Code review comment for ~smoser/curtin:feature/bug-1746348-fsimage-support

The Precise image currently in the stream is a gzip compressed ext4 image. It seems this supports SquashFS files by mounting them and coping the files. Why not support mounting the Precise ext4 image so the streams don't have to be modified to add a SquashFS image?

If Curtin is supporting SquashFS why not use unsquashfs and skip mounting it?