Description of problem:
Using libiscsi as storage, guest can not reboot/shutdown/poweroff after block mirror from big cluster size to small cluster size image.

Version-Release number of selected component (if applicable):
libiscsi-1.9.0-3.el7.x86_64
qemu-kvm-rhev-1.5.3-19.el7.x86_64
Guest kernel:
2.6.32-430.el6.i686
Host kernel:
3.10.0-48.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.Boot guest with following cli(guest cluster size is 524288).
# /usr/libexec/qemu-kvm -S -M pc-i440fx-rhel7.0.0 -cpu SandyBridge -enable-kvm -m 4G -smp 4,sockets=2,cores=2,threads=1 -name juli -uuid 355a2475-4e03-4cdd-bf7b-5d6a59edaa68 -rtc base=localtime,clock=host,driftfix=slew \
-device virtio-scsi-pci,bus=pci.0,addr=0x5,id=scsi0 -drive file=iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/1,if=none,id=drive-scsi0-0-0,media=disk,cache=none,format=qcow2,werror=stop,rerror=stop,aio=native \
-device scsi-hd,drive=drive-scsi0-0-0,bus=scsi0.0,scsi-id=0,lun=0,id=juli,bootindex=0 \
-drive file=iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/3,if=none,id=drive-virtio0-0-0,media=disk,werror=stop,rerror=stop,cache=none,format=qcow2 -device virtio-blk-pci,bus=pci.0,drive=drive-virtio0-0-0,id=virtio0-0-0 \
-drive file=/home/ISO/en_windows_8.1_preview_x86_dvd_2358833.iso,if=none,media=cdrom,format=raw,aio=native,id=drive-ide1-0-0 -device ide-drive,drive=drive-ide1-0-0,id=ide1-0-0,bus=ide.0,unit=0,bootindex=4 -device virtio-balloon-pci,id=ballooning -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -net none -k en-us -boot menu=on,reboot-timeout=-1,strict=on -qmp tcp:0:4477,server,nowait -serial unix:/tmp/ttyS0,server,nowait -vnc :3 -spice port=5939,disable-ticketing  -vga qxl -global qxl-vga.revision=3 -monitor stdio -monitor tcp:0:7777,server,nowait -monitor unix:/tmp/monitor1,server,nowait -netdev tap,id=tap1,vhost=on,queues=4,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown,ifname=tap-juli -device virtio-net-pci,netdev=tap1,id=nic1,mq=on,vectors=17,mac=1a:59:0a:4b:aa:94
2.create a new qcow2 libiscsi disk image with the same virtual size and default cluster size(65536).
# qemu-img create -f qcow2 -o compat=1.1 iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/1 30G -o cluster_size=65536
# qemu-img info iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/4
image: iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/4
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: unavailable
cluster_size: 524288
Format specific information:
    compat: 0.10
# qemu-img info iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/1
image: iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/1
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: unavailable
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false

Note: above two disks cluster_size are different. 

3.do mirroring via qmp.
{ "execute": "drive-mirror", "arguments": { "device": "drive-scsi0-0-0", "target": "iscsi://10.66.6.82:3260/iqn.2013-11.com.example:storage.disk1.juli.xyz/1", "format": "qcow2", "mode": "existing", "sync": "full", "speed": 1000000000, "on-source-error": "stop", "on-target-error": "stop" } }

4.mirroring should reach steady state correctly and reopen via qmp.
{ "execute" : "query-block-jobs", "arguments" : {} }
{"execute": "block-job-complete", "arguments": { "device": "drive-scsi0-0-0"} }

5.Do reboot/poweroff/shutdown inside guest.
# reboot

Actual results:
# reboot
/sbin/reboot: line 1: �0: command not found
/sbin/reboot: line 2: syntax error near unexpected token `<'
/sbin/reboot: line 2: `<U7332> <U7332>;IGNORE;IGNORE;IGNORE	#猲0'
# poweroff 
/sbin/poweroff: line 1: �0: command not found
/sbin/poweroff: line 2: syntax error near unexpected token `<'
/sbin/poweroff: line 2: `<U7332> <U7332>;IGNORE;IGNORE;IGNORE	#猲0'
# shutdown -h now
/sbin/shutdown: line 1: ORE: command not found
/sbin/shutdown: line 2: syntax error near unexpected token `<'
/sbin/shutdown: line 2: `<U90CA> <U90CA>;IGNORE;IGNORE;IGNORE	#郊1195'

# dmesg
Reserving 128MB of memory at 32MB for crashkernel (System RAM: 4608MB)
kvm-clock: Using msrs 4b564d01 and 4b564d00
kvm-clock: cpu 0, msr 0:b696c1, boot clock
Zone PFN ranges:
  DMA      0x00000001 -> 0x00001000
  Normal   0x00001000 -> 0x000375fe
  HighMem  0x000375fe -> 0x00120000
Movable zone start PFN for each node
early_node_map[3] active PFN ranges
    0: 0x00000001 -> 0x0000009f
    0: 0x00000100 -> 0x000dfffe
    0: 0x00100000 -> 0x00120000
On node 0 totalpages: 1048476
  DMA zone: 32 pages used for memmap
  DMA zone: 0 pages reserved
  DMA zone: 3966 pages, LIFO batch:0
  Normal zone: 1740 pages used for memmap
  Normal zone: 220978 pages, LIFO batch:31
  HighMem zone: 7445 pages used for memmap
  HighMem zone: 814315 pages, LIFO batch:31
Using APIC driver default
ACPI: PM-Timer IO Port: 0xb008
ACPI: Local APIC address 0xfee00000
ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)
ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled)
ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] enabled)
ACPI: LAPIC (acpi_id[0x03] lapic_id[0x03] enabled)
ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1])
ACPI: IOAPIC (id[0x00] address[0xfec00000] gsi_base[0])
IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23
ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level)
ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level)
ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level)
ACPI: IRQ0 used by override.
ACPI: IRQ2 used by override.
ACPI: IRQ5 used by override.
ACPI: IRQ9 used by override.
ACPI: IRQ10 used by override.
ACPI: IRQ11 used by override.
Using ACPI (MADT) for SMP configuration information
SMP: Allowing 4 CPUs, 0 hotplug CPUs
nr_irqs_gsi: 24
PM: Registered nosave memory: 000000000009f000 - 00000000000a0000
PM: Registered nosave memory: 00000000000a0000 - 00000000000f0000
PM: Registered nosave memory: 00000000000f0000 - 0000000000100000
Allocating PCI resources starting at e0000000 (gap: e0000000:1effc000)
Booting paravirtualized kernel on KVM
NR_CPUS:32 nr_cpumask_bits:32 nr_cpu_ids:4 nr_node_ids:1
PERCPU: Embedded 14 pages/cpu @c1e00000 s36056 r0 d21288 u524288
pcpu-alloc: s36056 r0 d21288 u524288 alloc=1*2097152
pcpu-alloc: [0] 0 1 2 3 
kvm-clock: cpu 0, msr 0:1e086c1, primary cpu clock
kvm-stealtime: cpu 0, msr 1e03800
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 1039259
Kernel command line: ro root=/dev/mapper/vg_unused-lv_root rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=us LANG=en_US.UTF-8 rd_LVM_LV=vg_unused/lv_swap rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=128M rd_LVM_LV=vg_unused/lv_root rd_NO_DM rhgb quiet
PID hash table entries: 4096 (order: 2, 16384 bytes)
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Initializing CPU#0
Initializing HighMem for node 0 (000375fe:00120000)
Memory: 4002996k/4718592k available (4504k kernel code, 189736k reserved, 2561k data, 524k init, 3287040k highmem)
virtual kernel memory layout:
    fixmap  : 0xffad5000 - 0xfffff000   (5288 kB)
    pkmap   : 0xff600000 - 0xff800000   (2048 kB)
    vmalloc : 0xf7dfe000 - 0xff5fe000   ( 120 MB)
    lowmem  : 0xc0000000 - 0xf75fe000   ( 885 MB)
      .init : 0xc0ae7000 - 0xc0b6a000   ( 524 kB)
      .data : 0xc0866238 - 0xc0ae6808   (2561 kB)
      .text : 0xc0400000 - 0xc0866238   (4504 kB)
Checking if this processor honours the WP bit even in supervisor mode...Ok.
Hierarchical RCU implementation.
NR_IRQS:2304 nr_irqs:440
Console: colour VGA+ 80x25
console [tty0] enabled
allocated 8388608 bytes of page_cgroup
please try 'cgroup_disable=memory' option if you don't want memory cgroups
Detected 2000.040 MHz processor.
Marking TSC unstable due to TSCs unsynchronized
Calibrating delay loop (skipped) preset value.. 4000.08 BogoMIPS (lpj=2000040)
pid_max: default: 32768 minimum: 301
Security Framework initialized
SELinux:  Initializing.
SELinux:  Starting in permissive mode
Mount-cache hash table entries: 512
Initializing cgroup subsys ns
Initializing cgroup subsys cpuacct
Initializing cgroup subsys memory
Initializing cgroup subsys devices
Initializing cgroup subsys freezer
Initializing cgroup subsys net_cls
Initializing cgroup subsys blkio
Initializing cgroup subsys perf_event
Initializing cgroup subsys net_prio
CPU: Physical Processor ID: 0
CPU: Processor Core ID: 0
mce: CPU supports 10 MCE banks
alternatives: switching to unfair spinlock
ACPI: Core revision 20090903
Enabling APIC mode:  Flat.  Using 1 I/O APICs
..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
CPU0: AMD Intel Xeon E312xx (Sandy Bridge) stepping 01
Performance Events: Broken PMU hardware detected, using software events only.
Booting Node   0, Processors  #1
Initializing CPU#1
kvm-clock: cpu 1, msr 0:1e886c1, secondary cpu clock
------------[ cut here ]------------
WARNING: at arch/x86/kernel/cpu/amd.c:187 init_amd+0x388/0x641() (Not tainted)
Hardware name: KVM
WARNING: This combination of AMD processors is not suitable for SMP.
Modules linked in:
Pid: 0, comm: swapper Not tainted 2.6.32-430.el6.i686 #1
Call Trace:
 [<c045b0d1>] ? warn_slowpath_common+0x81/0xc0
 [<c085585d>] ? init_amd+0x388/0x641
 [<c085585d>] ? init_amd+0x388/0x641
 [<c045b1a3>] ? warn_slowpath_fmt+0x33/0x40
 [<c085585d>] ? init_amd+0x388/0x641
 [<c0854bda>] ? identify_cpu+0x28b/0x42d
 [<c042d65d>] ? default_init_apic_ldr+0x4d/0x50
 [<c08599a0>] ? setup_local_APIC+0x337/0x355
 [<c0854d8c>] ? identify_secondary_cpu+0x10/0x1a
 [<c0858e43>] ? start_secondary+0x138/0x2f4
---[ end trace a7919e7f17c0a725 ]---
Disabling lock debugging due to kernel taint
kvm-stealtime: cpu 1, msr 1e83800
 #2
Initializing CPU#2
kvm-clock: cpu 2, msr 0:1f086c1, secondary cpu clock
kvm-stealtime: cpu 2, msr 1f03800
 #3 Ok.
Initializing CPU#3
kvm-clock: cpu 3, msr 0:1f886c1, secondary cpu clock
Brought up 4 CPUs
Total of 4 processors activated (16000.32 BogoMIPS).
kvm-stealtime: cpu 3, msr 1f83800
sizeof(vma)=100 bytes
sizeof(page)=32 bytes
sizeof(inode)=352 bytes
sizeof(dentry)=132 bytes
sizeof(ext3inode)=508 bytes
sizeof(buffer_head)=56 bytes
sizeof(skbuff)=184 bytes
sizeof(task_struct)=1348 bytes
devtmpfs: initialized
regulator: core version 0.5
NET: Registered protocol family 16
ACPI: bus type pci registered
PCI: PCI BIOS revision 2.10 entry at 0xfc670, last bus=0
PCI: Using configuration type 1 for base access
bio: create slab <bio-0> at 0
ACPI: EC: Look up EC in DSDT
ACPI: Interpreter enabled
ACPI: (supports S0 S3 S4 S5)
ACPI: Using IOAPIC for interrupt routing
ACPI: No dock devices found.
PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
pci_root PNP0A03:00: host bridge window [io  0x0000-0x0cf7]
pci_root PNP0A03:00: host bridge window [io  0x0d00-0xffff]
pci_root PNP0A03:00: host bridge window [mem 0x000a0000-0x000bffff]
pci_root PNP0A03:00: host bridge window [mem 0xe0000000-0xfebfffff]
PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io  0x0000-0x0cf7]
pci_bus 0000:00: root bus resource [io  0x0d00-0xffff]
pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff]
pci_bus 0000:00: root bus resource [mem 0xe0000000-0xfebfffff]
pci 0000:00:01.1: reg 20: [io  0xc100-0xc10f]
pci 0000:00:01.3: quirk: [io  0xb000-0xb03f] claimed by PIIX4 ACPI
pci 0000:00:01.3: quirk: [io  0xb100-0xb10f] claimed by PIIX4 SMB
pci 0000:00:02.0: reg 10: [mem 0xf4000000-0xf7ffffff]
pci 0000:00:02.0: reg 14: [mem 0xf8000000-0xfbffffff]
pci 0000:00:02.0: reg 18: [mem 0xfc030000-0xfc031fff]
pci 0000:00:02.0: reg 1c: [io  0xc0c0-0xc0df]
pci 0000:00:02.0: reg 30: [mem 0xfc020000-0xfc02ffff pref]
pci 0000:00:03.0: reg 10: [io  0xc000-0xc03f]
pci 0000:00:03.0: reg 14: [mem 0xfc032000-0xfc032fff]
pci 0000:00:04.0: reg 10: [io  0xc0e0-0xc0ff]
pci 0000:00:05.0: reg 10: [io  0xc040-0xc07f]
pci 0000:00:05.0: reg 14: [mem 0xfc033000-0xfc033fff]
pci 0000:00:06.0: reg 10: [io  0xc080-0xc0bf]
pci 0000:00:06.0: reg 14: [mem 0xfc034000-0xfc034fff]
pci 0000:00:06.0: reg 30: [mem 0xfc000000-0xfc01ffff pref]
pci_bus 0000:00: on NUMA node 0
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11)
ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11)
ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11)
ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11)
ACPI: PCI Interrupt Link [LNKS] (IRQs *9)
vgaarb: device added: PCI:0000:00:02.0,decodes=io+mem,owns=io+mem,locks=none
vgaarb: loaded
vgaarb: bridge control possible 0000:00:02.0
SCSI subsystem initialized
libata version 3.00 loaded.
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
PCI: Using ACPI for IRQ routing
PCI: pci_cache_line_size set to 64 bytes
lo: Dropping TSO features since no CSUM feature.
NetLabel: Initializing
NetLabel:  domain hash size = 128
NetLabel:  protocols = UNLABELED CIPSOv4
NetLabel:  unlabeled traffic allowed by default
Switching to clocksource kvm-clock
pnp: PnP ACPI init
ACPI: bus type pnp registered
pnp 00:00: [io  0x0cf8-0x0cff]
pnp 00:00: Plug and Play ACPI device, IDs PNP0a03 (active)
pnp 00:01: [io  0x0070-0x0071]
pnp 00:01: [irq 8]
pnp 00:01: [io  0x0072-0x0077]
pnp 00:01: Plug and Play ACPI device, IDs PNP0b00 (active)
pnp 00:02: [io  0x0060]
pnp 00:02: [io  0x0064]
pnp 00:02: [irq 1]
pnp 00:02: Plug and Play ACPI device, IDs PNP0303 (active)
pnp 00:03: [irq 12]
pnp 00:03: Plug and Play ACPI device, IDs PNP0f13 (active)
pnp 00:04: [io  0x03f2-0x03f5]
pnp 00:04: [io  0x03f7]
pnp 00:04: [irq 6]
pnp 00:04: [dma 2]
pnp 00:04: Plug and Play ACPI device, IDs PNP0700 (active)
pnp 00:05: [io  0x03f8-0x03ff]
pnp 00:05: [irq 4]
pnp 00:05: Plug and Play ACPI device, IDs PNP0501 (active)
pnp: PnP ACPI: found 6 devices
ACPI: ACPI bus type pnp unregistered
PCI: max bus depth: 0 pci_try_num: 1
pci_bus 0000:00: resource 4 [io  0x0000-0x0cf7]
pci_bus 0000:00: resource 5 [io  0x0d00-0xffff]
pci_bus 0000:00: resource 6 [mem 0x000a0000-0x000bffff]
pci_bus 0000:00: resource 7 [mem 0xe0000000-0xfebfffff]
NET: Registered protocol family 2
IP route cache hash table entries: 32768 (order: 5, 131072 bytes)
TCP established hash table entries: 131072 (order: 8, 1048576 bytes)
TCP bind hash table entries: 65536 (order: 7, 524288 bytes)
TCP: Hash tables configured (established 131072 bind 65536)
TCP reno registered
NET: Registered protocol family 1
pci 0000:00:00.0: Limiting direct PCI/PCI transfers
pci 0000:00:01.0: PIIX3: Enabling Passive Release
pci 0000:00:01.0: Activating ISA DMA hang workarounds
pci 0000:00:02.0: Boot video device
Trying to unpack rootfs image as initramfs...
Freeing initrd memory: 15837k freed
apm: BIOS not found.
audit: initializing netlink socket (disabled)
type=2000 audit(1384909800.619:1): initialized
highmem bounce pool size: 64 pages
HugeTLB registered 2 MB page size, pre-allocated 0 pages
VFS: Disk quotas dquot_6.5.2
Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
msgmni has been set to 1431
SELinux:  Registering netfilter hooks
alg: No test for stdrng (krng)
ksign: Installing public key data
Loading keyring
- Added public key 6D8C1D71AB3678E6
- User ID: Red Hat, Inc. (Kernel Module GPG key)
- Added public key D4A26C9CCD09BEDA
- User ID: Red Hat Enterprise Linux Driver Update Program <secalert>
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered (default)
pci_hotplug: PCI Hot Plug PCI Core version: 0.5
pciehp: PCI Express Hot Plug Controller Driver version: 0.4
acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
acpiphp: Slot [3] registered
acpiphp: Slot [4] registered
acpiphp: Slot [5] registered
acpiphp: Slot [6] registered
acpiphp: Slot [7] registered
acpiphp: Slot [8] registered
acpiphp: Slot [9] registered
acpiphp: Slot [10] registered
acpiphp: Slot [11] registered
acpiphp: Slot [12] registered
acpiphp: Slot [13] registered
acpiphp: Slot [14] registered
acpiphp: Slot [15] registered
acpiphp: Slot [16] registered
acpiphp: Slot [17] registered
acpiphp: Slot [18] registered
acpiphp: Slot [19] registered
acpiphp: Slot [20] registered
acpiphp: Slot [21] registered
acpiphp: Slot [22] registered
acpiphp: Slot [23] registered
acpiphp: Slot [24] registered
acpiphp: Slot [25] registered
acpiphp: Slot [26] registered
acpiphp: Slot [27] registered
acpiphp: Slot [28] registered
acpiphp: Slot [29] registered
acpiphp: Slot [30] registered
acpiphp: Slot [31] registered
ipmi message handler version 39.2
IPMI System Interface driver.
ipmi_si: Adding default-specified kcs state machine
ipmi_si: Trying default-specified kcs state machine at i/o address 0xca2, slave address 0x0, irq 0
ipmi_si: Interface detection failed
ipmi_si: Adding default-specified smic state machine
ipmi_si: Trying default-specified smic state machine at i/o address 0xca9, slave address 0x0, irq 0
ipmi_si: Interface detection failed
ipmi_si: Adding default-specified bt state machine
ipmi_si: Trying default-specified bt state machine at i/o address 0xe4, slave address 0x0, irq 0
ipmi_si: Interface detection failed
ipmi_si: Unable to find any System Interface(s)
input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input0
ACPI: Power Button [PWRF]
ACPI: acpi_idle registered with cpuidle
ACPI Exception: AE_NOT_FOUND, No or invalid critical threshold (20090903/thermal-386)
GHES: HEST is not enabled!
isapnp: Scanning for PnP cards...
isapnp: No Plug & Play device found
Non-volatile memory driver v1.3
Linux agpgart interface v0.103
crash memory driver: version 1.1
Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:05: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
brd: module loaded
loop: module loaded
input: Macintosh mouse button emulation as /devices/virtual/input/input1
Fixed MDIO Bus: probed
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
uhci_hcd: USB Universal Host Controller Interface driver
PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
serio: i8042 KBD port at 0x60,0x64 irq 1
serio: i8042 AUX port at 0x60,0x64 irq 12
mice: PS/2 mouse device common for all mice
rtc_cmos 00:01: RTC can wake from S4
rtc_cmos 00:01: rtc core: registered rtc_cmos as rtc0
rtc0: alarms up to one day, 114 bytes nvram
cpuidle: using governor ladder
cpuidle: using governor menu
EFI Variables Facility v0.08 2004-May-17
input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input2
usbcore: registered new interface driver hiddev
usbcore: registered new interface driver usbhid
usbhid: v2.6:USB HID core driver
GRE over IPv4 demultiplexor driver
TCP cubic registered
Initializing XFRM netlink socket
NET: Registered protocol family 17
Using IPI No-Shortcut mode
registered taskstats version 1
rtc_cmos 00:01: setting system clock to 2013-11-20 09:10:01 UTC (1384938601)
Initalizing network drop monitor service
Freeing unused kernel memory: 524k freed
Write protecting the kernel text: 4508k
Write protecting the kernel read-only data: 1980k
dracut: dracut-004-335.el6
dracut: rd_NO_LUKS: removing cryptoluks activation
device-mapper: uevent: version 1.0.3
device-mapper: ioctl: 4.24.6-ioctl (2013-01-15) initialised: dm-devel
udev: starting version 147
psmouse serio1: ID: 10 00 64
dracut: Starting plymouth daemon
dracut: rd_NO_DM: removing DM RAID activation
dracut: rd_NO_MD: removing MD RAID activation
ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 11
virtio-pci 0000:00:03.0: PCI INT A -> Link[LNKC] -> GSI 11 (level, high) -> IRQ 11
ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 10
virtio-pci 0000:00:04.0: PCI INT A -> Link[LNKD] -> GSI 10 (level, high) -> IRQ 10
ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 10
virtio-pci 0000:00:05.0: PCI INT A -> Link[LNKA] -> GSI 10 (level, high) -> IRQ 10
ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 11
virtio-pci 0000:00:06.0: PCI INT A -> Link[LNKB] -> GSI 11 (level, high) -> IRQ 11
ata_piix 0000:00:01.1: version 2.13
ata_piix 0000:00:01.1: setting latency timer to 64
scsi0 : ata_piix
scsi1 : ata_piix
ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc100 irq 14
ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc108 irq 15
ata1.01: NODEV after polling detection
ata1.00: ATAPI: QEMU DVD-ROM, 1.5.3, max UDMA/100
ata1.00: configured for MWDMA2
scsi 0:0:0:0: CD-ROM            QEMU     QEMU DVD-ROM     1.5. PQ: 0 ANSI: 5
input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input3
  alloc irq_desc for 24 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:03.0: irq 24 for MSI/MSI-X
  alloc irq_desc for 25 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:03.0: irq 25 for MSI/MSI-X
 vda: vda1 vda2
  alloc irq_desc for 26 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:05.0: irq 26 for MSI/MSI-X
  alloc irq_desc for 27 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:05.0: irq 27 for MSI/MSI-X
  alloc irq_desc for 28 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:05.0: irq 28 for MSI/MSI-X
  alloc irq_desc for 29 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:05.0: irq 29 for MSI/MSI-X
scsi2 : Virtio SCSI HBA
scsi 2:0:0:0: Direct-Access     QEMU     QEMU HARDDISK    1.5. PQ: 0 ANSI: 5
sr0: scsi3-mmc drive: 4x/4x cd/rw xa/form2 tray
Uniform CD-ROM driver Revision: 3.20
sr 0:0:0:0: Attached scsi CD-ROM sr0
sd 2:0:0:0: [sda] 62914560 512-byte logical blocks: (32.2 GB/30.0 GiB)
sd 2:0:0:0: [sda] Write Protect is off
sd 2:0:0:0: [sda] Mode Sense: 63 00 00 08
sd 2:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sda: sda1 sda2
sd 2:0:0:0: [sda] Attached SCSI disk
dracut: Scanning devices sda2 vda2  for LVM logical volumes vg_unused/lv_swap vg_unused/lv_root 
dracut: Found duplicate PV KR0iAw7ZIxbzalquR0vjeyAEWGK3uRGh: using /dev/vda2 not /dev/sda2
dracut: inactive '/dev/vg_unused/lv_root' [26.51 GiB] inherit
dracut: inactive '/dev/vg_unused/lv_swap' [3.00 GiB] inherit
dracut: Found duplicate PV KR0iAw7ZIxbzalquR0vjeyAEWGK3uRGh: using /dev/vda2 not /dev/sda2
EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: 
dracut: Mounted root filesystem /dev/mapper/vg_unused-lv_root
dracut: Loading SELinux policy
type=1404 audit(1384938603.458:2): enforcing=1 old_enforcing=0 auid=4294967295 ses=4294967295
SELinux: 2048 avtab hash slots, 277800 rules.
SELinux: 2048 avtab hash slots, 277800 rules.
SELinux:  9 users, 12 roles, 3917 types, 217 bools, 1 sens, 1024 cats
SELinux:  81 classes, 277800 rules
SELinux:  Completing initialization.
SELinux:  Setting up existing superblocks.
SELinux: initialized (dev dm-0, type ext4), uses xattr
SELinux: initialized (dev tmpfs, type tmpfs), uses transition SIDs
SELinux: initialized (dev selinuxfs, type selinuxfs), uses genfs_contexts
SELinux: initialized (dev mqueue, type mqueue), uses transition SIDs
SELinux: initialized (dev hugetlbfs, type hugetlbfs), uses transition SIDs
SELinux: initialized (dev devpts, type devpts), uses transition SIDs
SELinux: initialized (dev inotifyfs, type inotifyfs), uses genfs_contexts
SELinux: initialized (dev anon_inodefs, type anon_inodefs), uses genfs_contexts
SELinux: initialized (dev pipefs, type pipefs), uses task SIDs
SELinux: initialized (dev debugfs, type debugfs), uses genfs_contexts
SELinux: initialized (dev sockfs, type sockfs), uses task SIDs
SELinux: initialized (dev devtmpfs, type devtmpfs), uses transition SIDs
SELinux: initialized (dev tmpfs, type tmpfs), uses transition SIDs
SELinux: initialized (dev proc, type proc), uses genfs_contexts
SELinux: initialized (dev bdev, type bdev), uses genfs_contexts
SELinux: initialized (dev rootfs, type rootfs), uses genfs_contexts
SELinux: initialized (dev sysfs, type sysfs), uses genfs_contexts
type=1403 audit(1384938604.020:3): policy loaded auid=4294967295 ses=4294967295
dracut: 
dracut: Switching root
SELinux: initialized (dev usbfs, type usbfs), uses genfs_contexts
udev: starting version 147
piix4_smbus 0000:00:01.3: SMBus Host Controller at 0xb100, revision 0
  alloc irq_desc for 30 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:06.0: irq 30 for MSI/MSI-X
  alloc irq_desc for 31 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:06.0: irq 31 for MSI/MSI-X
  alloc irq_desc for 32 on node -1
  alloc kstat_irqs on node -1
virtio-pci 0000:00:06.0: irq 32 for MSI/MSI-X
sr 0:0:0:0: Attached scsi generic sg0 type 5
sd 2:0:0:0: Attached scsi generic sg1 type 0
platform microcode: firmware: requesting amd-ucode/microcode_amd.bin
microcode: CPU0: AMD CPU family 0x6 not supported
microcode: CPU1: AMD CPU family 0x6 not supported
microcode: CPU2: AMD CPU family 0x6 not supported
microcode: CPU3: AMD CPU family 0x6 not supported
Microcode Update Driver: v2.00 <tigran.co.uk>, Peter Oruba
EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: 
SELinux: initialized (dev sda1, type ext4), uses xattr
Adding 3145720k swap on /dev/mapper/vg_unused-lv_swap.  Priority:-1 extents:1 across:3145720k 
SELinux: initialized (dev binfmt_misc, type binfmt_misc), uses genfs_contexts
NET: Registered protocol family 10
lo: Disabled Privacy Extensions
ip6_tables: (C) 2000-2006 Netfilter Core Team
nf_conntrack version 0.5.0 (16384 buckets, 65536 max)
ip_tables: (C) 2000-2006 Netfilter Core Team
802.1Q VLAN Support v1.8 Ben Greear <greearb>
All bugs added by David S. Miller <davem>
8021q: adding VLAN 0 to HW filter on device eth0
SELinux: initialized (dev autofs, type autofs), uses genfs_contexts
SELinux: initialized (dev autofs, type autofs), uses genfs_contexts
SELinux: initialized (dev autofs, type autofs), uses genfs_contexts
eth0: no IPv6 routers present

Expected results:
After block mirror, guest can reboot/shutdown/poweroff as normal.

Additional info:
Most of commands inside guest can works well(such as: ping/ls/dmesg/fdisk/df can works well). 
Quit qemu-kvm and boot with this new disk image(mirror disk image) again, guest can works well. Can do reboot/shutdown/poweroff as normal.