X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libbcachefs%2Fbtree_cache.c;h=9b7ea1227069e6d73d53ef15fa0d1ee3afaadd5e;hb=f3f005c76eb5636542a8f5b137bd1904d57e8f86;hp=2ca0a9d8226b1610f3b842f21a1d035f61685728;hpb=c1f55a60c41ca5ab8ed7a0893c3d29f8006da82a;p=bcachefs-tools-debian

diff --git a/libbcachefs/btree_cache.c b/libbcachefs/btree_cache.c
index 2ca0a9d..9b7ea12 100644
--- a/libbcachefs/btree_cache.c
+++ b/libbcachefs/btree_cache.c
@@ -9,16 +9,11 @@
 #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 <trace/events/bcachefs.h>
-
-#define BTREE_CACHE_NOT_FREED_INCREMENT(counter) \
-do {						 \
-	if (shrinker_counter)			 \
-		bc->not_freed_##counter++;	 \
-} while (0)
 
 const char * const bch2_btree_node_flags[] = {
 #define x(f)	#f,
@@ -31,13 +26,15 @@ void bch2_recalc_btree_reserve(struct bch_fs *c)
 {
 	unsigned i, reserve = 16;
 
-	if (!c->btree_roots[0].b)
+	if (!c->btree_roots_known[0].b)
 		reserve += 8;
 
-	for (i = 0; i < BTREE_ID_NR; i++)
-		if (c->btree_roots[i].b)
-			reserve += min_t(unsigned, 1,
-					 c->btree_roots[i].b->c.level) * 8;
+	for (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.reserve = reserve;
 }
@@ -61,10 +58,12 @@ static void btree_node_data_free(struct bch_fs *c, struct btree *b)
 
 	EBUG_ON(btree_node_write_in_flight(b));
 
-	kvpfree(b->data, btree_bytes(c));
+	clear_btree_node_just_written(b);
+
+	kvfree(b->data);
 	b->data = NULL;
 #ifdef __KERNEL__
-	vfree(b->aux_data);
+	kvfree(b->aux_data);
 #else
 	munmap(b->aux_data, btree_aux_data_bytes(b));
 #endif
@@ -95,11 +94,11 @@ static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
 {
 	BUG_ON(b->data || b->aux_data);
 
-	b->data = kvpmalloc(btree_bytes(c), gfp);
+	b->data = kvmalloc(btree_buf_bytes(b), gfp);
 	if (!b->data)
-		return -ENOMEM;
+		return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
 #ifdef __KERNEL__
-	b->aux_data = vmalloc_exec(btree_aux_data_bytes(b), gfp);
+	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,
@@ -108,9 +107,9 @@ static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
 		b->aux_data = NULL;
 #endif
 	if (!b->aux_data) {
-		kvpfree(b->data, btree_bytes(c));
+		kvfree(b->data);
 		b->data = NULL;
-		return -ENOMEM;
+		return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
 	}
 
 	return 0;
@@ -125,13 +124,9 @@ static struct btree *__btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp)
 		return NULL;
 
 	bkey_btree_ptr_init(&b->key);
-	__six_lock_init(&b->c.lock, "b->c.lock", &bch2_btree_node_lock_key);
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	lockdep_set_no_check_recursion(&b->c.lock.dep_map);
-#endif
 	INIT_LIST_HEAD(&b->list);
 	INIT_LIST_HEAD(&b->write_blocked);
-	b->byte_order = ilog2(btree_bytes(c));
+	b->byte_order = ilog2(c->opts.btree_node_size);
 	return b;
 }
 
@@ -149,6 +144,8 @@ struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c)
 		return NULL;
 	}
 
+	bch2_btree_lock_init(&b->c, 0);
+
 	bc->used++;
 	list_add(&b->list, &bc->freeable);
 	return b;
@@ -205,7 +202,7 @@ static inline struct btree *btree_cache_find(struct btree_cache *bc,
  * 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)
+static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush)
 {
 	struct btree_cache *bc = &c->btree_cache;
 	int ret = 0;
@@ -215,64 +212,38 @@ 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 -ENOMEM;
-		}
+		if (!flush)
+			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 -ENOMEM;
-	}
+	if (!six_trylock_intent(&b->c.lock))
+		return -BCH_ERR_ENOMEM_btree_node_reclaim;
 
-	if (!six_trylock_write(&b->c.lock)) {
-		BTREE_CACHE_NOT_FREED_INCREMENT(lock_write);
+	if (!six_trylock_write(&b->c.lock))
 		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);
+		if (!flush)
 			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);
+	if (btree_node_noevict(b) ||
+	    btree_node_write_blocked(b) ||
+	    btree_node_will_make_reachable(b))
 		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);
+		if (!flush)
 			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
@@ -298,25 +269,24 @@ out_unlock:
 	six_unlock_write(&b->c.lock);
 out_unlock_intent:
 	six_unlock_intent(&b->c.lock);
-	ret = -ENOMEM;
+	ret = -BCH_ERR_ENOMEM_btree_node_reclaim;
 	goto out;
 }
 
-static int btree_node_reclaim(struct bch_fs *c, struct btree *b, bool shrinker_counter)
+static int btree_node_reclaim(struct bch_fs *c, struct btree *b)
 {
-	return __btree_node_reclaim(c, b, false, shrinker_counter);
+	return __btree_node_reclaim(c, b, false);
 }
 
 static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
 {
-	return __btree_node_reclaim(c, b, true, false);
+	return __btree_node_reclaim(c, b, true);
 }
 
 static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
 					   struct shrink_control *sc)
 {
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
-					btree_cache.shrink);
+	struct bch_fs *c = shrink->private_data;
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b, *t;
 	unsigned long nr = sc->nr_to_scan;
@@ -358,12 +328,11 @@ static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
 		if (touched >= nr)
 			goto out;
 
-		if (!btree_node_reclaim(c, b, true)) {
+		if (!btree_node_reclaim(c, b)) {
 			btree_node_data_free(c, b);
 			six_unlock_write(&b->c.lock);
 			six_unlock_intent(&b->c.lock);
 			freed++;
-			bc->freed++;
 		}
 	}
 restart:
@@ -372,11 +341,9 @@ restart:
 
 		if (btree_node_accessed(b)) {
 			clear_btree_node_accessed(b);
-			bc->not_freed_access_bit++;
-		} else if (!btree_node_reclaim(c, b, true)) {
+		} else if (!btree_node_reclaim(c, b)) {
 			freed++;
 			btree_node_data_free(c, b);
-			bc->freed++;
 
 			bch2_btree_node_hash_remove(bc, b);
 			six_unlock_write(&b->c.lock);
@@ -417,8 +384,7 @@ out_nounlock:
 static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
 					    struct shrink_control *sc)
 {
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
-					btree_cache.shrink);
+	struct bch_fs *c = shrink->private_data;
 	struct btree_cache *bc = &c->btree_cache;
 
 	if (bch2_btree_shrinker_disabled)
@@ -427,22 +393,13 @@ static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
 	return btree_cache_can_free(bc);
 }
 
-static void bch2_btree_cache_shrinker_to_text(struct printbuf *out, struct shrinker *shrink)
-{
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
-					btree_cache.shrink);
-
-	bch2_btree_cache_to_text(out, &c->btree_cache);
-}
-
 void bch2_fs_btree_cache_exit(struct bch_fs *c)
 {
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b;
 	unsigned i, flags;
 
-	if (bc->shrink.list.next)
-		unregister_shrinker(&bc->shrink);
+	shrinker_free(bc->shrink);
 
 	/* vfree() can allocate memory: */
 	flags = memalloc_nofs_save();
@@ -451,11 +408,14 @@ void bch2_fs_btree_cache_exit(struct bch_fs *c)
 	if (c->verify_data)
 		list_move(&c->verify_data->list, &bc->live);
 
-	kvpfree(c->verify_ondisk, btree_bytes(c));
+	kvfree(c->verify_ondisk);
+
+	for (i = 0; i < btree_id_nr_alive(c); i++) {
+		struct btree_root *r = bch2_btree_id_root(c, i);
 
-	for (i = 0; i < BTREE_ID_NR; i++)
-		if (c->btree_roots[i].b)
-			list_add(&c->btree_roots[i].b->list, &bc->live);
+		if (r->b)
+			list_add(&r->b->list, &bc->live);
+	}
 
 	list_splice(&bc->freeable, &bc->live);
 
@@ -465,21 +425,18 @@ void bch2_fs_btree_cache_exit(struct bch_fs *c)
 		BUG_ON(btree_node_read_in_flight(b) ||
 		       btree_node_write_in_flight(b));
 
-		if (btree_node_dirty(b))
-			bch2_btree_complete_write(c, b, btree_current_write(b));
-		clear_btree_node_dirty_acct(c, b);
-
 		btree_node_data_free(c, b);
 	}
 
-	BUG_ON(atomic_read(&c->btree_cache.dirty));
+	BUG_ON(!bch2_journal_error(&c->journal) &&
+	       atomic_read(&c->btree_cache.dirty));
 
 	list_splice(&bc->freed_pcpu, &bc->freed_nonpcpu);
 
 	while (!list_empty(&bc->freed_nonpcpu)) {
 		b = list_first_entry(&bc->freed_nonpcpu, struct btree, list);
 		list_del(&b->list);
-		six_lock_pcpu_free(&b->c.lock);
+		six_lock_exit(&b->c.lock);
 		kfree(b);
 	}
 
@@ -493,37 +450,39 @@ void bch2_fs_btree_cache_exit(struct bch_fs *c)
 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;
 
-	pr_verbose_init(c->opts, "");
-
 	ret = rhashtable_init(&bc->table, &bch_btree_cache_params);
 	if (ret)
-		goto out;
+		goto err;
 
 	bc->table_init_done = true;
 
 	bch2_recalc_btree_reserve(c);
 
 	for (i = 0; i < bc->reserve; i++)
-		if (!__bch2_btree_node_mem_alloc(c)) {
-			ret = -ENOMEM;
-			goto out;
-		}
+		if (!__bch2_btree_node_mem_alloc(c))
+			goto err;
 
 	list_splice_init(&bc->live, &bc->freeable);
 
 	mutex_init(&c->verify_lock);
 
-	bc->shrink.count_objects	= bch2_btree_cache_count;
-	bc->shrink.scan_objects		= bch2_btree_cache_scan;
-	bc->shrink.to_text		= bch2_btree_cache_shrinker_to_text;
-	bc->shrink.seeks		= 4;
-	ret = register_shrinker(&bc->shrink, "%s/btree_cache", c->name);
-out:
-	pr_verbose_init(c->opts, "ret %i", ret);
-	return ret;
+	shrink = shrinker_alloc(0, "%s-btree_cache", c->name);
+	if (!shrink)
+		goto err;
+	bc->shrink = shrink;
+	shrink->count_objects	= bch2_btree_cache_count;
+	shrink->scan_objects	= bch2_btree_cache_scan;
+	shrink->seeks		= 4;
+	shrink->private_data	= c;
+	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)
@@ -541,19 +500,21 @@ void bch2_fs_btree_cache_init_early(struct btree_cache *bc)
  * 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 bch_fs *c)
+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, c);
+		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 bch_fs *c, struct closure *cl)
+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;
 
@@ -562,8 +523,8 @@ int bch2_btree_cache_cannibalize_lock(struct bch_fs *c, struct closure *cl)
 		goto success;
 
 	if (!cl) {
-		trace_and_count(c, btree_cache_cannibalize_lock_fail, c);
-		return -ENOMEM;
+		trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
+		return -BCH_ERR_ENOMEM_btree_cache_cannibalize_lock;
 	}
 
 	closure_wait(&bc->alloc_wait, cl);
@@ -576,11 +537,11 @@ int bch2_btree_cache_cannibalize_lock(struct bch_fs *c, struct closure *cl)
 		goto success;
 	}
 
-	trace_and_count(c, btree_cache_cannibalize_lock_fail, c);
-	return -EAGAIN;
+	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, c);
+	trace_and_count(c, btree_cache_cannibalize_lock, trans);
 	return 0;
 }
 
@@ -590,7 +551,7 @@ static struct btree *btree_node_cannibalize(struct bch_fs *c)
 	struct btree *b;
 
 	list_for_each_entry_reverse(b, &bc->live, list)
-		if (!btree_node_reclaim(c, b, false))
+		if (!btree_node_reclaim(c, b))
 			return b;
 
 	while (1) {
@@ -607,8 +568,9 @@ static struct btree *btree_node_cannibalize(struct bch_fs *c)
 	}
 }
 
-struct btree *bch2_btree_node_mem_alloc(struct bch_fs *c, bool pcpu_read_locks)
+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
@@ -625,22 +587,22 @@ struct btree *bch2_btree_node_mem_alloc(struct bch_fs *c, bool pcpu_read_locks)
 	 * 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)) {
+		if (!btree_node_reclaim(c, b)) {
 			list_del_init(&b->list);
 			goto got_node;
 		}
 
-	b = __btree_node_mem_alloc(c, __GFP_NOWARN);
+	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);
 	}
 
-	if (pcpu_read_locks)
-		six_lock_pcpu_alloc(&b->c.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));
@@ -651,7 +613,7 @@ got_node:
 	 * 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)) {
+		if (!btree_node_reclaim(c, b2)) {
 			swap(b->data, b2->data);
 			swap(b->aux_data, b2->aux_data);
 			btree_node_to_freedlist(bc, b2);
@@ -662,8 +624,11 @@ got_node:
 
 	mutex_unlock(&bc->lock);
 
-	if (btree_node_data_alloc(c, b, __GFP_NOWARN|GFP_KERNEL))
-		goto err;
+	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;
+	}
 
 	mutex_lock(&bc->lock);
 	bc->used++;
@@ -683,7 +648,7 @@ out:
 	bch2_btree_keys_init(b);
 	set_btree_node_accessed(b);
 
-	bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
+	time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
 			       start_time);
 
 	memalloc_nofs_restore(flags);
@@ -694,6 +659,7 @@ err:
 	/* 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) {
@@ -709,18 +675,17 @@ err:
 
 		mutex_unlock(&bc->lock);
 
-		trace_and_count(c, btree_cache_cannibalize, c);
+		trace_and_count(c, btree_cache_cannibalize, trans);
 		goto out;
 	}
 
 	mutex_unlock(&bc->lock);
 	memalloc_nofs_restore(flags);
-	return ERR_PTR(-ENOMEM);
+	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 bch_fs *c,
-				struct btree_trans *trans,
+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,
@@ -728,6 +693,7 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 				enum six_lock_type lock_type,
 				bool sync)
 {
+	struct bch_fs *c = trans->c;
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b;
 	u32 seq;
@@ -737,14 +703,17 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	 * Parent node must be locked, else we could read in a btree node that's
 	 * been freed:
 	 */
-	if (trans && !bch2_btree_node_relock(trans, path, level + 1)) {
+	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(c, level != 0);
+	b = bch2_btree_node_mem_alloc(trans, level != 0);
+
+	if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) {
+		if (!path)
+			return b;
 
-	if (trans && b == ERR_PTR(-ENOMEM)) {
 		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));
@@ -772,19 +741,19 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	set_btree_node_read_in_flight(b);
 
 	six_unlock_write(&b->c.lock);
-	seq = b->c.lock.state.seq;
+	seq = six_lock_seq(&b->c.lock);
 	six_unlock_intent(&b->c.lock);
 
 	/* Unlock before doing IO: */
-	if (trans && sync)
-		bch2_trans_unlock(trans);
+	if (path && sync)
+		bch2_trans_unlock_noassert(trans);
 
-	bch2_btree_node_read(c, b, sync);
+	bch2_btree_node_read(trans, b, sync);
 
 	if (!sync)
 		return NULL;
 
-	if (trans) {
+	if (path) {
 		int ret = bch2_trans_relock(trans) ?:
 			bch2_btree_path_relock_intent(trans, path);
 		if (ret) {
@@ -794,8 +763,9 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	}
 
 	if (!six_relock_type(&b->c.lock, lock_type, seq)) {
-		if (trans)
-			trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);
+		BUG_ON(!path);
+
+		trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);
 		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_after_fill));
 	}
 
@@ -806,19 +776,19 @@ static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
 {
 	struct printbuf buf = PRINTBUF;
 
-	if (!test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags))
+	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_ids[b->c.btree_id], b->c.level);
+	       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_ids[BTREE_NODE_ID(b->data)],
+	       bch2_btree_id_str(BTREE_NODE_ID(b->data)),
 	       BTREE_NODE_LEVEL(b->data));
 	bch2_bpos_to_text(&buf, b->data->min_key);
 
@@ -833,46 +803,26 @@ 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_cmp(b->data->max_key, b->key.k.p) ||
+	    !bpos_eq(b->data->max_key, b->key.k.p) ||
 	    (b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
-	     bpos_cmp(b->data->min_key,
+	     !bpos_eq(b->data->min_key,
 		      bkey_i_to_btree_ptr_v2(&b->key)->v.min_key)))
 		btree_bad_header(c, b);
 }
 
-/**
- * bch_btree_node_get - find a btree node in the cache and lock it, reading it
- * in from disk if necessary.
- *
- * If IO is necessary and running under generic_make_request, returns -EAGAIN.
- *
- * The btree node will have either a read or a write lock held, depending on
- * the @write parameter.
- */
-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)
+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;
 	struct bset_tree *t;
+	bool need_relock = false;
 	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 (likely(c->opts.btree_node_mem_ptr_optimization &&
-		   b &&
-		   b->hash_val == btree_ptr_hash_val(k)))
-		goto lock_node;
 retry:
 	b = btree_cache_find(bc, k);
 	if (unlikely(!b)) {
@@ -881,8 +831,9 @@ retry:
 		 * else we could read in a btree node from disk that's been
 		 * freed:
 		 */
-		b = bch2_btree_node_fill(c, trans, path, k, path->btree_id,
+		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)
@@ -891,35 +842,6 @@ retry:
 		if (IS_ERR(b))
 			return b;
 	} else {
-lock_node:
-		/*
-		 * There's a potential deadlock with splits and insertions into
-		 * interior nodes we have to avoid:
-		 *
-		 * The other thread might be holding an intent lock on the node
-		 * we want, and they want to update its parent node so they're
-		 * going to upgrade their intent lock on the parent node to a
-		 * write lock.
-		 *
-		 * But if we're holding a read lock on the parent, and we're
-		 * trying to get the intent lock they're holding, we deadlock.
-		 *
-		 * So to avoid this we drop the read locks on parent nodes when
-		 * we're starting to take intent locks - and handle the race.
-		 *
-		 * The race is that they might be about to free the node we
-		 * want, and dropping our read lock on the parent node lets them
-		 * update the parent marking the node we want as freed, and then
-		 * free it:
-		 *
-		 * To guard against this, btree nodes are evicted from the cache
-		 * when they're freed - and b->hash_val is zeroed out, which we
-		 * check for after we lock the node.
-		 *
-		 * Then, bch2_btree_node_relock() on the parent will fail - because
-		 * the parent was modified, when the pointer to the node we want
-		 * was removed - and we'll bail out:
-		 */
 		if (btree_node_read_locked(path, level + 1))
 			btree_node_unlock(trans, path, level + 1);
 
@@ -939,13 +861,18 @@ lock_node:
 			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 = b->c.lock.state.seq;
+		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);
 
@@ -953,19 +880,106 @@ lock_node:
 		 * should_be_locked is not set on this path yet, so we need to
 		 * relock it specifically:
 		 */
-		if (trans) {
-			int ret = bch2_trans_relock(trans) ?:
-				bch2_btree_path_relock_intent(trans, path);
-			if (ret) {
-				BUG_ON(!trans->restarted);
-				return ERR_PTR(ret);
-			}
-		}
-
 		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(-EIO);
+	}
+
+	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;
+	struct bset_tree *t;
+	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) {
@@ -1017,7 +1031,7 @@ retry:
 		if (nofill)
 			goto out;
 
-		b = bch2_btree_node_fill(c, NULL, NULL, k, btree_id,
+		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 */
@@ -1025,14 +1039,14 @@ retry:
 			goto retry;
 
 		if (IS_ERR(b) &&
-		    !bch2_btree_cache_cannibalize_lock(c, NULL))
+		    !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);
+		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);
 
@@ -1073,27 +1087,27 @@ lock_node:
 	EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
 	btree_check_header(c, b);
 out:
-	bch2_btree_cache_cannibalize_unlock(c);
+	bch2_btree_cache_cannibalize_unlock(trans);
 	return b;
 }
 
-int bch2_btree_node_prefetch(struct bch_fs *c,
-			     struct btree_trans *trans,
+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;
 	struct btree *b;
 
-	BUG_ON(trans && !btree_node_locked(path, level + 1));
+	BUG_ON(path && !btree_node_locked(path, level + 1));
 	BUG_ON(level >= BTREE_MAX_DEPTH);
 
 	b = btree_cache_find(bc, k);
 	if (b)
 		return 0;
 
-	b = bch2_btree_node_fill(c, trans, path, k, btree_id,
+	b = bch2_btree_node_fill(trans, path, k, btree_id,
 				 level, SIX_LOCK_read, false);
 	return PTR_ERR_OR_ZERO(b);
 }
@@ -1137,10 +1151,22 @@ wait_on_io:
 	six_unlock_intent(&b->c.lock);
 }
 
-void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
-			     struct btree *b)
+const char *bch2_btree_id_str(enum btree_id btree)
+{
+	return btree < BTREE_ID_NR ? __bch2_btree_ids[btree] : "(unknown)";
+}
+
+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)
 {
-	const struct bkey_format *f = &b->format;
 	struct bset_stats stats;
 
 	memset(&stats, 0, sizeof(stats));
@@ -1154,9 +1180,13 @@ void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
 	prt_printf(out, ":\n"
 	       "    ptrs: ");
 	bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key));
+	prt_newline(out);
 
-	prt_printf(out, "\n"
-	       "    format: u64s %u fields %u %u %u %u %u\n"
+	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"
@@ -1164,15 +1194,9 @@ void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
 	       "    nr unpacked keys %u\n"
 	       "    floats %zu\n"
 	       "    failed unpacked %zu\n",
-	       f->key_u64s,
-	       f->bits_per_field[0],
-	       f->bits_per_field[1],
-	       f->bits_per_field[2],
-	       f->bits_per_field[3],
-	       f->bits_per_field[4],
 	       b->unpack_fn_len,
 	       b->nr.live_u64s * sizeof(u64),
-	       btree_bytes(c) - sizeof(struct btree_node),
+	       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],
@@ -1183,21 +1207,9 @@ void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
 	       stats.failed);
 }
 
-void bch2_btree_cache_to_text(struct printbuf *out, struct btree_cache *bc)
+void bch2_btree_cache_to_text(struct printbuf *out, const struct bch_fs *c)
 {
-	prt_printf(out, "nr nodes:\t\t%u\n", bc->used);
-	prt_printf(out, "nr dirty:\t\t%u\n", atomic_read(&bc->dirty));
-	prt_printf(out, "cannibalize lock:\t%p\n", bc->alloc_lock);
-
-	prt_printf(out, "freed:\t\t\t\t%u\n", bc->freed);
-	prt_printf(out, "not freed, dirty:\t\t%u\n", bc->not_freed_dirty);
-	prt_printf(out, "not freed, write in flight:\t%u\n", bc->not_freed_write_in_flight);
-	prt_printf(out, "not freed, read in flight:\t%u\n", bc->not_freed_read_in_flight);
-	prt_printf(out, "not freed, lock intent failed:\t%u\n", bc->not_freed_lock_intent);
-	prt_printf(out, "not freed, lock write failed:\t%u\n", bc->not_freed_lock_write);
-	prt_printf(out, "not freed, access bit:\t\t%u\n", bc->not_freed_access_bit);
-	prt_printf(out, "not freed, no evict failed:\t%u\n", bc->not_freed_noevict);
-	prt_printf(out, "not freed, write blocked:\t%u\n", bc->not_freed_write_blocked);
-	prt_printf(out, "not freed, will make reachable:\t%u\n", bc->not_freed_will_make_reachable);
-
+	prt_printf(out, "nr nodes:\t\t%u\n", c->btree_cache.used);
+	prt_printf(out, "nr dirty:\t\t%u\n", atomic_read(&c->btree_cache.dirty));
+	prt_printf(out, "cannibalize lock:\t%p\n", c->btree_cache.alloc_lock);
 }