Description of problem:
Restart libvirtd service, try to start a vm with disk image on a nfs share, the following error is seen:
# virsh start test
error: Failed to start domain test
error: internal error Process exited while reading console log output: char device redirected to /dev/pts/3
qemu: could not open disk image /mnt/jialiu/vm1.img: Permission denied


Version-Release number of selected component (if applicable):
libvirt-0.8.1-10.el6.x86_64
# uname -a
Linux dhcp-66-70-86.nay.redhat.com 2.6.32-37.el6.x86_64 #1 SMP Sun Jun 20 19:29:35 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux
qemu-kvm-0.12.1.2-2.81.el6.x86_64
# rpm -qa|grep selinux
selinux-policy-targeted-3.7.19-27.el6.noarch
libselinux-2.0.94-1.el6.x86_64
libselinux-python-2.0.94-1.el6.x86_64
selinux-policy-3.7.19-27.el6.noarch
libselinux-utils-2.0.94-1.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Install a fresh os from nightly build - RHEL6.0-20100622.n.0
2. mount nfs share
# setenforce 0
# getenforce 
Permissive
# iptables -F
# mount 10.66.90.113:/vol/xenimage /mnt (10.66.90.113 is a share nfs)
3. Define a vm, and start it.
# virsh dumpxml test
<domain type='kvm'>
  <name>test</name>
  <uuid>89731ff2-def2-9f1a-0708-5cac6b051fab</uuid>
  <memory>524288</memory>
  <currentMemory>524288</currentMemory>
  <vcpu>1</vcpu>
  <os>
    <type arch='x86_64' machine='rhel6.0.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' cache='none'/>
      <source file='/mnt/jialiu/vm1.img'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' unit='0'/>
    </disk>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <interface type='network'>
      <mac address='52:54:00:29:e3:76'/>
      <source network='default'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes' keymap='en-us'/>
    <video>
      <model type='cirrus' vram='9216' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
  </devices>
</domain>
# virsh start test
Domain test started

# virsh destroy test
Domain test destroyed

4. restart libvirtd, and try to start the vm again:
# service libvirtd restart
Stopping libvirtd daemon:                                  [  OK  ]
Starting libvirtd daemon:                                  [  OK  ]
# virsh start test
error: Failed to start domain test
error: internal error Process exited while reading console log output: char device redirected to /dev/pts/3
qemu: could not open disk image /mnt/jialiu/vm1.img: Permission denied

Actual results:
Fail to start vm, and "Permission denied" is seen.

Expected results:
vm should be started successfully.

Additional info: