The target system is CentOS 6.x, but resizing operations will be performed in the pre-centos section of Centos 7.6 kickstart.
I have already run
resize2fs -M / dev / map / centos-home with success.
If I turn up the volume, df says it's 100% full. It's good.
Now I have to reduce the size of the logical volume to match the size of the ext4 file system. I do not want to use rough estimates. I do not need to keep all possible measures either. In a range> = 1 GB, that's fine. that is, the volume can be reduced to 1 GB> = size of the file system.
Target volume Is contain data that I can not lose. I do not have shell (or other) access to the system. The system does not have a CentOS repository, so I can not upgrade it. I do not even have my hands at a distance, I can talk. I use another computer to build and test my installation ISO.
My syntax / script% pre must safely reduce / dev / map / centos-home to be able to create a new root volume for CentOS 7.6 installation. Yes, this whole proposal is crazy.