| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Kent Overstreet | 10169 | 80.90% | 51 | 35.42% |
| Coly Li | 938 | 7.46% | 26 | 18.06% |
| Gabriel de Perthuis | 304 | 2.42% | 4 | 2.78% |
| Dongbo Cao | 280 | 2.23% | 3 | 2.08% |
| tang.junhui | 143 | 1.14% | 8 | 5.56% |
| Slava Pestov | 120 | 0.95% | 7 | 4.86% |
| Eric Wheeler | 106 | 0.84% | 5 | 3.47% |
| Michael Christie | 62 | 0.49% | 1 | 0.69% |
| Florian Schmaus | 60 | 0.48% | 3 | 2.08% |
| Michael Lyle | 53 | 0.42% | 1 | 0.69% |
| Wang Sheng-Hui | 43 | 0.34% | 2 | 1.39% |
| Guoju Fang | 33 | 0.26% | 1 | 0.69% |
| Arnd Bergmann | 24 | 0.19% | 1 | 0.69% |
| Christoph Hellwig | 23 | 0.18% | 4 | 2.78% |
| Bart Van Assche | 22 | 0.18% | 2 | 1.39% |
| Nicholas Swenson | 21 | 0.17% | 2 | 1.39% |
| Liang Chen | 18 | 0.14% | 1 | 0.69% |
| Al Viro | 18 | 0.14% | 1 | 0.69% |
| Zheng Liu | 18 | 0.14% | 2 | 1.39% |
| Jan Kara | 17 | 0.14% | 2 | 1.39% |
| Ming Lei | 17 | 0.14% | 1 | 0.69% |
| Kees Cook | 13 | 0.10% | 3 | 2.08% |
| Jianjian Huo | 12 | 0.10% | 1 | 0.69% |
| Lei Ming | 12 | 0.10% | 1 | 0.69% |
| Bhaktipriya Shridhar | 10 | 0.08% | 1 | 0.69% |
| Mike Snitzer | 10 | 0.08% | 1 | 0.69% |
| Jens Axboe | 9 | 0.07% | 3 | 2.08% |
| Neil Brown | 8 | 0.06% | 2 | 1.39% |
| Michal Hocko | 2 | 0.02% | 1 | 0.69% |
| Elena Reshetova | 2 | 0.02% | 1 | 0.69% |
| Pekka J Enberg | 2 | 0.02% | 1 | 0.69% |
| Emil Goode | 1 | 0.01% | 1 | 0.69% |
| Total | 12570 | 144 |
// 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 <linux/blkdev.h> #include <linux/buffer_head.h> #include <linux/debugfs.h> #include <linux/genhd.h> #include <linux/idr.h> #include <linux/kthread.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; 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_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 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 int 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->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 = (u32)ktime_get_real_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) { struct cached_dev *dc = bio->bi_private; /* XXX: error checking */ closure_put(&dc->sb_write); } static void __write_super(struct cache_sb *sb, struct bio *bio) { struct cache_sb *out = page_address(bio_first_page_all(bio)); unsigned int i; bio->bi_iter.bi_sector = SB_SECTOR; bio->bi_iter.bi_size = SB_SIZE; bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META); 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(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_reset(bio); bio_set_dev(bio, dc->bdev); 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, 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; unsigned int i; down(&c->sb_write_mutex); closure_init(cl, &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_set_dev(bio, ca->bdev); bio->bi_end_io = write_super_endio; bio->bi_private = ca; closure_get(cl); __write_super(&ca->sb, 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, int op, unsigned long op_flags, 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 = REQ_SYNC | REQ_META | op_flags; bio->bi_iter.bi_size = KEY_SIZE(k) << 9; bio->bi_end_io = uuid_endio; bio->bi_private = cl; bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); bch_bio_map(bio, c->uuids); bch_submit_bbio(bio, c, k, i); if (op != REQ_OP_WRITE) break; } bch_extent_to_text(buf, sizeof(buf), k); pr_debug("%s UUIDs at %s", op == 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", 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, 0, 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; closure_init_stack(&cl); lockdep_assert_held(&bch_register_lock); if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true)) return 1; SET_KEY_SIZE(&k.key, c->sb.bucket_size); uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl); closure_sync(&cl); /* Only one bucket used for uuid write */ ca = PTR_CACHE(c, &k.key, 0); 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, int op, unsigned long op_flags) { 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 = bucket_bytes(ca); bio->bi_end_io = prio_endio; bio->bi_private = ca; bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags); bch_bio_map(bio, ca->disk_buckets); closure_bio_submit(ca->set, bio, &ca->prio); closure_sync(cl); } 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); 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)); 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, bucket_bytes(ca) - 8); bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true); BUG_ON(bucket == -1); mutex_unlock(&ca->set->bucket_lock); prio_io(ca, bucket, REQ_OP_WRITE, 0); 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]; } } 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 int 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, REQ_OP_READ, 0); if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8)) pr_warn("bad csum reading priorities"); if (p->magic != pset_magic(&ca->sb)) pr_warn("bad magic reading priorities"); bucket = p->next_bucket; d = p->data; } b->prio = le16_to_cpu(d->prio); b->gen = b->last_gc = 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 (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_ops = { .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_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)) { unsigned int 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 int 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"); 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) { 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) { ida_simple_remove(&bcache_device_idx, first_minor_to_idx(d->disk->first_minor)); put_disk(d->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 request_queue *q; const size_t max_stripes = min_t(size_t, INT_MAX, SIZE_MAX / sizeof(atomic_t)); size_t n; int idx; if (!d->stripe_size) d->stripe_size = 1 << 31; d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size); if (!d->nr_stripes || d->nr_stripes > max_stripes) { pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)", (unsigned int)d->nr_stripes); return -ENOMEM; } 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) return -ENOMEM; idx = ida_simple_get(&bcache_device_idx, 0, BCACHE_DEVICE_IDX_MAX, GFP_KERNEL); if (idx < 0) return idx; if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio), BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER)) goto err; d->disk = alloc_disk(BCACHE_MINORS); if (!d->disk) goto err; 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->fops = &bcache_ops; d->disk->private_data = d; q = blk_alloc_queue(GFP_KERNEL); if (!q) return -ENOMEM; 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; 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; blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue); blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue); blk_queue_write_cache(q, true, true); return 0; err: ida_simple_remove(&bcache_device_idx, idx); 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_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("%s: device offline for %d seconds", dc->backing_dev_name, BACKING_DEV_OFFLINE_TIMEOUT); pr_err("%s: disable I/O request due to backing " "device offline", 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; } void bch_cached_dev_run(struct cached_dev *dc) { struct bcache_device *d = &dc->disk; char buf[SB_LABEL_SIZE + 1]; char *env[] = { "DRIVER=bcache", kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid), NULL, NULL, }; memcpy(buf, dc->sb.label, SB_LABEL_SIZE); buf[SB_LABEL_SIZE] = '\0'; env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); if (atomic_xchg(&dc->running, 1)) { kfree(env[1]); kfree(env[2]); 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); /* * 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); kfree(env[1]); kfree(env[2]); 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"); 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"); } } /* * 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"); 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 closure cl; closure_init_stack(&cl); BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); BUG_ON(refcount_read(&dc->count)); mutex_lock(&bch_register_lock); 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; } memset(&dc->sb.set_uuid, 0, 16); SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); bch_write_bdev_super(dc, &cl); closure_sync(&cl); calc_cached_dev_sectors(dc->disk.c); bcache_device_detach(&dc->disk); list_move(&dc->list, &uncached_devices); 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 %s", dc->backing_dev_name); /* 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; if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) || (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))) return -ENOENT; if (dc->disk.c) { pr_err("Can't attach %s: already attached", dc->backing_dev_name); return -EINVAL; } if (test_bit(CACHE_SET_STOPPING, &c->flags)) { pr_err("Can't attach %s: shutting down", dc->backing_dev_name); 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", dc->backing_dev_name); 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 %s but duplicate UUID already attached", dc->backing_dev_name); 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 %s in set", dc->backing_dev_name); return -ENOENT; } u = uuid_find_empty(c); if (!u) { pr_err("Not caching %s, no room for UUID", dc->backing_dev_name); 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); /* * 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); 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); bch_cached_dev_run(dc); bcache_device_link(&dc->disk, c, "bdev"); atomic_inc(&c->attached_dev_nr); /* Allow the writeback thread to proceed */ up_write(&dc->writeback_lock); pr_info("Caching %s as %s on set %pU", dc->backing_dev_name, 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); mutex_lock(&bch_register_lock); 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 (dc->writeback_write_wq) destroy_workqueue(dc->writeback_write_wq); if (!IS_ERR_OR_NULL(dc->status_update_thread)) kthread_stop(dc->status_update_thread); 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)) 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, dc->bdev->bd_part->nr_sects - dc->sb.data_offset); if (ret) return ret; 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); 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 void register_bdev(struct cache_sb *sb, struct page *sb_page, struct block_device *bdev, struct cached_dev *dc) { const char *err = "cannot allocate memory"; struct cache_set *c; bdevname(bdev, dc->backing_dev_name); 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_inline_vecs, 1); bio_first_bvec_all(&dc->sb_bio)->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", dc->backing_dev_name); 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) bch_cached_dev_run(dc); return; err: pr_notice("error %s: %s", dc->backing_dev_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); mutex_lock(&bch_register_lock); atomic_long_sub(bcache_dev_sectors_dirty(d), &d->c->flash_dev_dirty_sectors); 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) { 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), u->sectors)) goto err; bcache_device_attach(d, c, u - c->uuids); bch_sectors_dirty_init(d); 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; 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"); 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) { struct cache_set *c; 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 %s\n", dc->disk.disk->disk_name, dc->backing_dev_name); /* * If the cached device is still attached to a cache set, * even dc->io_disable is true and no more I/O requests * accepted, cache device internal I/O (writeback scan or * garbage collection) may still prevent bcache device from * being stopped. So here CACHE_SET_IO_DISABLE should be * set to c->flags too, to make the internal I/O to cache * device rejected and stopped immediately. * If c is NULL, that means the bcache device is not attached * to any cache set, then no CACHE_SET_IO_DISABLE bit to set. */ c = dc->disk.c; if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags)) pr_info("CACHE_SET_IO_DISABLE already set"); bcache_device_stop(&dc->disk); return true; } /* Cache set */ __printf(2, 3) bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...) { 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"); /* * XXX: we can be called from atomic context * acquire_console_sem(); */ pr_err("bcache: error on %pU: ", c->sb.set_uuid); va_start(args, fmt); vprintk(fmt, args); va_end(args); pr_err(", disabling caching\n"); if (c->on_error == ON_ERROR_PANIC) panic("panic forced after error\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 int i; 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) { ca->set = NULL; c->cache[ca->sb.nr_this_dev] = NULL; kobject_put(&ca->kobj); } bch_bset_sort_state_free(&c->sort); free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c))); 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); 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 cache *ca; struct btree *b; unsigned int i; bch_cache_accounting_destroy(&c->accounting); kobject_put(&c->internal); kobject_del(&c->kobj); if (c->gc_thread) kthread_stop(c->gc_thread); 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) { mutex_lock(&b->write_lock); if (btree_node_dirty(b)) __bch_btree_node_write(b, NULL); mutex_unlock(&b->write_lock); } for_each_cache(ca, c, i) 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.", d->disk->disk_name, c->sb.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.", 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.", 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_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->devices_max_used = 0; atomic_set(&c->attached_dev_nr, 0); c->btree_pages = bucket_pages(c); 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); 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 = (sb->bucket_size / sb->block_size + 1) * sizeof(struct btree_iter_set); if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) || mempool_init_slab_pool(&c->search, 32, bch_search_cache) || mempool_init_kmalloc_pool(&c->bio_meta, 2, sizeof(struct bbio) + sizeof(struct bio_vec) * bucket_pages(c)) || mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio), BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) || !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) || !(c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0)) || bch_journal_alloc(c) || bch_btree_cache_alloc(c) || bch_open_buckets_alloc(c) || 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; WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags)); 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; struct closure cl; unsigned int i; closure_init_stack(&cl); for_each_cache(ca, c, i) c->nbuckets += ca->sb.nbuckets; set_gc_sectors(c); 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)) 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_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_OR_NULL(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"); /* * 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"; for_each_cache(ca, c, i) 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); bch_journal_replay(c, &journal); } else { pr_notice("invalidating existing data"); for_each_cache(ca, c, i) { unsigned int 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_initial_gc_finish(c); err = "error starting allocator thread"; for_each_cache(ca, c, i) if (bch_cache_allocator_start(ca)) goto err; mutex_lock(&c->bucket_lock); for_each_cache(ca, c, i) bch_prio_write(ca); 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_OR_NULL(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->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->sb.last_mount = (u32)ktime_get_real_seconds(); bcache_write_super(c); list_for_each_entry_safe(dc, t, &uncached_devices, list) bch_cached_dev_attach(dc, c, NULL); flash_devs_run(c); set_bit(CACHE_SET_RUNNING, &c->flags); return; err: closure_sync(&cl); /* XXX: test this, it's broken */ bch_cache_set_error(c, "%s", 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.bucket_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); } kobject_get(&ca->kobj); 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); unsigned int i; if (ca->set) { BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca); ca->set->cache[ca->sb.nr_this_dev] = NULL; } 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->free_inc); for (i = 0; i < RESERVE_NR; i++) free_fifo(&ca->free[i]); if (ca->sb_bio.bi_inline_vecs[0].bv_page) put_page(bio_first_page_all(&ca->sb_bio)); 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, ca->journal.bio.bi_inline_vecs, 8); /* * 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_bucket_pages(GFP_KERNEL, ca); 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 %s: %s", ca->cache_dev_name, err); return ret; } static int register_cache(struct cache_sb *sb, struct page *sb_page, struct block_device *bdev, struct cache *ca) { const char *err = NULL; /* must be set for any error case */ int ret = 0; bdevname(bdev, ca->cache_dev_name); 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_inline_vecs, 1); bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page; get_page(sb_page); if (blk_queue_discard(bdev_get_queue(bdev))) ca->discard = CACHE_DISCARD(&ca->sb); ret = cache_alloc(ca); if (ret != 0) { 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, &part_to_dev(bdev->bd_part)->kobj, "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 %s", ca->cache_dev_name); out: kobject_put(&ca->kobj); err: if (err) pr_notice("error %s: %s", ca->cache_dev_name, err); return ret; } /* Global interfaces/init */ static ssize_t register_bcache(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); static bool bch_is_open_backing(struct block_device *bdev) { 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 == bdev) return true; list_for_each_entry_safe(dc, t, &uncached_devices, list) if (dc->bdev == bdev) return true; return false; } static bool bch_is_open_cache(struct block_device *bdev) { struct cache_set *c, *tc; struct cache *ca; unsigned int i; list_for_each_entry_safe(c, tc, &bch_cache_sets, list) for_each_cache(ca, c, i) if (ca->bdev == bdev) return true; return false; } static bool bch_is_open(struct block_device *bdev) { return bch_is_open_cache(bdev) || bch_is_open_backing(bdev); } 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; path = kstrndup(buffer, size, GFP_KERNEL); if (!path) goto err; sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL); if (!sb) 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)) { bdev = lookup_bdev(strim(path)); mutex_lock(&bch_register_lock); if (!IS_ERR(bdev) && bch_is_open(bdev)) err = "device already registered"; else err = "device busy"; mutex_unlock(&bch_register_lock); if (!IS_ERR(bdev)) bdput(bdev); if (attr == &ksysfs_register_quiet) goto out; } 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; err = "failed to register device"; if (SB_IS_BDEV(sb)) { struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); if (!dc) goto err_close; mutex_lock(&bch_register_lock); register_bdev(sb, sb_page, bdev, dc); mutex_unlock(&bch_register_lock); } else { struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL); if (!ca) goto err_close; if (register_cache(sb, sb_page, bdev, ca) != 0) goto err; } out: if (sb_page) put_page(sb_page); kfree(sb); kfree(path); module_put(THIS_MODULE); return ret; err_close: blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); err: pr_info("error %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_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 (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", 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", 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", 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, 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; } bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0); if (!bcache_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(); 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");
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