--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "btree_cache.h"
+#include "btree_iter.h"
+#include "btree_key_cache.h"
+#include "btree_locking.h"
+#include "btree_update.h"
+#include "errcode.h"
+#include "error.h"
+#include "journal.h"
+#include "journal_reclaim.h"
+#include "trace.h"
+
+#include <linux/sched/mm.h>
+
+static inline bool btree_uses_pcpu_readers(enum btree_id id)
+{
+ return id == BTREE_ID_subvolumes;
+}
+
+static struct kmem_cache *bch2_key_cache;
+
+static int bch2_btree_key_cache_cmp_fn(struct rhashtable_compare_arg *arg,
+ const void *obj)
+{
+ const struct bkey_cached *ck = obj;
+ const struct bkey_cached_key *key = arg->key;
+
+ return ck->key.btree_id != key->btree_id ||
+ !bpos_eq(ck->key.pos, key->pos);
+}
+
+static const struct rhashtable_params bch2_btree_key_cache_params = {
+ .head_offset = offsetof(struct bkey_cached, hash),
+ .key_offset = offsetof(struct bkey_cached, key),
+ .key_len = sizeof(struct bkey_cached_key),
+ .obj_cmpfn = bch2_btree_key_cache_cmp_fn,
+};
+
+__flatten
+inline struct bkey_cached *
+bch2_btree_key_cache_find(struct bch_fs *c, enum btree_id btree_id, struct bpos pos)
+{
+ struct bkey_cached_key key = {
+ .btree_id = btree_id,
+ .pos = pos,
+ };
+
+ return rhashtable_lookup_fast(&c->btree_key_cache.table, &key,
+ bch2_btree_key_cache_params);
+}
+
+static bool bkey_cached_lock_for_evict(struct bkey_cached *ck)
+{
+ if (!six_trylock_intent(&ck->c.lock))
+ return false;
+
+ if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ six_unlock_intent(&ck->c.lock);
+ return false;
+ }
+
+ if (!six_trylock_write(&ck->c.lock)) {
+ six_unlock_intent(&ck->c.lock);
+ return false;
+ }
+
+ return true;
+}
+
+static void bkey_cached_evict(struct btree_key_cache *c,
+ struct bkey_cached *ck)
+{
+ BUG_ON(rhashtable_remove_fast(&c->table, &ck->hash,
+ bch2_btree_key_cache_params));
+ memset(&ck->key, ~0, sizeof(ck->key));
+
+ atomic_long_dec(&c->nr_keys);
+}
+
+static void bkey_cached_free(struct btree_key_cache *bc,
+ struct bkey_cached *ck)
+{
+ struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+
+ BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
+
+ ck->btree_trans_barrier_seq =
+ start_poll_synchronize_srcu(&c->btree_trans_barrier);
+
+ if (ck->c.lock.readers) {
+ list_move_tail(&ck->list, &bc->freed_pcpu);
+ bc->nr_freed_pcpu++;
+ } else {
+ list_move_tail(&ck->list, &bc->freed_nonpcpu);
+ bc->nr_freed_nonpcpu++;
+ }
+ atomic_long_inc(&bc->nr_freed);
+
+ kfree(ck->k);
+ ck->k = NULL;
+ ck->u64s = 0;
+
+ six_unlock_write(&ck->c.lock);
+ six_unlock_intent(&ck->c.lock);
+}
+
+#ifdef __KERNEL__
+static void __bkey_cached_move_to_freelist_ordered(struct btree_key_cache *bc,
+ struct bkey_cached *ck)
+{
+ struct bkey_cached *pos;
+
+ bc->nr_freed_nonpcpu++;
+
+ list_for_each_entry_reverse(pos, &bc->freed_nonpcpu, list) {
+ if (ULONG_CMP_GE(ck->btree_trans_barrier_seq,
+ pos->btree_trans_barrier_seq)) {
+ list_move(&ck->list, &pos->list);
+ return;
+ }
+ }
+
+ list_move(&ck->list, &bc->freed_nonpcpu);
+}
+#endif
+
+static void bkey_cached_move_to_freelist(struct btree_key_cache *bc,
+ struct bkey_cached *ck)
+{
+ BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
+
+ if (!ck->c.lock.readers) {
+#ifdef __KERNEL__
+ struct btree_key_cache_freelist *f;
+ bool freed = false;
+
+ preempt_disable();
+ f = this_cpu_ptr(bc->pcpu_freed);
+
+ if (f->nr < ARRAY_SIZE(f->objs)) {
+ f->objs[f->nr++] = ck;
+ freed = true;
+ }
+ preempt_enable();
+
+ if (!freed) {
+ mutex_lock(&bc->lock);
+ preempt_disable();
+ f = this_cpu_ptr(bc->pcpu_freed);
+
+ while (f->nr > ARRAY_SIZE(f->objs) / 2) {
+ struct bkey_cached *ck2 = f->objs[--f->nr];
+
+ __bkey_cached_move_to_freelist_ordered(bc, ck2);
+ }
+ preempt_enable();
+
+ __bkey_cached_move_to_freelist_ordered(bc, ck);
+ mutex_unlock(&bc->lock);
+ }
+#else
+ mutex_lock(&bc->lock);
+ list_move_tail(&ck->list, &bc->freed_nonpcpu);
+ bc->nr_freed_nonpcpu++;
+ mutex_unlock(&bc->lock);
+#endif
+ } else {
+ mutex_lock(&bc->lock);
+ list_move_tail(&ck->list, &bc->freed_pcpu);
+ mutex_unlock(&bc->lock);
+ }
+}
+
+static void bkey_cached_free_fast(struct btree_key_cache *bc,
+ struct bkey_cached *ck)
+{
+ struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+
+ ck->btree_trans_barrier_seq =
+ start_poll_synchronize_srcu(&c->btree_trans_barrier);
+
+ list_del_init(&ck->list);
+ atomic_long_inc(&bc->nr_freed);
+
+ kfree(ck->k);
+ ck->k = NULL;
+ ck->u64s = 0;
+
+ bkey_cached_move_to_freelist(bc, ck);
+
+ six_unlock_write(&ck->c.lock);
+ six_unlock_intent(&ck->c.lock);
+}
+
+static struct bkey_cached *
+bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
+ bool *was_new)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_key_cache *bc = &c->btree_key_cache;
+ struct bkey_cached *ck = NULL;
+ bool pcpu_readers = btree_uses_pcpu_readers(path->btree_id);
+ int ret;
+
+ if (!pcpu_readers) {
+#ifdef __KERNEL__
+ struct btree_key_cache_freelist *f;
+
+ preempt_disable();
+ f = this_cpu_ptr(bc->pcpu_freed);
+ if (f->nr)
+ ck = f->objs[--f->nr];
+ preempt_enable();
+
+ if (!ck) {
+ mutex_lock(&bc->lock);
+ preempt_disable();
+ f = this_cpu_ptr(bc->pcpu_freed);
+
+ while (!list_empty(&bc->freed_nonpcpu) &&
+ f->nr < ARRAY_SIZE(f->objs) / 2) {
+ ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
+ list_del_init(&ck->list);
+ bc->nr_freed_nonpcpu--;
+ f->objs[f->nr++] = ck;
+ }
+
+ ck = f->nr ? f->objs[--f->nr] : NULL;
+ preempt_enable();
+ mutex_unlock(&bc->lock);
+ }
+#else
+ mutex_lock(&bc->lock);
+ if (!list_empty(&bc->freed_nonpcpu)) {
+ ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
+ list_del_init(&ck->list);
+ bc->nr_freed_nonpcpu--;
+ }
+ mutex_unlock(&bc->lock);
+#endif
+ } else {
+ mutex_lock(&bc->lock);
+ if (!list_empty(&bc->freed_pcpu)) {
+ ck = list_last_entry(&bc->freed_pcpu, struct bkey_cached, list);
+ list_del_init(&ck->list);
+ }
+ mutex_unlock(&bc->lock);
+ }
+
+ if (ck) {
+ ret = btree_node_lock_nopath(trans, &ck->c, SIX_LOCK_intent, _THIS_IP_);
+ if (unlikely(ret)) {
+ bkey_cached_move_to_freelist(bc, ck);
+ return ERR_PTR(ret);
+ }
+
+ path->l[0].b = (void *) ck;
+ path->l[0].lock_seq = six_lock_seq(&ck->c.lock);
+ mark_btree_node_locked(trans, path, 0, BTREE_NODE_INTENT_LOCKED);
+
+ ret = bch2_btree_node_lock_write(trans, path, &ck->c);
+ if (unlikely(ret)) {
+ btree_node_unlock(trans, path, 0);
+ bkey_cached_move_to_freelist(bc, ck);
+ return ERR_PTR(ret);
+ }
+
+ return ck;
+ }
+
+ ck = allocate_dropping_locks(trans, ret,
+ kmem_cache_zalloc(bch2_key_cache, _gfp));
+ if (ret) {
+ kmem_cache_free(bch2_key_cache, ck);
+ return ERR_PTR(ret);
+ }
+
+ if (!ck)
+ return NULL;
+
+ INIT_LIST_HEAD(&ck->list);
+ bch2_btree_lock_init(&ck->c, pcpu_readers ? SIX_LOCK_INIT_PCPU : 0);
+
+ ck->c.cached = true;
+ BUG_ON(!six_trylock_intent(&ck->c.lock));
+ BUG_ON(!six_trylock_write(&ck->c.lock));
+ *was_new = true;
+ return ck;
+}
+
+static struct bkey_cached *
+bkey_cached_reuse(struct btree_key_cache *c)
+{
+ struct bucket_table *tbl;
+ struct rhash_head *pos;
+ struct bkey_cached *ck;
+ unsigned i;
+
+ mutex_lock(&c->lock);
+ rcu_read_lock();
+ tbl = rht_dereference_rcu(c->table.tbl, &c->table);
+ for (i = 0; i < tbl->size; i++)
+ rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
+ if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
+ bkey_cached_lock_for_evict(ck)) {
+ bkey_cached_evict(c, ck);
+ goto out;
+ }
+ }
+ ck = NULL;
+out:
+ rcu_read_unlock();
+ mutex_unlock(&c->lock);
+ return ck;
+}
+
+static struct bkey_cached *
+btree_key_cache_create(struct btree_trans *trans, struct btree_path *path)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_key_cache *bc = &c->btree_key_cache;
+ struct bkey_cached *ck;
+ bool was_new = false;
+
+ ck = bkey_cached_alloc(trans, path, &was_new);
+ if (IS_ERR(ck))
+ return ck;
+
+ if (unlikely(!ck)) {
+ ck = bkey_cached_reuse(bc);
+ if (unlikely(!ck)) {
+ bch_err(c, "error allocating memory for key cache item, btree %s",
+ bch2_btree_id_str(path->btree_id));
+ return ERR_PTR(-BCH_ERR_ENOMEM_btree_key_cache_create);
+ }
+
+ mark_btree_node_locked(trans, path, 0, BTREE_NODE_INTENT_LOCKED);
+ }
+
+ ck->c.level = 0;
+ ck->c.btree_id = path->btree_id;
+ ck->key.btree_id = path->btree_id;
+ ck->key.pos = path->pos;
+ ck->valid = false;
+ ck->flags = 1U << BKEY_CACHED_ACCESSED;
+
+ if (unlikely(rhashtable_lookup_insert_fast(&bc->table,
+ &ck->hash,
+ bch2_btree_key_cache_params))) {
+ /* We raced with another fill: */
+
+ if (likely(was_new)) {
+ six_unlock_write(&ck->c.lock);
+ six_unlock_intent(&ck->c.lock);
+ kfree(ck);
+ } else {
+ bkey_cached_free_fast(bc, ck);
+ }
+
+ mark_btree_node_locked(trans, path, 0, BTREE_NODE_UNLOCKED);
+ return NULL;
+ }
+
+ atomic_long_inc(&bc->nr_keys);
+
+ six_unlock_write(&ck->c.lock);
+
+ return ck;
+}
+
+static int btree_key_cache_fill(struct btree_trans *trans,
+ struct btree_path *ck_path,
+ struct bkey_cached *ck)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ unsigned new_u64s = 0;
+ struct bkey_i *new_k = NULL;
+ int ret;
+
+ k = bch2_bkey_get_iter(trans, &iter, ck->key.btree_id, ck->key.pos,
+ BTREE_ITER_KEY_CACHE_FILL|
+ BTREE_ITER_CACHED_NOFILL);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (!bch2_btree_node_relock(trans, ck_path, 0)) {
+ trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
+ ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_fill);
+ goto err;
+ }
+
+ /*
+ * bch2_varint_decode can read past the end of the buffer by at
+ * most 7 bytes (it won't be used):
+ */
+ new_u64s = k.k->u64s + 1;
+
+ /*
+ * Allocate some extra space so that the transaction commit path is less
+ * likely to have to reallocate, since that requires a transaction
+ * restart:
+ */
+ new_u64s = min(256U, (new_u64s * 3) / 2);
+
+ if (new_u64s > ck->u64s) {
+ new_u64s = roundup_pow_of_two(new_u64s);
+ new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOWAIT|__GFP_NOWARN);
+ if (!new_k) {
+ bch2_trans_unlock(trans);
+
+ new_k = kmalloc(new_u64s * sizeof(u64), GFP_KERNEL);
+ if (!new_k) {
+ bch_err(trans->c, "error allocating memory for key cache key, btree %s u64s %u",
+ bch2_btree_id_str(ck->key.btree_id), new_u64s);
+ ret = -BCH_ERR_ENOMEM_btree_key_cache_fill;
+ goto err;
+ }
+
+ if (!bch2_btree_node_relock(trans, ck_path, 0)) {
+ kfree(new_k);
+ trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
+ ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_fill);
+ goto err;
+ }
+
+ ret = bch2_trans_relock(trans);
+ if (ret) {
+ kfree(new_k);
+ goto err;
+ }
+ }
+ }
+
+ ret = bch2_btree_node_lock_write(trans, ck_path, &ck_path->l[0].b->c);
+ if (ret) {
+ kfree(new_k);
+ goto err;
+ }
+
+ if (new_k) {
+ kfree(ck->k);
+ ck->u64s = new_u64s;
+ ck->k = new_k;
+ }
+
+ bkey_reassemble(ck->k, k);
+ ck->valid = true;
+ bch2_btree_node_unlock_write(trans, ck_path, ck_path->l[0].b);
+
+ /* We're not likely to need this iterator again: */
+ set_btree_iter_dontneed(&iter);
+err:
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static noinline int
+bch2_btree_path_traverse_cached_slowpath(struct btree_trans *trans, struct btree_path *path,
+ unsigned flags)
+{
+ struct bch_fs *c = trans->c;
+ struct bkey_cached *ck;
+ int ret = 0;
+
+ BUG_ON(path->level);
+
+ path->l[1].b = NULL;
+
+ if (bch2_btree_node_relock_notrace(trans, path, 0)) {
+ ck = (void *) path->l[0].b;
+ goto fill;
+ }
+retry:
+ ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
+ if (!ck) {
+ ck = btree_key_cache_create(trans, path);
+ ret = PTR_ERR_OR_ZERO(ck);
+ if (ret)
+ goto err;
+ if (!ck)
+ goto retry;
+
+ mark_btree_node_locked(trans, path, 0, BTREE_NODE_INTENT_LOCKED);
+ path->locks_want = 1;
+ } else {
+ enum six_lock_type lock_want = __btree_lock_want(path, 0);
+
+ ret = btree_node_lock(trans, path, (void *) ck, 0,
+ lock_want, _THIS_IP_);
+ if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+ goto err;
+
+ BUG_ON(ret);
+
+ if (ck->key.btree_id != path->btree_id ||
+ !bpos_eq(ck->key.pos, path->pos)) {
+ six_unlock_type(&ck->c.lock, lock_want);
+ goto retry;
+ }
+
+ mark_btree_node_locked(trans, path, 0,
+ (enum btree_node_locked_type) lock_want);
+ }
+
+ path->l[0].lock_seq = six_lock_seq(&ck->c.lock);
+ path->l[0].b = (void *) ck;
+fill:
+ path->uptodate = BTREE_ITER_UPTODATE;
+
+ if (!ck->valid && !(flags & BTREE_ITER_CACHED_NOFILL)) {
+ /*
+ * Using the underscore version because we haven't set
+ * path->uptodate yet:
+ */
+ if (!path->locks_want &&
+ !__bch2_btree_path_upgrade(trans, path, 1, NULL)) {
+ trace_and_count(trans->c, trans_restart_key_cache_upgrade, trans, _THIS_IP_);
+ ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_upgrade);
+ goto err;
+ }
+
+ ret = btree_key_cache_fill(trans, path, ck);
+ if (ret)
+ goto err;
+
+ ret = bch2_btree_path_relock(trans, path, _THIS_IP_);
+ if (ret)
+ goto err;
+
+ path->uptodate = BTREE_ITER_UPTODATE;
+ }
+
+ if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
+ set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
+
+ BUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
+ BUG_ON(path->uptodate);
+
+ return ret;
+err:
+ path->uptodate = BTREE_ITER_NEED_TRAVERSE;
+ if (!bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
+ btree_node_unlock(trans, path, 0);
+ path->l[0].b = ERR_PTR(ret);
+ }
+ return ret;
+}
+
+int bch2_btree_path_traverse_cached(struct btree_trans *trans, struct btree_path *path,
+ unsigned flags)
+{
+ struct bch_fs *c = trans->c;
+ struct bkey_cached *ck;
+ int ret = 0;
+
+ EBUG_ON(path->level);
+
+ path->l[1].b = NULL;
+
+ if (bch2_btree_node_relock_notrace(trans, path, 0)) {
+ ck = (void *) path->l[0].b;
+ goto fill;
+ }
+retry:
+ ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
+ if (!ck) {
+ return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
+ } else {
+ enum six_lock_type lock_want = __btree_lock_want(path, 0);
+
+ ret = btree_node_lock(trans, path, (void *) ck, 0,
+ lock_want, _THIS_IP_);
+ EBUG_ON(ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart));
+
+ if (ret)
+ return ret;
+
+ if (ck->key.btree_id != path->btree_id ||
+ !bpos_eq(ck->key.pos, path->pos)) {
+ six_unlock_type(&ck->c.lock, lock_want);
+ goto retry;
+ }
+
+ mark_btree_node_locked(trans, path, 0,
+ (enum btree_node_locked_type) lock_want);
+ }
+
+ path->l[0].lock_seq = six_lock_seq(&ck->c.lock);
+ path->l[0].b = (void *) ck;
+fill:
+ if (!ck->valid)
+ return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
+
+ if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
+ set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
+
+ path->uptodate = BTREE_ITER_UPTODATE;
+ EBUG_ON(!ck->valid);
+ EBUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
+
+ return ret;
+}
+
+static int btree_key_cache_flush_pos(struct btree_trans *trans,
+ struct bkey_cached_key key,
+ u64 journal_seq,
+ unsigned commit_flags,
+ bool evict)
+{
+ struct bch_fs *c = trans->c;
+ struct journal *j = &c->journal;
+ struct btree_iter c_iter, b_iter;
+ struct bkey_cached *ck = NULL;
+ int ret;
+
+ bch2_trans_iter_init(trans, &b_iter, key.btree_id, key.pos,
+ BTREE_ITER_SLOTS|
+ BTREE_ITER_INTENT|
+ BTREE_ITER_ALL_SNAPSHOTS);
+ bch2_trans_iter_init(trans, &c_iter, key.btree_id, key.pos,
+ BTREE_ITER_CACHED|
+ BTREE_ITER_INTENT);
+ b_iter.flags &= ~BTREE_ITER_WITH_KEY_CACHE;
+
+ ret = bch2_btree_iter_traverse(&c_iter);
+ if (ret)
+ goto out;
+
+ ck = (void *) btree_iter_path(trans, &c_iter)->l[0].b;
+ if (!ck)
+ goto out;
+
+ if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ if (evict)
+ goto evict;
+ goto out;
+ }
+
+ BUG_ON(!ck->valid);
+
+ if (journal_seq && ck->journal.seq != journal_seq)
+ goto out;
+
+ trans->journal_res.seq = ck->journal.seq;
+
+ /*
+ * If we're at the end of the journal, we really want to free up space
+ * in the journal right away - we don't want to pin that old journal
+ * sequence number with a new btree node write, we want to re-journal
+ * the update
+ */
+ if (ck->journal.seq == journal_last_seq(j))
+ commit_flags |= BCH_WATERMARK_reclaim;
+
+ if (ck->journal.seq != journal_last_seq(j) ||
+ j->watermark == BCH_WATERMARK_stripe)
+ commit_flags |= BCH_TRANS_COMMIT_no_journal_res;
+
+ ret = bch2_btree_iter_traverse(&b_iter) ?:
+ bch2_trans_update(trans, &b_iter, ck->k,
+ BTREE_UPDATE_KEY_CACHE_RECLAIM|
+ BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
+ BTREE_TRIGGER_NORUN) ?:
+ bch2_trans_commit(trans, NULL, NULL,
+ BCH_TRANS_COMMIT_no_check_rw|
+ BCH_TRANS_COMMIT_no_enospc|
+ commit_flags);
+
+ bch2_fs_fatal_err_on(ret &&
+ !bch2_err_matches(ret, BCH_ERR_transaction_restart) &&
+ !bch2_err_matches(ret, BCH_ERR_journal_reclaim_would_deadlock) &&
+ !bch2_journal_error(j), c,
+ "error flushing key cache: %s", bch2_err_str(ret));
+ if (ret)
+ goto out;
+
+ bch2_journal_pin_drop(j, &ck->journal);
+
+ struct btree_path *path = btree_iter_path(trans, &c_iter);
+ BUG_ON(!btree_node_locked(path, 0));
+
+ if (!evict) {
+ if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
+ atomic_long_dec(&c->btree_key_cache.nr_dirty);
+ }
+ } else {
+ struct btree_path *path2;
+ unsigned i;
+evict:
+ trans_for_each_path(trans, path2, i)
+ if (path2 != path)
+ __bch2_btree_path_unlock(trans, path2);
+
+ bch2_btree_node_lock_write_nofail(trans, path, &ck->c);
+
+ if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
+ atomic_long_dec(&c->btree_key_cache.nr_dirty);
+ }
+
+ mark_btree_node_locked_noreset(path, 0, BTREE_NODE_UNLOCKED);
+ bkey_cached_evict(&c->btree_key_cache, ck);
+ bkey_cached_free_fast(&c->btree_key_cache, ck);
+ }
+out:
+ bch2_trans_iter_exit(trans, &b_iter);
+ bch2_trans_iter_exit(trans, &c_iter);
+ return ret;
+}
+
+int bch2_btree_key_cache_journal_flush(struct journal *j,
+ struct journal_entry_pin *pin, u64 seq)
+{
+ struct bch_fs *c = container_of(j, struct bch_fs, journal);
+ struct bkey_cached *ck =
+ container_of(pin, struct bkey_cached, journal);
+ struct bkey_cached_key key;
+ struct btree_trans *trans = bch2_trans_get(c);
+ int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
+ int ret = 0;
+
+ btree_node_lock_nopath_nofail(trans, &ck->c, SIX_LOCK_read);
+ key = ck->key;
+
+ if (ck->journal.seq != seq ||
+ !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ six_unlock_read(&ck->c.lock);
+ goto unlock;
+ }
+
+ if (ck->seq != seq) {
+ bch2_journal_pin_update(&c->journal, ck->seq, &ck->journal,
+ bch2_btree_key_cache_journal_flush);
+ six_unlock_read(&ck->c.lock);
+ goto unlock;
+ }
+ six_unlock_read(&ck->c.lock);
+
+ ret = lockrestart_do(trans,
+ btree_key_cache_flush_pos(trans, key, seq,
+ BCH_TRANS_COMMIT_journal_reclaim, false));
+unlock:
+ srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
+
+ bch2_trans_put(trans);
+ return ret;
+}
+
+bool bch2_btree_insert_key_cached(struct btree_trans *trans,
+ unsigned flags,
+ struct btree_insert_entry *insert_entry)
+{
+ struct bch_fs *c = trans->c;
+ struct bkey_cached *ck = (void *) (trans->paths + insert_entry->path)->l[0].b;
+ struct bkey_i *insert = insert_entry->k;
+ bool kick_reclaim = false;
+
+ BUG_ON(insert->k.u64s > ck->u64s);
+
+ bkey_copy(ck->k, insert);
+ ck->valid = true;
+
+ if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ EBUG_ON(test_bit(BCH_FS_clean_shutdown, &c->flags));
+ set_bit(BKEY_CACHED_DIRTY, &ck->flags);
+ atomic_long_inc(&c->btree_key_cache.nr_dirty);
+
+ if (bch2_nr_btree_keys_need_flush(c))
+ kick_reclaim = true;
+ }
+
+ /*
+ * To minimize lock contention, we only add the journal pin here and
+ * defer pin updates to the flush callback via ->seq. Be careful not to
+ * update ->seq on nojournal commits because we don't want to update the
+ * pin to a seq that doesn't include journal updates on disk. Otherwise
+ * we risk losing the update after a crash.
+ *
+ * The only exception is if the pin is not active in the first place. We
+ * have to add the pin because journal reclaim drives key cache
+ * flushing. The flush callback will not proceed unless ->seq matches
+ * the latest pin, so make sure it starts with a consistent value.
+ */
+ if (!(insert_entry->flags & BTREE_UPDATE_NOJOURNAL) ||
+ !journal_pin_active(&ck->journal)) {
+ ck->seq = trans->journal_res.seq;
+ }
+ bch2_journal_pin_add(&c->journal, trans->journal_res.seq,
+ &ck->journal, bch2_btree_key_cache_journal_flush);
+
+ if (kick_reclaim)
+ journal_reclaim_kick(&c->journal);
+ return true;
+}
+
+void bch2_btree_key_cache_drop(struct btree_trans *trans,
+ struct btree_path *path)
+{
+ struct bch_fs *c = trans->c;
+ struct bkey_cached *ck = (void *) path->l[0].b;
+
+ BUG_ON(!ck->valid);
+
+ /*
+ * We just did an update to the btree, bypassing the key cache: the key
+ * cache key is now stale and must be dropped, even if dirty:
+ */
+ if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+ clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
+ atomic_long_dec(&c->btree_key_cache.nr_dirty);
+ bch2_journal_pin_drop(&c->journal, &ck->journal);
+ }
+
+ ck->valid = false;
+}
+
+static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct bch_fs *c = shrink->private_data;
+ struct btree_key_cache *bc = &c->btree_key_cache;
+ struct bucket_table *tbl;
+ struct bkey_cached *ck, *t;
+ size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
+ unsigned start, flags;
+ int srcu_idx;
+
+ mutex_lock(&bc->lock);
+ srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
+ flags = memalloc_nofs_save();
+
+ /*
+ * Newest freed entries are at the end of the list - once we hit one
+ * that's too new to be freed, we can bail out:
+ */
+ scanned += bc->nr_freed_nonpcpu;
+
+ list_for_each_entry_safe(ck, t, &bc->freed_nonpcpu, list) {
+ if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
+ ck->btree_trans_barrier_seq))
+ break;
+
+ list_del(&ck->list);
+ six_lock_exit(&ck->c.lock);
+ kmem_cache_free(bch2_key_cache, ck);
+ atomic_long_dec(&bc->nr_freed);
+ freed++;
+ bc->nr_freed_nonpcpu--;
+ }
+
+ if (scanned >= nr)
+ goto out;
+
+ scanned += bc->nr_freed_pcpu;
+
+ list_for_each_entry_safe(ck, t, &bc->freed_pcpu, list) {
+ if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
+ ck->btree_trans_barrier_seq))
+ break;
+
+ list_del(&ck->list);
+ six_lock_exit(&ck->c.lock);
+ kmem_cache_free(bch2_key_cache, ck);
+ atomic_long_dec(&bc->nr_freed);
+ freed++;
+ bc->nr_freed_pcpu--;
+ }
+
+ if (scanned >= nr)
+ goto out;
+
+ rcu_read_lock();
+ tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
+ if (bc->shrink_iter >= tbl->size)
+ bc->shrink_iter = 0;
+ start = bc->shrink_iter;
+
+ do {
+ struct rhash_head *pos, *next;
+
+ pos = rht_ptr_rcu(rht_bucket(tbl, bc->shrink_iter));
+
+ while (!rht_is_a_nulls(pos)) {
+ next = rht_dereference_bucket_rcu(pos->next, tbl, bc->shrink_iter);
+ ck = container_of(pos, struct bkey_cached, hash);
+
+ if (test_bit(BKEY_CACHED_DIRTY, &ck->flags))
+ goto next;
+
+ if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
+ clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
+ else if (bkey_cached_lock_for_evict(ck)) {
+ bkey_cached_evict(bc, ck);
+ bkey_cached_free(bc, ck);
+ }
+
+ scanned++;
+ if (scanned >= nr)
+ break;
+next:
+ pos = next;
+ }
+
+ bc->shrink_iter++;
+ if (bc->shrink_iter >= tbl->size)
+ bc->shrink_iter = 0;
+ } while (scanned < nr && bc->shrink_iter != start);
+
+ rcu_read_unlock();
+out:
+ memalloc_nofs_restore(flags);
+ srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
+ mutex_unlock(&bc->lock);
+
+ return freed;
+}
+
+static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct bch_fs *c = shrink->private_data;
+ struct btree_key_cache *bc = &c->btree_key_cache;
+ long nr = atomic_long_read(&bc->nr_keys) -
+ atomic_long_read(&bc->nr_dirty);
+
+ return max(0L, nr);
+}
+
+void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
+{
+ struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+ struct bucket_table *tbl;
+ struct bkey_cached *ck, *n;
+ struct rhash_head *pos;
+ LIST_HEAD(items);
+ unsigned i;
+#ifdef __KERNEL__
+ int cpu;
+#endif
+
+ shrinker_free(bc->shrink);
+
+ mutex_lock(&bc->lock);
+
+ /*
+ * The loop is needed to guard against racing with rehash:
+ */
+ while (atomic_long_read(&bc->nr_keys)) {
+ rcu_read_lock();
+ tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
+ if (tbl)
+ for (i = 0; i < tbl->size; i++)
+ rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
+ bkey_cached_evict(bc, ck);
+ list_add(&ck->list, &items);
+ }
+ rcu_read_unlock();
+ }
+
+#ifdef __KERNEL__
+ for_each_possible_cpu(cpu) {
+ struct btree_key_cache_freelist *f =
+ per_cpu_ptr(bc->pcpu_freed, cpu);
+
+ for (i = 0; i < f->nr; i++) {
+ ck = f->objs[i];
+ list_add(&ck->list, &items);
+ }
+ }
+#endif
+
+ BUG_ON(list_count_nodes(&bc->freed_pcpu) != bc->nr_freed_pcpu);
+ BUG_ON(list_count_nodes(&bc->freed_nonpcpu) != bc->nr_freed_nonpcpu);
+
+ list_splice(&bc->freed_pcpu, &items);
+ list_splice(&bc->freed_nonpcpu, &items);
+
+ mutex_unlock(&bc->lock);
+
+ list_for_each_entry_safe(ck, n, &items, list) {
+ cond_resched();
+
+ list_del(&ck->list);
+ kfree(ck->k);
+ six_lock_exit(&ck->c.lock);
+ kmem_cache_free(bch2_key_cache, ck);
+ }
+
+ if (atomic_long_read(&bc->nr_dirty) &&
+ !bch2_journal_error(&c->journal) &&
+ test_bit(BCH_FS_was_rw, &c->flags))
+ panic("btree key cache shutdown error: nr_dirty nonzero (%li)\n",
+ atomic_long_read(&bc->nr_dirty));
+
+ if (atomic_long_read(&bc->nr_keys))
+ panic("btree key cache shutdown error: nr_keys nonzero (%li)\n",
+ atomic_long_read(&bc->nr_keys));
+
+ if (bc->table_init_done)
+ rhashtable_destroy(&bc->table);
+
+ free_percpu(bc->pcpu_freed);
+}
+
+void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
+{
+ mutex_init(&c->lock);
+ INIT_LIST_HEAD(&c->freed_pcpu);
+ INIT_LIST_HEAD(&c->freed_nonpcpu);
+}
+
+int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
+{
+ struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+ struct shrinker *shrink;
+
+#ifdef __KERNEL__
+ bc->pcpu_freed = alloc_percpu(struct btree_key_cache_freelist);
+ if (!bc->pcpu_freed)
+ return -BCH_ERR_ENOMEM_fs_btree_cache_init;
+#endif
+
+ if (rhashtable_init(&bc->table, &bch2_btree_key_cache_params))
+ return -BCH_ERR_ENOMEM_fs_btree_cache_init;
+
+ bc->table_init_done = true;
+
+ shrink = shrinker_alloc(0, "%s-btree_key_cache", c->name);
+ if (!shrink)
+ return -BCH_ERR_ENOMEM_fs_btree_cache_init;
+ bc->shrink = shrink;
+ shrink->seeks = 0;
+ shrink->count_objects = bch2_btree_key_cache_count;
+ shrink->scan_objects = bch2_btree_key_cache_scan;
+ shrink->private_data = c;
+ shrinker_register(shrink);
+ return 0;
+}
+
+void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
+{
+ prt_printf(out, "nr_freed:\t%lu", atomic_long_read(&c->nr_freed));
+ prt_newline(out);
+ prt_printf(out, "nr_keys:\t%lu", atomic_long_read(&c->nr_keys));
+ prt_newline(out);
+ prt_printf(out, "nr_dirty:\t%lu", atomic_long_read(&c->nr_dirty));
+ prt_newline(out);
+}
+
+void bch2_btree_key_cache_exit(void)
+{
+ kmem_cache_destroy(bch2_key_cache);
+}
+
+int __init bch2_btree_key_cache_init(void)
+{
+ bch2_key_cache = KMEM_CACHE(bkey_cached, SLAB_RECLAIM_ACCOUNT);
+ if (!bch2_key_cache)
+ return -ENOMEM;
+
+ return 0;
+}
projects / bcachefs-tools-debian / blobdiff