1 files changed, 37 insertions, 7 deletions

diff --git a/fs/btrfs/mkfs.c b/fs/btrfs/mkfs.c
index 9aa900811c33..1cac5ab114dd 100644
--- a/fs/btrfs/mkfs.c
+++ b/fs/btrfs/mkfs.c
@@ -42,7 +42,7 @@ int mkfs(int fd, u64 num_blocks, u32 blocksize)
         btrfs_set_header_parentid(&empty_leaf->header,
                                   BTRFS_ROOT_TREE_OBJECTID);
         btrfs_set_header_blocknr(&empty_leaf->header, start_block + 1);
-        btrfs_set_header_nritems(&empty_leaf->header, 2);
+        btrfs_set_header_nritems(&empty_leaf->header, 3);
 
         /* create the items for the root tree */
         btrfs_set_root_blocknr(&root_item, start_block + 2);
@@ -61,17 +61,25 @@ int mkfs(int fd, u64 num_blocks, u32 blocksize)
         btrfs_set_root_blocknr(&root_item, start_block + 3);
         itemoff = itemoff - sizeof(root_item);
         btrfs_set_item_offset(&item, itemoff);
-        btrfs_set_disk_key_objectid(&item.key, BTRFS_FS_TREE_OBJECTID);
+        btrfs_set_disk_key_objectid(&item.key, BTRFS_INODE_MAP_OBJECTID);
         memcpy(empty_leaf->items + 1, &item, sizeof(item));
         memcpy(btrfs_leaf_data(empty_leaf) + itemoff,
                 &root_item, sizeof(root_item));
+
+        btrfs_set_root_blocknr(&root_item, start_block + 4);
+        itemoff = itemoff - sizeof(root_item);
+        btrfs_set_item_offset(&item, itemoff);
+        btrfs_set_disk_key_objectid(&item.key, BTRFS_FS_TREE_OBJECTID);
+        memcpy(empty_leaf->items + 2, &item, sizeof(item));
+        memcpy(btrfs_leaf_data(empty_leaf) + itemoff,
+                &root_item, sizeof(root_item));
         ret = pwrite(fd, empty_leaf, blocksize, (start_block + 1) * blocksize);
 
         /* create the items for the extent tree */
         btrfs_set_header_parentid(&empty_leaf->header,
                                   BTRFS_EXTENT_TREE_OBJECTID);
         btrfs_set_header_blocknr(&empty_leaf->header, start_block + 2);
-        btrfs_set_header_nritems(&empty_leaf->header, 4);
+        btrfs_set_header_nritems(&empty_leaf->header, 5);
 
         /* item1, reserve blocks 0-16 */
         btrfs_set_disk_key_objectid(&item.key, 0);
@@ -108,12 +116,12 @@ int mkfs(int fd, u64 num_blocks, u32 blocksize)
         memcpy(btrfs_leaf_data(empty_leaf) + btrfs_item_offset(&item),
                 &extent_item, btrfs_item_size(&item));
 
-        /* item4, give block 19 to the FS root */
+        /* item4, give block 19 to the inode map */
         btrfs_set_disk_key_objectid(&item.key, start_block + 3);
         btrfs_set_disk_key_offset(&item.key, 1);
         itemoff = itemoff - sizeof(struct btrfs_extent_item);
         btrfs_set_item_offset(&item, itemoff);
-        btrfs_set_extent_owner(&extent_item, BTRFS_FS_TREE_OBJECTID);
+        btrfs_set_extent_owner(&extent_item, BTRFS_INODE_MAP_OBJECTID);
         memcpy(empty_leaf->items + 3, &item, sizeof(item));
         memcpy(btrfs_leaf_data(empty_leaf) + btrfs_item_offset(&item),
                 &extent_item, btrfs_item_size(&item));
@@ -121,12 +129,34 @@ int mkfs(int fd, u64 num_blocks, u32 blocksize)
         if (ret != blocksize)
                 return -1;
 
-        /* finally create the FS root */
-        btrfs_set_header_parentid(&empty_leaf->header, BTRFS_FS_TREE_OBJECTID);
+        /* item5, give block 20 to the FS root */
+        btrfs_set_disk_key_objectid(&item.key, start_block + 4);
+        btrfs_set_disk_key_offset(&item.key, 1);
+        itemoff = itemoff - sizeof(struct btrfs_extent_item);
+        btrfs_set_item_offset(&item, itemoff);
+        btrfs_set_extent_owner(&extent_item, BTRFS_FS_TREE_OBJECTID);
+        memcpy(empty_leaf->items + 4, &item, sizeof(item));
+        memcpy(btrfs_leaf_data(empty_leaf) + btrfs_item_offset(&item),
+                &extent_item, btrfs_item_size(&item));
+        ret = pwrite(fd, empty_leaf, blocksize, (start_block + 2) * blocksize);
+        if (ret != blocksize)
+                return -1;
+
+        /* create the inode map */
+        btrfs_set_header_parentid(&empty_leaf->header,
+                                  BTRFS_INODE_MAP_OBJECTID);
         btrfs_set_header_blocknr(&empty_leaf->header, start_block + 3);
         btrfs_set_header_nritems(&empty_leaf->header, 0);
         ret = pwrite(fd, empty_leaf, blocksize, (start_block + 3) * blocksize);
         if (ret != blocksize)
                 return -1;
+
+        /* finally create the FS root */
+        btrfs_set_header_parentid(&empty_leaf->header, BTRFS_FS_TREE_OBJECTID);
+        btrfs_set_header_blocknr(&empty_leaf->header, start_block + 4);
+        btrfs_set_header_nritems(&empty_leaf->header, 0);
+        ret = pwrite(fd, empty_leaf, blocksize, (start_block + 4) * blocksize);
+        if (ret != blocksize)
+                return -1;
         return 0;
 }