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Diffstat (limited to 'fs/bcachefs/alloc.c')
| -rw-r--r-- | fs/bcachefs/alloc.c | 2205 |
1 files changed, 2205 insertions, 0 deletions
diff --git a/fs/bcachefs/alloc.c b/fs/bcachefs/alloc.c new file mode 100644 index 000000000000..e6e506e4a8a3 --- /dev/null +++ b/fs/bcachefs/alloc.c @@ -0,0 +1,2205 @@ +/* + * Primary bucket allocation code + * + * Copyright 2012 Google, Inc. + * + * Allocation in bcache is done in terms of buckets: + * + * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in + * btree pointers - they must match for the pointer to be considered valid. + * + * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a + * bucket simply by incrementing its gen. + * + * The gens (along with the priorities; it's really the gens are important but + * the code is named as if it's the priorities) are written in an arbitrary list + * of buckets on disk, with a pointer to them in the journal header. + * + * When we invalidate a bucket, we have to write its new gen to disk and wait + * for that write to complete before we use it - otherwise after a crash we + * could have pointers that appeared to be good but pointed to data that had + * been overwritten. + * + * Since the gens and priorities are all stored contiguously on disk, we can + * batch this up: We fill up the free_inc list with freshly invalidated buckets, + * call prio_write(), and when prio_write() finishes we pull buckets off the + * free_inc list and optionally discard them. + * + * free_inc isn't the only freelist - if it was, we'd often have to sleep while + * priorities and gens were being written before we could allocate. c->free is a + * smaller freelist, and buckets on that list are always ready to be used. + * + * If we've got discards enabled, that happens when a bucket moves from the + * free_inc list to the free list. + * + * It's important to ensure that gens don't wrap around - with respect to + * either the oldest gen in the btree or the gen on disk. This is quite + * difficult to do in practice, but we explicitly guard against it anyways - if + * a bucket is in danger of wrapping around we simply skip invalidating it that + * time around, and we garbage collect or rewrite the priorities sooner than we + * would have otherwise. + * + * bch2_bucket_alloc() allocates a single bucket from a specific device. + * + * bch2_bucket_alloc_set() allocates one or more buckets from different devices + * in a given filesystem. + * + * invalidate_buckets() drives all the processes described above. It's called + * from bch2_bucket_alloc() and a few other places that need to make sure free + * buckets are ready. + * + * invalidate_buckets_(lru|fifo)() find buckets that are available to be + * invalidated, and then invalidate them and stick them on the free_inc list - + * in either lru or fifo order. + */ + +#include "bcachefs.h" +#include "alloc.h" +#include "btree_cache.h" +#include "btree_io.h" +#include "btree_update.h" +#include "btree_update_interior.h" +#include "btree_gc.h" +#include "buckets.h" +#include "checksum.h" +#include "clock.h" +#include "debug.h" +#include "disk_groups.h" +#include "error.h" +#include "extents.h" +#include "io.h" +#include "journal.h" +#include "journal_io.h" +#include "super-io.h" +#include "trace.h" + +#include <linux/blkdev.h> +#include <linux/kthread.h> +#include <linux/math64.h> +#include <linux/random.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> +#include <linux/sched/task.h> +#include <linux/sort.h> + +static void bch2_recalc_oldest_io(struct bch_fs *, struct bch_dev *, int); + +/* Ratelimiting/PD controllers */ + +static void pd_controllers_update(struct work_struct *work) +{ + struct bch_fs *c = container_of(to_delayed_work(work), + struct bch_fs, + pd_controllers_update); + struct bch_dev *ca; + unsigned i; + + for_each_member_device(ca, c, i) { + struct bch_dev_usage stats = bch2_dev_usage_read(c, ca); + + u64 free = bucket_to_sector(ca, + __dev_buckets_free(ca, stats)) << 9; + /* + * Bytes of internal fragmentation, which can be + * reclaimed by copy GC + */ + s64 fragmented = (bucket_to_sector(ca, + stats.buckets[BCH_DATA_USER] + + stats.buckets[BCH_DATA_CACHED]) - + (stats.sectors[BCH_DATA_USER] + + stats.sectors[BCH_DATA_CACHED])) << 9; + + fragmented = max(0LL, fragmented); + + bch2_pd_controller_update(&ca->copygc_pd, + free, fragmented, -1); + } + + schedule_delayed_work(&c->pd_controllers_update, + c->pd_controllers_update_seconds * HZ); +} + +/* Persistent alloc info: */ + +static unsigned bch_alloc_val_u64s(const struct bch_alloc *a) +{ + unsigned bytes = offsetof(struct bch_alloc, data); + + if (a->fields & (1 << BCH_ALLOC_FIELD_READ_TIME)) + bytes += 2; + if (a->fields & (1 << BCH_ALLOC_FIELD_WRITE_TIME)) + bytes += 2; + + return DIV_ROUND_UP(bytes, sizeof(u64)); +} + +const char *bch2_alloc_invalid(const struct bch_fs *c, struct bkey_s_c k) +{ + if (k.k->p.inode >= c->sb.nr_devices || + !c->devs[k.k->p.inode]) + return "invalid device"; + + switch (k.k->type) { + case BCH_ALLOC: { + struct bkey_s_c_alloc a = bkey_s_c_to_alloc(k); + + if (bch_alloc_val_u64s(a.v) != bkey_val_u64s(a.k)) + return "incorrect value size"; + break; + } + default: + return "invalid type"; + } + + return NULL; +} + +void bch2_alloc_to_text(struct bch_fs *c, char *buf, + size_t size, struct bkey_s_c k) +{ + buf[0] = '\0'; + + switch (k.k->type) { + case BCH_ALLOC: + break; + } +} + +static inline unsigned get_alloc_field(const u8 **p, unsigned bytes) +{ + unsigned v; + + switch (bytes) { + case 1: + v = **p; + break; + case 2: + v = le16_to_cpup((void *) *p); + break; + case 4: + v = le32_to_cpup((void *) *p); + break; + default: + BUG(); + } + + *p += bytes; + return v; +} + +static inline void put_alloc_field(u8 **p, unsigned bytes, unsigned v) +{ + switch (bytes) { + case 1: + **p = v; + break; + case 2: + *((__le16 *) *p) = cpu_to_le16(v); + break; + case 4: + *((__le32 *) *p) = cpu_to_le32(v); + break; + default: + BUG(); + } + + *p += bytes; +} + +static void bch2_alloc_read_key(struct bch_fs *c, struct bkey_s_c k) +{ + struct bch_dev *ca; + struct bkey_s_c_alloc a; + struct bucket_mark new; + struct bucket *g; + const u8 *d; + + if (k.k->type != BCH_ALLOC) + return; + + a = bkey_s_c_to_alloc(k); + ca = bch_dev_bkey_exists(c, a.k->p.inode); + + if (a.k->p.offset >= ca->mi.nbuckets) + return; + + percpu_down_read(&c->usage_lock); + + g = bucket(ca, a.k->p.offset); + bucket_cmpxchg(g, new, ({ + new.gen = a.v->gen; + new.gen_valid = 1; + })); + + d = a.v->data; + if (a.v->fields & (1 << BCH_ALLOC_FIELD_READ_TIME)) + g->io_time[READ] = get_alloc_field(&d, 2); + if (a.v->fields & (1 << BCH_ALLOC_FIELD_WRITE_TIME)) + g->io_time[WRITE] = get_alloc_field(&d, 2); + + percpu_up_read(&c->usage_lock); +} + +int bch2_alloc_read(struct bch_fs *c, struct list_head *journal_replay_list) +{ + struct journal_replay *r; + struct btree_iter iter; + struct bkey_s_c k; + struct bch_dev *ca; + unsigned i; + int ret; + + for_each_btree_key(&iter, c, BTREE_ID_ALLOC, POS_MIN, 0, k) { + bch2_alloc_read_key(c, k); + bch2_btree_iter_cond_resched(&iter); + } + + ret = bch2_btree_iter_unlock(&iter); + if (ret) + return ret; + + list_for_each_entry(r, journal_replay_list, list) { + struct bkey_i *k, *n; + struct jset_entry *entry; + + for_each_jset_key(k, n, entry, &r->j) + if (entry->btree_id == BTREE_ID_ALLOC) + bch2_alloc_read_key(c, bkey_i_to_s_c(k)); + } + + mutex_lock(&c->bucket_clock[READ].lock); + for_each_member_device(ca, c, i) { + down_read(&ca->bucket_lock); + bch2_recalc_oldest_io(c, ca, READ); + up_read(&ca->bucket_lock); + } + mutex_unlock(&c->bucket_clock[READ].lock); + + mutex_lock(&c->bucket_clock[WRITE].lock); + for_each_member_device(ca, c, i) { + down_read(&ca->bucket_lock); + bch2_recalc_oldest_io(c, ca, WRITE); + up_read(&ca->bucket_lock); + } + mutex_unlock(&c->bucket_clock[WRITE].lock); + + return 0; +} + +static int __bch2_alloc_write_key(struct bch_fs *c, struct bch_dev *ca, + size_t b, struct btree_iter *iter, + u64 *journal_seq, bool nowait) +{ + struct bucket_mark m; + __BKEY_PADDED(k, DIV_ROUND_UP(sizeof(struct bch_alloc), 8)) alloc_key; + struct bucket *g; + struct bkey_i_alloc *a; + u8 *d; + int ret; + unsigned flags = BTREE_INSERT_ATOMIC| + BTREE_INSERT_NOFAIL| + BTREE_INSERT_USE_RESERVE| + BTREE_INSERT_USE_ALLOC_RESERVE; + + if (nowait) + flags |= BTREE_INSERT_NOWAIT; + + bch2_btree_iter_set_pos(iter, POS(ca->dev_idx, b)); + + do { + ret = btree_iter_err(bch2_btree_iter_peek_slot(iter)); + if (ret) + break; + + percpu_down_read(&c->usage_lock); + g = bucket(ca, b); + + /* read mark under btree node lock: */ + m = READ_ONCE(g->mark); + a = bkey_alloc_init(&alloc_key.k); + a->k.p = iter->pos; + a->v.fields = 0; + a->v.gen = m.gen; + set_bkey_val_u64s(&a->k, bch_alloc_val_u64s(&a->v)); + + d = a->v.data; + if (a->v.fields & (1 << BCH_ALLOC_FIELD_READ_TIME)) + put_alloc_field(&d, 2, g->io_time[READ]); + if (a->v.fields & (1 << BCH_ALLOC_FIELD_WRITE_TIME)) + put_alloc_field(&d, 2, g->io_time[WRITE]); + percpu_up_read(&c->usage_lock); + + ret = bch2_btree_insert_at(c, NULL, NULL, journal_seq, flags, + BTREE_INSERT_ENTRY(iter, &a->k_i)); + bch2_btree_iter_cond_resched(iter); + } while (ret == -EINTR); + + return ret; +} + +int bch2_alloc_replay_key(struct bch_fs *c, struct bpos pos) +{ + struct bch_dev *ca; + struct btree_iter iter; + int ret; + + if (pos.inode >= c->sb.nr_devices || !c->devs[pos.inode]) + return 0; + + ca = bch_dev_bkey_exists(c, pos.inode); + + if (pos.offset >= ca->mi.nbuckets) + return 0; + + bch2_btree_iter_init(&iter, c, BTREE_ID_ALLOC, POS_MIN, + BTREE_ITER_SLOTS|BTREE_ITER_INTENT); + + ret = __bch2_alloc_write_key(c, ca, pos.offset, &iter, + NULL, false); + bch2_btree_iter_unlock(&iter); + return ret; +} + +int bch2_alloc_write(struct bch_fs *c) +{ + struct bch_dev *ca; + unsigned i; + int ret = 0; + + for_each_rw_member(ca, c, i) { + struct btree_iter iter; + unsigned long bucket; + + bch2_btree_iter_init(&iter, c, BTREE_ID_ALLOC, POS_MIN, + BTREE_ITER_SLOTS|BTREE_ITER_INTENT); + + down_read(&ca->bucket_lock); + for_each_set_bit(bucket, ca->buckets_dirty, ca->mi.nbuckets) { + ret = __bch2_alloc_write_key(c, ca, bucket, &iter, + NULL, false); + if (ret) + break; + + clear_bit(bucket, ca->buckets_dirty); + } + up_read(&ca->bucket_lock); + bch2_btree_iter_unlock(&iter); + + if (ret) { + percpu_ref_put(&ca->io_ref); + break; + } + } + + return ret; +} + +/* Bucket IO clocks: */ + +static void bch2_recalc_oldest_io(struct bch_fs *c, struct bch_dev *ca, int rw) +{ + struct bucket_clock *clock = &c->bucket_clock[rw]; + struct bucket_array *buckets = bucket_array(ca); + struct bucket *g; + u16 max_last_io = 0; + unsigned i; + + lockdep_assert_held(&c->bucket_clock[rw].lock); + + /* Recalculate max_last_io for this device: */ + for_each_bucket(g, buckets) + max_last_io = max(max_last_io, bucket_last_io(c, g, rw)); + + ca->max_last_bucket_io[rw] = max_last_io; + + /* Recalculate global max_last_io: */ + max_last_io = 0; + + for_each_member_device(ca, c, i) + max_last_io = max(max_last_io, ca->max_last_bucket_io[rw]); + + clock->max_last_io = max_last_io; +} + +static void bch2_rescale_bucket_io_times(struct bch_fs *c, int rw) +{ + struct bucket_clock *clock = &c->bucket_clock[rw]; + struct bucket_array *buckets; + struct bch_dev *ca; + struct bucket *g; + unsigned i; + + trace_rescale_prios(c); + + for_each_member_device(ca, c, i) { + down_read(&ca->bucket_lock); + buckets = bucket_array(ca); + + for_each_bucket(g, buckets) + g->io_time[rw] = clock->hand - + bucket_last_io(c, g, rw) / 2; + + bch2_recalc_oldest_io(c, ca, rw); + + up_read(&ca->bucket_lock); + } +} + +static void bch2_inc_clock_hand(struct io_timer *timer) +{ + struct bucket_clock *clock = container_of(timer, + struct bucket_clock, rescale); + struct bch_fs *c = container_of(clock, + struct bch_fs, bucket_clock[clock->rw]); + struct bch_dev *ca; + u64 capacity; + unsigned i; + + mutex_lock(&clock->lock); + + /* if clock cannot be advanced more, rescale prio */ + if (clock->max_last_io >= U16_MAX - 2) + bch2_rescale_bucket_io_times(c, clock->rw); + + BUG_ON(clock->max_last_io >= U16_MAX - 2); + + for_each_member_device(ca, c, i) + ca->max_last_bucket_io[clock->rw]++; + clock->max_last_io++; + clock->hand++; + + mutex_unlock(&clock->lock); + + capacity = READ_ONCE(c->capacity); + + if (!capacity) + return; + + /* + * we only increment when 0.1% of the filesystem capacity has been read + * or written too, this determines if it's time + * + * XXX: we shouldn't really be going off of the capacity of devices in + * RW mode (that will be 0 when we're RO, yet we can still service + * reads) + */ + timer->expire += capacity >> 10; + + bch2_io_timer_add(&c->io_clock[clock->rw], timer); +} + +static void bch2_bucket_clock_init(struct bch_fs *c, int rw) +{ + struct bucket_clock *clock = &c->bucket_clock[rw]; + + clock->hand = 1; + clock->rw = rw; + clock->rescale.fn = bch2_inc_clock_hand; + clock->rescale.expire = c->capacity >> 10; + mutex_init(&clock->lock); +} + +/* Background allocator thread: */ + +/* + * Scans for buckets to be invalidated, invalidates them, rewrites prios/gens + * (marking them as invalidated on disk), then optionally issues discard + * commands to the newly free buckets, then puts them on the various freelists. + */ + +static void verify_not_on_freelist(struct bch_fs *c, struct bch_dev *ca, + size_t bucket) +{ + if (expensive_debug_checks(c) && + test_bit(BCH_FS_ALLOCATOR_STARTED, &c->flags)) { + size_t iter; + long i; + unsigned j; + + for (j = 0; j < RESERVE_NR; j++) + fifo_for_each_entry(i, &ca->free[j], iter) + BUG_ON(i == bucket); + fifo_for_each_entry(i, &ca->free_inc, iter) + BUG_ON(i == bucket); + } +} + +#define BUCKET_GC_GEN_MAX 96U + +/** + * wait_buckets_available - wait on reclaimable buckets + * + * If there aren't enough available buckets to fill up free_inc, wait until + * there are. + */ +static int wait_buckets_available(struct bch_fs *c, struct bch_dev *ca) +{ + unsigned long gc_count = c->gc_count; + int ret = 0; + + while (1) { + set_current_state(TASK_INTERRUPTIBLE); + if (kthread_should_stop()) { + ret = 1; + break; + } + + if (gc_count != c->gc_count) + ca->inc_gen_really_needs_gc = 0; + + if ((ssize_t) (dev_buckets_available(c, ca) - + ca->inc_gen_really_needs_gc) >= + (ssize_t) fifo_free(&ca->free_inc)) + break; + + up_read(&c->gc_lock); + schedule(); + try_to_freeze(); + down_read(&c->gc_lock); + } + + __set_current_state(TASK_RUNNING); + return ret; +} + +static bool bch2_can_invalidate_bucket(struct bch_dev *ca, + size_t bucket, + struct bucket_mark mark) +{ + u8 gc_gen; + + if (!is_available_bucket(mark)) + return false; + + gc_gen = bucket_gc_gen(ca, bucket); + + if (gc_gen >= BUCKET_GC_GEN_MAX / 2) + ca->inc_gen_needs_gc++; + + if (gc_gen >= BUCKET_GC_GEN_MAX) + ca->inc_gen_really_needs_gc++; + + return gc_gen < BUCKET_GC_GEN_MAX; +} + +static void bch2_invalidate_one_bucket(struct bch_fs *c, struct bch_dev *ca, + size_t bucket) +{ + struct bucket_mark m; + + percpu_down_read(&c->usage_lock); + spin_lock(&c->freelist_lock); + + if (!bch2_invalidate_bucket(c, ca, bucket, &m)) { + spin_unlock(&c->freelist_lock); + percpu_up_read(&c->usage_lock); + return; + } + + verify_not_on_freelist(c, ca, bucket); + BUG_ON(!fifo_push(&ca->free_inc, bucket)); + + spin_unlock(&c->freelist_lock); + percpu_up_read(&c->usage_lock); + + /* gc lock held: */ + bucket_io_clock_reset(c, ca, bucket, READ); + bucket_io_clock_reset(c, ca, bucket, WRITE); + + if (m.cached_sectors) { + ca->allocator_invalidating_data = true; + } else if (m.journal_seq_valid) { + u64 journal_seq = atomic64_read(&c->journal.seq); + u64 bucket_seq = journal_seq; + + bucket_seq &= ~((u64) U16_MAX); + bucket_seq |= m.journal_seq; + + if (bucket_seq > journal_seq) + bucket_seq -= 1 << 16; + + ca->allocator_journal_seq_flush = + max(ca->allocator_journal_seq_flush, bucket_seq); + } +} + +/* + * Determines what order we're going to reuse buckets, smallest bucket_key() + * first. + * + * + * - We take into account the read prio of the bucket, which gives us an + * indication of how hot the data is -- we scale the prio so that the prio + * farthest from the clock is worth 1/8th of the closest. + * + * - The number of sectors of cached data in the bucket, which gives us an + * indication of the cost in cache misses this eviction will cause. + * + * - If hotness * sectors used compares equal, we pick the bucket with the + * smallest bucket_gc_gen() - since incrementing the same bucket's generation + * number repeatedly forces us to run mark and sweep gc to avoid generation + * number wraparound. + */ + +static unsigned long bucket_sort_key(struct bch_fs *c, struct bch_dev *ca, + size_t b, struct bucket_mark m) +{ + unsigned last_io = bucket_last_io(c, bucket(ca, b), READ); + unsigned max_last_io = ca->max_last_bucket_io[READ]; + + /* + * Time since last read, scaled to [0, 8) where larger value indicates + * more recently read data: + */ + unsigned long hotness = (max_last_io - last_io) * 7 / max_last_io; + + /* How much we want to keep the data in this bucket: */ + unsigned long data_wantness = + (hotness + 1) * bucket_sectors_used(m); + + unsigned long needs_journal_commit = + bucket_needs_journal_commit(m, c->journal.last_seq_ondisk); + + return (data_wantness << 9) | + (needs_journal_commit << 8) | + bucket_gc_gen(ca, b); +} + +static inline int bucket_alloc_cmp(alloc_heap *h, + struct alloc_heap_entry l, + struct alloc_heap_entry r) +{ + return (l.key > r.key) - (l.key < r.key) ?: + (l.nr < r.nr) - (l.nr > r.nr) ?: + (l.bucket > r.bucket) - (l.bucket < r.bucket); +} + +static void find_reclaimable_buckets_lru(struct bch_fs *c, struct bch_dev *ca) +{ + struct bucket_array *buckets; + struct alloc_heap_entry e = { 0 }; + size_t b; + + ca->alloc_heap.used = 0; + + mutex_lock(&c->bucket_clock[READ].lock); + down_read(&ca->bucket_lock); + + buckets = bucket_array(ca); + + bch2_recalc_oldest_io(c, ca, READ); + + /* + * Find buckets with lowest read priority, by building a maxheap sorted + * by read priority and repeatedly replacing the maximum element until + * all buckets have been visited. + */ + for (b = ca->mi.first_bucket; b < ca->mi.nbuckets; b++) { + struct bucket_mark m = READ_ONCE(buckets->b[b].mark); + unsigned long key = bucket_sort_key(c, ca, b, m); + + if (!bch2_can_invalidate_bucket(ca, b, m)) + continue; + + if (e.nr && e.bucket + e.nr == b && e.key == key) { + e.nr++; + } else { + if (e.nr) + heap_add_or_replace(&ca->alloc_heap, e, -bucket_alloc_cmp); + + e = (struct alloc_heap_entry) { + .bucket = b, + .nr = 1, + .key = key, + }; + } + + cond_resched(); + } + + if (e.nr) + heap_add_or_replace(&ca->alloc_heap, e, -bucket_alloc_cmp); + + up_read(&ca->bucket_lock); + mutex_unlock(&c->bucket_clock[READ].lock); + + heap_resort(&ca->alloc_heap, bucket_alloc_cmp); + + while (heap_pop(&ca->alloc_heap, e, bucket_alloc_cmp)) { + for (b = e.bucket; + b < e.bucket + e.nr; + b++) { + if (fifo_full(&ca->free_inc)) + return; + + bch2_invalidate_one_bucket(c, ca, b); + } + } +} + +static void find_reclaimable_buckets_fifo(struct bch_fs *c, struct bch_dev *ca) +{ + struct bucket_array *buckets = bucket_array(ca); + struct bucket_mark m; + size_t b, checked; + + for (checked = 0; + checked < ca->mi.nbuckets && !fifo_full(&ca->free_inc); + checked++) { + if (ca->fifo_last_bucket < ca->mi.first_bucket || + ca->fifo_last_bucket >= ca->mi.nbuckets) + ca->fifo_last_bucket = ca->mi.first_bucket; + + b = ca->fifo_last_bucket++; + + m = READ_ONCE(buckets->b[b].mark); + + if (bch2_can_invalidate_bucket(ca, b, m)) + bch2_invalidate_one_bucket(c, ca, b); + + cond_resched(); + } +} + +static void find_reclaimable_buckets_random(struct bch_fs *c, struct bch_dev *ca) +{ + struct bucket_array *buckets = bucket_array(ca); + struct bucket_mark m; + size_t checked; + + for (checked = 0; + checked < ca->mi.nbuckets / 2 && !fifo_full(&ca->free_inc); + checked++) { + size_t b = bch2_rand_range(ca->mi.nbuckets - + ca->mi.first_bucket) + + ca->mi.first_bucket; + + m = READ_ONCE(buckets->b[b].mark); + + if (bch2_can_invalidate_bucket(ca, b, m)) + bch2_invalidate_one_bucket(c, ca, b); + + cond_resched(); + } +} + +static void find_reclaimable_buckets(struct bch_fs *c, struct bch_dev *ca) +{ + ca->inc_gen_needs_gc = 0; + ca->inc_gen_really_needs_gc = 0; + + switch (ca->mi.replacement) { + case CACHE_REPLACEMENT_LRU: + find_reclaimable_buckets_lru(c, ca); + break; + case CACHE_REPLACEMENT_FIFO: + find_reclaimable_buckets_fifo(c, ca); + break; + case CACHE_REPLACEMENT_RANDOM: + find_reclaimable_buckets_random(c, ca); + break; + } +} + +static int size_t_cmp(const void *_l, const void *_r) +{ + const size_t *l = _l, *r = _r; + + return (*l > *r) - (*l < *r); +} + +static void sort_free_inc(struct bch_fs *c, struct bch_dev *ca) +{ + BUG_ON(ca->free_inc.front); + + spin_lock(&c->freelist_lock); + sort(ca->free_inc.data, + ca->free_inc.back, + sizeof(ca->free_inc.data[0]), + size_t_cmp, NULL); + spin_unlock(&c->freelist_lock); +} + +static int bch2_invalidate_free_inc(struct bch_fs *c, struct bch_dev *ca, + u64 *journal_seq, size_t nr, + bool nowait) +{ + struct btree_iter iter; + int ret = 0; + + bch2_btree_iter_init(&iter, c, BTREE_ID_ALLOC, POS(ca->dev_idx, 0), + BTREE_ITER_SLOTS|BTREE_ITER_INTENT); + + /* Only use nowait if we've already invalidated at least one bucket: */ + while (ca->nr_invalidated < min(nr, fifo_used(&ca->free_inc))) { + size_t b = fifo_idx_entry(&ca->free_inc, ca->nr_invalidated); + + ret = __bch2_alloc_write_key(c, ca, b, &iter, journal_seq, + nowait && ca->nr_invalidated); + if (ret) + break; + + ca->nr_invalidated++; + } + + bch2_btree_iter_unlock(&iter); + + /* If we used NOWAIT, don't return the error: */ + return ca->nr_invalidated ? 0 : ret; +} + +static bool __push_invalidated_bucket(struct bch_fs *c, struct bch_dev *ca, size_t bucket) +{ + unsigned i; + + /* + * Don't remove from free_inc until after it's added to + * freelist, so gc can find it: + */ + spin_lock(&c->freelist_lock); + for (i = 0; i < RESERVE_NR; i++) + if (fifo_push(&ca->free[i], bucket)) { + fifo_pop(&ca->free_inc, bucket); + --ca->nr_invalidated; + closure_wake_up(&c->freelist_wait); + spin_unlock(&c->freelist_lock); + return true; + } + spin_unlock(&c->freelist_lock); + + return false; +} + +static int push_invalidated_bucket(struct bch_fs *c, struct bch_dev *ca, size_t bucket) +{ + int ret = 0; + + while (1) { + set_current_state(TASK_INTERRUPTIBLE); + + if (__push_invalidated_bucket(c, ca, bucket)) + break; + + if ((current->flags & PF_KTHREAD) && + kthread_should_stop()) { + ret = 1; + break; + } + + schedule(); + try_to_freeze(); + } + + __set_current_state(TASK_RUNNING); + return ret; +} + +/* + * Given an invalidated, ready to use bucket: issue a discard to it if enabled, + * then add it to the freelist, waiting until there's room if necessary: + */ +static int discard_invalidated_buckets(struct bch_fs *c, struct bch_dev *ca) +{ + while (ca->nr_invalidated) { + size_t bucket = fifo_peek(&ca->free_inc); + + BUG_ON(fifo_empty(&ca->free_inc) || !ca->nr_invalidated); + + if (ca->mi.discard && + bdev_max_discard_sectors(ca->disk_sb.bdev)) + blkdev_issue_discard(ca->disk_sb.bdev, + bucket_to_sector(ca, bucket), + ca->mi.bucket_size, GFP_NOIO); + + if (push_invalidated_bucket(c, ca, bucket)) + return 1; + } + + return 0; +} + +/** + * bch_allocator_thread - move buckets from free_inc to reserves + * + * The free_inc FIFO is populated by find_reclaimable_buckets(), and + * the reserves are depleted by bucket allocation. When we run out + * of free_inc, try to invalidate some buckets and write out + * prios and gens. + */ +static int bch2_allocator_thread(void *arg) +{ + struct bch_dev *ca = arg; + struct bch_fs *c = ca->fs; + u64 journal_seq; + int ret; + + set_freezable(); + + while (1) { + while (1) { + cond_resched(); + + pr_debug("discarding %zu invalidated buckets", + ca->nr_invalidated); + + ret = discard_invalidated_buckets(c, ca); + if (ret) + goto stop; + + if (fifo_empty(&ca->free_inc)) + break; + + pr_debug("invalidating %zu buckets", + fifo_used(&ca->free_inc)); + + journal_seq = 0; + ret = bch2_invalidate_free_inc(c, ca, &journal_seq, + SIZE_MAX, true); + if (ret) { + bch_err(ca, "error invalidating buckets: %i", ret); + goto stop; + } + + if (!ca->nr_invalidated) { + bch_err(ca, "allocator thread unable to make forward progress!"); + goto stop; + } + + if (ca->allocator_invalidating_data) + ret = bch2_journal_flush_seq(&c->journal, journal_seq); + else if (ca->allocator_journal_seq_flush) + ret = bch2_journal_flush_seq(&c->journal, + ca->allocator_journal_seq_flush); + + /* + * journal error - buckets haven't actually been + * invalidated, can't discard them: + */ + if (ret) { + bch_err(ca, "journal error: %i", ret); + goto stop; + } + } + + pr_debug("free_inc now empty"); + + /* Reset front/back so we can easily sort fifo entries later: */ + ca->free_inc.front = ca->free_inc.back = 0; + ca->allocator_journal_seq_flush = 0; + ca->allocator_invalidating_data = false; + + down_read(&c->gc_lock); + while (1) { + size_t prev = fifo_used(&ca->free_inc); + + if (test_bit(BCH_FS_GC_FAILURE, &c->flags)) { + up_read(&c->gc_lock); + bch_err(ca, "gc failure"); + goto stop; + } + + /* + * Find some buckets that we can invalidate, either + * they're completely unused, or only contain clean data + * that's been written back to the backing device or + * another cache tier + */ + + pr_debug("scanning for reclaimable buckets"); + + find_reclaimable_buckets(c, ca); + + pr_debug("found %zu buckets (free_inc %zu/%zu)", + fifo_used(&ca->free_inc) - prev, + fifo_used(&ca->free_inc), ca->free_inc.size); + + trace_alloc_batch(ca, fifo_used(&ca->free_inc), + ca->free_inc.size); + + if ((ca->inc_gen_needs_gc >= ca->free_inc.size || + (!fifo_full(&ca->free_inc) && + ca->inc_gen_really_needs_gc >= + fifo_free(&ca->free_inc))) && + c->gc_thread) { + atomic_inc(&c->kick_gc); + wake_up_process(c->gc_thread); + } + + if (fifo_full(&ca->free_inc)) + break; + + if (!fifo_empty(&ca->free_inc) && + !fifo_full(&ca->free[RESERVE_MOVINGGC])) + break; + + /* + * copygc may be waiting until either its reserve fills + * up, or we can't make forward progress: + */ + ca->allocator_blocked = true; + closure_wake_up(&c->freelist_wait); + + ret = wait_buckets_available(c, ca); + if (ret) { + up_read(&c->gc_lock); + goto stop; + } + } + + ca->allocator_blocked = false; + up_read(&c->gc_lock); + + pr_debug("free_inc now %zu/%zu", + fifo_used(&ca->free_inc), + ca->free_inc.size); + + sort_free_inc(c, ca); + + /* + * free_inc is now full of newly-invalidated buckets: next, + * write out the new bucket gens: + */ + } + +stop: + pr_debug("alloc thread stopping (ret %i)", ret); + return 0; +} + +/* Allocation */ + +/* + * Open buckets represent a bucket that's currently being allocated from. They + * serve two purposes: + * + * - They track buckets that have been partially allocated, allowing for + * sub-bucket sized allocations - they're used by the sector allocator below + * + * - They provide a reference to the buckets they own that mark and sweep GC + * can find, until the new allocation has a pointer to it inserted into the + * btree + * + * When allocating some space with the sector allocator, the allocation comes + * with a reference to an open bucket - the caller is required to put that + * reference _after_ doing the index update that makes its allocation reachable. + */ + +void __bch2_open_bucket_put(struct bch_fs *c, struct open_bucket *ob) +{ + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + percpu_down_read(&c->usage_lock); + spin_lock(&ob->lock); + + bch2_mark_alloc_bucket(c, ca, PTR_BUCKET_NR(ca, &ob->ptr), + false, gc_pos_alloc(c, ob), 0); + ob->valid = false; + + spin_unlock(&ob->lock); + percpu_up_read(&c->usage_lock); + + spin_lock(&c->freelist_lock); + ob->freelist = c->open_buckets_freelist; + c->open_buckets_freelist = ob - c->open_buckets; + c->open_buckets_nr_free++; + spin_unlock(&c->freelist_lock); + + closure_wake_up(&c->open_buckets_wait); +} + +static struct open_bucket *bch2_open_bucket_alloc(struct bch_fs *c) +{ + struct open_bucket *ob; + + BUG_ON(!c->open_buckets_freelist || !c->open_buckets_nr_free); + + ob = c->open_buckets + c->open_buckets_freelist; + c->open_buckets_freelist = ob->freelist; + atomic_set(&ob->pin, 1); + + c->open_buckets_nr_free--; + return ob; +} + +/* _only_ for allocating the journal on a new device: */ +long bch2_bucket_alloc_new_fs(struct bch_dev *ca) +{ + struct bucket_array *buckets; + ssize_t b; + + rcu_read_lock(); + buckets = bucket_array(ca); + + for (b = ca->mi.first_bucket; b < ca->mi.nbuckets; b++) + if (is_available_bucket(buckets->b[b].mark)) + goto success; + b = -1; +success: + rcu_read_unlock(); + return b; +} + +static inline unsigned open_buckets_reserved(enum alloc_reserve reserve) +{ + switch (reserve) { + case RESERVE_ALLOC: + return 0; + case RESERVE_BTREE: + return BTREE_NODE_RESERVE / 2; + default: + return BTREE_NODE_RESERVE; + } +} + +/** + * bch_bucket_alloc - allocate a single bucket from a specific device + * + * Returns index of bucket on success, 0 on failure + * */ +int bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca, + enum alloc_reserve reserve, + bool may_alloc_partial, + struct closure *cl) +{ + struct bucket_array *buckets; + struct open_bucket *ob; + long bucket; + + spin_lock(&c->freelist_lock); + + if (may_alloc_partial && + ca->open_buckets_partial_nr) { + int ret = ca->open_buckets_partial[--ca->open_buckets_partial_nr]; + c->open_buckets[ret].on_partial_list = false; + spin_unlock(&c->freelist_lock); + return ret; + } + + if (unlikely(c->open_buckets_nr_free <= open_buckets_reserved(reserve))) { + if (cl) + closure_wait(&c->open_buckets_wait, cl); + spin_unlock(&c->freelist_lock); + trace_open_bucket_alloc_fail(ca, reserve); + return OPEN_BUCKETS_EMPTY; + } + + if (likely(fifo_pop(&ca->free[RESERVE_NONE], bucket))) + goto out; + + switch (reserve) { + case RESERVE_ALLOC: + if (fifo_pop(&ca->free[RESERVE_BTREE], bucket)) + goto out; + break; + case RESERVE_BTREE: + if (fifo_used(&ca->free[RESERVE_BTREE]) * 2 >= + ca->free[RESERVE_BTREE].size && + fifo_pop(&ca->free[RESERVE_BTREE], bucket)) + goto out; + break; + case RESERVE_MOVINGGC: + if (fifo_pop(&ca->free[RESERVE_MOVINGGC], bucket)) + goto out; + break; + default: + break; + } + + if (cl) + closure_wait(&c->freelist_wait, cl); + + spin_unlock(&c->freelist_lock); + + trace_bucket_alloc_fail(ca, reserve); + return FREELIST_EMPTY; +out: + verify_not_on_freelist(c, ca, bucket); + + ob = bch2_open_bucket_alloc(c); + + spin_lock(&ob->lock); + buckets = bucket_array(ca); + + ob->valid = true; + ob->sectors_free = ca->mi.bucket_size; + ob->ptr = (struct bch_extent_ptr) { + .gen = buckets->b[bucket].mark.gen, + .offset = bucket_to_sector(ca, bucket), + .dev = ca->dev_idx, + }; + + bucket_io_clock_reset(c, ca, bucket, READ); + bucket_io_clock_reset(c, ca, bucket, WRITE); + spin_unlock(&ob->lock); + + spin_unlock(&c->freelist_lock); + + bch2_wake_allocator(ca); + + trace_bucket_alloc(ca, reserve); + return ob - c->open_buckets; +} + +static int __dev_alloc_cmp(struct write_point *wp, + unsigned l, unsigned r) +{ + return ((wp->next_alloc[l] > wp->next_alloc[r]) - + (wp->next_alloc[l] < wp->next_alloc[r])); +} + +#define dev_alloc_cmp(l, r) __dev_alloc_cmp(wp, l, r) + +struct dev_alloc_list bch2_wp_alloc_list(struct bch_fs *c, + struct write_point *wp, + struct bch_devs_mask *devs) +{ + struct dev_alloc_list ret = { .nr = 0 }; + struct bch_dev *ca; + unsigned i; + + for_each_member_device_rcu(ca, c, i, devs) + ret.devs[ret.nr++] = i; + + bubble_sort(ret.devs, ret.nr, dev_alloc_cmp); + return ret; +} + +void bch2_wp_rescale(struct bch_fs *c, struct bch_dev *ca, + struct write_point *wp) +{ + u64 *v = wp->next_alloc + ca->dev_idx; + u64 free_space = dev_buckets_free(c, ca); + u64 free_space_inv = free_space + ? div64_u64(1ULL << 48, free_space) + : 1ULL << 48; + u64 scale = *v / 4; + + if (*v + free_space_inv >= *v) + *v += free_space_inv; + else + *v = U64_MAX; + + for (v = wp->next_alloc; + v < wp->next_alloc + ARRAY_SIZE(wp->next_alloc); v++) + *v = *v < scale ? 0 : *v - scale; +} + +static enum bucket_alloc_ret bch2_bucket_alloc_set(struct bch_fs *c, + struct write_point *wp, + unsigned nr_replicas, + enum alloc_reserve reserve, + struct bch_devs_mask *devs, + struct closure *cl) +{ + enum bucket_alloc_ret ret = NO_DEVICES; + struct dev_alloc_list devs_sorted; + struct bch_dev *ca; + unsigned i, nr_ptrs_effective = 0; + bool have_cache_dev = false; + + BUG_ON(nr_replicas > ARRAY_SIZE(wp->ptrs)); + + for (i = wp->first_ptr; i < wp->nr_ptrs; i++) { + ca = bch_dev_bkey_exists(c, wp->ptrs[i]->ptr.dev); + + nr_ptrs_effective += ca->mi.durability; + have_cache_dev |= !ca->mi.durability; + } + + if (nr_ptrs_effective >= nr_replicas) + return ALLOC_SUCCESS; + + devs_sorted = bch2_wp_alloc_list(c, wp, devs); + + for (i = 0; i < devs_sorted.nr; i++) { + int ob; + + ca = rcu_dereference(c->devs[devs_sorted.devs[i]]); + if (!ca) + continue; + + if (!ca->mi.durability && + (have_cache_dev || + wp->type != BCH_DATA_USER)) + continue; + + ob = bch2_bucket_alloc(c, ca, reserve, + wp->type == BCH_DATA_USER, cl); + if (ob < 0) { + ret = ob; + if (ret == OPEN_BUCKETS_EMPTY) + break; + continue; + } + + BUG_ON(ob <= 0 || ob > U8_MAX); + BUG_ON(wp->nr_ptrs >= ARRAY_SIZE(wp->ptrs)); + + wp->ptrs[wp->nr_ptrs++] = c->open_buckets + ob; + + bch2_wp_rescale(c, ca, wp); + + nr_ptrs_effective += ca->mi.durability; + have_cache_dev |= !ca->mi.durability; + + __clear_bit(ca->dev_idx, devs->d); + + if (nr_ptrs_effective >= nr_replicas) { + ret = ALLOC_SUCCESS; + break; + } + } + + EBUG_ON(reserve == RESERVE_MOVINGGC && + ret != ALLOC_SUCCESS && + ret != OPEN_BUCKETS_EMPTY); + + switch (ret) { + case ALLOC_SUCCESS: + return 0; + case NO_DEVICES: + return -EROFS; + case FREELIST_EMPTY: + case OPEN_BUCKETS_EMPTY: + return cl ? -EAGAIN : -ENOSPC; + default: + BUG(); + } +} + +/* Sector allocator */ + +static void writepoint_drop_ptr(struct bch_fs *c, + struct write_point *wp, + unsigned i) +{ + struct open_bucket *ob = wp->ptrs[i]; + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + BUG_ON(ca->open_buckets_partial_nr >= + ARRAY_SIZE(ca->open_buckets_partial)); + + if (wp->type == BCH_DATA_USER) { + spin_lock(&c->freelist_lock); + ob->on_partial_list = true; + ca->open_buckets_partial[ca->open_buckets_partial_nr++] = + ob - c->open_buckets; + spin_unlock(&c->freelist_lock); + + closure_wake_up(&c->open_buckets_wait); + closure_wake_up(&c->freelist_wait); + } else { + bch2_open_bucket_put(c, ob); + } + + array_remove_item(wp->ptrs, wp->nr_ptrs, i); + + if (i < wp->first_ptr) + wp->first_ptr--; +} + +static void writepoint_drop_ptrs(struct bch_fs *c, + struct write_point *wp, + u16 target, bool in_target) +{ + int i; + + for (i = wp->first_ptr - 1; i >= 0; --i) + if (bch2_dev_in_target(c, wp->ptrs[i]->ptr.dev, + target) == in_target) + writepoint_drop_ptr(c, wp, i); +} + +static void verify_not_stale(struct bch_fs *c, const struct write_point *wp) +{ +#ifdef CONFIG_BCACHEFS_DEBUG + struct open_bucket *ob; + unsigned i; + + writepoint_for_each_ptr_all(wp, ob, i) { + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + BUG_ON(ptr_stale(ca, &ob->ptr)); + } +#endif +} + +static int open_bucket_add_buckets(struct bch_fs *c, + u16 target, + struct write_point *wp, + struct bch_devs_list *devs_have, + unsigned nr_replicas, + enum alloc_reserve reserve, + struct closure *cl) +{ + struct bch_devs_mask devs = c->rw_devs[wp->type]; + const struct bch_devs_mask *t; + struct open_bucket *ob; + unsigned i; + int ret; + + percpu_down_read(&c->usage_lock); + rcu_read_lock(); + + /* Don't allocate from devices we already have pointers to: */ + for (i = 0; i < devs_have->nr; i++) + __clear_bit(devs_have->devs[i], devs.d); + + writepoint_for_each_ptr_all(wp, ob, i) + __clear_bit(ob->ptr.dev, devs.d); + + t = bch2_target_to_mask(c, target); + if (t) + bitmap_and(devs.d, devs.d, t->d, BCH_SB_MEMBERS_MAX); + + ret = bch2_bucket_alloc_set(c, wp, nr_replicas, reserve, &devs, cl); + + rcu_read_unlock(); + percpu_up_read(&c->usage_lock); + + return ret; +} + +static struct write_point *__writepoint_find(struct hlist_head *head, + unsigned long write_point) +{ + struct write_point *wp; + + hlist_for_each_entry_rcu(wp, head, node) + if (wp->write_point == write_point) + return wp; + + return NULL; +} + +static struct hlist_head *writepoint_hash(struct bch_fs *c, + unsigned long write_point) +{ + unsigned hash = + hash_long(write_point, ilog2(ARRAY_SIZE(c->write_points_hash))); + + return &c->write_points_hash[hash]; +} + +static struct write_point *writepoint_find(struct bch_fs *c, + unsigned long write_point) +{ + struct write_point *wp, *oldest; + struct hlist_head *head; + + if (!(write_point & 1UL)) { + wp = (struct write_point *) write_point; + mutex_lock(&wp->lock); + return wp; + } + + head = writepoint_hash(c, write_point); +restart_find: + wp = __writepoint_find(head, write_point); + if (wp) { +lock_wp: + mutex_lock(&wp->lock); + if (wp->write_point == write_point) + goto out; + mutex_unlock(&wp->lock); + goto restart_find; + } + + oldest = NULL; + for (wp = c->write_points; + wp < c->write_points + ARRAY_SIZE(c->write_points); + wp++) + if (!oldest || time_before64(wp->last_used, oldest->last_used)) + oldest = wp; + + mutex_lock(&oldest->lock); + mutex_lock(&c->write_points_hash_lock); + wp = __writepoint_find(head, write_point); + if (wp && wp != oldest) { + mutex_unlock(&c->write_points_hash_lock); + mutex_unlock(&oldest->lock); + goto lock_wp; + } + + wp = oldest; + hlist_del_rcu(&wp->node); + wp->write_point = write_point; + hlist_add_head_rcu(&wp->node, head); + mutex_unlock(&c->write_points_hash_lock); +out: + wp->last_used = sched_clock(); + return wp; +} + +/* + * Get us an open_bucket we can allocate from, return with it locked: + */ +struct write_point *bch2_alloc_sectors_start(struct bch_fs *c, + unsigned target, + struct write_point_specifier write_point, + struct bch_devs_list *devs_have, + unsigned nr_replicas, + unsigned nr_replicas_required, + enum alloc_reserve reserve, + unsigned flags, + struct closure *cl) +{ + struct write_point *wp; + struct open_bucket *ob; + struct bch_dev *ca; + unsigned nr_ptrs_have, nr_ptrs_effective; + int ret, i, cache_idx = -1; + + BUG_ON(!nr_replicas || !nr_replicas_required); + + wp = writepoint_find(c, write_point.v); + + wp->first_ptr = 0; + + /* does writepoint have ptrs we can't use? */ + writepoint_for_each_ptr(wp, ob, i) + if (bch2_dev_list_has_dev(*devs_have, ob->ptr.dev)) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + } + + nr_ptrs_have = wp->first_ptr; + + /* does writepoint have ptrs we don't want to use? */ + if (target) + writepoint_for_each_ptr(wp, ob, i) + if (!bch2_dev_in_target(c, ob->ptr.dev, target)) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + } + + if (flags & BCH_WRITE_ONLY_SPECIFIED_DEVS) { + ret = open_bucket_add_buckets(c, target, wp, devs_have, + nr_replicas, reserve, cl); + } else { + ret = open_bucket_add_buckets(c, target, wp, devs_have, + nr_replicas, reserve, NULL); + if (!ret) + goto alloc_done; + + wp->first_ptr = nr_ptrs_have; + + ret = open_bucket_add_buckets(c, 0, wp, devs_have, + nr_replicas, reserve, cl); + } + + if (ret && ret != -EROFS) + goto err; +alloc_done: + /* check for more than one cache: */ + for (i = wp->nr_ptrs - 1; i >= wp->first_ptr; --i) { + ca = bch_dev_bkey_exists(c, wp->ptrs[i]->ptr.dev); + + if (ca->mi.durability) + continue; + + /* + * if we ended up with more than one cache device, prefer the + * one in the target we want: + */ + if (cache_idx >= 0) { + if (!bch2_dev_in_target(c, wp->ptrs[i]->ptr.dev, + target)) { + writepoint_drop_ptr(c, wp, i); + } else { + writepoint_drop_ptr(c, wp, cache_idx); + cache_idx = i; + } + } else { + cache_idx = i; + } + } + + /* we might have more effective replicas than required: */ + nr_ptrs_effective = 0; + writepoint_for_each_ptr(wp, ob, i) { + ca = bch_dev_bkey_exists(c, ob->ptr.dev); + nr_ptrs_effective += ca->mi.durability; + } + + if (ret == -EROFS && + nr_ptrs_effective >= nr_replicas_required) + ret = 0; + + if (ret) + goto err; + + if (nr_ptrs_effective > nr_replicas) { + writepoint_for_each_ptr(wp, ob, i) { + ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + if (ca->mi.durability && + ca->mi.durability <= nr_ptrs_effective - nr_replicas && + !bch2_dev_in_target(c, ob->ptr.dev, target)) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + nr_ptrs_effective -= ca->mi.durability; + } + } + } + + if (nr_ptrs_effective > nr_replicas) { + writepoint_for_each_ptr(wp, ob, i) { + ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + if (ca->mi.durability && + ca->mi.durability <= nr_ptrs_effective - nr_replicas) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + nr_ptrs_effective -= ca->mi.durability; + } + } + } + + /* Remove pointers we don't want to use: */ + if (target) + writepoint_drop_ptrs(c, wp, target, false); + + BUG_ON(wp->first_ptr >= wp->nr_ptrs); + BUG_ON(nr_ptrs_effective < nr_replicas_required); + + wp->sectors_free = UINT_MAX; + + writepoint_for_each_ptr(wp, ob, i) + wp->sectors_free = min(wp->sectors_free, ob->sectors_free); + + BUG_ON(!wp->sectors_free || wp->sectors_free == UINT_MAX); + + verify_not_stale(c, wp); + + return wp; +err: + mutex_unlock(&wp->lock); + return ERR_PTR(ret); +} + +/* + * Append pointers to the space we just allocated to @k, and mark @sectors space + * as allocated out of @ob + */ +void bch2_alloc_sectors_append_ptrs(struct bch_fs *c, struct write_point *wp, + struct bkey_i_extent *e, unsigned sectors) +{ + struct open_bucket *ob; + unsigned i; + + BUG_ON(sectors > wp->sectors_free); + wp->sectors_free -= sectors; + + writepoint_for_each_ptr(wp, ob, i) { + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + struct bch_extent_ptr tmp = ob->ptr; + + EBUG_ON(bch2_extent_has_device(extent_i_to_s_c(e), ob->ptr.dev)); + + tmp.cached = bkey_extent_is_cached(&e->k) || + (!ca->mi.durability && wp->type == BCH_DATA_USER); + + tmp.offset += ca->mi.bucket_size - ob->sectors_free; + extent_ptr_append(e, tmp); + + BUG_ON(sectors > ob->sectors_free); + ob->sectors_free -= sectors; + } +} + +/* + * Append pointers to the space we just allocated to @k, and mark @sectors space + * as allocated out of @ob + */ +void bch2_alloc_sectors_done(struct bch_fs *c, struct write_point *wp) +{ + int i; + + for (i = wp->nr_ptrs - 1; i >= 0; --i) { + struct open_bucket *ob = wp->ptrs[i]; + + if (!ob->sectors_free) { + array_remove_item(wp->ptrs, wp->nr_ptrs, i); + bch2_open_bucket_put(c, ob); + } + } + + mutex_unlock(&wp->lock); +} + +/* Startup/shutdown (ro/rw): */ + +void bch2_recalc_capacity(struct bch_fs *c) +{ + struct bch_dev *ca; + u64 total_capacity, capacity = 0, reserved_sectors = 0; + unsigned long ra_pages = 0; + unsigned i, j; + + lockdep_assert_held(&c->state_lock); + + for_each_online_member(ca, c, i) { + struct backing_dev_info *bdi = ca->disk_sb.bdev->bd_disk->bdi; + + ra_pages += bdi->ra_pages; + } + + bch2_set_ra_pages(c, ra_pages); + + for_each_rw_member(ca, c, i) { + size_t reserve = 0; + + /* + * We need to reserve buckets (from the number + * of currently available buckets) against + * foreground writes so that mainly copygc can + * make forward progress. + * + * We need enough to refill the various reserves + * from scratch - copygc will use its entire + * reserve all at once, then run against when + * its reserve is refilled (from the formerly + * available buckets). + * + * This reserve is just used when considering if + * allocations for foreground writes must wait - + * not -ENOSPC calculations. + */ + for (j = 0; j < RESERVE_NONE; j++) + reserve += ca->free[j].size; + + reserve += ca->free_inc.size; + + reserve += ARRAY_SIZE(c->write_points); + + reserve += 1; /* btree write point */ + + reserved_sectors += bucket_to_sector(ca, reserve); + + capacity += bucket_to_sector(ca, ca->mi.nbuckets - + ca->mi.first_bucket); + } + + total_capacity = capacity; + + capacity *= (100 - c->opts.gc_reserve_percent); + capacity = div64_u64(capacity, 100); + + BUG_ON(reserved_sectors > total_capacity); + + capacity = min(capacity, total_capacity - reserved_sectors); + + c->capacity = capacity; + + if (c->capacity) { + bch2_io_timer_add(&c->io_clock[READ], + &c->bucket_clock[READ].rescale); + bch2_io_timer_add(&c->io_clock[WRITE], + &c->bucket_clock[WRITE].rescale); + } else { + bch2_io_timer_del(&c->io_clock[READ], + &c->bucket_clock[READ].rescale); + bch2_io_timer_del(&c->io_clock[WRITE], + &c->bucket_clock[WRITE].rescale); + } + + /* Wake up case someone was waiting for buckets */ + closure_wake_up(&c->freelist_wait); +} + +static void bch2_stop_write_point(struct bch_fs *c, struct bch_dev *ca, + struct write_point *wp) +{ + struct bch_devs_mask not_self; + + bitmap_complement(not_self.d, ca->self.d, BCH_SB_MEMBERS_MAX); + + mutex_lock(&wp->lock); + wp->first_ptr = wp->nr_ptrs; + writepoint_drop_ptrs(c, wp, dev_to_target(ca->dev_idx), true); + mutex_unlock(&wp->lock); +} + +static bool bch2_dev_has_open_write_point(struct bch_fs *c, struct bch_dev *ca) +{ + struct open_bucket *ob; + bool ret = false; + + for (ob = c->open_buckets; + ob < c->open_buckets + ARRAY_SIZE(c->open_buckets); + ob++) { + spin_lock(&ob->lock); + if (ob->valid && !ob->on_partial_list && + ob->ptr.dev == ca->dev_idx) + ret = true; + spin_unlock(&ob->lock); + } + + return ret; +} + +/* device goes ro: */ +void bch2_dev_allocator_remove(struct bch_fs *c, struct bch_dev *ca) +{ + unsigned i; + + BUG_ON(ca->alloc_thread); + + /* First, remove device from allocation groups: */ + + for (i = 0; i < ARRAY_SIZE(c->rw_devs); i++) + clear_bit(ca->dev_idx, c->rw_devs[i].d); + + /* + * Capacity is calculated based off of devices in allocation groups: + */ + bch2_recalc_capacity(c); + + /* Next, close write points that point to this device... */ + for (i = 0; i < ARRAY_SIZE(c->write_points); i++) + bch2_stop_write_point(c, ca, &c->write_points[i]); + + bch2_stop_write_point(c, ca, &ca->copygc_write_point); + bch2_stop_write_point(c, ca, &c->rebalance_write_point); + bch2_stop_write_point(c, ca, &c->btree_write_point); + + mutex_lock(&c->btree_reserve_cache_lock); + while (c->btree_reserve_cache_nr) { + struct btree_alloc *a = + &c->btree_reserve_cache[--c->btree_reserve_cache_nr]; + + bch2_open_bucket_put_refs(c, &a->ob.nr, a->ob.refs); + } + mutex_unlock(&c->btree_reserve_cache_lock); + + /* + * Wake up threads that were blocked on allocation, so they can notice + * the device can no longer be removed and the capacity has changed: + */ + closure_wake_up(&c->freelist_wait); + + /* + * journal_res_get() can block waiting for free space in the journal - + * it needs to notice there may not be devices to allocate from anymore: + */ + wake_up(&c->journal.wait); + + /* Now wait for any in flight writes: */ + + closure_wait_event(&c->open_buckets_wait, + !bch2_dev_has_open_write_point(c, ca)); +} + +/* device goes rw: */ +void bch2_dev_allocator_add(struct bch_fs *c, struct bch_dev *ca) +{ + unsigned i; + + for (i = 0; i < ARRAY_SIZE(c->rw_devs); i++) + if (ca->mi.data_allowed & (1 << i)) + set_bit(ca->dev_idx, c->rw_devs[i].d); +} + +/* stop allocator thread: */ +void bch2_dev_allocator_stop(struct bch_dev *ca) +{ + struct task_struct *p; + + p = rcu_dereference_protected(ca->alloc_thread, 1); + ca->alloc_thread = NULL; + + /* + * We need an rcu barrier between setting ca->alloc_thread = NULL and + * the thread shutting down to avoid bch2_wake_allocator() racing: + * + * XXX: it would be better to have the rcu barrier be asynchronous + * instead of blocking us here + */ + synchronize_rcu(); + + if (p) { + kthread_stop(p); + put_task_struct(p); + } +} + +/* start allocator thread: */ +int bch2_dev_allocator_start(struct bch_dev *ca) +{ + struct task_struct *p; + + /* + * allocator thread already started? + */ + if (ca->alloc_thread) + return 0; + + p = kthread_create(bch2_allocator_thread, ca, + "bch_alloc[%s]", ca->name); + if (IS_ERR(p)) + return PTR_ERR(p); + + get_task_struct(p); + rcu_assign_pointer(ca->alloc_thread, p); + wake_up_process(p); + return 0; +} + +static void allocator_start_issue_discards(struct bch_fs *c) +{ + struct bch_dev *ca; + unsigned dev_iter; + size_t i, bu; + + for_each_rw_member(ca, c, dev_iter) { + unsigned done = 0; + + fifo_for_each_entry(bu, &ca->free_inc, i) { + if (done == ca->nr_invalidated) + break; + + blkdev_issue_discard(ca->disk_sb.bdev, + bucket_to_sector(ca, bu), + ca->mi.bucket_size, GFP_NOIO); + done++; + } + } +} + +static int __bch2_fs_allocator_start(struct bch_fs *c) +{ + struct bch_dev *ca; + size_t bu, i; + unsigned dev_iter; + u64 journal_seq = 0; + bool invalidating_data = false; + int ret = 0; + + if (test_bit(BCH_FS_GC_FAILURE, &c->flags)) + return -1; + + /* Scan for buckets that are already invalidated: */ + for_each_rw_member(ca, c, dev_iter) { + struct btree_iter iter; + struct bucket_mark m; + struct bkey_s_c k; + + for_each_btree_key(&iter, c, BTREE_ID_ALLOC, POS(ca->dev_idx, 0), 0, k) { + if (k.k->type != BCH_ALLOC) + continue; + + bu = k.k->p.offset; + m = READ_ONCE(bucket(ca, bu)->mark); + + if (!is_available_bucket(m) || m.cached_sectors) + continue; + + percpu_down_read(&c->usage_lock); + bch2_mark_alloc_bucket(c, ca, bu, true, + gc_pos_alloc(c, NULL), + BCH_BUCKET_MARK_MAY_MAKE_UNAVAILABLE| + BCH_BUCKET_MARK_GC_LOCK_HELD); + percpu_up_read(&c->usage_lock); + + fifo_push(&ca->free_inc, bu); + ca->nr_invalidated++; + + if (fifo_full(&ca->free_inc)) + break; + } + bch2_btree_iter_unlock(&iter); + } + + /* did we find enough buckets? */ + for_each_rw_member(ca, c, dev_iter) + if (fifo_used(&ca->free_inc) < ca->free[RESERVE_BTREE].size) { + percpu_ref_put(&ca->io_ref); + goto not_enough; + } + + return 0; +not_enough: + pr_debug("did not find enough empty buckets; issuing discards"); + + /* clear out free_inc - find_reclaimable_buckets() assumes it's empty */ + for_each_rw_member(ca, c, dev_iter) + discard_invalidated_buckets(c, ca); + + pr_debug("scanning for reclaimable buckets"); + + for_each_rw_member(ca, c, dev_iter) { + BUG_ON(!fifo_empty(&ca->free_inc)); + ca->free_inc.front = ca->free_inc.back = 0; + + find_reclaimable_buckets(c, ca); + sort_free_inc(c, ca); + + invalidating_data |= ca->allocator_invalidating_data; + + fifo_for_each_entry(bu, &ca->free_inc, i) + if (!fifo_push(&ca->free[RESERVE_BTREE], bu)) + break; + } + + pr_debug("done scanning for reclaimable buckets"); + + /* + * We're moving buckets to freelists _before_ they've been marked as + * invalidated on disk - we have to so that we can allocate new btree + * nodes to mark them as invalidated on disk. + * + * However, we can't _write_ to any of these buckets yet - they might + * have cached data in them, which is live until they're marked as + * invalidated on disk: + */ + if (invalidating_data) { + pr_debug("invalidating existing data"); + set_bit(BCH_FS_HOLD_BTREE_WRITES, &c->flags); + } else { + pr_debug("issuing discards"); + allocator_start_issue_discards(c); + } + + /* + * XXX: it's possible for this to deadlock waiting on journal reclaim, + * since we're holding btree writes. What then? + */ + + for_each_rw_member(ca, c, dev_iter) { + ret = bch2_invalidate_free_inc(c, ca, &journal_seq, + ca->free[RESERVE_BTREE].size, + false); + if (ret) { + percpu_ref_put(&ca->io_ref); + return ret; + } + } + + if (invalidating_data) { + pr_debug("flushing journal"); + + ret = bch2_journal_flush_seq(&c->journal, journal_seq); + if (ret) + return ret; + + pr_debug("issuing discards"); + allocator_start_issue_discards(c); + } + + for_each_rw_member(ca, c, dev_iter) + while (ca->nr_invalidated) { + BUG_ON(!fifo_pop(&ca->free_inc, bu)); + ca->nr_invalidated--; + } + + set_bit(BCH_FS_ALLOCATOR_STARTED, &c->flags); + + /* now flush dirty btree nodes: */ + if (invalidating_data) { + struct bucket_table *tbl; + struct rhash_head *pos; + struct btree *b; + bool flush_updates; + size_t nr_pending_updates; + + clear_bit(BCH_FS_HOLD_BTREE_WRITES, &c->flags); +again: + pr_debug("flushing dirty btree nodes"); + cond_resched(); + + flush_updates = false; + nr_pending_updates = bch2_btree_interior_updates_nr_pending(c); + + + rcu_read_lock(); + for_each_cached_btree(b, c, tbl, i, pos) + if (btree_node_dirty(b) && (!b->written || b->level)) { + if (btree_node_may_write(b)) { + rcu_read_unlock(); + btree_node_lock_type(c, b, SIX_LOCK_read); + bch2_btree_node_write(c, b, SIX_LOCK_read); + six_unlock_read(&b->lock); + goto again; + } else { + flush_updates = true; + } + } + rcu_read_unlock(); + + /* + * This is ugly, but it's needed to flush btree node writes + * without spinning... + */ + if (flush_updates) { + closure_wait_event(&c->btree_interior_update_wait, + bch2_btree_interior_updates_nr_pending(c) < + nr_pending_updates); + goto again; + } + } + + return 0; +} + +int bch2_fs_allocator_start(struct bch_fs *c) +{ + struct bch_dev *ca; + unsigned i; + int ret; + + down_read(&c->gc_lock); + ret = __bch2_fs_allocator_start(c); + up_read(&c->gc_lock); + + if (ret) + return ret; + + for_each_rw_member(ca, c, i) { + ret = bch2_dev_allocator_start(ca); + if (ret) { + percpu_ref_put(&ca->io_ref); + return ret; + } + } + + return bch2_alloc_write(c); +} + +void bch2_fs_allocator_init(struct bch_fs *c) +{ + struct open_bucket *ob; + struct write_point *wp; + + mutex_init(&c->write_points_hash_lock); + spin_lock_init(&c->freelist_lock); + bch2_bucket_clock_init(c, READ); + bch2_bucket_clock_init(c, WRITE); + + /* open bucket 0 is a sentinal NULL: */ + spin_lock_init(&c->open_buckets[0].lock); + + for (ob = c->open_buckets + 1; + ob < c->open_buckets + ARRAY_SIZE(c->open_buckets); ob++) { + spin_lock_init(&ob->lock); + c->open_buckets_nr_free++; + + ob->freelist = c->open_buckets_freelist; + c->open_buckets_freelist = ob - c->open_buckets; + } + + writepoint_init(&c->btree_write_point, BCH_DATA_BTREE); + writepoint_init(&c->rebalance_write_point, BCH_DATA_USER); + + for (wp = c->write_points; + wp < c->write_points + ARRAY_SIZE(c->write_points); wp++) { + writepoint_init(wp, BCH_DATA_USER); + + wp->last_used = sched_clock(); + wp->write_point = (unsigned long) wp; + hlist_add_head_rcu(&wp->node, writepoint_hash(c, wp->write_point)); + } + + c->pd_controllers_update_seconds = 5; + INIT_DELAYED_WORK(&c->pd_controllers_update, pd_controllers_update); +} |