X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libbcachefs%2Fsuper-io.c;h=55926b81eede63596f7a48f6daaa363bede4d504;hb=b5fd066153c40a70a29caa1ea7987723ab687763;hp=de8d49e3ef02d7e1fbdded96ed8ff3bcc49f11d7;hpb=b422ff58ba8eedcfef3b67b66468660f07b0cfc1;p=bcachefs-tools-debian

diff --git a/libbcachefs/super-io.c b/libbcachefs/super-io.c
index de8d49e..55926b8 100644
--- a/libbcachefs/super-io.c
+++ b/libbcachefs/super-io.c
@@ -1,25 +1,73 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include "bcachefs.h"
-#include "btree_update_interior.h"
-#include "buckets.h"
 #include "checksum.h"
+#include "counters.h"
 #include "disk_groups.h"
 #include "ec.h"
 #include "error.h"
-#include "io.h"
 #include "journal.h"
-#include "journal_io.h"
+#include "journal_sb.h"
 #include "journal_seq_blacklist.h"
+#include "recovery.h"
 #include "replicas.h"
 #include "quota.h"
+#include "sb-clean.h"
+#include "sb-downgrade.h"
+#include "sb-errors.h"
+#include "sb-members.h"
 #include "super-io.h"
 #include "super.h"
+#include "trace.h"
 #include "vstructs.h"
 
 #include <linux/backing-dev.h>
 #include <linux/sort.h>
 
+static const struct blk_holder_ops bch2_sb_handle_bdev_ops = {
+};
+
+struct bch2_metadata_version {
+	u16		version;
+	const char	*name;
+};
+
+static const struct bch2_metadata_version bch2_metadata_versions[] = {
+#define x(n, v) {		\
+	.version = v,				\
+	.name = #n,				\
+},
+	BCH_METADATA_VERSIONS()
+#undef x
+};
+
+void bch2_version_to_text(struct printbuf *out, unsigned v)
+{
+	const char *str = "(unknown version)";
+
+	for (unsigned i = 0; i < ARRAY_SIZE(bch2_metadata_versions); i++)
+		if (bch2_metadata_versions[i].version == v) {
+			str = bch2_metadata_versions[i].name;
+			break;
+		}
+
+	prt_printf(out, "%u.%u: %s", BCH_VERSION_MAJOR(v), BCH_VERSION_MINOR(v), str);
+}
+
+unsigned bch2_latest_compatible_version(unsigned v)
+{
+	if (!BCH_VERSION_MAJOR(v))
+		return v;
+
+	for (unsigned i = 0; i < ARRAY_SIZE(bch2_metadata_versions); i++)
+		if (bch2_metadata_versions[i].version > v &&
+		    BCH_VERSION_MAJOR(bch2_metadata_versions[i].version) ==
+		    BCH_VERSION_MAJOR(v))
+			v = bch2_metadata_versions[i].version;
+
+	return v;
+}
+
 const char * const bch2_sb_fields[] = {
 #define x(name, nr)	#name,
 	BCH_SB_FIELDS()
@@ -27,14 +75,12 @@ const char * const bch2_sb_fields[] = {
 	NULL
 };
 
-static const char *bch2_sb_field_validate(struct bch_sb *,
-					  struct bch_sb_field *);
+static int bch2_sb_field_validate(struct bch_sb *, struct bch_sb_field *,
+				  struct printbuf *);
 
-struct bch_sb_field *bch2_sb_field_get(struct bch_sb *sb,
+struct bch_sb_field *bch2_sb_field_get_id(struct bch_sb *sb,
 				      enum bch_sb_field_type type)
 {
-	struct bch_sb_field *f;
-
 	/* XXX: need locking around superblock to access optional fields */
 
 	vstruct_for_each(sb, f)
@@ -85,7 +131,7 @@ static struct bch_sb_field *__bch2_sb_field_resize(struct bch_sb_handle *sb,
 void bch2_sb_field_delete(struct bch_sb_handle *sb,
 			  enum bch_sb_field_type type)
 {
-	struct bch_sb_field *f = bch2_sb_field_get(sb->sb, type);
+	struct bch_sb_field *f = bch2_sb_field_get_id(sb->sb, type);
 
 	if (f)
 		__bch2_sb_field_resize(sb, f, 0);
@@ -95,10 +141,11 @@ void bch2_sb_field_delete(struct bch_sb_handle *sb,
 
 void bch2_free_super(struct bch_sb_handle *sb)
 {
-	if (sb->bio)
-		bio_put(sb->bio);
+	kfree(sb->bio);
 	if (!IS_ERR_OR_NULL(sb->bdev))
-		blkdev_put(sb->bdev, sb->mode);
+		blkdev_put(sb->bdev, sb->holder);
+	kfree(sb->holder);
+	kfree(sb->sb_name);
 
 	kfree(sb->sb);
 	memset(sb, 0, sizeof(*sb));
@@ -119,15 +166,17 @@ int bch2_sb_realloc(struct bch_sb_handle *sb, unsigned u64s)
 	if (sb->sb && sb->buffer_size >= new_buffer_size)
 		return 0;
 
-	if (sb->have_layout) {
+	if (sb->sb && sb->have_layout) {
 		u64 max_bytes = 512 << sb->sb->layout.sb_max_size_bits;
 
 		if (new_bytes > max_bytes) {
-			char buf[BDEVNAME_SIZE];
+			struct printbuf buf = PRINTBUF;
 
-			pr_err("%s: superblock too big: want %zu but have %llu",
-			       bdevname(sb->bdev, buf), new_bytes, max_bytes);
-			return -ENOSPC;
+			prt_bdevname(&buf, sb->bdev);
+			prt_printf(&buf, ": superblock too big: want %zu but have %llu", new_bytes, max_bytes);
+			pr_err("%s", buf.buf);
+			printbuf_exit(&buf);
+			return -BCH_ERR_ENOSPC_sb;
 		}
 	}
 
@@ -135,34 +184,37 @@ int bch2_sb_realloc(struct bch_sb_handle *sb, unsigned u64s)
 		return 0;
 
 	if (dynamic_fault("bcachefs:add:super_realloc"))
-		return -ENOMEM;
+		return -BCH_ERR_ENOMEM_sb_realloc_injected;
+
+	new_sb = krealloc(sb->sb, new_buffer_size, GFP_NOFS|__GFP_ZERO);
+	if (!new_sb)
+		return -BCH_ERR_ENOMEM_sb_buf_realloc;
+
+	sb->sb = new_sb;
 
 	if (sb->have_bio) {
-		bio = bio_kmalloc(GFP_KERNEL,
-			DIV_ROUND_UP(new_buffer_size, PAGE_SIZE));
+		unsigned nr_bvecs = buf_pages(sb->sb, new_buffer_size);
+
+		bio = bio_kmalloc(nr_bvecs, GFP_KERNEL);
 		if (!bio)
-			return -ENOMEM;
+			return -BCH_ERR_ENOMEM_sb_bio_realloc;
+
+		bio_init(bio, NULL, bio->bi_inline_vecs, nr_bvecs, 0);
 
-		if (sb->bio)
-			bio_put(sb->bio);
+		kfree(sb->bio);
 		sb->bio = bio;
 	}
 
-	new_sb = krealloc(sb->sb, new_buffer_size, GFP_NOFS|__GFP_ZERO);
-	if (!new_sb)
-		return -ENOMEM;
-
-	sb->sb = new_sb;
 	sb->buffer_size = new_buffer_size;
 
 	return 0;
 }
 
-struct bch_sb_field *bch2_sb_field_resize(struct bch_sb_handle *sb,
+struct bch_sb_field *bch2_sb_field_resize_id(struct bch_sb_handle *sb,
 					  enum bch_sb_field_type type,
 					  unsigned u64s)
 {
-	struct bch_sb_field *f = bch2_sb_field_get(sb->sb, type);
+	struct bch_sb_field *f = bch2_sb_field_get_id(sb->sb, type);
 	ssize_t old_u64s = f ? le32_to_cpu(f->u64s) : 0;
 	ssize_t d = -old_u64s + u64s;
 
@@ -171,53 +223,69 @@ struct bch_sb_field *bch2_sb_field_resize(struct bch_sb_handle *sb,
 
 	if (sb->fs_sb) {
 		struct bch_fs *c = container_of(sb, struct bch_fs, disk_sb);
-		struct bch_dev *ca;
-		unsigned i;
 
 		lockdep_assert_held(&c->sb_lock);
 
 		/* XXX: we're not checking that offline device have enough space */
 
-		for_each_online_member(ca, c, i) {
-			struct bch_sb_handle *sb = &ca->disk_sb;
+		for_each_online_member(c, ca) {
+			struct bch_sb_handle *dev_sb = &ca->disk_sb;
 
-			if (bch2_sb_realloc(sb, le32_to_cpu(sb->sb->u64s) + d)) {
+			if (bch2_sb_realloc(dev_sb, le32_to_cpu(dev_sb->sb->u64s) + d)) {
 				percpu_ref_put(&ca->ref);
 				return NULL;
 			}
 		}
 	}
 
-	f = bch2_sb_field_get(sb->sb, type);
+	f = bch2_sb_field_get_id(sb->sb, type);
 	f = __bch2_sb_field_resize(sb, f, u64s);
 	if (f)
 		f->type = cpu_to_le32(type);
 	return f;
 }
 
-/* Superblock validate: */
-
-static inline void __bch2_sb_layout_size_assert(void)
+struct bch_sb_field *bch2_sb_field_get_minsize_id(struct bch_sb_handle *sb,
+						  enum bch_sb_field_type type,
+						  unsigned u64s)
 {
-	BUILD_BUG_ON(sizeof(struct bch_sb_layout) != 512);
+	struct bch_sb_field *f = bch2_sb_field_get_id(sb->sb, type);
+
+	if (!f || le32_to_cpu(f->u64s) < u64s)
+		f = bch2_sb_field_resize_id(sb, type, u64s);
+	return f;
 }
 
-static const char *validate_sb_layout(struct bch_sb_layout *layout)
+/* Superblock validate: */
+
+static int validate_sb_layout(struct bch_sb_layout *layout, struct printbuf *out)
 {
 	u64 offset, prev_offset, max_sectors;
 	unsigned i;
 
-	if (uuid_le_cmp(layout->magic, BCACHE_MAGIC))
-		return "Not a bcachefs superblock layout";
+	BUILD_BUG_ON(sizeof(struct bch_sb_layout) != 512);
+
+	if (!uuid_equal(&layout->magic, &BCACHE_MAGIC) &&
+	    !uuid_equal(&layout->magic, &BCHFS_MAGIC)) {
+		prt_printf(out, "Not a bcachefs superblock layout");
+		return -BCH_ERR_invalid_sb_layout;
+	}
 
-	if (layout->layout_type != 0)
-		return "Invalid superblock layout type";
+	if (layout->layout_type != 0) {
+		prt_printf(out, "Invalid superblock layout type %u",
+		       layout->layout_type);
+		return -BCH_ERR_invalid_sb_layout_type;
+	}
 
-	if (!layout->nr_superblocks)
-		return "Invalid superblock layout: no superblocks";
+	if (!layout->nr_superblocks) {
+		prt_printf(out, "Invalid superblock layout: no superblocks");
+		return -BCH_ERR_invalid_sb_layout_nr_superblocks;
+	}
 
-	if (layout->nr_superblocks > ARRAY_SIZE(layout->sb_offset))
-		return "Invalid superblock layout: too many superblocks";
+	if (layout->nr_superblocks > ARRAY_SIZE(layout->sb_offset)) {
+		prt_printf(out, "Invalid superblock layout: too many superblocks");
+		return -BCH_ERR_invalid_sb_layout_nr_superblocks;
+	}
 
 	max_sectors = 1 << layout->sb_max_size_bits;
 
@@ -226,136 +294,205 @@ static const char *validate_sb_layout(struct bch_sb_layout *layout)
 	for (i = 1; i < layout->nr_superblocks; i++) {
 		offset = le64_to_cpu(layout->sb_offset[i]);
 
-		if (offset < prev_offset + max_sectors)
-			return "Invalid superblock layout: superblocks overlap";
+		if (offset < prev_offset + max_sectors) {
+			prt_printf(out, "Invalid superblock layout: superblocks overlap\n"
+			       "  (sb %u ends at %llu next starts at %llu",
+			       i - 1, prev_offset + max_sectors, offset);
+			return -BCH_ERR_invalid_sb_layout_superblocks_overlap;
+		}
 		prev_offset = offset;
 	}
 
-	return NULL;
+	return 0;
 }
 
-const char *bch2_sb_validate(struct bch_sb_handle *disk_sb)
+static int bch2_sb_compatible(struct bch_sb *sb, struct printbuf *out)
 {
-	struct bch_sb *sb = disk_sb->sb;
-	struct bch_sb_field *f;
-	struct bch_sb_field_members *mi;
-	const char *err;
-	u32 version, version_min;
-	u16 block_size;
+	u16 version		= le16_to_cpu(sb->version);
+	u16 version_min		= le16_to_cpu(sb->version_min);
+
+	if (!bch2_version_compatible(version)) {
+		prt_str(out, "Unsupported superblock version ");
+		bch2_version_to_text(out, version);
+		prt_str(out, " (min ");
+		bch2_version_to_text(out, bcachefs_metadata_version_min);
+		prt_str(out, ", max ");
+		bch2_version_to_text(out, bcachefs_metadata_version_current);
+		prt_str(out, ")");
+		return -BCH_ERR_invalid_sb_version;
+	}
 
-	version		= le16_to_cpu(sb->version);
-	version_min	= version >= bcachefs_metadata_version_new_versioning
-		? le16_to_cpu(sb->version_min)
-		: version;
+	if (!bch2_version_compatible(version_min)) {
+		prt_str(out, "Unsupported superblock version_min ");
+		bch2_version_to_text(out, version_min);
+		prt_str(out, " (min ");
+		bch2_version_to_text(out, bcachefs_metadata_version_min);
+		prt_str(out, ", max ");
+		bch2_version_to_text(out, bcachefs_metadata_version_current);
+		prt_str(out, ")");
+		return -BCH_ERR_invalid_sb_version;
+	}
 
-	if (version    >= bcachefs_metadata_version_max ||
-	    version_min < bcachefs_metadata_version_min)
-		return "Unsupported superblock version";
+	if (version_min > version) {
+		prt_str(out, "Bad minimum version ");
+		bch2_version_to_text(out, version_min);
+		prt_str(out, ", greater than version field ");
+		bch2_version_to_text(out, version);
+		return -BCH_ERR_invalid_sb_version;
+	}
 
-	if (version_min > version)
-		return "Bad minimum version";
+	return 0;
+}
+
+static int bch2_sb_validate(struct bch_sb_handle *disk_sb, struct printbuf *out,
+			    int rw)
+{
+	struct bch_sb *sb = disk_sb->sb;
+	struct bch_sb_field_members_v1 *mi;
+	enum bch_opt_id opt_id;
+	u16 block_size;
+	int ret;
+
+	ret = bch2_sb_compatible(sb, out);
+	if (ret)
+		return ret;
 
 	if (sb->features[1] ||
-	    (le64_to_cpu(sb->features[0]) & (~0ULL << BCH_FEATURE_NR)))
-		return "Filesystem has incompatible features";
+	    (le64_to_cpu(sb->features[0]) & (~0ULL << BCH_FEATURE_NR))) {
+		prt_printf(out, "Filesystem has incompatible features");
+		return -BCH_ERR_invalid_sb_features;
+	}
 
 	block_size = le16_to_cpu(sb->block_size);
 
-	if (!is_power_of_2(block_size) ||
-	    block_size > PAGE_SECTORS)
-		return "Bad block size";
+	if (block_size > PAGE_SECTORS) {
+		prt_printf(out, "Block size too big (got %u, max %u)",
+		       block_size, PAGE_SECTORS);
+		return -BCH_ERR_invalid_sb_block_size;
+	}
 
-	if (bch2_is_zero(sb->user_uuid.b, sizeof(uuid_le)))
-		return "Bad user UUID";
+	if (bch2_is_zero(sb->user_uuid.b, sizeof(sb->user_uuid))) {
+		prt_printf(out, "Bad user UUID (got zeroes)");
+		return -BCH_ERR_invalid_sb_uuid;
+	}
 
-	if (bch2_is_zero(sb->uuid.b, sizeof(uuid_le)))
-		return "Bad internal UUID";
+	if (bch2_is_zero(sb->uuid.b, sizeof(sb->uuid))) {
+		prt_printf(out, "Bad internal UUID (got zeroes)");
+		return -BCH_ERR_invalid_sb_uuid;
+	}
 
 	if (!sb->nr_devices ||
-	    sb->nr_devices <= sb->dev_idx ||
-	    sb->nr_devices > BCH_SB_MEMBERS_MAX)
-		return "Bad number of member devices";
-
-	if (!BCH_SB_META_REPLICAS_WANT(sb) ||
-	    BCH_SB_META_REPLICAS_WANT(sb) > BCH_REPLICAS_MAX)
-		return "Invalid number of metadata replicas";
-
-	if (!BCH_SB_META_REPLICAS_REQ(sb) ||
-	    BCH_SB_META_REPLICAS_REQ(sb) > BCH_REPLICAS_MAX)
-		return "Invalid number of metadata replicas";
-
-	if (!BCH_SB_DATA_REPLICAS_WANT(sb) ||
-	    BCH_SB_DATA_REPLICAS_WANT(sb) > BCH_REPLICAS_MAX)
-		return "Invalid number of data replicas";
-
-	if (!BCH_SB_DATA_REPLICAS_REQ(sb) ||
-	    BCH_SB_DATA_REPLICAS_REQ(sb) > BCH_REPLICAS_MAX)
-		return "Invalid number of data replicas";
+	    sb->nr_devices > BCH_SB_MEMBERS_MAX) {
+		prt_printf(out, "Bad number of member devices %u (max %u)",
+		       sb->nr_devices, BCH_SB_MEMBERS_MAX);
+		return -BCH_ERR_invalid_sb_too_many_members;
+	}
 
-	if (BCH_SB_META_CSUM_TYPE(sb) >= BCH_CSUM_OPT_NR)
-		return "Invalid metadata checksum type";
+	if (sb->dev_idx >= sb->nr_devices) {
+		prt_printf(out, "Bad dev_idx (got %u, nr_devices %u)",
+		       sb->dev_idx, sb->nr_devices);
+		return -BCH_ERR_invalid_sb_dev_idx;
+	}
 
-	if (BCH_SB_DATA_CSUM_TYPE(sb) >= BCH_CSUM_OPT_NR)
-		return "Invalid metadata checksum type";
+	if (!sb->time_precision ||
+	    le32_to_cpu(sb->time_precision) > NSEC_PER_SEC) {
+		prt_printf(out, "Invalid time precision: %u (min 1, max %lu)",
+		       le32_to_cpu(sb->time_precision), NSEC_PER_SEC);
+		return -BCH_ERR_invalid_sb_time_precision;
+	}
 
-	if (BCH_SB_COMPRESSION_TYPE(sb) >= BCH_COMPRESSION_OPT_NR)
-		return "Invalid compression type";
+	if (rw == READ) {
+		/*
+		 * Been seeing a bug where these are getting inexplicably
+		 * zeroed, so we're now validating them, but we have to be
+		 * careful not to preven people's filesystems from mounting:
+		 */
+		if (!BCH_SB_JOURNAL_FLUSH_DELAY(sb))
+			SET_BCH_SB_JOURNAL_FLUSH_DELAY(sb, 1000);
+		if (!BCH_SB_JOURNAL_RECLAIM_DELAY(sb))
+			SET_BCH_SB_JOURNAL_RECLAIM_DELAY(sb, 1000);
+
+		if (!BCH_SB_VERSION_UPGRADE_COMPLETE(sb))
+			SET_BCH_SB_VERSION_UPGRADE_COMPLETE(sb, le16_to_cpu(sb->version));
+	}
 
-	if (!BCH_SB_BTREE_NODE_SIZE(sb))
-		return "Btree node size not set";
+	for (opt_id = 0; opt_id < bch2_opts_nr; opt_id++) {
+		const struct bch_option *opt = bch2_opt_table + opt_id;
 
-	if (!is_power_of_2(BCH_SB_BTREE_NODE_SIZE(sb)))
-		return "Btree node size not a power of two";
+		if (opt->get_sb != BCH2_NO_SB_OPT) {
+			u64 v = bch2_opt_from_sb(sb, opt_id);
 
-	if (BCH_SB_GC_RESERVE(sb) < 5)
-		return "gc reserve percentage too small";
+			prt_printf(out, "Invalid option ");
+			ret = bch2_opt_validate(opt, v, out);
+			if (ret)
+				return ret;
 
-	if (!sb->time_precision ||
-	    le32_to_cpu(sb->time_precision) > NSEC_PER_SEC)
-		return "invalid time precision";
+			printbuf_reset(out);
+		}
+	}
 
 	/* validate layout */
-	err = validate_sb_layout(&sb->layout);
-	if (err)
-		return err;
+	ret = validate_sb_layout(&sb->layout, out);
+	if (ret)
+		return ret;
 
 	vstruct_for_each(sb, f) {
-		if (!f->u64s)
-			return "Invalid superblock: invalid optional field";
+		if (!f->u64s) {
+			prt_printf(out, "Invalid superblock: optional field with size 0 (type %u)",
+			       le32_to_cpu(f->type));
+			return -BCH_ERR_invalid_sb_field_size;
+		}
 
-		if (vstruct_next(f) > vstruct_last(sb))
-			return "Invalid superblock: invalid optional field";
+		if (vstruct_next(f) > vstruct_last(sb)) {
+			prt_printf(out, "Invalid superblock: optional field extends past end of superblock (type %u)",
+			       le32_to_cpu(f->type));
+			return -BCH_ERR_invalid_sb_field_size;
+		}
 	}
 
 	/* members must be validated first: */
-	mi = bch2_sb_get_members(sb);
-	if (!mi)
-		return "Invalid superblock: member info area missing";
+	mi = bch2_sb_field_get(sb, members_v1);
+	if (!mi) {
+		prt_printf(out, "Invalid superblock: member info area missing");
+		return -BCH_ERR_invalid_sb_members_missing;
+	}
 
-	err = bch2_sb_field_validate(sb, &mi->field);
-	if (err)
-		return err;
+	ret = bch2_sb_field_validate(sb, &mi->field, out);
+	if (ret)
+		return ret;
 
 	vstruct_for_each(sb, f) {
-		if (le32_to_cpu(f->type) == BCH_SB_FIELD_members)
+		if (le32_to_cpu(f->type) == BCH_SB_FIELD_members_v1)
 			continue;
 
-		err = bch2_sb_field_validate(sb, f);
-		if (err)
-			return err;
+		ret = bch2_sb_field_validate(sb, f, out);
+		if (ret)
+			return ret;
 	}
 
-	return NULL;
+	return 0;
 }
 
 /* device open: */
 
+static unsigned long le_ulong_to_cpu(unsigned long v)
+{
+	return sizeof(unsigned long) == 8
+		? le64_to_cpu(v)
+		: le32_to_cpu(v);
+}
+
+static void le_bitvector_to_cpu(unsigned long *dst, unsigned long *src, unsigned nr)
+{
+	BUG_ON(nr & (BITS_PER_TYPE(long) - 1));
+
+	for (unsigned i = 0; i < BITS_TO_LONGS(nr); i++)
+		dst[i] = le_ulong_to_cpu(src[i]);
+}
+
 static void bch2_sb_update(struct bch_fs *c)
 {
 	struct bch_sb *src = c->disk_sb.sb;
-	struct bch_sb_field_members *mi = bch2_sb_get_members(src);
-	struct bch_dev *ca;
-	unsigned i;
 
 	lockdep_assert_held(&c->sb_lock);
 
@@ -363,21 +500,36 @@ static void bch2_sb_update(struct bch_fs *c)
 	c->sb.user_uuid		= src->user_uuid;
 	c->sb.version		= le16_to_cpu(src->version);
 	c->sb.version_min	= le16_to_cpu(src->version_min);
+	c->sb.version_upgrade_complete = BCH_SB_VERSION_UPGRADE_COMPLETE(src);
 	c->sb.nr_devices	= src->nr_devices;
 	c->sb.clean		= BCH_SB_CLEAN(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);
+
+	c->sb.nsec_per_time_unit = le32_to_cpu(src->time_precision);
+	c->sb.time_units_per_sec = NSEC_PER_SEC / c->sb.nsec_per_time_unit;
+
+	/* XXX this is wrong, we need a 96 or 128 bit integer type */
+	c->sb.time_base_lo	= div_u64(le64_to_cpu(src->time_base_lo),
+					  c->sb.nsec_per_time_unit);
 	c->sb.time_base_hi	= le32_to_cpu(src->time_base_hi);
-	c->sb.time_precision	= le32_to_cpu(src->time_precision);
+
 	c->sb.features		= le64_to_cpu(src->features[0]);
 	c->sb.compat		= le64_to_cpu(src->compat[0]);
 
-	for_each_member_device(ca, c, i)
-		ca->mi = bch2_mi_to_cpu(mi->members + i);
+	memset(c->sb.errors_silent, 0, sizeof(c->sb.errors_silent));
+
+	struct bch_sb_field_ext *ext = bch2_sb_field_get(src, ext);
+	if (ext)
+		le_bitvector_to_cpu(c->sb.errors_silent, (void *) ext->errors_silent,
+				    sizeof(c->sb.errors_silent) * 8);
+
+	for_each_member_device(c, ca) {
+		struct bch_member m = bch2_sb_member_get(src, ca->dev_idx);
+		ca->mi = bch2_mi_to_cpu(&m);
+	}
 }
 
-static void __copy_super(struct bch_sb_handle *dst_handle, struct bch_sb *src)
+static int __copy_super(struct bch_sb_handle *dst_handle, struct bch_sb *src)
 {
 	struct bch_sb_field *src_f, *dst_f;
 	struct bch_sb *dst = dst_handle->sb;
@@ -396,48 +548,54 @@ static void __copy_super(struct bch_sb_handle *dst_handle, struct bch_sb *src)
 	dst->time_base_lo	= src->time_base_lo;
 	dst->time_base_hi	= src->time_base_hi;
 	dst->time_precision	= src->time_precision;
+	dst->write_time		= src->write_time;
 
 	memcpy(dst->flags,	src->flags,	sizeof(dst->flags));
 	memcpy(dst->features,	src->features,	sizeof(dst->features));
 	memcpy(dst->compat,	src->compat,	sizeof(dst->compat));
 
 	for (i = 0; i < BCH_SB_FIELD_NR; i++) {
-		if (i == BCH_SB_FIELD_journal)
+		int d;
+
+		if ((1U << i) & BCH_SINGLE_DEVICE_SB_FIELDS)
 			continue;
 
-		src_f = bch2_sb_field_get(src, i);
-		dst_f = bch2_sb_field_get(dst, i);
+		src_f = bch2_sb_field_get_id(src, i);
+		dst_f = bch2_sb_field_get_id(dst, i);
+
+		d = (src_f ? le32_to_cpu(src_f->u64s) : 0) -
+		    (dst_f ? le32_to_cpu(dst_f->u64s) : 0);
+		if (d > 0) {
+			int ret = bch2_sb_realloc(dst_handle,
+					le32_to_cpu(dst_handle->sb->u64s) + d);
+
+			if (ret)
+				return ret;
+
+			dst = dst_handle->sb;
+			dst_f = bch2_sb_field_get_id(dst, i);
+		}
+
 		dst_f = __bch2_sb_field_resize(dst_handle, dst_f,
 				src_f ? le32_to_cpu(src_f->u64s) : 0);
 
 		if (src_f)
 			memcpy(dst_f, src_f, vstruct_bytes(src_f));
 	}
+
+	return 0;
 }
 
 int bch2_sb_to_fs(struct bch_fs *c, struct bch_sb *src)
 {
-	struct bch_sb_field_journal *journal_buckets =
-		bch2_sb_get_journal(src);
-	unsigned journal_u64s = journal_buckets
-		? le32_to_cpu(journal_buckets->field.u64s)
-		: 0;
 	int ret;
 
 	lockdep_assert_held(&c->sb_lock);
 
-	ret = bch2_sb_realloc(&c->disk_sb,
-			      le32_to_cpu(src->u64s) - journal_u64s);
-	if (ret)
-		return ret;
-
-	__copy_super(&c->disk_sb, src);
-
-	ret = bch2_sb_replicas_to_cpu_replicas(c);
-	if (ret)
-		return ret;
-
-	ret = bch2_sb_disk_groups_to_cpu(c);
+	ret =   bch2_sb_realloc(&c->disk_sb, 0) ?:
+		__copy_super(&c->disk_sb, src) ?:
+		bch2_sb_replicas_to_cpu_replicas(c) ?:
+		bch2_sb_disk_groups_to_cpu(c);
 	if (ret)
 		return ret;
 
@@ -447,100 +605,112 @@ int bch2_sb_to_fs(struct bch_fs *c, struct bch_sb *src)
 
 int bch2_sb_from_fs(struct bch_fs *c, struct bch_dev *ca)
 {
-	struct bch_sb *src = c->disk_sb.sb, *dst = ca->disk_sb.sb;
-	struct bch_sb_field_journal *journal_buckets =
-		bch2_sb_get_journal(dst);
-	unsigned journal_u64s = journal_buckets
-		? le32_to_cpu(journal_buckets->field.u64s)
-		: 0;
-	unsigned u64s = le32_to_cpu(src->u64s) + journal_u64s;
-	int ret;
-
-	ret = bch2_sb_realloc(&ca->disk_sb, u64s);
-	if (ret)
-		return ret;
-
-	__copy_super(&ca->disk_sb, src);
-	return 0;
+	return __copy_super(&ca->disk_sb, c->disk_sb.sb);
 }
 
 /* read superblock: */
 
-static const char *read_one_super(struct bch_sb_handle *sb, u64 offset)
+static int read_one_super(struct bch_sb_handle *sb, u64 offset, struct printbuf *err)
 {
-	struct bch_csum csum;
 	size_t bytes;
+	int ret;
 reread:
-	bio_reset(sb->bio);
-	bio_set_dev(sb->bio, sb->bdev);
+	bio_reset(sb->bio, sb->bdev, REQ_OP_READ|REQ_SYNC|REQ_META);
 	sb->bio->bi_iter.bi_sector = offset;
-	bio_set_op_attrs(sb->bio, REQ_OP_READ, REQ_SYNC|REQ_META);
 	bch2_bio_map(sb->bio, sb->sb, sb->buffer_size);
 
-	if (submit_bio_wait(sb->bio))
-		return "IO error";
+	ret = submit_bio_wait(sb->bio);
+	if (ret) {
+		prt_printf(err, "IO error: %i", ret);
+		return ret;
+	}
 
-	if (uuid_le_cmp(sb->sb->magic, BCACHE_MAGIC))
-		return "Not a bcachefs superblock";
+	if (!uuid_equal(&sb->sb->magic, &BCACHE_MAGIC) &&
+	    !uuid_equal(&sb->sb->magic, &BCHFS_MAGIC)) {
+		prt_str(err, "Not a bcachefs superblock (got magic ");
+		pr_uuid(err, sb->sb->magic.b);
+		prt_str(err, ")");
+		return -BCH_ERR_invalid_sb_magic;
+	}
 
-	if (le16_to_cpu(sb->sb->version) <  bcachefs_metadata_version_min ||
-	    le16_to_cpu(sb->sb->version) >= bcachefs_metadata_version_max)
-		return "Unsupported superblock version";
+	ret = bch2_sb_compatible(sb->sb, err);
+	if (ret)
+		return ret;
 
 	bytes = vstruct_bytes(sb->sb);
 
-	if (bytes > 512 << sb->sb->layout.sb_max_size_bits)
-		return "Bad superblock: too big";
+	if (bytes > 512 << sb->sb->layout.sb_max_size_bits) {
+		prt_printf(err, "Invalid superblock: too big (got %zu bytes, layout max %lu)",
+		       bytes, 512UL << sb->sb->layout.sb_max_size_bits);
+		return -BCH_ERR_invalid_sb_too_big;
+	}
 
 	if (bytes > sb->buffer_size) {
-		if (bch2_sb_realloc(sb, le32_to_cpu(sb->sb->u64s)))
-			return "cannot allocate memory";
+		ret = bch2_sb_realloc(sb, le32_to_cpu(sb->sb->u64s));
+		if (ret)
+			return ret;
 		goto reread;
 	}
 
-	if (BCH_SB_CSUM_TYPE(sb->sb) >= BCH_CSUM_NR)
-		return "unknown csum type";
+	enum bch_csum_type csum_type = BCH_SB_CSUM_TYPE(sb->sb);
+	if (csum_type >= BCH_CSUM_NR) {
+		prt_printf(err, "unknown checksum type %llu", BCH_SB_CSUM_TYPE(sb->sb));
+		return -BCH_ERR_invalid_sb_csum_type;
+	}
 
 	/* XXX: verify MACs */
-	csum = csum_vstruct(NULL, BCH_SB_CSUM_TYPE(sb->sb),
-			    null_nonce(), sb->sb);
-
-	if (bch2_crc_cmp(csum, sb->sb->csum))
-		return "bad checksum reading superblock";
+	struct bch_csum csum = csum_vstruct(NULL, csum_type, null_nonce(), sb->sb);
+	if (bch2_crc_cmp(csum, sb->sb->csum)) {
+		bch2_csum_err_msg(err, csum_type, sb->sb->csum, csum);
+		return -BCH_ERR_invalid_sb_csum;
+	}
 
 	sb->seq = le64_to_cpu(sb->sb->seq);
 
-	return NULL;
+	return 0;
 }
 
-int bch2_read_super(const char *path, struct bch_opts *opts,
-		    struct bch_sb_handle *sb)
+static int __bch2_read_super(const char *path, struct bch_opts *opts,
+		    struct bch_sb_handle *sb, bool ignore_notbchfs_msg)
 {
 	u64 offset = opt_get(*opts, sb);
 	struct bch_sb_layout layout;
-	const char *err;
+	struct printbuf err = PRINTBUF;
+	struct printbuf err2 = PRINTBUF;
 	__le64 *i;
 	int ret;
-
-	pr_verbose_init(*opts, "");
-
+#ifndef __KERNEL__
+retry:
+#endif
 	memset(sb, 0, sizeof(*sb));
-	sb->mode	= FMODE_READ;
+	sb->mode	= BLK_OPEN_READ;
 	sb->have_bio	= true;
+	sb->holder	= kmalloc(1, GFP_KERNEL);
+	if (!sb->holder)
+		return -ENOMEM;
+
+	sb->sb_name = kstrdup(path, GFP_KERNEL);
+	if (!sb->sb_name)
+		return -ENOMEM;
+
+#ifndef __KERNEL__
+	if (opt_get(*opts, direct_io) == false)
+		sb->mode |= BLK_OPEN_BUFFERED;
+#endif
 
 	if (!opt_get(*opts, noexcl))
-		sb->mode |= FMODE_EXCL;
+		sb->mode |= BLK_OPEN_EXCL;
 
 	if (!opt_get(*opts, nochanges))
-		sb->mode |= FMODE_WRITE;
+		sb->mode |= BLK_OPEN_WRITE;
 
-	sb->bdev = blkdev_get_by_path(path, sb->mode, sb);
+	sb->bdev = blkdev_get_by_path(path, sb->mode, sb->holder, &bch2_sb_handle_bdev_ops);
 	if (IS_ERR(sb->bdev) &&
 	    PTR_ERR(sb->bdev) == -EACCES &&
 	    opt_get(*opts, read_only)) {
-		sb->mode &= ~FMODE_WRITE;
+		sb->mode &= ~BLK_OPEN_WRITE;
 
-		sb->bdev = blkdev_get_by_path(path, sb->mode, sb);
+		sb->bdev = blkdev_get_by_path(path, sb->mode, sb->holder, &bch2_sb_handle_bdev_ops);
 		if (!IS_ERR(sb->bdev))
 			opt_set(*opts, nochanges, true);
 	}
@@ -550,47 +720,56 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 		goto out;
 	}
 
-	err = "cannot allocate memory";
 	ret = bch2_sb_realloc(sb, 0);
-	if (ret)
+	if (ret) {
+		prt_printf(&err, "error allocating memory for superblock");
 		goto err;
+	}
 
-	ret = -EFAULT;
-	err = "dynamic fault";
-	if (bch2_fs_init_fault("read_super"))
+	if (bch2_fs_init_fault("read_super")) {
+		prt_printf(&err, "dynamic fault");
+		ret = -EFAULT;
 		goto err;
+	}
 
-	ret = -EINVAL;
-	err = read_one_super(sb, offset);
-	if (!err)
+	ret = read_one_super(sb, offset, &err);
+	if (!ret)
 		goto got_super;
 
 	if (opt_defined(*opts, sb))
 		goto err;
 
-	pr_err("error reading default superblock: %s", err);
+	prt_printf(&err2, "bcachefs (%s): error reading default superblock: %s\n",
+	       path, err.buf);
+	if (ret == -BCH_ERR_invalid_sb_magic && ignore_notbchfs_msg)
+		printk(KERN_INFO "%s", err2.buf);
+	else
+		printk(KERN_ERR "%s", err2.buf);
+
+	printbuf_exit(&err2);
+	printbuf_reset(&err);
 
 	/*
 	 * Error reading primary superblock - read location of backup
 	 * superblocks:
 	 */
-	bio_reset(sb->bio);
-	bio_set_dev(sb->bio, sb->bdev);
+	bio_reset(sb->bio, sb->bdev, REQ_OP_READ|REQ_SYNC|REQ_META);
 	sb->bio->bi_iter.bi_sector = BCH_SB_LAYOUT_SECTOR;
-	bio_set_op_attrs(sb->bio, REQ_OP_READ, REQ_SYNC|REQ_META);
 	/*
 	 * use sb buffer to read layout, since sb buffer is page aligned but
 	 * layout won't be:
 	 */
 	bch2_bio_map(sb->bio, sb->sb, sizeof(struct bch_sb_layout));
 
-	err = "IO error";
-	if (submit_bio_wait(sb->bio))
+	ret = submit_bio_wait(sb->bio);
+	if (ret) {
+		prt_printf(&err, "IO error: %i", ret);
 		goto err;
+	}
 
 	memcpy(&layout, sb->sb, sizeof(layout));
-	err = validate_sb_layout(&layout);
-	if (err)
+	ret = validate_sb_layout(&layout, &err);
+	if (ret)
 		goto err;
 
 	for (i = layout.sb_offset;
@@ -600,32 +779,63 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 		if (offset == opt_get(*opts, sb))
 			continue;
 
-		err = read_one_super(sb, offset);
-		if (!err)
+		ret = read_one_super(sb, offset, &err);
+		if (!ret)
 			goto got_super;
 	}
 
-	ret = -EINVAL;
 	goto err;
 
 got_super:
-	err = "Superblock block size smaller than device block size";
-	ret = -EINVAL;
 	if (le16_to_cpu(sb->sb->block_size) << 9 <
-	    bdev_logical_block_size(sb->bdev))
+	    bdev_logical_block_size(sb->bdev) &&
+	    opt_get(*opts, direct_io)) {
+#ifndef __KERNEL__
+		opt_set(*opts, direct_io, false);
+		bch2_free_super(sb);
+		goto retry;
+#endif
+		prt_printf(&err, "block size (%u) smaller than device block size (%u)",
+		       le16_to_cpu(sb->sb->block_size) << 9,
+		       bdev_logical_block_size(sb->bdev));
+		ret = -BCH_ERR_block_size_too_small;
 		goto err;
+	}
 
 	ret = 0;
 	sb->have_layout = true;
+
+	ret = bch2_sb_validate(sb, &err, READ);
+	if (ret) {
+		printk(KERN_ERR "bcachefs (%s): error validating superblock: %s\n",
+		       path, err.buf);
+		goto err_no_print;
+	}
 out:
-	pr_verbose_init(*opts, "ret %i", ret);
+	printbuf_exit(&err);
 	return ret;
 err:
+	printk(KERN_ERR "bcachefs (%s): error reading superblock: %s\n",
+	       path, err.buf);
+err_no_print:
 	bch2_free_super(sb);
-	pr_err("error reading superblock: %s", err);
 	goto out;
 }
 
+int bch2_read_super(const char *path, struct bch_opts *opts,
+		    struct bch_sb_handle *sb)
+{
+	return __bch2_read_super(path, opts, sb, false);
+}
+
+/* provide a silenced version for mount.bcachefs */
+
+int bch2_read_super_silent(const char *path, struct bch_opts *opts,
+		    struct bch_sb_handle *sb)
+{
+	return __bch2_read_super(path, opts, sb, true);
+}
+
 /* write superblock: */
 
 static void write_super_endio(struct bio *bio)
@@ -634,7 +844,12 @@ static void write_super_endio(struct bio *bio)
 
 	/* XXX: return errors directly */
 
-	if (bch2_dev_io_err_on(bio->bi_status, ca, "superblock write error: %s",
+	if (bch2_dev_io_err_on(bio->bi_status, ca,
+			       bio_data_dir(bio)
+			       ? BCH_MEMBER_ERROR_write
+			       : BCH_MEMBER_ERROR_read,
+			       "superblock %s error: %s",
+			       bio_data_dir(bio) ? "write" : "read",
 			       bch2_blk_status_to_str(bio->bi_status)))
 		ca->sb_write_error = 1;
 
@@ -647,12 +862,10 @@ static void read_back_super(struct bch_fs *c, struct bch_dev *ca)
 	struct bch_sb *sb = ca->disk_sb.sb;
 	struct bio *bio = ca->disk_sb.bio;
 
-	bio_reset(bio);
-	bio_set_dev(bio, ca->disk_sb.bdev);
+	bio_reset(bio, ca->disk_sb.bdev, REQ_OP_READ|REQ_SYNC|REQ_META);
 	bio->bi_iter.bi_sector	= le64_to_cpu(sb->layout.sb_offset[0]);
 	bio->bi_end_io		= write_super_endio;
 	bio->bi_private		= ca;
-	bio_set_op_attrs(bio, REQ_OP_READ, REQ_SYNC|REQ_META);
 	bch2_bio_map(bio, ca->sb_read_scratch, PAGE_SIZE);
 
 	this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_sb],
@@ -669,16 +882,14 @@ static void write_one_super(struct bch_fs *c, struct bch_dev *ca, unsigned idx)
 
 	sb->offset = sb->layout.sb_offset[idx];
 
-	SET_BCH_SB_CSUM_TYPE(sb, c->opts.metadata_checksum);
+	SET_BCH_SB_CSUM_TYPE(sb, bch2_csum_opt_to_type(c->opts.metadata_checksum, false));
 	sb->csum = csum_vstruct(c, BCH_SB_CSUM_TYPE(sb),
 				null_nonce(), sb);
 
-	bio_reset(bio);
-	bio_set_dev(bio, ca->disk_sb.bdev);
+	bio_reset(bio, ca->disk_sb.bdev, REQ_OP_WRITE|REQ_SYNC|REQ_META);
 	bio->bi_iter.bi_sector	= le64_to_cpu(sb->offset);
 	bio->bi_end_io		= write_super_endio;
 	bio->bi_private		= ca;
-	bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META);
 	bch2_bio_map(bio, sb,
 		     roundup((size_t) vstruct_bytes(sb),
 			     bdev_logical_block_size(ca->disk_sb.bdev)));
@@ -693,14 +904,15 @@ static void write_one_super(struct bch_fs *c, struct bch_dev *ca, unsigned idx)
 int bch2_write_super(struct bch_fs *c)
 {
 	struct closure *cl = &c->sb_write;
-	struct bch_dev *ca;
-	unsigned i, sb = 0, nr_wrote;
-	const char *err;
+	struct printbuf err = PRINTBUF;
+	unsigned sb = 0, nr_wrote;
 	struct bch_devs_mask sb_written;
 	bool wrote, can_mount_without_written, can_mount_with_written;
 	unsigned degraded_flags = BCH_FORCE_IF_DEGRADED;
 	int ret = 0;
 
+	trace_and_count(c, write_super, c, _RET_IP_);
+
 	if (c->opts.very_degraded)
 		degraded_flags |= BCH_FORCE_IF_LOST;
 
@@ -709,21 +921,40 @@ int bch2_write_super(struct bch_fs *c)
 	closure_init_stack(cl);
 	memset(&sb_written, 0, sizeof(sb_written));
 
+	/* Make sure we're using the new magic numbers: */
+	c->disk_sb.sb->magic = BCHFS_MAGIC;
+	c->disk_sb.sb->layout.magic = BCHFS_MAGIC;
+
 	le64_add_cpu(&c->disk_sb.sb->seq, 1);
 
-	if (test_bit(BCH_FS_ERROR, &c->flags))
+	struct bch_sb_field_members_v2 *mi = bch2_sb_field_get(c->disk_sb.sb, members_v2);
+	for_each_online_member(c, ca)
+		__bch2_members_v2_get_mut(mi, ca->dev_idx)->seq = c->disk_sb.sb->seq;
+	c->disk_sb.sb->write_time = cpu_to_le64(ktime_get_real_seconds());
+
+	if (test_bit(BCH_FS_error, &c->flags))
 		SET_BCH_SB_HAS_ERRORS(c->disk_sb.sb, 1);
+	if (test_bit(BCH_FS_topology_error, &c->flags))
+		SET_BCH_SB_HAS_TOPOLOGY_ERRORS(c->disk_sb.sb, 1);
 
 	SET_BCH_SB_BIG_ENDIAN(c->disk_sb.sb, CPU_BIG_ENDIAN);
 
-	for_each_online_member(ca, c, i)
+	bch2_sb_counters_from_cpu(c);
+	bch2_sb_members_from_cpu(c);
+	bch2_sb_members_cpy_v2_v1(&c->disk_sb);
+	bch2_sb_errors_from_cpu(c);
+	bch2_sb_downgrade_update(c);
+
+	for_each_online_member(c, ca)
 		bch2_sb_from_fs(c, ca);
 
-	for_each_online_member(ca, c, i) {
-		err = bch2_sb_validate(&ca->disk_sb);
-		if (err) {
-			bch2_fs_inconsistent(c, "sb invalid before write: %s", err);
-			ret = -1;
+	for_each_online_member(c, ca) {
+		printbuf_reset(&err);
+
+		ret = bch2_sb_validate(&ca->disk_sb, &err, WRITE);
+		if (ret) {
+			bch2_fs_inconsistent(c, "sb invalid before write: %s", err.buf);
+			percpu_ref_put(&ca->io_ref);
 			goto out;
 		}
 	}
@@ -731,30 +962,62 @@ int bch2_write_super(struct bch_fs *c)
 	if (c->opts.nochanges)
 		goto out;
 
-	for_each_online_member(ca, c, i) {
+	/*
+	 * Defer writing the superblock until filesystem initialization is
+	 * complete - don't write out a partly initialized superblock:
+	 */
+	if (!BCH_SB_INITIALIZED(c->disk_sb.sb))
+		goto out;
+
+	if (le16_to_cpu(c->disk_sb.sb->version) > bcachefs_metadata_version_current) {
+		struct printbuf buf = PRINTBUF;
+		prt_printf(&buf, "attempting to write superblock that wasn't version downgraded (");
+		bch2_version_to_text(&buf, le16_to_cpu(c->disk_sb.sb->version));
+		prt_str(&buf, " > ");
+		bch2_version_to_text(&buf, bcachefs_metadata_version_current);
+		prt_str(&buf, ")");
+		bch2_fs_fatal_error(c, "%s", buf.buf);
+		printbuf_exit(&buf);
+		return -BCH_ERR_sb_not_downgraded;
+	}
+
+	for_each_online_member(c, ca) {
 		__set_bit(ca->dev_idx, sb_written.d);
 		ca->sb_write_error = 0;
 	}
 
-	for_each_online_member(ca, c, i)
+	for_each_online_member(c, ca)
 		read_back_super(c, ca);
 	closure_sync(cl);
 
-	for_each_online_member(ca, c, i) {
-		if (!ca->sb_write_error &&
-		    ca->disk_sb.seq !=
-		    le64_to_cpu(ca->sb_read_scratch->seq)) {
+	for_each_online_member(c, ca) {
+		if (ca->sb_write_error)
+			continue;
+
+		if (le64_to_cpu(ca->sb_read_scratch->seq) < ca->disk_sb.seq) {
+			bch2_fs_fatal_error(c,
+				"Superblock write was silently dropped! (seq %llu expected %llu)",
+				le64_to_cpu(ca->sb_read_scratch->seq),
+				ca->disk_sb.seq);
+			percpu_ref_put(&ca->io_ref);
+			ret = -BCH_ERR_erofs_sb_err;
+			goto out;
+		}
+
+		if (le64_to_cpu(ca->sb_read_scratch->seq) > ca->disk_sb.seq) {
 			bch2_fs_fatal_error(c,
-				"Superblock modified by another process");
+				"Superblock modified by another process (seq %llu expected %llu)",
+				le64_to_cpu(ca->sb_read_scratch->seq),
+				ca->disk_sb.seq);
 			percpu_ref_put(&ca->io_ref);
-			ret = -EROFS;
+			ret = -BCH_ERR_erofs_sb_err;
 			goto out;
 		}
 	}
 
 	do {
 		wrote = false;
-		for_each_online_member(ca, c, i)
+		for_each_online_member(c, ca)
 			if (!ca->sb_write_error &&
 			    sb < ca->disk_sb.sb->layout.nr_superblocks) {
 				write_one_super(c, ca, sb);
@@ -764,7 +1027,7 @@ int bch2_write_super(struct bch_fs *c)
 		sb++;
 	} while (wrote);
 
-	for_each_online_member(ca, c, i) {
+	for_each_online_member(c, ca) {
 		if (ca->sb_write_error)
 			__clear_bit(ca->dev_idx, sb_written.d);
 		else
@@ -776,7 +1039,7 @@ int bch2_write_super(struct bch_fs *c)
 	can_mount_with_written =
 		bch2_have_enough_devs(c, sb_written, degraded_flags, false);
 
-	for (i = 0; i < ARRAY_SIZE(sb_written.d); i++)
+	for (unsigned i = 0; i < ARRAY_SIZE(sb_written.d); i++)
 		sb_written.d[i] = ~sb_written.d[i];
 
 	can_mount_without_written =
@@ -794,11 +1057,13 @@ int bch2_write_super(struct bch_fs *c)
 				 !can_mount_with_written ||
 				 (can_mount_without_written &&
 				  !can_mount_with_written), c,
-		"Unable to write superblock to sufficient devices"))
+		"Unable to write superblock to sufficient devices (from %ps)",
+		(void *) _RET_IP_))
 		ret = -1;
 out:
 	/* Make new options visible after they're persistent: */
 	bch2_sb_update(c);
+	printbuf_exit(&err);
 	return ret;
 }
 
@@ -813,377 +1078,314 @@ void __bch2_check_set_feature(struct bch_fs *c, unsigned feat)
 	mutex_unlock(&c->sb_lock);
 }
 
-/* BCH_SB_FIELD_journal: */
-
-static int u64_cmp(const void *_l, const void *_r)
+/* Downgrade if superblock is at a higher version than currently supported: */
+bool bch2_check_version_downgrade(struct bch_fs *c)
 {
-	u64 l = *((const u64 *) _l), r = *((const u64 *) _r);
+	bool ret = bcachefs_metadata_version_current < c->sb.version;
+
+	lockdep_assert_held(&c->sb_lock);
 
-	return l < r ? -1 : l > r ? 1 : 0;
+	/*
+	 * Downgrade, if superblock is at a higher version than currently
+	 * supported:
+	 *
+	 * c->sb will be checked before we write the superblock, so update it as
+	 * well:
+	 */
+	if (BCH_SB_VERSION_UPGRADE_COMPLETE(c->disk_sb.sb) > bcachefs_metadata_version_current) {
+		SET_BCH_SB_VERSION_UPGRADE_COMPLETE(c->disk_sb.sb, bcachefs_metadata_version_current);
+		c->sb.version_upgrade_complete = bcachefs_metadata_version_current;
+	}
+	if (c->sb.version > bcachefs_metadata_version_current) {
+		c->disk_sb.sb->version = cpu_to_le16(bcachefs_metadata_version_current);
+		c->sb.version = bcachefs_metadata_version_current;
+	}
+	if (c->sb.version_min > bcachefs_metadata_version_current) {
+		c->disk_sb.sb->version_min = cpu_to_le16(bcachefs_metadata_version_current);
+		c->sb.version_min = bcachefs_metadata_version_current;
+	}
+	c->disk_sb.sb->compat[0] &= cpu_to_le64((1ULL << BCH_COMPAT_NR) - 1);
+	return ret;
 }
 
-static const char *bch2_sb_validate_journal(struct bch_sb *sb,
-					    struct bch_sb_field *f)
+void bch2_sb_upgrade(struct bch_fs *c, unsigned new_version)
 {
-	struct bch_sb_field_journal *journal = field_to_type(f, journal);
-	struct bch_member *m = bch2_sb_get_members(sb)->members + sb->dev_idx;
-	const char *err;
-	unsigned nr;
-	unsigned i;
-	u64 *b;
-
-	journal = bch2_sb_get_journal(sb);
-	if (!journal)
-		return NULL;
-
-	nr = bch2_nr_journal_buckets(journal);
-	if (!nr)
-		return NULL;
-
-	b = kmalloc_array(sizeof(u64), nr, GFP_KERNEL);
-	if (!b)
-		return "cannot allocate memory";
-
-	for (i = 0; i < nr; i++)
-		b[i] = le64_to_cpu(journal->buckets[i]);
-
-	sort(b, nr, sizeof(u64), u64_cmp, NULL);
-
-	err = "journal bucket at sector 0";
-	if (!b[0])
-		goto err;
-
-	err = "journal bucket before first bucket";
-	if (m && b[0] < le16_to_cpu(m->first_bucket))
-		goto err;
-
-	err = "journal bucket past end of device";
-	if (m && b[nr - 1] >= le64_to_cpu(m->nbuckets))
-		goto err;
+	lockdep_assert_held(&c->sb_lock);
 
-	err = "duplicate journal buckets";
-	for (i = 0; i + 1 < nr; i++)
-		if (b[i] == b[i + 1])
-			goto err;
+	if (BCH_VERSION_MAJOR(new_version) >
+	    BCH_VERSION_MAJOR(le16_to_cpu(c->disk_sb.sb->version)))
+		bch2_sb_field_resize(&c->disk_sb, downgrade, 0);
 
-	err = NULL;
-err:
-	kfree(b);
-	return err;
+	c->disk_sb.sb->version = cpu_to_le16(new_version);
+	c->disk_sb.sb->features[0] |= cpu_to_le64(BCH_SB_FEATURES_ALL);
 }
 
-static const struct bch_sb_field_ops bch_sb_field_ops_journal = {
-	.validate	= bch2_sb_validate_journal,
-};
-
-/* BCH_SB_FIELD_members: */
-
-static const char *bch2_sb_validate_members(struct bch_sb *sb,
-					    struct bch_sb_field *f)
+static int bch2_sb_ext_validate(struct bch_sb *sb, struct bch_sb_field *f,
+				struct printbuf *err)
 {
-	struct bch_sb_field_members *mi = field_to_type(f, members);
-	struct bch_member *m;
+	if (vstruct_bytes(f) < 88) {
+		prt_printf(err, "field too small (%zu < %u)", vstruct_bytes(f), 88);
+		return -BCH_ERR_invalid_sb_ext;
+	}
 
-	if ((void *) (mi->members + sb->nr_devices) >
-	    vstruct_end(&mi->field))
-		return "Invalid superblock: bad member info";
+	return 0;
+}
 
-	for (m = mi->members;
-	     m < mi->members + sb->nr_devices;
-	     m++) {
-		if (!bch2_member_exists(m))
-			continue;
+static void bch2_sb_ext_to_text(struct printbuf *out, struct bch_sb *sb,
+				struct bch_sb_field *f)
+{
+	struct bch_sb_field_ext *e = field_to_type(f, ext);
 
-		if (le64_to_cpu(m->nbuckets) > LONG_MAX)
-			return "Too many buckets";
+	prt_printf(out, "Recovery passes required:");
+	prt_tab(out);
+	prt_bitflags(out, bch2_recovery_passes,
+		     bch2_recovery_passes_from_stable(le64_to_cpu(e->recovery_passes_required[0])));
+	prt_newline(out);
 
-		if (le64_to_cpu(m->nbuckets) -
-		    le16_to_cpu(m->first_bucket) < BCH_MIN_NR_NBUCKETS)
-			return "Not enough buckets";
+	unsigned long *errors_silent = kmalloc(sizeof(e->errors_silent), GFP_KERNEL);
+	if (errors_silent) {
+		le_bitvector_to_cpu(errors_silent, (void *) e->errors_silent, sizeof(e->errors_silent) * 8);
 
-		if (le16_to_cpu(m->bucket_size) <
-		    le16_to_cpu(sb->block_size))
-			return "bucket size smaller than block size";
+		prt_printf(out, "Errors to silently fix:");
+		prt_tab(out);
+		prt_bitflags_vector(out, bch2_sb_error_strs, errors_silent, sizeof(e->errors_silent) * 8);
+		prt_newline(out);
 
-		if (le16_to_cpu(m->bucket_size) <
-		    BCH_SB_BTREE_NODE_SIZE(sb))
-			return "bucket size smaller than btree node size";
+		kfree(errors_silent);
 	}
-
-	return NULL;
 }
 
-static const struct bch_sb_field_ops bch_sb_field_ops_members = {
-	.validate	= bch2_sb_validate_members,
+static const struct bch_sb_field_ops bch_sb_field_ops_ext = {
+	.validate	= bch2_sb_ext_validate,
+	.to_text	= bch2_sb_ext_to_text,
 };
 
-/* BCH_SB_FIELD_crypt: */
-
-static const char *bch2_sb_validate_crypt(struct bch_sb *sb,
-					  struct bch_sb_field *f)
-{
-	struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
-
-	if (vstruct_bytes(&crypt->field) != sizeof(*crypt))
-		return "invalid field crypt: wrong size";
-
-	if (BCH_CRYPT_KDF_TYPE(crypt))
-		return "invalid field crypt: bad kdf type";
-
-	return NULL;
-}
-
-static const struct bch_sb_field_ops bch_sb_field_ops_crypt = {
-	.validate	= bch2_sb_validate_crypt,
+static const struct bch_sb_field_ops *bch2_sb_field_ops[] = {
+#define x(f, nr)					\
+	[BCH_SB_FIELD_##f] = &bch_sb_field_ops_##f,
+	BCH_SB_FIELDS()
+#undef x
 };
 
-/* BCH_SB_FIELD_clean: */
+static const struct bch_sb_field_ops bch2_sb_field_null_ops;
 
-int bch2_sb_clean_validate(struct bch_fs *c, struct bch_sb_field_clean *clean, int write)
+static const struct bch_sb_field_ops *bch2_sb_field_type_ops(unsigned type)
 {
-	struct jset_entry *entry;
-	int ret;
-
-	for (entry = clean->start;
-	     entry < (struct jset_entry *) vstruct_end(&clean->field);
-	     entry = vstruct_next(entry)) {
-		ret = bch2_journal_entry_validate(c, "superblock", entry,
-						  le16_to_cpu(c->disk_sb.sb->version),
-						  BCH_SB_BIG_ENDIAN(c->disk_sb.sb),
-						  write);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
+	return likely(type < ARRAY_SIZE(bch2_sb_field_ops))
+		? bch2_sb_field_ops[type]
+		: &bch2_sb_field_null_ops;
 }
 
-int bch2_fs_mark_dirty(struct bch_fs *c)
+static int bch2_sb_field_validate(struct bch_sb *sb, struct bch_sb_field *f,
+				  struct printbuf *err)
 {
+	unsigned type = le32_to_cpu(f->type);
+	struct printbuf field_err = PRINTBUF;
+	const struct bch_sb_field_ops *ops = bch2_sb_field_type_ops(type);
 	int ret;
 
-	/*
-	 * Unconditionally write superblock, to verify it hasn't changed before
-	 * we go rw:
-	 */
-
-	mutex_lock(&c->sb_lock);
-	SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
-	c->disk_sb.sb->features[0] |= BCH_SB_FEATURES_ALWAYS;
-	ret = bch2_write_super(c);
-	mutex_unlock(&c->sb_lock);
+	ret = ops->validate ? ops->validate(sb, f, &field_err) : 0;
+	if (ret) {
+		prt_printf(err, "Invalid superblock section %s: %s",
+			   bch2_sb_fields[type], field_err.buf);
+		prt_newline(err);
+		bch2_sb_field_to_text(err, sb, f);
+	}
 
+	printbuf_exit(&field_err);
 	return ret;
 }
 
-static struct jset_entry *jset_entry_init(struct jset_entry **end, size_t size)
+void __bch2_sb_field_to_text(struct printbuf *out, struct bch_sb *sb,
+			     struct bch_sb_field *f)
 {
-	struct jset_entry *entry = *end;
-	unsigned u64s = DIV_ROUND_UP(size, sizeof(u64));
+	unsigned type = le32_to_cpu(f->type);
+	const struct bch_sb_field_ops *ops = bch2_sb_field_type_ops(type);
 
-	memset(entry, 0, u64s * sizeof(u64));
-	/*
-	 * The u64s field counts from the start of data, ignoring the shared
-	 * fields.
-	 */
-	entry->u64s = u64s - 1;
+	if (!out->nr_tabstops)
+		printbuf_tabstop_push(out, 32);
 
-	*end = vstruct_next(*end);
-	return entry;
+	if (ops->to_text)
+		ops->to_text(out, sb, f);
 }
 
-void bch2_journal_super_entries_add_common(struct bch_fs *c,
-					   struct jset_entry **end,
-					   u64 journal_seq)
+void bch2_sb_field_to_text(struct printbuf *out, struct bch_sb *sb,
+			   struct bch_sb_field *f)
 {
-	struct bch_dev *ca;
-	unsigned i, dev;
-
-	percpu_down_read(&c->mark_lock);
-
-	if (!journal_seq) {
-		for (i = 0; i < ARRAY_SIZE(c->usage); i++)
-			bch2_fs_usage_acc_to_base(c, i);
-	} else {
-		bch2_fs_usage_acc_to_base(c, journal_seq & JOURNAL_BUF_MASK);
-	}
-
-	{
-		struct jset_entry_usage *u =
-			container_of(jset_entry_init(end, sizeof(*u)),
-				     struct jset_entry_usage, entry);
-
-		u->entry.type	= BCH_JSET_ENTRY_usage;
-		u->entry.btree_id = FS_USAGE_INODES;
-		u->v		= cpu_to_le64(c->usage_base->nr_inodes);
-	}
-
-	{
-		struct jset_entry_usage *u =
-			container_of(jset_entry_init(end, sizeof(*u)),
-				     struct jset_entry_usage, entry);
-
-		u->entry.type	= BCH_JSET_ENTRY_usage;
-		u->entry.btree_id = FS_USAGE_KEY_VERSION;
-		u->v		= cpu_to_le64(atomic64_read(&c->key_version));
-	}
-
-	for (i = 0; i < BCH_REPLICAS_MAX; i++) {
-		struct jset_entry_usage *u =
-			container_of(jset_entry_init(end, sizeof(*u)),
-				     struct jset_entry_usage, entry);
-
-		u->entry.type	= BCH_JSET_ENTRY_usage;
-		u->entry.btree_id = FS_USAGE_RESERVED;
-		u->entry.level	= i;
-		u->v		= cpu_to_le64(c->usage_base->persistent_reserved[i]);
-	}
-
-	for (i = 0; i < c->replicas.nr; i++) {
-		struct bch_replicas_entry *e =
-			cpu_replicas_entry(&c->replicas, i);
-		struct jset_entry_data_usage *u =
-			container_of(jset_entry_init(end, sizeof(*u) + e->nr_devs),
-				     struct jset_entry_data_usage, entry);
-
-		u->entry.type	= BCH_JSET_ENTRY_data_usage;
-		u->v		= cpu_to_le64(c->usage_base->replicas[i]);
-		memcpy(&u->r, e, replicas_entry_bytes(e));
-	}
-
-	for_each_member_device(ca, c, dev) {
-		unsigned b = sizeof(struct jset_entry_dev_usage) +
-			sizeof(struct jset_entry_dev_usage_type) * BCH_DATA_NR;
-		struct jset_entry_dev_usage *u =
-			container_of(jset_entry_init(end, b),
-				     struct jset_entry_dev_usage, entry);
-
-		u->entry.type = BCH_JSET_ENTRY_dev_usage;
-		u->dev = cpu_to_le32(dev);
-		u->buckets_ec		= cpu_to_le64(ca->usage_base->buckets_ec);
-		u->buckets_unavailable	= cpu_to_le64(ca->usage_base->buckets_unavailable);
-
-		for (i = 0; i < BCH_DATA_NR; i++) {
-			u->d[i].buckets = cpu_to_le64(ca->usage_base->d[i].buckets);
-			u->d[i].sectors	= cpu_to_le64(ca->usage_base->d[i].sectors);
-			u->d[i].fragmented = cpu_to_le64(ca->usage_base->d[i].fragmented);
-		}
-	}
+	unsigned type = le32_to_cpu(f->type);
 
-	percpu_up_read(&c->mark_lock);
+	if (type < BCH_SB_FIELD_NR)
+		prt_printf(out, "%s", bch2_sb_fields[type]);
+	else
+		prt_printf(out, "(unknown field %u)", type);
 
-	for (i = 0; i < 2; i++) {
-		struct jset_entry_clock *clock =
-			container_of(jset_entry_init(end, sizeof(*clock)),
-				     struct jset_entry_clock, entry);
+	prt_printf(out, " (size %zu):", vstruct_bytes(f));
+	prt_newline(out);
 
-		clock->entry.type = BCH_JSET_ENTRY_clock;
-		clock->rw	= i;
-		clock->time	= atomic64_read(&c->io_clock[i].now);
-	}
+	__bch2_sb_field_to_text(out, sb, f);
 }
 
-void bch2_fs_mark_clean(struct bch_fs *c)
+void bch2_sb_layout_to_text(struct printbuf *out, struct bch_sb_layout *l)
 {
-	struct bch_sb_field_clean *sb_clean;
-	struct jset_entry *entry;
-	unsigned u64s;
-	int ret;
-
-	mutex_lock(&c->sb_lock);
-	if (BCH_SB_CLEAN(c->disk_sb.sb))
-		goto out;
-
-	SET_BCH_SB_CLEAN(c->disk_sb.sb, true);
-
-	c->disk_sb.sb->compat[0] |= 1ULL << BCH_COMPAT_alloc_info;
-	c->disk_sb.sb->compat[0] |= 1ULL << BCH_COMPAT_alloc_metadata;
-	c->disk_sb.sb->features[0] &= ~(1ULL << BCH_FEATURE_extents_above_btree_updates);
-	c->disk_sb.sb->features[0] &= ~(1ULL << BCH_FEATURE_btree_updates_journalled);
-
-	u64s = sizeof(*sb_clean) / sizeof(u64) + c->journal.entry_u64s_reserved;
-
-	sb_clean = bch2_sb_resize_clean(&c->disk_sb, u64s);
-	if (!sb_clean) {
-		bch_err(c, "error resizing superblock while setting filesystem clean");
-		goto out;
-	}
-
-	sb_clean->flags		= 0;
-	sb_clean->journal_seq	= cpu_to_le64(journal_cur_seq(&c->journal) - 1);
+	unsigned i;
 
-	/* Trying to catch outstanding bug: */
-	BUG_ON(le64_to_cpu(sb_clean->journal_seq) > S64_MAX);
+	prt_printf(out, "Type:                    %u", l->layout_type);
+	prt_newline(out);
 
-	entry = sb_clean->start;
-	bch2_journal_super_entries_add_common(c, &entry, 0);
-	entry = bch2_btree_roots_to_journal_entries(c, entry, entry);
-	BUG_ON((void *) entry > vstruct_end(&sb_clean->field));
+	prt_str(out, "Superblock max size:     ");
+	prt_units_u64(out, 512 << l->sb_max_size_bits);
+	prt_newline(out);
 
-	memset(entry, 0,
-	       vstruct_end(&sb_clean->field) - (void *) entry);
+	prt_printf(out, "Nr superblocks:          %u", l->nr_superblocks);
+	prt_newline(out);
 
-	/*
-	 * this should be in the write path, and we should be validating every
-	 * superblock section:
-	 */
-	ret = bch2_sb_clean_validate(c, sb_clean, WRITE);
-	if (ret) {
-		bch_err(c, "error writing marking filesystem clean: validate error");
-		goto out;
+	prt_str(out, "Offsets:                 ");
+	for (i = 0; i < l->nr_superblocks; i++) {
+		if (i)
+			prt_str(out, ", ");
+		prt_printf(out, "%llu", le64_to_cpu(l->sb_offset[i]));
 	}
-
-	bch2_write_super(c);
-out:
-	mutex_unlock(&c->sb_lock);
+	prt_newline(out);
 }
 
-static const char *bch2_sb_validate_clean(struct bch_sb *sb,
-					  struct bch_sb_field *f)
+void bch2_sb_to_text(struct printbuf *out, struct bch_sb *sb,
+		     bool print_layout, unsigned fields)
 {
-	struct bch_sb_field_clean *clean = field_to_type(f, clean);
-
-	if (vstruct_bytes(&clean->field) < sizeof(*clean))
-		return "invalid field crypt: wrong size";
-
-	return NULL;
-}
-
-static const struct bch_sb_field_ops bch_sb_field_ops_clean = {
-	.validate	= bch2_sb_validate_clean,
-};
-
-static const struct bch_sb_field_ops *bch2_sb_field_ops[] = {
-#define x(f, nr)					\
-	[BCH_SB_FIELD_##f] = &bch_sb_field_ops_##f,
-	BCH_SB_FIELDS()
-#undef x
-};
+	u64 fields_have = 0;
+	unsigned nr_devices = 0;
+
+	if (!out->nr_tabstops)
+		printbuf_tabstop_push(out, 44);
+
+	for (int i = 0; i < sb->nr_devices; i++)
+		nr_devices += bch2_dev_exists(sb, i);
+
+	prt_printf(out, "External UUID:");
+	prt_tab(out);
+	pr_uuid(out, sb->user_uuid.b);
+	prt_newline(out);
+
+	prt_printf(out, "Internal UUID:");
+	prt_tab(out);
+	pr_uuid(out, sb->uuid.b);
+	prt_newline(out);
+
+	prt_printf(out, "Magic number:");
+	prt_tab(out);
+	pr_uuid(out, sb->magic.b);
+	prt_newline(out);
+
+	prt_str(out, "Device index:");
+	prt_tab(out);
+	prt_printf(out, "%u", sb->dev_idx);
+	prt_newline(out);
+
+	prt_str(out, "Label:");
+	prt_tab(out);
+	prt_printf(out, "%.*s", (int) sizeof(sb->label), sb->label);
+	prt_newline(out);
+
+	prt_str(out, "Version:");
+	prt_tab(out);
+	bch2_version_to_text(out, le16_to_cpu(sb->version));
+	prt_newline(out);
+
+	prt_str(out, "Version upgrade complete:");
+	prt_tab(out);
+	bch2_version_to_text(out, BCH_SB_VERSION_UPGRADE_COMPLETE(sb));
+	prt_newline(out);
+
+	prt_printf(out, "Oldest version on disk:");
+	prt_tab(out);
+	bch2_version_to_text(out, le16_to_cpu(sb->version_min));
+	prt_newline(out);
+
+	prt_printf(out, "Created:");
+	prt_tab(out);
+	if (sb->time_base_lo)
+		bch2_prt_datetime(out, div_u64(le64_to_cpu(sb->time_base_lo), NSEC_PER_SEC));
+	else
+		prt_printf(out, "(not set)");
+	prt_newline(out);
+
+	prt_printf(out, "Sequence number:");
+	prt_tab(out);
+	prt_printf(out, "%llu", le64_to_cpu(sb->seq));
+	prt_newline(out);
+
+	prt_printf(out, "Time of last write:");
+	prt_tab(out);
+	bch2_prt_datetime(out, le64_to_cpu(sb->write_time));
+	prt_newline(out);
+
+	prt_printf(out, "Superblock size:");
+	prt_tab(out);
+	prt_printf(out, "%zu", vstruct_bytes(sb));
+	prt_newline(out);
+
+	prt_printf(out, "Clean:");
+	prt_tab(out);
+	prt_printf(out, "%llu", BCH_SB_CLEAN(sb));
+	prt_newline(out);
+
+	prt_printf(out, "Devices:");
+	prt_tab(out);
+	prt_printf(out, "%u", nr_devices);
+	prt_newline(out);
+
+	prt_printf(out, "Sections:");
+	vstruct_for_each(sb, f)
+		fields_have |= 1 << le32_to_cpu(f->type);
+	prt_tab(out);
+	prt_bitflags(out, bch2_sb_fields, fields_have);
+	prt_newline(out);
+
+	prt_printf(out, "Features:");
+	prt_tab(out);
+	prt_bitflags(out, bch2_sb_features, le64_to_cpu(sb->features[0]));
+	prt_newline(out);
+
+	prt_printf(out, "Compat features:");
+	prt_tab(out);
+	prt_bitflags(out, bch2_sb_compat, le64_to_cpu(sb->compat[0]));
+	prt_newline(out);
+
+	prt_newline(out);
+	prt_printf(out, "Options:");
+	prt_newline(out);
+	printbuf_indent_add(out, 2);
+	{
+		enum bch_opt_id id;
 
-static const char *bch2_sb_field_validate(struct bch_sb *sb,
-					  struct bch_sb_field *f)
-{
-	unsigned type = le32_to_cpu(f->type);
+		for (id = 0; id < bch2_opts_nr; id++) {
+			const struct bch_option *opt = bch2_opt_table + id;
 
-	return type < BCH_SB_FIELD_NR
-		? bch2_sb_field_ops[type]->validate(sb, f)
-		: NULL;
-}
+			if (opt->get_sb != BCH2_NO_SB_OPT) {
+				u64 v = bch2_opt_from_sb(sb, id);
 
-void bch2_sb_field_to_text(struct printbuf *out, struct bch_sb *sb,
-			   struct bch_sb_field *f)
-{
-	unsigned type = le32_to_cpu(f->type);
-	const struct bch_sb_field_ops *ops = type < BCH_SB_FIELD_NR
-		? bch2_sb_field_ops[type] : NULL;
+				prt_printf(out, "%s:", opt->attr.name);
+				prt_tab(out);
+				bch2_opt_to_text(out, NULL, sb, opt, v,
+						 OPT_HUMAN_READABLE|OPT_SHOW_FULL_LIST);
+				prt_newline(out);
+			}
+		}
+	}
 
-	if (ops)
-		pr_buf(out, "%s", bch2_sb_fields[type]);
-	else
-		pr_buf(out, "(unknown field %u)", type);
+	printbuf_indent_sub(out, 2);
 
-	pr_buf(out, " (size %llu):", vstruct_bytes(f));
+	if (print_layout) {
+		prt_newline(out);
+		prt_printf(out, "layout:");
+		prt_newline(out);
+		printbuf_indent_add(out, 2);
+		bch2_sb_layout_to_text(out, &sb->layout);
+		printbuf_indent_sub(out, 2);
+	}
 
-	if (ops && ops->to_text)
-		bch2_sb_field_ops[type]->to_text(out, sb, f);
+	vstruct_for_each(sb, f)
+		if (fields & (1 << le32_to_cpu(f->type))) {
+			prt_newline(out);
+			bch2_sb_field_to_text(out, sb, f);
+		}
 }