Description of problem:
Disk didn't be deleted during the copy operation 

Version-Release number of selected component (if applicable):
host kernel:3.10.0-503.el7.x86_64
qemu-kvm-rhev-2.6.0-23.el7.x86_64
guest: win10.64 

How reproducible:
3/3

Steps to Reproduce:
1.Boot guest 
/usr/libexec/qemu-kvm \
-M pc \
-cpu SandyBridge \
-nodefaults -rtc base=utc \
-m 4G \
-smp 2,sockets=2,cores=1,threads=1 \
-enable-kvm \
-name rhel7.3 \
-uuid 990ea161-6b67-47b2-b803-19fb01d30d12 \
-smbios type=1,manufacturer='Red Hat',product='RHEV Hypervisor',version=el6,serial=koTUXQrb,uuid=feebc8fd-f8b0-4e75-abc3-e63fcdb67170 \
-k en-us \
-nodefaults \
-serial unix:/tmp/serial0,server,nowait \
-boot menu=on \
-bios /usr/share/seabios/bios.bin \
-chardev file,path=/home/pci-bridge/seabios.log,id=seabios \
-device isa-debugcon,chardev=seabios,iobase=0x402 \
-qmp tcp:0:6666,server,nowait \
-device pci-bridge,bus=pci.0,id=bridge0,chassis_nr=1 \
-drive file=/home/pci-bridge/win10-1.qcow2,if=none,id=drive-virtio-disk0,format=qcow2,cache=none,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1,bus=bridge0,addr=0x1 \
-device virtio-net-pci,netdev=tap10,mac=9a:6a:6b:6c:6d:6e,bus=bridge0,addr=0x2 -netdev tap,id=tap10 \
-device VGA,id=video \
-vnc :2 \
-device pci-bridge,bus=pci.0,id=bridge1,chassis_nr=2 \
-device nec-usb-xhci,id=xhci0,bus=bridge1,addr=0x1 \
-drive file=/home/pci-bridge/usb-disk.qcow2,if=none,format=qcow2,id=usbstorage1 \
-device usb-storage,drive=usbstorage1,id=usbdevice,bus=xhci0.0 \
-device pci-bridge,bus=pci.0,id=bridge2,chassis_nr=3 \
-device pci-bridge,bus=pci.0,id=bridge3,chassis_nr=4 \
-device pci-bridge,bus=pci.0,id=bridge4,chassis_nr=5 \
-device pci-bridge,bus=pci.0,id=bridge5,chassis_nr=6 \
-device pci-bridge,bus=pci.0,id=bridge6,chassis_nr=6 \
-device pci-bridge,bus=pci.0,id=bridge7,chassis_nr=7 \
-monitor stdio \
-drive file=/home/virtio-win.iso,if=none,id=ide1,format=raw,media=cdrom \
-device ide-drive,bus=ide.0,unit=0,drive=ide1,id=ide1 \

(qemu) info block
drive-virtio-disk0 (#block137): /home/pci-bridge/win10-1.qcow2 (qcow2)
    Cache mode:       writethrough, direct

usbstorage1 (#block383): /home/pci-bridge/usb-disk.qcow2 (qcow2)
    Cache mode:       writeback

ide1 (#block577): /home/virtio-win.iso (raw, read-only)
    Removable device: not locked, tray closed
    Cache mode:       writeback


2.Hot plug disk through qmp
{"execute":"__com.redhat_drive_add", "arguments": {"file":"/home/pci-bridge/block1.qcow2","format":"qcow2","id":"test1"}}
{"return": {}}
{"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"test1","id":"test1","bus":"bridge3","addr":"0x1"}}
{"return": {}}

(qemu) info block
drive-virtio-disk0 (#block137): /home/pci-bridge/win10-1.qcow2 (qcow2)
    Cache mode:       writeback, direct

usbstorage1 (#block383): /home/pci-bridge/usb-disk.qcow2 (qcow2)
    Cache mode:       writethrough

ide1 (#block577): /home/virtio-win.iso (raw, read-only)
    Removable device: not locked, tray closed
    Cache mode:       writeback

test1 (#block726): /home/pci-bridge/block1.qcow2 (qcow2)
    Cache mode:       writeback

3.In guest, copy some file to the disk which hot-plug through qmp

4.Deleted the disk during copy operation
{"execute":"device_del","arguments":{"id":"test1"}}
{"return": {}}

(qemu) info block
drive-virtio-disk0 (#block137): /home/pci-bridge/win10-1.qcow2 (qcow2)
    Cache mode:       writeback, direct

usbstorage1 (#block383): /home/pci-bridge/usb-disk.qcow2 (qcow2)
    Cache mode:       writethrough

ide1 (#block577): /home/virtio-win.iso (raw, read-only)
    Removable device: not locked, tray closed
    Cache mode:       writeback

test1 (#block726): /home/pci-bridge/block1.qcow2 (qcow2)
    Cache mode:       writeback


Actual results:
Disk didn't be deleted during copy operation, also didn't be deleted after copy operation finished, you must delete the disk again, the disk can be deleted

Expected results:
Disk can be deleted during the copy operation or the copy operation finished

Additional info:
rhel guest didn't hit the issue
Not a regression issue, because can reproduce on qemu-kvm-rhev-2.3.0-31.el7_2.21.x86_64.
Also hit the issue when disk attached to the pci bus