Description of problem:
Boot a windows7 32bit guest with sata backend disk, install and start qemu-ga service, in host, when do "guest-fsfreeze-freeze" to this guest, failed like this:

{"execute":"guest-fsfreeze-freeze" }
{"error": {"desc": "failed to add \\\\?\\Volume{9af402e9-40ee-11e3-b3be-806e6f6e6963}\\ to snapshot set:  (error: 8004230f)"}}

1.Both q35 and pc hit this issue, and virtio-blk has no such issue (virtio-win-prewhql-0.1-72 driver installed).

2.Rhel guest no such issue.

Version-Release number of selected component (if applicable):
# uname -r
3.10.0-37.el7.x86_64
# rpm -q qemu-kvm
qemu-kvm-1.5.3-10.el7.x86_64

windows7 32bit guest, with qemu-ga-win-6.5-4(qemu-ga-x86.msi ) service installed and start
How reproducible:
100%

Steps to Reproduce:
1.Boot a windows7 32bit guest with sata backend:
# /usr/libexec/qemu-kvm -M q35 -cpu SandyBridge -enable-kvm -m 4096 -smp 4,sockets=1,cores=4,threads=1 -name win732 -rtc base=localtime,clock=host,driftfix=slew -drive file=/home/win7x861cp1.qcow2_v3,format=qcow2,if=none,id=drive-ide0-0-0,format=qcow2 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -spice port=5800,disable-ticketing -vga qxl -global qxl-vga.vram_size=67108864 -monitor stdio  -boot menu=on  -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 -device virtio-serial -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0

2.Start qemu-ga service in guest

3.In host, do 
{"execute":"guest-fsfreeze-status"}
{"return": "thawed"}

{"execute":"guest-fsfreeze-freeze" }
Actual results:

{"execute":"guest-fsfreeze-freeze" }
{"error": {"desc": "failed to add \\\\?\\Volume{9af402e9-40ee-11e3-b3be-806e6f6e6963}\\ to snapshot set:  (error: 8004230f)"}}

Expected results:
{"execute":"guest-fsfreeze-freeze" }
{"return": 2}


Additional info:
1.Both q35 and pc hit this issue, and virtio-blk has no such issue (virtio-win-prewhql-0.1-72 driver installed).

2.Rhel guest no such issue.