Need urgent help with ext4 having different block and fragment size

[anshulmgupta]

Hi,
In ext4 filesystem I see this check https://github.com/sleuthkit/sleuthkit/blob/develop/tsk/fs/ext2fs.c#L3629 which ensures block size and fragments size are same. However if I create the ext4 FS with bigalloc, the fragments size if 64K and the block size if 4K. Then when using the library I am failing on this check, however if I just remove this check everything seems to be working fine. So, I wanted to understand the reason behind this check and also what could be the repercussions if I just remove this check. Thanks!

Please let me know if any further details are needed. Thanks!

tune2fs 1.45.5 (07-Jan-2020)
Filesystem volume name:   <none>
Last mounted on:          <reducted>
Filesystem UUID:          04b4da1d-9096-428a-ab3b-1d95774243b6
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 large_dir sparse_super large_file huge_file dir_nlink extra_isize bigalloc metadata_csum
Filesystem flags:         signed_directory_hash
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              78768
Block count:              1259792
Reserved block count:     62989
Free blocks:              1237024
Free inodes:              78744
First block:              0
Block size:               4096
Cluster size:             65536
Group descriptor size:    64
Reserved GDT blocks:      38
Blocks per group:         524288
Clusters per group:       32768
Inodes per group:         26256
Inode blocks per group:   1641
Flex block group size:    16
Filesystem created:       Mon May 15 19:02:08 2023
Last mount time:          Mon May 15 22:16:23 2023
Last write time:          Mon May 15 22:16:23 2023
Mount count:              2
Maximum mount count:      -1
Last checked:             Mon May 15 19:02:08 2023
Check interval:           0 (<none>)
Lifetime writes:          5325 kB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:	          256
Required extra isize:     32
Desired extra isize:      32
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      f6e47254-112e-4f2e-9436-ff20363614c8
Journal backup:           inode blocks
Checksum type:            crc32c
Checksum:                 0xdd526c9c```

[anshulmgupta]

cc @bcarrier Thanks!