在centos7使用dumpe2fs，输出可以看到很多group，该如何解读这些输出的信息？

在centos7中，使用dumpe2fs查看指定disk device的时候，可以看到输出很多group，请问该如何解读理解这些输出的信息。

输出的样例如下：

dumpe2fs 1.42.9 (28-Dec-2013)
Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          4b499d76-769a-40a0-93dc-4a31a59add28
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit 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:              2621440
Block count:              10485499
Reserved block count:     440350
Free blocks:              9270338
Free inodes:              2478138
First block:              0
Block size:               4096
:...skipping...
Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          4b499d76-769a-40a0-93dc-4a31a59add28
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit 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:              2621440
Block count:              10485499
Reserved block count:     440350
Free blocks:              9270338
Free inodes:              2478138
First block:              0
Block size:               4096
Fragment size:            4096
Group descriptor size:    64
Reserved GDT blocks:      1019
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Thu Mar  7 14:38:36 2019
Last mount time:          Mon Jul 27 07:49:10 2020
Last write time:          Mon Jul 27 07:49:09 2020
Mount count:              40
Maximum mount count:      -1
Last checked:             Thu Mar  7 14:38:36 2019
Check interval:           0 (<none>)
Lifetime writes:          49 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
First orphan inode:       3501
Default directory hash:   half_md4
Directory Hash Seed:      58cbc593-e8e9-4c19-9dcf-645326b54c80
Journal backup:           inode blocks
Journal features:         journal_incompat_revoke journal_64bit
Journal size:             128M
Journal length:           32768
Journal sequence:         0x0003ba72
Journal start:            30971


Group 0: (Blocks 0-32767) [ITABLE_ZEROED]
  Checksum 0xe26a, unused inodes 0
  Primary superblock at 0, Group descriptors at 1-5
  Reserved GDT blocks at 6-1024
  Block bitmap at 1025 (+1025), Inode bitmap at 1041 (+1041)
  Inode table at 1057-1568 (+1057)
  17792 free blocks, 0 free inodes, 1012 directories
  Free blocks: 10752-11903, 16128-32767
  Free inodes: 
Group 1: (Blocks 32768-65535) [ITABLE_ZEROED]
  Checksum 0x32ef, unused inodes 0
  Backup superblock at 32768, Group descriptors at 32769-32773
  Reserved GDT blocks at 32774-33792
  Block bitmap at 1026 (bg #0 + 1026), Inode bitmap at 1042 (bg #0 + 1042)
  Inode table at 1569-2080 (bg #0 + 1569)
  1 free blocks, 0 free inodes, 317 directories
  Free blocks: 62513
  Free inodes: 
Group 2: (Blocks 65536-98303) [ITABLE_ZEROED]
  Checksum 0x08b6, unused inodes 0
  Block bitmap at 1027 (bg #0 + 1027), Inode bitmap at 1043 (bg #0 + 1043)
  Inode table at 2081-2592 (bg #0 + 2081)
  574 free blocks, 0 free inodes, 18 directories
  Free blocks: 72624-72703, 74720-74751, 75552-75615, 76352-76367, 76375, 76384-76543, 76928-76955, 76958, 76992-77007, 77010, 77012-77019, 77442, 77464-77467, 84707, 9
2427, 92921, 93715, 93758, 93773, 93823, 93832-93835, 93858, 93936-93951, 94144-94187, 96201, 96204-96255, 96544, 97388-97407, 97728-97739, 97744-97747
  Free inodes: 
Group 3: (Blocks 98304-131071) [ITABLE_ZEROED]
  Checksum 0x64e5, unused inodes 1361
  Backup superblock at 98304, Group descriptors at 98305-98309
  Reserved GDT blocks at 98310-99328
  Block bitmap at 1028 (bg #0 + 1028), Inode bitmap at 1044 (bg #0 + 1044)
  Inode table at 2593-3104 (bg #0 + 2593)
  2 free blocks, 1364 free inodes, 1 directories, 1361 unused inodes
  Free blocks: 113605, 114610
  Free inodes: 31405-32768
Group 4: (Blocks 131072-163839) [ITABLE_ZEROED]
  Checksum 0xf29a, unused inodes 8191
  Block bitmap at 1029 (bg #0 + 1029), Inode bitmap at 1045 (bg #0 + 1045)
  Inode table at 3105-3616 (bg #0 + 3105)
  350 free blocks, 8192 free inodes, 0 directories, 8191 unused inodes
  Free blocks: 150806-150847, 151040-151103, 155711, 157120-157247, 157487, 157509, 157558, 157639, 157970, 160589-160674, 162755, 162768-162783, 163262, 163554-163558,
 163791
  Free inodes: 32769-40960