[Pkg-libvirt-maintainers] Bug#748703: More info

[Bob Weber]

I re-installed libvirt-bin 1.2.4-3 and libvirt0 1.2.4-3.  The problem persists. 
The following virsh session shows the problem:

virsh # list
 Id    Name                           State
----------------------------------------------------
 2     Weather                        running
 3     Debian-7.4-OpenVPN             running

virsh # vol-list Debian-7.4
 Name                 Path                                   
------------------------------------------------------------------------------
 commit.sh            /home/img/MyMachines/Debian-7.4/commit.sh
 Debian-7.4-base.img  /home/img/MyMachines/Debian-7.4/Debian-7.4-base.img
 Debian-7.4.img       /home/img/MyMachines/Debian-7.4/Debian-7.4.img
 info                 /home/img/MyMachines/Debian-7.4/info   
 mk-baking.sh         /home/img/MyMachines/Debian-7.4/mk-baking.sh
 test.img             /home/img/MyMachines/Debian-7.4/test.img

virsh # vol-info --pool Debian-7.4 Debian-7.4-base.img
Name:           Debian-7.4-base.img
Type:           file
Capacity:       30.00 GiB
Allocation:     5.31 GiB

virsh # vol-info --pool Debian-7.4 Debian-7.4.img
Name:           Debian-7.4.img
error: cannot stat file 'Debian-7.4-base.img': No such file or directory

virsh #

------------------

The Debian-7.4.img file uses  the backing file Debian-7.4-base.img and it exists
at /home/img/MyMachines/Debian-7.4/Debian-7.4-base.img.

The VM runs ok. 

Viewing the details screen of the VM window under Virtual Machine Manager
clicking on the "SATA Disk 1"  gives this error report:

Error refreshing hardware page: cannot stat file 'Debian-7.4-base.img': No such
file or directory

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/details.py", line 1307, in hw_selected
    self.refresh_disk_page()
  File "/usr/share/virt-manager/virtManager/details.py", line 2921, in
refresh_disk_page
    size = vol.get_pretty_capacity()
  File "/usr/share/virt-manager/virtManager/storagevol.py", line 60, in
get_pretty_capacity
    return util.pretty_bytes(self.get_capacity())
  File "/usr/share/virt-manager/virtManager/storagevol.py", line 57, in get_capacity
    return long(util.xpath(self.get_xml(), "/volume/capacity"))
  File "/usr/share/virt-manager/virtManager/libvirtobject.py", line 93, in get_xml
    self.refresh_xml()
  File "/usr/share/virt-manager/virtManager/libvirtobject.py", line 105, in
refresh_xml
    self._xml = self._XMLDesc(self._active_xml_flags)
  File "/usr/share/virt-manager/virtManager/storagevol.py", line 35, in _XMLDesc
    return self.vol.XMLDesc(flags)
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 2985, in XMLDesc
    if ret is None: raise libvirtError ('virStorageVolGetXMLDesc() failed',
vol=self)
libvirtError: cannot stat file 'Debian-7.4-base.img': No such file or directory

--------------------
The following lines in syslog show libvirtd errors for this VM.

May 23 15:48:01 bob libvirtd[1419]: Failed to open file 'Debian-7.4-base.img':
No such file or directory
May 23 15:48:01 bob libvirtd[1419]: internal error: cannot probe backing volume
format: Debian-7.4-base.img
May 23 15:48:01 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:01 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:01 bob libvirtd[1419]: Failed to open file 'Debian-7.4-base.img':
No such file or directory
May 23 15:48:01 bob libvirtd[1419]: internal error: cannot probe backing volume
format: Debian-7.4-base.img
May 23 15:48:01 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:01 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:01 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:02 bob libvirtd[1419]: Failed to open file 'Debian-7.4-base.img':
No such file or directory
May 23 15:48:02 bob libvirtd[1419]: internal error: cannot probe backing volume
format: Debian-7.4-base.img
May 23 15:48:02 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:02 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:02 bob libvirtd[1419]: Failed to open file 'Debian-7.4-base.img':
No such file or directory
May 23 15:48:02 bob libvirtd[1419]: internal error: cannot probe backing volume
format: Debian-7.4-base.img
May 23 15:48:02 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:02 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory
May 23 15:48:02 bob libvirtd[1419]: cannot stat file 'Debian-7.4-base.img': No
such file or directory

I see these same messages for every VM I have that uses backing files.

Attached is a screen capture of the "Connection Details" "Storage" tab under
Virtual Machine manager.  It only shows Debian-7.4-base.img
with Debian-7.4.img missing (even after refresh).

This is the last line for /var/log/libvirt/qemu/Debian-7.4-OpenVPN.log showing
how the VM is opened.

2014-05-23 19:46:53.030+0000: starting up
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
QEMU_AUDIO_DRV=none /usr/bin/kvm -name Debian-7.4-OpenVPN -S -machine
pc-i440fx-1.7,accel=kvm,usb=off -m 2480 -realtime mlock=off -smp 2
,sockets=2,cores=1,threads=1 -uuid 20f0f7e0-92c7-d6fe-bc93-d7f493606bdd
-no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/Debian-7.4-OpenVPN.monitor,server,nowait
-mon chardev
=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot
order=cd,menu=on,strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-device ahci,id=ahci0,bus=pci.0,addr=0x5 -drive file=/home/im
g/MyMachines/Debian-7.4/Debian-7.4.img,if=none,id=drive-sata0-0-0,format=qcow2
-device ide-hd,bus=ahci0.0,drive=drive-sata0-0-0,id=sata0-0-0 -drive
file=/home/iso/debian-7.4.0-i386-netinst.iso,if=none,id=drive-i
de0-1-0,readonly=on,format=raw -device
ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev
tap,fd=23,id=hostnet0,vhost=on,vhostfd=25 -device
virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:40:6e
:24,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -vnc 127.0.0.1:1 -device
cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device
intel-hda,id=sound0,bus=pci.0,addr=0x
4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6
char device redirected to /dev/pts/0 (label charserial0)

---------------------

It looks like libvirt is loosing the path to the backing file when it parses
Debian-7.4.img.  Hope this helps.

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