diff options
Diffstat (limited to 'fs/bcachefs/btree_cache.c')
| -rw-r--r-- | fs/bcachefs/btree_cache.c | 1491 |
1 files changed, 1491 insertions, 0 deletions
diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c new file mode 100644 index 000000000000..7123019ab3bc --- /dev/null +++ b/fs/bcachefs/btree_cache.c @@ -0,0 +1,1491 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "bcachefs.h" +#include "bbpos.h" +#include "bkey_buf.h" +#include "btree_cache.h" +#include "btree_io.h" +#include "btree_iter.h" +#include "btree_locking.h" +#include "debug.h" +#include "errcode.h" +#include "error.h" +#include "journal.h" +#include "trace.h" + +#include <linux/prefetch.h> +#include <linux/sched/mm.h> +#include <linux/swap.h> + +#define BTREE_CACHE_NOT_FREED_INCREMENT(counter) \ +do { \ + if (shrinker_counter) \ + bc->not_freed[BCH_BTREE_CACHE_NOT_FREED_##counter]++; \ +} while (0) + +const char * const bch2_btree_node_flags[] = { +#define x(f) #f, + BTREE_FLAGS() +#undef x + NULL +}; + +void bch2_recalc_btree_reserve(struct bch_fs *c) +{ + unsigned reserve = 16; + + if (!c->btree_roots_known[0].b) + reserve += 8; + + for (unsigned i = 0; i < btree_id_nr_alive(c); i++) { + struct btree_root *r = bch2_btree_id_root(c, i); + + if (r->b) + reserve += min_t(unsigned, 1, r->b->c.level) * 8; + } + + c->btree_cache.nr_reserve = reserve; +} + +static inline size_t btree_cache_can_free(struct btree_cache_list *list) +{ + struct btree_cache *bc = container_of(list, struct btree_cache, live[list->idx]); + + size_t can_free = list->nr; + if (!list->idx) + can_free = max_t(ssize_t, 0, can_free - bc->nr_reserve); + return can_free; +} + +static void btree_node_to_freedlist(struct btree_cache *bc, struct btree *b) +{ + BUG_ON(!list_empty(&b->list)); + + if (b->c.lock.readers) + list_add(&b->list, &bc->freed_pcpu); + else + list_add(&b->list, &bc->freed_nonpcpu); +} + +static void __bch2_btree_node_to_freelist(struct btree_cache *bc, struct btree *b) +{ + BUG_ON(!list_empty(&b->list)); + BUG_ON(!b->data); + + bc->nr_freeable++; + list_add(&b->list, &bc->freeable); +} + +void bch2_btree_node_to_freelist(struct bch_fs *c, struct btree *b) +{ + struct btree_cache *bc = &c->btree_cache; + + mutex_lock(&bc->lock); + __bch2_btree_node_to_freelist(bc, b); + mutex_unlock(&bc->lock); + + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); +} + +static void __btree_node_data_free(struct btree_cache *bc, struct btree *b) +{ + BUG_ON(!list_empty(&b->list)); + BUG_ON(btree_node_hashed(b)); + + /* + * This should really be done in slub/vmalloc, but we're using the + * kmalloc_large() path, so we're working around a slub bug by doing + * this here: + */ + if (b->data) + mm_account_reclaimed_pages(btree_buf_bytes(b) / PAGE_SIZE); + if (b->aux_data) + mm_account_reclaimed_pages(btree_aux_data_bytes(b) / PAGE_SIZE); + + EBUG_ON(btree_node_write_in_flight(b)); + + clear_btree_node_just_written(b); + + kvfree(b->data); + b->data = NULL; +#ifdef __KERNEL__ + kvfree(b->aux_data); +#else + munmap(b->aux_data, btree_aux_data_bytes(b)); +#endif + b->aux_data = NULL; + + btree_node_to_freedlist(bc, b); +} + +static void btree_node_data_free(struct btree_cache *bc, struct btree *b) +{ + BUG_ON(list_empty(&b->list)); + list_del_init(&b->list); + --bc->nr_freeable; + __btree_node_data_free(bc, b); +} + +static int bch2_btree_cache_cmp_fn(struct rhashtable_compare_arg *arg, + const void *obj) +{ + const struct btree *b = obj; + const u64 *v = arg->key; + + return b->hash_val == *v ? 0 : 1; +} + +static const struct rhashtable_params bch_btree_cache_params = { + .head_offset = offsetof(struct btree, hash), + .key_offset = offsetof(struct btree, hash_val), + .key_len = sizeof(u64), + .obj_cmpfn = bch2_btree_cache_cmp_fn, + .automatic_shrinking = true, +}; + +static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp) +{ + BUG_ON(b->data || b->aux_data); + + gfp |= __GFP_ACCOUNT|__GFP_RECLAIMABLE; + + b->data = kvmalloc(btree_buf_bytes(b), gfp); + if (!b->data) + return -BCH_ERR_ENOMEM_btree_node_mem_alloc; +#ifdef __KERNEL__ + b->aux_data = kvmalloc(btree_aux_data_bytes(b), gfp); +#else + b->aux_data = mmap(NULL, btree_aux_data_bytes(b), + PROT_READ|PROT_WRITE|PROT_EXEC, + MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); + if (b->aux_data == MAP_FAILED) + b->aux_data = NULL; +#endif + if (!b->aux_data) { + kvfree(b->data); + b->data = NULL; + return -BCH_ERR_ENOMEM_btree_node_mem_alloc; + } + + return 0; +} + +static struct btree *__btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp) +{ + struct btree *b; + + b = kzalloc(sizeof(struct btree), gfp); + if (!b) + return NULL; + + bkey_btree_ptr_init(&b->key); + INIT_LIST_HEAD(&b->list); + INIT_LIST_HEAD(&b->write_blocked); + b->byte_order = ilog2(c->opts.btree_node_size); + return b; +} + +struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c) +{ + struct btree_cache *bc = &c->btree_cache; + struct btree *b; + + b = __btree_node_mem_alloc(c, GFP_KERNEL); + if (!b) + return NULL; + + if (btree_node_data_alloc(c, b, GFP_KERNEL)) { + kfree(b); + return NULL; + } + + bch2_btree_lock_init(&b->c, 0); + + __bch2_btree_node_to_freelist(bc, b); + return b; +} + +static inline bool __btree_node_pinned(struct btree_cache *bc, struct btree *b) +{ + struct bbpos pos = BBPOS(b->c.btree_id, b->key.k.p); + + u64 mask = bc->pinned_nodes_mask[!!b->c.level]; + + return ((mask & BIT_ULL(b->c.btree_id)) && + bbpos_cmp(bc->pinned_nodes_start, pos) < 0 && + bbpos_cmp(bc->pinned_nodes_end, pos) >= 0); +} + +void bch2_node_pin(struct bch_fs *c, struct btree *b) +{ + struct btree_cache *bc = &c->btree_cache; + + mutex_lock(&bc->lock); + BUG_ON(!__btree_node_pinned(bc, b)); + if (b != btree_node_root(c, b) && !btree_node_pinned(b)) { + set_btree_node_pinned(b); + list_move(&b->list, &bc->live[1].list); + bc->live[0].nr--; + bc->live[1].nr++; + } + mutex_unlock(&bc->lock); +} + +void bch2_btree_cache_unpin(struct bch_fs *c) +{ + struct btree_cache *bc = &c->btree_cache; + struct btree *b, *n; + + mutex_lock(&bc->lock); + c->btree_cache.pinned_nodes_mask[0] = 0; + c->btree_cache.pinned_nodes_mask[1] = 0; + + list_for_each_entry_safe(b, n, &bc->live[1].list, list) { + clear_btree_node_pinned(b); + list_move(&b->list, &bc->live[0].list); + bc->live[0].nr++; + bc->live[1].nr--; + } + + mutex_unlock(&bc->lock); +} + +/* Btree in memory cache - hash table */ + +void __bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b) +{ + lockdep_assert_held(&bc->lock); + + int ret = rhashtable_remove_fast(&bc->table, &b->hash, bch_btree_cache_params); + BUG_ON(ret); + + /* Cause future lookups for this node to fail: */ + b->hash_val = 0; + + if (b->c.btree_id < BTREE_ID_NR) + --bc->nr_by_btree[b->c.btree_id]; + --bc->live[btree_node_pinned(b)].nr; + list_del_init(&b->list); +} + +void bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b) +{ + __bch2_btree_node_hash_remove(bc, b); + __bch2_btree_node_to_freelist(bc, b); +} + +int __bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b) +{ + BUG_ON(!list_empty(&b->list)); + BUG_ON(b->hash_val); + + b->hash_val = btree_ptr_hash_val(&b->key); + int ret = rhashtable_lookup_insert_fast(&bc->table, &b->hash, + bch_btree_cache_params); + if (ret) + return ret; + + if (b->c.btree_id < BTREE_ID_NR) + bc->nr_by_btree[b->c.btree_id]++; + + bool p = __btree_node_pinned(bc, b); + mod_bit(BTREE_NODE_pinned, &b->flags, p); + + list_add_tail(&b->list, &bc->live[p].list); + bc->live[p].nr++; + return 0; +} + +int bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b, + unsigned level, enum btree_id id) +{ + b->c.level = level; + b->c.btree_id = id; + + mutex_lock(&bc->lock); + int ret = __bch2_btree_node_hash_insert(bc, b); + mutex_unlock(&bc->lock); + + return ret; +} + +void bch2_btree_node_update_key_early(struct btree_trans *trans, + enum btree_id btree, unsigned level, + struct bkey_s_c old, struct bkey_i *new) +{ + struct bch_fs *c = trans->c; + struct btree *b; + struct bkey_buf tmp; + int ret; + + bch2_bkey_buf_init(&tmp); + bch2_bkey_buf_reassemble(&tmp, c, old); + + b = bch2_btree_node_get_noiter(trans, tmp.k, btree, level, true); + if (!IS_ERR_OR_NULL(b)) { + mutex_lock(&c->btree_cache.lock); + + bch2_btree_node_hash_remove(&c->btree_cache, b); + + bkey_copy(&b->key, new); + ret = __bch2_btree_node_hash_insert(&c->btree_cache, b); + BUG_ON(ret); + + mutex_unlock(&c->btree_cache.lock); + six_unlock_read(&b->c.lock); + } + + bch2_bkey_buf_exit(&tmp, c); +} + +__flatten +static inline struct btree *btree_cache_find(struct btree_cache *bc, + const struct bkey_i *k) +{ + u64 v = btree_ptr_hash_val(k); + + return rhashtable_lookup_fast(&bc->table, &v, bch_btree_cache_params); +} + +/* + * this version is for btree nodes that have already been freed (we're not + * reaping a real btree node) + */ +static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush, bool shrinker_counter) +{ + struct btree_cache *bc = &c->btree_cache; + int ret = 0; + + lockdep_assert_held(&bc->lock); +wait_on_io: + if (b->flags & ((1U << BTREE_NODE_dirty)| + (1U << BTREE_NODE_read_in_flight)| + (1U << BTREE_NODE_write_in_flight))) { + if (!flush) { + if (btree_node_dirty(b)) + BTREE_CACHE_NOT_FREED_INCREMENT(dirty); + else if (btree_node_read_in_flight(b)) + BTREE_CACHE_NOT_FREED_INCREMENT(read_in_flight); + else if (btree_node_write_in_flight(b)) + BTREE_CACHE_NOT_FREED_INCREMENT(write_in_flight); + return -BCH_ERR_ENOMEM_btree_node_reclaim; + } + + /* XXX: waiting on IO with btree cache lock held */ + bch2_btree_node_wait_on_read(b); + bch2_btree_node_wait_on_write(b); + } + + if (!six_trylock_intent(&b->c.lock)) { + BTREE_CACHE_NOT_FREED_INCREMENT(lock_intent); + return -BCH_ERR_ENOMEM_btree_node_reclaim; + } + + if (!six_trylock_write(&b->c.lock)) { + BTREE_CACHE_NOT_FREED_INCREMENT(lock_write); + goto out_unlock_intent; + } + + /* recheck under lock */ + if (b->flags & ((1U << BTREE_NODE_read_in_flight)| + (1U << BTREE_NODE_write_in_flight))) { + if (!flush) { + if (btree_node_read_in_flight(b)) + BTREE_CACHE_NOT_FREED_INCREMENT(read_in_flight); + else if (btree_node_write_in_flight(b)) + BTREE_CACHE_NOT_FREED_INCREMENT(write_in_flight); + goto out_unlock; + } + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); + goto wait_on_io; + } + + if (btree_node_noevict(b)) { + BTREE_CACHE_NOT_FREED_INCREMENT(noevict); + goto out_unlock; + } + if (btree_node_write_blocked(b)) { + BTREE_CACHE_NOT_FREED_INCREMENT(write_blocked); + goto out_unlock; + } + if (btree_node_will_make_reachable(b)) { + BTREE_CACHE_NOT_FREED_INCREMENT(will_make_reachable); + goto out_unlock; + } + + if (btree_node_dirty(b)) { + if (!flush) { + BTREE_CACHE_NOT_FREED_INCREMENT(dirty); + goto out_unlock; + } + /* + * Using the underscore version because we don't want to compact + * bsets after the write, since this node is about to be evicted + * - unless btree verify mode is enabled, since it runs out of + * the post write cleanup: + */ + if (bch2_verify_btree_ondisk) + bch2_btree_node_write(c, b, SIX_LOCK_intent, + BTREE_WRITE_cache_reclaim); + else + __bch2_btree_node_write(c, b, + BTREE_WRITE_cache_reclaim); + + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); + goto wait_on_io; + } +out: + if (b->hash_val && !ret) + trace_and_count(c, btree_cache_reap, c, b); + return ret; +out_unlock: + six_unlock_write(&b->c.lock); +out_unlock_intent: + six_unlock_intent(&b->c.lock); + ret = -BCH_ERR_ENOMEM_btree_node_reclaim; + goto out; +} + +static int btree_node_reclaim(struct bch_fs *c, struct btree *b, bool shrinker_counter) +{ + return __btree_node_reclaim(c, b, false, shrinker_counter); +} + +static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b) +{ + return __btree_node_reclaim(c, b, true, false); +} + +static unsigned long bch2_btree_cache_scan(struct shrinker *shrink, + struct shrink_control *sc) +{ + struct btree_cache_list *list = shrink->private_data; + struct btree_cache *bc = container_of(list, struct btree_cache, live[list->idx]); + struct bch_fs *c = container_of(bc, struct bch_fs, btree_cache); + struct btree *b, *t; + unsigned long nr = sc->nr_to_scan; + unsigned long can_free = 0; + unsigned long freed = 0; + unsigned long touched = 0; + unsigned i, flags; + unsigned long ret = SHRINK_STOP; + bool trigger_writes = atomic_long_read(&bc->nr_dirty) + nr >= list->nr * 3 / 4; + + if (bch2_btree_shrinker_disabled) + return SHRINK_STOP; + + mutex_lock(&bc->lock); + flags = memalloc_nofs_save(); + + /* + * It's _really_ critical that we don't free too many btree nodes - we + * have to always leave ourselves a reserve. The reserve is how we + * guarantee that allocating memory for a new btree node can always + * succeed, so that inserting keys into the btree can always succeed and + * IO can always make forward progress: + */ + can_free = btree_cache_can_free(list); + nr = min_t(unsigned long, nr, can_free); + + i = 0; + list_for_each_entry_safe(b, t, &bc->freeable, list) { + /* + * Leave a few nodes on the freeable list, so that a btree split + * won't have to hit the system allocator: + */ + if (++i <= 3) + continue; + + touched++; + + if (touched >= nr) + goto out; + + if (!btree_node_reclaim(c, b, true)) { + btree_node_data_free(bc, b); + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); + freed++; + bc->nr_freed++; + } + } +restart: + list_for_each_entry_safe(b, t, &list->list, list) { + touched++; + + if (btree_node_accessed(b)) { + clear_btree_node_accessed(b); + bc->not_freed[BCH_BTREE_CACHE_NOT_FREED_access_bit]++; + --touched;; + } else if (!btree_node_reclaim(c, b, true)) { + __bch2_btree_node_hash_remove(bc, b); + __btree_node_data_free(bc, b); + + freed++; + bc->nr_freed++; + + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); + + if (freed == nr) + goto out_rotate; + } else if (trigger_writes && + btree_node_dirty(b) && + !btree_node_will_make_reachable(b) && + !btree_node_write_blocked(b) && + six_trylock_read(&b->c.lock)) { + list_move(&list->list, &b->list); + mutex_unlock(&bc->lock); + __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim); + six_unlock_read(&b->c.lock); + if (touched >= nr) + goto out_nounlock; + mutex_lock(&bc->lock); + goto restart; + } + + if (touched >= nr) + break; + } +out_rotate: + if (&t->list != &list->list) + list_move_tail(&list->list, &t->list); +out: + mutex_unlock(&bc->lock); +out_nounlock: + ret = freed; + memalloc_nofs_restore(flags); + trace_and_count(c, btree_cache_scan, sc->nr_to_scan, can_free, ret); + return ret; +} + +static unsigned long bch2_btree_cache_count(struct shrinker *shrink, + struct shrink_control *sc) +{ + struct btree_cache_list *list = shrink->private_data; + + if (bch2_btree_shrinker_disabled) + return 0; + + return btree_cache_can_free(list); +} + +void bch2_fs_btree_cache_exit(struct bch_fs *c) +{ + struct btree_cache *bc = &c->btree_cache; + struct btree *b, *t; + unsigned long flags; + + shrinker_free(bc->live[1].shrink); + shrinker_free(bc->live[0].shrink); + + /* vfree() can allocate memory: */ + flags = memalloc_nofs_save(); + mutex_lock(&bc->lock); + + if (c->verify_data) + list_move(&c->verify_data->list, &bc->live[0].list); + + kvfree(c->verify_ondisk); + + for (unsigned i = 0; i < btree_id_nr_alive(c); i++) { + struct btree_root *r = bch2_btree_id_root(c, i); + + if (r->b) + list_add(&r->b->list, &bc->live[0].list); + } + + list_for_each_entry_safe(b, t, &bc->live[1].list, list) + bch2_btree_node_hash_remove(bc, b); + list_for_each_entry_safe(b, t, &bc->live[0].list, list) + bch2_btree_node_hash_remove(bc, b); + + list_for_each_entry_safe(b, t, &bc->freeable, list) { + BUG_ON(btree_node_read_in_flight(b) || + btree_node_write_in_flight(b)); + + btree_node_data_free(bc, b); + } + + BUG_ON(!bch2_journal_error(&c->journal) && + atomic_long_read(&c->btree_cache.nr_dirty)); + + list_splice(&bc->freed_pcpu, &bc->freed_nonpcpu); + + list_for_each_entry_safe(b, t, &bc->freed_nonpcpu, list) { + list_del(&b->list); + six_lock_exit(&b->c.lock); + kfree(b); + } + + mutex_unlock(&bc->lock); + memalloc_nofs_restore(flags); + + for (unsigned i = 0; i < ARRAY_SIZE(bc->nr_by_btree); i++) + BUG_ON(bc->nr_by_btree[i]); + BUG_ON(bc->live[0].nr); + BUG_ON(bc->live[1].nr); + BUG_ON(bc->nr_freeable); + + if (bc->table_init_done) + rhashtable_destroy(&bc->table); +} + +int bch2_fs_btree_cache_init(struct bch_fs *c) +{ + struct btree_cache *bc = &c->btree_cache; + struct shrinker *shrink; + unsigned i; + int ret = 0; + + ret = rhashtable_init(&bc->table, &bch_btree_cache_params); + if (ret) + goto err; + + bc->table_init_done = true; + + bch2_recalc_btree_reserve(c); + + for (i = 0; i < bc->nr_reserve; i++) + if (!__bch2_btree_node_mem_alloc(c)) + goto err; + + list_splice_init(&bc->live[0].list, &bc->freeable); + + mutex_init(&c->verify_lock); + + shrink = shrinker_alloc(0, "%s-btree_cache", c->name); + if (!shrink) + goto err; + bc->live[0].shrink = shrink; + shrink->count_objects = bch2_btree_cache_count; + shrink->scan_objects = bch2_btree_cache_scan; + shrink->seeks = 2; + shrink->private_data = &bc->live[0]; + shrinker_register(shrink); + + shrink = shrinker_alloc(0, "%s-btree_cache-pinned", c->name); + if (!shrink) + goto err; + bc->live[1].shrink = shrink; + shrink->count_objects = bch2_btree_cache_count; + shrink->scan_objects = bch2_btree_cache_scan; + shrink->seeks = 8; + shrink->private_data = &bc->live[1]; + shrinker_register(shrink); + + return 0; +err: + return -BCH_ERR_ENOMEM_fs_btree_cache_init; +} + +void bch2_fs_btree_cache_init_early(struct btree_cache *bc) +{ + mutex_init(&bc->lock); + for (unsigned i = 0; i < ARRAY_SIZE(bc->live); i++) { + bc->live[i].idx = i; + INIT_LIST_HEAD(&bc->live[i].list); + } + INIT_LIST_HEAD(&bc->freeable); + INIT_LIST_HEAD(&bc->freed_pcpu); + INIT_LIST_HEAD(&bc->freed_nonpcpu); +} + +/* + * We can only have one thread cannibalizing other cached btree nodes at a time, + * or we'll deadlock. We use an open coded mutex to ensure that, which a + * cannibalize_bucket() will take. This means every time we unlock the root of + * the btree, we need to release this lock if we have it held. + */ +void bch2_btree_cache_cannibalize_unlock(struct btree_trans *trans) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + + if (bc->alloc_lock == current) { + trace_and_count(c, btree_cache_cannibalize_unlock, trans); + bc->alloc_lock = NULL; + closure_wake_up(&bc->alloc_wait); + } +} + +int bch2_btree_cache_cannibalize_lock(struct btree_trans *trans, struct closure *cl) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + struct task_struct *old; + + old = NULL; + if (try_cmpxchg(&bc->alloc_lock, &old, current) || old == current) + goto success; + + if (!cl) { + trace_and_count(c, btree_cache_cannibalize_lock_fail, trans); + return -BCH_ERR_ENOMEM_btree_cache_cannibalize_lock; + } + + closure_wait(&bc->alloc_wait, cl); + + /* Try again, after adding ourselves to waitlist */ + old = NULL; + if (try_cmpxchg(&bc->alloc_lock, &old, current) || old == current) { + /* We raced */ + closure_wake_up(&bc->alloc_wait); + goto success; + } + + trace_and_count(c, btree_cache_cannibalize_lock_fail, trans); + return -BCH_ERR_btree_cache_cannibalize_lock_blocked; + +success: + trace_and_count(c, btree_cache_cannibalize_lock, trans); + return 0; +} + +static struct btree *btree_node_cannibalize(struct bch_fs *c) +{ + struct btree_cache *bc = &c->btree_cache; + struct btree *b; + + for (unsigned i = 0; i < ARRAY_SIZE(bc->live); i++) + list_for_each_entry_reverse(b, &bc->live[i].list, list) + if (!btree_node_reclaim(c, b, false)) + return b; + + while (1) { + for (unsigned i = 0; i < ARRAY_SIZE(bc->live); i++) + list_for_each_entry_reverse(b, &bc->live[i].list, list) + if (!btree_node_write_and_reclaim(c, b)) + return b; + + /* + * Rare case: all nodes were intent-locked. + * Just busy-wait. + */ + WARN_ONCE(1, "btree cache cannibalize failed\n"); + cond_resched(); + } +} + +struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_read_locks) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + struct list_head *freed = pcpu_read_locks + ? &bc->freed_pcpu + : &bc->freed_nonpcpu; + struct btree *b, *b2; + u64 start_time = local_clock(); + + mutex_lock(&bc->lock); + + /* + * We never free struct btree itself, just the memory that holds the on + * disk node. Check the freed list before allocating a new one: + */ + list_for_each_entry(b, freed, list) + if (!btree_node_reclaim(c, b, false)) { + list_del_init(&b->list); + goto got_node; + } + + b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN); + if (!b) { + mutex_unlock(&bc->lock); + bch2_trans_unlock(trans); + b = __btree_node_mem_alloc(c, GFP_KERNEL); + if (!b) + goto err; + mutex_lock(&bc->lock); + } + + bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0); + + BUG_ON(!six_trylock_intent(&b->c.lock)); + BUG_ON(!six_trylock_write(&b->c.lock)); + +got_node: + /* + * btree_free() doesn't free memory; it sticks the node on the end of + * the list. Check if there's any freed nodes there: + */ + list_for_each_entry(b2, &bc->freeable, list) + if (!btree_node_reclaim(c, b2, false)) { + swap(b->data, b2->data); + swap(b->aux_data, b2->aux_data); + + list_del_init(&b2->list); + --bc->nr_freeable; + btree_node_to_freedlist(bc, b2); + mutex_unlock(&bc->lock); + + six_unlock_write(&b2->c.lock); + six_unlock_intent(&b2->c.lock); + goto got_mem; + } + + mutex_unlock(&bc->lock); + + if (btree_node_data_alloc(c, b, GFP_NOWAIT|__GFP_NOWARN)) { + bch2_trans_unlock(trans); + if (btree_node_data_alloc(c, b, GFP_KERNEL|__GFP_NOWARN)) + goto err; + } + +got_mem: + BUG_ON(!list_empty(&b->list)); + BUG_ON(btree_node_hashed(b)); + BUG_ON(btree_node_dirty(b)); + BUG_ON(btree_node_write_in_flight(b)); +out: + b->flags = 0; + b->written = 0; + b->nsets = 0; + b->sib_u64s[0] = 0; + b->sib_u64s[1] = 0; + b->whiteout_u64s = 0; + bch2_btree_keys_init(b); + set_btree_node_accessed(b); + + bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc], + start_time); + + int ret = bch2_trans_relock(trans); + if (unlikely(ret)) { + bch2_btree_node_to_freelist(c, b); + return ERR_PTR(ret); + } + + return b; +err: + mutex_lock(&bc->lock); + + /* Try to cannibalize another cached btree node: */ + if (bc->alloc_lock == current) { + b2 = btree_node_cannibalize(c); + clear_btree_node_just_written(b2); + __bch2_btree_node_hash_remove(bc, b2); + + if (b) { + swap(b->data, b2->data); + swap(b->aux_data, b2->aux_data); + btree_node_to_freedlist(bc, b2); + six_unlock_write(&b2->c.lock); + six_unlock_intent(&b2->c.lock); + } else { + b = b2; + } + + BUG_ON(!list_empty(&b->list)); + mutex_unlock(&bc->lock); + + trace_and_count(c, btree_cache_cannibalize, trans); + goto out; + } + + mutex_unlock(&bc->lock); + return ERR_PTR(-BCH_ERR_ENOMEM_btree_node_mem_alloc); +} + +/* Slowpath, don't want it inlined into btree_iter_traverse() */ +static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans, + struct btree_path *path, + const struct bkey_i *k, + enum btree_id btree_id, + unsigned level, + enum six_lock_type lock_type, + bool sync) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + struct btree *b; + + if (unlikely(level >= BTREE_MAX_DEPTH)) { + int ret = bch2_fs_topology_error(c, "attempting to get btree node at level %u, >= max depth %u", + level, BTREE_MAX_DEPTH); + return ERR_PTR(ret); + } + + if (unlikely(!bkey_is_btree_ptr(&k->k))) { + struct printbuf buf = PRINTBUF; + bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k)); + + int ret = bch2_fs_topology_error(c, "attempting to get btree node with non-btree key %s", buf.buf); + printbuf_exit(&buf); + return ERR_PTR(ret); + } + + if (unlikely(k->k.u64s > BKEY_BTREE_PTR_U64s_MAX)) { + struct printbuf buf = PRINTBUF; + bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k)); + + int ret = bch2_fs_topology_error(c, "attempting to get btree node with too big key %s", buf.buf); + printbuf_exit(&buf); + return ERR_PTR(ret); + } + + /* + * Parent node must be locked, else we could read in a btree node that's + * been freed: + */ + if (path && !bch2_btree_node_relock(trans, path, level + 1)) { + trace_and_count(c, trans_restart_relock_parent_for_fill, trans, _THIS_IP_, path); + return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_relock)); + } + + b = bch2_btree_node_mem_alloc(trans, level != 0); + + if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) { + if (!path) + return b; + + trans->memory_allocation_failure = true; + trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path); + return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail)); + } + + if (IS_ERR(b)) + return b; + + bkey_copy(&b->key, k); + if (bch2_btree_node_hash_insert(bc, b, level, btree_id)) { + /* raced with another fill: */ + + /* mark as unhashed... */ + b->hash_val = 0; + + mutex_lock(&bc->lock); + __bch2_btree_node_to_freelist(bc, b); + mutex_unlock(&bc->lock); + + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); + return NULL; + } + + set_btree_node_read_in_flight(b); + six_unlock_write(&b->c.lock); + + if (path) { + u32 seq = six_lock_seq(&b->c.lock); + + /* Unlock before doing IO: */ + six_unlock_intent(&b->c.lock); + bch2_trans_unlock_noassert(trans); + + bch2_btree_node_read(trans, b, sync); + + int ret = bch2_trans_relock(trans); + if (ret) + return ERR_PTR(ret); + + if (!sync) + return NULL; + + if (!six_relock_type(&b->c.lock, lock_type, seq)) + b = NULL; + } else { + bch2_btree_node_read(trans, b, sync); + if (lock_type == SIX_LOCK_read) + six_lock_downgrade(&b->c.lock); + } + + return b; +} + +static noinline void btree_bad_header(struct bch_fs *c, struct btree *b) +{ + struct printbuf buf = PRINTBUF; + + if (c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_allocations) + return; + + prt_printf(&buf, + "btree node header doesn't match ptr\n" + "btree %s level %u\n" + "ptr: ", + bch2_btree_id_str(b->c.btree_id), b->c.level); + bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key)); + + prt_printf(&buf, "\nheader: btree %s level %llu\n" + "min ", + bch2_btree_id_str(BTREE_NODE_ID(b->data)), + BTREE_NODE_LEVEL(b->data)); + bch2_bpos_to_text(&buf, b->data->min_key); + + prt_printf(&buf, "\nmax "); + bch2_bpos_to_text(&buf, b->data->max_key); + + bch2_fs_topology_error(c, "%s", buf.buf); + + printbuf_exit(&buf); +} + +static inline void btree_check_header(struct bch_fs *c, struct btree *b) +{ + if (b->c.btree_id != BTREE_NODE_ID(b->data) || + b->c.level != BTREE_NODE_LEVEL(b->data) || + !bpos_eq(b->data->max_key, b->key.k.p) || + (b->key.k.type == KEY_TYPE_btree_ptr_v2 && + !bpos_eq(b->data->min_key, + bkey_i_to_btree_ptr_v2(&b->key)->v.min_key))) + btree_bad_header(c, b); +} + +static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path, + const struct bkey_i *k, unsigned level, + enum six_lock_type lock_type, + unsigned long trace_ip) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + struct btree *b; + bool need_relock = false; + int ret; + + EBUG_ON(level >= BTREE_MAX_DEPTH); +retry: + b = btree_cache_find(bc, k); + if (unlikely(!b)) { + /* + * We must have the parent locked to call bch2_btree_node_fill(), + * else we could read in a btree node from disk that's been + * freed: + */ + b = bch2_btree_node_fill(trans, path, k, path->btree_id, + level, lock_type, true); + need_relock = true; + + /* We raced and found the btree node in the cache */ + if (!b) + goto retry; + + if (IS_ERR(b)) + return b; + } else { + if (btree_node_read_locked(path, level + 1)) + btree_node_unlock(trans, path, level + 1); + + ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip); + if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) + return ERR_PTR(ret); + + BUG_ON(ret); + + if (unlikely(b->hash_val != btree_ptr_hash_val(k) || + b->c.level != level || + race_fault())) { + six_unlock_type(&b->c.lock, lock_type); + if (bch2_btree_node_relock(trans, path, level + 1)) + goto retry; + + trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path); + return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused)); + } + + /* avoid atomic set bit if it's not needed: */ + if (!btree_node_accessed(b)) + set_btree_node_accessed(b); + } + + if (unlikely(btree_node_read_in_flight(b))) { + u32 seq = six_lock_seq(&b->c.lock); + + six_unlock_type(&b->c.lock, lock_type); + bch2_trans_unlock(trans); + need_relock = true; + + bch2_btree_node_wait_on_read(b); + + ret = bch2_trans_relock(trans); + if (ret) + return ERR_PTR(ret); + + /* + * should_be_locked is not set on this path yet, so we need to + * relock it specifically: + */ + if (!six_relock_type(&b->c.lock, lock_type, seq)) + goto retry; + } + + if (unlikely(need_relock)) { + ret = bch2_trans_relock(trans) ?: + bch2_btree_path_relock_intent(trans, path); + if (ret) { + six_unlock_type(&b->c.lock, lock_type); + return ERR_PTR(ret); + } + } + + prefetch(b->aux_data); + + for_each_bset(b, t) { + void *p = (u64 *) b->aux_data + t->aux_data_offset; + + prefetch(p + L1_CACHE_BYTES * 0); + prefetch(p + L1_CACHE_BYTES * 1); + prefetch(p + L1_CACHE_BYTES * 2); + } + + if (unlikely(btree_node_read_error(b))) { + six_unlock_type(&b->c.lock, lock_type); + return ERR_PTR(-BCH_ERR_btree_node_read_error); + } + + EBUG_ON(b->c.btree_id != path->btree_id); + EBUG_ON(BTREE_NODE_LEVEL(b->data) != level); + btree_check_header(c, b); + + return b; +} + +/** + * bch2_btree_node_get - find a btree node in the cache and lock it, reading it + * in from disk if necessary. + * + * @trans: btree transaction object + * @path: btree_path being traversed + * @k: pointer to btree node (generally KEY_TYPE_btree_ptr_v2) + * @level: level of btree node being looked up (0 == leaf node) + * @lock_type: SIX_LOCK_read or SIX_LOCK_intent + * @trace_ip: ip of caller of btree iterator code (i.e. caller of bch2_btree_iter_peek()) + * + * The btree node will have either a read or a write lock held, depending on + * the @write parameter. + * + * Returns: btree node or ERR_PTR() + */ +struct btree *bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path, + const struct bkey_i *k, unsigned level, + enum six_lock_type lock_type, + unsigned long trace_ip) +{ + struct bch_fs *c = trans->c; + struct btree *b; + int ret; + + EBUG_ON(level >= BTREE_MAX_DEPTH); + + b = btree_node_mem_ptr(k); + + /* + * Check b->hash_val _before_ calling btree_node_lock() - this might not + * be the node we want anymore, and trying to lock the wrong node could + * cause an unneccessary transaction restart: + */ + if (unlikely(!c->opts.btree_node_mem_ptr_optimization || + !b || + b->hash_val != btree_ptr_hash_val(k))) + return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip); + + if (btree_node_read_locked(path, level + 1)) + btree_node_unlock(trans, path, level + 1); + + ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip); + if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) + return ERR_PTR(ret); + + BUG_ON(ret); + + if (unlikely(b->hash_val != btree_ptr_hash_val(k) || + b->c.level != level || + race_fault())) { + six_unlock_type(&b->c.lock, lock_type); + if (bch2_btree_node_relock(trans, path, level + 1)) + return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip); + + trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path); + return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused)); + } + + if (unlikely(btree_node_read_in_flight(b))) { + six_unlock_type(&b->c.lock, lock_type); + return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip); + } + + prefetch(b->aux_data); + + for_each_bset(b, t) { + void *p = (u64 *) b->aux_data + t->aux_data_offset; + + prefetch(p + L1_CACHE_BYTES * 0); + prefetch(p + L1_CACHE_BYTES * 1); + prefetch(p + L1_CACHE_BYTES * 2); + } + + /* avoid atomic set bit if it's not needed: */ + if (!btree_node_accessed(b)) + set_btree_node_accessed(b); + + if (unlikely(btree_node_read_error(b))) { + six_unlock_type(&b->c.lock, lock_type); + return ERR_PTR(-BCH_ERR_btree_node_read_error); + } + + EBUG_ON(b->c.btree_id != path->btree_id); + EBUG_ON(BTREE_NODE_LEVEL(b->data) != level); + btree_check_header(c, b); + + return b; +} + +struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans, + const struct bkey_i *k, + enum btree_id btree_id, + unsigned level, + bool nofill) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + struct btree *b; + int ret; + + EBUG_ON(level >= BTREE_MAX_DEPTH); + + if (c->opts.btree_node_mem_ptr_optimization) { + b = btree_node_mem_ptr(k); + if (b) + goto lock_node; + } +retry: + b = btree_cache_find(bc, k); + if (unlikely(!b)) { + if (nofill) + goto out; + + b = bch2_btree_node_fill(trans, NULL, k, btree_id, + level, SIX_LOCK_read, true); + + /* We raced and found the btree node in the cache */ + if (!b) + goto retry; + + if (IS_ERR(b) && + !bch2_btree_cache_cannibalize_lock(trans, NULL)) + goto retry; + + if (IS_ERR(b)) + goto out; + } else { +lock_node: + ret = btree_node_lock_nopath(trans, &b->c, SIX_LOCK_read, _THIS_IP_); + if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) + return ERR_PTR(ret); + + BUG_ON(ret); + + if (unlikely(b->hash_val != btree_ptr_hash_val(k) || + b->c.btree_id != btree_id || + b->c.level != level)) { + six_unlock_read(&b->c.lock); + goto retry; + } + } + + /* XXX: waiting on IO with btree locks held: */ + __bch2_btree_node_wait_on_read(b); + + prefetch(b->aux_data); + + for_each_bset(b, t) { + void *p = (u64 *) b->aux_data + t->aux_data_offset; + + prefetch(p + L1_CACHE_BYTES * 0); + prefetch(p + L1_CACHE_BYTES * 1); + prefetch(p + L1_CACHE_BYTES * 2); + } + + /* avoid atomic set bit if it's not needed: */ + if (!btree_node_accessed(b)) + set_btree_node_accessed(b); + + if (unlikely(btree_node_read_error(b))) { + six_unlock_read(&b->c.lock); + b = ERR_PTR(-BCH_ERR_btree_node_read_error); + goto out; + } + + EBUG_ON(b->c.btree_id != btree_id); + EBUG_ON(BTREE_NODE_LEVEL(b->data) != level); + btree_check_header(c, b); +out: + bch2_btree_cache_cannibalize_unlock(trans); + return b; +} + +int bch2_btree_node_prefetch(struct btree_trans *trans, + struct btree_path *path, + const struct bkey_i *k, + enum btree_id btree_id, unsigned level) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + + BUG_ON(path && !btree_node_locked(path, level + 1)); + BUG_ON(level >= BTREE_MAX_DEPTH); + + struct btree *b = btree_cache_find(bc, k); + if (b) + return 0; + + b = bch2_btree_node_fill(trans, path, k, btree_id, + level, SIX_LOCK_read, false); + int ret = PTR_ERR_OR_ZERO(b); + if (ret) + return ret; + if (b) + six_unlock_read(&b->c.lock); + return 0; +} + +void bch2_btree_node_evict(struct btree_trans *trans, const struct bkey_i *k) +{ + struct bch_fs *c = trans->c; + struct btree_cache *bc = &c->btree_cache; + struct btree *b; + + b = btree_cache_find(bc, k); + if (!b) + return; + + BUG_ON(b == btree_node_root(trans->c, b)); +wait_on_io: + /* not allowed to wait on io with btree locks held: */ + + /* XXX we're called from btree_gc which will be holding other btree + * nodes locked + */ + __bch2_btree_node_wait_on_read(b); + __bch2_btree_node_wait_on_write(b); + + btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent); + btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write); + if (unlikely(b->hash_val != btree_ptr_hash_val(k))) + goto out; + + if (btree_node_dirty(b)) { + __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim); + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); + goto wait_on_io; + } + + BUG_ON(btree_node_dirty(b)); + + mutex_lock(&bc->lock); + bch2_btree_node_hash_remove(bc, b); + btree_node_data_free(bc, b); + mutex_unlock(&bc->lock); +out: + six_unlock_write(&b->c.lock); + six_unlock_intent(&b->c.lock); +} + +const char *bch2_btree_id_str(enum btree_id btree) +{ + return btree < BTREE_ID_NR ? __bch2_btree_ids[btree] : "(unknown)"; +} + +void bch2_btree_id_to_text(struct printbuf *out, enum btree_id btree) +{ + if (btree < BTREE_ID_NR) + prt_str(out, __bch2_btree_ids[btree]); + else + prt_printf(out, "(unknown btree %u)", btree); +} + +void bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b) +{ + prt_printf(out, "%s level %u/%u\n ", + bch2_btree_id_str(b->c.btree_id), + b->c.level, + bch2_btree_id_root(c, b->c.btree_id)->level); + bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key)); +} + +void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b) +{ + struct bset_stats stats; + + memset(&stats, 0, sizeof(stats)); + + bch2_btree_keys_stats(b, &stats); + + prt_printf(out, "l %u ", b->c.level); + bch2_bpos_to_text(out, b->data->min_key); + prt_printf(out, " - "); + bch2_bpos_to_text(out, b->data->max_key); + prt_printf(out, ":\n" + " ptrs: "); + bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key)); + prt_newline(out); + + prt_printf(out, + " format: "); + bch2_bkey_format_to_text(out, &b->format); + + prt_printf(out, + " unpack fn len: %u\n" + " bytes used %zu/%zu (%zu%% full)\n" + " sib u64s: %u, %u (merge threshold %u)\n" + " nr packed keys %u\n" + " nr unpacked keys %u\n" + " floats %zu\n" + " failed unpacked %zu\n", + b->unpack_fn_len, + b->nr.live_u64s * sizeof(u64), + btree_buf_bytes(b) - sizeof(struct btree_node), + b->nr.live_u64s * 100 / btree_max_u64s(c), + b->sib_u64s[0], + b->sib_u64s[1], + c->btree_foreground_merge_threshold, + b->nr.packed_keys, + b->nr.unpacked_keys, + stats.floats, + stats.failed); +} + +static void prt_btree_cache_line(struct printbuf *out, const struct bch_fs *c, + const char *label, size_t nr) +{ + prt_printf(out, "%s\t", label); + prt_human_readable_u64(out, nr * c->opts.btree_node_size); + prt_printf(out, " (%zu)\n", nr); +} + +static const char * const bch2_btree_cache_not_freed_reasons_strs[] = { +#define x(n) #n, + BCH_BTREE_CACHE_NOT_FREED_REASONS() +#undef x + NULL +}; + +void bch2_btree_cache_to_text(struct printbuf *out, const struct btree_cache *bc) +{ + struct bch_fs *c = container_of(bc, struct bch_fs, btree_cache); + + if (!out->nr_tabstops) + printbuf_tabstop_push(out, 32); + + prt_btree_cache_line(out, c, "live:", bc->live[0].nr); + prt_btree_cache_line(out, c, "pinned:", bc->live[1].nr); + prt_btree_cache_line(out, c, "freeable:", bc->nr_freeable); + prt_btree_cache_line(out, c, "dirty:", atomic_long_read(&bc->nr_dirty)); + prt_printf(out, "cannibalize lock:\t%p\n", bc->alloc_lock); + prt_newline(out); + + for (unsigned i = 0; i < ARRAY_SIZE(bc->nr_by_btree); i++) + prt_btree_cache_line(out, c, bch2_btree_id_str(i), bc->nr_by_btree[i]); + + prt_newline(out); + prt_printf(out, "freed:\t%zu\n", bc->nr_freed); + prt_printf(out, "not freed:\n"); + + for (unsigned i = 0; i < ARRAY_SIZE(bc->not_freed); i++) + prt_printf(out, " %s\t%llu\n", + bch2_btree_cache_not_freed_reasons_strs[i], bc->not_freed[i]); +} |