bcachefs: Option code improvements

21 files changed, 374 insertions, 273 deletions

diff --git a/fs/bcachefs/Kconfig b/fs/bcachefs/Kconfig
index ab11eeea98da..6401122ea1fb 100644
--- a/fs/bcachefs/Kconfig
+++ b/fs/bcachefs/Kconfig
@@ -20,11 +20,16 @@ config BCACHEFS_FS
 	The bcachefs filesystem - a modern, copy on write filesystem, with
 	support for multiple devices, compression, checksumming, etc.
 
+config BCACHEFS_POSIX_ACL
+	bool "bcachefs POSIX ACL support"
+	depends on BCACHEFS_FS
+	select FS_POSIX_ACL
+
 config BCACHEFS_DEBUG
 	bool "bcachefs debugging"
 	depends on BCACHEFS_FS
 	---help---
-	Don't select this option unless you're a developer
+	Enables many extra debugging checks and assertions.
 
-	Enables extra debugging tools, allows expensive runtime checks to be
-	turned on.
+	The resulting code will be significantly slower than normal; you
+	probably shouldn't select this option unless you're a developer.
diff --git a/fs/bcachefs/acl.c b/fs/bcachefs/acl.c
index 6b155d8399ea..2dda0debaeb9 100644
--- a/fs/bcachefs/acl.c
+++ b/fs/bcachefs/acl.c
@@ -1,4 +1,4 @@
-#ifndef NO_BCACHEFS_FS
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 
 #include "bcachefs.h"
 
@@ -227,4 +227,4 @@ int bch2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	return ret;
 }
 
-#endif /* NO_BCACHEFS_FS */
+#endif /* CONFIG_BCACHEFS_POSIX_ACL */
diff --git a/fs/bcachefs/acl.h b/fs/bcachefs/acl.h
index 539bca7ec4a0..b721330e2837 100644
--- a/fs/bcachefs/acl.h
+++ b/fs/bcachefs/acl.h
@@ -1,7 +1,7 @@
 #ifndef _BCACHEFS_ACL_H
 #define _BCACHEFS_ACL_H
 
-#ifndef NO_BCACHEFS_FS
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 
 #define BCH_ACL_VERSION	0x0001
 
@@ -54,6 +54,13 @@ struct posix_acl;
 extern struct posix_acl *bch2_get_acl(struct inode *, int);
 extern int bch2_set_acl(struct inode *, struct posix_acl *, int);
 
-#endif /* NO_BCACHEFS_FS */
+#else
+
+static inline int bch2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	return 0;
+}
+
+#endif /* CONFIG_BCACHEFS_POSIX_ACL */
 
 #endif /* _BCACHEFS_ACL_H */
diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index 06b1ee4447d6..945f03ca4c02 100644
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -518,14 +518,11 @@ struct bch_fs {
 		uuid_le		uuid;
 		uuid_le		user_uuid;
 
-		u16		block_size;
-		u16		btree_node_size;
 		u16		encoded_extent_max;
 
 		u8		nr_devices;
 		u8		clean;
 
-		u8		str_hash_type;
 		u8		encryption_type;
 
 		u64		time_base_lo;
@@ -795,7 +792,7 @@ static inline unsigned bucket_bytes(const struct bch_dev *ca)
 
 static inline unsigned block_bytes(const struct bch_fs *c)
 {
-	return c->sb.block_size << 9;
+	return c->opts.block_size << 9;
 }
 
 #endif /* _BCACHEFS_H */
diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
index 463789d65b37..547a4e0bc8f0 100644
--- a/fs/bcachefs/bcachefs_format.h
+++ b/fs/bcachefs/bcachefs_format.h
@@ -9,45 +9,29 @@
 #include <asm/byteorder.h>
 #include <linux/uuid.h>
 
-#define LE32_BITMASK(name, type, field, offset, end)			\
+#define LE_BITMASK(_bits, name, type, field, offset, end)		\
 static const unsigned	name##_OFFSET = offset;				\
 static const unsigned	name##_BITS = (end - offset);			\
-static const __u64	name##_MAX = (1ULL << (end - offset)) - 1;	\
+static const __u##_bits	name##_MAX = (1ULL << (end - offset)) - 1;	\
 									\
 static inline __u64 name(const type *k)					\
 {									\
-	return (__le32_to_cpu(k->field) >> offset) &			\
+	return (__le##_bits##_to_cpu(k->field) >> offset) &		\
 		~(~0ULL << (end - offset));				\
 }									\
 									\
 static inline void SET_##name(type *k, __u64 v)				\
 {									\
-	__u64 new = __le32_to_cpu(k->field);				\
+	__u##_bits new = __le##_bits##_to_cpu(k->field);		\
 									\
 	new &= ~(~(~0ULL << (end - offset)) << offset);			\
 	new |= (v & ~(~0ULL << (end - offset))) << offset;		\
-	k->field = __cpu_to_le32(new);					\
+	k->field = __cpu_to_le##_bits(new);				\
 }
 
-#define LE64_BITMASK(name, type, field, offset, end)			\
-static const unsigned	name##_OFFSET = offset;				\
-static const unsigned	name##_BITS = (end - offset);			\
-static const __u64	name##_MAX = (1ULL << (end - offset)) - 1;	\
-									\
-static inline __u64 name(const type *k)					\
-{									\
-	return (__le64_to_cpu(k->field) >> offset) &			\
-		~(~0ULL << (end - offset));				\
-}									\
-									\
-static inline void SET_##name(type *k, __u64 v)				\
-{									\
-	__u64 new = __le64_to_cpu(k->field);				\
-									\
-	new &= ~(~(~0ULL << (end - offset)) << offset);			\
-	new |= (v & ~(~0ULL << (end - offset))) << offset;		\
-	k->field = __cpu_to_le64(new);					\
-}
+#define LE16_BITMASK(n, t, f, o, e)	LE_BITMASK(16, n, t, f, o, e)
+#define LE32_BITMASK(n, t, f, o, e)	LE_BITMASK(32, n, t, f, o, e)
+#define LE64_BITMASK(n, t, f, o, e)	LE_BITMASK(64, n, t, f, o, e)
 
 struct bkey_format {
 	__u8		key_u64s;
@@ -960,6 +944,8 @@ struct bch_sb {
  *			   algorithm in use, if/when we get more than one
  */
 
+LE16_BITMASK(BCH_SB_BLOCK_SIZE,		struct bch_sb, block_size, 0, 16);
+
 LE64_BITMASK(BCH_SB_INITIALIZED,	struct bch_sb, flags[0],  0,  1);
 LE64_BITMASK(BCH_SB_CLEAN,		struct bch_sb, flags[0],  1,  2);
 LE64_BITMASK(BCH_SB_CSUM_TYPE,		struct bch_sb, flags[0],  2,  8);
@@ -976,7 +962,7 @@ LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,	struct bch_sb, flags[0], 44, 48);
 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT,	struct bch_sb, flags[0], 48, 52);
 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT,	struct bch_sb, flags[0], 52, 56);
 
-/* 56-64 unused, was REPLICAS_HAVE */
+LE64_BITMASK(BCH_SB_POSIX_ACL,		struct bch_sb, flags[0], 56, 57);
 
 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,	struct bch_sb, flags[1],  0,  4);
 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE,	struct bch_sb, flags[1],  4,  8);
diff --git a/fs/bcachefs/btree_cache.h b/fs/bcachefs/btree_cache.h
index ce10a4a9fb60..5e836acda5d6 100644
--- a/fs/bcachefs/btree_cache.h
+++ b/fs/bcachefs/btree_cache.h
@@ -51,7 +51,7 @@ static inline bool btree_node_hashed(struct btree *b)
 
 static inline size_t btree_bytes(struct bch_fs *c)
 {
-	return c->sb.btree_node_size << 9;
+	return c->opts.btree_node_size << 9;
 }
 
 static inline size_t btree_max_u64s(struct bch_fs *c)
@@ -71,7 +71,7 @@ static inline size_t btree_pages(struct bch_fs *c)
 
 static inline unsigned btree_blocks(struct bch_fs *c)
 {
-	return c->sb.btree_node_size >> c->block_bits;
+	return c->opts.btree_node_size >> c->block_bits;
 }
 
 #define BTREE_SPLIT_THRESHOLD(c)		(btree_blocks(c) * 3 / 4)
diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index 2bd2887a7b70..302546f2c2ab 100644
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -116,7 +116,7 @@ static u8 bch2_btree_mark_key(struct bch_fs *c, enum bkey_type type,
 {
 	switch (type) {
 	case BKEY_TYPE_BTREE:
-		bch2_gc_mark_key(c, k, c->sb.btree_node_size, true, flags);
+		bch2_gc_mark_key(c, k, c->opts.btree_node_size, true, flags);
 		return 0;
 	case BKEY_TYPE_EXTENTS:
 		bch2_gc_mark_key(c, k, k.k->size, false, flags);
@@ -386,7 +386,7 @@ static void bch2_mark_pending_btree_node_frees(struct bch_fs *c)
 	for_each_pending_btree_node_free(c, as, d)
 		if (d->index_update_done)
 			__bch2_mark_key(c, bkey_i_to_s_c(&d->key),
-					c->sb.btree_node_size, true,
+					c->opts.btree_node_size, true,
 					&stats, 0,
 					BCH_BUCKET_MARK_MAY_MAKE_UNAVAILABLE);
 	/*
diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index 4e9797f316b1..730ebc43d68d 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -916,7 +916,7 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
 		return 0;
 	}
 
-	if (b->written + sectors > c->sb.btree_node_size) {
+	if (b->written + sectors > c->opts.btree_node_size) {
 		btree_node_error(c, b, "bset past end of btree node");
 		i->u64s = 0;
 		return 0;
@@ -1034,7 +1034,7 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b)
 	if (bch2_meta_read_fault("btree"))
 		goto err;
 
-	while (b->written < c->sb.btree_node_size) {
+	while (b->written < c->opts.btree_node_size) {
 		unsigned sectors, whiteout_u64s = 0;
 
 		if (!b->written) {
@@ -1528,7 +1528,7 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 	BUG_ON(!list_empty(&b->write_blocked));
 	BUG_ON((b->will_make_reachable != NULL) != !b->written);
 
-	BUG_ON(b->written >= c->sb.btree_node_size);
+	BUG_ON(b->written >= c->opts.btree_node_size);
 	BUG_ON(bset_written(b, btree_bset_last(b)));
 	BUG_ON(le64_to_cpu(b->data->magic) != bset_magic(c));
 	BUG_ON(memcmp(&b->data->format, &b->format, sizeof(b->format)));
@@ -1612,7 +1612,7 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 	memset(data + bytes_to_write, 0,
 	       (sectors_to_write << 9) - bytes_to_write);
 
-	BUG_ON(b->written + sectors_to_write > c->sb.btree_node_size);
+	BUG_ON(b->written + sectors_to_write > c->opts.btree_node_size);
 	BUG_ON(BSET_BIG_ENDIAN(i) != CPU_BIG_ENDIAN);
 	BUG_ON(i->seq != b->data->keys.seq);
 
diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 98e856274535..922a48635a6a 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -181,7 +181,7 @@ found:
 	 */
 	replicas = bch2_extent_nr_dirty_ptrs(k);
 	if (replicas)
-		stats->s[replicas - 1].data[S_META] -= c->sb.btree_node_size;
+		stats->s[replicas - 1].data[S_META] -= c->opts.btree_node_size;
 
 	/*
 	 * We're dropping @k from the btree, but it's still live until the
@@ -208,7 +208,7 @@ found:
 		struct bch_fs_usage tmp = { 0 };
 
 		bch2_mark_key(c, bkey_i_to_s_c(&d->key),
-			     -c->sb.btree_node_size, true, b
+			     -c->opts.btree_node_size, true, b
 			     ? gc_pos_btree_node(b)
 			     : gc_pos_btree_root(as->btree_id),
 			     &tmp, 0);
@@ -285,7 +285,7 @@ static void bch2_btree_node_free_ondisk(struct bch_fs *c,
 	BUG_ON(!pending->index_update_done);
 
 	bch2_mark_key(c, bkey_i_to_s_c(&pending->key),
-		     -c->sb.btree_node_size, true,
+		     -c->opts.btree_node_size, true,
 		     gc_phase(GC_PHASE_PENDING_DELETE),
 		     &stats, 0);
 	/*
@@ -337,7 +337,7 @@ static struct btree *__bch2_btree_node_alloc(struct bch_fs *c,
 retry:
 	/* alloc_sectors is weird, I suppose */
 	bkey_extent_init(&tmp.k);
-	tmp.k.k.size = c->sb.btree_node_size,
+	tmp.k.k.size = c->opts.btree_node_size,
 
 	ob = bch2_alloc_sectors(c, &c->btree_write_point,
 			       bkey_i_to_extent(&tmp.k),
@@ -347,7 +347,7 @@ retry:
 	if (IS_ERR(ob))
 		return ERR_CAST(ob);
 
-	if (tmp.k.k.size < c->sb.btree_node_size) {
+	if (tmp.k.k.size < c->opts.btree_node_size) {
 		bch2_open_bucket_put(c, ob);
 		goto retry;
 	}
@@ -491,7 +491,7 @@ static struct btree_reserve *bch2_btree_reserve_get(struct bch_fs *c,
 	struct btree_reserve *reserve;
 	struct btree *b;
 	struct disk_reservation disk_res = { 0, 0 };
-	unsigned sectors = nr_nodes * c->sb.btree_node_size;
+	unsigned sectors = nr_nodes * c->opts.btree_node_size;
 	int ret, disk_res_flags = BCH_DISK_RESERVATION_GC_LOCK_HELD|
 		BCH_DISK_RESERVATION_METADATA;
 
@@ -1035,7 +1035,7 @@ static void bch2_btree_set_root_inmem(struct btree_update *as, struct btree *b)
 	__bch2_btree_set_root_inmem(c, b);
 
 	bch2_mark_key(c, bkey_i_to_s_c(&b->key),
-		      c->sb.btree_node_size, true,
+		      c->opts.btree_node_size, true,
 		      gc_pos_btree_root(b->btree_id),
 		      &stats, 0);
 
@@ -1120,7 +1120,7 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as, struct btree *b
 
 	if (bkey_extent_is_data(&insert->k))
 		bch2_mark_key(c, bkey_i_to_s_c(insert),
-			     c->sb.btree_node_size, true,
+			     c->opts.btree_node_size, true,
 			     gc_pos_btree_node(b), &stats, 0);
 
 	while ((k = bch2_btree_node_iter_peek_all(node_iter, b)) &&
@@ -1901,7 +1901,7 @@ retry:
 		bch2_btree_node_lock_write(b, &iter);
 
 		bch2_mark_key(c, bkey_i_to_s_c(&new_key->k_i),
-			      c->sb.btree_node_size, true,
+			      c->opts.btree_node_size, true,
 			      gc_pos_btree_root(b->btree_id),
 			      &stats, 0);
 		bch2_btree_node_free_index(as, NULL,
diff --git a/fs/bcachefs/btree_update_interior.h b/fs/bcachefs/btree_update_interior.h
index 8f75963bb3ba..e129b24ece76 100644
--- a/fs/bcachefs/btree_update_interior.h
+++ b/fs/bcachefs/btree_update_interior.h
@@ -263,7 +263,7 @@ static inline size_t bch_btree_keys_u64s_remaining(struct bch_fs *c,
 	unsigned used = bset_byte_offset(b, vstruct_end(i)) / sizeof(u64) +
 		b->whiteout_u64s +
 		b->uncompacted_whiteout_u64s;
-	unsigned total = c->sb.btree_node_size << 6;
+	unsigned total = c->opts.btree_node_size << 6;
 
 	EBUG_ON(used > total);
 
diff --git a/fs/bcachefs/compress.c b/fs/bcachefs/compress.c
index fba36c8276a5..c8a03c7f9971 100644
--- a/fs/bcachefs/compress.c
+++ b/fs/bcachefs/compress.c
@@ -423,7 +423,7 @@ void bch2_bio_compress(struct bch_fs *c,
 
 	/* If it's only one block, don't bother trying to compress: */
 	if (*compression_type != BCH_COMPRESSION_NONE &&
-	    bio_sectors(src) > c->sb.block_size &&
+	    bio_sectors(src) > c->opts.block_size &&
 	    !__bio_compress(c, dst, dst_len, src, src_len, compression_type))
 		goto out;
 
diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c
index 33d7e9e28b90..7c641bdab2e2 100644
--- a/fs/bcachefs/extents.c
+++ b/fs/bcachefs/extents.c
@@ -575,7 +575,7 @@ static const char *bch2_btree_ptr_invalid(const struct bch_fs *c,
 
 		extent_for_each_ptr_crc(e, ptr, crc) {
 			reason = extent_ptr_invalid(c, e, ptr,
-						    c->sb.btree_node_size,
+						    c->opts.btree_node_size,
 						    true);
 			if (reason)
 				return reason;
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 72132a8e90fe..6a62ec86b262 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -219,11 +219,13 @@ static struct inode *bch2_vfs_inode_create(struct bch_fs *c,
 
 	inode_init_owner(inode, parent, mode);
 
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 	ret = posix_acl_create(parent, &inode->i_mode, &default_acl, &acl);
 	if (ret) {
 		make_bad_inode(inode);
 		goto err;
 	}
+#endif
 
 	ei = to_bch_ei(inode);
 
@@ -957,8 +959,10 @@ static const struct inode_operations bch_file_inode_operations = {
 	.setattr	= bch2_setattr,
 	.fiemap		= bch2_fiemap,
 	.listxattr	= bch2_xattr_list,
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 	.get_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
+#endif
 };
 
 static const struct inode_operations bch_dir_inode_operations = {
@@ -974,8 +978,10 @@ static const struct inode_operations bch_dir_inode_operations = {
 	.setattr	= bch2_setattr,
 	.tmpfile	= bch2_tmpfile,
 	.listxattr	= bch2_xattr_list,
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 	.get_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
+#endif
 };
 
 static const struct file_operations bch_dir_file_operations = {
@@ -993,15 +999,19 @@ static const struct inode_operations bch_symlink_inode_operations = {
 	.get_link	= page_get_link,
 	.setattr	= bch2_setattr,
 	.listxattr	= bch2_xattr_list,
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 	.get_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
+#endif
 };
 
 static const struct inode_operations bch_special_inode_operations = {
 	.setattr	= bch2_setattr,
 	.listxattr	= bch2_xattr_list,
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
 	.get_acl	= bch2_get_acl,
 	.set_acl	= bch2_set_acl,
+#endif
 };
 
 static const struct address_space_operations bch_address_space_operations = {
@@ -1305,14 +1315,13 @@ static int bch2_remount(struct super_block *sb, int *flags, char *data)
 	struct bch_opts opts = bch2_opts_empty();
 	int ret;
 
-	opts.read_only = (*flags & MS_RDONLY) != 0;
+	opt_set(opts, read_only, (*flags & MS_RDONLY) != 0);
 
 	ret = bch2_parse_mount_opts(&opts, data);
 	if (ret)
 		return ret;
 
-	if (opts.read_only >= 0 &&
-	    opts.read_only != c->opts.read_only) {
+	if (opts.read_only != c->opts.read_only) {
 		const char *err = NULL;
 
 		mutex_lock(&c->state_lock);
@@ -1342,6 +1351,38 @@ static int bch2_remount(struct super_block *sb, int *flags, char *data)
 	return ret;
 }
 
+static int bch2_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct bch_fs *c = root->d_sb->s_fs_info;
+	enum bch_opt_id i;
+
+	for (i = 0; i < bch2_opts_nr; i++) {
+		const struct bch_option *opt = &bch2_opt_table[i];
+		u64 v = bch2_opt_get_by_id(&c->opts, i);
+
+		if (opt->mode < OPT_MOUNT)
+			continue;
+
+		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
+			continue;
+
+		switch (opt->type) {
+		case BCH_OPT_BOOL:
+			seq_printf(seq, ",%s%s", v ? "" : "no", opt->attr.name);
+			break;
+		case BCH_OPT_UINT:
+			seq_printf(seq, ",%s=%llu", opt->attr.name, v);
+			break;
+		case BCH_OPT_STR:
+			seq_printf(seq, ",%s=%s", opt->attr.name, opt->choices[v]);
+			break;
+		}
+	}
+
+	return 0;
+
+}
+
 static const struct super_operations bch_super_operations = {
 	.alloc_inode	= bch2_alloc_inode,
 	.destroy_inode	= bch2_destroy_inode,
@@ -1349,6 +1390,7 @@ static const struct super_operations bch_super_operations = {
 	.evict_inode	= bch2_evict_inode,
 	.sync_fs	= bch2_sync_fs,
 	.statfs		= bch2_statfs,
+	.show_options	= bch2_show_options,
 	.remount_fs	= bch2_remount,
 #if 0
 	.put_super	= bch2_put_super,
@@ -1379,7 +1421,7 @@ static struct dentry *bch2_mount(struct file_system_type *fs_type,
 	unsigned i;
 	int ret;
 
-	opts.read_only = (flags & MS_RDONLY) != 0;
+	opt_set(opts, read_only, (flags & MS_RDONLY) != 0);
 
 	ret = bch2_parse_mount_opts(&opts, data);
 	if (ret)
@@ -1437,10 +1479,10 @@ static struct dentry *bch2_mount(struct file_system_type *fs_type,
 		break;
 	}
 
-	if (opts.posix_acl < 0)
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
+	if (c->opts.acl)
 		sb->s_flags	|= MS_POSIXACL;
-	else
-		sb->s_flags	|= opts.posix_acl ? MS_POSIXACL : 0;
+#endif
 
 	inode = bch2_vfs_inode_get(sb, BCACHEFS_ROOT_INO);
 	if (IS_ERR(inode)) {
diff --git a/fs/bcachefs/inode.c b/fs/bcachefs/inode.c
index 2fb7760cb7de..511ce803782d 100644
--- a/fs/bcachefs/inode.c
+++ b/fs/bcachefs/inode.c
@@ -251,7 +251,7 @@ void bch2_inode_init(struct bch_fs *c, struct bch_inode_unpacked *inode_u,
 	memset(inode_u, 0, sizeof(*inode_u));
 
 	/* ick */
-	inode_u->i_flags |= c->sb.str_hash_type << INODE_STR_HASH_OFFSET;
+	inode_u->i_flags |= c->opts.str_hash << INODE_STR_HASH_OFFSET;
 	get_random_bytes(&inode_u->i_hash_seed, sizeof(inode_u->i_hash_seed));
 
 	inode_u->i_mode		= mode;
diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index 35d69ec82639..b02b6d829f09 100644
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -700,11 +700,11 @@ reread:			sectors_read = min_t(unsigned,
 		case JOURNAL_ENTRY_NONE:
 			if (!saw_bad)
 				return 0;
-			sectors = c->sb.block_size;
+			sectors = c->opts.block_size;
 			goto next_block;
 		case JOURNAL_ENTRY_BAD:
 			saw_bad = true;
-			sectors = c->sb.block_size;
+			sectors = c->opts.block_size;
 			goto next_block;
 		default:
 			return ret;
@@ -1193,7 +1193,7 @@ static enum {
 	j->prev_buf_sectors =
 		vstruct_blocks_plus(buf->data, c->block_bits,
 				    journal_entry_u64s_reserve(buf)) *
-		c->sb.block_size;
+		c->opts.block_size;
 
 	BUG_ON(j->prev_buf_sectors > j->cur_buf_sectors);
 
diff --git a/fs/bcachefs/opts.c b/fs/bcachefs/opts.c
index b5ae5aeb8bfc..c9482151d425 100644
--- a/fs/bcachefs/opts.c
+++ b/fs/bcachefs/opts.c
@@ -66,42 +66,24 @@ const char * const bch2_dev_state[] = {
 	NULL
 };
 
-const struct bch_option bch2_opt_table[] = {
-#define OPT_BOOL()		.type = BCH_OPT_BOOL
-#define OPT_UINT(_min, _max)	.type = BCH_OPT_UINT, .min = _min, .max = _max
-#define OPT_STR(_choices)	.type = BCH_OPT_STR, .choices = _choices
-
-#define BCH_OPT(_name, _mode, _sb_opt, _bits, _type)			\
-	[Opt_##_name] = {						\
-		.name	= #_name,					\
-		.set_sb	= SET_##_sb_opt,				\
-		_type							\
-	},
-	BCH_VISIBLE_OPTS()
-#undef BCH_OPT
-};
-
-static int bch2_opt_lookup(const char *name)
+void bch2_opts_apply(struct bch_opts *dst, struct bch_opts src)
 {
-	const struct bch_option *i;
-
-	for (i = bch2_opt_table;
-	     i < bch2_opt_table + ARRAY_SIZE(bch2_opt_table);
-	     i++)
-		if (!strcmp(name, i->name))
-			return i - bch2_opt_table;
+#define BCH_OPT(_name, ...)						\
+	if (opt_defined(src, _name))					\
+		opt_set(*dst, _name, src._name);
 
-	return -1;
+	BCH_OPTS()
+#undef BCH_OPT
 }
 
-static u64 bch2_opt_get(struct bch_opts *opts, enum bch_opt_id id)
+u64 bch2_opt_get_by_id(const struct bch_opts *opts, enum bch_opt_id id)
 {
 	switch (id) {
 #define BCH_OPT(_name, ...)						\
 	case Opt_##_name:						\
 		return opts->_name;					\
 
-	BCH_VISIBLE_OPTS()
+	BCH_OPTS()
 #undef BCH_OPT
 
 	default:
@@ -109,15 +91,15 @@ static u64 bch2_opt_get(struct bch_opts *opts, enum bch_opt_id id)
 	}
 }
 
-void bch2_opt_set(struct bch_opts *opts, enum bch_opt_id id, u64 v)
+void bch2_opt_set_by_id(struct bch_opts *opts, enum bch_opt_id id, u64 v)
 {
 	switch (id) {
 #define BCH_OPT(_name, ...)						\
 	case Opt_##_name:						\
-		opts->_name = v;					\
+		opt_set(*opts, _name, v);				\
 		break;
 
-	BCH_VISIBLE_OPTS()
+	BCH_OPTS()
 #undef BCH_OPT
 
 	default:
@@ -129,13 +111,13 @@ void bch2_opt_set(struct bch_opts *opts, enum bch_opt_id id, u64 v)
  * Initial options from superblock - here we don't want any options undefined,
  * any options the superblock doesn't specify are set to 0:
  */
-struct bch_opts bch2_sb_opts(struct bch_sb *sb)
+struct bch_opts bch2_opts_from_sb(struct bch_sb *sb)
 {
 	struct bch_opts opts = bch2_opts_empty();
 
-#define BCH_OPT(_name, _mode, _sb_opt, ...)				\
+#define BCH_OPT(_name, _bits, _mode, _type, _sb_opt, _default)		\
 	if (_sb_opt != NO_SB_OPT)					\
-		opts._name = _sb_opt(sb);
+		opt_set(opts, _name, _sb_opt(sb));
 
 	BCH_OPTS()
 #undef BCH_OPT
@@ -143,9 +125,41 @@ struct bch_opts bch2_sb_opts(struct bch_sb *sb)
 	return opts;
 }
 
-static int parse_one_opt(enum bch_opt_id id, const char *val, u64 *res)
+const struct bch_option bch2_opt_table[] = {
+#define OPT_BOOL()		.type = BCH_OPT_BOOL
+#define OPT_UINT(_min, _max)	.type = BCH_OPT_UINT, .min = _min, .max = _max
+#define OPT_STR(_choices)	.type = BCH_OPT_STR, .choices = _choices
+
+#define BCH_OPT(_name, _bits, _mode, _type, _sb_opt, _default)		\
+	[Opt_##_name] = {						\
+		.attr	= {						\
+			.name	= #_name,				\
+			.mode = _mode == OPT_RUNTIME ? 0644 : 0444,	\
+		},							\
+		.mode	= _mode,					\
+		.set_sb	= SET_##_sb_opt,				\
+		_type							\
+	},
+
+	BCH_OPTS()
+#undef BCH_OPT
+};
+
+static int bch2_opt_lookup(const char *name)
+{
+	const struct bch_option *i;
+
+	for (i = bch2_opt_table;
+	     i < bch2_opt_table + ARRAY_SIZE(bch2_opt_table);
+	     i++)
+		if (!strcmp(name, i->attr.name))
+			return i - bch2_opt_table;
+
+	return -1;
+}
+
+int bch2_opt_parse(const struct bch_option *opt, const char *val, u64 *res)
 {
-	const struct bch_option *opt = &bch2_opt_table[id];
 	ssize_t ret;
 
 	switch (opt->type) {
@@ -190,11 +204,11 @@ int bch2_parse_mount_opts(struct bch_opts *opts, char *options)
 		if (val) {
 			id = bch2_opt_lookup(name);
 			if (id < 0)
-				continue;
+				goto bad_opt;
 
-			ret = parse_one_opt(id, val, &v);
+			ret = bch2_opt_parse(&bch2_opt_table[id], val, &v);
 			if (ret < 0)
-				return ret;
+				goto bad_val;
 		} else {
 			id = bch2_opt_lookup(name);
 			v = 1;
@@ -205,47 +219,31 @@ int bch2_parse_mount_opts(struct bch_opts *opts, char *options)
 				v = 0;
 			}
 
-			if (id < 0 ||
-			    bch2_opt_table[id].type != BCH_OPT_BOOL)
-				continue;
-		}
-
-		bch2_opt_set(opts, id, v);
-	}
-
-	return 0;
-}
-
-enum bch_opt_id bch2_parse_sysfs_opt(const char *name, const char *val,
-				    u64 *res)
-{
-	int id = bch2_opt_lookup(name);
-	int ret;
-
-	if (id < 0)
-		return -EINVAL;
-
-	ret = parse_one_opt(id, val, res);
-	if (ret < 0)
-		return ret;
+			if (id < 0)
+				goto bad_opt;
 
-	return id;
-}
+			if (bch2_opt_table[id].type != BCH_OPT_BOOL)
+				goto no_val;
+		}
 
-ssize_t bch2_opt_show(struct bch_opts *opts, const char *name,
-		      char *buf, size_t size)
-{
-	int id = bch2_opt_lookup(name);
-	const struct bch_option *opt;
-	u64 v;
+		if (bch2_opt_table[id].mode < OPT_MOUNT)
+			goto bad_opt;
 
-	if (id < 0)
-		return -EINVAL;
+		if (id == Opt_acl &&
+		    !IS_ENABLED(CONFIG_BCACHEFS_POSIX_ACL))
+			goto bad_opt;
 
-	v = bch2_opt_get(opts, id);
-	opt = &bch2_opt_table[id];
+		bch2_opt_set_by_id(opts, id, v);
+	}
 
-	return opt->type == BCH_OPT_STR
-		? bch2_scnprint_string_list(buf, size, opt->choices, v)
-		: scnprintf(buf, size, "%lli", v);
+	return 0;
+bad_opt:
+	pr_err("Bad mount option %s", name);
+	return -1;
+bad_val:
+	pr_err("Invalid value %s for mount option %s", val, name);
+	return -1;
+no_val:
+	pr_err("Mount option %s requires a value", name);
+	return -1;
 }
diff --git a/fs/bcachefs/opts.h b/fs/bcachefs/opts.h
index 667f629e9ae5..33e3a2c89f1b 100644
--- a/fs/bcachefs/opts.h
+++ b/fs/bcachefs/opts.h
@@ -4,6 +4,7 @@
 #include <linux/bug.h>
 #include <linux/log2.h>
 #include <linux/string.h>
+#include <linux/sysfs.h>
 #include "bcachefs_format.h"
 
 extern const char * const bch2_error_actions[];
@@ -30,101 +31,175 @@ extern const char * const bch2_dev_state[];
 /* dummy option, for options that aren't stored in the superblock */
 LE64_BITMASK(NO_SB_OPT,		struct bch_sb, flags[0], 0, 0);
 
+enum opt_mode {
+	OPT_INTERNAL,
+	OPT_FORMAT,
+	OPT_MOUNT,
+	OPT_RUNTIME,
+};
+
+enum opt_type {
+	BCH_OPT_BOOL,
+	BCH_OPT_UINT,
+	BCH_OPT_STR,
+};
+
 /**
- * BCH_OPT(name, mode, sb_opt, type, ...)
+ * BCH_OPT(name, type, in mem type, mode, sb_opt)
  *
  * @name	- name of mount option, sysfs attribute, and struct bch_opts
  *		  member
  *
- * @mode	- sysfs attr permissions
+ * @mode	- when opt may be set
  *
  * @sb_option	- name of corresponding superblock option
  *
  * @type	- one of OPT_BOOL, OPT_UINT, OPT_STR
  */
 
-enum opt_type {
-	BCH_OPT_BOOL,
-	BCH_OPT_UINT,
-	BCH_OPT_STR,
-};
-
-#define BCH_VISIBLE_OPTS()						\
-	BCH_OPT(errors,			0644,	BCH_SB_ERROR_ACTION,	\
-		s8,  OPT_STR(bch2_error_actions))			\
-	BCH_OPT(metadata_replicas,	0444,	BCH_SB_META_REPLICAS_WANT,\
-		s8,  OPT_UINT(1, BCH_REPLICAS_MAX))			\
-	BCH_OPT(data_replicas,		0444,	BCH_SB_DATA_REPLICAS_WANT,\
-		s8,  OPT_UINT(1, BCH_REPLICAS_MAX))			\
-	BCH_OPT(metadata_replicas_required, 0444, BCH_SB_META_REPLICAS_REQ,\
-		s8,  OPT_UINT(1, BCH_REPLICAS_MAX))			\
-	BCH_OPT(data_replicas_required,	0444,	BCH_SB_DATA_REPLICAS_REQ,\
-		s8,  OPT_UINT(1, BCH_REPLICAS_MAX))			\
-	BCH_OPT(degraded,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(metadata_checksum,	0644,	BCH_SB_META_CSUM_TYPE,	\
-		s8,  OPT_STR(bch2_csum_types))				\
-	BCH_OPT(data_checksum,		0644,	BCH_SB_DATA_CSUM_TYPE,	\
-		s8,  OPT_STR(bch2_csum_types))				\
-	BCH_OPT(compression,		0644,	BCH_SB_COMPRESSION_TYPE,\
-		s8,  OPT_STR(bch2_compression_types))			\
-	BCH_OPT(str_hash,		0644,	BCH_SB_STR_HASH_TYPE,	\
-		s8,  OPT_STR(bch2_str_hash_types))			\
-	BCH_OPT(inodes_32bit,		0644,	BCH_SB_INODE_32BIT,	\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(gc_reserve_percent,	0444,	BCH_SB_GC_RESERVE,	\
-		s8,  OPT_UINT(5, 21))					\
-	BCH_OPT(root_reserve_percent,	0444,	BCH_SB_ROOT_RESERVE,	\
-		s8,  OPT_UINT(0, 100))					\
-	BCH_OPT(wide_macs,		0644,	BCH_SB_128_BIT_MACS,	\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(verbose_recovery,	0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(posix_acl,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(journal_flush_disabled,	0644,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(nofsck,			0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(fix_errors,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(nochanges,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(noreplay,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(norecovery,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(noexcl,			0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(sb,			0444,	NO_SB_OPT,		\
-		s64, OPT_UINT(0, S64_MAX))				\
+/*
+ * XXX: add fields for
+ *  - default value
+ *  - helptext
+ */
 
 #define BCH_OPTS()							\
-	BCH_OPT(read_only,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_OPT(nostart,		0444,	NO_SB_OPT,		\
-		s8,  OPT_BOOL())					\
-	BCH_VISIBLE_OPTS()
+	BCH_OPT(block_size,		u16,	OPT_FORMAT,		\
+		OPT_UINT(1, 128),					\
+		BCH_SB_BLOCK_SIZE,		8)			\
+	BCH_OPT(btree_node_size,	u16,	OPT_FORMAT,		\
+		OPT_UINT(1, 128),					\
+		BCH_SB_BTREE_NODE_SIZE,		512)			\
+	BCH_OPT(errors,			u8,	OPT_RUNTIME,		\
+		OPT_STR(bch2_error_actions),				\
+		BCH_SB_ERROR_ACTION,		BCH_ON_ERROR_RO)	\
+	BCH_OPT(metadata_replicas,	u8,	OPT_MOUNT,		\
+		OPT_UINT(1, BCH_REPLICAS_MAX),				\
+		BCH_SB_META_REPLICAS_WANT,	1)			\
+	BCH_OPT(data_replicas,		u8,	OPT_MOUNT,		\
+		OPT_UINT(1, BCH_REPLICAS_MAX),				\
+		BCH_SB_DATA_REPLICAS_WANT,	1)			\
+	BCH_OPT(metadata_replicas_required, u8,	OPT_MOUNT,		\
+		OPT_UINT(1, BCH_REPLICAS_MAX),				\
+		BCH_SB_META_REPLICAS_REQ,	1)			\
+	BCH_OPT(data_replicas_required, u8,	OPT_MOUNT,		\
+		OPT_UINT(1, BCH_REPLICAS_MAX),				\
+		BCH_SB_DATA_REPLICAS_REQ,	1)			\
+	BCH_OPT(metadata_checksum,	u8,	OPT_RUNTIME,		\
+		OPT_STR(bch2_csum_types),				\
+		BCH_SB_META_CSUM_TYPE,		BCH_CSUM_OPT_CRC32C)	\
+	BCH_OPT(data_checksum,		u8,	OPT_RUNTIME,		\
+		OPT_STR(bch2_csum_types),				\
+		BCH_SB_DATA_CSUM_TYPE,		BCH_CSUM_OPT_CRC32C)	\
+	BCH_OPT(compression,		u8,	OPT_RUNTIME,		\
+		OPT_STR(bch2_compression_types),			\
+		BCH_SB_COMPRESSION_TYPE,	BCH_COMPRESSION_OPT_NONE)\
+	BCH_OPT(str_hash,		u8,	OPT_RUNTIME,		\
+		OPT_STR(bch2_str_hash_types),				\
+		BCH_SB_STR_HASH_TYPE,		BCH_STR_HASH_SIPHASH)	\
+	BCH_OPT(inodes_32bit,		u8,	OPT_RUNTIME,		\
+		OPT_BOOL(),						\
+		BCH_SB_INODE_32BIT,		false)			\
+	BCH_OPT(gc_reserve_percent,	u8,	OPT_MOUNT,		\
+		OPT_UINT(5, 21),					\
+		BCH_SB_GC_RESERVE,		8)			\
+	BCH_OPT(root_reserve_percent,	u8,	OPT_MOUNT,		\
+		OPT_UINT(0, 100),					\
+		BCH_SB_ROOT_RESERVE,		0)			\
+	BCH_OPT(wide_macs,		u8,	OPT_RUNTIME,		\
+		OPT_BOOL(),						\
+		BCH_SB_128_BIT_MACS,		false)			\
+	BCH_OPT(acl,			u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		BCH_SB_POSIX_ACL,		true)			\
+	BCH_OPT(degraded,		u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(verbose_recovery,	u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(journal_flush_disabled, u8,	OPT_RUNTIME,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(nofsck,			u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(fix_errors,		u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(nochanges,		u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(noreplay,		u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(norecovery,		u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(noexcl,			u8,	OPT_MOUNT,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(sb,			u64,	OPT_MOUNT,		\
+		OPT_UINT(0, S64_MAX),					\
+		NO_SB_OPT,			BCH_SB_SECTOR)		\
+	BCH_OPT(read_only,		u8,	OPT_INTERNAL,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)			\
+	BCH_OPT(nostart,		u8,	OPT_INTERNAL,		\
+		OPT_BOOL(),						\
+		NO_SB_OPT,			false)
 
 struct bch_opts {
-#define BCH_OPT(_name, _mode, _sb_opt, _bits, ...)			\
-	_bits	_name;
+#define BCH_OPT(_name, _bits, ...)	unsigned _name##_defined:1;
+	BCH_OPTS()
+#undef BCH_OPT
 
+#define BCH_OPT(_name, _bits, ...)	_bits	_name;
 	BCH_OPTS()
 #undef BCH_OPT
 };
 
-enum bch_opt_id {
-#define BCH_OPT(_name, ...)			\
-	Opt_##_name,
+static const struct bch_opts bch2_opts_default = {
+#define BCH_OPT(_name, _bits, _mode, _type, _sb_opt, _default)		\
+	._name##_defined = true,					\
+	._name = _default,						\
+
+	BCH_OPTS()
+#undef BCH_OPT
+};
 
-	BCH_VISIBLE_OPTS()
+#define opt_defined(_opts, _name)	((_opts)._name##_defined)
+
+#define opt_get(_opts, _name)						\
+	(opt_defined(_opts, _name) ? _opts._name : bch2_opts_default._name)
+
+#define opt_set(_opts, _name, _v)					\
+do {									\
+	(_opts)._name##_defined = true;					\
+	(_opts)._name = _v;						\
+} while (0)
+
+static inline struct bch_opts bch2_opts_empty(void)
+{
+	struct bch_opts opts;
+
+	memset(&opts, 0, sizeof(opts));
+	return opts;
+}
+
+void bch2_opts_apply(struct bch_opts *, struct bch_opts);
+
+enum bch_opt_id {
+#define BCH_OPT(_name, ...)	Opt_##_name,
+	BCH_OPTS()
 #undef BCH_OPT
+	bch2_opts_nr
 };
 
 struct bch_option {
-	const char		*name;
+	struct attribute	attr;
 	void			(*set_sb)(struct bch_sb *, u64);
+	enum opt_mode		mode;
 	enum opt_type		type;
 
 	union {
@@ -140,32 +215,12 @@ struct bch_option {
 
 extern const struct bch_option bch2_opt_table[];
 
-static inline struct bch_opts bch2_opts_empty(void)
-{
-	struct bch_opts ret;
-
-	memset(&ret, 255, sizeof(ret));
-	return ret;
-}
+u64 bch2_opt_get_by_id(const struct bch_opts *, enum bch_opt_id);
+void bch2_opt_set_by_id(struct bch_opts *, enum bch_opt_id, u64);
 
-static inline void bch2_opts_apply(struct bch_opts *dst, struct bch_opts src)
-{
-#define BCH_OPT(_name, ...)			\
-	if (src._name >= 0)						\
-		dst->_name = src._name;
-
-	BCH_OPTS()
-#undef BCH_OPT
-}
-
-#define opt_defined(_opt)		((_opt) >= 0)
-
-void bch2_opt_set(struct bch_opts *, enum bch_opt_id, u64);
-struct bch_opts bch2_sb_opts(struct bch_sb *);
+struct bch_opts bch2_opts_from_sb(struct bch_sb *);
 
+int bch2_opt_parse(const struct bch_option *, const char *, u64 *);
 int bch2_parse_mount_opts(struct bch_opts *, char *);
-enum bch_opt_id bch2_parse_sysfs_opt(const char *, const char *, u64 *);
-
-ssize_t bch2_opt_show(struct bch_opts *, const char *, char *, size_t);
 
 #endif /* _BCACHEFS_OPTS_H */
diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
index 5dce4e2d2101..7b6acbc5bb13 100644
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@ -318,8 +318,10 @@ const char *bch2_sb_validate(struct bcache_superblock *disk_sb)
 	    le64_to_cpu(sb->version) > BCH_SB_VERSION_MAX)
 		return"Unsupported superblock version";
 
-	if (le64_to_cpu(sb->version) < BCH_SB_VERSION_EXTENT_MAX)
+	if (le64_to_cpu(sb->version) < BCH_SB_VERSION_EXTENT_MAX) {
 		SET_BCH_SB_ENCODED_EXTENT_MAX_BITS(sb, 7);
+		SET_BCH_SB_POSIX_ACL(sb, 1);
+	}
 
 	block_size = le16_to_cpu(sb->block_size);
 
@@ -462,11 +464,8 @@ static void bch2_sb_update(struct bch_fs *c)
 
 	c->sb.uuid		= src->uuid;
 	c->sb.user_uuid		= src->user_uuid;
-	c->sb.block_size	= le16_to_cpu(src->block_size);
-	c->sb.btree_node_size	= BCH_SB_BTREE_NODE_SIZE(src);
 	c->sb.nr_devices	= src->nr_devices;
 	c->sb.clean		= BCH_SB_CLEAN(src);
-	c->sb.str_hash_type	= BCH_SB_STR_HASH_TYPE(src);
 	c->sb.encryption_type	= BCH_SB_ENCRYPTION_TYPE(src);
 	c->sb.encoded_extent_max= 1 << BCH_SB_ENCODED_EXTENT_MAX_BITS(src);
 	c->sb.time_base_lo	= le64_to_cpu(src->time_base_lo);
@@ -609,7 +608,7 @@ const char *bch2_read_super(struct bcache_superblock *sb,
 			   struct bch_opts opts,
 			   const char *path)
 {
-	u64 offset = opt_defined(opts.sb) ? opts.sb : BCH_SB_SECTOR;
+	u64 offset = opt_get(opts, sb);
 	struct bch_sb_layout layout;
 	const char *err;
 	unsigned i;
@@ -617,10 +616,10 @@ const char *bch2_read_super(struct bcache_superblock *sb,
 	memset(sb, 0, sizeof(*sb));
 	sb->mode = FMODE_READ;
 
-	if (!(opt_defined(opts.noexcl) && opts.noexcl))
+	if (!opt_get(opts, noexcl))
 		sb->mode |= FMODE_EXCL;
 
-	if (!(opt_defined(opts.nochanges) && opts.nochanges))
+	if (!opt_get(opts, nochanges))
 		sb->mode |= FMODE_WRITE;
 
 	err = bch2_blkdev_open(path, sb->mode, sb, &sb->bdev);
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 9f8df1813db4..9ef81f19c2a8 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -544,15 +544,16 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
 		goto err;
 	}
 
-	c->block_bits		= ilog2(c->sb.block_size);
-
 	mutex_unlock(&c->sb_lock);
 
 	scnprintf(c->name, sizeof(c->name), "%pU", &c->sb.user_uuid);
 
-	bch2_opts_apply(&c->opts, bch2_sb_opts(sb));
+	c->opts = bch2_opts_default;
+	bch2_opts_apply(&c->opts, bch2_opts_from_sb(sb));
 	bch2_opts_apply(&c->opts, opts);
 
+	c->block_bits		= ilog2(c->opts.block_size);
+
 	c->opts.nochanges	|= c->opts.noreplay;
 	c->opts.read_only	|= c->opts.nochanges;
 
@@ -583,7 +584,7 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
 			BIOSET_NEED_BVECS) ||
 	    mempool_init_page_pool(&c->bio_bounce_pages,
 				   max_t(unsigned,
-					 c->sb.btree_node_size,
+					 c->opts.btree_node_size,
 					 c->sb.encoded_extent_max) /
 				   PAGE_SECTORS, 0) ||
 	    !(c->usage_percpu = alloc_percpu(struct bch_fs_usage)) ||
@@ -645,7 +646,8 @@ static const char *__bch2_fs_online(struct bch_fs *c)
 	if (kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) ||
 	    kobject_add(&c->internal, &c->kobj, "internal") ||
 	    kobject_add(&c->opts_dir, &c->kobj, "options") ||
-	    kobject_add(&c->time_stats, &c->kobj, "time_stats"))
+	    kobject_add(&c->time_stats, &c->kobj, "time_stats") ||
+	    bch2_opts_create_sysfs_files(&c->opts_dir))
 		return "error creating sysfs objects";
 
 	mutex_lock(&c->state_lock);
@@ -917,7 +919,7 @@ static const char *bch2_dev_may_add(struct bch_sb *sb, struct bch_fs *c)
 	if (!sb_mi)
 		return "Invalid superblock: member info area missing";
 
-	if (le16_to_cpu(sb->block_size) != c->sb.block_size)
+	if (le16_to_cpu(sb->block_size) != c->opts.block_size)
 		return "mismatched block size";
 
 	if (le16_to_cpu(sb_mi->members[sb->dev_idx].bucket_size) <
@@ -1124,7 +1126,7 @@ static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
 
 	btree_node_reserve_buckets =
 		DIV_ROUND_UP(BTREE_NODE_RESERVE,
-			     ca->mi.bucket_size / c->sb.btree_node_size);
+			     ca->mi.bucket_size / c->opts.btree_node_size);
 
 	if (percpu_ref_init(&ca->ref, bch2_dev_ref_release,
 			    0, GFP_KERNEL) ||
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index ff3deba8dac2..07d9be751d6c 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -194,14 +194,6 @@ read_attribute(data_replicas_have);
 	BCH_DEBUG_PARAMS()
 #undef BCH_DEBUG_PARAM
 
-#define BCH_OPT(_name, _mode, ...)					\
-	static struct attribute sysfs_opt_##_name = {			\
-		.name = #_name,	.mode = _mode,				\
-	};
-
-	BCH_VISIBLE_OPTS()
-#undef BCH_OPT
-
 #define BCH_TIME_STAT(name, frequency_units, duration_units)		\
 	sysfs_time_stats_attribute(name, frequency_units, duration_units);
 	BCH_TIME_STATS()
@@ -528,8 +520,13 @@ SHOW(bch2_fs_opts_dir)
 {
 	char *out = buf, *end = buf + PAGE_SIZE;
 	struct bch_fs *c = container_of(kobj, struct bch_fs, opts_dir);
+	const struct bch_option *opt = container_of(attr, struct bch_option, attr);
+	int id = opt - bch2_opt_table;
+	u64 v = bch2_opt_get_by_id(&c->opts, id);
 
-	out += bch2_opt_show(&c->opts, attr->name, out, end - out);
+	out += opt->type == BCH_OPT_STR
+		? bch2_scnprint_string_list(out, end - out, opt->choices, v)
+		: scnprintf(out, end - out, "%lli", v);
 	out += scnprintf(out, end - out, "\n");
 
 	return out - buf;
@@ -538,15 +535,13 @@ SHOW(bch2_fs_opts_dir)
 STORE(bch2_fs_opts_dir)
 {
 	struct bch_fs *c = container_of(kobj, struct bch_fs, opts_dir);
-	const struct bch_option *opt;
-	int id;
+	const struct bch_option *opt = container_of(attr, struct bch_option, attr);
+	int ret, id = opt - bch2_opt_table;
 	u64 v;
 
-	id = bch2_parse_sysfs_opt(attr->name, buf, &v);
-	if (id < 0)
-		return id;
-
-	opt = &bch2_opt_table[id];
+	ret = bch2_opt_parse(opt, buf, &v);
+	if (ret < 0)
+		return ret;
 
 	mutex_lock(&c->sb_lock);
 
@@ -563,7 +558,7 @@ STORE(bch2_fs_opts_dir)
 		bch2_write_super(c);
 	}
 
-	bch2_opt_set(&c->opts, id, v);
+	bch2_opt_set_by_id(&c->opts, id, v);
 
 	mutex_unlock(&c->sb_lock);
 
@@ -571,15 +566,26 @@ STORE(bch2_fs_opts_dir)
 }
 SYSFS_OPS(bch2_fs_opts_dir);
 
-struct attribute *bch2_fs_opts_dir_files[] = {
-#define BCH_OPT(_name, ...)						\
-	&sysfs_opt_##_name,
+struct attribute *bch2_fs_opts_dir_files[] = { NULL };
 
-	BCH_VISIBLE_OPTS()
-#undef BCH_OPT
+int bch2_opts_create_sysfs_files(struct kobject *kobj)
+{
+	const struct bch_option *i;
+	int ret;
 
-	NULL
-};
+	for (i = bch2_opt_table;
+	     i < bch2_opt_table + bch2_opts_nr;
+	     i++) {
+		if (i->mode == OPT_INTERNAL)
+			continue;
+
+		ret = sysfs_create_file(kobj, &i->attr);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
 
 /* time stats */
 
diff --git a/fs/bcachefs/sysfs.h b/fs/bcachefs/sysfs.h
index a4825056f01e..1ba759fd6e8c 100644
--- a/fs/bcachefs/sysfs.h
+++ b/fs/bcachefs/sysfs.h
@@ -20,6 +20,8 @@ extern struct sysfs_ops bch2_fs_opts_dir_sysfs_ops;
 extern struct sysfs_ops bch2_fs_time_stats_sysfs_ops;
 extern struct sysfs_ops bch2_dev_sysfs_ops;
 
+int bch2_opts_create_sysfs_files(struct kobject *);
+
 #else
 
 static struct attribute *bch2_fs_files[] = {};
@@ -34,6 +36,8 @@ static const struct sysfs_ops bch2_fs_opts_dir_sysfs_ops;
 static const struct sysfs_ops bch2_fs_time_stats_sysfs_ops;
 static const struct sysfs_ops bch2_dev_sysfs_ops;
 
+static inline int bch2_opts_create_sysfs_files(struct kobject *kobj) { return 0; }
+
 #endif /* NO_BCACHEFS_SYSFS */
 
 #endif  /* _BCACHEFS_SYSFS_H_ */