Re: [Qemu-devel] sheepdog block driver and read write error policy

[Fam Zheng]

On Thu, 11/16 11:11, Vasiliy Tolstov wrote:
> Hi. I'm try to write own sheepdog compatible daemon and test it with qemu.
> Sometimes ago in qemu added read write error policy to allow to stop
> domain or continue or something else. As i see in case of sheepdog
> this policy is ignored and qemu try to reconnect to sheepdog daemon.
> If nobody wants i can try to fix this, and if policy is not specified
> work like now.
> Where i need to start to easy understand how this works in case of file raw ?

The driver callbacks (sd_co_readv/sd_co_writev) should simply return error
instead of retrying.

> 
> Also i'm fedora user with virt-preview repo and see, that if sheepdog
> daemon is unavailable 2 or more minutes and started after that qemu
> crashed. Does i need to retest with latest qemu version?
> b2587932582333197c88bf663785b19f441989d7
> f1af3251f885f3b8adf73ba078500f2eeefbedae
> 5eceb01adfbe513c0309528293b0b86e32a6e27d
> 
> 
> qemu-system-x86_64 -machine q35 -accel kvm -m 512M -vnc 0.0.0.0:1
> -device virtio-scsi-pci,id=scsi0 -drive
> aio=native,rerror=stop,werror=stop,if=none,format=raw,id=drive-scsi-disk0,cache=none,file=sheepdog:test,discard=unmap,detect-zeroes=off
>  -device scsi-hd,bus=scsi0.0,drive=drive-scsi-disk0,id=device-scsi-disk0
> qemu-system-x86_64: failed to get the header, Invalid argument
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: failed to send a req, Bad file descriptor
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> qemu-system-x86_64: Failed to connect socket: Connection refused
> 
> 
> 
> qemu-system-x86_64: /builddir/build/BUILD/qemu-2.9.0/util/iov.c:167:
> iov_send_recv: Assertion `niov < iov_cnt' failed.
> Makefile:5: recipe for target 'test' failed
> make: *** [test] Aborted (core dumped)
> 
> And if someone from fedora/redhat team is present - when new qemu
> version available in virt preview repo for fedora 25 or it EOL?

It's recommended to use qemu.git if you want to develop new features for QEMU:

http://wiki.qemu.org/Contribute

Fam