Let me guess, the server has been running with metadata checksumming (and the mystery feature) disabled since that incident and it still hasn't been switched on again.
0x10000 in the mentioned bitfield
is EXT4_FEATURE_RO_COMPAT_ORPHAN_PRESENT which is documented here: <a href="https://www.kernel.org/doc/Documentation/filesystems/ext4/orphan.rst" rel="nofollow">https://www.kernel.org/doc/Documentation/filesystems/ext4/or...</a><p>If I’m understanding this correctly, probably the only effect of having accidentally turned this off is leaking some blocks.
And people say "just do it on-prem, it's cheaper than cloud! It's not all that hard." Work like this is impressive as hell, but finding wizards who can do this kind of work is difficult and expensive. I've sat there are poured over hexdumps trying to get it to reveal it's secrets (Kaitai is pretty cool). But this kind of nitty gritty went away with cloud, to be replaced with a different kind of problem, distributed systems. My point is, that's pretty cool, but there's less demand for that kind of work these days, which is unfortunate, because I kind of liked it.