[https://bugzilla.redhat.com/show_bug.cgi?id=1463714] In this upstream commit: https://github.com/libguestfs/libguestfs/commit/8a2b0738d1b79f288b14fc352... we accidentally dropped the ~readonly:true flag from the source disk in virt-resize. As a result if you run: virt-resize input output then in some circumstances virt-resize may slightly change the input disk. One particular case is if the input disk contains any filesystems which were not unmounted, then virt-resize would try to correct these filesystems (replaying journals and so on). virt-resize should not touch the input disk so this is a data corruption problem. This was noticed because virt-builder in some situations was displaying an error that previously cached files had their SHA512 checksums changed when that should never occur. This happened because virt-resize was being run with the source file pointing at the cached file, and virt-resize was changing this file. This affects all versions of libguestfs since 1.35.21, so that includes the current stable release (1.36.4), also RHEL 7.4. The fix is: https://github.com/libguestfs/libguestfs/commit/1ca2a8b7ba41d7e4baf1aec5d... You can test if your version of virt-resize is affected by following the reproducer instructions here: https://bugzilla.redhat.com/show_bug.cgi?id=1463714#c2 We're going to release an update to 1.36 this week, and for RHEL 7.4 before 7.4 is shipped. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v