| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Kent Overstreet | 8971 | 65.26% | 51 | 19.54% |
| Coly Li | 2470 | 17.97% | 74 | 28.35% |
| Christoph Hellwig | 512 | 3.72% | 28 | 10.73% |
| Dongbo Cao | 272 | 1.98% | 3 | 1.15% |
| Jan Kara | 213 | 1.55% | 4 | 1.53% |
| Gabriel de Perthuis | 147 | 1.07% | 4 | 1.53% |
| tang.junhui | 101 | 0.73% | 9 | 3.45% |
| Eric Wheeler | 90 | 0.65% | 5 | 1.92% |
| Andrea Righi | 90 | 0.65% | 1 | 0.38% |
| Slava Pestov | 82 | 0.60% | 6 | 2.30% |
| Christian Brauner | 79 | 0.57% | 1 | 0.38% |
| Wang Sheng-Hui | 67 | 0.49% | 2 | 0.77% |
| Florian Schmaus | 60 | 0.44% | 3 | 1.15% |
| Joe Perches | 58 | 0.42% | 1 | 0.38% |
| Zhiqiang Liu | 47 | 0.34% | 1 | 0.38% |
| Michael Lyle | 47 | 0.34% | 1 | 0.38% |
| Kai Krakow | 40 | 0.29% | 3 | 1.15% |
| Bart Van Assche | 39 | 0.28% | 4 | 1.53% |
| Guoju Fang | 32 | 0.23% | 2 | 0.77% |
| Luis R. Rodriguez | 32 | 0.23% | 1 | 0.38% |
| Konstantin Khlebnikov | 24 | 0.17% | 1 | 0.38% |
| Arnd Bergmann | 24 | 0.17% | 1 | 0.38% |
| Geliang Tang | 20 | 0.15% | 1 | 0.38% |
| Michael Christie | 18 | 0.13% | 1 | 0.38% |
| Nicholas Swenson | 17 | 0.12% | 1 | 0.38% |
| Lin Feng | 16 | 0.12% | 2 | 0.77% |
| Bhaktipriya Shridhar | 16 | 0.12% | 1 | 0.38% |
| Liang Chen | 15 | 0.11% | 2 | 0.77% |
| Kees Cook | 13 | 0.09% | 3 | 1.15% |
| Zheng Liu | 12 | 0.09% | 2 | 0.77% |
| Tejun Heo | 9 | 0.07% | 1 | 0.38% |
| Al Viro | 9 | 0.07% | 3 | 1.15% |
| Mauricio Faria de Oliveira | 8 | 0.06% | 1 | 0.38% |
| Matthew Mirvish | 6 | 0.04% | 1 | 0.38% |
| Chao Yu | 6 | 0.04% | 1 | 0.38% |
| Ben Blum | 6 | 0.04% | 1 | 0.38% |
| Neil Brown | 6 | 0.04% | 2 | 0.77% |
| Mike Snitzer | 5 | 0.04% | 1 | 0.38% |
| Christophe Jaillet | 5 | 0.04% | 1 | 0.38% |
| Rakesh Pandit | 5 | 0.04% | 1 | 0.38% |
| Jens Axboe | 5 | 0.04% | 2 | 0.77% |
| Lei Ming | 4 | 0.03% | 1 | 0.38% |
| Ingo Molnar | 4 | 0.03% | 1 | 0.38% |
| Daniel Rebelo de Oliveira | 4 | 0.03% | 1 | 0.38% |
| Linus Torvalds (pre-git) | 3 | 0.02% | 2 | 0.77% |
| Davide Libenzi | 3 | 0.02% | 2 | 0.77% |
| Kirill Korotaev | 3 | 0.02% | 1 | 0.38% |
| Arjan van de Ven | 3 | 0.02% | 1 | 0.38% |
| Linus Torvalds | 3 | 0.02% | 2 | 0.77% |
| Martin Schwidefsky | 3 | 0.02% | 2 | 0.77% |
| Oleg Nesterov | 2 | 0.01% | 1 | 0.38% |
| Michal Hocko | 2 | 0.01% | 1 | 0.38% |
| Miloslav Trmač | 2 | 0.01% | 1 | 0.38% |
| Pekka J Enberg | 2 | 0.01% | 1 | 0.38% |
| Ming Lei | 2 | 0.01% | 1 | 0.38% |
| Javier González | 2 | 0.01% | 1 | 0.38% |
| Zheng Wang | 2 | 0.01% | 1 | 0.38% |
| Elena Reshetova | 2 | 0.01% | 1 | 0.38% |
| Emil Goode | 1 | 0.01% | 1 | 0.38% |
| Alexey Dobriyan | 1 | 0.01% | 1 | 0.38% |
| Jean Delvare | 1 | 0.01% | 1 | 0.38% |
| Yi Li | 1 | 0.01% | 1 | 0.38% |
| Colin Ian King | 1 | 0.01% | 1 | 0.38% |
| dingsenjie | 1 | 0.01% | 1 | 0.38% |
| Total | 13746 | 261 |
// 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_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 CLOSURE_CALLBACK(bch_write_bdev_super_unlock) { closure_type(dc, 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 CLOSURE_CALLBACK(bcache_write_super_unlock) { closure_type(c, 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 CLOSURE_CALLBACK(uuid_io_unlock) { closure_type(c, 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 gendisk *disk, blk_mode_t mode) { struct bcache_device *d = 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) { struct bcache_device *d = b->private_data; closure_put(&d->cl); } static int ioctl_dev(struct block_device *b, blk_mode_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_free(&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)); struct queue_limits lim = { .max_hw_sectors = UINT_MAX, .max_sectors = UINT_MAX, .max_segment_size = UINT_MAX, .max_segments = BIO_MAX_VECS, .max_hw_discard_sectors = UINT_MAX, .io_min = block_size, .logical_block_size = block_size, .physical_block_size = block_size, }; uint64_t n; int idx; if (cached_bdev) { d->stripe_size = bdev_io_opt(cached_bdev) >> SECTOR_SHIFT; lim.io_opt = umax(block_size, bdev_io_opt(cached_bdev)); } 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_alloc_max(&bcache_device_idx, BCACHE_DEVICE_IDX_MAX - 1, 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; if (lim.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("bcache%i: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n", idx, lim.logical_block_size, PAGE_SIZE, bdev_logical_block_size(cached_bdev)); /* This also adjusts physical block size/min io size if needed */ lim.logical_block_size = bdev_logical_block_size(cached_bdev); } d->disk = blk_alloc_disk(&lim, NUMA_NO_NODE); if (IS_ERR(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; blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue); blk_queue_write_cache(q, true, true); return 0; out_bioset_exit: bioset_exit(&d->bio_split); out_ida_remove: ida_free(&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 CLOSURE_CALLBACK(cached_dev_free) { closure_type(dc, 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 (dc->bdev_file) fput(dc->bdev_file); wake_up(&unregister_wait); kobject_put(&dc->disk.kobj); } static CLOSURE_CALLBACK(cached_dev_flush) { closure_type(dc, 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); } if (bdev_io_opt(dc->bdev)) 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; 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 file *bdev_file, 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_file = bdev_file; dc->bdev = file_bdev(bdev_file); 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(dc->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 CLOSURE_CALLBACK(flash_dev_free) { closure_type(d, 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 CLOSURE_CALLBACK(flash_dev_flush) { closure_type(d, 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 CLOSURE_CALLBACK(cache_set_free) { closure_type(c, 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 CLOSURE_CALLBACK(cache_set_flush) { closure_type(c, 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 CLOSURE_CALLBACK(__cache_set_unregister) { closure_type(c, 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 = sizeof(struct btree_iter) + ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) * 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 (ca->bdev_file) fput(ca->bdev_file); 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 file *bdev_file, 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_file = bdev_file; ca->bdev = file_bdev(bdev_file); ca->sb_disk = sb_disk; if (bdev_max_discard_sectors(file_bdev(bdev_file))) ca->discard = CACHE_DISCARD(&ca->sb); ret = cache_alloc(ca); if (ret != 0) { 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"; pr_notice("error %pg: %s\n", file_bdev(bdev_file), err); /* * 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 fput() to bdev in bch_cache_release(). So * we explicitly call fput() on the block device here. */ fput(bdev_file); return ret; } if (kobject_add(&ca->kobj, bdev_kobj(file_bdev(bdev_file)), "bcache")) { pr_notice("error %pg: error calling kobject_add\n", file_bdev(bdev_file)); 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", file_bdev(ca->bdev_file)); out: kobject_put(&ca->kobj); 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 file *bdev_file; void *holder; }; 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); mutex_lock(&bch_register_lock); if (register_bdev(args->sb, args->sb_disk, args->bdev_file, args->holder) < 0) fail = true; mutex_unlock(&bch_register_lock); 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); /* blkdev_put() will be called in bch_cache_release() */ if (register_cache(args->sb, args->sb_disk, args->bdev_file, args->holder)) fail = true; 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 void *alloc_holder_object(struct cache_sb *sb) { if (SB_IS_BDEV(sb)) return kzalloc(sizeof(struct cached_dev), GFP_KERNEL); return kzalloc(sizeof(struct cache), GFP_KERNEL); } 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 file *bdev_file, *bdev_file2; void *holder = NULL; ssize_t ret; bool async_registration = false; bool quiet = 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_file = bdev_file_open_by_path(strim(path), BLK_OPEN_READ, NULL, NULL); if (IS_ERR(bdev_file)) goto out_free_sb; err = read_super(sb, file_bdev(bdev_file), &sb_disk); if (err) goto out_blkdev_put; holder = alloc_holder_object(sb); if (!holder) { ret = -ENOMEM; err = "cannot allocate memory"; goto out_put_sb_page; } /* Now reopen in exclusive mode with proper holder */ bdev_file2 = bdev_file_open_by_dev(file_bdev(bdev_file)->bd_dev, BLK_OPEN_READ | BLK_OPEN_WRITE, holder, NULL); fput(bdev_file); bdev_file = bdev_file2; if (IS_ERR(bdev_file)) { ret = PTR_ERR(bdev_file); bdev_file = NULL; if (ret == -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) { quiet = true; ret = size; } } goto out_free_holder; } 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_free_holder; } args->path = path; args->sb = sb; args->sb_disk = sb_disk; args->bdev_file = bdev_file; args->holder = holder; register_device_async(args); /* No wait and returns to user space */ goto async_done; } if (SB_IS_BDEV(sb)) { mutex_lock(&bch_register_lock); ret = register_bdev(sb, sb_disk, bdev_file, holder); mutex_unlock(&bch_register_lock); /* blkdev_put() will be called in cached_dev_free() */ if (ret < 0) goto out_free_sb; } else { /* blkdev_put() will be called in bch_cache_release() */ ret = register_cache(sb, sb_disk, bdev_file, holder); if (ret) goto out_free_sb; } kfree(sb); kfree(path); module_put(THIS_MODULE); async_done: return size; out_free_holder: kfree(holder); out_put_sb_page: put_page(virt_to_page(sb_disk)); out_blkdev_put: if (bdev_file) fput(bdev_file); out_free_sb: kfree(sb); out_free_path: kfree(path); path = NULL; out_module_put: module_put(THIS_MODULE); out: if (!quiet) 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(); 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");
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