I just tried to increase encrypted LVM partition. The proceduce is: Extend the partition with fdisk -> Resize PV -> Resize LV -> Increase size file system. Detail steps in https://www.thegeekdiary.com/centos-rhel-how-to-extend-physical-volume-in-lvm-by-extending-the-disk-partition-used/. After folowing this steps, I can resize successfull partition.
I found many turtorial about extend encrypted disks, they have to open encrypted volume by luksopen command, then continue with above steps, the example guide in Extend a LUKS encrypted partition to fill disk, so my question is, why they need a step open encrypted volume? without this step, I can extend disk partition? I tried to open encrypted volume, but alway got error
Cannot use device /dev/sda2 which is in use (already mapped or mounted).