &cl); + if (err) + goto err; + + err = "error in recovery"; + if (bch_btree_check(c)) + goto err; + + bch_journal_mark(c, &journal); + bch_initial_gc_finish(c); + pr_debug("btree_check() done\n"); + + /* + * 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); + + err = "error starting allocator thread"; + if (bch_cache_allocator_start(ca)) + goto err; + + /* + * 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); + + err = "bcache: replay journal failed"; + if (bch_journal_replay(c, &journal)) + goto err; + } else { + unsigned int j; + + pr_notice("invalidating existing data\n"); + 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_initial_gc_finish(c); + + err = "error starting allocator thread"; + if (bch_cache_allocator_start(ca)) + goto err; + + mutex_lock(&c->bucket_lock); + bch_prio_write(ca, true); + mutex_unlock(&c->bucket_lock); + + err = "cannot allocate new UUID bucket"; + if (__uuid_write(c)) + goto err; + + err = "cannot allocate new btree root"; + c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL); + if (IS_ERR(c->root)) + goto err; + + mutex_lock(&c->root->write_lock); + bkey_copy_key(&c->root->key, &MAX_KEY); + bch_btree_node_write(c->root, &cl); + mutex_unlock(&c->root->write_lock); + + 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->cache->sb, true); + + bch_journal_next(&c->journal); + bch_journal_meta(c, &cl); + } + + err = "error starting gc thread"; + if (bch_gc_thread_start(c)) + goto err; + + closure_sync(&cl); + c->cache->sb.last_mount = (u32)ktime_get_real_seconds(); + bcache_write_super(c); + + if (bch_has_feature_obso_large_bucket(&c->cache->sb)) + pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n"); + + list_for_each_entry_safe(dc, t, &uncached_devices, list) + bch_cached_dev_attach(dc, c, NULL); + + flash_devs_run(c); + + bch_journal_space_reserve(&c->journal); + set_bit(CACHE_SET_RUNNING, &c->flags); + return 0; +err: + while (!list_empty(&journal)) { + l = list_first_entry(&journal, struct journal_replay, list); + list_del(&l->list); + kfree(l); + } + + closure_sync(&cl); + + bch_cache_set_error(c, "%s", err); + + return -EIO; +} + +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->set_uuid, ca->sb.set_uuid, 16)) { + if (c->cache) + return "duplicate cache set member"; + + 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->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; + + kobject_get(&ca->kobj); + ca->set = c; + ca->set->cache = ca; + + err = "failed to run cache set"; + if (run_cache_set(c) < 0) + goto err; + + return NULL; +err: + bch_cache_set_unregister(c); + return err; +} + +/* Cache device */ + +/* When ca->kobj released */ +void bch_cache_release(struct kobject *kobj) +{ + struct cache *ca = container_of(kobj, struct cache, kobj); + unsigned int i; + + if (ca->set) { + BUG_ON(ca->set->cache != ca); + ca->set->cache = NULL; + } + + free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb))); + kfree(ca->prio_buckets); + vfree(ca->buckets); + + free_heap(&ca->heap); + free_fifo(&ca->free_inc); + + for (i = 0; i < RESERVE_NR; i++) + free_fifo(&ca->free[i]); + + if (ca->sb_disk) + put_page(virt_to_page(ca->sb_disk)); + + if (!IS_ERR_OR_NULL(ca->bdev)) + blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); + + kfree(ca); + module_put(THIS_MODULE); +} + +static int cache_alloc(struct cache *ca) +{ + size_t free; + size_t btree_buckets; + struct bucket *b; + int ret = -ENOMEM; + const char *err = NULL; + + __module_get(THIS_MODULE); + kobject_init(&ca->kobj, &bch_cache_ktype); + + bio_init(&ca->journal.bio, NULL, ca->journal.bio.bi_inline_vecs, 8, 0); + + /* + * when ca->sb.njournal_buckets is not zero, journal exists, + * and in bch_journal_replay(), tree node may split, + * so bucket of RESERVE_BTREE type is needed, + * the worst situation is all journal buckets are valid journal, + * and all the keys need to replay, + * so the number of RESERVE_BTREE type buckets should be as much + * as journal buckets + */ + btree_buckets = ca->sb.njournal_buckets ?: 8; + free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; + if (!free) { + ret = -EPERM; + err = "ca->sb.nbuckets is too small"; + goto err_free; + } + + if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, + GFP_KERNEL)) { + err = "ca->free[RESERVE_BTREE] alloc failed"; + goto err_btree_alloc; + } + + if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), + GFP_KERNEL)) { + err = "ca->free[RESERVE_PRIO] alloc failed"; + goto err_prio_alloc; + } + + if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) { + err = "ca->free[RESERVE_MOVINGGC] alloc failed"; + goto err_movinggc_alloc; + } + + if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) { + err = "ca->free[RESERVE_NONE] alloc failed"; + goto err_none_alloc; + } + + if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) { + err = "ca->free_inc alloc failed"; + goto err_free_inc_alloc; + } + + if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) { + err = "ca->heap alloc failed"; + goto err_heap_alloc; + } + + ca->buckets = vzalloc(array_size(sizeof(struct bucket), + ca->sb.nbuckets)); + if (!ca->buckets) { + err = "ca->buckets alloc failed"; + goto err_buckets_alloc; + } + + ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t), + prio_buckets(ca), 2), + GFP_KERNEL); + if (!ca->prio_buckets) { + err = "ca->prio_buckets alloc failed"; + goto err_prio_buckets_alloc; + } + + ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb); + if (!ca->disk_buckets) { + err = "ca->disk_buckets alloc failed"; + goto err_disk_buckets_alloc; + } + + ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); + + for_each_bucket(b, ca) + atomic_set(&b->pin, 0); + return 0; + +err_disk_buckets_alloc: + kfree(ca->prio_buckets); +err_prio_buckets_alloc: + vfree(ca->buckets); +err_buckets_alloc: + free_heap(&ca->heap); +err_heap_alloc: + free_fifo(&ca->free_inc); +err_free_inc_alloc: + free_fifo(&ca->free[RESERVE_NONE]); +err_none_alloc: + free_fifo(&ca->free[RESERVE_MOVINGGC]); +err_movinggc_alloc: + free_fifo(&ca->free[RESERVE_PRIO]); +err_prio_alloc: + free_fifo(&ca->free[RESERVE_BTREE]); +err_btree_alloc: +err_free: + module_put(THIS_MODULE); + if (err) + pr_notice("error %pg: %s\n", ca->bdev, err); + return ret; +} + +static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk, + struct block_device *bdev, struct cache *ca) +{ + const char *err = NULL; /* must be set for any error case */ + int ret = 0; + + memcpy(&ca->sb, sb, sizeof(struct cache_sb)); + ca->bdev = bdev; + ca->bdev->bd_holder = ca; + ca->sb_disk = sb_disk; + + if (bdev_max_discard_sectors((bdev))) + ca->discard = CACHE_DISCARD(&ca->sb); + + ret = cache_alloc(ca); + if (ret != 0) { + /* + * If we failed here, it means ca->kobj is not initialized yet, + * kobject_put() won't be called and there is no chance to + * call blkdev_put() to bdev in bch_cache_release(). So we + * explicitly call blkdev_put() here. + */ + blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); + if (ret == -ENOMEM) + err = "cache_alloc(): -ENOMEM"; + else if (ret == -EPERM) + err = "cache_alloc(): cache device is too small"; + else + err = "cache_alloc(): unknown error"; + goto err; + } + + if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) { + err = "error calling kobject_add"; + ret = -ENOMEM; + goto out; + } + + mutex_lock(&bch_register_lock); + err = register_cache_set(ca); + mutex_unlock(&bch_register_lock); + + if (err) { + ret = -ENODEV; + goto out; + } + + pr_info("registered cache device %pg\n", ca->bdev); + +out: + kobject_put(&ca->kobj); + +err: + if (err) + pr_notice("error %pg: %s\n", ca->bdev, err); + + return ret; +} + +/* Global interfaces/init */ + +static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, + const char *buffer, size_t size); +static ssize_t bch_pending_bdevs_cleanup(struct kobject *k, + struct kobj_attribute *attr, + const char *buffer, size_t size); + +kobj_attribute_write(register, register_bcache); +kobj_attribute_write(register_quiet, register_bcache); +kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup); + +static bool bch_is_open_backing(dev_t dev) +{ + struct cache_set *c, *tc; + struct cached_dev *dc, *t; + + list_for_each_entry_safe(c, tc, &bch_cache_sets, list) + list_for_each_entry_safe(dc, t, &c->cached_devs, list) + if (dc->bdev->bd_dev == dev) + return true; + list_for_each_entry_safe(dc, t, &uncached_devices, list) + if (dc->bdev->bd_dev == dev) + return true; + return false; +} + +static bool bch_is_open_cache(dev_t dev) +{ + struct cache_set *c, *tc; + + list_for_each_entry_safe(c, tc, &bch_cache_sets, list) { + struct cache *ca = c->cache; + + if (ca->bdev->bd_dev == dev) + return true; + } + + return false; +} + +static bool bch_is_open(dev_t dev) +{ + return bch_is_open_cache(dev) || bch_is_open_backing(dev); +} + +struct async_reg_args { + struct delayed_work reg_work; + char *path; + struct cache_sb *sb; + struct cache_sb_disk *sb_disk; + struct block_device *bdev; +}; + +static void register_bdev_worker(struct work_struct *work) +{ + int fail = false; + struct async_reg_args *args = + container_of(work, struct async_reg_args, reg_work.work); + struct cached_dev *dc; + + dc = kzalloc(sizeof(*dc), GFP_KERNEL); + if (!dc) { + fail = true; + put_page(virt_to_page(args->sb_disk)); + blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); + goto out; + } + + mutex_lock(&bch_register_lock); + if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0) + fail = true; + mutex_unlock(&bch_register_lock); + +out: + if (fail) + pr_info("error %s: fail to register backing device\n", + args->path); + kfree(args->sb); + kfree(args->path); + kfree(args); + module_put(THIS_MODULE); +} + +static void register_cache_worker(struct work_struct *work) +{ + int fail = false; + struct async_reg_args *args = + container_of(work, struct async_reg_args, reg_work.work); + struct cache *ca; + + ca = kzalloc(sizeof(*ca), GFP_KERNEL); + if (!ca) { + fail = true; + put_page(virt_to_page(args->sb_disk)); + blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); + goto out; + } + + /* blkdev_put() will be called in bch_cache_release() */ + if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0) + fail = true; + +out: + if (fail) + pr_info("error %s: fail to register cache device\n", + args->path); + kfree(args->sb); + kfree(args->path); + kfree(args); + module_put(THIS_MODULE); +} + +static void register_device_async(struct async_reg_args *args) +{ + if (SB_IS_BDEV(args->sb)) + INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker); + else + INIT_DELAYED_WORK(&args->reg_work, register_cache_worker); + + /* 10 jiffies is enough for a delay */ + queue_delayed_work(system_wq, &args->reg_work, 10); +} + +static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, + const char *buffer, size_t size) +{ + const char *err; + char *path = NULL; + struct cache_sb *sb; + struct cache_sb_disk *sb_disk; + struct block_device *bdev; + ssize_t ret; + bool async_registration = false; + +#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION + async_registration = true; +#endif + + ret = -EBUSY; + err = "failed to reference bcache module"; + if (!try_module_get(THIS_MODULE)) + goto out; + + /* For latest state of bcache_is_reboot */ + smp_mb(); + err = "bcache is in reboot"; + if (bcache_is_reboot) + goto out_module_put; + + ret = -ENOMEM; + err = "cannot allocate memory"; + path = kstrndup(buffer, size, GFP_KERNEL); + if (!path) + goto out_module_put; + + sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); + if (!sb) + goto out_free_path; + + ret = -EINVAL; + 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)) { + dev_t dev; + + mutex_lock(&bch_register_lock); + if (lookup_bdev(strim(path), &dev) == 0 && + bch_is_open(dev)) + err = "device already registered"; + else + err = "device busy"; + mutex_unlock(&bch_register_lock); + if (attr == &ksysfs_register_quiet) + goto done; + } + goto out_free_sb; + } + + err = "failed to set blocksize"; + if (set_blocksize(bdev, 4096)) + goto out_blkdev_put; + + err = read_super(sb, bdev, &sb_disk); + if (err) + goto out_blkdev_put; + + err = "failed to register device"; + + if (async_registration) { + /* register in asynchronous way */ + struct async_reg_args *args = + kzalloc(sizeof(struct async_reg_args), GFP_KERNEL); + + if (!args) { + ret = -ENOMEM; + err = "cannot allocate memory"; + goto out_put_sb_page; + } + + args->path = path; + args->sb = sb; + args->sb_disk = sb_disk; + args->bdev = bdev; + register_device_async(args); + /* No wait and returns to user space */ + goto async_done; + } + + if (SB_IS_BDEV(sb)) { + struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); + + if (!dc) { + ret = -ENOMEM; + err = "cannot allocate memory"; + goto out_put_sb_page; + } + + mutex_lock(&bch_register_lock); + ret = register_bdev(sb, sb_disk, bdev, dc); + mutex_unlock(&bch_register_lock); + /* blkdev_put() will be called in cached_dev_free() */ + if (ret < 0) + goto out_free_sb; + } else { + struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); + + if (!ca) { + ret = -ENOMEM; + err = "cannot allocate memory"; + goto out_put_sb_page; + } + + /* blkdev_put() will be called in bch_cache_release() */ + ret = register_cache(sb, sb_disk, bdev, ca); + if (ret) + goto out_free_sb; + } + +done: + kfree(sb); + kfree(path); + module_put(THIS_MODULE); +async_done: + return size; + +out_put_sb_page: + put_page(virt_to_page(sb_disk)); +out_blkdev_put: + blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); +out_free_sb: + kfree(sb); +out_free_path: + kfree(path); + path = NULL; +out_module_put: + module_put(THIS_MODULE); +out: + pr_info("error %s: %s\n", path?path:"", err); + return ret; +} + + +struct pdev { + struct list_head list; + struct cached_dev *dc; +}; + +static ssize_t bch_pending_bdevs_cleanup(struct kobject *k, + struct kobj_attribute *attr, + const char *buffer, + size_t size) +{ + LIST_HEAD(pending_devs); + ssize_t ret = size; + struct cached_dev *dc, *tdc; + struct pdev *pdev, *tpdev; + struct cache_set *c, *tc; + + mutex_lock(&bch_register_lock); + list_for_each_entry_safe(dc, tdc, &uncached_devices, list) { + pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL); + if (!pdev) + break; + pdev->dc = dc; + list_add(&pdev->list, &pending_devs); + } + + list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) { + char *pdev_set_uuid = pdev->dc->sb.set_uuid; + list_for_each_entry_safe(c, tc, &bch_cache_sets, list) { + char *set_uuid = c->set_uuid; + + if (!memcmp(pdev_set_uuid, set_uuid, 16)) { + list_del(&pdev->list); + kfree(pdev); + break; + } + } + } + mutex_unlock(&bch_register_lock); + + list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) { + pr_info("delete pdev %p\n", pdev); + list_del(&pdev->list); + bcache_device_stop(&pdev->dc->disk); + kfree(pdev); + } + + return ret; +} + +static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x) +{ + if (bcache_is_reboot) + return NOTIFY_DONE; + + 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 (bcache_is_reboot) + goto out; + + /* New registration is rejected since now */ + bcache_is_reboot = true; + /* + * Make registering caller (if there is) on other CPU + * core know bcache_is_reboot set to true earlier + */ + smp_mb(); + + if (list_empty(&bch_cache_sets) && + list_empty(&uncached_devices)) + goto out; + + mutex_unlock(&bch_register_lock); + + pr_info("Stopping all devices:\n"); + + /* + * The reason bch_register_lock is not held to call + * bch_cache_set_stop() and bcache_device_stop() is to + * avoid potential deadlock during reboot, because cache + * set or bcache device stopping process will acquire + * bch_register_lock too. + * + * We are safe here because bcache_is_reboot sets to + * true already, register_bcache() will reject new + * registration now. bcache_is_reboot also makes sure + * bcache_reboot() won't be re-entered on by other thread, + * so there is no race in following list iteration by + * list_for_each_entry_safe(). + */ + 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); + + + /* + * Give an early chance for other kthreads and + * kworkers to stop themselves + */ + schedule(); + + /* What's a condition variable? */ + while (1) { + long timeout = start + 10 * HZ - jiffies; + + mutex_lock(&bch_register_lock); + 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); + } + + finish_wait(&unregister_wait, &wait); + + if (stopped) + pr_info("All devices stopped\n"); + else + pr_notice("Timeout waiting for devices to be closed\n"); +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_request_exit(); + if (bcache_kobj) + kobject_put(bcache_kobj); + if (bcache_wq) + destroy_workqueue(bcache_wq); + if (bch_journal_wq) + destroy_workqueue(bch_journal_wq); + if (bch_flush_wq) + destroy_workqueue(bch_flush_wq); + bch_btree_exit(); + + if (bcache_major) + unregister_blkdev(bcache_major, "bcache"); + unregister_reboot_notifier(&reboot); + mutex_destroy(&bch_register_lock); +} + +/* Check and fixup module parameters */ +static void check_module_parameters(void) +{ + if (bch_cutoff_writeback_sync == 0) + bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC; + else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) { + pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n", + bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX); + bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX; + } + + if (bch_cutoff_writeback == 0) + bch_cutoff_writeback = CUTOFF_WRITEBACK; + else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) { + pr_warn("set bch_cutoff_writeback (%u) to max value %u\n", + bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX); + bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX; + } + + if (bch_cutoff_writeback > bch_cutoff_writeback_sync) { + pr_warn("set bch_cutoff_writeback (%u) to %u\n", + bch_cutoff_writeback, bch_cutoff_writeback_sync); + bch_cutoff_writeback = bch_cutoff_writeback_sync; + } +} + +static int __init bcache_init(void) +{ + static const struct attribute *files[] = { + &ksysfs_register.attr, + &ksysfs_register_quiet.attr, + &ksysfs_pendings_cleanup.attr, + NULL + }; + + check_module_parameters(); + + mutex_init(&bch_register_lock); + init_waitqueue_head(&unregister_wait); + register_reboot_notifier(&reboot); + + bcache_major = register_blkdev(0, "bcache"); + if (bcache_major < 0) { + unregister_reboot_notifier(&reboot); + mutex_destroy(&bch_register_lock); + return bcache_major; + } + + if (bch_btree_init()) + goto err; + + bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); + if (!bcache_wq) + goto err; + + /* + * Let's not make this `WQ_MEM_RECLAIM` for the following reasons: + * + * 1. It used `system_wq` before which also does no memory reclaim. + * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and + * reduced throughput can be observed. + * + * We still want to user our own queue to not congest the `system_wq`. + */ + bch_flush_wq = alloc_workqueue("bch_flush", 0, 0); + if (!bch_flush_wq) + goto err; + + bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); + if (!bch_journal_wq) + goto err; + + bcache_kobj = kobject_create_and_add("bcache", fs_kobj); + if (!bcache_kobj) + goto err; + + if (bch_request_init() || + sysfs_create_files(bcache_kobj, files)) + goto err; + + bch_debug_init(); + closure_debug_init(); + + bcache_is_reboot = false; + + return 0; +err: + bcache_exit(); + return -ENOMEM; +} + +/* + * Module hooks + */ +module_exit(bcache_exit); +module_init(bcache_init); + +module_param(bch_cutoff_writeback, uint, 0); +MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback"); + +module_param(bch_cutoff_writeback_sync, uint, 0); +MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback"); + +MODULE_DESCRIPTION("Bcache: a Linux block layer cache"); +MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>"); +MODULE_LICENSE("GPL"); |