1 files changed, 0 insertions, 880 deletions

diff --git a/fs/bcachefs/btree_key_cache.c b/fs/bcachefs/btree_key_cache.c
deleted file mode 100644
index d96188b92db2..000000000000
--- a/fs/bcachefs/btree_key_cache.c
+++ /dev/null
@@ -1,880 +0,0 @@
-// 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,
-	.automatic_shrinking	= true,
-};
-
-static inline void btree_path_cached_set(struct btree_trans *trans, struct btree_path *path,
-					 struct bkey_cached *ck,
-					 enum btree_node_locked_type lock_held)
-{
-	path->l[0].lock_seq	= six_lock_seq(&ck->c.lock);
-	path->l[0].b		= (void *) ck;
-	mark_btree_node_locked(trans, path, 0, lock_held);
-}
-
-__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 bool bkey_cached_evict(struct btree_key_cache *c,
-			      struct bkey_cached *ck)
-{
-	bool ret = !rhashtable_remove_fast(&c->table, &ck->hash,
-				      bch2_btree_key_cache_params);
-	if (ret) {
-		memset(&ck->key, ~0, sizeof(ck->key));
-		atomic_long_dec(&c->nr_keys);
-	}
-
-	return ret;
-}
-
-static void __bkey_cached_free(struct rcu_pending *pending, struct rcu_head *rcu)
-{
-	struct bch_fs *c = container_of(pending->srcu, struct bch_fs, btree_trans_barrier);
-	struct bkey_cached *ck = container_of(rcu, struct bkey_cached, rcu);
-
-	this_cpu_dec(*c->btree_key_cache.nr_pending);
-	kmem_cache_free(bch2_key_cache, ck);
-}
-
-static inline void bkey_cached_free_noassert(struct btree_key_cache *bc,
-				      struct bkey_cached *ck)
-{
-	kfree(ck->k);
-	ck->k		= NULL;
-	ck->u64s	= 0;
-
-	six_unlock_write(&ck->c.lock);
-	six_unlock_intent(&ck->c.lock);
-
-	bool pcpu_readers = ck->c.lock.readers != NULL;
-	rcu_pending_enqueue(&bc->pending[pcpu_readers], &ck->rcu);
-	this_cpu_inc(*bc->nr_pending);
-}
-
-static void bkey_cached_free(struct btree_trans *trans,
-			     struct btree_key_cache *bc,
-			     struct bkey_cached *ck)
-{
-	/*
-	 * we'll hit strange issues in the SRCU code if we aren't holding an
-	 * SRCU read lock...
-	 */
-	EBUG_ON(!trans->srcu_held);
-
-	bkey_cached_free_noassert(bc, ck);
-}
-
-static struct bkey_cached *__bkey_cached_alloc(unsigned key_u64s, gfp_t gfp)
-{
-	gfp |= __GFP_ACCOUNT|__GFP_RECLAIMABLE;
-
-	struct bkey_cached *ck = kmem_cache_zalloc(bch2_key_cache, gfp);
-	if (unlikely(!ck))
-		return NULL;
-	ck->k = kmalloc(key_u64s * sizeof(u64), gfp);
-	if (unlikely(!ck->k)) {
-		kmem_cache_free(bch2_key_cache, ck);
-		return NULL;
-	}
-	ck->u64s = key_u64s;
-	return ck;
-}
-
-static struct bkey_cached *
-bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path, unsigned key_u64s)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_key_cache *bc = &c->btree_key_cache;
-	bool pcpu_readers = btree_uses_pcpu_readers(path->btree_id);
-	int ret;
-
-	struct bkey_cached *ck = container_of_or_null(
-				rcu_pending_dequeue(&bc->pending[pcpu_readers]),
-				struct bkey_cached, rcu);
-	if (ck)
-		goto lock;
-
-	ck = allocate_dropping_locks(trans, ret,
-				     __bkey_cached_alloc(key_u64s, _gfp));
-	if (ret) {
-		if (ck)
-			kfree(ck->k);
-		kmem_cache_free(bch2_key_cache, ck);
-		return ERR_PTR(ret);
-	}
-
-	if (ck) {
-		bch2_btree_lock_init(&ck->c, pcpu_readers ? SIX_LOCK_INIT_PCPU : 0, GFP_KERNEL);
-		ck->c.cached = true;
-		goto lock;
-	}
-
-	ck = container_of_or_null(rcu_pending_dequeue_from_all(&bc->pending[pcpu_readers]),
-				  struct bkey_cached, rcu);
-	if (ck)
-		goto lock;
-lock:
-	six_lock_intent(&ck->c.lock, NULL, NULL);
-	six_lock_write(&ck->c.lock, NULL, NULL);
-	return ck;
-}
-
-static struct bkey_cached *
-bkey_cached_reuse(struct btree_key_cache *c)
-{
-
-	guard(rcu)();
-	struct bucket_table *tbl = rht_dereference_rcu(c->table.tbl, &c->table);
-	struct rhash_head *pos;
-	struct bkey_cached *ck;
-
-	for (unsigned 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)) {
-				if (bkey_cached_evict(c, ck))
-					return ck;
-				six_unlock_write(&ck->c.lock);
-				six_unlock_intent(&ck->c.lock);
-			}
-		}
-	return NULL;
-}
-
-static int btree_key_cache_create(struct btree_trans *trans,
-				  struct btree_path *path,
-				  struct btree_path *ck_path,
-				  struct bkey_s_c k)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_key_cache *bc = &c->btree_key_cache;
-
-	/*
-	 * bch2_varint_decode can read past the end of the buffer by at
-	 * most 7 bytes (it won't be used):
-	 */
-	unsigned key_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:
-	 */
-	key_u64s = min(256U, (key_u64s * 3) / 2);
-	key_u64s = roundup_pow_of_two(key_u64s);
-
-	struct bkey_cached *ck = bkey_cached_alloc(trans, ck_path, key_u64s);
-	int ret = PTR_ERR_OR_ZERO(ck);
-	if (ret)
-		return ret;
-
-	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(ck_path->btree_id));
-			return bch_err_throw(c, ENOMEM_btree_key_cache_create);
-		}
-	}
-
-	ck->c.level		= 0;
-	ck->c.btree_id		= ck_path->btree_id;
-	ck->key.btree_id	= ck_path->btree_id;
-	ck->key.pos		= ck_path->pos;
-	ck->flags		= 1U << BKEY_CACHED_ACCESSED;
-
-	if (unlikely(key_u64s > ck->u64s)) {
-		mark_btree_node_locked_noreset(ck_path, 0, BTREE_NODE_UNLOCKED);
-
-		struct bkey_i *new_k = allocate_dropping_locks(trans, ret,
-				kmalloc(key_u64s * sizeof(u64), _gfp));
-		if (unlikely(!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), key_u64s);
-			ret = bch_err_throw(c, ENOMEM_btree_key_cache_fill);
-		} else if (ret) {
-			kfree(new_k);
-			goto err;
-		}
-
-		kfree(ck->k);
-		ck->k = new_k;
-		ck->u64s = key_u64s;
-	}
-
-	bkey_reassemble(ck->k, k);
-
-	ret = bch2_btree_node_lock_write(trans, path, &path_l(path)->b->c);
-	if (unlikely(ret))
-		goto err;
-
-	ret = rhashtable_lookup_insert_fast(&bc->table, &ck->hash, bch2_btree_key_cache_params);
-
-	bch2_btree_node_unlock_write(trans, path, path_l(path)->b);
-
-	if (unlikely(ret)) /* raced with another fill? */
-		goto err;
-
-	atomic_long_inc(&bc->nr_keys);
-	six_unlock_write(&ck->c.lock);
-
-	enum six_lock_type lock_want = __btree_lock_want(ck_path, 0);
-	if (lock_want == SIX_LOCK_read)
-		six_lock_downgrade(&ck->c.lock);
-	btree_path_cached_set(trans, ck_path, ck, (enum btree_node_locked_type) lock_want);
-	ck_path->uptodate = BTREE_ITER_UPTODATE;
-	return 0;
-err:
-	bkey_cached_free(trans, bc, ck);
-	mark_btree_node_locked_noreset(ck_path, 0, BTREE_NODE_UNLOCKED);
-
-	return ret;
-}
-
-static noinline_for_stack void do_trace_key_cache_fill(struct btree_trans *trans,
-						       struct btree_path *ck_path,
-						       struct bkey_s_c k)
-{
-	struct printbuf buf = PRINTBUF;
-
-	bch2_bpos_to_text(&buf, ck_path->pos);
-	prt_char(&buf, ' ');
-	bch2_bkey_val_to_text(&buf, trans->c, k);
-	trace_key_cache_fill(trans, buf.buf);
-	printbuf_exit(&buf);
-}
-
-static noinline int btree_key_cache_fill(struct btree_trans *trans,
-					 btree_path_idx_t ck_path_idx,
-					 unsigned flags)
-{
-	struct btree_path *ck_path = trans->paths + ck_path_idx;
-
-	if (flags & BTREE_ITER_cached_nofill) {
-		ck_path->l[0].b = NULL;
-		return 0;
-	}
-
-	struct bch_fs *c = trans->c;
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	int ret;
-
-	bch2_trans_iter_init(trans, &iter, ck_path->btree_id, ck_path->pos,
-			     BTREE_ITER_intent|
-			     BTREE_ITER_key_cache_fill|
-			     BTREE_ITER_cached_nofill);
-	iter.flags &= ~BTREE_ITER_with_journal;
-	k = bch2_btree_iter_peek_slot(trans, &iter);
-	ret = bkey_err(k);
-	if (ret)
-		goto err;
-
-	/* Recheck after btree lookup, before allocating: */
-	ck_path = trans->paths + ck_path_idx;
-	ret = bch2_btree_key_cache_find(c, ck_path->btree_id, ck_path->pos) ? -EEXIST : 0;
-	if (unlikely(ret))
-		goto out;
-
-	ret = btree_key_cache_create(trans, btree_iter_path(trans, &iter), ck_path, k);
-	if (ret)
-		goto err;
-
-	if (trace_key_cache_fill_enabled())
-		do_trace_key_cache_fill(trans, ck_path, k);
-out:
-	/* We're not likely to need this iterator again: */
-	bch2_set_btree_iter_dontneed(trans, &iter);
-err:
-	bch2_trans_iter_exit(trans, &iter);
-	return ret;
-}
-
-static inline int btree_path_traverse_cached_fast(struct btree_trans *trans,
-						  btree_path_idx_t path_idx)
-{
-	struct bch_fs *c = trans->c;
-	struct bkey_cached *ck;
-	struct btree_path *path = trans->paths + path_idx;
-retry:
-	ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
-	if (!ck)
-		return -ENOENT;
-
-	enum six_lock_type lock_want = __btree_lock_want(path, 0);
-
-	int ret = btree_node_lock(trans, path, (void *) ck, 0, lock_want, _THIS_IP_);
-	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;
-	}
-
-	if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
-		set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
-
-	btree_path_cached_set(trans, path, ck, (enum btree_node_locked_type) lock_want);
-	path->uptodate = BTREE_ITER_UPTODATE;
-	return 0;
-}
-
-int bch2_btree_path_traverse_cached(struct btree_trans *trans,
-				    btree_path_idx_t path_idx,
-				    unsigned flags)
-{
-	EBUG_ON(trans->paths[path_idx].level);
-
-	int ret;
-	do {
-		ret = btree_path_traverse_cached_fast(trans, path_idx);
-		if (unlikely(ret == -ENOENT))
-			ret = btree_key_cache_fill(trans, path_idx, flags);
-	} while (ret == -EEXIST);
-
-	struct btree_path *path = trans->paths + path_idx;
-
-	if (unlikely(ret)) {
-		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);
-		}
-	} else {
-		BUG_ON(path->uptodate);
-		BUG_ON(!path->nodes_locked);
-	}
-
-	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(trans, &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;
-	}
-
-	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) ||
-	    !test_bit(JOURNAL_space_low, &c->journal.flags))
-		commit_flags |= BCH_TRANS_COMMIT_no_journal_res;
-
-	struct bkey_s_c btree_k = bch2_btree_iter_peek_slot(trans, &b_iter);
-	ret = bkey_err(btree_k);
-	if (ret)
-		goto err;
-
-	/* * Check that we're not violating cache coherency rules: */
-	BUG_ON(bkey_deleted(btree_k.k));
-
-	ret   = 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);
-err:
-	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,
-			     "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);
-		if (bkey_cached_evict(&c->btree_key_cache, ck)) {
-			bkey_cached_free(trans, &c->btree_key_cache, ck);
-		} else {
-			six_unlock_write(&ck->c.lock);
-			six_unlock_intent(&ck->c.lock);
-		}
-	}
-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);
-
-	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 btree_key_cache *bc = &c->btree_key_cache;
-	struct bkey_cached *ck = (void *) path->l[0].b;
-
-	/*
-	 * 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);
-	}
-
-	bkey_cached_evict(bc, ck);
-	bkey_cached_free(trans, bc, ck);
-
-	mark_btree_node_locked(trans, path, 0, BTREE_NODE_UNLOCKED);
-
-	struct btree_path *path2;
-	unsigned i;
-	trans_for_each_path(trans, path2, i)
-		if (path2->l[0].b == (void *) ck) {
-			/*
-			 * It's safe to clear should_be_locked here because
-			 * we're evicting from the key cache, and we still have
-			 * the underlying btree locked: filling into the key
-			 * cache would require taking a write lock on the btree
-			 * node
-			 */
-			path2->should_be_locked = false;
-			__bch2_btree_path_unlock(trans, path2);
-			path2->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_drop);
-			btree_path_set_dirty(trans, path2, BTREE_ITER_NEED_TRAVERSE);
-		}
-
-	bch2_trans_verify_locks(trans);
-}
-
-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;
-	size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
-	unsigned iter, start;
-	int srcu_idx;
-
-	srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
-	rcu_read_lock();
-
-	tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
-
-	/*
-	 * Scanning is expensive while a rehash is in progress - most elements
-	 * will be on the new hashtable, if it's in progress
-	 *
-	 * A rehash could still start while we're scanning - that's ok, we'll
-	 * still see most elements.
-	 */
-	if (unlikely(tbl->nest)) {
-		rcu_read_unlock();
-		srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
-		return SHRINK_STOP;
-	}
-
-	iter = bc->shrink_iter;
-	if (iter >= tbl->size)
-		iter = 0;
-	start = iter;
-
-	do {
-		struct rhash_head *pos, *next;
-
-		pos = rht_ptr_rcu(&tbl->buckets[iter]);
-
-		while (!rht_is_a_nulls(pos)) {
-			next = rht_dereference_bucket_rcu(pos->next, tbl, iter);
-			ck = container_of(pos, struct bkey_cached, hash);
-
-			if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
-				bc->skipped_dirty++;
-			} else if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags)) {
-				clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
-				bc->skipped_accessed++;
-			} else if (!bkey_cached_lock_for_evict(ck)) {
-				bc->skipped_lock_fail++;
-			} else if (bkey_cached_evict(bc, ck)) {
-				bkey_cached_free_noassert(bc, ck);
-				bc->freed++;
-				freed++;
-			} else {
-				six_unlock_write(&ck->c.lock);
-				six_unlock_intent(&ck->c.lock);
-			}
-
-			scanned++;
-			if (scanned >= nr)
-				goto out;
-
-			pos = next;
-		}
-
-		iter++;
-		if (iter >= tbl->size)
-			iter = 0;
-	} while (scanned < nr && iter != start);
-out:
-	bc->shrink_iter = iter;
-
-	rcu_read_unlock();
-	srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
-
-	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);
-
-	/*
-	 * Avoid hammering our shrinker too much if it's nearly empty - the
-	 * shrinker code doesn't take into account how big our cache is, if it's
-	 * mostly empty but the system is under memory pressure it causes nasty
-	 * lock contention:
-	 */
-	nr -= 128;
-
-	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;
-	struct rhash_head *pos;
-	LIST_HEAD(items);
-	unsigned i;
-
-	shrinker_free(bc->shrink);
-
-	/*
-	 * 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) {
-			if (tbl->nest) {
-				/* wait for in progress rehash */
-				rcu_read_unlock();
-				mutex_lock(&bc->table.mutex);
-				mutex_unlock(&bc->table.mutex);
-				continue;
-			}
-			for (i = 0; i < tbl->size; i++)
-				while (pos = rht_ptr_rcu(&tbl->buckets[i]), !rht_is_a_nulls(pos)) {
-					ck = container_of(pos, struct bkey_cached, hash);
-					BUG_ON(!bkey_cached_evict(bc, ck));
-					kfree(ck->k);
-					kmem_cache_free(bch2_key_cache, ck);
-				}
-		}
-		rcu_read_unlock();
-	}
-
-	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);
-
-	rcu_pending_exit(&bc->pending[0]);
-	rcu_pending_exit(&bc->pending[1]);
-
-	free_percpu(bc->nr_pending);
-}
-
-void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
-{
-}
-
-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;
-
-	bc->nr_pending = alloc_percpu(size_t);
-	if (!bc->nr_pending)
-		return bch_err_throw(c, ENOMEM_fs_btree_cache_init);
-
-	if (rcu_pending_init(&bc->pending[0], &c->btree_trans_barrier, __bkey_cached_free) ||
-	    rcu_pending_init(&bc->pending[1], &c->btree_trans_barrier, __bkey_cached_free))
-		return bch_err_throw(c, ENOMEM_fs_btree_cache_init);
-
-	if (rhashtable_init(&bc->table, &bch2_btree_key_cache_params))
-		return bch_err_throw(c, 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_throw(c, ENOMEM_fs_btree_cache_init);
-	bc->shrink = shrink;
-	shrink->count_objects	= bch2_btree_key_cache_count;
-	shrink->scan_objects	= bch2_btree_key_cache_scan;
-	shrink->batch		= 1 << 14;
-	shrink->seeks		= 0;
-	shrink->private_data	= c;
-	shrinker_register(shrink);
-	return 0;
-}
-
-void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *bc)
-{
-	printbuf_tabstop_push(out, 24);
-	printbuf_tabstop_push(out, 12);
-
-	prt_printf(out, "keys:\t%lu\r\n",		atomic_long_read(&bc->nr_keys));
-	prt_printf(out, "dirty:\t%lu\r\n",		atomic_long_read(&bc->nr_dirty));
-	prt_printf(out, "table size:\t%u\r\n",		bc->table.tbl->size);
-	prt_newline(out);
-	prt_printf(out, "shrinker:\n");
-	prt_printf(out, "requested_to_free:\t%lu\r\n",	bc->requested_to_free);
-	prt_printf(out, "freed:\t%lu\r\n",		bc->freed);
-	prt_printf(out, "skipped_dirty:\t%lu\r\n",	bc->skipped_dirty);
-	prt_printf(out, "skipped_accessed:\t%lu\r\n",	bc->skipped_accessed);
-	prt_printf(out, "skipped_lock_fail:\t%lu\r\n",	bc->skipped_lock_fail);
-	prt_newline(out);
-	prt_printf(out, "pending:\t%zu\r\n",		per_cpu_sum(bc->nr_pending));
-}
-
-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;
-}