Update bcachefs sources to 0010403265 bcachefs: Fix spurious alloc errors on forced shutdown

23 files changed, 290 insertions, 402 deletions

diff --git a/.bcachefs_revision b/.bcachefs_revision
index 6ba1c9af..8f42b139 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-021e62a098d9fa7e558ae935180e2fb16bb50a3a
+00104032654027a8f4406a82d28911b243f19d94
diff --git a/Makefile b/Makefile
index cc00ac6e..6999b93a 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,7 @@ PYTEST=pytest-3
 CFLAGS+=-std=gnu89 -O2 -g -MMD -Wall				\
 	-Wno-pointer-sign					\
 	-Wno-zero-length-bounds					\
+	-Wno-stringop-overflow					\
 	-fno-strict-aliasing					\
 	-fno-delete-null-pointer-checks				\
 	-I. -Iinclude -Iraid					\
diff --git a/libbcachefs/btree_iter.c b/libbcachefs/btree_iter.c
index 96cc5394..7a95fcc0 100644
--- a/libbcachefs/btree_iter.c
+++ b/libbcachefs/btree_iter.c
@@ -346,7 +346,7 @@ void bch2_btree_trans_verify_locks(struct btree_trans *trans)
 {
 	struct btree_iter *iter;
 
-	trans_for_each_iter_all(trans, iter)
+	trans_for_each_iter(trans, iter)
 		bch2_btree_iter_verify_locks(iter);
 }
 #else
@@ -2002,110 +2002,37 @@ int bch2_trans_iter_free(struct btree_trans *trans,
 	return bch2_trans_iter_put(trans, iter);
 }
 
-#if 0
-static int bch2_trans_realloc_iters(struct btree_trans *trans,
-				    unsigned new_size)
+noinline __cold
+static void btree_trans_iter_alloc_fail(struct btree_trans *trans)
 {
-	void *p, *new_iters, *new_updates, *new_updates2;
-	size_t iters_bytes;
-	size_t updates_bytes;
-
-	new_size = roundup_pow_of_two(new_size);
-
-	BUG_ON(new_size > BTREE_ITER_MAX);
-
-	if (new_size <= trans->size)
-		return 0;
-
-	BUG_ON(trans->used_mempool);
-
-	bch2_trans_unlock(trans);
 
-	iters_bytes	= sizeof(struct btree_iter) * new_size;
-	updates_bytes	= sizeof(struct btree_insert_entry) * new_size;
-
-	p = kmalloc(iters_bytes +
-		    updates_bytes +
-		    updates_bytes, GFP_NOFS);
-	if (p)
-		goto success;
-
-	p = mempool_alloc(&trans->c->btree_iters_pool, GFP_NOFS);
-	new_size = BTREE_ITER_MAX;
-
-	trans->used_mempool = true;
-success:
-	new_iters	= p; p += iters_bytes;
-	new_updates	= p; p += updates_bytes;
-	new_updates2	= p; p += updates_bytes;
-
-	memcpy(new_iters, trans->iters,
-	       sizeof(struct btree_iter) * trans->nr_iters);
-	memcpy(new_updates, trans->updates,
-	       sizeof(struct btree_insert_entry) * trans->nr_updates);
-	memcpy(new_updates2, trans->updates2,
-	       sizeof(struct btree_insert_entry) * trans->nr_updates2);
-
-	if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG))
-		memset(trans->iters, POISON_FREE,
-		       sizeof(struct btree_iter) * trans->nr_iters +
-		       sizeof(struct btree_insert_entry) * trans->nr_iters);
-
-	kfree(trans->iters);
-
-	trans->iters		= new_iters;
-	trans->updates		= new_updates;
-	trans->updates2		= new_updates2;
-	trans->size		= new_size;
-
-	if (trans->iters_live) {
-		trace_trans_restart_iters_realloced(trans->ip, trans->size);
-		return -EINTR;
-	}
+	struct btree_iter *iter;
 
-	return 0;
+	trans_for_each_iter(trans, iter)
+		pr_err("iter: btree %s pos %llu:%llu%s%s%s %ps",
+		       bch2_btree_ids[iter->btree_id],
+		       iter->pos.inode,
+		       iter->pos.offset,
+		       (trans->iters_live & (1ULL << iter->idx)) ? " live" : "",
+		       (trans->iters_touched & (1ULL << iter->idx)) ? " touched" : "",
+		       iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT ? " keep" : "",
+		       (void *) iter->ip_allocated);
+	panic("trans iter oveflow\n");
 }
-#endif
 
 static struct btree_iter *btree_trans_iter_alloc(struct btree_trans *trans)
 {
-	unsigned idx = __ffs64(~trans->iters_linked);
-
-	if (idx < trans->nr_iters)
-		goto got_slot;
-
-	if (trans->nr_iters == trans->size) {
-		struct btree_iter *iter;
-
-		BUG_ON(trans->size < BTREE_ITER_MAX);
-
-		trans_for_each_iter(trans, iter) {
-			pr_err("iter: btree %s pos %llu:%llu%s%s%s %ps",
-			       bch2_btree_ids[iter->btree_id],
-			       iter->pos.inode,
-			       iter->pos.offset,
-			       (trans->iters_live & (1ULL << iter->idx)) ? " live" : "",
-			       (trans->iters_touched & (1ULL << iter->idx)) ? " touched" : "",
-			       iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT ? " keep" : "",
-			       (void *) iter->ip_allocated);
-		}
+	unsigned idx;
 
-		panic("trans iter oveflow\n");
-#if 0
-		ret = bch2_trans_realloc_iters(trans, trans->size * 2);
-		if (ret)
-			return ERR_PTR(ret);
-#endif
-	}
+	if (unlikely(trans->iters_linked ==
+		     ~((~0ULL << 1) << (BTREE_ITER_MAX - 1))))
+		btree_trans_iter_alloc_fail(trans);
 
-	idx = trans->nr_iters++;
-	BUG_ON(trans->nr_iters > trans->size);
+	idx = __ffs64(~trans->iters_linked);
 
-	trans->iters[idx].idx = idx;
-got_slot:
-	BUG_ON(trans->iters_linked & (1ULL << idx));
-	trans->iters_linked |= 1ULL << idx;
-	trans->iters[idx].flags = 0;
+	trans->iters_linked	|= 1ULL << idx;
+	trans->iters[idx].idx	 = idx;
+	trans->iters[idx].flags	 = 0;
 	return &trans->iters[idx];
 }
 
@@ -2141,8 +2068,6 @@ static struct btree_iter *__btree_trans_get_iter(struct btree_trans *trans,
 {
 	struct btree_iter *iter, *best = NULL;
 
-	BUG_ON(trans->nr_iters > BTREE_ITER_MAX);
-
 	trans_for_each_iter(trans, iter) {
 		if (btree_iter_type(iter) != (flags & BTREE_ITER_TYPE))
 			continue;
@@ -2160,16 +2085,10 @@ static struct btree_iter *__btree_trans_get_iter(struct btree_trans *trans,
 
 	if (!best) {
 		iter = btree_trans_iter_alloc(trans);
-		if (IS_ERR(iter))
-			return iter;
-
 		bch2_btree_iter_init(trans, iter, btree_id, pos, flags);
 	} else if ((trans->iters_live & (1ULL << best->idx)) ||
 		   (best->flags & BTREE_ITER_KEEP_UNTIL_COMMIT)) {
 		iter = btree_trans_iter_alloc(trans);
-		if (IS_ERR(iter))
-			return iter;
-
 		btree_iter_copy(iter, best);
 	} else {
 		iter = best;
@@ -2203,9 +2122,8 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
 	struct btree_iter *iter =
 		__btree_trans_get_iter(trans, btree_id, pos, flags);
 
-	if (!IS_ERR(iter))
-		__bch2_btree_iter_set_pos(iter, pos,
-			btree_node_type_is_extents(btree_id));
+	__bch2_btree_iter_set_pos(iter, pos,
+		btree_node_type_is_extents(btree_id));
 	return iter;
 }
 
@@ -2221,7 +2139,6 @@ struct btree_iter *bch2_trans_get_node_iter(struct btree_trans *trans,
 				       flags|BTREE_ITER_NODES);
 	unsigned i;
 
-	BUG_ON(IS_ERR(iter));
 	BUG_ON(bkey_cmp(iter->pos, pos));
 
 	iter->locks_want = locks_want;
@@ -2241,9 +2158,6 @@ struct btree_iter *__bch2_trans_copy_iter(struct btree_trans *trans,
 	struct btree_iter *iter;
 
 	iter = btree_trans_iter_alloc(trans);
-	if (IS_ERR(iter))
-		return iter;
-
 	btree_iter_copy(iter, src);
 
 	trans->iters_live |= 1ULL << iter->idx;
@@ -2318,7 +2232,6 @@ void bch2_trans_reset(struct btree_trans *trans, unsigned flags)
 
 	trans->iters_touched &= trans->iters_live;
 
-	trans->need_reset		= 0;
 	trans->nr_updates		= 0;
 	trans->nr_updates2		= 0;
 	trans->mem_top			= 0;
@@ -2339,9 +2252,8 @@ void bch2_trans_reset(struct btree_trans *trans, unsigned flags)
 
 static void bch2_trans_alloc_iters(struct btree_trans *trans, struct bch_fs *c)
 {
-	unsigned new_size = BTREE_ITER_MAX;
-	size_t iters_bytes	= sizeof(struct btree_iter) * new_size;
-	size_t updates_bytes	= sizeof(struct btree_insert_entry) * new_size;
+	size_t iters_bytes	= sizeof(struct btree_iter) * BTREE_ITER_MAX;
+	size_t updates_bytes	= sizeof(struct btree_insert_entry) * BTREE_ITER_MAX;
 	void *p = NULL;
 
 	BUG_ON(trans->used_mempool);
@@ -2355,7 +2267,6 @@ static void bch2_trans_alloc_iters(struct btree_trans *trans, struct bch_fs *c)
 	trans->iters		= p; p += iters_bytes;
 	trans->updates		= p; p += updates_bytes;
 	trans->updates2		= p; p += updates_bytes;
-	trans->size		= new_size;
 }
 
 void bch2_trans_init(struct btree_trans *trans, struct bch_fs *c,
diff --git a/libbcachefs/btree_iter.h b/libbcachefs/btree_iter.h
index f7a73619..ee8c4346 100644
--- a/libbcachefs/btree_iter.h
+++ b/libbcachefs/btree_iter.h
@@ -48,21 +48,16 @@ static inline int btree_iter_err(const struct btree_iter *iter)
 
 /* Iterate over iters within a transaction: */
 
-#define trans_for_each_iter_all(_trans, _iter)				\
-	for (_iter = (_trans)->iters;					\
-	     _iter < (_trans)->iters + (_trans)->nr_iters;		\
-	     _iter++)
-
 static inline struct btree_iter *
 __trans_next_iter(struct btree_trans *trans, unsigned idx)
 {
-	EBUG_ON(idx < trans->nr_iters && trans->iters[idx].idx != idx);
-
-	for (; idx < trans->nr_iters; idx++)
-		if (trans->iters_linked & (1ULL << idx))
-			return &trans->iters[idx];
+	u64 l = trans->iters_linked >> idx;
+	if (!l)
+		return NULL;
 
-	return NULL;
+	idx += __ffs64(l);
+	EBUG_ON(trans->iters[idx].idx != idx);
+	return &trans->iters[idx];
 }
 
 #define trans_for_each_iter(_trans, _iter)				\
@@ -240,10 +235,9 @@ static inline int bkey_err(struct bkey_s_c k)
 
 #define for_each_btree_key(_trans, _iter, _btree_id,			\
 			   _start, _flags, _k, _ret)			\
-	for ((_ret) = PTR_ERR_OR_ZERO((_iter) =				\
-			bch2_trans_get_iter((_trans), (_btree_id),	\
-					    (_start), (_flags))) ?:	\
-		      PTR_ERR_OR_ZERO(((_k) =				\
+	for ((_iter) = bch2_trans_get_iter((_trans), (_btree_id),	\
+					   (_start), (_flags)),		\
+	     (_ret) = PTR_ERR_OR_ZERO(((_k) =				\
 			__bch2_btree_iter_peek(_iter, _flags)).k);	\
 	     !_ret && (_k).k;						\
 	     (_ret) = PTR_ERR_OR_ZERO(((_k) =				\
@@ -270,9 +264,7 @@ bch2_trans_get_iter(struct btree_trans *trans, enum btree_id btree_id,
 {
 	struct btree_iter *iter =
 		__bch2_trans_get_iter(trans, btree_id, pos, flags);
-
-	if (!IS_ERR(iter))
-		iter->ip_allocated = _THIS_IP_;
+	iter->ip_allocated = _THIS_IP_;
 	return iter;
 }
 
@@ -284,10 +276,8 @@ bch2_trans_copy_iter(struct btree_trans *trans, struct btree_iter *src)
 	struct btree_iter *iter =
 		__bch2_trans_copy_iter(trans, src);
 
-	if (!IS_ERR(iter))
-		iter->ip_allocated = _THIS_IP_;
+	iter->ip_allocated = _THIS_IP_;
 	return iter;
-
 }
 
 struct btree_iter *bch2_trans_get_node_iter(struct btree_trans *,
diff --git a/libbcachefs/btree_key_cache.c b/libbcachefs/btree_key_cache.c
index a21dc485..244c5dbc 100644
--- a/libbcachefs/btree_key_cache.c
+++ b/libbcachefs/btree_key_cache.c
@@ -169,9 +169,6 @@ static int btree_key_cache_fill(struct btree_trans *trans,
 
 	iter = bch2_trans_get_iter(trans, ck->key.btree_id,
 				   ck->key.pos, BTREE_ITER_SLOTS);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
-
 	k = bch2_btree_iter_peek_slot(iter);
 	ret = bkey_err(k);
 	if (ret) {
@@ -319,24 +316,17 @@ static int btree_key_cache_flush_pos(struct btree_trans *trans,
 	struct bch_fs *c = trans->c;
 	struct journal *j = &c->journal;
 	struct btree_iter *c_iter = NULL, *b_iter = NULL;
-	struct bkey_cached *ck;
+	struct bkey_cached *ck = NULL;
 	int ret;
 
 	b_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 				     BTREE_ITER_SLOTS|
 				     BTREE_ITER_INTENT);
-	ret = PTR_ERR_OR_ZERO(b_iter);
-	if (ret)
-		goto out;
-
 	c_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 				     BTREE_ITER_CACHED|
 				     BTREE_ITER_CACHED_NOFILL|
 				     BTREE_ITER_CACHED_NOCREATE|
 				     BTREE_ITER_INTENT);
-	ret = PTR_ERR_OR_ZERO(c_iter);
-	if (ret)
-		goto out;
 retry:
 	ret = bch2_btree_iter_traverse(c_iter);
 	if (ret)
@@ -367,10 +357,11 @@ err:
 	if (ret == -EINTR)
 		goto retry;
 
-	BUG_ON(ret && !bch2_journal_error(j));
-
-	if (ret)
+	if (ret) {
+		bch2_fs_fatal_err_on(!bch2_journal_error(j), c,
+			"error flushing key cache: %i", ret);
 		goto out;
+	}
 
 	bch2_journal_pin_drop(j, &ck->journal);
 	bch2_journal_preres_put(j, &ck->res);
diff --git a/libbcachefs/btree_types.h b/libbcachefs/btree_types.h
index cf59f122..15af60e9 100644
--- a/libbcachefs/btree_types.h
+++ b/libbcachefs/btree_types.h
@@ -357,20 +357,17 @@ struct btree_trans {
 	unsigned long		ip;
 	int			srcu_idx;
 
-	u64			iters_linked;
-	u64			iters_live;
-	u64			iters_touched;
-
-	u8			nr_iters;
 	u8			nr_updates;
 	u8			nr_updates2;
-	u8			size;
 	unsigned		used_mempool:1;
 	unsigned		error:1;
 	unsigned		nounlock:1;
-	unsigned		need_reset:1;
 	unsigned		in_traverse_all:1;
 
+	u64			iters_linked;
+	u64			iters_live;
+	u64			iters_touched;
+
 	unsigned		mem_top;
 	unsigned		mem_bytes;
 	void			*mem;
diff --git a/libbcachefs/btree_update_interior.c b/libbcachefs/btree_update_interior.c
index 5143896e..edc11c22 100644
--- a/libbcachefs/btree_update_interior.c
+++ b/libbcachefs/btree_update_interior.c
@@ -545,6 +545,19 @@ static void btree_update_nodes_written(struct btree_update *as)
 	int ret;
 
 	/*
+	 * If we're already in an error state, it might be because a btree node
+	 * was never written, and we might be trying to free that same btree
+	 * node here, but it won't have been marked as allocated and we'll see
+	 * spurious disk usage inconsistencies in the transactional part below
+	 * if we don't skip it:
+	 */
+	ret = bch2_journal_error(&c->journal);
+	if (ret)
+		goto err;
+
+	BUG_ON(!journal_pin_active(&as->journal));
+
+	/*
 	 * We did an update to a parent node where the pointers we added pointed
 	 * to child nodes that weren't written yet: now, the child nodes have
 	 * been written so we can write out the update to the interior node.
@@ -567,8 +580,10 @@ static void btree_update_nodes_written(struct btree_update *as)
 			      BTREE_INSERT_JOURNAL_RESERVED,
 			      btree_update_nodes_written_trans(&trans, as));
 	bch2_trans_exit(&trans);
-	BUG_ON(ret && !bch2_journal_error(&c->journal));
 
+	bch2_fs_fatal_err_on(ret && !bch2_journal_error(&c->journal), c,
+			     "error %i in btree_update_nodes_written()", ret);
+err:
 	if (b) {
 		/*
 		 * @b is the node we did the final insert into:
@@ -699,17 +714,7 @@ static void btree_update_reparent(struct btree_update *as,
 	child->b = NULL;
 	child->mode = BTREE_INTERIOR_UPDATING_AS;
 
-	/*
-	 * When we write a new btree root, we have to drop our journal pin
-	 * _before_ the new nodes are technically reachable; see
-	 * btree_update_nodes_written().
-	 *
-	 * This goes for journal pins that are recursively blocked on us - so,
-	 * just transfer the journal pin to the new interior update so
-	 * btree_update_nodes_written() can drop it.
-	 */
 	bch2_journal_pin_copy(&c->journal, &as->journal, &child->journal, NULL);
-	bch2_journal_pin_drop(&c->journal, &child->journal);
 }
 
 static void btree_update_updated_root(struct btree_update *as, struct btree *b)
@@ -956,6 +961,10 @@ bch2_btree_update_start(struct btree_trans *trans, enum btree_id id,
 	if (ret)
 		goto err;
 
+	bch2_journal_pin_add(&c->journal,
+			     atomic64_read(&c->journal.seq),
+			     &as->journal, NULL);
+
 	mutex_lock(&c->btree_interior_update_lock);
 	list_add_tail(&as->list, &c->btree_interior_update_list);
 	mutex_unlock(&c->btree_interior_update_lock);
diff --git a/libbcachefs/btree_update_leaf.c b/libbcachefs/btree_update_leaf.c
index bbc6d512..49685523 100644
--- a/libbcachefs/btree_update_leaf.c
+++ b/libbcachefs/btree_update_leaf.c
@@ -707,7 +707,7 @@ static void bch2_trans_update2(struct btree_trans *trans,
 
 	BUG_ON(iter->uptodate > BTREE_ITER_NEED_PEEK);
 
-	EBUG_ON(trans->nr_updates2 >= trans->nr_iters);
+	EBUG_ON(trans->nr_updates2 >= BTREE_ITER_MAX);
 
 	iter->flags |= BTREE_ITER_KEEP_UNTIL_COMMIT;
 
@@ -740,8 +740,6 @@ static int extent_update_to_keys(struct btree_trans *trans,
 		return 0;
 
 	iter = bch2_trans_copy_iter(trans, orig_iter);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
 
 	iter->flags |= BTREE_ITER_INTENT;
 	__bch2_btree_iter_set_pos(iter, insert->k.p, false);
@@ -760,10 +758,6 @@ static int extent_handle_overwrites(struct btree_trans *trans,
 	int ret = 0;
 
 	iter = bch2_trans_get_iter(trans, btree_id, start, BTREE_ITER_INTENT);
-	ret = PTR_ERR_OR_ZERO(iter);
-	if (ret)
-		return ret;
-
 	k = bch2_btree_iter_peek_with_updates(iter);
 
 	while (k.k && !(ret = bkey_err(k))) {
@@ -772,8 +766,6 @@ static int extent_handle_overwrites(struct btree_trans *trans,
 
 		if (bkey_cmp(bkey_start_pos(k.k), start) < 0) {
 			update_iter = bch2_trans_copy_iter(trans, iter);
-			if ((ret = PTR_ERR_OR_ZERO(update_iter)))
-				goto err;
 
 			update = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
 			if ((ret = PTR_ERR_OR_ZERO(update)))
@@ -789,8 +781,6 @@ static int extent_handle_overwrites(struct btree_trans *trans,
 
 		if (bkey_cmp(k.k->p, end) > 0) {
 			update_iter = bch2_trans_copy_iter(trans, iter);
-			if ((ret = PTR_ERR_OR_ZERO(update_iter)))
-				goto err;
 
 			update = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
 			if ((ret = PTR_ERR_OR_ZERO(update)))
@@ -804,8 +794,6 @@ static int extent_handle_overwrites(struct btree_trans *trans,
 			bch2_trans_iter_put(trans, update_iter);
 		} else {
 			update_iter = bch2_trans_copy_iter(trans, iter);
-			if ((ret = PTR_ERR_OR_ZERO(update_iter)))
-				goto err;
 
 			update = bch2_trans_kmalloc(trans, sizeof(struct bkey));
 			if ((ret = PTR_ERR_OR_ZERO(update)))
@@ -837,8 +825,6 @@ int __bch2_trans_commit(struct btree_trans *trans)
 	unsigned u64s;
 	int ret = 0;
 
-	BUG_ON(trans->need_reset);
-
 	if (!trans->nr_updates)
 		goto out_noupdates;
 
@@ -1031,10 +1017,6 @@ int bch2_trans_update(struct btree_trans *trans, struct btree_iter *iter,
 		 */
 		if (trans->iters_live & (1ULL << i->iter->idx)) {
 			i->iter = bch2_trans_copy_iter(trans, i->iter);
-			if (IS_ERR(i->iter)) {
-				trans->need_reset = true;
-				return PTR_ERR(i->iter);
-			}
 
 			i->iter->flags |= BTREE_ITER_KEEP_UNTIL_COMMIT;
 			bch2_trans_iter_put(trans, i->iter);
@@ -1044,7 +1026,7 @@ int bch2_trans_update(struct btree_trans *trans, struct btree_iter *iter,
 		bch2_btree_iter_set_pos(i->iter, n.k->k.p);
 	}
 
-	EBUG_ON(trans->nr_updates >= trans->nr_iters);
+	EBUG_ON(trans->nr_updates >= BTREE_ITER_MAX);
 
 	array_insert_item(trans->updates, trans->nr_updates,
 			  i - trans->updates, n);
@@ -1059,8 +1041,6 @@ int __bch2_btree_insert(struct btree_trans *trans,
 
 	iter = bch2_trans_get_iter(trans, id, bkey_start_pos(&k->k),
 				   BTREE_ITER_INTENT);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
 
 	ret   = bch2_btree_iter_traverse(iter) ?:
 		bch2_trans_update(trans, iter, k, 0);
@@ -1107,9 +1087,6 @@ int bch2_btree_delete_range_trans(struct btree_trans *trans, enum btree_id id,
 	int ret = 0;
 
 	iter = bch2_trans_get_iter(trans, id, start, BTREE_ITER_INTENT);
-	ret = PTR_ERR_OR_ZERO(iter);
-	if (ret)
-		return ret;
 retry:
 	while ((k = bch2_btree_iter_peek(iter)).k &&
 	       !(ret = bkey_err(k)) &&
diff --git a/libbcachefs/buckets.c b/libbcachefs/buckets.c
index f7bdb143..1b1200c5 100644
--- a/libbcachefs/buckets.c
+++ b/libbcachefs/buckets.c
@@ -1576,9 +1576,6 @@ static int trans_get_key(struct btree_trans *trans,
 
 	*iter = bch2_trans_get_iter(trans, btree_id, pos,
 				    flags|BTREE_ITER_INTENT);
-	if (IS_ERR(*iter))
-		return PTR_ERR(*iter);
-
 	*k = __bch2_btree_iter_peek(*iter, flags);
 	ret = bkey_err(*k);
 	if (ret)
@@ -1606,9 +1603,6 @@ static int bch2_trans_start_alloc_update(struct btree_trans *trans, struct btree
 					   BTREE_ITER_CACHED|
 					   BTREE_ITER_CACHED_NOFILL|
 					   BTREE_ITER_INTENT);
-		if (IS_ERR(iter))
-			return PTR_ERR(iter);
-
 		ret = bch2_btree_iter_traverse(iter);
 		if (ret) {
 			bch2_trans_iter_put(trans, iter);
@@ -2044,6 +2038,16 @@ static u64 bch2_recalc_sectors_available(struct bch_fs *c)
 	return avail_factor(__bch2_fs_usage_read_short(c).free);
 }
 
+void __bch2_disk_reservation_put(struct bch_fs *c, struct disk_reservation *res)
+{
+	percpu_down_read(&c->mark_lock);
+	this_cpu_sub(c->usage[0]->online_reserved,
+		     res->sectors);
+	percpu_up_read(&c->mark_lock);
+
+	res->sectors = 0;
+}
+
 #define SECTORS_CACHE	1024
 
 int bch2_disk_reservation_add(struct bch_fs *c, struct disk_reservation *res,
diff --git a/libbcachefs/buckets.h b/libbcachefs/buckets.h
index 856dc5a8..a3873bec 100644
--- a/libbcachefs/buckets.h
+++ b/libbcachefs/buckets.h
@@ -272,11 +272,13 @@ void bch2_trans_fs_usage_apply(struct btree_trans *, struct bch_fs_usage *);
 
 /* disk reservations: */
 
+void __bch2_disk_reservation_put(struct bch_fs *, struct disk_reservation *);
+
 static inline void bch2_disk_reservation_put(struct bch_fs *c,
 					     struct disk_reservation *res)
 {
-	this_cpu_sub(c->usage[0]->online_reserved, res->sectors);
-	res->sectors = 0;
+	if (res->sectors)
+		__bch2_disk_reservation_put(c, res);
 }
 
 #define BCH_DISK_RESERVATION_NOFAIL		(1 << 0)
diff --git a/libbcachefs/fs-io.c b/libbcachefs/fs-io.c
index 7d193ce4..8e6f7300 100644
--- a/libbcachefs/fs-io.c
+++ b/libbcachefs/fs-io.c
@@ -2474,10 +2474,7 @@ static long bchfs_fcollapse_finsert(struct bch_inode_info *inode,
 	src = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS,
 			POS(inode->v.i_ino, src_start >> 9),
 			BTREE_ITER_INTENT);
-	BUG_ON(IS_ERR_OR_NULL(src));
-
 	dst = bch2_trans_copy_iter(&trans, src);
-	BUG_ON(IS_ERR_OR_NULL(dst));
 
 	while (1) {
 		struct disk_reservation disk_res =
diff --git a/libbcachefs/fsck.c b/libbcachefs/fsck.c
index 09ce6c29..39f872de 100644
--- a/libbcachefs/fsck.c
+++ b/libbcachefs/fsck.c
@@ -230,7 +230,6 @@ static int hash_check_duplicates(struct btree_trans *trans,
 		return 0;
 
 	iter = bch2_trans_copy_iter(trans, h->chain);
-	BUG_ON(IS_ERR(iter));
 
 	for_each_btree_key_continue(iter, 0, k2, ret) {
 		if (bkey_cmp(k2.k->p, k.k->p) >= 0)
@@ -265,10 +264,8 @@ static void hash_set_chain_start(struct btree_trans *trans,
 		hash_stop_chain(trans, h);
 
 	if (!hole) {
-		if (!h->chain) {
+		if (!h->chain)
 			h->chain = bch2_trans_copy_iter(trans, k_iter);
-			BUG_ON(IS_ERR(h->chain));
-		}
 
 		h->chain_end = k.k->p.offset;
 	}
@@ -440,9 +437,6 @@ static int bch2_fix_overlapping_extent(struct btree_trans *trans,
 	bch2_cut_front(cut_at, u);
 
 	u_iter = bch2_trans_copy_iter(trans, iter);
-	ret = PTR_ERR_OR_ZERO(u_iter);
-	if (ret)
-		return ret;
 
 	/*
 	 * We don't want to go through the
@@ -485,7 +479,11 @@ static int check_extents(struct bch_fs *c)
 				   BTREE_ITER_INTENT);
 retry:
 	for_each_btree_key_continue(iter, 0, k, ret) {
-		if (bkey_cmp(prev.k->k.p, bkey_start_pos(k.k)) > 0) {
+		/*
+		 * due to retry errors we might see the same extent twice:
+		 */
+		if (bkey_cmp(prev.k->k.p, k.k->p) &&
+		    bkey_cmp(prev.k->k.p, bkey_start_pos(k.k)) > 0) {
 			char buf1[200];
 			char buf2[200];
 
diff --git a/libbcachefs/inode.c b/libbcachefs/inode.c
index 82099e5a..bf1c7319 100644
--- a/libbcachefs/inode.c
+++ b/libbcachefs/inode.c
@@ -302,9 +302,6 @@ struct btree_iter *bch2_inode_peek(struct btree_trans *trans,
 
 	iter = bch2_trans_get_iter(trans, BTREE_ID_INODES, POS(0, inum),
 				   BTREE_ITER_CACHED|flags);
-	if (IS_ERR(iter))
-		return iter;
-
 	k = bch2_btree_iter_peek_cached(iter);
 	ret = bkey_err(k);
 	if (ret)
@@ -640,9 +637,6 @@ int bch2_inode_find_by_inum_trans(struct btree_trans *trans, u64 inode_nr,
 
 	iter = bch2_trans_get_iter(trans, BTREE_ID_INODES,
 			POS(0, inode_nr), BTREE_ITER_CACHED);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
-
 	k = bch2_btree_iter_peek_cached(iter);
 	ret = bkey_err(k);
 	if (ret)
diff --git a/libbcachefs/io.c b/libbcachefs/io.c
index 21087d11..46856c66 100644
--- a/libbcachefs/io.c
+++ b/libbcachefs/io.c
@@ -198,8 +198,6 @@ static int sum_sector_overwrites(struct btree_trans *trans,
 	*delta = 0;
 
 	iter = bch2_trans_copy_iter(trans, extent_iter);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
 
 	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, old, ret) {
 		if (!may_allocate &&
@@ -1790,9 +1788,6 @@ static int __bch2_rbio_narrow_crcs(struct btree_trans *trans,
 
 	iter = bch2_trans_get_iter(trans, BTREE_ID_EXTENTS, rbio->pos,
 				   BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
-	if ((ret = PTR_ERR_OR_ZERO(iter)))
-		goto out;
-
 	k = bch2_btree_iter_peek_slot(iter);
 	if ((ret = bkey_err(k)))
 		goto out;
@@ -2000,10 +1995,6 @@ int __bch2_read_indirect_extent(struct btree_trans *trans,
 	iter = bch2_trans_get_iter(trans, BTREE_ID_REFLINK,
 				   POS(0, reflink_offset),
 				   BTREE_ITER_SLOTS);
-	ret = PTR_ERR_OR_ZERO(iter);
-	if (ret)
-		return ret;
-
 	k = bch2_btree_iter_peek_slot(iter);
 	ret = bkey_err(k);
 	if (ret)
diff --git a/libbcachefs/journal.c b/libbcachefs/journal.c
index 5874a9ff..dd8db8c0 100644
--- a/libbcachefs/journal.c
+++ b/libbcachefs/journal.c
@@ -553,16 +553,13 @@ int bch2_journal_flush_seq_async(struct journal *j, u64 seq,
 	struct journal_buf *buf;
 	int ret = 0;
 
-	if (seq <= j->err_seq)
-		return -EIO;
-
 	if (seq <= j->seq_ondisk)
 		return 1;
 
 	spin_lock(&j->lock);
 
 	/* Recheck under lock: */
-	if (seq <= j->err_seq) {
+	if (j->err_seq && seq >= j->err_seq) {
 		ret = -EIO;
 		goto out;
 	}
diff --git a/libbcachefs/journal_reclaim.c b/libbcachefs/journal_reclaim.c
index 66f5dcce..beaa39f7 100644
--- a/libbcachefs/journal_reclaim.c
+++ b/libbcachefs/journal_reclaim.c
@@ -320,11 +320,14 @@ void bch2_journal_pin_drop(struct journal *j,
 	spin_unlock(&j->lock);
 }
 
-static void bch2_journal_pin_add_locked(struct journal *j, u64 seq,
-			    struct journal_entry_pin *pin,
-			    journal_pin_flush_fn flush_fn)
+void bch2_journal_pin_set(struct journal *j, u64 seq,
+			  struct journal_entry_pin *pin,
+			  journal_pin_flush_fn flush_fn)
 {
-	struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
+	struct journal_entry_pin_list *pin_list;
+
+	spin_lock(&j->lock);
+	pin_list = journal_seq_pin(j, seq);
 
 	__journal_pin_drop(j, pin);
 
@@ -335,45 +338,6 @@ static void bch2_journal_pin_add_locked(struct journal *j, u64 seq,
 	pin->flush	= flush_fn;
 
 	list_add(&pin->list, flush_fn ? &pin_list->list : &pin_list->flushed);
-}
-
-void __bch2_journal_pin_add(struct journal *j, u64 seq,
-			    struct journal_entry_pin *pin,
-			    journal_pin_flush_fn flush_fn)
-{
-	spin_lock(&j->lock);
-	bch2_journal_pin_add_locked(j, seq, pin, flush_fn);
-	spin_unlock(&j->lock);
-
-	/*
-	 * If the journal is currently full,  we might want to call flush_fn
-	 * immediately:
-	 */
-	journal_wake(j);
-}
-
-void bch2_journal_pin_update(struct journal *j, u64 seq,
-			     struct journal_entry_pin *pin,
-			     journal_pin_flush_fn flush_fn)
-{
-	if (journal_pin_active(pin) && pin->seq < seq)
-		return;
-
-	spin_lock(&j->lock);
-
-	if (pin->seq != seq) {
-		bch2_journal_pin_add_locked(j, seq, pin, flush_fn);
-	} else {
-		struct journal_entry_pin_list *pin_list =
-			journal_seq_pin(j, seq);
-
-		/*
-		 * If the pin is already pinning the right sequence number, it
-		 * still might've already been flushed:
-		 */
-		list_move(&pin->list, &pin_list->list);
-	}
-
 	spin_unlock(&j->lock);
 
 	/*
@@ -383,20 +347,6 @@ void bch2_journal_pin_update(struct journal *j, u64 seq,
 	journal_wake(j);
 }
 
-void bch2_journal_pin_copy(struct journal *j,
-			   struct journal_entry_pin *dst,
-			   struct journal_entry_pin *src,
-			   journal_pin_flush_fn flush_fn)
-{
-	spin_lock(&j->lock);
-
-	if (journal_pin_active(src) &&
-	    (!journal_pin_active(dst) || src->seq < dst->seq))
-		bch2_journal_pin_add_locked(j, src->seq, dst, flush_fn);
-
-	spin_unlock(&j->lock);
-}
-
 /**
  * bch2_journal_pin_flush: ensure journal pin callback is no longer running
  */
diff --git a/libbcachefs/journal_reclaim.h b/libbcachefs/journal_reclaim.h
index bae2c921..e2535504 100644
--- a/libbcachefs/journal_reclaim.h
+++ b/libbcachefs/journal_reclaim.h
@@ -42,25 +42,33 @@ journal_seq_pin(struct journal *j, u64 seq)
 void bch2_journal_pin_put(struct journal *, u64);
 void bch2_journal_pin_drop(struct journal *, struct journal_entry_pin *);
 
-void __bch2_journal_pin_add(struct journal *, u64, struct journal_entry_pin *,
-			    journal_pin_flush_fn);
+void bch2_journal_pin_set(struct journal *, u64, struct journal_entry_pin *,
+			  journal_pin_flush_fn);
 
 static inline void bch2_journal_pin_add(struct journal *j, u64 seq,
 					struct journal_entry_pin *pin,
 					journal_pin_flush_fn flush_fn)
 {
 	if (unlikely(!journal_pin_active(pin) || pin->seq > seq))
-		__bch2_journal_pin_add(j, seq, pin, flush_fn);
+		bch2_journal_pin_set(j, seq, pin, flush_fn);
 }
 
-void bch2_journal_pin_update(struct journal *, u64,
-			     struct journal_entry_pin *,
-			     journal_pin_flush_fn);
+static inline void bch2_journal_pin_copy(struct journal *j,
+					 struct journal_entry_pin *dst,
+					 struct journal_entry_pin *src,
+					 journal_pin_flush_fn flush_fn)
+{
+	if (journal_pin_active(src))
+		bch2_journal_pin_add(j, src->seq, dst, flush_fn);
+}
 
-void bch2_journal_pin_copy(struct journal *,
-			   struct journal_entry_pin *,
-			   struct journal_entry_pin *,
-			   journal_pin_flush_fn);
+static inline void bch2_journal_pin_update(struct journal *j, u64 seq,
+					   struct journal_entry_pin *pin,
+					   journal_pin_flush_fn flush_fn)
+{
+	if (unlikely(!journal_pin_active(pin) || pin->seq < seq))
+		bch2_journal_pin_set(j, seq, pin, flush_fn);
+}
 
 void bch2_journal_pin_flush(struct journal *, struct journal_entry_pin *);
 
diff --git a/libbcachefs/movinggc.c b/libbcachefs/movinggc.c
index 4834f41f..2c5daed5 100644
--- a/libbcachefs/movinggc.c
+++ b/libbcachefs/movinggc.c
@@ -61,7 +61,7 @@ static enum data_cmd copygc_pred(struct bch_fs *c, void *arg,
 	copygc_heap *h = &c->copygc_heap;
 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 	const union bch_extent_entry *entry;
-	struct extent_ptr_decoded p;
+	struct extent_ptr_decoded p = { 0 };
 
 	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 		struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
diff --git a/libbcachefs/recovery.c b/libbcachefs/recovery.c
index 0b3521c9..d24cef2b 100644
--- a/libbcachefs/recovery.c
+++ b/libbcachefs/recovery.c
@@ -187,7 +187,7 @@ void bch2_btree_and_journal_iter_init(struct btree_and_journal_iter *iter,
 {
 	memset(iter, 0, sizeof(*iter));
 
-	iter->btree = bch2_trans_get_iter(trans, id, pos, 0);
+	iter->btree = bch2_trans_get_iter(trans, id, pos, BTREE_ITER_PREFETCH);
 	bch2_journal_iter_init(&iter->journal, journal_keys, id, 0, pos);
 }
 
@@ -443,9 +443,6 @@ retry:
 		bch2_cut_back(atomic_end, split);
 
 		split_iter = bch2_trans_copy_iter(&trans, iter);
-		ret = PTR_ERR_OR_ZERO(split_iter);
-		if (ret)
-			goto err;
 
 		/*
 		 * It's important that we don't go through the
@@ -502,8 +499,6 @@ static int __bch2_journal_replay_key(struct btree_trans *trans,
 	iter = bch2_trans_get_node_iter(trans, id, k->k.p,
 					BTREE_MAX_DEPTH, level,
 					BTREE_ITER_INTENT);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
 
 	/*
 	 * iter->flags & BTREE_ITER_IS_EXTENTS triggers the update path to run
@@ -538,8 +533,7 @@ static int __bch2_alloc_replay_key(struct btree_trans *trans, struct bkey_i *k)
 				   BTREE_ITER_CACHED|
 				   BTREE_ITER_CACHED_NOFILL|
 				   BTREE_ITER_INTENT);
-	ret =   PTR_ERR_OR_ZERO(iter) ?:
-		bch2_trans_update(trans, iter, k, BTREE_TRIGGER_NORUN);
+	ret = bch2_trans_update(trans, iter, k, BTREE_TRIGGER_NORUN);
 	bch2_trans_iter_put(trans, iter);
 	return ret;
 }
diff --git a/libbcachefs/str_hash.h b/libbcachefs/str_hash.h
index dea9b725..1ecf72c9 100644
--- a/libbcachefs/str_hash.h
+++ b/libbcachefs/str_hash.h
@@ -205,8 +205,6 @@ int bch2_hash_needs_whiteout(struct btree_trans *trans,
 	int ret;
 
 	iter = bch2_trans_copy_iter(trans, start);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
 
 	bch2_btree_iter_next_slot(iter);
 
@@ -253,11 +251,8 @@ int bch2_hash_set(struct btree_trans *trans,
 		}
 
 		if (!slot &&
-		    !(flags & BCH_HASH_SET_MUST_REPLACE)) {
+		    !(flags & BCH_HASH_SET_MUST_REPLACE))
 			slot = bch2_trans_copy_iter(trans, iter);
-			if (IS_ERR(slot))
-				return PTR_ERR(slot);
-		}
 
 		if (k.k->type != KEY_TYPE_whiteout)
 			goto not_found;
diff --git a/libbcachefs/sysfs.c b/libbcachefs/sysfs.c
index 900eda88..cc13fc25 100644
--- a/libbcachefs/sysfs.c
+++ b/libbcachefs/sysfs.c
@@ -503,10 +503,11 @@ STORE(bch2_fs)
 		if (threads_str &&
 		    !(ret = kstrtouint(threads_str, 10, &threads)) &&
 		    !(ret = bch2_strtoull_h(nr_str, &nr)))
-			bch2_btree_perf_test(c, test, nr, threads);
-		else
-			size = ret;
+			ret = bch2_btree_perf_test(c, test, nr, threads);
 		kfree(tmp);
+
+		if (ret)
+			size = ret;
 	}
 #endif
 	return size;
diff --git a/libbcachefs/tests.c b/libbcachefs/tests.c
index 4dcace65..5f40b048 100644
--- a/libbcachefs/tests.c
+++ b/libbcachefs/tests.c
@@ -26,7 +26,7 @@ static void delete_test_keys(struct bch_fs *c)
 
 /* unit tests */
 
-static void test_delete(struct bch_fs *c, u64 nr)
+static int test_delete(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
@@ -41,24 +41,37 @@ static void test_delete(struct bch_fs *c, u64 nr)
 				   BTREE_ITER_INTENT);
 
 	ret = bch2_btree_iter_traverse(iter);
-	BUG_ON(ret);
+	if (ret) {
+		bch_err(c, "lookup error in test_delete: %i", ret);
+		goto err;
+	}
 
 	ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 		bch2_trans_update(&trans, iter, &k.k_i, 0));
-	BUG_ON(ret);
+	if (ret) {
+		bch_err(c, "update error in test_delete: %i", ret);
+		goto err;
+	}
 
 	pr_info("deleting once");
 	ret = bch2_btree_delete_at(&trans, iter, 0);
-	BUG_ON(ret);
+	if (ret) {
+		bch_err(c, "delete error (first) in test_delete: %i", ret);
+		goto err;
+	}
 
 	pr_info("deleting twice");
 	ret = bch2_btree_delete_at(&trans, iter, 0);
-	BUG_ON(ret);
-
+	if (ret) {
+		bch_err(c, "delete error (second) in test_delete: %i", ret);
+		goto err;
+	}
+err:
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void test_delete_written(struct bch_fs *c, u64 nr)
+static int test_delete_written(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
@@ -73,27 +86,37 @@ static void test_delete_written(struct bch_fs *c, u64 nr)
 				   BTREE_ITER_INTENT);
 
 	ret = bch2_btree_iter_traverse(iter);
-	BUG_ON(ret);
+	if (ret) {
+		bch_err(c, "lookup error in test_delete_written: %i", ret);
+		goto err;
+	}
 
 	ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 		bch2_trans_update(&trans, iter, &k.k_i, 0));
-	BUG_ON(ret);
+	if (ret) {
+		bch_err(c, "update error in test_delete_written: %i", ret);
+		goto err;
+	}
 
 	bch2_journal_flush_all_pins(&c->journal);
 
 	ret = bch2_btree_delete_at(&trans, iter, 0);
-	BUG_ON(ret);
-
+	if (ret) {
+		bch_err(c, "delete error in test_delete_written: %i", ret);
+		goto err;
+	}
+err:
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void test_iterate(struct bch_fs *c, u64 nr)
+static int test_iterate(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	u64 i;
-	int ret;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
@@ -109,7 +132,10 @@ static void test_iterate(struct bch_fs *c, u64 nr)
 
 		ret = bch2_btree_insert(c, BTREE_ID_XATTRS, &k.k_i,
 					NULL, NULL, 0);
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "insert error in test_iterate: %i", ret);
+			goto err;
+		}
 	}
 
 	pr_info("iterating forwards");
@@ -132,17 +158,18 @@ static void test_iterate(struct bch_fs *c, u64 nr)
 		BUG_ON(k.k->p.offset != --i);
 
 	BUG_ON(i);
-
+err:
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void test_iterate_extents(struct bch_fs *c, u64 nr)
+static int test_iterate_extents(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	u64 i;
-	int ret;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
@@ -159,7 +186,10 @@ static void test_iterate_extents(struct bch_fs *c, u64 nr)
 
 		ret = bch2_btree_insert(c, BTREE_ID_EXTENTS, &k.k_i,
 					NULL, NULL, 0);
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "insert error in test_iterate_extents: %i", ret);
+			goto err;
+		}
 	}
 
 	pr_info("iterating forwards");
@@ -182,17 +212,18 @@ static void test_iterate_extents(struct bch_fs *c, u64 nr)
 	}
 
 	BUG_ON(i);
-
+err:
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void test_iterate_slots(struct bch_fs *c, u64 nr)
+static int test_iterate_slots(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	u64 i;
-	int ret;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
@@ -208,7 +239,10 @@ static void test_iterate_slots(struct bch_fs *c, u64 nr)
 
 		ret = bch2_btree_insert(c, BTREE_ID_XATTRS, &k.k_i,
 					NULL, NULL, 0);
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "insert error in test_iterate_slots: %i", ret);
+			goto err;
+		}
 	}
 
 	pr_info("iterating forwards");
@@ -240,17 +274,18 @@ static void test_iterate_slots(struct bch_fs *c, u64 nr)
 		if (i == nr * 2)
 			break;
 	}
-
+err:
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void test_iterate_slots_extents(struct bch_fs *c, u64 nr)
+static int test_iterate_slots_extents(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	u64 i;
-	int ret;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
@@ -267,7 +302,10 @@ static void test_iterate_slots_extents(struct bch_fs *c, u64 nr)
 
 		ret = bch2_btree_insert(c, BTREE_ID_EXTENTS, &k.k_i,
 					NULL, NULL, 0);
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "insert error in test_iterate_slots_extents: %i", ret);
+			goto err;
+		}
 	}
 
 	pr_info("iterating forwards");
@@ -299,15 +337,16 @@ static void test_iterate_slots_extents(struct bch_fs *c, u64 nr)
 		if (i == nr)
 			break;
 	}
-
+err:
 	bch2_trans_exit(&trans);
+	return 0;
 }
 
 /*
  * XXX: we really want to make sure we've got a btree with depth > 0 for these
  * tests
  */
-static void test_peek_end(struct bch_fs *c, u64 nr)
+static int test_peek_end(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
@@ -324,9 +363,10 @@ static void test_peek_end(struct bch_fs *c, u64 nr)
 	BUG_ON(k.k);
 
 	bch2_trans_exit(&trans);
+	return 0;
 }
 
-static void test_peek_end_extents(struct bch_fs *c, u64 nr)
+static int test_peek_end_extents(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
@@ -343,14 +383,15 @@ static void test_peek_end_extents(struct bch_fs *c, u64 nr)
 	BUG_ON(k.k);
 
 	bch2_trans_exit(&trans);
+	return 0;
 }
 
 /* extent unit tests */
 
 u64 test_version;
 
-static void insert_test_extent(struct bch_fs *c,
-			       u64 start, u64 end)
+static int insert_test_extent(struct bch_fs *c,
+			      u64 start, u64 end)
 {
 	struct bkey_i_cookie k;
 	int ret;
@@ -364,42 +405,47 @@ static void insert_test_extent(struct bch_fs *c,
 
 	ret = bch2_btree_insert(c, BTREE_ID_EXTENTS, &k.k_i,
 				NULL, NULL, 0);
-	BUG_ON(ret);
+	if (ret)
+		bch_err(c, "insert error in insert_test_extent: %i", ret);
+	return ret;
 }
 
-static void __test_extent_overwrite(struct bch_fs *c,
+static int __test_extent_overwrite(struct bch_fs *c,
 				    u64 e1_start, u64 e1_end,
 				    u64 e2_start, u64 e2_end)
 {
-	insert_test_extent(c, e1_start, e1_end);
-	insert_test_extent(c, e2_start, e2_end);
+	int ret;
+
+	ret   = insert_test_extent(c, e1_start, e1_end) ?:
+		insert_test_extent(c, e2_start, e2_end);
 
 	delete_test_keys(c);
+	return ret;
 }
 
-static void test_extent_overwrite_front(struct bch_fs *c, u64 nr)
+static int test_extent_overwrite_front(struct bch_fs *c, u64 nr)
 {
-	__test_extent_overwrite(c, 0, 64, 0, 32);
-	__test_extent_overwrite(c, 8, 64, 0, 32);
+	return  __test_extent_overwrite(c, 0, 64, 0, 32) ?:
+		__test_extent_overwrite(c, 8, 64, 0, 32);
 }
 
-static void test_extent_overwrite_back(struct bch_fs *c, u64 nr)
+static int test_extent_overwrite_back(struct bch_fs *c, u64 nr)
 {
-	__test_extent_overwrite(c, 0, 64, 32, 64);
-	__test_extent_overwrite(c, 0, 64, 32, 72);
+	return  __test_extent_overwrite(c, 0, 64, 32, 64) ?:
+		__test_extent_overwrite(c, 0, 64, 32, 72);
 }
 
-static void test_extent_overwrite_middle(struct bch_fs *c, u64 nr)
+static int test_extent_overwrite_middle(struct bch_fs *c, u64 nr)
 {
-	__test_extent_overwrite(c, 0, 64, 32, 40);
+	return __test_extent_overwrite(c, 0, 64, 32, 40);
 }
 
-static void test_extent_overwrite_all(struct bch_fs *c, u64 nr)
+static int test_extent_overwrite_all(struct bch_fs *c, u64 nr)
 {
-	__test_extent_overwrite(c, 32, 64,  0,  64);
-	__test_extent_overwrite(c, 32, 64,  0, 128);
-	__test_extent_overwrite(c, 32, 64, 32,  64);
-	__test_extent_overwrite(c, 32, 64, 32, 128);
+	return  __test_extent_overwrite(c, 32, 64,  0,  64) ?:
+		__test_extent_overwrite(c, 32, 64,  0, 128) ?:
+		__test_extent_overwrite(c, 32, 64, 32,  64) ?:
+		__test_extent_overwrite(c, 32, 64, 32, 128);
 }
 
 /* perf tests */
@@ -415,11 +461,11 @@ static u64 test_rand(void)
 	return v;
 }
 
-static void rand_insert(struct bch_fs *c, u64 nr)
+static int rand_insert(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct bkey_i_cookie k;
-	int ret;
+	int ret = 0;
 	u64 i;
 
 	bch2_trans_init(&trans, c, 0, 0);
@@ -430,48 +476,63 @@ static void rand_insert(struct bch_fs *c, u64 nr)
 
 		ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 			__bch2_btree_insert(&trans, BTREE_ID_XATTRS, &k.k_i));
-
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "error in rand_insert: %i", ret);
+			break;
+		}
 	}
 
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void rand_lookup(struct bch_fs *c, u64 nr)
+static int rand_lookup(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
+	int ret = 0;
 	u64 i;
 
 	bch2_trans_init(&trans, c, 0, 0);
+	iter = bch2_trans_get_iter(&trans, BTREE_ID_XATTRS, POS_MIN, 0);
 
 	for (i = 0; i < nr; i++) {
-		iter = bch2_trans_get_iter(&trans, BTREE_ID_XATTRS,
-					   POS(0, test_rand()), 0);
+		bch2_btree_iter_set_pos(iter, POS(0, test_rand()));
 
 		k = bch2_btree_iter_peek(iter);
-		bch2_trans_iter_free(&trans, iter);
+		ret = bkey_err(k);
+		if (ret) {
+			bch_err(c, "error in rand_lookup: %i", ret);
+			break;
+		}
 	}
 
+	bch2_trans_iter_free(&trans, iter);
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void rand_mixed(struct bch_fs *c, u64 nr)
+static int rand_mixed(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
-	int ret;
+	int ret = 0;
 	u64 i;
 
 	bch2_trans_init(&trans, c, 0, 0);
+	iter = bch2_trans_get_iter(&trans, BTREE_ID_XATTRS, POS_MIN, 0);
 
 	for (i = 0; i < nr; i++) {
-		iter = bch2_trans_get_iter(&trans, BTREE_ID_XATTRS,
-					   POS(0, test_rand()), 0);
+		bch2_btree_iter_set_pos(iter, POS(0, test_rand()));
 
 		k = bch2_btree_iter_peek(iter);
+		ret = bkey_err(k);
+		if (ret) {
+			bch_err(c, "lookup error in rand_mixed: %i", ret);
+			break;
+		}
 
 		if (!(i & 3) && k.k) {
 			struct bkey_i_cookie k;
@@ -481,14 +542,16 @@ static void rand_mixed(struct bch_fs *c, u64 nr)
 
 			ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 				bch2_trans_update(&trans, iter, &k.k_i, 0));
-
-			BUG_ON(ret);
+			if (ret) {
+				bch_err(c, "update error in rand_mixed: %i", ret);
+				break;
+			}
 		}
-
-		bch2_trans_iter_free(&trans, iter);
 	}
 
+	bch2_trans_iter_free(&trans, iter);
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
 static int __do_delete(struct btree_trans *trans, struct bpos pos)
@@ -518,10 +581,10 @@ err:
 	return ret;
 }
 
-static void rand_delete(struct bch_fs *c, u64 nr)
+static int rand_delete(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
-	int ret;
+	int ret = 0;
 	u64 i;
 
 	bch2_trans_init(&trans, c, 0, 0);
@@ -531,19 +594,23 @@ static void rand_delete(struct bch_fs *c, u64 nr)
 
 		ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 			__do_delete(&trans, pos));
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "error in rand_delete: %i", ret);
+			break;
+		}
 	}
 
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void seq_insert(struct bch_fs *c, u64 nr)
+static int seq_insert(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	struct bkey_i_cookie insert;
-	int ret;
+	int ret = 0;
 	u64 i = 0;
 
 	bkey_cookie_init(&insert.k_i);
@@ -556,35 +623,39 @@ static void seq_insert(struct bch_fs *c, u64 nr)
 
 		ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 			bch2_trans_update(&trans, iter, &insert.k_i, 0));
-
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "error in seq_insert: %i", ret);
+			break;
+		}
 
 		if (++i == nr)
 			break;
 	}
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void seq_lookup(struct bch_fs *c, u64 nr)
+static int seq_lookup(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
-	int ret;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_XATTRS, POS_MIN, 0, k, ret)
 		;
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void seq_overwrite(struct bch_fs *c, u64 nr)
+static int seq_overwrite(struct bch_fs *c, u64 nr)
 {
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
-	int ret;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
@@ -596,23 +667,28 @@ static void seq_overwrite(struct bch_fs *c, u64 nr)
 
 		ret = __bch2_trans_do(&trans, NULL, NULL, 0,
 			bch2_trans_update(&trans, iter, &u.k_i, 0));
-
-		BUG_ON(ret);
+		if (ret) {
+			bch_err(c, "error in seq_overwrite: %i", ret);
+			break;
+		}
 	}
 	bch2_trans_exit(&trans);
+	return ret;
 }
 
-static void seq_delete(struct bch_fs *c, u64 nr)
+static int seq_delete(struct bch_fs *c, u64 nr)
 {
 	int ret;
 
 	ret = bch2_btree_delete_range(c, BTREE_ID_XATTRS,
 				      POS(0, 0), POS(0, U64_MAX),
 				      NULL);
-	BUG_ON(ret);
+	if (ret)
+		bch_err(c, "error in seq_delete: %i", ret);
+	return ret;
 }
 
-typedef void (*perf_test_fn)(struct bch_fs *, u64);
+typedef int (*perf_test_fn)(struct bch_fs *, u64);
 
 struct test_job {
 	struct bch_fs			*c;
@@ -628,11 +704,13 @@ struct test_job {
 
 	u64				start;
 	u64				finish;
+	int				ret;
 };
 
 static int btree_perf_test_thread(void *data)
 {
 	struct test_job *j = data;
+	int ret;
 
 	if (atomic_dec_and_test(&j->ready)) {
 		wake_up(&j->ready_wait);
@@ -641,7 +719,9 @@ static int btree_perf_test_thread(void *data)
 		wait_event(j->ready_wait, !atomic_read(&j->ready));
 	}
 
-	j->fn(j->c, j->nr / j->nr_threads);
+	ret = j->fn(j->c, j->nr / j->nr_threads);
+	if (ret)
+		j->ret = ret;
 
 	if (atomic_dec_and_test(&j->done)) {
 		j->finish = sched_clock();
@@ -651,8 +731,8 @@ static int btree_perf_test_thread(void *data)
 	return 0;
 }
 
-void bch2_btree_perf_test(struct bch_fs *c, const char *testname,
-			  u64 nr, unsigned nr_threads)
+int bch2_btree_perf_test(struct bch_fs *c, const char *testname,
+			 u64 nr, unsigned nr_threads)
 {
 	struct test_job j = { .c = c, .nr = nr, .nr_threads = nr_threads };
 	char name_buf[20], nr_buf[20], per_sec_buf[20];
@@ -695,7 +775,7 @@ void bch2_btree_perf_test(struct bch_fs *c, const char *testname,
 
 	if (!j.fn) {
 		pr_err("unknown test %s", testname);
-		return;
+		return -EINVAL;
 	}
 
 	//pr_info("running test %s:", testname);
@@ -720,6 +800,7 @@ void bch2_btree_perf_test(struct bch_fs *c, const char *testname,
 		time / NSEC_PER_SEC,
 		time * nr_threads / nr,
 		per_sec_buf);
+	return j.ret;
 }
 
 #endif /* CONFIG_BCACHEFS_TESTS */
diff --git a/libbcachefs/tests.h b/libbcachefs/tests.h
index 551d0764..c73b18ae 100644
--- a/libbcachefs/tests.h
+++ b/libbcachefs/tests.h
@@ -6,7 +6,7 @@ struct bch_fs;
 
 #ifdef CONFIG_BCACHEFS_TESTS
 
-void bch2_btree_perf_test(struct bch_fs *, const char *, u64, unsigned);
+int bch2_btree_perf_test(struct bch_fs *, const char *, u64, unsigned);
 
 #else