Re: [Qemu-devel] Block format 'raw' does not support the option 'locking' when disable image locking with option locking=off

[Changlimin]

share-rw=on is good for raw format file, but bad for qcow2 format file:

Failed to get "write" lock
Is another process using the image?

Is this intented?

BR
Chang Limin

-----Original Message-----
From: Fam Zheng [mailto:address@hidden 
Sent: Wednesday, October 25, 2017 9:31 PM
To: changlimin 00148 (Cloud)
Cc: address@hidden
Subject: Re: [Qemu-devel] Block format 'raw' does not support the option 
'locking' when disable image locking with option locking=off

On Wed, 10/25 08:15, Changlimin wrote:
> Hi,
> When running Oracle RAC, one image is shared between multiple vms, so I want 
> to disable locking with option locking=off, But Block format 'raw' does not 
> support the option 'locking'.
> How to disable locking?
> 
> The version is git e822e81e350825dd94f41ee2538ff1432b812eb9
> 
> The command line is
> -drive 
> file=/var/lib/libvirt/images/r0605-share.img,format=raw,if=none,id=dri
> ve-virtio-disk1,cache=directsync,aio=native,locking=off \ -device 
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0xa,drive=drive-virtio-disk1,id
> =virtio-disk1 \

Hi, in this case you probably want to use share-rw=on:

 -device virtio-blk-pci,share-rw=on,scsi=off,...

The -drive option is the same. This is more semantically correct than 
locking=off as it means "the device can share the image with other QEMUs".

But for really disabling locking with "locking=off", the right syntax is:

 -drive file.filename=/var/lib/...,file.locking=off \

or alternatively:

 -drive driver=file,filename=/var/lib/...,locking=off \

Fam