/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _BCACHE_H #define _BCACHE_H /* * SOME HIGH LEVEL CODE DOCUMENTATION: * * Bcache mostly works with cache sets, cache devices, and backing devices. * * Support for multiple cache devices hasn't quite been finished off yet, but * it's about 95% plumbed through. A cache set and its cache devices is sort of * like a md raid array and its component devices. Most of the code doesn't care * about individual cache devices, the main abstraction is the cache set. * * Multiple cache devices is intended to give us the ability to mirror dirty * cached data and metadata, without mirroring clean cached data. * * Backing devices are different, in that they have a lifetime independent of a * cache set. When you register a newly formatted backing device it'll come up * in passthrough mode, and then you can attach and detach a backing device from * a cache set at runtime - while it's mounted and in use. Detaching implicitly * invalidates any cached data for that backing device. * * A cache set can have multiple (many) backing devices attached to it. * * There's also flash only volumes - this is the reason for the distinction * between struct cached_dev and struct bcache_device. A flash only volume * works much like a bcache device that has a backing device, except the * "cached" data is always dirty. The end result is that we get thin * provisioning with very little additional code. * * Flash only volumes work but they're not production ready because the moving * garbage collector needs more work. More on that later. * * BUCKETS/ALLOCATION: * * Bcache is primarily designed for caching, which means that in normal * operation all of our available space will be allocated. Thus, we need an * efficient way of deleting things from the cache so we can write new things to * it. * * To do this, we first divide the cache device up into buckets. A bucket is the * unit of allocation; they're typically around 1 mb - anywhere from 128k to 2M+ * works efficiently. * * Each bucket has a 16 bit priority, and an 8 bit generation associated with * it. The gens and priorities for all the buckets are stored contiguously and * packed on disk (in a linked list of buckets - aside from the superblock, all * of bcache's metadata is stored in buckets). * * The priority is used to implement an LRU. We reset a bucket's priority when * we allocate it or on cache it, and every so often we decrement the priority * of each bucket. It could be used to implement something more sophisticated, * if anyone ever gets around to it. * * The generation is used for invalidating buckets. Each pointer also has an 8 * bit generation embedded in it; for a pointer to be considered valid, its gen * must match the gen of the bucket it points into. Thus, to reuse a bucket all * we have to do is increment its gen (and write its new gen to disk; we batch * this up). * * Bcache is entirely COW - we never write twice to a bucket, even buckets that * contain metadata (including btree nodes). * * THE BTREE: * * Bcache is in large part design around the btree. * * At a high level, the btree is just an index of key -> ptr tuples. * * Keys represent extents, and thus have a size field. Keys also have a variable * number of pointers attached to them (potentially zero, which is handy for * invalidating the cache). * * The key itself is an inode:offset pair. The inode number corresponds to a * backing device or a flash only volume. The offset is the ending offset of the * extent within the inode - not the starting offset; this makes lookups * slightly more convenient. * * Pointers contain the cache device id, the offset on that device, and an 8 bit * generation number. More on the gen later. * * Index lookups are not fully abstracted - cache lookups in particular are * still somewhat mixed in with the btree code, but things are headed in that * direction. * * Updates are fairly well abstracted, though. There are two different ways of * updating the btree; insert and replace. * * BTREE_INSERT will just take a list of keys and insert them into the btree - * overwriting (possibly only partially) any extents they overlap with. This is * used to update the index after a write. * * BTREE_REPLACE is really cmpxchg(); it inserts a key into the btree iff it is * overwriting a key that matches another given key. This is used for inserting * data into the cache after a cache miss, and for background writeback, and for * the moving garbage collector. * * There is no "delete" operation; deleting things from the index is * accomplished by either by invalidating pointers (by incrementing a bucket's * gen) or by inserting a key with 0 pointers - which will overwrite anything * previously present at that location in the index. * * This means that there are always stale/invalid keys in the btree. They're * filtered out by the code that iterates through a btree node, and removed when * a btree node is rewritten. * * BTREE NODES: * * Our unit of allocation is a bucket, and we we can't arbitrarily allocate and * free smaller than a bucket - so, that's how big our btree nodes are. * * (If buckets are really big we'll only use part of the bucket for a btree node * - no less than 1/4th - but a bucket still contains no more than a single * btree node. I'd actually like to change this, but for now we rely on the * bucket's gen for deleting btree nodes when we rewrite/split a node.) * * Anyways, btree nodes are big - big enough to be inefficient with a textbook * btree implementation. * * The way this is solved is that btree nodes are internally log structured; we * can append new keys to an existing btree node without rewriting it. This * means each set of keys we write is sorted, but the node is not. * * We maintain this log structure in memory - keeping 1Mb of keys sorted would * be expensive, and we have to distinguish between the keys we have written and * the keys we haven't. So to do a lookup in a btree node, we have to search * each sorted set. But we do merge written sets together lazily, so the cost of * these extra searches is quite low (normally most of the keys in a btree node * will be in one big set, and then there'll be one or two sets that are much * smaller). * * This log structure makes bcache's btree more of a hybrid between a * conventional btree and a compacting data structure, with some of the * advantages of both. * * GARBAGE COLLECTION: * * We can't just invalidate any bucket - it might contain dirty data or * metadata. If it once contained dirty data, other writes might overwrite it * later, leaving no valid pointers into that bucket in the index. * * Thus, the primary purpose of garbage collection is to find buckets to reuse. * It also counts how much valid data it each bucket currently contains, so that * allocation can reuse buckets sooner when they've been mostly overwritten. * * It also does some things that are really internal to the btree * implementation. If a btree node contains pointers that are stale by more than * some threshold, it rewrites the btree node to avoid the bucket's generation * wrapping around. It also merges adjacent btree nodes if they're empty enough. * * THE JOURNAL: * * Bcache's journal is not necessary for consistency; we always strictly * order metadata writes so that the btree and everything else is consistent on * disk in the event of an unclean shutdown, and in fact bcache had writeback * caching (with recovery from unclean shutdown) before journalling was * implemented. * * Rather, the journal is purely a performance optimization; we can't complete a * write until we've updated the index on disk, otherwise the cache would be * inconsistent in the event of an unclean shutdown. This means that without the * journal, on random write workloads we constantly have to update all the leaf * nodes in the btree, and those writes will be mostly empty (appending at most * a few keys each) - highly inefficient in terms of amount of metadata writes, * and it puts more strain on the various btree resorting/compacting code. * * The journal is just a log of keys we've inserted; on startup we just reinsert * all the keys in the open journal entries. That means that when we're updating * a node in the btree, we can wait until a 4k block of keys fills up before * writing them out. * * For simplicity, we only journal updates to leaf nodes; updates to parent * nodes are rare enough (since our leaf nodes are huge) that it wasn't worth * the complexity to deal with journalling them (in particular, journal replay) * - updates to non leaf nodes just happen synchronously (see btree_split()). */ #define pr_fmt(fmt) "bcache: %s() " fmt, __func__ #include #include #include #include #include #include #include #include #include #include #include #include "bset.h" #include "util.h" #include "closure.h" struct bucket { atomic_t pin; uint16_t prio; uint8_t gen; uint8_t last_gc; /* Most out of date gen in the btree */ uint16_t gc_mark; /* Bitfield used by GC. See below for field */ }; /* * I'd use bitfields for these, but I don't trust the compiler not to screw me * as multiple threads touch struct bucket without locking */ BITMASK(GC_MARK, struct bucket, gc_mark, 0, 2); #define GC_MARK_RECLAIMABLE 1 #define GC_MARK_DIRTY 2 #define GC_MARK_METADATA 3 #define GC_SECTORS_USED_SIZE 13 #define MAX_GC_SECTORS_USED (~(~0ULL << GC_SECTORS_USED_SIZE)) BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, GC_SECTORS_USED_SIZE); BITMASK(GC_MOVE, struct bucket, gc_mark, 15, 1); #include "journal.h" #include "stats.h" struct search; struct btree; struct keybuf; struct keybuf_key { struct rb_node node; BKEY_PADDED(key); void *private; }; struct keybuf { struct bkey last_scanned; spinlock_t lock; /* * Beginning and end of range in rb tree - so that we can skip taking * lock and checking the rb tree when we need to check for overlapping * keys. */ struct bkey start; struct bkey end; struct rb_root keys; #define KEYBUF_NR 500 DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR); }; struct bcache_device { struct closure cl; struct kobject kobj; struct cache_set *c; unsigned int id; #define BCACHEDEVNAME_SIZE 12 char name[BCACHEDEVNAME_SIZE]; struct gendisk *disk; unsigned long flags; #define BCACHE_DEV_CLOSING 0 #define BCACHE_DEV_DETACHING 1 #define BCACHE_DEV_UNLINK_DONE 2 #define BCACHE_DEV_WB_RUNNING 3 #define BCACHE_DEV_RATE_DW_RUNNING 4 int nr_stripes; #define BCH_MIN_STRIPE_SZ ((4 << 20) >> SECTOR_SHIFT) unsigned int stripe_size; atomic_t *stripe_sectors_dirty; unsigned long *full_dirty_stripes; struct bio_set bio_split; unsigned int data_csum:1; int (*cache_miss)(struct btree *b, struct search *s, struct bio *bio, unsigned int sectors); int (*ioctl)(struct bcache_device *d, fmode_t mode, unsigned int cmd, unsigned long arg); }; struct io { /* Used to track sequential IO so it can be skipped */ struct hlist_node hash; struct list_head lru; unsigned long jiffies; unsigned int sequential; sector_t last; }; enum stop_on_failure { BCH_CACHED_DEV_STOP_AUTO = 0, BCH_CACHED_DEV_STOP_ALWAYS, BCH_CACHED_DEV_STOP_MODE_MAX, }; struct cached_dev { struct list_head list; struct bcache_device disk; struct block_device *bdev; struct cache_sb sb; struct cache_sb_disk *sb_disk; struct bio sb_bio; struct bio_vec sb_bv[1]; struct closure sb_write; struct semaphore sb_write_mutex; /* Refcount on the cache set. Always nonzero when we're caching. */ refcount_t count; struct work_struct detach; /* * Device might not be running if it's dirty and the cache set hasn't * showed up yet. */ atomic_t running; /* * Writes take a shared lock from start to finish; scanning for dirty * data to refill the rb tree requires an exclusive lock. */ struct rw_semaphore writeback_lock; /* * Nonzero, and writeback has a refcount (d->count), iff there is dirty * data in the cache. Protected by writeback_lock; must have an * shared lock to set and exclusive lock to clear. */ atomic_t has_dirty; #define BCH_CACHE_READA_ALL 0 #define BCH_CACHE_READA_META_ONLY 1 unsigned int cache_readahead_policy; struct bch_ratelimit writeback_rate; struct delayed_work writeback_rate_update; /* Limit number of writeback bios in flight */ struct semaphore in_flight; struct task_struct *writeback_thread; struct workqueue_struct *writeback_write_wq; struct keybuf writeback_keys; struct task_struct *status_update_thread; /* * Order the write-half of writeback operations strongly in dispatch * order. (Maintain LBA order; don't allow reads completing out of * order to re-order the writes...) */ struct closure_waitlist writeback_ordering_wait; atomic_t writeback_sequence_next; /* For tracking sequential IO */ #define RECENT_IO_BITS 7 #define RECENT_IO (1 << RECENT_IO_BITS) struct io io[RECENT_IO]; struct hlist_head io_hash[RECENT_IO + 1]; struct list_head io_lru; spinlock_t io_lock; struct cache_accounting accounting; /* The rest of this all shows up in sysfs */ unsigned int sequential_cutoff; unsigned int readahead; unsigned int io_disable:1; unsigned int verify:1; unsigned int bypass_torture_test:1; unsigned int partial_stripes_expensive:1; unsigned int writeback_metadata:1; unsigned int writeback_running:1; unsigned char writeback_percent; unsigned int writeback_delay; uint64_t writeback_rate_target; int64_t writeback_rate_proportional; int64_t writeback_rate_integral; int64_t writeback_rate_integral_scaled; int32_t writeback_rate_change; unsigned int writeback_rate_update_seconds; unsigned int writeback_rate_i_term_inverse; unsigned int writeback_rate_p_term_inverse; unsigned int writeback_rate_minimum; enum stop_on_failure stop_when_cache_set_failed; #define DEFAULT_CACHED_DEV_ERROR_LIMIT 64 atomic_t io_errors; unsigned int error_limit; unsigned int offline_seconds; char backing_dev_name[BDEVNAME_SIZE]; }; enum alloc_reserve { RESERVE_BTREE, RESERVE_PRIO, RESERVE_MOVINGGC, RESERVE_NONE, RESERVE_NR, }; struct cache { struct cache_set *set; struct cache_sb sb; struct cache_sb_disk *sb_disk; struct bio sb_bio; struct bio_vec sb_bv[1]; struct kobject kobj; struct block_device *bdev; struct task_struct *alloc_thread; struct closure prio; struct prio_set *disk_buckets; /* * When allocating new buckets, prio_write() gets first dibs - since we * may not be allocate at all without writing priorities and gens. * prio_last_buckets[] contains the last buckets we wrote priorities to * (so gc can mark them as metadata), prio_buckets[] contains the * buckets allocated for the next prio write. */ uint64_t *prio_buckets; uint64_t *prio_last_buckets; /* * free: Buckets that are ready to be used * * free_inc: Incoming buckets - these are buckets that currently have * cached data in them, and we can't reuse them until after we write * their new gen to disk. After prio_write() finishes writing the new * gens/prios, they'll be moved to the free list (and possibly discarded * in the process) */ DECLARE_FIFO(long, free)[RESERVE_NR]; DECLARE_FIFO(long, free_inc); size_t fifo_last_bucket; /* Allocation stuff: */ struct bucket *buckets; DECLARE_HEAP(struct bucket *, heap); /* * If nonzero, we know we aren't going to find any buckets to invalidate * until a gc finishes - otherwise we could pointlessly burn a ton of * cpu */ unsigned int invalidate_needs_gc; bool discard; /* Get rid of? */ struct journal_device journal; /* The rest of this all shows up in sysfs */ #define IO_ERROR_SHIFT 20 atomic_t io_errors; atomic_t io_count; atomic_long_t meta_sectors_written; atomic_long_t btree_sectors_written; atomic_long_t sectors_written; char cache_dev_name[BDEVNAME_SIZE]; }; struct gc_stat { size_t nodes; size_t nodes_pre; size_t key_bytes; size_t nkeys; uint64_t data; /* sectors */ unsigned int in_use; /* percent */ }; /* * Flag bits, for how the cache set is shutting down, and what phase it's at: * * CACHE_SET_UNREGISTERING means we're not just shutting down, we're detaching * all the backing devices first (their cached data gets invalidated, and they * won't automatically reattach). * * CACHE_SET_STOPPING always gets set first when we're closing down a cache set; * we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e. * flushing dirty data). * * CACHE_SET_RUNNING means all cache devices have been registered and journal * replay is complete. * * CACHE_SET_IO_DISABLE is set when bcache is stopping the whold cache set, all * external and internal I/O should be denied when this flag is set. * */ #define CACHE_SET_UNREGISTERING 0 #define CACHE_SET_STOPPING 1 #define CACHE_SET_RUNNING 2 #define CACHE_SET_IO_DISABLE 3 struct cache_set { struct closure cl; struct list_head list; struct kobject kobj; struct kobject internal; struct dentry *debug; struct cache_accounting accounting; unsigned long flags; atomic_t idle_counter; atomic_t at_max_writeback_rate; struct cache *cache; struct bcache_device **devices; unsigned int devices_max_used; atomic_t attached_dev_nr; struct list_head cached_devs; uint64_t cached_dev_sectors; atomic_long_t flash_dev_dirty_sectors; struct closure caching; struct closure sb_write; struct semaphore sb_write_mutex; mempool_t search; mempool_t bio_meta; struct bio_set bio_split; /* For the btree cache */ struct shrinker shrink; /* For the btree cache and anything allocation related */ struct mutex bucket_lock; /* log2(bucket_size), in sectors */ unsigned short bucket_bits; /* log2(block_size), in sectors */ unsigned short block_bits; /* * Default number of pages for a new btree node - may be less than a * full bucket */ unsigned int btree_pages; /* * Lists of struct btrees; lru is the list for structs that have memory * allocated for actual btree node, freed is for structs that do not. * * We never free a struct btree, except on shutdown - we just put it on * the btree_cache_freed list and reuse it later. This simplifies the * code, and it doesn't cost us much memory as the memory usage is * dominated by buffers that hold the actual btree node data and those * can be freed - and the number of struct btrees allocated is * effectively bounded. * * btree_cache_freeable effectively is a small cache - we use it because * high order page allocations can be rather expensive, and it's quite * common to delete and allocate btree nodes in quick succession. It * should never grow past ~2-3 nodes in practice. */ struct list_head btree_cache; struct list_head btree_cache_freeable; struct list_head btree_cache_freed; /* Number of elements in btree_cache + btree_cache_freeable lists */ unsigned int btree_cache_used; /* * If we need to allocate memory for a new btree node and that * allocation fails, we can cannibalize another node in the btree cache * to satisfy the allocation - lock to guarantee only one thread does * this at a time: */ wait_queue_head_t btree_cache_wait; struct task_struct *btree_cache_alloc_lock; spinlock_t btree_cannibalize_lock; /* * When we free a btree node, we increment the gen of the bucket the * node is in - but we can't rewrite the prios and gens until we * finished whatever it is we were doing, otherwise after a crash the * btree node would be freed but for say a split, we might not have the * pointers to the new nodes inserted into the btree yet. * * This is a refcount that blocks prio_write() until the new keys are * written. */ atomic_t prio_blocked; wait_queue_head_t bucket_wait; /* * For any bio we don't skip we subtract the number of sectors from * rescale; when it hits 0 we rescale all the bucket priorities. */ atomic_t rescale; /* * used for GC, identify if any front side I/Os is inflight */ atomic_t search_inflight; /* * When we invalidate buckets, we use both the priority and the amount * of good data to determine which buckets to reuse first - to weight * those together consistently we keep track of the smallest nonzero * priority of any bucket. */ uint16_t min_prio; /* * max(gen - last_gc) for all buckets. When it gets too big we have to * gc to keep gens from wrapping around. */ uint8_t need_gc; struct gc_stat gc_stats; size_t nbuckets; size_t avail_nbuckets; struct task_struct *gc_thread; /* Where in the btree gc currently is */ struct bkey gc_done; /* * For automatical garbage collection after writeback completed, this * varialbe is used as bit fields, * - 0000 0001b (BCH_ENABLE_AUTO_GC): enable gc after writeback * - 0000 0010b (BCH_DO_AUTO_GC): do gc after writeback * This is an optimization for following write request after writeback * finished, but read hit rate dropped due to clean data on cache is * discarded. Unless user explicitly sets it via sysfs, it won't be * enabled. */ #define BCH_ENABLE_AUTO_GC 1 #define BCH_DO_AUTO_GC 2 uint8_t gc_after_writeback; /* * The allocation code needs gc_mark in struct bucket to be correct, but * it's not while a gc is in progress. Protected by bucket_lock. */ int gc_mark_valid; /* Counts how many sectors bio_insert has added to the cache */ atomic_t sectors_to_gc; wait_queue_head_t gc_wait; struct keybuf moving_gc_keys; /* Number of moving GC bios in flight */ struct semaphore moving_in_flight; struct workqueue_struct *moving_gc_wq; struct btree *root; #ifdef CONFIG_BCACHE_DEBUG struct btree *verify_data; struct bset *verify_ondisk; struct mutex verify_lock; #endif uint8_t set_uuid[16]; unsigned int nr_uuids; struct uuid_entry *uuids; BKEY_PADDED(uuid_bucket); struct closure uuid_write; struct semaphore uuid_write_mutex; /* * A btree node on disk could have too many bsets for an iterator to fit * on the stack - have to dynamically allocate them. * bch_cache_set_alloc() will make sure the pool can allocate iterators * equipped with enough room that can host * (sb.bucket_size / sb.block_size) * btree_iter_sets, which is more than static MAX_BSETS. */ mempool_t fill_iter; struct bset_sort_state sort; /* List of buckets we're currently writing data to */ struct list_head data_buckets; spinlock_t data_bucket_lock; struct journal journal; #define CONGESTED_MAX 1024 unsigned int congested_last_us; atomic_t congested; /* The rest of this all shows up in sysfs */ unsigned int congested_read_threshold_us; unsigned int congested_write_threshold_us; struct time_stats btree_gc_time; struct time_stats btree_split_time; struct time_stats btree_read_time; atomic_long_t cache_read_races; atomic_long_t writeback_keys_done; atomic_long_t writeback_keys_failed; atomic_long_t reclaim; atomic_long_t reclaimed_journal_buckets; atomic_long_t flush_write; enum { ON_ERROR_UNREGISTER, ON_ERROR_PANIC, } on_error; #define DEFAULT_IO_ERROR_LIMIT 8 unsigned int error_limit; unsigned int error_decay; unsigned short journal_delay_ms; bool expensive_debug_checks; unsigned int verify:1; unsigned int key_merging_disabled:1; unsigned int gc_always_rewrite:1; unsigned int shrinker_disabled:1; unsigned int copy_gc_enabled:1; unsigned int idle_max_writeback_rate_enabled:1; #define BUCKET_HASH_BITS 12 struct hlist_head bucket_hash[1 << BUCKET_HASH_BITS]; }; struct bbio { unsigned int submit_time_us; union { struct bkey key; uint64_t _pad[3]; /* * We only need pad = 3 here because we only ever carry around a * single pointer - i.e. the pointer we're doing io to/from. */ }; struct bio bio; }; #define BTREE_PRIO USHRT_MAX #define INITIAL_PRIO 32768U #define btree_bytes(c) ((c)->btree_pages * PAGE_SIZE) #define btree_blocks(b) \ ((unsigned int) (KEY_SIZE(&b->key) >> (b)->c->block_bits)) #define btree_default_blocks(c) \ ((unsigned int) ((PAGE_SECTORS * (c)->btree_pages) >> (c)->block_bits)) #define bucket_bytes(ca) ((ca)->sb.bucket_size << 9) #define block_bytes(ca) ((ca)->sb.block_size << 9) static inline unsigned int meta_bucket_pages(struct cache_sb *sb) { unsigned int n, max_pages; max_pages = min_t(unsigned int, __rounddown_pow_of_two(USHRT_MAX) / PAGE_SECTORS, MAX_ORDER_NR_PAGES); n = sb->bucket_size / PAGE_SECTORS; if (n > max_pages) n = max_pages; return n; } static inline unsigned int meta_bucket_bytes(struct cache_sb *sb) { return meta_bucket_pages(sb) << PAGE_SHIFT; } #define prios_per_bucket(ca) \ ((meta_bucket_bytes(&(ca)->sb) - sizeof(struct prio_set)) / \ sizeof(struct bucket_disk)) #define prio_buckets(ca) \ DIV_ROUND_UP((size_t) (ca)->sb.nbuckets, prios_per_bucket(ca)) static inline size_t sector_to_bucket(struct cache_set *c, sector_t s) { return s >> c->bucket_bits; } static inline sector_t bucket_to_sector(struct cache_set *c, size_t b) { return ((sector_t) b) << c->bucket_bits; } static inline sector_t bucket_remainder(struct cache_set *c, sector_t s) { return s & (c->cache->sb.bucket_size - 1); } static inline struct cache *PTR_CACHE(struct cache_set *c, const struct bkey *k, unsigned int ptr) { return c->cache; } static inline size_t PTR_BUCKET_NR(struct cache_set *c, const struct bkey *k, unsigned int ptr) { return sector_to_bucket(c, PTR_OFFSET(k, ptr)); } static inline struct bucket *PTR_BUCKET(struct cache_set *c, const struct bkey *k, unsigned int ptr) { return PTR_CACHE(c, k, ptr)->buckets + PTR_BUCKET_NR(c, k, ptr); } static inline uint8_t gen_after(uint8_t a, uint8_t b) { uint8_t r = a - b; return r > 128U ? 0 : r; } static inline uint8_t ptr_stale(struct cache_set *c, const struct bkey *k, unsigned int i) { return gen_after(PTR_BUCKET(c, k, i)->gen, PTR_GEN(k, i)); } static inline bool ptr_available(struct cache_set *c, const struct bkey *k, unsigned int i) { return (PTR_DEV(k, i) < MAX_CACHES_PER_SET) && PTR_CACHE(c, k, i); } /* Btree key macros */ /* * This is used for various on disk data structures - cache_sb, prio_set, bset, * jset: The checksum is _always_ the first 8 bytes of these structs */ #define csum_set(i) \ bch_crc64(((void *) (i)) + sizeof(uint64_t), \ ((void *) bset_bkey_last(i)) - \ (((void *) (i)) + sizeof(uint64_t))) /* Error handling macros */ #define btree_bug(b, ...) \ do { \ if (bch_cache_set_error((b)->c, __VA_ARGS__)) \ dump_stack(); \ } while (0) #define cache_bug(c, ...) \ do { \ if (bch_cache_set_error(c, __VA_ARGS__)) \ dump_stack(); \ } while (0) #define btree_bug_on(cond, b, ...) \ do { \ if (cond) \ btree_bug(b, __VA_ARGS__); \ } while (0) #define cache_bug_on(cond, c, ...) \ do { \ if (cond) \ cache_bug(c, __VA_ARGS__); \ } while (0) #define cache_set_err_on(cond, c, ...) \ do { \ if (cond) \ bch_cache_set_error(c, __VA_ARGS__); \ } while (0) /* Looping macros */ #define for_each_bucket(b, ca) \ for (b = (ca)->buckets + (ca)->sb.first_bucket; \ b < (ca)->buckets + (ca)->sb.nbuckets; b++) static inline void cached_dev_put(struct cached_dev *dc) { if (refcount_dec_and_test(&dc->count)) schedule_work(&dc->detach); } static inline bool cached_dev_get(struct cached_dev *dc) { if (!refcount_inc_not_zero(&dc->count)) return false; /* Paired with the mb in cached_dev_attach */ smp_mb__after_atomic(); return true; } /* * bucket_gc_gen() returns the difference between the bucket's current gen and * the oldest gen of any pointer into that bucket in the btree (last_gc). */ static inline uint8_t bucket_gc_gen(struct bucket *b) { return b->gen - b->last_gc; } #define BUCKET_GC_GEN_MAX 96U #define kobj_attribute_write(n, fn) \ static struct kobj_attribute ksysfs_##n = __ATTR(n, 0200, NULL, fn) #define kobj_attribute_rw(n, show, store) \ static struct kobj_attribute ksysfs_##n = \ __ATTR(n, 0600, show, store) static inline void wake_up_allocators(struct cache_set *c) { struct cache *ca = c->cache; wake_up_process(ca->alloc_thread); } static inline void closure_bio_submit(struct cache_set *c, struct bio *bio, struct closure *cl) { closure_get(cl); if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags))) { bio->bi_status = BLK_STS_IOERR; bio_endio(bio); return; } submit_bio_noacct(bio); } /* * Prevent the kthread exits directly, and make sure when kthread_stop() * is called to stop a kthread, it is still alive. If a kthread might be * stopped by CACHE_SET_IO_DISABLE bit set, wait_for_kthread_stop() is * necessary before the kthread returns. */ static inline void wait_for_kthread_stop(void) { while (!kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); schedule(); } } /* Forward declarations */ void bch_count_backing_io_errors(struct cached_dev *dc, struct bio *bio); void bch_count_io_errors(struct cache *ca, blk_status_t error, int is_read, const char *m); void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, blk_status_t error, const char *m); void bch_bbio_endio(struct cache_set *c, struct bio *bio, blk_status_t error, const char *m); void bch_bbio_free(struct bio *bio, struct cache_set *c); struct bio *bch_bbio_alloc(struct cache_set *c); void __bch_submit_bbio(struct bio *bio, struct cache_set *c); void bch_submit_bbio(struct bio *bio, struct cache_set *c, struct bkey *k, unsigned int ptr); uint8_t bch_inc_gen(struct cache *ca, struct bucket *b); void bch_rescale_priorities(struct cache_set *c, int sectors); bool bch_can_invalidate_bucket(struct cache *ca, struct bucket *b); void __bch_invalidate_one_bucket(struct cache *ca, struct bucket *b); void __bch_bucket_free(struct cache *ca, struct bucket *b); void bch_bucket_free(struct cache_set *c, struct bkey *k); long bch_bucket_alloc(struct cache *ca, unsigned int reserve, bool wait); int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve, struct bkey *k, bool wait); int bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve, struct bkey *k, bool wait); bool bch_alloc_sectors(struct cache_set *c, struct bkey *k, unsigned int sectors, unsigned int write_point, unsigned int write_prio, bool wait); bool bch_cached_dev_error(struct cached_dev *dc); __printf(2, 3) bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...); int bch_prio_write(struct cache *ca, bool wait); void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent); extern struct workqueue_struct *bcache_wq; extern struct workqueue_struct *bch_journal_wq; extern struct workqueue_struct *bch_flush_wq; extern struct mutex bch_register_lock; extern struct list_head bch_cache_sets; extern struct kobj_type bch_cached_dev_ktype; extern struct kobj_type bch_flash_dev_ktype; extern struct kobj_type bch_cache_set_ktype; extern struct kobj_type bch_cache_set_internal_ktype; extern struct kobj_type bch_cache_ktype; void bch_cached_dev_release(struct kobject *kobj); void bch_flash_dev_release(struct kobject *kobj); void bch_cache_set_release(struct kobject *kobj); void bch_cache_release(struct kobject *kobj); int bch_uuid_write(struct cache_set *c); void bcache_write_super(struct cache_set *c); int bch_flash_dev_create(struct cache_set *c, uint64_t size); int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c, uint8_t *set_uuid); void bch_cached_dev_detach(struct cached_dev *dc); int bch_cached_dev_run(struct cached_dev *dc); void bcache_device_stop(struct bcache_device *d); void bch_cache_set_unregister(struct cache_set *c); void bch_cache_set_stop(struct cache_set *c); struct cache_set *bch_cache_set_alloc(struct cache_sb *sb); void bch_btree_cache_free(struct cache_set *c); int bch_btree_cache_alloc(struct cache_set *c); void bch_moving_init_cache_set(struct cache_set *c); int bch_open_buckets_alloc(struct cache_set *c); void bch_open_buckets_free(struct cache_set *c); int bch_cache_allocator_start(struct cache *ca); void bch_debug_exit(void); void bch_debug_init(void); void bch_request_exit(void); int bch_request_init(void); void bch_btree_exit(void); int bch_btree_init(void); #endif /* _BCACHE_H */