When using a size limited root disk on LXD container instances, changing the size limit caused high I/O utilization, because LXD tried to change the extended file attributes for each and every file in the root disk. This is unnecessary, because you can change the hard limit directly in the quota and the project ID (will maps files to projects) does not change.
My commit has not been merged directly due to problems with Canonicals Contributor License Agreement, but a functional identical commit from the incus project (LXD fork) has been cherry-picked.
Project link: https://github.com/canonical/lxd/pull/13813