[Pkg-libvirt-maintainers] Bug#748703: libvirt-bin: libvirtd version 1.2.4-3 cannot probe backing volume format

[Bob Weber]

Package: libvirt-bin
Version: 1.2.4-3
Severity: grave
Justification: renders package unusable


After upgrading to 1.2.4-3 libvirtd reports:

kern.log.1:May 17 19:20:06 bob libvirtd[11315]: internal error: cannot probe backing volume format: Debian-7.4-base.img

This happens for every VM that I have that uses a qcow2 backing image file.  A google search only found anything related 
to backing files on a much earlier version of libvirtd.  I have downgraded the libvirt-bin and libvirt0 to 1.2.1-1 to temporarily
resolve the issue.


The script:

for f in *.img ; do
  echo
  echo "=================================="
  qemu-img info $f
done

gives this output:

==================================
image: Debian-7.4-base.img
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 5.3G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false

==================================
image: Debian-7.4.img
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 1.7G
cluster_size: 65536
backing file: Debian-7.4-base.img
Format specific information:
    compat: 1.1
    lazy refcounts: false


-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.12.9-desktop-low-latency-amd64 (SMP w/6 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages libvirt-bin depends on:
ii  adduser              3.113+nmu3
ii  gettext-base         0.18.3.2-1
ii  init-system-helpers  1.18
ii  libapparmor1         2.8.0-5+b1
ii  libaudit1            1:2.3.6-1
ii  libavahi-client3     0.6.31-4
ii  libavahi-common3     0.6.31-4
ii  libblkid1            2.20.1-5.7
ii  libc6                2.18-5
ii  libcap-ng0           0.7.3-1+b1
ii  libdbus-1-3          1.8.2-1
ii  libdevmapper1.02.1   2:1.02.83-2
ii  libfuse2             2.9.3-10
ii  libgcrypt11          1.5.3-4
ii  libgnutls26          2.12.23-15
ii  libnetcf1            1:0.2.3-4
ii  libnl-3-200          3.2.24-2
ii  libnl-route-3-200    3.2.24-2
ii  libnuma1             2.0.9~rc5-1
ii  libparted0debian1    2.3-20
ii  libpcap0.8           1.5.3-2
ii  libpciaccess0        0.13.2-1
ii  librados2            0.72.2-3
ii  librbd1              0.72.2-3
ii  libreadline6         6.3-6
ii  libsasl2-2           2.1.26.dfsg1-9
ii  libselinux1          2.2.2-2
ii  libssh2-1            1.4.3-2
ii  libudev1             204-8
pn  libvirt0             <none>
ii  libxen-4.3           4.3.0-3+b1
ii  libxenstore3.0       4.3.0-3+b1
ii  libxml2              2.9.1+dfsg1-3
ii  libyajl2             2.1.0-1
ii  logrotate            3.8.7-1

Versions of packages libvirt-bin recommends:
ii  bridge-utils    1.5-7
ii  dmidecode       2.12-2
ii  dnsmasq-base    2.69-1
ii  ebtables        2.0.10.4-3
ii  iproute         1:3.14.0-1
ii  iptables        1.4.21-1
ii  libxml2-utils   2.9.1+dfsg1-3
ii  netcat-openbsd  1.105-7
ii  parted          2.3-20
ii  pm-utils        1.4.1-14
ii  qemu            2.0.0+dfsg-4+b1
ii  qemu-kvm        2.0.0+dfsg-4+b1

Versions of packages libvirt-bin suggests:
pn  apparmor     <none>
pn  auditd       <none>
ii  policykit-1  0.105-5
pn  radvd        <none>
ii  systemd      204-8
pn  systemtap    <none>

-- Configuration Files:
/etc/default/libvirt-guests changed:
ON_SHUTDOWN=shutdown
SHUTDOWN_TIMEOUT=60

/etc/libvirt/qemu/networks/default.xml [Errno 2] No such file or directory: u'/etc/libvirt/qemu/networks/default.xml'

-- no debconf information