diff --git a/.bcachefs_revision b/.bcachefs_revision
index 06ebd7da..46d09322 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-400c2f8d960ac55105bd22905a6ea1a40daa7f4f
+787de128a5caf209845e5a8d0f14f24e1a42492c
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f60972c7..35082ae3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -105,6 +105,7 @@ struct super_block {
 #define DT_LNK		10
 #define DT_SOCK		12
 #define DT_WHT		14
+#define DT_MAX		16
 #endif
 
 /*
diff --git a/libbcachefs/alloc_background.c b/libbcachefs/alloc_background.c
index 2324b81c..fff85c17 100644
--- a/libbcachefs/alloc_background.c
+++ b/libbcachefs/alloc_background.c
@@ -130,7 +130,7 @@ static int bch2_alloc_unpack_v2(struct bkey_alloc_unpacked *out,
 
 #define x(_name, _bits)							\
 	if (fieldnr < a.v->nr_fields) {					\
-		ret = bch2_varint_decode(in, end, &v);			\
+		ret = bch2_varint_decode_fast(in, end, &v);		\
 		if (ret < 0)						\
 			return ret;					\
 		in += ret;						\
@@ -166,7 +166,7 @@ static void bch2_alloc_pack_v2(struct bkey_alloc_buf *dst,
 	nr_fields++;							\
 									\
 	if (src._name) {						\
-		out += bch2_varint_encode(out, src._name);		\
+		out += bch2_varint_encode_fast(out, src._name);		\
 									\
 		last_nonzero_field = out;				\
 		last_nonzero_fieldnr = nr_fields;			\
@@ -1232,3 +1232,22 @@ void bch2_fs_allocator_background_init(struct bch_fs *c)
 {
 	spin_lock_init(&c->freelist_lock);
 }
+
+void bch2_open_buckets_to_text(struct printbuf *out, struct bch_fs *c)
+{
+	struct open_bucket *ob;
+
+	for (ob = c->open_buckets;
+	     ob < c->open_buckets + ARRAY_SIZE(c->open_buckets);
+	     ob++) {
+		spin_lock(&ob->lock);
+		if (ob->valid && !ob->on_partial_list) {
+			pr_buf(out, "%zu ref %u type %s\n",
+			       ob - c->open_buckets,
+			       atomic_read(&ob->pin),
+			       bch2_data_types[ob->type]);
+		}
+		spin_unlock(&ob->lock);
+	}
+
+}
diff --git a/libbcachefs/alloc_background.h b/libbcachefs/alloc_background.h
index 9cadfdb5..a4f6bf56 100644
--- a/libbcachefs/alloc_background.h
+++ b/libbcachefs/alloc_background.h
@@ -132,4 +132,6 @@ int bch2_dev_allocator_start(struct bch_dev *);
 int bch2_alloc_write(struct bch_fs *, unsigned);
 void bch2_fs_allocator_background_init(struct bch_fs *);
 
+void bch2_open_buckets_to_text(struct printbuf *, struct bch_fs *);
+
 #endif /* _BCACHEFS_ALLOC_BACKGROUND_H */
diff --git a/libbcachefs/bcachefs_format.h b/libbcachefs/bcachefs_format.h
index 94273d51..8a89ab0d 100644
--- a/libbcachefs/bcachefs_format.h
+++ b/libbcachefs/bcachefs_format.h
@@ -1346,6 +1346,7 @@ LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,	struct bch_sb, flags[2],  4, 64);
 LE64_BITMASK(BCH_SB_ERASURE_CODE,	struct bch_sb, flags[3],  0, 16);
 LE64_BITMASK(BCH_SB_METADATA_TARGET,	struct bch_sb, flags[3], 16, 28);
 LE64_BITMASK(BCH_SB_SHARD_INUMS,	struct bch_sb, flags[3], 28, 29);
+LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
 
 /*
  * Features:
diff --git a/libbcachefs/btree_cache.c b/libbcachefs/btree_cache.c
index 73bfd01f..1aacd271 100644
--- a/libbcachefs/btree_cache.c
+++ b/libbcachefs/btree_cache.c
@@ -233,7 +233,7 @@ wait_on_io:
 		if (bch2_verify_btree_ondisk)
 			bch2_btree_node_write(c, b, SIX_LOCK_intent);
 		else
-			__bch2_btree_node_write(c, b);
+			__bch2_btree_node_write(c, b, false);
 
 		six_unlock_write(&b->c.lock);
 		six_unlock_intent(&b->c.lock);
@@ -691,7 +691,9 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	 * currently fails for iterators that aren't pointed at a valid btree
 	 * node
 	 */
-	if (iter && !bch2_trans_relock(iter->trans))
+	if (iter &&
+	    (!bch2_trans_relock(iter->trans) ||
+	     !bch2_btree_iter_relock(iter, _THIS_IP_)))
 		return ERR_PTR(-EINTR);
 
 	if (!six_relock_type(&b->c.lock, lock_type, seq))
@@ -851,7 +853,9 @@ lock_node:
 		 * currently fails for iterators that aren't pointed at a valid
 		 * btree node
 		 */
-		if (iter && !bch2_trans_relock(iter->trans))
+		if (iter &&
+		    (!bch2_trans_relock(iter->trans) ||
+		     !bch2_btree_iter_relock(iter, _THIS_IP_)))
 			return ERR_PTR(-EINTR);
 
 		if (!six_relock_type(&b->c.lock, lock_type, seq))
@@ -1002,7 +1006,7 @@ wait_on_io:
 	six_lock_write(&b->c.lock, NULL, NULL);
 
 	if (btree_node_dirty(b)) {
-		__bch2_btree_node_write(c, b);
+		__bch2_btree_node_write(c, b, false);
 		six_unlock_write(&b->c.lock);
 		six_unlock_intent(&b->c.lock);
 		goto wait_on_io;
diff --git a/libbcachefs/btree_io.c b/libbcachefs/btree_io.c
index 12894f89..957a6a9a 100644
--- a/libbcachefs/btree_io.c
+++ b/libbcachefs/btree_io.c
@@ -1566,9 +1566,47 @@ void bch2_btree_complete_write(struct bch_fs *c, struct btree *b,
 static void btree_node_write_done(struct bch_fs *c, struct btree *b)
 {
 	struct btree_write *w = btree_prev_write(b);
+	unsigned long old, new, v;
 
 	bch2_btree_complete_write(c, b, w);
-	bch2_btree_node_io_unlock(b);
+
+	v = READ_ONCE(b->flags);
+	do {
+		old = new = v;
+
+		if (old & (1U << BTREE_NODE_need_write))
+			goto do_write;
+
+		new &= ~(1U << BTREE_NODE_write_in_flight);
+	} while ((v = cmpxchg(&b->flags, old, new)) != old);
+
+	wake_up_bit(&b->flags, BTREE_NODE_write_in_flight);
+	return;
+
+do_write:
+	six_lock_read(&b->c.lock, NULL, NULL);
+	v = READ_ONCE(b->flags);
+	do {
+		old = new = v;
+
+		if ((old & (1U << BTREE_NODE_dirty)) &&
+		    (old & (1U << BTREE_NODE_need_write)) &&
+		    !(old & (1U << BTREE_NODE_never_write)) &&
+		    btree_node_may_write(b)) {
+			new &= ~(1U << BTREE_NODE_dirty);
+			new &= ~(1U << BTREE_NODE_need_write);
+			new |=  (1U << BTREE_NODE_write_in_flight);
+			new |=  (1U << BTREE_NODE_just_written);
+			new ^=  (1U << BTREE_NODE_write_idx);
+		} else {
+			new &= ~(1U << BTREE_NODE_write_in_flight);
+		}
+	} while ((v = cmpxchg(&b->flags, old, new)) != old);
+
+	if (new & (1U << BTREE_NODE_write_in_flight))
+		__bch2_btree_node_write(c, b, true);
+
+	six_unlock_read(&b->c.lock);
 }
 
 static void bch2_btree_node_write_error(struct bch_fs *c,
@@ -1733,7 +1771,7 @@ static void btree_write_submit(struct work_struct *work)
 	bch2_submit_wbio_replicas(&wbio->wbio, wbio->wbio.c, BCH_DATA_btree, &wbio->key);
 }
 
-void __bch2_btree_node_write(struct bch_fs *c, struct btree *b)
+void __bch2_btree_node_write(struct bch_fs *c, struct btree *b, bool already_started)
 {
 	struct btree_write_bio *wbio;
 	struct bset_tree *t;
@@ -1750,7 +1788,8 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b)
 	bool validate_before_checksum = false;
 	void *data;
 
-	BUG_ON(btree_node_write_in_flight(b));
+	if (already_started)
+		goto do_write;
 
 	if (test_bit(BCH_FS_HOLD_BTREE_WRITES, &c->flags))
 		return;
@@ -1774,14 +1813,7 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b)
 		if (old & (1 << BTREE_NODE_never_write))
 			return;
 
-		if (old & (1 << BTREE_NODE_write_in_flight)) {
-			/*
-			 * XXX waiting on btree writes with btree locks held -
-			 * this can deadlock, and we hit the write error path
-			 */
-			bch2_btree_node_wait_on_write(b);
-			continue;
-		}
+		BUG_ON(old & (1 << BTREE_NODE_write_in_flight));
 
 		new &= ~(1 << BTREE_NODE_dirty);
 		new &= ~(1 << BTREE_NODE_need_write);
@@ -1790,6 +1822,9 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b)
 		new ^=  (1 << BTREE_NODE_write_idx);
 	} while (cmpxchg_acquire(&b->flags, old, new) != old);
 
+	if (new & (1U << BTREE_NODE_need_write))
+		return;
+do_write:
 	atomic_dec(&c->btree_cache.dirty);
 
 	BUG_ON(btree_node_fake(b));
@@ -2044,7 +2079,7 @@ void bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 	if (lock_type_held == SIX_LOCK_intent ||
 	    (lock_type_held == SIX_LOCK_read &&
 	     six_lock_tryupgrade(&b->c.lock))) {
-		__bch2_btree_node_write(c, b);
+		__bch2_btree_node_write(c, b, false);
 
 		/* don't cycle lock unnecessarily: */
 		if (btree_node_just_written(b) &&
@@ -2056,7 +2091,7 @@ void bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 		if (lock_type_held == SIX_LOCK_read)
 			six_lock_downgrade(&b->c.lock);
 	} else {
-		__bch2_btree_node_write(c, b);
+		__bch2_btree_node_write(c, b, false);
 		if (lock_type_held == SIX_LOCK_write &&
 		    btree_node_just_written(b))
 			bch2_btree_post_write_cleanup(c, b);
diff --git a/libbcachefs/btree_io.h b/libbcachefs/btree_io.h
index 89fd4aba..3732d135 100644
--- a/libbcachefs/btree_io.h
+++ b/libbcachefs/btree_io.h
@@ -139,7 +139,7 @@ void bch2_btree_complete_write(struct bch_fs *, struct btree *,
 			      struct btree_write *);
 void bch2_btree_write_error_work(struct work_struct *);
 
-void __bch2_btree_node_write(struct bch_fs *, struct btree *);
+void __bch2_btree_node_write(struct bch_fs *, struct btree *, bool);
 bool bch2_btree_post_write_cleanup(struct bch_fs *, struct btree *);
 
 void bch2_btree_node_write(struct bch_fs *, struct btree *,
@@ -148,18 +148,11 @@ void bch2_btree_node_write(struct bch_fs *, struct btree *,
 static inline void btree_node_write_if_need(struct bch_fs *c, struct btree *b,
 					    enum six_lock_type lock_held)
 {
-	while (b->written &&
-	       btree_node_need_write(b) &&
-	       btree_node_may_write(b)) {
-		if (!btree_node_write_in_flight(b)) {
-			bch2_btree_node_write(c, b, lock_held);
-			break;
-		}
-
-		six_unlock_type(&b->c.lock, lock_held);
-		bch2_btree_node_wait_on_write(b);
-		btree_node_lock_type(c, b, lock_held);
-	}
+	if (b->written &&
+	    btree_node_need_write(b) &&
+	    btree_node_may_write(b) &&
+	    !btree_node_write_in_flight(b))
+		bch2_btree_node_write(c, b, lock_held);
 }
 
 #define bch2_btree_node_write_cond(_c, _b, cond)			\
diff --git a/libbcachefs/btree_iter.c b/libbcachefs/btree_iter.c
index 0444dbd1..24d7422c 100644
--- a/libbcachefs/btree_iter.c
+++ b/libbcachefs/btree_iter.c
@@ -347,6 +347,7 @@ bool __bch2_btree_node_lock(struct btree *b, struct bpos pos,
 #ifdef CONFIG_BCACHEFS_DEBUG
 static void bch2_btree_iter_verify_locks(struct btree_iter *iter)
 {
+	struct bch_fs *c = iter->trans->c;
 	unsigned l;
 
 	if (!(iter->trans->iters_linked & (1ULL << iter->idx))) {
@@ -354,7 +355,7 @@ static void bch2_btree_iter_verify_locks(struct btree_iter *iter)
 		return;
 	}
 
-	for (l = 0; is_btree_node(iter, l); l++) {
+	for (l = 0; btree_iter_node(iter, l); l++) {
 		if (iter->uptodate >= BTREE_ITER_NEED_RELOCK &&
 		    !btree_node_locked(iter, l))
 			continue;
@@ -376,7 +377,7 @@ static inline void bch2_btree_iter_verify_locks(struct btree_iter *iter) {}
 #endif
 
 __flatten
-static bool bch2_btree_iter_relock(struct btree_iter *iter, unsigned long trace_ip)
+bool bch2_btree_iter_relock(struct btree_iter *iter, unsigned long trace_ip)
 {
 	return btree_iter_get_locks(iter, false, trace_ip);
 }
@@ -602,6 +603,8 @@ err:
 
 static void bch2_btree_iter_verify(struct btree_iter *iter)
 {
+	struct btree_trans *trans = iter->trans;
+	struct bch_fs *c = trans->c;
 	enum btree_iter_type type = btree_iter_type(iter);
 	unsigned i;
 
@@ -620,10 +623,16 @@ static void bch2_btree_iter_verify(struct btree_iter *iter)
 	       (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
 	       !btree_type_has_snapshots(iter->btree_id));
 
-	bch2_btree_iter_verify_locks(iter);
+	for (i = 0; i < BTREE_MAX_DEPTH; i++) {
+		if (!iter->l[i].b) {
+			BUG_ON(c->btree_roots[iter->btree_id].b->c.level > i);
+			break;
+		}
 
-	for (i = 0; i < BTREE_MAX_DEPTH; i++)
 		bch2_btree_iter_verify_level(iter, i);
+	}
+
+	bch2_btree_iter_verify_locks(iter);
 }
 
 static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)
@@ -1345,30 +1354,30 @@ static inline unsigned btree_iter_up_until_good_node(struct btree_iter *iter,
 static int btree_iter_traverse_one(struct btree_iter *iter,
 				   unsigned long trace_ip)
 {
-	unsigned depth_want = iter->level;
+	unsigned l, depth_want = iter->level;
 	int ret = 0;
 
-	/*
-	 * if we need interior nodes locked, call btree_iter_relock() to make
-	 * sure we walk back up enough that we lock them:
-	 */
-	if (iter->uptodate == BTREE_ITER_NEED_RELOCK ||
-	    iter->locks_want > 1)
-		bch2_btree_iter_relock(iter, _THIS_IP_);
-
 	if (btree_iter_type(iter) == BTREE_ITER_CACHED) {
 		ret = bch2_btree_iter_traverse_cached(iter);
 		goto out;
 	}
 
-	if (iter->uptodate < BTREE_ITER_NEED_RELOCK)
-		goto out;
-
 	if (unlikely(iter->level >= BTREE_MAX_DEPTH))
 		goto out;
 
 	iter->level = btree_iter_up_until_good_node(iter, 0);
 
+	/* If we need intent locks, take them too: */
+	for (l = iter->level + 1;
+	     l < iter->locks_want && btree_iter_node(iter, l);
+	     l++)
+		if (!bch2_btree_node_relock(iter, l))
+			while (iter->level <= l) {
+				btree_node_unlock(iter, iter->level);
+				iter->l[iter->level].b = BTREE_ITER_NO_NODE_UP;
+				iter->level++;
+			}
+
 	/*
 	 * Note: iter->nodes[iter->level] may be temporarily NULL here - that
 	 * would indicate to other code that we got to the end of the btree,
@@ -1389,6 +1398,7 @@ static int btree_iter_traverse_one(struct btree_iter *iter,
 				goto out;
 			}
 
+			__bch2_btree_iter_unlock(iter);
 			iter->level = depth_want;
 
 			if (ret == -EIO) {
diff --git a/libbcachefs/btree_iter.h b/libbcachefs/btree_iter.h
index 31175cf0..58f15b71 100644
--- a/libbcachefs/btree_iter.h
+++ b/libbcachefs/btree_iter.h
@@ -111,6 +111,8 @@ void bch2_btree_node_iter_fix(struct btree_iter *, struct btree *,
 			      struct btree_node_iter *, struct bkey_packed *,
 			      unsigned, unsigned);
 
+bool bch2_btree_iter_relock(struct btree_iter *, unsigned long);
+
 bool bch2_trans_relock(struct btree_trans *);
 void bch2_trans_unlock(struct btree_trans *);
 
diff --git a/libbcachefs/btree_key_cache.c b/libbcachefs/btree_key_cache.c
index dfaf5e6d..7f47ef33 100644
--- a/libbcachefs/btree_key_cache.c
+++ b/libbcachefs/btree_key_cache.c
@@ -270,7 +270,9 @@ int bch2_btree_iter_traverse_cached(struct btree_iter *iter)
 
 	BUG_ON(iter->level);
 
-	if (btree_node_locked(iter, 0)) {
+	iter->l[1].b = NULL;
+
+	if (bch2_btree_node_relock(iter, 0)) {
 		ck = (void *) iter->l[0].b;
 		goto fill;
 	}
diff --git a/libbcachefs/btree_update_interior.c b/libbcachefs/btree_update_interior.c
index 6b55a410..0b4e4056 100644
--- a/libbcachefs/btree_update_interior.c
+++ b/libbcachefs/btree_update_interior.c
@@ -948,13 +948,6 @@ bch2_btree_update_start(struct btree_iter *iter, unsigned level,
 
 	closure_init_stack(&cl);
 retry:
-	/*
-	 * This check isn't necessary for correctness - it's just to potentially
-	 * prevent us from doing a lot of work that'll end up being wasted:
-	 */
-	ret = bch2_journal_error(&c->journal);
-	if (ret)
-		return ERR_PTR(ret);
 
 	/*
 	 * XXX: figure out how far we might need to split,
@@ -995,6 +988,22 @@ retry:
 	bch2_keylist_init(&as->new_keys, as->_new_keys);
 	bch2_keylist_init(&as->parent_keys, as->inline_keys);
 
+	mutex_lock(&c->btree_interior_update_lock);
+	list_add_tail(&as->list, &c->btree_interior_update_list);
+	mutex_unlock(&c->btree_interior_update_lock);
+
+	/*
+	 * We don't want to allocate if we're in an error state, that can cause
+	 * deadlock on emergency shutdown due to open buckets getting stuck in
+	 * the btree_reserve_cache after allocator shutdown has cleared it out.
+	 * This check needs to come after adding us to the btree_interior_update
+	 * list but before calling bch2_btree_reserve_get, to synchronize with
+	 * __bch2_fs_read_only().
+	 */
+	ret = bch2_journal_error(&c->journal);
+	if (ret)
+		goto err;
+
 	ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
 				      BTREE_UPDATE_JOURNAL_RES,
 				      journal_flags|JOURNAL_RES_GET_NONBLOCK);
@@ -1046,10 +1055,6 @@ retry:
 			     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);
-
 	return as;
 err:
 	bch2_btree_update_free(as);
diff --git a/libbcachefs/dirent.c b/libbcachefs/dirent.c
index d5883ab7..a95165b8 100644
--- a/libbcachefs/dirent.c
+++ b/libbcachefs/dirent.c
@@ -112,7 +112,10 @@ void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c,
 
 	bch_scnmemcpy(out, d.v->d_name,
 		      bch2_dirent_name_bytes(d));
-	pr_buf(out, " -> %llu type %s", d.v->d_inum, bch2_d_types[d.v->d_type]);
+	pr_buf(out, " -> %llu type %s", d.v->d_inum,
+	       d.v->d_type < DT_MAX
+	       ? bch2_d_types[d.v->d_type]
+	       : "(bad d_type)");
 }
 
 static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
diff --git a/libbcachefs/fs-io.c b/libbcachefs/fs-io.c
index 2795b37b..ae55453b 100644
--- a/libbcachefs/fs-io.c
+++ b/libbcachefs/fs-io.c
@@ -1870,8 +1870,6 @@ static long bch2_dio_write_loop(struct dio_write *dio)
 			 * bio_iov_iter_get_pages was only able to get <
 			 * blocksize worth of pages:
 			 */
-			bio_for_each_segment_all(bv, bio, iter)
-				put_page(bv->bv_page);
 			ret = -EFAULT;
 			goto err;
 		}
@@ -1939,6 +1937,7 @@ loop:
 		if (likely(!bio_flagged(bio, BIO_NO_PAGE_REF)))
 			bio_for_each_segment_all(bv, bio, iter)
 				put_page(bv->bv_page);
+		bio->bi_vcnt = 0;
 
 		if (dio->op.error) {
 			set_bit(EI_INODE_ERROR, &inode->ei_flags);
@@ -1961,6 +1960,9 @@ err:
 	if (dio->free_iov)
 		kfree(dio->iter.iov);
 
+	if (likely(!bio_flagged(bio, BIO_NO_PAGE_REF)))
+		bio_for_each_segment_all(bv, bio, iter)
+			put_page(bv->bv_page);
 	bio_put(bio);
 
 	/* inode->i_dio_count is our ref on inode and thus bch_fs */
diff --git a/libbcachefs/fsck.c b/libbcachefs/fsck.c
index 7ea1a41a..bedfd348 100644
--- a/libbcachefs/fsck.c
+++ b/libbcachefs/fsck.c
@@ -267,11 +267,11 @@ static struct inode_walker inode_walker_init(void)
 	};
 }
 
-static int walk_inode(struct btree_trans *trans,
-		      struct inode_walker *w, u64 inum)
+static int __walk_inode(struct btree_trans *trans,
+			struct inode_walker *w, u64 inum)
 {
 	if (inum != w->cur_inum) {
-		int ret = lookup_inode(trans, inum, &w->inode, &w->snapshot);
+		int ret = __lookup_inode(trans, inum, &w->inode, &w->snapshot);
 
 		if (ret && ret != -ENOENT)
 			return ret;
@@ -286,6 +286,12 @@ static int walk_inode(struct btree_trans *trans,
 	return 0;
 }
 
+static int walk_inode(struct btree_trans *trans,
+		      struct inode_walker *w, u64 inum)
+{
+	return lockrestart_do(trans, __walk_inode(trans, w, inum));
+}
+
 static int hash_redo_key(struct btree_trans *trans,
 			 const struct bch_hash_desc desc,
 			 struct bch_hash_info *hash_info,
@@ -704,6 +710,177 @@ fsck_err:
 	return bch2_trans_exit(&trans) ?: ret;
 }
 
+static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
+			struct bch_hash_info *hash_info,
+			struct inode_walker *w, unsigned *nr_subdirs)
+{
+	struct bch_fs *c = trans->c;
+	struct bkey_s_c k;
+	struct bkey_s_c_dirent d;
+	struct bch_inode_unpacked target;
+	u32 target_snapshot;
+	bool have_target;
+	bool backpointer_exists = true;
+	u64 d_inum;
+	char buf[200];
+	int ret;
+
+	k = bch2_btree_iter_peek(iter);
+	if (!k.k)
+		return 1;
+
+	ret = bkey_err(k);
+	if (ret)
+		return ret;
+
+	if (w->have_inode &&
+	    w->cur_inum != k.k->p.inode &&
+	    fsck_err_on(w->inode.bi_nlink != *nr_subdirs, c,
+			"directory %llu with wrong i_nlink: got %u, should be %u",
+			w->inode.bi_inum, w->inode.bi_nlink, *nr_subdirs)) {
+		w->inode.bi_nlink = *nr_subdirs;
+		ret = write_inode(trans, &w->inode, w->snapshot);
+		return ret ?: -EINTR;
+	}
+
+	ret = __walk_inode(trans, w, k.k->p.inode);
+	if (ret)
+		return ret;
+
+	if (w->first_this_inode)
+		*nr_subdirs = 0;
+
+	if (fsck_err_on(!w->have_inode, c,
+			"dirent in nonexisting directory:\n%s",
+			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)) ||
+	    fsck_err_on(!S_ISDIR(w->inode.bi_mode), c,
+			"dirent in non directory inode type %u:\n%s",
+			mode_to_type(w->inode.bi_mode),
+			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))
+		return __bch2_trans_do(trans, NULL, NULL, 0,
+				bch2_btree_delete_at(trans, iter, 0));
+
+	if (!w->have_inode)
+		return 0;
+
+	if (w->first_this_inode)
+		*hash_info = bch2_hash_info_init(c, &w->inode);
+
+	ret = hash_check_key(trans, bch2_dirent_hash_desc,
+			     hash_info, iter, k);
+	if (ret < 0)
+		return ret;
+	if (ret) /* dirent has been deleted */
+		return 0;
+
+	if (k.k->type != KEY_TYPE_dirent)
+		return 0;
+
+	d = bkey_s_c_to_dirent(k);
+	d_inum = le64_to_cpu(d.v->d_inum);
+
+	ret = __lookup_inode(trans, d_inum, &target, &target_snapshot);
+	if (ret && ret != -ENOENT)
+		return ret;
+
+	have_target = !ret;
+	ret = 0;
+
+	if (fsck_err_on(!have_target, c,
+			"dirent points to missing inode:\n%s",
+			(bch2_bkey_val_to_text(&PBUF(buf), c,
+					       k), buf)))
+		return remove_dirent(trans, d.k->p);
+
+	if (!have_target)
+		return 0;
+
+	if (!target.bi_dir &&
+	    !target.bi_dir_offset) {
+		target.bi_dir		= k.k->p.inode;
+		target.bi_dir_offset	= k.k->p.offset;
+
+		ret = __write_inode(trans, &target, target_snapshot) ?:
+			bch2_trans_commit(trans, NULL, NULL,
+					  BTREE_INSERT_NOFAIL|
+					  BTREE_INSERT_LAZY_RW|
+					  BTREE_INSERT_NOUNLOCK);
+		if (ret)
+			return ret;
+		return -EINTR;
+	}
+
+	if (!inode_backpointer_matches(d, &target)) {
+		ret = inode_backpointer_exists(trans, &target);
+		if (ret < 0)
+			return ret;
+
+		backpointer_exists = ret;
+		ret = 0;
+
+		if (fsck_err_on(S_ISDIR(target.bi_mode) &&
+				backpointer_exists, c,
+				"directory %llu with multiple links",
+				target.bi_inum))
+			return remove_dirent(trans, d.k->p);
+
+		if (fsck_err_on(backpointer_exists &&
+				!target.bi_nlink, c,
+				"inode %llu has multiple links but i_nlink 0",
+				d_inum)) {
+			target.bi_nlink++;
+			target.bi_flags &= ~BCH_INODE_UNLINKED;
+
+			ret = write_inode(trans, &target, target_snapshot);
+			return ret ?: -EINTR;
+		}
+
+		if (fsck_err_on(!backpointer_exists, c,
+				"inode %llu has wrong backpointer:\n"
+				"got       %llu:%llu\n"
+				"should be %llu:%llu",
+				d_inum,
+				target.bi_dir,
+				target.bi_dir_offset,
+				k.k->p.inode,
+				k.k->p.offset)) {
+			target.bi_dir		= k.k->p.inode;
+			target.bi_dir_offset	= k.k->p.offset;
+
+			ret = write_inode(trans, &target, target_snapshot);
+			return ret ?: -EINTR;
+		}
+	}
+
+	if (fsck_err_on(d.v->d_type != mode_to_type(target.bi_mode), c,
+			"incorrect d_type: should be %u:\n%s",
+			mode_to_type(target.bi_mode),
+			(bch2_bkey_val_to_text(&PBUF(buf), c,
+					       k), buf))) {
+		struct bkey_i_dirent *n;
+
+		n = kmalloc(bkey_bytes(d.k), GFP_KERNEL);
+		if (!n)
+			return -ENOMEM;
+
+		bkey_reassemble(&n->k_i, d.s_c);
+		n->v.d_type = mode_to_type(target.bi_mode);
+
+		ret = __bch2_trans_do(trans, NULL, NULL,
+				      BTREE_INSERT_NOFAIL|
+				      BTREE_INSERT_LAZY_RW,
+			bch2_btree_iter_traverse(iter) ?:
+			bch2_trans_update(trans, iter, &n->k_i, 0));
+		kfree(n);
+		return ret ?: -EINTR;
+	}
+
+	*nr_subdirs += d.v->d_type == DT_DIR;
+	return 0;
+fsck_err:
+	return ret;
+}
+
 /*
  * Walk dirents: verify that they all have a corresponding S_ISDIR inode,
  * validate d_type
@@ -715,8 +892,6 @@ static int check_dirents(struct bch_fs *c)
 	struct bch_hash_info hash_info;
 	struct btree_trans trans;
 	struct btree_iter *iter;
-	struct bkey_s_c k;
-	char buf[200];
 	unsigned nr_subdirs = 0;
 	int ret = 0;
 
@@ -728,186 +903,22 @@ static int check_dirents(struct bch_fs *c)
 				   POS(BCACHEFS_ROOT_INO, 0),
 				   BTREE_ITER_INTENT|
 				   BTREE_ITER_PREFETCH);
-retry:
-	while ((k = bch2_btree_iter_peek(iter)).k &&
-	       !(ret = bkey_err(k))) {
-		struct bkey_s_c_dirent d;
-		struct bch_inode_unpacked target;
-		u32 target_snapshot;
-		bool have_target;
-		bool backpointer_exists = true;
-		u64 d_inum;
 
-		if (w.have_inode &&
-		    w.cur_inum != k.k->p.inode &&
-		    fsck_err_on(w.inode.bi_nlink != nr_subdirs, c,
-				"directory %llu with wrong i_nlink: got %u, should be %u",
-				w.inode.bi_inum, w.inode.bi_nlink, nr_subdirs)) {
-			w.inode.bi_nlink = nr_subdirs;
-			ret = write_inode(&trans, &w.inode, w.snapshot);
-			if (ret)
-				break;
+	while (1) {
+		ret = lockrestart_do(&trans,
+				check_dirent(&trans, iter, &hash_info, &w, &nr_subdirs));
+		if (ret == 1) {
+			/* at end */
+			ret = 0;
+			break;
 		}
-
-		ret = walk_inode(&trans, &w, k.k->p.inode);
 		if (ret)
 			break;
 
-		if (w.first_this_inode)
-			nr_subdirs = 0;
-
-		if (fsck_err_on(!w.have_inode, c,
-				"dirent in nonexisting directory:\n%s",
-				(bch2_bkey_val_to_text(&PBUF(buf), c,
-						       k), buf)) ||
-		    fsck_err_on(!S_ISDIR(w.inode.bi_mode), c,
-				"dirent in non directory inode type %u:\n%s",
-				mode_to_type(w.inode.bi_mode),
-				(bch2_bkey_val_to_text(&PBUF(buf), c,
-						       k), buf))) {
-			ret = __bch2_trans_do(&trans, NULL, NULL, 0,
-					bch2_btree_delete_at(&trans, iter, 0));
-			if (ret)
-				goto err;
-			goto next;
-		}
-
-		if (!w.have_inode)
-			goto next;
-
-		if (w.first_this_inode)
-			hash_info = bch2_hash_info_init(c, &w.inode);
-
-		ret = hash_check_key(&trans, bch2_dirent_hash_desc,
-				     &hash_info, iter, k);
-		if (ret > 0) {
-			ret = 0;
-			goto next;
-		}
-		if (ret)
-			goto fsck_err;
-
-		if (k.k->type != KEY_TYPE_dirent)
-			goto next;
-
-		d = bkey_s_c_to_dirent(k);
-		d_inum = le64_to_cpu(d.v->d_inum);
-
-		ret = lookup_inode(&trans, d_inum, &target, &target_snapshot);
-		if (ret && ret != -ENOENT)
-			break;
-
-		have_target = !ret;
-		ret = 0;
-
-		if (fsck_err_on(!have_target, c,
-				"dirent points to missing inode:\n%s",
-				(bch2_bkey_val_to_text(&PBUF(buf), c,
-						       k), buf))) {
-			ret = remove_dirent(&trans, d.k->p);
-			if (ret)
-				goto err;
-			goto next;
-		}
-
-		if (!have_target)
-			goto next;
-
-		if (!target.bi_dir &&
-		    !target.bi_dir_offset) {
-			target.bi_dir		= k.k->p.inode;
-			target.bi_dir_offset	= k.k->p.offset;
-
-			ret = write_inode(&trans, &target, target_snapshot);
-			if (ret)
-				goto err;
-		}
-
-		if (!inode_backpointer_matches(d, &target)) {
-			ret = inode_backpointer_exists(&trans, &target);
-			if (ret < 0)
-				goto err;
-
-			backpointer_exists = ret;
-			ret = 0;
-
-			if (fsck_err_on(S_ISDIR(target.bi_mode) &&
-					backpointer_exists, c,
-					"directory %llu with multiple links",
-					target.bi_inum)) {
-				ret = remove_dirent(&trans, d.k->p);
-				if (ret)
-					goto err;
-				continue;
-			}
-
-			if (fsck_err_on(backpointer_exists &&
-					!target.bi_nlink, c,
-					"inode %llu has multiple links but i_nlink 0",
-					d_inum)) {
-				target.bi_nlink++;
-				target.bi_flags &= ~BCH_INODE_UNLINKED;
-
-				ret = write_inode(&trans, &target, target_snapshot);
-				if (ret)
-					goto err;
-			}
-
-			if (fsck_err_on(!backpointer_exists, c,
-					"inode %llu has wrong backpointer:\n"
-					"got       %llu:%llu\n"
-					"should be %llu:%llu",
-					d_inum,
-					target.bi_dir,
-					target.bi_dir_offset,
-					k.k->p.inode,
-					k.k->p.offset)) {
-				target.bi_dir		= k.k->p.inode;
-				target.bi_dir_offset	= k.k->p.offset;
-
-				ret = write_inode(&trans, &target, target_snapshot);
-				if (ret)
-					goto err;
-			}
-		}
-
-		if (fsck_err_on(d.v->d_type != mode_to_type(target.bi_mode), c,
-				"incorrect d_type: should be %u:\n%s",
-				mode_to_type(target.bi_mode),
-				(bch2_bkey_val_to_text(&PBUF(buf), c,
-						       k), buf))) {
-			struct bkey_i_dirent *n;
-
-			n = kmalloc(bkey_bytes(d.k), GFP_KERNEL);
-			if (!n) {
-				ret = -ENOMEM;
-				goto err;
-			}
-
-			bkey_reassemble(&n->k_i, d.s_c);
-			n->v.d_type = mode_to_type(target.bi_mode);
-
-			ret = __bch2_trans_do(&trans, NULL, NULL,
-					      BTREE_INSERT_NOFAIL|
-					      BTREE_INSERT_LAZY_RW,
-				bch2_btree_iter_traverse(iter) ?:
-				bch2_trans_update(&trans, iter, &n->k_i, 0));
-			kfree(n);
-			if (ret)
-				goto err;
-
-		}
-
-		nr_subdirs += d.v->d_type == DT_DIR;
-next:
 		bch2_btree_iter_advance(iter);
 	}
-err:
-fsck_err:
-	if (ret == -EINTR)
-		goto retry;
-
 	bch2_trans_iter_put(&trans, iter);
+
 	return bch2_trans_exit(&trans) ?: ret;
 }
 
diff --git a/libbcachefs/inode.c b/libbcachefs/inode.c
index 59edb4ce..67983ff4 100644
--- a/libbcachefs/inode.c
+++ b/libbcachefs/inode.c
@@ -137,7 +137,7 @@ static void bch2_inode_pack_v2(struct bkey_inode_buf *packed,
 	nr_fields++;							\
 									\
 	if (inode->_name) {						\
-		ret = bch2_varint_encode(out, inode->_name);		\
+		ret = bch2_varint_encode_fast(out, inode->_name);	\
 		out += ret;						\
 									\
 		if (_bits > 64)						\
@@ -246,13 +246,13 @@ static int bch2_inode_unpack_v2(struct bkey_s_c_inode inode,
 
 #define x(_name, _bits)							\
 	if (fieldnr < INODE_NR_FIELDS(inode.v)) {			\
-		ret = bch2_varint_decode(in, end, &v[0]);		\
+		ret = bch2_varint_decode_fast(in, end, &v[0]);		\
 		if (ret < 0)						\
 			return ret;					\
 		in += ret;						\
 									\
 		if (_bits > 64) {					\
-			ret = bch2_varint_decode(in, end, &v[1]);	\
+			ret = bch2_varint_decode_fast(in, end, &v[1]);	\
 			if (ret < 0)					\
 				return ret;				\
 			in += ret;					\
@@ -300,8 +300,10 @@ struct btree_iter *bch2_inode_peek(struct btree_trans *trans,
 	struct bkey_s_c k;
 	int ret;
 
-	iter = bch2_trans_get_iter(trans, BTREE_ID_inodes, POS(0, inum),
-				   BTREE_ITER_CACHED|flags);
+	if (trans->c->opts.inodes_use_key_cache)
+		flags |= BTREE_ITER_CACHED;
+
+	iter = bch2_trans_get_iter(trans, BTREE_ID_inodes, POS(0, inum), flags);
 	k = bch2_btree_iter_peek_slot(iter);
 	ret = bkey_err(k);
 	if (ret)
@@ -577,8 +579,12 @@ int bch2_inode_rm(struct bch_fs *c, u64 inode_nr, bool cached)
 	struct bpos end = POS(inode_nr + 1, 0);
 	struct bch_inode_unpacked inode_u;
 	struct bkey_s_c k;
+	unsigned iter_flags = BTREE_ITER_INTENT;
 	int ret;
 
+	if (cached && c->opts.inodes_use_key_cache)
+		iter_flags |= BTREE_ITER_CACHED;
+
 	bch2_trans_init(&trans, c, 0, 1024);
 
 	/*
@@ -600,11 +606,8 @@ int bch2_inode_rm(struct bch_fs *c, u64 inode_nr, bool cached)
 retry:
 	bch2_trans_begin(&trans);
 
-	iter = bch2_trans_get_iter(&trans, BTREE_ID_inodes, POS(0, inode_nr),
-				   (cached
-				    ? BTREE_ITER_CACHED
-				    : BTREE_ITER_SLOTS)|
-				   BTREE_ITER_INTENT);
+	iter = bch2_trans_get_iter(&trans, BTREE_ID_inodes,
+				   POS(0, inode_nr), iter_flags);
 	k = bch2_btree_iter_peek_slot(iter);
 
 	ret = bkey_err(k);
diff --git a/libbcachefs/opts.c b/libbcachefs/opts.c
index fd3f7cdd..5de29607 100644
--- a/libbcachefs/opts.c
+++ b/libbcachefs/opts.c
@@ -63,7 +63,7 @@ const char * const bch2_member_states[] = {
 
 #undef x
 
-const char * const bch2_d_types[] = {
+const char * const bch2_d_types[DT_MAX] = {
 	[DT_UNKNOWN]	= "unknown",
 	[DT_FIFO]	= "fifo",
 	[DT_CHR]	= "chr",
diff --git a/libbcachefs/opts.h b/libbcachefs/opts.h
index c331535b..ed505857 100644
--- a/libbcachefs/opts.h
+++ b/libbcachefs/opts.h
@@ -173,6 +173,11 @@ enum opt_type {
 	  OPT_BOOL(),							\
 	  BCH_SB_SHARD_INUMS,		false,				\
 	  NULL,		"Shard new inode numbers by CPU id")		\
+	x(inodes_use_key_cache,	u8,					\
+	  OPT_FORMAT|OPT_MOUNT,						\
+	  OPT_BOOL(),							\
+	  BCH_SB_INODES_USE_KEY_CACHE,	true,				\
+	  NULL,		"Use the btree key cache for the inodes btree")	\
 	x(gc_reserve_percent,		u8,				\
 	  OPT_FORMAT|OPT_MOUNT|OPT_RUNTIME,				\
 	  OPT_UINT(5, 21),						\
diff --git a/libbcachefs/sysfs.c b/libbcachefs/sysfs.c
index 84a7acb0..9b1ffbf9 100644
--- a/libbcachefs/sysfs.c
+++ b/libbcachefs/sysfs.c
@@ -171,6 +171,7 @@ read_attribute(btree_cache);
 read_attribute(btree_key_cache);
 read_attribute(btree_transactions);
 read_attribute(stripes_heap);
+read_attribute(open_buckets);
 
 read_attribute(internal_uuid);
 
@@ -409,6 +410,11 @@ SHOW(bch2_fs)
 		return out.pos - buf;
 	}
 
+	if (attr == &sysfs_open_buckets) {
+		bch2_open_buckets_to_text(&out, c);
+		return out.pos - buf;
+	}
+
 	if (attr == &sysfs_compression_stats) {
 		bch2_compression_stats_to_text(&out, c);
 		return out.pos - buf;
@@ -567,6 +573,7 @@ struct attribute *bch2_fs_internal_files[] = {
 	&sysfs_btree_key_cache,
 	&sysfs_btree_transactions,
 	&sysfs_stripes_heap,
+	&sysfs_open_buckets,
 
 	&sysfs_read_realloc_races,
 	&sysfs_extent_migrate_done,
diff --git a/libbcachefs/varint.c b/libbcachefs/varint.c
index a3d252c7..e6a04154 100644
--- a/libbcachefs/varint.c
+++ b/libbcachefs/varint.c
@@ -1,15 +1,80 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/bitops.h>
+#include <linux/string.h>
 #include <asm/unaligned.h>
 
 #include "varint.h"
 
+/**
+ * bch2_varint_encode - encode a variable length integer
+ * @out - destination to encode to
+ * @v	- unsigned integer to encode
+ *
+ * Returns the size in bytes of the encoded integer - at most 9 bytes
+ */
 int bch2_varint_encode(u8 *out, u64 v)
 {
 	unsigned bits = fls64(v|1);
 	unsigned bytes = DIV_ROUND_UP(bits, 7);
 
+	if (likely(bytes < 9)) {
+		v <<= bytes;
+		v |= ~(~0 << (bytes - 1));
+		v = cpu_to_le64(v);
+		memcpy(out, &v, bytes);
+	} else {
+		*out++ = 255;
+		bytes = 9;
+		put_unaligned_le64(v, out);
+	}
+
+	return bytes;
+}
+
+/**
+ * bch2_varint_decode - encode a variable length integer
+ * @in	- varint to decode
+ * @end	- end of buffer to decode from
+ * @out	- on success, decoded integer
+ *
+ * Returns the size in bytes of the decoded integer - or -1 on failure (would
+ * have read past the end of the buffer)
+ */
+int bch2_varint_decode(const u8 *in, const u8 *end, u64 *out)
+{
+	unsigned bytes = likely(in < end)
+		? ffz(*in & 255) + 1
+		: 1;
+	u64 v;
+
+	if (unlikely(in + bytes > end))
+		return -1;
+
+	if (likely(bytes < 9)) {
+		v = 0;
+		memcpy(&v, in, bytes);
+		v = le64_to_cpu(v);
+		v >>= bytes;
+	} else {
+		v = get_unaligned_le64(++in);
+	}
+
+	*out = v;
+	return bytes;
+}
+
+/**
+ * bch2_varint_encode_fast - fast version of bch2_varint_encode
+ *
+ * This version assumes it's always safe to write 8 bytes to @out, even if the
+ * encoded integer would be smaller.
+ */
+int bch2_varint_encode_fast(u8 *out, u64 v)
+{
+	unsigned bits = fls64(v|1);
+	unsigned bytes = DIV_ROUND_UP(bits, 7);
+
 	if (likely(bytes < 9)) {
 		v <<= bytes;
 		v |= ~(~0 << (bytes - 1));
@@ -22,7 +87,13 @@ int bch2_varint_encode(u8 *out, u64 v)
 	return bytes;
 }
 
-int bch2_varint_decode(const u8 *in, const u8 *end, u64 *out)
+/**
+ * bch2_varint_decode_fast - fast version of bch2_varint_decode
+ *
+ * This version assumes that it is safe to read at most 8 bytes past the end of
+ * @end (we still return an error if the varint extends past @end).
+ */
+int bch2_varint_decode_fast(const u8 *in, const u8 *end, u64 *out)
 {
 	u64 v = get_unaligned_le64(in);
 	unsigned bytes = ffz(v & 255) + 1;
diff --git a/libbcachefs/varint.h b/libbcachefs/varint.h
index 8daf8135..92a182fb 100644
--- a/libbcachefs/varint.h
+++ b/libbcachefs/varint.h
@@ -5,4 +5,7 @@
 int bch2_varint_encode(u8 *, u64);
 int bch2_varint_decode(const u8 *, const u8 *, u64 *);
 
+int bch2_varint_encode_fast(u8 *, u64);
+int bch2_varint_decode_fast(const u8 *, const u8 *, u64 *);
+
 #endif /* _BCACHEFS_VARINT_H */