The main "offending" feature is resize_inode. I spent a while the other day trying to beat support for this feature into libparted, but it's not easy work. I may get there, or I may not ...
One thought I had was that perhaps partman could detect the presence of unsupported features and degrade to using resize2fs instead of libparted. This doesn't offer a progress bar in a way that we can sanely handle in partman, which isn't great, but it would be better than not being able to resize at all.
The main "offending" feature is resize_inode. I spent a while the other day trying to beat support for this feature into libparted, but it's not easy work. I may get there, or I may not ...
One thought I had was that perhaps partman could detect the presence of unsupported features and degrade to using resize2fs instead of libparted. This doesn't offer a progress bar in a way that we can sanely handle in partman, which isn't great, but it would be better than not being able to resize at all.