fdisk -l

device     Boot   Start     End Sectors  Size Id Type
/dev/sdb1          2048 2099199 2097152    1G 83 Linux
/dev/sdb2       2099200 6293503 4194304    2G 83 Linux
**/dev/sdb3**       6293504 6293903     400  200K 83 Linux

blkid /dev/sdb3

/dev/sdb3: UUID="96cac981-3764-474b-82fe-89efc5ec17be" TYPE="ext4" PARTUUID="81a3aca2-03"

tune2fs /dev/sdb3 -l

tune2fs 1.42.13 (17-May-2015)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          96cac981-3764-474b-82fe-89efc5ec17be
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              32
Block count:              200
Reserved block count:     10
Free blocks:              177
Free inodes:              21
First block:              1
Block size:               1024
Fragment size:            1024
Blocks per group:         8192
Fragments per group:      8192
Inodes per group:         32
Inode blocks per group:   4
Flex block group size:    16
Filesystem created:       Sun Oct 30 20:41:15 2016
Last mount time:          n/a
Last write time:          Sun Oct 30 20:41:15 2016
Mount count:              0
Maximum mount count:      -1
Last checked:             Sun Oct 30 20:41:15 2016
Check interval:           0 (<none>)
Lifetime writes:          90 kB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:              128
Default directory hash:   half_md4
Directory Hash Seed:      83db19a5-4c95-418e-91f1-3acc3de261d9

/dev/sdb3文件系统size为200K，但是（block sum size + inode sum size）1024B*200+128B*32>200K，请问这里怎么解释呢？