Hello,
I've been tring to use QEMU-1.5.0 and Libvirt-1.1.0 to run a VM with a nbd
network disk, the VM is created by Libvirt as follow(Please attention to the
red words):
root@xxx-11:~# ps -ef | grep kvm
root 1647 2 0 Feb05 ? 00:00:00 [kvm-irqfd-clean]
root 8304 1 37 14:48 ? 00:00:03 /usr/bin/kvm -name wfg-vm -S
-machine pc-i440fx-1.5,accel=kvm,usb=off,system=windows -m 1024 -realtime
mlock=0 -smp 1,maxcpus=4,sockets=4,cores=1,threads=1 -uuid
5c99f1f4-6d50-4e4e-b2f6-000750a5a154 -no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/wfg-vm.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc
base=localtime,clock=vm,driftfix=slew -no-hpet -no-shutdown -device
piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device
usb-ehci,id=ehci,bus=pci.0,addr=0x4 -device
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive
file=/vms/images/wfg-vm,if=none,id=drive-ide0-0-0,format=qcow2,cache=directsync
-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive
file=nbd:192.168.0.188:20002,if=none,id=drive-ide0-0-1,readonly=on -device
ide-cd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1,bootindex=1 -drive
if=none,id=drive-ide0-1-0,readonly=on,format=raw -device
ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev
tap,fd=21,id=hostnet0 -device
rtl8139,netdev=hostnet0,id=net0,mac=0c:da:41:1d:98:62,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0
-chardev
socket,id=charchannel0,path=/var/lib/libvirt/qemu/wfg-vm.agent,server,nowait
-device
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0
-device usb-tablet,id=input0,bus=usb.0 -vnc 0.0.0.0:0 -device
VGA,id=video0,bus=pci.0,addr=0x2 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6
If the nbd server is running correctely, the VM will start successfully, is
seems every think is OK.
But, if the server is crashed or the network become unreachable, then comes the
problem, the VM's process will keep writing log to file /var/log/libvirt/qemu/
wfg-vm.log all the time, and make the disk full finally!
The log is as follow:
2014-02-18 03:25:04.702+0000: starting up
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
QEMU_AUDIO_DRV=none /usr/bin/kvm -name wfg-vm -S -machine
pc-i440fx-1.5,accel=kvm,usb=off,system=windows -m 1024 -realtime mlock=0 -smp
1,maxcpus=4,sockets=4,cores=1,threads=1 -uuid
5c99f1f4-6d50-4e4e-b2f6-000750a5a154 -no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/wfg-vm.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc
base=localtime,clock=vm,driftfix=slew -no-hpet -no-shutdown -device
piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device
usb-ehci,id=ehci,bus=pci.0,addr=0x4 -device
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive
file=/vms/images/wfg-vm,if=none,id=drive-ide0-0-0,format=qcow2,cache=directsync
-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1
-drive file=nbd:192.168.0.190:10809,if=none,id=drive-ide0-0-1,readonly=on
-device ide-cd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1,bootindex=2
-drive if=none,id=drive-ide0-1-0,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 -device
rtl8139,netdev=hostnet0,id=net0,mac=0c:da:41:1d:98:62,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0
-chardev
socket,id=charchannel0,path=/var/lib/libvirt/qemu/wfg-vm.agent,server,nowait
-device
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0
-device usb-tablet,id=input0,bus=usb.0 -vnc 0.0.0.0:0 -device
VGA,id=video0,bus=pci.0,addr=0x2 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6
Domain id=4 is tainted: high-privileges
char device redirected to /dev/pts/6 (label charserial0)
nbd.c:nbd_receive_reply():L746: read failed, ret(0) diff from size(16)
nbd.c:nbd_receive_reply():L746: read failed, ret(0) diff from size(16)
nbd.c:nbd_receive_reply():L746: read failed, ret(0) diff from size(16)
nbd.c:nbd_receive_reply():L746: read failed, ret(0) diff from size(16)
nbd.c:nbd_receive_reply():L746: read failed, ret(0) diff from size(16)
.......
I have review the context of the function nbd_receive_reply, and found that
function qemu_recv return -1 with errno 104 when the nbd server down, but it
seems the upper caller nbd_reply_ready dose not take care this situation and
return noting, the upper caller does not aware the ERROR, and request comes
continue and keep logging ........
Here is a piece of code:
static void nbd_reply_ready(void *opaque)
{
BDRVNBDState *s = opaque;
uint64_t i;
int ret;
if (s->reply.handle == 0) {
/* No reply already in flight. Fetch a header. It is possible
* that another thread has done the same thing in parallel, so
* the socket is not readable anymore.
*/
ret = nbd_receive_reply(s->sock, &s->reply);
if (ret == -EAGAIN) {
return;
}
if (ret < 0) { ////in case of nbd server down, ret value is -104;
I think in this case, there should be a way to deliver the ERROR to the upper
level, and the s->sock should be closed, such as call nbd_teardown_connection
s->reply.handle = 0;
goto fail;
}
}
Thank you in advance.
caizhifeng...@163.com<mailto:caizhifeng...@163.com>
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