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Description of problem:
Configure the NFS and mount it, boot a guest with a data disk enable data-plane located on NFS storage, disconnect the NFS server during some I/O to the data disk in guest, then resume the paused guest by running "cont" in monitor after reconnect NFS server. But qemu fail to general EIO and guest kernel call trace if enable data-plane when disconnect the NFS server. btw, this is a regression issue.
Version-Release number of selected component (if applicable):
host info:
# uname -r && rpm -q qemu-kvm
2.6.32-355.el6.x86_64
qemu-kvm-0.12.1.2-2.352.el6.x86_64
How reproducible:
100%
Steps to Reproduce:
1.configure the NFS and mount it.
# cat /etc/exports
/home *(rw,no_root_squash,sync)
# mount -o soft,timeo=15,retrans=3,nosharecache $nfs_server_ip:/home/ /mnt/
2.boot a guest with a data disk(werror=stop,rerror=stop) located on NFS storage.
e.g:...-drive file=/mnt/my-data-disk.raw,if=none,id=drive-virtio-disk,format=raw,cache=none,aio=native,werror=stop,rerror=stop -device virtio-blk-pci,serial="QEMU-DISK2",bus=pci.0,addr=0x9,scsi=off,x-data-plane=on,drive=drive-virtio-disk,id=virtio-disk,serial="QEMU-DISK2"
3.disconnect the NFS server during some I/O to the data disk in guest.
# service nfs stop
4.reconnect NFS server.
# service nfs restart
5.resume the paused guest by running "cont" in monitor.
Actual results:
after step 3, qemu fail to general EIO and guest kernel output many 'I/O error' and call trace.
Expected results:
qemu general EIO successfully, the VM was in paused status without any problem, and then guest can be resumed successfully after the nfs re-connect.
Additional info:
My gest info:
kernel-2.6.32-355.el6.x86_64
The qemu fail to general EIO and guest kernel call trace if enable data-plane when disconnect the NFS server, and the VM tatus is still running, like:
(qemu) info status
VM status: running
(qemu) info status
VM status: running
The expected result like:
(qemu) block I/O error in device 'drive-virtio-disk': Input/output error (5)
block I/O error in device 'drive-virtio-disk': Input/output error (5)
block I/O error in device 'drive-virtio-disk': Input/output error (5)
block I/O error in device 'drive-virtio-disk': Input/output error (5)
...
(qemu) info status
VM status: paused (io-error)
(In reply to comment #3)
> My gest info:
> kernel-2.6.32-355.el6.x86_64
>
> The qemu fail to general EIO and guest kernel call trace if enable
> data-plane when disconnect the NFS server, and the VM tatus is still
> running, like:
> (qemu) info status
> VM status: running
> (qemu) info status
> VM status: running
>
> The expected result like:
> (qemu) block I/O error in device 'drive-virtio-disk': Input/output error (5)
> block I/O error in device 'drive-virtio-disk': Input/output error (5)
> block I/O error in device 'drive-virtio-disk': Input/output error (5)
> block I/O error in device 'drive-virtio-disk': Input/output error (5)
> ...
> (qemu) info status
> VM status: paused (io-error)
This is expected behavior because x-data-plane=on does not implement -drive werror=...,rerror=.... The only supported error policy is to report host I/O errors to the guest. The guest is not paused when an I/O error occurs.
Other error handling policies will be supported by virtio-blk-data-plane in the future. There is no immediate fix for this, it will be supported when hw/virtio-blk.c is refactored to run in the data-plane thread.