diff --git a/.bcachefs_revision b/.bcachefs_revision
index 9b6ed538..6b238443 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-aa540d47abe2c4ab53fcf2a6d118dfda13800b56
+f9d2e809a8c3b3a3c6bb0f8fe8e646425f7fce8d
diff --git a/libbcachefs.c b/libbcachefs.c
index ed4f65f2..16f15a8d 100644
--- a/libbcachefs.c
+++ b/libbcachefs.c
@@ -211,9 +211,6 @@ struct bch_sb *bch2_format(struct bch_opt_strs	fs_opt_strs,
 		__bch2_opt_set_sb(sb.sb, &bch2_opt_table[opt_id], v);
 	}
 
-	SET_BCH_SB_ENCODED_EXTENT_MAX_BITS(sb.sb,
-				ilog2(opts.encoded_extent_max));
-
 	struct timespec now;
 	if (clock_gettime(CLOCK_REALTIME, &now))
 		die("error getting current time: %m");
diff --git a/libbcachefs.h b/libbcachefs.h
index b5f9673f..ef90bf2e 100644
--- a/libbcachefs.h
+++ b/libbcachefs.h
@@ -35,7 +35,6 @@ struct format_opts {
 	uuid_le		uuid;
 	unsigned	version;
 	unsigned	superblock_size;
-	unsigned	encoded_extent_max;
 	bool		encrypted;
 	char		*passphrase;
 };
@@ -45,7 +44,6 @@ static inline struct format_opts format_opts_default()
 	return (struct format_opts) {
 		.version		= bcachefs_metadata_version_current,
 		.superblock_size	= SUPERBLOCK_SIZE_DEFAULT,
-		.encoded_extent_max	= 128,
 	};
 }
 
diff --git a/libbcachefs/bcachefs.h b/libbcachefs/bcachefs.h
index 02074a7f..943487f2 100644
--- a/libbcachefs/bcachefs.h
+++ b/libbcachefs/bcachefs.h
@@ -634,7 +634,6 @@ struct bch_fs {
 
 		u16		version;
 		u16		version_min;
-		u16		encoded_extent_max;
 
 		u8		nr_devices;
 		u8		clean;
diff --git a/libbcachefs/compress.c b/libbcachefs/compress.c
index fd7885dc..8e4179d8 100644
--- a/libbcachefs/compress.c
+++ b/libbcachefs/compress.c
@@ -26,7 +26,7 @@ static struct bbuf __bounce_alloc(struct bch_fs *c, unsigned size, int rw)
 {
 	void *b;
 
-	BUG_ON(size > c->sb.encoded_extent_max << 9);
+	BUG_ON(size > c->opts.encoded_extent_max);
 
 	b = kmalloc(size, GFP_NOIO|__GFP_NOWARN);
 	if (b)
@@ -68,7 +68,7 @@ static struct bbuf __bio_map_or_bounce(struct bch_fs *c, struct bio *bio,
 	struct page **pages = NULL;
 	void *data;
 
-	BUG_ON(bvec_iter_sectors(start) > c->sb.encoded_extent_max);
+	BUG_ON(start.bi_size > c->opts.encoded_extent_max);
 
 	if (!PageHighMem(bio_iter_page(bio, start)) &&
 	    bio_phys_contig(bio, start))
@@ -231,8 +231,8 @@ int bch2_bio_uncompress_inplace(struct bch_fs *c, struct bio *bio,
 	BUG_ON(!bio->bi_vcnt);
 	BUG_ON(DIV_ROUND_UP(crc->live_size, PAGE_SECTORS) > bio->bi_max_vecs);
 
-	if (crc->uncompressed_size	> c->sb.encoded_extent_max ||
-	    crc->compressed_size	> c->sb.encoded_extent_max) {
+	if (crc->uncompressed_size << 9	> c->opts.encoded_extent_max ||
+	    crc->compressed_size << 9	> c->opts.encoded_extent_max) {
 		bch_err(c, "error rewriting existing data: extent too big");
 		return -EIO;
 	}
@@ -272,8 +272,8 @@ int bch2_bio_uncompress(struct bch_fs *c, struct bio *src,
 	size_t dst_len = crc.uncompressed_size << 9;
 	int ret = -ENOMEM;
 
-	if (crc.uncompressed_size	> c->sb.encoded_extent_max ||
-	    crc.compressed_size		> c->sb.encoded_extent_max)
+	if (crc.uncompressed_size << 9	> c->opts.encoded_extent_max ||
+	    crc.compressed_size << 9	> c->opts.encoded_extent_max)
 		return -EIO;
 
 	dst_data = dst_len == dst_iter.bi_size
@@ -466,7 +466,7 @@ unsigned bch2_bio_compress(struct bch_fs *c,
 
 	/* Don't consume more than BCH_ENCODED_EXTENT_MAX from @src: */
 	src->bi_iter.bi_size = min_t(unsigned, src->bi_iter.bi_size,
-				     c->sb.encoded_extent_max << 9);
+				     c->opts.encoded_extent_max);
 	/* Don't generate a bigger output than input: */
 	dst->bi_iter.bi_size = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 
@@ -544,10 +544,9 @@ void bch2_fs_compress_exit(struct bch_fs *c)
 
 static int __bch2_fs_compress_init(struct bch_fs *c, u64 features)
 {
-	size_t max_extent = c->sb.encoded_extent_max << 9;
 	size_t decompress_workspace_size = 0;
 	bool decompress_workspace_needed;
-	ZSTD_parameters params = ZSTD_getParams(0, max_extent, 0);
+	ZSTD_parameters params = ZSTD_getParams(0, c->opts.encoded_extent_max, 0);
 	struct {
 		unsigned	feature;
 		unsigned	type;
@@ -579,14 +578,14 @@ have_compressed:
 
 	if (!mempool_initialized(&c->compression_bounce[READ])) {
 		ret = mempool_init_kvpmalloc_pool(&c->compression_bounce[READ],
-						  1, max_extent);
+						  1, c->opts.encoded_extent_max);
 		if (ret)
 			goto out;
 	}
 
 	if (!mempool_initialized(&c->compression_bounce[WRITE])) {
 		ret = mempool_init_kvpmalloc_pool(&c->compression_bounce[WRITE],
-						  1, max_extent);
+						  1, c->opts.encoded_extent_max);
 		if (ret)
 			goto out;
 	}
diff --git a/libbcachefs/ec.c b/libbcachefs/ec.c
index 033ded88..7d78672d 100644
--- a/libbcachefs/ec.c
+++ b/libbcachefs/ec.c
@@ -1152,7 +1152,7 @@ static void ec_stripe_key_init(struct bch_fs *c,
 	s->v.algorithm			= 0;
 	s->v.nr_blocks			= nr_data + nr_parity;
 	s->v.nr_redundant		= nr_parity;
-	s->v.csum_granularity_bits	= ilog2(c->sb.encoded_extent_max);
+	s->v.csum_granularity_bits	= ilog2(c->opts.encoded_extent_max >> 9);
 	s->v.csum_type			= BCH_CSUM_crc32c;
 	s->v.pad			= 0;
 
diff --git a/libbcachefs/extents.c b/libbcachefs/extents.c
index 145b3868..44c584e9 100644
--- a/libbcachefs/extents.c
+++ b/libbcachefs/extents.c
@@ -303,7 +303,7 @@ bool bch2_extent_merge(struct bch_fs *c, struct bkey_s l, struct bkey_s_c r)
 
 			if (lp.crc.csum_type &&
 			    lp.crc.uncompressed_size +
-			    rp.crc.uncompressed_size > c->sb.encoded_extent_max)
+			    rp.crc.uncompressed_size > (c->opts.encoded_extent_max >> 9))
 				return false;
 
 			if (lp.crc.uncompressed_size + rp.crc.uncompressed_size >
diff --git a/libbcachefs/io.c b/libbcachefs/io.c
index 6e64a04d..1b954dff 100644
--- a/libbcachefs/io.c
+++ b/libbcachefs/io.c
@@ -738,7 +738,7 @@ static struct bio *bch2_write_bio_alloc(struct bch_fs *c,
 	 */
 	bch2_bio_alloc_pages_pool(c, bio,
 				  min_t(unsigned, output_available,
-					c->sb.encoded_extent_max << 9));
+					c->opts.encoded_extent_max));
 
 	if (bio->bi_iter.bi_size < output_available)
 		*page_alloc_failed =
@@ -935,8 +935,8 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 		size_t dst_len, src_len;
 
 		if (page_alloc_failed &&
-		    bio_sectors(dst) < wp->sectors_free &&
-		    bio_sectors(dst) < c->sb.encoded_extent_max)
+		    dst->bi_iter.bi_size  < (wp->sectors_free << 9) &&
+		    dst->bi_iter.bi_size < c->opts.encoded_extent_max)
 			break;
 
 		BUG_ON(op->compression_type &&
@@ -956,7 +956,7 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 
 			if (op->csum_type)
 				dst_len = min_t(unsigned, dst_len,
-						c->sb.encoded_extent_max << 9);
+						c->opts.encoded_extent_max);
 
 			if (bounce) {
 				swap(dst->bi_iter.bi_size, dst_len);
@@ -2365,9 +2365,9 @@ int bch2_fs_io_init(struct bch_fs *c)
 			BIOSET_NEED_BVECS) ||
 	    mempool_init_page_pool(&c->bio_bounce_pages,
 				   max_t(unsigned,
-					 btree_sectors(c),
-					 c->sb.encoded_extent_max) /
-				   PAGE_SECTORS, 0) ||
+					 c->opts.btree_node_size,
+					 c->opts.encoded_extent_max) /
+				   PAGE_SIZE, 0) ||
 	    rhashtable_init(&c->promote_table, &bch_promote_params))
 		return -ENOMEM;
 
diff --git a/libbcachefs/opts.h b/libbcachefs/opts.h
index 60fe0301..aadd3958 100644
--- a/libbcachefs/opts.h
+++ b/libbcachefs/opts.h
@@ -127,6 +127,12 @@ enum opt_type {
 	  OPT_UINT(1, BCH_REPLICAS_MAX),				\
 	  BCH_SB_DATA_REPLICAS_REQ,	1,				\
 	  "#",		NULL)						\
+	x(encoded_extent_max,		u32,				\
+	  OPT_FS|OPT_FORMAT|						\
+	  OPT_HUMAN_READABLE|OPT_MUST_BE_POW_2|OPT_SB_FIELD_SECTORS|OPT_SB_FIELD_ILOG2,\
+	  OPT_UINT(4096, 2U << 20),					\
+	  BCH_SB_ENCODED_EXTENT_MAX_BITS, 64 << 10,			\
+	  "size",	"Maximum size of checksummed/compressed extents")\
 	x(metadata_checksum,		u8,				\
 	  OPT_FS|OPT_FORMAT|OPT_MOUNT|OPT_RUNTIME,			\
 	  OPT_STR(bch2_csum_opts),					\
diff --git a/libbcachefs/super-io.c b/libbcachefs/super-io.c
index 3df4c977..b8d2cf66 100644
--- a/libbcachefs/super-io.c
+++ b/libbcachefs/super-io.c
@@ -362,7 +362,6 @@ static void bch2_sb_update(struct bch_fs *c)
 	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.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;