diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
index 1bebba881d89..d801e19cb489 100644
--- a/fs/bcachefs/bcachefs_format.h
+++ b/fs/bcachefs/bcachefs_format.h
@@ -1555,6 +1555,12 @@ enum btree_id {
 	BTREE_ID_NR
 };
 
+/*
+ * Maximum number of btrees that we will _ever_ have under the current scheme,
+ * where we refer to them with bitfields
+ */
+#define BTREE_ID_NR_MAX		64
+
 static inline bool btree_id_is_alloc(enum btree_id id)
 {
 	switch (id) {
diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 5bf98cb8b15d..d3bcb4e4e230 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -332,6 +332,8 @@ static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k
 void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
 			    struct bpos pos, bool key_cache)
 {
+	bch2_trans_verify_not_unlocked(trans);
+
 	struct btree_path *path;
 	struct trans_for_each_path_inorder_iter iter;
 	struct printbuf buf = PRINTBUF;
diff --git a/fs/bcachefs/btree_iter.h b/fs/bcachefs/btree_iter.h
index eab2a25bdc7a..798eb1c47966 100644
--- a/fs/bcachefs/btree_iter.h
+++ b/fs/bcachefs/btree_iter.h
@@ -838,7 +838,7 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 #define drop_locks_do(_trans, _do)					\
 ({									\
 	bch2_trans_unlock(_trans);					\
-	_do ?: bch2_trans_relock(_trans);				\
+	(_do) ?: bch2_trans_relock(_trans);				\
 })
 
 #define allocate_dropping_locks_errcode(_trans, _do)			\
diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index e28d28ac2a13..b469586517a8 100644
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -479,9 +479,8 @@ int bch2_check_fix_ptrs(struct btree_trans *trans,
 
 	percpu_down_read(&c->mark_lock);
 
-	rcu_read_lock();
 	bkey_for_each_ptr_decode(k.k, ptrs_c, p, entry_c) {
-		struct bch_dev *ca = bch2_dev_rcu(c, p.ptr.dev);
+		struct bch_dev *ca = bch2_dev_tryget(c, p.ptr.dev);
 		if (!ca) {
 			if (fsck_err(c, ptr_to_invalid_device,
 				     "pointer to missing device %u\n"
@@ -558,7 +557,7 @@ int bch2_check_fix_ptrs(struct btree_trans *trans,
 			do_update = true;
 
 		if (data_type != BCH_DATA_btree && p.ptr.gen != g->gen)
-			continue;
+			goto next;
 
 		if (fsck_err_on(bucket_data_type_mismatch(g->data_type, data_type),
 				c, ptr_bucket_data_type_mismatch,
@@ -601,8 +600,9 @@ int bch2_check_fix_ptrs(struct btree_trans *trans,
 					 bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
 				do_update = true;
 		}
+next:
+		bch2_dev_put(ca);
 	}
-	rcu_read_unlock();
 
 	if (do_update) {
 		if (flags & BTREE_TRIGGER_is_root) {
@@ -638,9 +638,10 @@ int bch2_check_fix_ptrs(struct btree_trans *trans,
 		} else {
 			struct bkey_ptrs ptrs;
 			union bch_extent_entry *entry;
+
+			rcu_read_lock();
 restart_drop_ptrs:
 			ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
-			rcu_read_lock();
 			bkey_for_each_ptr_decode(bkey_i_to_s(new).k, ptrs, p, entry) {
 				struct bch_dev *ca = bch2_dev_rcu(c, p.ptr.dev);
 				struct bucket *g = PTR_GC_BUCKET(ca, &p.ptr);
@@ -1464,7 +1465,7 @@ int bch2_trans_mark_dev_sbs_flags(struct bch_fs *c,
 	for_each_online_member(c, ca) {
 		int ret = bch2_trans_mark_dev_sb(c, ca, flags);
 		if (ret) {
-			bch2_dev_put(ca);
+			percpu_ref_put(&ca->io_ref);
 			return ret;
 		}
 	}
diff --git a/fs/bcachefs/checksum.c b/fs/bcachefs/checksum.c
index 85198f391e9c..3bd3aba90d8f 100644
--- a/fs/bcachefs/checksum.c
+++ b/fs/bcachefs/checksum.c
@@ -233,7 +233,7 @@ struct bch_csum bch2_checksum(struct bch_fs *c, unsigned type,
 		return ret;
 	}
 	default:
-		BUG();
+		return (struct bch_csum) {};
 	}
 }
 
@@ -307,7 +307,7 @@ static struct bch_csum __bch2_checksum_bio(struct bch_fs *c, unsigned type,
 		return ret;
 	}
 	default:
-		BUG();
+		return (struct bch_csum) {};
 	}
 }
 
@@ -352,8 +352,12 @@ int __bch2_encrypt_bio(struct bch_fs *c, unsigned type,
 		bytes += bv.bv_len;
 	}
 
-	sg_mark_end(sg - 1);
-	return do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
+	if (sg != sgl) {
+		sg_mark_end(sg - 1);
+		return do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
+	}
+
+	return ret;
 }
 
 struct bch_csum bch2_checksum_merge(unsigned type, struct bch_csum a,
@@ -648,26 +652,26 @@ int bch2_decrypt_sb_key(struct bch_fs *c,
 
 static int bch2_alloc_ciphers(struct bch_fs *c)
 {
-	int ret;
-
-	if (!c->chacha20)
-		c->chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
-	ret = PTR_ERR_OR_ZERO(c->chacha20);
+	if (c->chacha20)
+		return 0;
 
+	struct crypto_sync_skcipher *chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
+	int ret = PTR_ERR_OR_ZERO(chacha20);
 	if (ret) {
 		bch_err(c, "error requesting chacha20 module: %s", bch2_err_str(ret));
 		return ret;
 	}
 
-	if (!c->poly1305)
-		c->poly1305 = crypto_alloc_shash("poly1305", 0, 0);
-	ret = PTR_ERR_OR_ZERO(c->poly1305);
-
+	struct crypto_shash *poly1305 = crypto_alloc_shash("poly1305", 0, 0);
+	ret = PTR_ERR_OR_ZERO(poly1305);
 	if (ret) {
 		bch_err(c, "error requesting poly1305 module: %s", bch2_err_str(ret));
+		crypto_free_sync_skcipher(chacha20);
 		return ret;
 	}
 
+	c->chacha20	= chacha20;
+	c->poly1305	= poly1305;
 	return 0;
 }
 
@@ -762,11 +766,11 @@ int bch2_enable_encryption(struct bch_fs *c, bool keyed)
 
 void bch2_fs_encryption_exit(struct bch_fs *c)
 {
-	if (!IS_ERR_OR_NULL(c->poly1305))
+	if (c->poly1305)
 		crypto_free_shash(c->poly1305);
-	if (!IS_ERR_OR_NULL(c->chacha20))
+	if (c->chacha20)
 		crypto_free_sync_skcipher(c->chacha20);
-	if (!IS_ERR_OR_NULL(c->sha256))
+	if (c->sha256)
 		crypto_free_shash(c->sha256);
 }
 
@@ -779,6 +783,7 @@ int bch2_fs_encryption_init(struct bch_fs *c)
 	c->sha256 = crypto_alloc_shash("sha256", 0, 0);
 	ret = PTR_ERR_OR_ZERO(c->sha256);
 	if (ret) {
+		c->sha256 = NULL;
 		bch_err(c, "error requesting sha256 module: %s", bch2_err_str(ret));
 		goto out;
 	}
diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index 6bbf9a7d9e4d..c67460d8205d 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -15,6 +15,9 @@
 
 static unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
 {
+	if (bkey_val_bytes(d.k) < offsetof(struct bch_dirent, d_name))
+		return 0;
+
 	unsigned bkey_u64s = bkey_val_u64s(d.k);
 	unsigned bkey_bytes = bkey_u64s * sizeof(u64);
 	u64 last_u64 = ((u64*)d.v)[bkey_u64s - 1];
diff --git a/fs/bcachefs/fs-io-buffered.c b/fs/bcachefs/fs-io-buffered.c
index b0a33fabadf8..6b69e5cd68dd 100644
--- a/fs/bcachefs/fs-io-buffered.c
+++ b/fs/bcachefs/fs-io-buffered.c
@@ -257,7 +257,6 @@ void bch2_readahead(struct readahead_control *ractl)
 	struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host);
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	struct bch_io_opts opts;
-	struct btree_trans *trans = bch2_trans_get(c);
 	struct folio *folio;
 	struct readpages_iter readpages_iter;
 
@@ -269,6 +268,7 @@ void bch2_readahead(struct readahead_control *ractl)
 
 	bch2_pagecache_add_get(inode);
 
+	struct btree_trans *trans = bch2_trans_get(c);
 	while ((folio = readpage_iter_peek(&readpages_iter))) {
 		unsigned n = min_t(unsigned,
 				   readpages_iter.folios.nr -
@@ -289,10 +289,10 @@ void bch2_readahead(struct readahead_control *ractl)
 			   &readpages_iter);
 		bch2_trans_unlock(trans);
 	}
+	bch2_trans_put(trans);
 
 	bch2_pagecache_add_put(inode);
 
-	bch2_trans_put(trans);
 	darray_exit(&readpages_iter.folios);
 }
 
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index fd851f10d11c..96040a95cf46 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -188,8 +188,7 @@ static struct bch_inode_info *bch2_inode_insert(struct bch_fs *c, struct bch_ino
 	BUG_ON(!old);
 
 	if (unlikely(old != inode)) {
-		__destroy_inode(&inode->v);
-		kmem_cache_free(bch2_inode_cache, inode);
+		discard_new_inode(&inode->v);
 		inode = old;
 	} else {
 		mutex_lock(&c->vfs_inodes_lock);
@@ -1145,6 +1144,8 @@ static int bch2_open(struct inode *vinode, struct file *file)
 			return ret;
 	}
 
+	file->f_mode |= FMODE_CAN_ODIRECT;
+
 	return generic_file_open(vinode, file);
 }
 
@@ -1237,7 +1238,6 @@ static const struct address_space_operations bch_address_space_operations = {
 	.write_end	= bch2_write_end,
 	.invalidate_folio = bch2_invalidate_folio,
 	.release_folio	= bch2_release_folio,
-	.direct_IO	= noop_direct_IO,
 #ifdef CONFIG_MIGRATION
 	.migrate_folio	= filemap_migrate_folio,
 #endif
diff --git a/fs/bcachefs/printbuf.c b/fs/bcachefs/printbuf.c
index 8b0369185f5c..9f529e4c1b16 100644
--- a/fs/bcachefs/printbuf.c
+++ b/fs/bcachefs/printbuf.c
@@ -45,6 +45,13 @@ int bch2_printbuf_make_room(struct printbuf *out, unsigned extra)
 
 	unsigned new_size = roundup_pow_of_two(out->size + extra);
 
+	/* Sanity check... */
+	if (new_size > PAGE_SIZE << MAX_PAGE_ORDER) {
+		out->allocation_failure = true;
+		out->overflow = true;
+		return -ENOMEM;
+	}
+
 	/*
 	 * Note: output buffer must be freeable with kfree(), it's not required
 	 * that the user use printbuf_exit().
diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index 1266916ac03f..cf513fc79ce4 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -35,6 +35,9 @@
 
 void bch2_btree_lost_data(struct bch_fs *c, enum btree_id btree)
 {
+	if (btree >= BTREE_ID_NR_MAX)
+		return;
+
 	u64 b = BIT_ULL(btree);
 
 	if (!(c->sb.btrees_lost_data & b)) {
@@ -808,9 +811,11 @@ int bch2_fs_recovery(struct bch_fs *c)
 	clear_bit(BCH_FS_fsck_running, &c->flags);
 
 	/* fsync if we fixed errors */
-	if (test_bit(BCH_FS_errors_fixed, &c->flags)) {
+	if (test_bit(BCH_FS_errors_fixed, &c->flags) &&
+	    bch2_write_ref_tryget(c, BCH_WRITE_REF_fsync)) {
 		bch2_journal_flush_all_pins(&c->journal);
 		bch2_journal_meta(&c->journal);
+		bch2_write_ref_put(c, BCH_WRITE_REF_fsync);
 	}
 
 	/* If we fixed errors, verify that fs is actually clean now: */
diff --git a/fs/bcachefs/replicas.c b/fs/bcachefs/replicas.c
index bd1d5d085e23..57a1f09cca09 100644
--- a/fs/bcachefs/replicas.c
+++ b/fs/bcachefs/replicas.c
@@ -23,14 +23,12 @@ static int bch2_memcmp(const void *l, const void *r,  const void *priv)
 static void verify_replicas_entry(struct bch_replicas_entry_v1 *e)
 {
 #ifdef CONFIG_BCACHEFS_DEBUG
-	unsigned i;
-
 	BUG_ON(e->data_type >= BCH_DATA_NR);
 	BUG_ON(!e->nr_devs);
 	BUG_ON(e->nr_required > 1 &&
 	       e->nr_required >= e->nr_devs);
 
-	for (i = 0; i + 1 < e->nr_devs; i++)
+	for (unsigned i = 0; i + 1 < e->nr_devs; i++)
 		BUG_ON(e->devs[i] >= e->devs[i + 1]);
 #endif
 }
@@ -192,24 +190,17 @@ cpu_replicas_add_entry(struct bch_fs *c,
 		       struct bch_replicas_cpu *old,
 		       struct bch_replicas_entry_v1 *new_entry)
 {
-	unsigned i;
 	struct bch_replicas_cpu new = {
 		.nr		= old->nr + 1,
 		.entry_size	= max_t(unsigned, old->entry_size,
 					replicas_entry_bytes(new_entry)),
 	};
 
-	for (i = 0; i < new_entry->nr_devs; i++)
-		BUG_ON(!bch2_dev_exists(c, new_entry->devs[i]));
-
-	BUG_ON(!new_entry->data_type);
-	verify_replicas_entry(new_entry);
-
 	new.entries = kcalloc(new.nr, new.entry_size, GFP_KERNEL);
 	if (!new.entries)
 		return new;
 
-	for (i = 0; i < old->nr; i++)
+	for (unsigned i = 0; i < old->nr; i++)
 		memcpy(cpu_replicas_entry(&new, i),
 		       cpu_replicas_entry(old, i),
 		       old->entry_size);
@@ -230,8 +221,6 @@ static inline int __replicas_entry_idx(struct bch_replicas_cpu *r,
 	if (unlikely(entry_size > r->entry_size))
 		return -1;
 
-	verify_replicas_entry(search);
-
 #define entry_cmp(_l, _r)	memcmp(_l, _r, entry_size)
 	idx = eytzinger0_find(r->entries, r->nr, r->entry_size,
 			      entry_cmp, search);
@@ -524,13 +513,16 @@ int bch2_replicas_gc_start(struct bch_fs *c, unsigned typemask)
 	c->replicas_gc.nr		= 0;
 	c->replicas_gc.entry_size	= 0;
 
-	for_each_cpu_replicas_entry(&c->replicas, e)
-		if (!((1 << e->data_type) & typemask)) {
+	for_each_cpu_replicas_entry(&c->replicas, e) {
+		/* Preserve unknown data types */
+		if (e->data_type >= BCH_DATA_NR ||
+		    !((1 << e->data_type) & typemask)) {
 			c->replicas_gc.nr++;
 			c->replicas_gc.entry_size =
 				max_t(unsigned, c->replicas_gc.entry_size,
 				      replicas_entry_bytes(e));
 		}
+	}
 
 	c->replicas_gc.entries = kcalloc(c->replicas_gc.nr,
 					 c->replicas_gc.entry_size,
@@ -542,7 +534,8 @@ int bch2_replicas_gc_start(struct bch_fs *c, unsigned typemask)
 	}
 
 	for_each_cpu_replicas_entry(&c->replicas, e)
-		if (!((1 << e->data_type) & typemask))
+		if (e->data_type >= BCH_DATA_NR ||
+		    !((1 << e->data_type) & typemask))
 			memcpy(cpu_replicas_entry(&c->replicas_gc, i++),
 			       e, c->replicas_gc.entry_size);
 
@@ -998,7 +991,7 @@ unsigned bch2_sb_dev_has_data(struct bch_sb *sb, unsigned dev)
 {
 	struct bch_sb_field_replicas *replicas;
 	struct bch_sb_field_replicas_v0 *replicas_v0;
-	unsigned i, data_has = 0;
+	unsigned data_has = 0;
 
 	replicas = bch2_sb_field_get(sb, replicas);
 	replicas_v0 = bch2_sb_field_get(sb, replicas_v0);
@@ -1006,17 +999,26 @@ unsigned bch2_sb_dev_has_data(struct bch_sb *sb, unsigned dev)
 	if (replicas) {
 		struct bch_replicas_entry_v1 *r;
 
-		for_each_replicas_entry(replicas, r)
-			for (i = 0; i < r->nr_devs; i++)
+		for_each_replicas_entry(replicas, r) {
+			if (r->data_type >= sizeof(data_has) * 8)
+				continue;
+
+			for (unsigned i = 0; i < r->nr_devs; i++)
 				if (r->devs[i] == dev)
 					data_has |= 1 << r->data_type;
+		}
+
 	} else if (replicas_v0) {
 		struct bch_replicas_entry_v0 *r;
 
-		for_each_replicas_entry_v0(replicas_v0, r)
-			for (i = 0; i < r->nr_devs; i++)
+		for_each_replicas_entry_v0(replicas_v0, r) {
+			if (r->data_type >= sizeof(data_has) * 8)
+				continue;
+
+			for (unsigned i = 0; i < r->nr_devs; i++)
 				if (r->devs[i] == dev)
 					data_has |= 1 << r->data_type;
+		}
 	}
 
 
diff --git a/fs/bcachefs/sb-errors_types.h b/fs/bcachefs/sb-errors_types.h
index 87324747351a..666599d3fb9d 100644
--- a/fs/bcachefs/sb-errors_types.h
+++ b/fs/bcachefs/sb-errors_types.h
@@ -273,7 +273,9 @@
 	x(dup_backpointer_to_bad_csum_extent,			265)	\
 	x(btree_bitmap_not_marked,				266)	\
 	x(sb_clean_entry_overrun,				267)	\
-	x(btree_ptr_v2_written_0,				268)
+	x(btree_ptr_v2_written_0,				268)	\
+	x(subvol_snapshot_bad,					269)	\
+	x(subvol_inode_bad,					270)
 
 enum bch_sb_error_id {
 #define x(t, n) BCH_FSCK_ERR_##t = n,
diff --git a/fs/bcachefs/snapshot.h b/fs/bcachefs/snapshot.h
index bd5d74269d15..ab13d8f4b41e 100644
--- a/fs/bcachefs/snapshot.h
+++ b/fs/bcachefs/snapshot.h
@@ -176,12 +176,9 @@ static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ances
 
 static inline bool bch2_snapshot_has_children(struct bch_fs *c, u32 id)
 {
-	const struct snapshot_t *t;
-	bool ret;
-
 	rcu_read_lock();
-	t = snapshot_t(c, id);
-	ret = (t->children[0]|t->children[1]) != 0;
+	const struct snapshot_t *t = snapshot_t(c, id);
+	bool ret = t && (t->children[0]|t->children[1]) != 0;
 	rcu_read_unlock();
 
 	return ret;
diff --git a/fs/bcachefs/subvolume.c b/fs/bcachefs/subvolume.c
index 132213761ef6..dfc9cf305756 100644
--- a/fs/bcachefs/subvolume.c
+++ b/fs/bcachefs/subvolume.c
@@ -210,12 +210,21 @@ int bch2_check_subvol_children(struct bch_fs *c)
 int bch2_subvolume_invalid(struct bch_fs *c, struct bkey_s_c k,
 			   enum bch_validate_flags flags, struct printbuf *err)
 {
+	struct bkey_s_c_subvolume subvol = bkey_s_c_to_subvolume(k);
 	int ret = 0;
 
 	bkey_fsck_err_on(bkey_lt(k.k->p, SUBVOL_POS_MIN) ||
 			 bkey_gt(k.k->p, SUBVOL_POS_MAX), c, err,
 			 subvol_pos_bad,
 			 "invalid pos");
+
+	bkey_fsck_err_on(!subvol.v->snapshot, c, err,
+			 subvol_snapshot_bad,
+			 "invalid snapshot");
+
+	bkey_fsck_err_on(!subvol.v->inode, c, err,
+			 subvol_inode_bad,
+			 "invalid inode");
 fsck_err:
 	return ret;
 }
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 294a9d35a9f2..2206a8dee693 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -551,9 +551,9 @@ static void __bch2_fs_free(struct bch_fs *c)
 	bch2_fs_io_read_exit(c);
 	bch2_fs_buckets_waiting_for_journal_exit(c);
 	bch2_fs_btree_interior_update_exit(c);
-	bch2_fs_btree_iter_exit(c);
 	bch2_fs_btree_key_cache_exit(&c->btree_key_cache);
 	bch2_fs_btree_cache_exit(c);
+	bch2_fs_btree_iter_exit(c);
 	bch2_fs_replicas_exit(c);
 	bch2_fs_journal_exit(&c->journal);
 	bch2_io_clock_exit(&c->io_clock[WRITE]);