Okay, let's see. I need to classify this bug report from QEMU into one of the given categories: mistranslation, assembly, other, device, graphic, socket, network, KVM, boot, vnc, debug, files, permissions, performance, kernel, peripherals, hypervisor. The user reported that qemu-img can't create a qcow2 file on an NFS path. The error is "Image is not in qcow2 format." They mentioned it's a known issue in the Red Hat community with bug ID 1817640. Looking at the steps to reproduce, they used qemu-img to create a QCOW2 image on an NFS mount and failed. The strace log shows that pread64 returns empty, causing the error. So, what's happening here? QEMU is trying to write a QCOW2 file but fails when the path is on NFS. The problem seems related to file operations over NFS, maybe permissions or how QEMU handles file creation in network filesystems. The categories given don't include "file system" or "network filesystem." However, "files" is an option. Since it's about creating a file and encountering issues, that might fit under the "files" category. Alternatively, if it's related to permissions, maybe that's another category, but I think "files" is more appropriate here because it's about file creation. So, considering all this, the bug report falls under the "files" category. files