Bug 1345830

polarion cases steps:

1.Boot guest with **/dev/sdc** (generaled as **setup**) with virtio serial and
start guest agent inside guest.
Refer to case: <https://tcms.engineering.redhat.com/case/135941/>.
e.g:...-drive file=/dev/sdc,if=none,id=drive-data-disk,format=**raw**,cache=no
ne,aio=native,werror=stop,rerror=stop****,**discard=on **-device virtio-scsi-
pci,id=scsi1,bus=pci.0,addr=0x8-device **scsi-block**,drive=drive-data-
disk,bus=scsi1.0,id=data-disk \
-chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 -device virtio-serial -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
1.after step 1, boot guest successfully.



2.Make file system to the disk in the guest.
# mkfs.ext4 /dev/sdb	2.after step 3,
# cat /sys/bus/pseudo/drivers/scsi_debug/map
1-616,16257-16383
3. On the host
# cat /sys/bus/pseudo/drivers/scsi_debug/map	3.after step 5,
# cat /sys/bus/pseudo/drivers/scsi_debug/map
1-616,645-1588,1599-4026,4029-16383
4.On the guest
# mount /dev/sdb /home/test
# dd if=/dev/zero of=/home/test/file	4.after step 7,
{"execute":"guest-fstrim"}
{"return": {}}
5.cat map in host.
# cat /sys/bus/pseudo/drivers/scsi_debug/map	5.after step 8,
# cat /sys/bus/pseudo/drivers/scsi_debug/map
**1-612**
6.in guest.
# rm /home/test/file	
7.connect the chardev socket in host side and send "guest-fstrim" command in
the host side:
# nc -U /tmp/qga.sock
{"execute":"guest-fstrim"}	
8.cat map in host.
# cat /sys/bus/pseudo/drivers/scsi_debug/map


i followed the case steps to find this problem ,if it is wrong ,please help to correct me ,thanks.

Your command line has two "-drive":

    -drive id=drive_image1,if=none,cache=none,snapshot=off,aio=native,format=qcow2,file=/home/RHEL-Server-7.3-64-virtio-scsi.qcow2 \
    ...
    -drive file=/home/100M.qcow2,if=none,id=drive-data-disk,format=raw,cache=none,aio=native,werror=stop,rerror=stop,discard=on \

both of which are qcow2 images under /home, how is it related to scsi_debug and thin-provisioning?

Also please make check that your host filesystem is not 100% full, because if so, the stop is expected (werror=stop).

(In reply to Fam Zheng from comment #3)
> Your command line has two "-drive":
> 
>     -drive
> id=drive_image1,if=none,cache=none,snapshot=off,aio=native,format=qcow2,
> file=/home/RHEL-Server-7.3-64-virtio-scsi.qcow2 \
>     ...
>     -drive
> file=/home/100M.qcow2,if=none,id=drive-data-disk,format=raw,cache=none,
> aio=native,werror=stop,rerror=stop,discard=on \
> 
> both of which are qcow2 images under /home, how is it related to scsi_debug
> and thin-provisioning?

sorry ,i paste the wrong commandline, modified it to:

modify the qemu commandline to:

MALLOC_PERTURB_=1  /usr/libexec/qemu-kvm \
    -name 'avocado-vt-vm1'  \
    -sandbox off  \
    -machine pc  \
    -nodefaults  \
    -vga cirrus  \
    -chardev socket,id=qmp_id_qmpmonitor1,path=/var/tmp/monitor-qmpmonitor1,server,nowait \
    -mon chardev=qmp_id_qmpmonitor1,mode=control  \
    -chardev socket,id=qmp_id_catch_monitor,path=/var/tmp/omonitor-catch_monitor-20160613-034403-23Mgrt5K,server,nowait \
    -mon chardev=qmp_id_catch_monitor,mode=control \
    -device pvpanic,ioport=0x505,id=id7sDMld  \
    -device ich9-usb-ehci1,id=usb1,addr=1d.7,multifunction=on,bus=pci.0 \
    -device ich9-usb-uhci1,id=usb1.0,multifunction=on,masterbus=usb1.0,addr=1d.0,firstport=0,bus=pci.0 \
    -device ich9-usb-uhci2,id=usb1.1,multifunction=on,masterbus=usb1.0,addr=1d.2,firstport=2,bus=pci.0 \
    -device ich9-usb-uhci3,id=usb1.2,multifunction=on,masterbus=usb1.0,addr=1d.4,firstport=4,bus=pci.0 \
    -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pci.0,addr=03,disable-legacy=off,disable-modern=on \
    -drive id=drive_image1,if=none,cache=none,snapshot=off,aio=native,format=qcow2,file=/home/RHEL-Server-7.3-64-virtio-scsi.qcow2 \
    -device scsi-hd,id=image1,drive=drive_image1 \
    -device virtio-net-pci,mac=9a:e8:e9:ea:eb:ec,id=idPUX3Se,vectors=4,netdev=id70bfyc,bus=pci.0,addr=04,disable-legacy=off,disable-modern=on  \
    -netdev tap,id=id70bfyc,vhost=on \
    -m 8192  \
    -smp 8,maxcpus=8,cores=4,threads=1,sockets=2  \
    -cpu 'Opteron_G3',+kvm_pv_unhalt \
    -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1  \
    -vnc :0  \
    -rtc base=utc,clock=host,driftfix=slew  \
    -boot order=cdn,once=c,menu=off,strict=off \
    -enable-kvm \
    -monitor stdio \
    -drive file=/dev/sdb,if=none,id=drive-data-disk,format=raw,cache=none,aio=native,werror=enospc,rerror=report,discard=on \
    -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x8 \
    -device scsi-block,drive=drive-data-disk,bus=scsi1.0,id=data-disk \
    -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 \
    -device virtio-serial \
    -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0 \

(In reply to Fam Zheng from comment #4)
> Also please make check that your host filesystem is not 100% full, because
> if so, the stop is expected (werror=stop).

when i issue dd command ,the guest hangs ,can you provide a way to check the filesystem ,thanks.

and do you mean if i use werror=stop,rerror=stop ,it will hang and the hmp monitor should show io-error when i issue "info status"

i think it should show like the following and the guest should not hang.

[root@bootp-73-199-1 home]# mount /dev/sdb /home/test
[root@bootp-73-199-1 home]# dd if=/dev/zero of=/home/test/file
dd: writing to ‘/home/test/file’: No space left on device
976777+0 records in
976776+0 records out
500109312 bytes (500 MB) copied, 6.79864 s, 73.6 MB/s



BTW: if use werror=enospc,rerror=report , guset will not hang and just give warnings "No space left on device"

if i was wrong, please help correct ,thanks.

(In reply to Yang Meng from comment #6)
> and do you mean if i use werror=stop,rerror=stop ,it will hang and the hmp
> monitor should show io-error when i issue "info status"

Yes, "stop" is expected, because your host filesystem is full, and it is an io-error which will be captured by werror=. And you werror= is 'stop'.

(In reply to Fam Zheng from comment #7)
> (In reply to Yang Meng from comment #6)
> > and do you mean if i use werror=stop,rerror=stop ,it will hang and the hmp
> > monitor should show io-error when i issue "info status"
> 
> Yes, "stop" is expected, because your host filesystem is full, and it is an
> io-error which will be captured by werror=. And you werror= is 'stop'.

thanks for your explanation.

BTW, i tried with image file like:
    -drive file=/home/1G.raw,if=none,id=drive-data-disk,format=raw,cache=none,aio=native,werror=stop,rerror=stop \
    -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x8 \
    -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk \

why it didn't cause io-error in hmp monitor and just got "dd: writing to ‘/home/test/file’: No space left on device",could you help to explain the difference,thanks

This is because in this case, stop only happens when the _host_ disk is full.