I EXT4-formatted a HDD with e2fsprogs 1.45.6-2 on a 64-bit ArchLinux (Kernel 5.4.50) and filled it with data. Afterwards I installed it into a different computer running 32-bit Debian Jessie (Kernel 3.16.84-1) with e2fsprogs 1.42.12-2+deb8u2 and copied a single file to it.
Is this version difference problematic and might have caused damage to the filesystem?
During the shutdown on the 32bit Jessie system I noticed a e2fsck error message, which basically said that it can't run due to metadata_csum.
So I googled and found out that metadata checksums were introduced in 1.43: https://ext4.wiki.kernel.org/index.php/Ext4_Metadata_Checksums
What makes me feel really uncomfortable is the following quote there... It should NOT be possible for old fs code to write to a filesystem with metadata checksums enabled. The metadata_csum flag is implemented as a ROCOMPAT flag, which should keep (non-malicious) old programs from messing things up.
I was expecting to not be able to mount the filesystem at all if there are any incompatibility issues, but I really fear that I might have messed the FS up.
Any help on this would be much appreciated.
Edit:
I used GParted to create the FS and learned in the meantime, that unlike mke2fs it creates filesystems in 32-bit mode by default for drives <16TiB, which is the case for my 8TB drive. I verified this by checking the file systems features provided by tune2fs -l /dev/sda | grep features
, which would otherwise include the term '64bit'.