id = 986
title = "vpc images are created with bigger virtual size than required"
state = "opened"
created_at = "2022-04-16T12:22:47.018Z"
closed_at = "n/a"
labels = []
url = "https://gitlab.com/qemu-project/qemu/-/issues/986"
host-os = "Debian 11 (and as well Windows)"
host-arch = "x86_64"
qemu-version = "qemu-img version 5.2.0 (Debian 1:5.2+dfsg-11+deb11u1) (and as well self-compiled qemu-img v2.12.1, v6.2.94)"
guest-os = "n/a"
guest-arch = "n/a"
description = """Required virtual size is 895287296, but as qemu-img info reports it is 895426560."""
reproduce = """1. qemu-img create -f vpc img1.vpc 895287296
2. qemu-img info img1.vpc"""
additional = """Converting back and forth is not possible as a result
   ```
$ qemu-img info openSUSE-Leap-15.3-GNOME-Live-x86_64-Media.iso 
image: openSUSE-Leap-15.3-GNOME-Live-x86_64-Media.iso
file format: raw
virtual size: 854 MiB (895287296 bytes)
disk size: 854 MiB

$ qemu-img create -f vpc img1.vpc 895287296
Formatting 'img1.vpc', fmt=vpc size=895287296

$ qemu-img convert -n \\
    -f raw openSUSE-Leap-15.3-GNOME-Live-x86_64-Media.iso \\
    -O vpc img1.vpc
    
$ qemu-img compare \\
    -f raw openSUSE-Leap-15.3-GNOME-Live-x86_64-Media.iso \\
    -F vpc img1.vpc
Warning: Image size mismatch!
Images are identical.

$ qemu-img create -f raw img2.raw 895287296
Formatting 'img2.raw', fmt=raw size=895287296

$ qemu-img convert -n -f vpc img1.vpc -O raw img2.raw
qemu-img: output file is smaller than input file

$ qemu-img compare \\
    -f raw openSUSE-Leap-15.3-GNOME-Live-x86_64-Media.iso \\
    -F raw img2.raw
Content mismatch at offset 0!
   ```"""