diff --git a/disk-io.c b/disk-io.c
index 497a6db6..46662c5c 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -607,8 +607,6 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 		ret = btrfs_open_devices(fs_devices, O_RDONLY);
 	BUG_ON(ret);
 
-	ret = btrfs_bootstrap_super_map(&fs_info->mapping_tree, fs_devices);
-	BUG_ON(ret);
 	fs_info->sb_buffer = btrfs_find_create_tree_block(tree_root, sb_bytenr,
 							  4096);
 	BUG_ON(!fs_info->sb_buffer);
@@ -697,6 +695,31 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 	return root;
 }
 
+int write_dev_supers(struct btrfs_root *root, struct extent_buffer *sb,
+		     struct btrfs_device *device)
+{
+	u64 bytenr;
+	u64 flags;
+	int i, ret;
+
+	sb->fd = device->fd;
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		bytenr = btrfs_sb_offset(i);
+		if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
+			break;
+
+		btrfs_set_header_bytenr(sb, bytenr);
+		flags = btrfs_header_flags(sb);
+		btrfs_set_header_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
+		csum_tree_block(root, sb, 0);
+
+		sb->dev_bytenr = bytenr;
+		ret = write_extent_to_disk(sb);
+		BUG_ON(ret);
+	}
+	return 0;
+}
+
 int write_all_supers(struct btrfs_root *root)
 {
 	struct list_head *cur;
@@ -728,11 +751,7 @@ int write_all_supers(struct btrfs_root *root)
 		write_extent_buffer(sb, dev->fs_devices->fsid,
 				    (unsigned long)btrfs_device_fsid(dev_item),
 				    BTRFS_UUID_SIZE);
-		sb->fd = dev->fd;
-		sb->dev_bytenr = sb->start;
-		btrfs_set_header_flag(sb, BTRFS_HEADER_FLAG_WRITTEN);
-		csum_tree_block(root, sb, 0);
-		ret = write_extent_to_disk(sb);
+		ret = write_dev_supers(root, sb, dev);
 		BUG_ON(ret);
 	}
 	return 0;
diff --git a/disk-io.h b/disk-io.h
index 5b827e4f..8e9fab9d 100644
--- a/disk-io.h
+++ b/disk-io.h
@@ -19,9 +19,20 @@
 #ifndef __DISKIO__
 #define __DISKIO__
 
-#define BTRFS_SUPER_INFO_OFFSET (16 * 1024)
+#define BTRFS_SUPER_INFO_OFFSET (64 * 1024)
 #define BTRFS_SUPER_INFO_SIZE 4096
 
+#define BTRFS_SUPER_MIRROR_MAX	 3
+#define BTRFS_SUPER_MIRROR_SHIFT 12
+
+static inline u64 btrfs_sb_offset(int mirror)
+{
+	u64 start = 16 * 1024;
+	if (mirror)
+		return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror);
+	return BTRFS_SUPER_INFO_OFFSET;
+}
+
 struct btrfs_device;
 
 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
diff --git a/extent-tree.c b/extent-tree.c
index 6a5194c5..b4ae95a9 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -61,6 +61,31 @@ void maybe_unlock_mutex(struct btrfs_root *root)
 {
 }
 
+static int remove_sb_from_cache(struct btrfs_root *root,
+				struct btrfs_block_group_cache *cache)
+{
+	u64 bytenr;
+	u64 *logical;
+	int stripe_len;
+	int i, nr, ret;
+	struct extent_io_tree *free_space_cache;
+
+	free_space_cache = &root->fs_info->free_space_cache;
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		bytenr = btrfs_sb_offset(i);
+		ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
+				       cache->key.objectid, bytenr, 0,
+				       &logical, &nr, &stripe_len);
+		BUG_ON(ret);
+		while (nr--) {
+			clear_extent_dirty(free_space_cache, logical[nr],
+				logical[nr] + stripe_len - 1, GFP_NOFS);
+		}
+		kfree(logical);
+	}
+	return 0;
+}
+
 static int cache_block_group(struct btrfs_root *root,
 			     struct btrfs_block_group_cache *block_group)
 {
@@ -153,6 +178,7 @@ next:
 		set_extent_dirty(free_space_cache, last,
 				 last + hole_size - 1, GFP_NOFS);
 	}
+	remove_sb_from_cache(root, block_group);
 	block_group->cached = 1;
 err:
 	btrfs_free_path(path);
diff --git a/mkfs.c b/mkfs.c
index cc0eec02..f942dc73 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -414,8 +414,11 @@ int main(int ac, char **av)
 	if (block_count == 0)
 		block_count = dev_block_count;
 
-	for (i = 0; i < 7; i++)
-		blocks[i] = BTRFS_SUPER_INFO_OFFSET + leafsize * i;
+	blocks[0] = BTRFS_SUPER_INFO_OFFSET;
+	for (i = 1; i < 7; i++) {
+		blocks[i] = BTRFS_SUPER_INFO_OFFSET + 1024 * 1024 +
+			leafsize * i;
+	}
 
 	ret = make_btrfs(fd, file, label, blocks, block_count,
 			 nodesize, leafsize,
diff --git a/utils.c b/utils.c
index 76636893..b6b34ea4 100644
--- a/utils.c
+++ b/utils.c
@@ -194,18 +194,7 @@ int make_btrfs(int fd, const char *device, const char *label,
 
 	/* create the items for the extent tree */
 	nritems = 0;
-	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) -
-		  sizeof(struct btrfs_extent_item);
-	btrfs_set_disk_key_objectid(&disk_key, 0);
-	btrfs_set_disk_key_offset(&disk_key, first_free);
-	btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_ITEM_KEY);
-	btrfs_set_item_key(buf, &disk_key, nritems);
-	btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(buf,  nritems),
-			    sizeof(struct btrfs_extent_item));
-	extent_item = btrfs_item_ptr(buf, nritems, struct btrfs_extent_item);
-	btrfs_set_extent_refs(buf, extent_item, 1);
-	nritems++;
+	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize);
 	for (i = 1; i < 7; i++) {
 		BUG_ON(blocks[i] < first_free);
 		BUG_ON(blocks[i] < blocks[i - 1]);
@@ -517,17 +506,15 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 	kfree(buf);
 	list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
 	device->fs_devices = root->fs_info->fs_devices;
-	ret = btrfs_bootstrap_super_map(&root->fs_info->mapping_tree,
-					root->fs_info->fs_devices);
-	BUG_ON(ret);
 	return 0;
 }
 
 int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret)
 {
 	u64 block_count;
+	u64 bytenr;
 	struct stat st;
-	int ret;
+	int i, ret;
 
 	ret = fstat(fd, &st);
 	if (ret < 0) {
@@ -552,6 +539,13 @@ int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret)
 		exit(1);
 	}
 
+	for (i = 0 ; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		bytenr = btrfs_sb_offset(i);
+		if (bytenr >= block_count)
+			break;
+		zero_blocks(fd, bytenr, BTRFS_SUPER_INFO_SIZE);
+	}
+
 	if (zero_end) {
 		ret = zero_dev_end(fd, block_count);
 		if (ret) {
diff --git a/volumes.c b/volumes.c
index a5519930..c2618479 100644
--- a/volumes.c
+++ b/volumes.c
@@ -888,6 +888,62 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
 	return ret;
 }
 
+int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
+		     u64 chunk_start, u64 physical, u64 devid,
+		     u64 **logical, int *naddrs, int *stripe_len)
+{
+	struct cache_extent *ce;
+	struct map_lookup *map;
+	u64 *buf;
+	u64 bytenr;
+	u64 length;
+	u64 stripe_nr;
+	int i, j, nr = 0;
+
+	ce = find_first_cache_extent(&map_tree->cache_tree, chunk_start);
+	BUG_ON(!ce || ce->start != chunk_start);
+	map = container_of(ce, struct map_lookup, ce);
+
+		length = ce->size;
+	if (map->type & BTRFS_BLOCK_GROUP_RAID10)
+		length = ce->size / (map->num_stripes / map->sub_stripes);
+	else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
+		length = ce->size / map->num_stripes;
+
+	buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
+
+	for (i = 0; i < map->num_stripes; i++) {
+		if (devid && map->stripes[i].dev->devid != devid)
+			continue;
+		if (map->stripes[i].physical > physical ||
+		    map->stripes[i].physical + length <= physical)
+			continue;
+
+		stripe_nr = (physical - map->stripes[i].physical) /
+			    map->stripe_len;
+
+		if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
+			stripe_nr = (stripe_nr * map->num_stripes + i) /
+				    map->sub_stripes;
+		} else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
+			stripe_nr = stripe_nr * map->num_stripes + i;
+		}
+		bytenr = chunk_start + stripe_nr * map->stripe_len;
+		for (j = 0; j < nr; j++) {
+			if (buf[j] == bytenr)
+				break;
+		}
+		if (j == nr)
+			buf[nr++] = bytenr;
+	}
+
+	*logical = buf;
+	*naddrs = nr;
+	*stripe_len = map->stripe_len;
+
+	return 0;
+}
+
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 		    u64 logical, u64 *length,
 		    struct btrfs_multi_bio **multi_ret, int mirror_num)
@@ -1000,7 +1056,6 @@ again:
 	}
 	BUG_ON(stripe_index >= map->num_stripes);
 
-	BUG_ON(stripe_index != 0 && multi->num_stripes > 1);
 	for (i = 0; i < multi->num_stripes; i++) {
 		multi->stripes[i].physical =
 			map->stripes[stripe_index].physical + stripe_offset +
@@ -1118,7 +1173,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 	u64 logical;
 	u64 length;
 	u64 devid;
-	u64 super_offset_diff = 0;
 	u8 uuid[BTRFS_UUID_SIZE];
 	int num_stripes;
 	int ret;
@@ -1127,12 +1181,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 	logical = key->offset;
 	length = btrfs_chunk_length(leaf, chunk);
 
-	if (logical < BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE) {
-		super_offset_diff = BTRFS_SUPER_INFO_OFFSET +
-			BTRFS_SUPER_INFO_SIZE - logical;
-		logical = BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE;
-	}
-
 	ce = find_first_cache_extent(&map_tree->cache_tree, logical);
 
 	/* already mapped? */
@@ -1146,7 +1194,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 		return -ENOMEM;
 
 	map->ce.start = logical;
-	map->ce.size = length - super_offset_diff;
+	map->ce.size = length;
 	map->num_stripes = num_stripes;
 	map->io_width = btrfs_chunk_io_width(leaf, chunk);
 	map->io_align = btrfs_chunk_io_align(leaf, chunk);
@@ -1157,8 +1205,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 
 	for (i = 0; i < num_stripes; i++) {
 		map->stripes[i].physical =
-			btrfs_stripe_offset_nr(leaf, chunk, i) +
-				super_offset_diff;
+			btrfs_stripe_offset_nr(leaf, chunk, i);
 		devid = btrfs_stripe_devid_nr(leaf, chunk, i);
 		read_extent_buffer(leaf, uuid, (unsigned long)
 				   btrfs_stripe_dev_uuid_nr(chunk, i),
diff --git a/volumes.h b/volumes.h
index ad8cfaf3..bb787517 100644
--- a/volumes.h
+++ b/volumes.h
@@ -99,6 +99,9 @@ int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 		    u64 logical, u64 *length,
 		    struct btrfs_multi_bio **multi_ret, int mirror_num);
+int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
+		     u64 chunk_start, u64 physical, u64 devid,
+		     u64 **logical, int *naddrs, int *stripe_len);
 int btrfs_read_sys_array(struct btrfs_root *root);
 int btrfs_read_chunk_tree(struct btrfs_root *root);
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,