[lug] Removing Ext4 Attributes: metdata_csum, 64bit

[stimits at comcast.net]

Hi,
 
While working on a multi-boot system and still at a point where it is ok to wipe it out, I am wondering whether anyone here knows how to remove certain ext4 attributes. The multi-boot system has both older and newer flavors of Linux distributions, and it would be very convenient if each system could mount and edit the other system's ext4 partitions.
 
Sadly, newer file systems have added ext4 attributes 64bit and metadata_csum...these are incompatible with older systems, so older systems cannot use these. I can't just ignore the attributes with an option since mount doesn't understand those options (it's somewhat humorous to realize software has to understand a feature to ignore a feature it doesn't understand).
 
I could reformat and pass options to not use those ("mkfs.ext4 -O ^metadata_csum,^64bit"), but what I'm really wondering about is whether there is a way to non-destructively edit those attributes out of an existing file system? tune2fs does not seem to have this ability for those particular attributes. I thought perhaps someone here would know some arcane magic to remove those attributes in a non-destructive way. If not, I'll just reformat and reinstall, but I've spent over a day of work on this already and didn't want to start over if not necessary. I expect to run into this issue again in the future, it isn't just this system.
 
Thanks!
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