/* * bcache setup/teardown code, and some metadata io - read a superblock and * figure out what to do with it. * * Copyright 2010, 2011 Kent Overstreet * Copyright 2012 Google, Inc. */ #include "bcache.h" #include "blockdev.h" #include "alloc.h" #include "btree_cache.h" #include "btree_gc.h" #include "btree_update.h" #include "btree_io.h" #include "chardev.h" #include "checksum.h" #include "clock.h" #include "compress.h" #include "debug.h" #include "error.h" #include "fs.h" #include "fs-gc.h" #include "inode.h" #include "io.h" #include "journal.h" #include "keylist.h" #include "move.h" #include "migrate.h" #include "movinggc.h" #include "notify.h" #include "stats.h" #include "super.h" #include "super-io.h" #include "tier.h" #include "writeback.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Kent Overstreet "); static const uuid_le invalid_uuid = { .b = { 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78, 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99 } }; static struct kset *bcache_kset; struct mutex bch_register_lock; LIST_HEAD(bch_cache_sets); static int bch_chardev_major; static struct class *bch_chardev_class; static struct device *bch_chardev; static DEFINE_IDR(bch_chardev_minor); static DECLARE_WAIT_QUEUE_HEAD(bch_read_only_wait); struct workqueue_struct *bcache_io_wq; struct crypto_shash *bch_sha256; static void bch_cache_stop(struct cache *); static int bch_cache_online(struct cache *); static int bch_congested_fn(void *data, int bdi_bits) { struct backing_dev_info *bdi; struct cache_set *c = data; struct cache *ca; unsigned i; int ret = 0; rcu_read_lock(); if (bdi_bits & (1 << WB_sync_congested)) { /* Reads - check all devices: */ for_each_cache_rcu(ca, c, i) { bdi = blk_get_backing_dev_info(ca->disk_sb.bdev); if (bdi_congested(bdi, bdi_bits)) { ret = 1; break; } } } else { /* Writes only go to tier 0: */ group_for_each_cache_rcu(ca, &c->cache_tiers[0], i) { bdi = blk_get_backing_dev_info(ca->disk_sb.bdev); if (bdi_congested(bdi, bdi_bits)) { ret = 1; break; } } } rcu_read_unlock(); return ret; } /* Cache set RO/RW: */ /* * For startup/shutdown of RW stuff, the dependencies are: * * - foreground writes depend on copygc and tiering (to free up space) * * - copygc and tiering depend on mark and sweep gc (they actually probably * don't because they either reserve ahead of time or don't block if * allocations fail, but allocations can require mark and sweep gc to run * because of generation number wraparound) * * - all of the above depends on the allocator threads * * - allocator depends on the journal (when it rewrites prios and gens) */ static void __bch_cache_set_read_only(struct cache_set *c) { struct cache *ca; unsigned i; c->tiering_pd.rate.rate = UINT_MAX; bch_ratelimit_reset(&c->tiering_pd.rate); bch_tiering_read_stop(c); for_each_cache(ca, c, i) bch_moving_gc_stop(ca); bch_gc_thread_stop(c); bch_btree_flush(c); for_each_cache(ca, c, i) bch_cache_allocator_stop(ca); /* * Write a journal entry after flushing the btree, so we don't end up * replaying everything we just flushed: */ if (test_bit(JOURNAL_STARTED, &c->journal.flags)) { int ret; bch_journal_flush_async(&c->journal, NULL); ret = bch_journal_meta(&c->journal); BUG_ON(ret && !bch_journal_error(&c->journal)); } cancel_delayed_work_sync(&c->journal.write_work); cancel_delayed_work_sync(&c->journal.reclaim_work); } static void bch_writes_disabled(struct percpu_ref *writes) { struct cache_set *c = container_of(writes, struct cache_set, writes); set_bit(CACHE_SET_WRITE_DISABLE_COMPLETE, &c->flags); wake_up(&bch_read_only_wait); } static void bch_cache_set_read_only_work(struct work_struct *work) { struct cache_set *c = container_of(work, struct cache_set, read_only_work); percpu_ref_put(&c->writes); del_timer(&c->foreground_write_wakeup); cancel_delayed_work(&c->pd_controllers_update); c->foreground_write_pd.rate.rate = UINT_MAX; bch_wake_delayed_writes((unsigned long) c); if (!test_bit(CACHE_SET_EMERGENCY_RO, &c->flags)) { /* * If we're not doing an emergency shutdown, we want to wait on * outstanding writes to complete so they don't see spurious * errors due to shutting down the allocator: */ wait_event(bch_read_only_wait, test_bit(CACHE_SET_WRITE_DISABLE_COMPLETE, &c->flags)); __bch_cache_set_read_only(c); if (!bch_journal_error(&c->journal) && !test_bit(CACHE_SET_ERROR, &c->flags)) { mutex_lock(&c->sb_lock); SET_BCH_SB_CLEAN(c->disk_sb, true); bch_write_super(c); mutex_unlock(&c->sb_lock); } } else { /* * If we are doing an emergency shutdown outstanding writes may * hang until we shutdown the allocator so we don't want to wait * on outstanding writes before shutting everything down - but * we do need to wait on them before returning and signalling * that going RO is complete: */ __bch_cache_set_read_only(c); wait_event(bch_read_only_wait, test_bit(CACHE_SET_WRITE_DISABLE_COMPLETE, &c->flags)); } bch_notify_cache_set_read_only(c); trace_bcache_cache_set_read_only_done(c); set_bit(CACHE_SET_RO_COMPLETE, &c->flags); wake_up(&bch_read_only_wait); } bool bch_cache_set_read_only(struct cache_set *c) { if (test_and_set_bit(CACHE_SET_RO, &c->flags)) return false; trace_bcache_cache_set_read_only(c); percpu_ref_get(&c->writes); /* * Block new foreground-end write operations from starting - any new * writes will return -EROFS: * * (This is really blocking new _allocations_, writes to previously * allocated space can still happen until stopping the allocator in * bch_cache_allocator_stop()). */ percpu_ref_kill(&c->writes); queue_work(system_freezable_wq, &c->read_only_work); return true; } bool bch_cache_set_emergency_read_only(struct cache_set *c) { bool ret = !test_and_set_bit(CACHE_SET_EMERGENCY_RO, &c->flags); bch_cache_set_read_only(c); bch_journal_halt(&c->journal); wake_up(&bch_read_only_wait); return ret; } void bch_cache_set_read_only_sync(struct cache_set *c) { /* so we don't race with bch_cache_set_read_write() */ lockdep_assert_held(&bch_register_lock); bch_cache_set_read_only(c); wait_event(bch_read_only_wait, test_bit(CACHE_SET_RO_COMPLETE, &c->flags) && test_bit(CACHE_SET_WRITE_DISABLE_COMPLETE, &c->flags)); } static const char *__bch_cache_set_read_write(struct cache_set *c) { struct cache *ca; const char *err; unsigned i; lockdep_assert_held(&bch_register_lock); err = "error starting allocator thread"; for_each_cache(ca, c, i) if (ca->mi.state == BCH_MEMBER_STATE_ACTIVE && bch_cache_allocator_start(ca)) { percpu_ref_put(&ca->ref); goto err; } err = "error starting btree GC thread"; if (bch_gc_thread_start(c)) goto err; for_each_cache(ca, c, i) { if (ca->mi.state != BCH_MEMBER_STATE_ACTIVE) continue; err = "error starting moving GC thread"; if (bch_moving_gc_thread_start(ca)) { percpu_ref_put(&ca->ref); goto err; } } err = "error starting tiering thread"; if (bch_tiering_read_start(c)) goto err; schedule_delayed_work(&c->pd_controllers_update, 5 * HZ); return NULL; err: __bch_cache_set_read_only(c); return err; } const char *bch_cache_set_read_write(struct cache_set *c) { const char *err; lockdep_assert_held(&bch_register_lock); if (!test_bit(CACHE_SET_RO_COMPLETE, &c->flags)) return NULL; err = __bch_cache_set_read_write(c); if (err) return err; percpu_ref_reinit(&c->writes); clear_bit(CACHE_SET_WRITE_DISABLE_COMPLETE, &c->flags); clear_bit(CACHE_SET_EMERGENCY_RO, &c->flags); clear_bit(CACHE_SET_RO_COMPLETE, &c->flags); clear_bit(CACHE_SET_RO, &c->flags); return NULL; } /* Cache set startup/shutdown: */ static void cache_set_free(struct cache_set *c) { del_timer_sync(&c->foreground_write_wakeup); cancel_delayed_work_sync(&c->pd_controllers_update); cancel_work_sync(&c->read_only_work); cancel_work_sync(&c->bio_submit_work); cancel_work_sync(&c->read_retry_work); bch_cache_set_encryption_free(c); bch_btree_cache_free(c); bch_journal_free(&c->journal); bch_io_clock_exit(&c->io_clock[WRITE]); bch_io_clock_exit(&c->io_clock[READ]); bch_compress_free(c); bdi_destroy(&c->bdi); lg_lock_free(&c->bucket_stats_lock); free_percpu(c->bucket_stats_percpu); mempool_exit(&c->btree_bounce_pool); mempool_exit(&c->bio_bounce_pages); bioset_exit(&c->bio_write); bioset_exit(&c->bio_read_split); bioset_exit(&c->bio_read); bioset_exit(&c->btree_read_bio); mempool_exit(&c->btree_interior_update_pool); mempool_exit(&c->btree_reserve_pool); mempool_exit(&c->fill_iter); mempool_exit(&c->search); percpu_ref_exit(&c->writes); if (c->copygc_wq) destroy_workqueue(c->copygc_wq); if (c->wq) destroy_workqueue(c->wq); kfree_rcu(rcu_dereference_protected(c->members, 1), rcu); /* shutting down */ free_pages((unsigned long) c->disk_sb, c->disk_sb_order); kfree(c); module_put(THIS_MODULE); } /* * should be __cache_set_stop4 - block devices are closed, now we can finally * free it */ void bch_cache_set_release(struct kobject *kobj) { struct cache_set *c = container_of(kobj, struct cache_set, kobj); struct completion *stop_completion = c->stop_completion; bch_notify_cache_set_stopped(c); bch_info(c, "stopped"); cache_set_free(c); if (stop_completion) complete(stop_completion); } /* * All activity on the cache_set should have stopped now - close devices: */ static void __cache_set_stop3(struct closure *cl) { struct cache_set *c = container_of(cl, struct cache_set, cl); struct cache *ca; unsigned i; mutex_lock(&bch_register_lock); for_each_cache(ca, c, i) bch_cache_stop(ca); mutex_unlock(&bch_register_lock); mutex_lock(&bch_register_lock); list_del(&c->list); if (c->minor >= 0) idr_remove(&bch_chardev_minor, c->minor); mutex_unlock(&bch_register_lock); closure_debug_destroy(&c->cl); kobject_put(&c->kobj); } /* * Openers (i.e. block devices) should have exited, shutdown all userspace * interfaces and wait for &c->cl to hit 0 */ static void __cache_set_stop2(struct closure *cl) { struct cache_set *c = container_of(cl, struct cache_set, caching); bch_debug_exit_cache_set(c); if (!IS_ERR_OR_NULL(c->chardev)) device_unregister(c->chardev); if (c->kobj.state_in_sysfs) kobject_del(&c->kobj); bch_cache_accounting_destroy(&c->accounting); kobject_put(&c->time_stats); kobject_put(&c->opts_dir); kobject_put(&c->internal); mutex_lock(&bch_register_lock); bch_cache_set_read_only_sync(c); mutex_unlock(&bch_register_lock); closure_return(cl); } /* * First phase of the shutdown process that's kicked off by cache_set_stop(); we * haven't waited for anything to stop yet, we're just punting to process * context to shut down block devices: */ static void __cache_set_stop1(struct closure *cl) { struct cache_set *c = container_of(cl, struct cache_set, caching); bch_blockdevs_stop(c); continue_at(cl, __cache_set_stop2, 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) { if (!test_and_set_bit(CACHE_SET_UNREGISTERING, &c->flags)) bch_cache_set_stop(c); } static unsigned cache_set_nr_devices(struct cache_set *c) { struct bch_sb_field_members *mi; unsigned i, nr = 0; mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); for (i = 0; i < c->disk_sb->nr_devices; i++) if (!bch_is_zero(mi->members[i].uuid.b, sizeof(uuid_le))) nr++; mutex_unlock(&c->sb_lock); return nr; } static unsigned cache_set_nr_online_devices(struct cache_set *c) { unsigned i, nr = 0; for (i = 0; i < c->sb.nr_devices; i++) if (c->cache[i]) nr++; return nr; } #define alloc_bucket_pages(gfp, ca) \ ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(ca)))) static struct cache_set *bch_cache_set_alloc(struct bch_sb *sb, struct cache_set_opts opts) { struct cache_set *c; unsigned iter_size, journal_entry_bytes; c = kzalloc(sizeof(struct cache_set), GFP_KERNEL); if (!c) return NULL; __module_get(THIS_MODULE); c->minor = -1; mutex_init(&c->sb_lock); INIT_RADIX_TREE(&c->devices, GFP_KERNEL); mutex_init(&c->btree_cache_lock); mutex_init(&c->bucket_lock); mutex_init(&c->btree_root_lock); INIT_WORK(&c->read_only_work, bch_cache_set_read_only_work); init_rwsem(&c->gc_lock); #define BCH_TIME_STAT(name, frequency_units, duration_units) \ spin_lock_init(&c->name##_time.lock); BCH_TIME_STATS() #undef BCH_TIME_STAT bch_open_buckets_init(c); bch_tiering_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->btree_interior_update_list); mutex_init(&c->btree_reserve_cache_lock); mutex_init(&c->btree_interior_update_lock); mutex_init(&c->bio_bounce_pages_lock); INIT_WORK(&c->bio_submit_work, bch_bio_submit_work); spin_lock_init(&c->bio_submit_lock); bio_list_init(&c->read_retry_list); spin_lock_init(&c->read_retry_lock); INIT_WORK(&c->read_retry_work, bch_read_retry_work); mutex_init(&c->zlib_workspace_lock); seqcount_init(&c->gc_pos_lock); c->prio_clock[READ].hand = 1; c->prio_clock[READ].min_prio = 0; c->prio_clock[WRITE].hand = 1; c->prio_clock[WRITE].min_prio = 0; c->congested_read_threshold_us = 2000; c->congested_write_threshold_us = 20000; c->error_limit = 16 << IO_ERROR_SHIFT; init_waitqueue_head(&c->writeback_wait); c->writeback_pages_max = (256 << 10) / PAGE_SIZE; c->copy_gc_enabled = 1; c->tiering_enabled = 1; c->tiering_percent = 10; c->foreground_target_percent = 20; c->journal.write_time = &c->journal_write_time; c->journal.delay_time = &c->journal_delay_time; c->journal.blocked_time = &c->journal_blocked_time; c->journal.flush_seq_time = &c->journal_flush_seq_time; mutex_init(&c->uevent_lock); mutex_lock(&c->sb_lock); if (bch_sb_to_cache_set(c, sb)) { mutex_unlock(&c->sb_lock); goto err; } mutex_unlock(&c->sb_lock); scnprintf(c->name, sizeof(c->name), "%pU", &c->sb.user_uuid); c->opts = cache_superblock_opts(sb); cache_set_opts_apply(&c->opts, opts); c->opts.nochanges |= c->opts.noreplay; c->opts.read_only |= c->opts.nochanges; c->block_bits = ilog2(c->sb.block_size); if (cache_set_init_fault("cache_set_alloc")) goto err; iter_size = (btree_blocks(c) + 1) * 2 * sizeof(struct btree_node_iter_set); journal_entry_bytes = 512U << BCH_SB_JOURNAL_ENTRY_SIZE(sb); if (!(c->wq = alloc_workqueue("bcache", WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_HIGHPRI, 1)) || !(c->copygc_wq = alloc_workqueue("bcache_copygc", WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_HIGHPRI, 1)) || percpu_ref_init(&c->writes, bch_writes_disabled, 0, GFP_KERNEL) || mempool_init_slab_pool(&c->search, 1, bch_search_cache) || mempool_init_kmalloc_pool(&c->btree_reserve_pool, 1, sizeof(struct btree_reserve)) || mempool_init_kmalloc_pool(&c->btree_interior_update_pool, 1, sizeof(struct btree_interior_update)) || mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) || bioset_init(&c->btree_read_bio, 1, 0) || bioset_init(&c->bio_read, 1, offsetof(struct bch_read_bio, bio)) || bioset_init(&c->bio_read_split, 1, offsetof(struct bch_read_bio, bio)) || bioset_init(&c->bio_write, 1, offsetof(struct bch_write_bio, bio)) || mempool_init_page_pool(&c->bio_bounce_pages, max_t(unsigned, c->sb.btree_node_size, BCH_ENCODED_EXTENT_MAX) / PAGE_SECTORS, 0) || !(c->bucket_stats_percpu = alloc_percpu(struct bucket_stats_cache_set)) || lg_lock_init(&c->bucket_stats_lock) || mempool_init_page_pool(&c->btree_bounce_pool, 1, ilog2(btree_pages(c))) || bdi_setup_and_register(&c->bdi, "bcache") || bch_io_clock_init(&c->io_clock[READ]) || bch_io_clock_init(&c->io_clock[WRITE]) || bch_journal_alloc(&c->journal, journal_entry_bytes) || bch_btree_cache_alloc(c) || bch_cache_set_encryption_init(c) || bch_compress_init(c) || bch_check_set_has_compressed_data(c, c->opts.compression)) goto err; c->bdi.ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE; c->bdi.congested_fn = bch_congested_fn; c->bdi.congested_data = c; /* * Now that all allocations have succeeded, init various refcounty * things that let us shutdown: */ closure_init(&c->cl, NULL); c->kobj.kset = bcache_kset; kobject_init(&c->kobj, &bch_cache_set_ktype); kobject_init(&c->internal, &bch_cache_set_internal_ktype); kobject_init(&c->opts_dir, &bch_cache_set_opts_dir_ktype); kobject_init(&c->time_stats, &bch_cache_set_time_stats_ktype); bch_cache_accounting_init(&c->accounting, &c->cl); closure_init(&c->caching, &c->cl); set_closure_fn(&c->caching, __cache_set_stop1, system_wq); continue_at_noreturn(&c->cl, __cache_set_stop3, system_wq); return c; err: cache_set_free(c); return NULL; } static int bch_cache_set_online(struct cache_set *c) { struct cache *ca; unsigned i; lockdep_assert_held(&bch_register_lock); if (c->kobj.state_in_sysfs) return 0; c->minor = idr_alloc(&bch_chardev_minor, c, 0, 0, GFP_KERNEL); if (c->minor < 0) return c->minor; c->chardev = device_create(bch_chardev_class, NULL, MKDEV(bch_chardev_major, c->minor), NULL, "bcache%u-ctl", c->minor); if (IS_ERR(c->chardev)) return PTR_ERR(c->chardev); if (kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) || kobject_add(&c->internal, &c->kobj, "internal") || kobject_add(&c->opts_dir, &c->kobj, "options") || kobject_add(&c->time_stats, &c->kobj, "time_stats") || bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj)) return -1; for_each_cache(ca, c, i) if (bch_cache_online(ca)) { percpu_ref_put(&ca->ref); return -1; } list_add(&c->list, &bch_cache_sets); return 0; } static const char *run_cache_set(struct cache_set *c) { const char *err = "cannot allocate memory"; struct bch_sb_field_members *mi; struct cache *ca; unsigned i, id; time64_t now; LIST_HEAD(journal); struct jset *j; int ret = -EINVAL; lockdep_assert_held(&bch_register_lock); BUG_ON(test_bit(CACHE_SET_RUNNING, &c->flags)); /* We don't want bch_fatal_error() to free underneath us */ closure_get(&c->caching); /* * Make sure that each cache object's mi is up to date before * we start testing it. */ for_each_cache(ca, c, i) bch_sb_from_cache_set(c, ca); if (BCH_SB_INITIALIZED(c->disk_sb)) { ret = bch_journal_read(c, &journal); if (ret) goto err; pr_debug("btree_journal_read() done"); j = &list_entry(journal.prev, struct journal_replay, list)->j; err = "error reading priorities"; for_each_cache(ca, c, i) { ret = bch_prio_read(ca); if (ret) { percpu_ref_put(&ca->ref); goto err; } } c->prio_clock[READ].hand = le16_to_cpu(j->read_clock); c->prio_clock[WRITE].hand = le16_to_cpu(j->write_clock); for_each_cache(ca, c, i) { bch_recalc_min_prio(ca, READ); bch_recalc_min_prio(ca, WRITE); } /* * If bch_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. */ for (id = 0; id < BTREE_ID_NR; id++) { unsigned level; struct bkey_i *k; err = "bad btree root"; k = bch_journal_find_btree_root(c, j, id, &level); if (!k && id == BTREE_ID_EXTENTS) goto err; if (!k) { pr_debug("missing btree root: %d", id); continue; } err = "error reading btree root"; if (bch_btree_root_read(c, id, k, level)) goto err; } bch_verbose(c, "starting mark and sweep:"); err = "error in recovery"; if (bch_initial_gc(c, &journal)) goto err; if (c->opts.noreplay) goto recovery_done; bch_verbose(c, "mark and sweep done"); /* * bch_journal_start() can't happen sooner, or btree_gc_finish() * will give spurious errors about oldest_gen > bucket_gen - * this is a hack but oh well. */ bch_journal_start(c); err = "error starting allocator thread"; for_each_cache(ca, c, i) if (ca->mi.state == BCH_MEMBER_STATE_ACTIVE && bch_cache_allocator_start(ca)) { percpu_ref_put(&ca->ref); goto err; } bch_verbose(c, "starting journal replay:"); err = "journal replay failed"; ret = bch_journal_replay(c, &journal); if (ret) goto err; bch_verbose(c, "journal replay done"); if (c->opts.norecovery) goto recovery_done; bch_verbose(c, "starting fsck:"); err = "error in fsck"; ret = bch_fsck(c, !c->opts.nofsck); if (ret) goto err; bch_verbose(c, "fsck done"); } else { struct bch_inode_unpacked inode; struct bkey_inode_buf packed_inode; struct closure cl; closure_init_stack(&cl); bch_notice(c, "initializing new filesystem"); err = "unable to allocate journal buckets"; for_each_cache(ca, c, i) if (bch_cache_journal_alloc(ca)) { percpu_ref_put(&ca->ref); goto err; } bch_initial_gc(c, NULL); /* * journal_res_get() will crash if called before this has * set up the journal.pin FIFO and journal.cur pointer: */ bch_journal_start(c); bch_journal_set_replay_done(&c->journal); err = "error starting allocator thread"; for_each_cache(ca, c, i) if (ca->mi.state == BCH_MEMBER_STATE_ACTIVE && bch_cache_allocator_start(ca)) { percpu_ref_put(&ca->ref); goto err; } err = "cannot allocate new btree root"; for (id = 0; id < BTREE_ID_NR; id++) if (bch_btree_root_alloc(c, id, &cl)) { closure_sync(&cl); goto err; } /* Wait for new btree roots to be written: */ closure_sync(&cl); bch_inode_init(c, &inode, 0, 0, S_IFDIR|S_IRWXU|S_IRUGO|S_IXUGO, 0); inode.inum = BCACHE_ROOT_INO; bch_inode_pack(&packed_inode, &inode); err = "error creating root directory"; if (bch_btree_insert(c, BTREE_ID_INODES, &packed_inode.inode.k_i, NULL, NULL, NULL, 0)) goto err; err = "error writing first journal entry"; if (bch_journal_meta(&c->journal)) goto err; } recovery_done: if (c->opts.read_only) { bch_cache_set_read_only_sync(c); } else { err = __bch_cache_set_read_write(c); if (err) goto err; } mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); now = ktime_get_seconds(); rcu_read_lock(); for_each_cache_rcu(ca, c, i) mi->members[ca->dev_idx].last_mount = cpu_to_le64(now); rcu_read_unlock(); SET_BCH_SB_INITIALIZED(c->disk_sb, true); SET_BCH_SB_CLEAN(c->disk_sb, false); c->disk_sb->version = BCACHE_SB_VERSION_CDEV; bch_write_super(c); mutex_unlock(&c->sb_lock); err = "dynamic fault"; if (cache_set_init_fault("run_cache_set")) goto err; err = "error creating kobject"; if (bch_cache_set_online(c)) goto err; err = "can't bring up blockdev volumes"; if (bch_blockdev_volumes_start(c)) goto err; bch_debug_init_cache_set(c); set_bit(CACHE_SET_RUNNING, &c->flags); bch_attach_backing_devs(c); bch_notify_cache_set_read_write(c); err = NULL; out: bch_journal_entries_free(&journal); closure_put(&c->caching); return err; err: switch (ret) { case BCH_FSCK_ERRORS_NOT_FIXED: bch_err(c, "filesystem contains errors: please report this to the developers"); pr_cont("mount with -o fix_errors to repair"); err = "fsck error"; break; case BCH_FSCK_REPAIR_UNIMPLEMENTED: bch_err(c, "filesystem contains errors: please report this to the developers"); pr_cont("repair unimplemented: inform the developers so that it can be added"); err = "fsck error"; break; case BCH_FSCK_REPAIR_IMPOSSIBLE: bch_err(c, "filesystem contains errors, but repair impossible"); err = "fsck error"; break; case BCH_FSCK_UNKNOWN_VERSION: err = "unknown metadata version";; break; case -ENOMEM: err = "cannot allocate memory"; break; case -EIO: err = "IO error"; break; } BUG_ON(!err); set_bit(CACHE_SET_ERROR, &c->flags); goto out; } static const char *can_add_cache(struct bch_sb *sb, struct cache_set *c) { struct bch_sb_field_members *sb_mi; sb_mi = bch_sb_get_members(sb); if (!sb_mi) return "Invalid superblock: member info area missing"; if (le16_to_cpu(sb->block_size) != c->sb.block_size) return "mismatched block size"; if (le16_to_cpu(sb_mi->members[sb->dev_idx].bucket_size) < BCH_SB_BTREE_NODE_SIZE(c->disk_sb)) return "new cache bucket_size is too small"; return NULL; } static const char *can_attach_cache(struct bch_sb *sb, struct cache_set *c) { struct bch_sb_field_members *mi = bch_sb_get_members(c->disk_sb); struct bch_sb_field_members *dev_mi = bch_sb_get_members(sb); uuid_le dev_uuid = dev_mi->members[sb->dev_idx].uuid; const char *err; err = can_add_cache(sb, c); if (err) return err; if (bch_is_zero(&dev_uuid, sizeof(dev_uuid))) return "device has been removed"; /* * When attaching an existing device, the cache set superblock must * already contain member_info with a matching UUID */ if (sb->dev_idx >= c->disk_sb->nr_devices || memcmp(&mi->members[sb->dev_idx].uuid, &dev_uuid, sizeof(uuid_le))) return "cache sb does not match set"; return NULL; } /* Cache device */ bool bch_cache_read_only(struct cache *ca) { struct cache_set *c = ca->set; struct bch_sb_field_members *mi; char buf[BDEVNAME_SIZE]; bdevname(ca->disk_sb.bdev, buf); lockdep_assert_held(&bch_register_lock); if (ca->mi.state != BCH_MEMBER_STATE_ACTIVE) return false; if (!bch_cache_may_remove(ca)) { bch_err(c, "required member %s going RO, forcing fs RO", buf); bch_cache_set_read_only_sync(c); } trace_bcache_cache_read_only(ca); bch_moving_gc_stop(ca); /* * This stops new data writes (e.g. to existing open data * buckets) and then waits for all existing writes to * complete. */ bch_cache_allocator_stop(ca); bch_cache_group_remove_cache(&c->journal.devs, ca); /* * Device data write barrier -- no non-meta-data writes should * occur after this point. However, writes to btree buckets, * journal buckets, and the superblock can still occur. */ trace_bcache_cache_read_only_done(ca); bch_notice(c, "%s read only", bdevname(ca->disk_sb.bdev, buf)); bch_notify_cache_read_only(ca); mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); SET_BCH_MEMBER_STATE(&mi->members[ca->dev_idx], BCH_MEMBER_STATE_RO); bch_write_super(c); mutex_unlock(&c->sb_lock); return true; } static const char *__bch_cache_read_write(struct cache_set *c, struct cache *ca) { lockdep_assert_held(&bch_register_lock); if (ca->mi.state == BCH_MEMBER_STATE_ACTIVE) return NULL; if (test_bit(CACHE_DEV_REMOVING, &ca->flags)) return "removing"; trace_bcache_cache_read_write(ca); if (bch_cache_allocator_start(ca)) return "error starting allocator thread"; if (bch_moving_gc_thread_start(ca)) return "error starting moving GC thread"; bch_cache_group_add_cache(&c->journal.devs, ca); wake_up_process(c->tiering_read); bch_notify_cache_read_write(ca); trace_bcache_cache_read_write_done(ca); return NULL; } const char *bch_cache_read_write(struct cache *ca) { struct cache_set *c = ca->set; struct bch_sb_field_members *mi; const char *err; err = __bch_cache_read_write(c, ca); if (err) return err; mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); SET_BCH_MEMBER_STATE(&mi->members[ca->dev_idx], BCH_MEMBER_STATE_ACTIVE); bch_write_super(c); mutex_unlock(&c->sb_lock); return NULL; } /* * bch_cache_stop has already returned, so we no longer hold the register * lock at the point this is called. */ void bch_cache_release(struct kobject *kobj) { struct cache *ca = container_of(kobj, struct cache, kobj); percpu_ref_exit(&ca->ref); kfree(ca); } static void bch_cache_free_work(struct work_struct *work) { struct cache *ca = container_of(work, struct cache, free_work); struct cache_set *c = ca->set; unsigned i; cancel_work_sync(&ca->io_error_work); if (c && c->kobj.state_in_sysfs) { char buf[12]; sprintf(buf, "cache%u", ca->dev_idx); sysfs_remove_link(&c->kobj, buf); } if (ca->kobj.state_in_sysfs) kobject_del(&ca->kobj); bch_free_super(&ca->disk_sb); /* * bch_cache_stop can be called in the middle of initialization * of the struct cache object. * As such, not all the sub-structures may be initialized. * However, they were zeroed when the object was allocated. */ bch_journal_free_cache(ca); free_percpu(ca->sectors_written); bioset_exit(&ca->replica_set); free_percpu(ca->bucket_stats_percpu); free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca))); kfree(ca->prio_buckets); kfree(ca->bio_prio); kfree(ca->journal.bio); vfree(ca->buckets); vfree(ca->oldest_gens); free_heap(&ca->heap); free_fifo(&ca->free_inc); for (i = 0; i < RESERVE_NR; i++) free_fifo(&ca->free[i]); kobject_put(&ca->kobj); if (c) kobject_put(&c->kobj); } static void bch_cache_percpu_ref_release(struct percpu_ref *ref) { struct cache *ca = container_of(ref, struct cache, ref); schedule_work(&ca->free_work); } static void bch_cache_free_rcu(struct rcu_head *rcu) { struct cache *ca = container_of(rcu, struct cache, free_rcu); /* * This decrements the ref count to ca, and once the ref count * is 0 (outstanding bios to the ca also incremented it and * decrement it on completion/error), bch_cache_percpu_ref_release * is called, and that eventually results in bch_cache_free_work * being called, which in turn results in bch_cache_release being * called. * * In particular, these functions won't be called until there are no * bios outstanding (the per-cpu ref counts are all 0), so it * is safe to remove the actual sysfs device at that point, * and that can indicate success to the user. */ percpu_ref_kill(&ca->ref); } static void bch_cache_stop(struct cache *ca) { struct cache_set *c = ca->set; lockdep_assert_held(&bch_register_lock); if (c) { BUG_ON(rcu_access_pointer(c->cache[ca->dev_idx]) != ca); rcu_assign_pointer(c->cache[ca->dev_idx], NULL); } call_rcu(&ca->free_rcu, bch_cache_free_rcu); } static void bch_cache_remove_work(struct work_struct *work) { struct cache *ca = container_of(work, struct cache, remove_work); struct bch_sb_field_members *mi; struct cache_set *c = ca->set; char name[BDEVNAME_SIZE]; bool force = test_bit(CACHE_DEV_FORCE_REMOVE, &ca->flags); unsigned dev_idx = ca->dev_idx; bdevname(ca->disk_sb.bdev, name); /* * Device should already be RO, now migrate data off: * * XXX: locking is sketchy, bch_cache_read_write() has to check * CACHE_DEV_REMOVING bit */ if (!ca->mi.has_data) { /* Nothing to do: */ } else if (!bch_move_data_off_device(ca)) { mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); SET_BCH_MEMBER_HAS_DATA(&mi->members[ca->dev_idx], false); bch_write_super(c); mutex_unlock(&c->sb_lock); } else if (force) { bch_flag_data_bad(ca); mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); SET_BCH_MEMBER_HAS_DATA(&mi->members[ca->dev_idx], false); bch_write_super(c); mutex_unlock(&c->sb_lock); } else { bch_err(c, "Remove of %s failed, unable to migrate data off", name); clear_bit(CACHE_DEV_REMOVING, &ca->flags); return; } /* Now metadata: */ if (!ca->mi.has_metadata) { /* Nothing to do: */ } else if (!bch_move_meta_data_off_device(ca)) { mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); SET_BCH_MEMBER_HAS_METADATA(&mi->members[ca->dev_idx], false); bch_write_super(c); mutex_unlock(&c->sb_lock); } else { bch_err(c, "Remove of %s failed, unable to migrate metadata off", name); clear_bit(CACHE_DEV_REMOVING, &ca->flags); return; } /* * Ok, really doing the remove: * Drop device's prio pointer before removing it from superblock: */ bch_notify_cache_removed(ca); spin_lock(&c->journal.lock); c->journal.prio_buckets[dev_idx] = 0; spin_unlock(&c->journal.lock); bch_journal_meta(&c->journal); /* * Stop device before removing it from the cache set's list of devices - * and get our own ref on cache set since ca is going away: */ closure_get(&c->cl); mutex_lock(&bch_register_lock); bch_cache_stop(ca); /* * RCU barrier between dropping between c->cache and dropping from * member info: */ synchronize_rcu(); lockdep_assert_held(&bch_register_lock); /* * Free this device's slot in the bch_member array - all pointers to * this device must be gone: */ mutex_lock(&c->sb_lock); mi = bch_sb_get_members(c->disk_sb); memset(&mi->members[dev_idx].uuid, 0, sizeof(mi->members[dev_idx].uuid)); bch_write_super(c); mutex_unlock(&c->sb_lock); mutex_unlock(&bch_register_lock); closure_put(&c->cl); } bool bch_cache_remove(struct cache *ca, bool force) { mutex_lock(&bch_register_lock); if (test_bit(CACHE_DEV_REMOVING, &ca->flags)) return false; if (!bch_cache_may_remove(ca)) { bch_err(ca->set, "Can't remove last device in tier %u", ca->mi.tier); bch_notify_cache_remove_failed(ca); return false; } /* First, go RO before we try to migrate data off: */ bch_cache_read_only(ca); if (force) set_bit(CACHE_DEV_FORCE_REMOVE, &ca->flags); set_bit(CACHE_DEV_REMOVING, &ca->flags); bch_notify_cache_removing(ca); mutex_unlock(&bch_register_lock); /* Migrate the data and finish removal asynchronously: */ queue_work(system_long_wq, &ca->remove_work); return true; } static int bch_cache_online(struct cache *ca) { char buf[12]; lockdep_assert_held(&bch_register_lock); sprintf(buf, "cache%u", ca->dev_idx); if (kobject_add(&ca->kobj, &part_to_dev(ca->disk_sb.bdev->bd_part)->kobj, "bcache") || sysfs_create_link(&ca->kobj, &ca->set->kobj, "set") || sysfs_create_link(&ca->set->kobj, &ca->kobj, buf)) return -1; return 0; } static const char *cache_alloc(struct bcache_superblock *sb, struct cache_set *c, struct cache **ret) { struct bch_member *member; size_t reserve_none, movinggc_reserve, free_inc_reserve, total_reserve; size_t heap_size; unsigned i; const char *err = "cannot allocate memory"; struct cache *ca; if (c->sb.nr_devices == 1) bdevname(sb->bdev, c->name); if (cache_set_init_fault("cache_alloc")) return err; ca = kzalloc(sizeof(*ca), GFP_KERNEL); if (!ca) return err; if (percpu_ref_init(&ca->ref, bch_cache_percpu_ref_release, 0, GFP_KERNEL)) { kfree(ca); return err; } kobject_init(&ca->kobj, &bch_cache_ktype); spin_lock_init(&ca->self.lock); ca->self.nr_devices = 1; rcu_assign_pointer(ca->self.d[0].dev, ca); ca->dev_idx = sb->sb->dev_idx; INIT_WORK(&ca->free_work, bch_cache_free_work); INIT_WORK(&ca->remove_work, bch_cache_remove_work); spin_lock_init(&ca->freelist_lock); spin_lock_init(&ca->prio_buckets_lock); mutex_init(&ca->heap_lock); bch_moving_init_cache(ca); ca->disk_sb = *sb; ca->disk_sb.bdev->bd_holder = ca; memset(sb, 0, sizeof(*sb)); INIT_WORK(&ca->io_error_work, bch_nonfatal_io_error_work); err = "dynamic fault"; if (cache_set_init_fault("cache_alloc")) goto err; member = bch_sb_get_members(ca->disk_sb.sb)->members + ca->disk_sb.sb->dev_idx; ca->mi = cache_mi_to_cpu_mi(member); ca->uuid = member->uuid; ca->bucket_bits = ilog2(ca->mi.bucket_size); /* XXX: tune these */ movinggc_reserve = max_t(size_t, 16, ca->mi.nbuckets >> 7); reserve_none = max_t(size_t, 4, ca->mi.nbuckets >> 9); /* * free_inc must be smaller than the copygc reserve: if it was bigger, * one copygc iteration might not make enough buckets available to fill * up free_inc and allow the allocator to make forward progress */ free_inc_reserve = movinggc_reserve / 2; heap_size = movinggc_reserve * 8; if (!init_fifo(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || !init_fifo(&ca->free[RESERVE_BTREE], BTREE_NODE_RESERVE, GFP_KERNEL) || !init_fifo(&ca->free[RESERVE_MOVINGGC], movinggc_reserve, GFP_KERNEL) || !init_fifo(&ca->free[RESERVE_NONE], reserve_none, GFP_KERNEL) || !init_fifo(&ca->free_inc, free_inc_reserve, GFP_KERNEL) || !init_heap(&ca->heap, heap_size, GFP_KERNEL) || !(ca->oldest_gens = vzalloc(sizeof(u8) * ca->mi.nbuckets)) || !(ca->buckets = vzalloc(sizeof(struct bucket) * ca->mi.nbuckets)) || !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) * 2, GFP_KERNEL)) || !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)) || !(ca->bucket_stats_percpu = alloc_percpu(struct bucket_stats_cache)) || !(ca->bio_prio = bio_kmalloc(GFP_NOIO, bucket_pages(ca))) || bioset_init(&ca->replica_set, 4, offsetof(struct bch_write_bio, bio)) || !(ca->sectors_written = alloc_percpu(*ca->sectors_written)) || bch_journal_init_cache(ca)) goto err; ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca); total_reserve = ca->free_inc.size; for (i = 0; i < RESERVE_NR; i++) total_reserve += ca->free[i].size; pr_debug("%zu buckets reserved", total_reserve); ca->copygc_write_point.group = &ca->self; ca->tiering_write_point.group = &ca->self; /* * Increase journal write timeout if flushes to this device are * expensive: */ if (!blk_queue_nonrot(bdev_get_queue(ca->disk_sb.bdev)) && journal_flushes_device(ca)) c->journal.write_delay_ms = max(c->journal.write_delay_ms, 1000U); kobject_get(&c->kobj); ca->set = c; kobject_get(&ca->kobj); rcu_assign_pointer(c->cache[ca->dev_idx], ca); mutex_lock(&c->sb_lock); if (le64_to_cpu(ca->disk_sb.sb->seq) > le64_to_cpu(c->disk_sb->seq)) bch_sb_to_cache_set(c, ca->disk_sb.sb); mutex_unlock(&c->sb_lock); err = "error creating kobject"; if (c->kobj.state_in_sysfs && bch_cache_online(ca)) goto err; if (ret) *ret = ca; else kobject_put(&ca->kobj); return NULL; err: bch_cache_stop(ca); return err; } static struct cache_set *cache_set_lookup(uuid_le uuid) { struct cache_set *c; lockdep_assert_held(&bch_register_lock); list_for_each_entry(c, &bch_cache_sets, list) if (!memcmp(&c->disk_sb->uuid, &uuid, sizeof(uuid_le))) return c; return NULL; } static const char *register_cache(struct bcache_superblock *sb, struct cache_set_opts opts) { char name[BDEVNAME_SIZE]; const char *err; struct cache_set *c; bool allocated_cache_set = false; err = bch_validate_cache_super(sb); if (err) return err; bdevname(sb->bdev, name); c = cache_set_lookup(sb->sb->uuid); if (c) { err = can_attach_cache(sb->sb, c); if (err) return err; } else { c = bch_cache_set_alloc(sb->sb, opts); if (!c) return "cannot allocate memory"; allocated_cache_set = true; } err = cache_alloc(sb, c, NULL); if (err) goto err; if (cache_set_nr_online_devices(c) == cache_set_nr_devices(c)) { err = run_cache_set(c); if (err) goto err; } else { err = "error creating kobject"; if (bch_cache_set_online(c)) goto err; } bch_info(c, "started"); return NULL; err: if (allocated_cache_set) bch_cache_set_stop(c); return err; } int bch_cache_set_add_cache(struct cache_set *c, const char *path) { struct bcache_superblock sb; const char *err; struct cache *ca; struct bch_sb_field *f; struct bch_sb_field_members *mi, *dev_mi; struct bch_member saved_mi; unsigned dev_idx, nr_devices, u64s; int ret = -EINVAL; mutex_lock(&bch_register_lock); err = bch_read_super(&sb, c->opts, path); if (err) goto err_unlock_register; err = bch_validate_cache_super(&sb); if (err) goto err_unlock_register; mutex_lock(&c->sb_lock); err = can_add_cache(sb.sb, c); if (err) goto err_unlock; /* * Preserve the old cache member information (esp. tier) * before we start bashing the disk stuff. */ dev_mi = bch_sb_get_members(sb.sb); saved_mi = dev_mi->members[sb.sb->dev_idx]; saved_mi.last_mount = cpu_to_le64(ktime_get_seconds()); down_read(&c->gc_lock); if (dynamic_fault("bcache:add:no_slot")) goto no_slot; if (test_bit(CACHE_SET_GC_FAILURE, &c->flags)) goto no_slot; mi = bch_sb_get_members(c->disk_sb); for (dev_idx = 0; dev_idx < BCH_SB_MEMBERS_MAX; dev_idx++) if (dev_idx >= c->sb.nr_devices || bch_is_zero(mi->members[dev_idx].uuid.b, sizeof(uuid_le))) goto have_slot; no_slot: up_read(&c->gc_lock); err = "no slots available in superblock"; ret = -ENOSPC; goto err_unlock; have_slot: up_read(&c->gc_lock); nr_devices = max_t(unsigned, dev_idx + 1, c->sb.nr_devices); u64s = (sizeof(struct bch_sb_field_members) + sizeof(struct bch_member) * nr_devices) / sizeof(u64); err = "no space in superblock for member info"; f = bch_fs_sb_field_resize(c, &mi->field, u64s); if (!f) goto err_unlock; mi = container_of(f, struct bch_sb_field_members, field); f = bch_dev_sb_field_resize(&sb, &dev_mi->field, u64s); if (!f) goto err_unlock; dev_mi = container_of(f, struct bch_sb_field_members, field); memcpy(dev_mi, mi, u64s * sizeof(u64)); dev_mi->members[dev_idx] = saved_mi; sb.sb->dev_idx = dev_idx; sb.sb->nr_devices = nr_devices; if (bch_cache_set_mi_update(c, dev_mi->members, nr_devices)) { err = "cannot allocate memory"; ret = -ENOMEM; goto err_unlock; } /* commit new member info */ memcpy(mi, dev_mi, u64s * sizeof(u64)); c->disk_sb->nr_devices = nr_devices; c->sb.nr_devices = nr_devices; err = cache_alloc(&sb, c, &ca); if (err) goto err_unlock; bch_write_super(c); err = "journal alloc failed"; if (bch_cache_journal_alloc(ca)) goto err_put; bch_notify_cache_added(ca); if (ca->mi.state == BCH_MEMBER_STATE_ACTIVE) { err = __bch_cache_read_write(c, ca); if (err) goto err_put; } kobject_put(&ca->kobj); mutex_unlock(&c->sb_lock); mutex_unlock(&bch_register_lock); return 0; err_put: bch_cache_stop(ca); err_unlock: mutex_unlock(&c->sb_lock); err_unlock_register: mutex_unlock(&bch_register_lock); bch_free_super(&sb); bch_err(c, "Unable to add device: %s", err); return ret ?: -EINVAL; } const char *bch_register_cache_set(char * const *devices, unsigned nr_devices, struct cache_set_opts opts, struct cache_set **ret) { const char *err; struct cache_set *c = NULL; struct bcache_superblock *sb; uuid_le uuid; unsigned i; memset(&uuid, 0, sizeof(uuid_le)); if (!nr_devices) return "need at least one device"; if (!try_module_get(THIS_MODULE)) return "module unloading"; err = "cannot allocate memory"; sb = kcalloc(nr_devices, sizeof(*sb), GFP_KERNEL); if (!sb) goto err; /* * bch_read_super() needs to happen under register_lock, so that the * exclusive open is atomic with adding the new cache set to the list of * cache sets: */ mutex_lock(&bch_register_lock); for (i = 0; i < nr_devices; i++) { err = bch_read_super(&sb[i], opts, devices[i]); if (err) goto err_unlock; err = "attempting to register backing device"; if (__SB_IS_BDEV(le64_to_cpu(sb[i].sb->version))) goto err_unlock; err = bch_validate_cache_super(&sb[i]); if (err) goto err_unlock; } err = "cache set already registered"; if (cache_set_lookup(sb->sb->uuid)) goto err_unlock; err = "cannot allocate memory"; c = bch_cache_set_alloc(sb[0].sb, opts); if (!c) goto err_unlock; for (i = 0; i < nr_devices; i++) { err = cache_alloc(&sb[i], c, NULL); if (err) goto err_unlock; } err = "insufficient devices"; if (cache_set_nr_online_devices(c) != cache_set_nr_devices(c)) goto err_unlock; err = run_cache_set(c); if (err) goto err_unlock; err = "error creating kobject"; if (bch_cache_set_online(c)) goto err_unlock; if (ret) { closure_get(&c->cl); *ret = c; } mutex_unlock(&bch_register_lock); err = NULL; out: kfree(sb); module_put(THIS_MODULE); if (err) c = NULL; return err; err_unlock: if (c) bch_cache_set_stop(c); mutex_unlock(&bch_register_lock); err: for (i = 0; i < nr_devices; i++) bch_free_super(&sb[i]); goto out; } const char *bch_register_one(const char *path) { struct bcache_superblock sb; struct cache_set_opts opts = cache_set_opts_empty(); const char *err; mutex_lock(&bch_register_lock); err = bch_read_super(&sb, opts, path); if (err) goto err; if (__SB_IS_BDEV(le64_to_cpu(sb.sb->version))) err = bch_backing_dev_register(&sb); else err = register_cache(&sb, opts); bch_free_super(&sb); err: mutex_unlock(&bch_register_lock); return err; } /* Global interfaces/init */ #define kobj_attribute_write(n, fn) \ static struct kobj_attribute ksysfs_##n = __ATTR(n, S_IWUSR, NULL, fn) #define kobj_attribute_rw(n, show, store) \ static struct kobj_attribute ksysfs_##n = \ __ATTR(n, S_IWUSR|S_IRUSR, show, store) static ssize_t register_bcache(struct kobject *, struct kobj_attribute *, const char *, size_t); kobj_attribute_write(register, register_bcache); kobj_attribute_write(register_quiet, register_bcache); static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, const char *buffer, size_t size) { ssize_t ret = -EINVAL; const char *err = "cannot allocate memory"; char *path = NULL; if (!try_module_get(THIS_MODULE)) return -EBUSY; if (!(path = kstrndup(skip_spaces(buffer), size, GFP_KERNEL))) goto err; err = bch_register_one(strim(path)); if (err) goto err; ret = size; out: kfree(path); module_put(THIS_MODULE); return ret; err: pr_err("error opening %s: %s", path, err); 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) { struct cache_set *c; mutex_lock(&bch_register_lock); if (!list_empty(&bch_cache_sets)) pr_info("Setting all devices read only:"); list_for_each_entry(c, &bch_cache_sets, list) bch_cache_set_read_only(c); list_for_each_entry(c, &bch_cache_sets, list) bch_cache_set_read_only_sync(c); 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 ssize_t reboot_test(struct kobject *k, struct kobj_attribute *attr, const char *buffer, size_t size) { bcache_reboot(NULL, SYS_DOWN, NULL); return size; } kobj_attribute_write(reboot, reboot_test); static void bcache_exit(void) { bch_debug_exit(); bch_fs_exit(); bch_blockdev_exit(); if (bcache_kset) kset_unregister(bcache_kset); if (bcache_io_wq) destroy_workqueue(bcache_io_wq); if (!IS_ERR_OR_NULL(bch_chardev_class)) device_destroy(bch_chardev_class, MKDEV(bch_chardev_major, 0)); if (!IS_ERR_OR_NULL(bch_chardev_class)) class_destroy(bch_chardev_class); if (bch_chardev_major > 0) unregister_chrdev(bch_chardev_major, "bcache"); if (!IS_ERR_OR_NULL(bch_sha256)) crypto_free_shash(bch_sha256); unregister_reboot_notifier(&reboot); } static int __init bcache_init(void) { static const struct attribute *files[] = { &ksysfs_register.attr, &ksysfs_register_quiet.attr, &ksysfs_reboot.attr, NULL }; mutex_init(&bch_register_lock); register_reboot_notifier(&reboot); closure_debug_init(); bkey_pack_test(); bch_sha256 = crypto_alloc_shash("sha256", 0, 0); if (IS_ERR(bch_sha256)) goto err; bch_chardev_major = register_chrdev(0, "bcache-ctl", &bch_chardev_fops); if (bch_chardev_major < 0) goto err; bch_chardev_class = class_create(THIS_MODULE, "bcache"); if (IS_ERR(bch_chardev_class)) goto err; bch_chardev = device_create(bch_chardev_class, NULL, MKDEV(bch_chardev_major, 255), NULL, "bcache-ctl"); if (IS_ERR(bch_chardev)) goto err; if (!(bcache_io_wq = create_freezable_workqueue("bcache_io")) || !(bcache_kset = kset_create_and_add("bcache", NULL, fs_kobj)) || sysfs_create_files(&bcache_kset->kobj, files) || bch_blockdev_init() || bch_fs_init() || bch_debug_init()) goto err; return 0; err: bcache_exit(); return -ENOMEM; } #define BCH_DEBUG_PARAM(name, description) \ bool bch_##name; \ module_param_named(name, bch_##name, bool, 0644); \ MODULE_PARM_DESC(name, description); BCH_DEBUG_PARAMS() #undef BCH_DEBUG_PARAM module_exit(bcache_exit); module_init(bcache_init);