Re: [Qemu-devel] Re: [PATCH] block: Enable fall-back to read-only for backing file

2010-02-01 Thread Jamie Lokier
Christoph Hellwig wrote: > On Mon, Feb 01, 2010 at 10:25:52AM +0100, Alexander Graf wrote: > > We don't know beforehand if a user will use the commit comnand during > > tje runtime of the vm. > > > > IMHO it'd be best to always open backing files read only and try to > > open them for write ac

Re: [Qemu-devel] Re: [PATCH] block: Enable fall-back to read-only for backing file

2010-02-01 Thread Alexander Graf
Christoph Hellwig wrote: > On Mon, Feb 01, 2010 at 10:25:52AM +0100, Alexander Graf wrote: > >> We don't know beforehand if a user will use the commit comnand during >> tje runtime of the vm. >> >> IMHO it'd be best to always open backing files read only and try to >> open them for write acc

Re: [Qemu-devel] Re: [PATCH] block: Enable fall-back to read-only for backing file

2010-02-01 Thread Christoph Hellwig
On Mon, Feb 01, 2010 at 10:25:52AM +0100, Alexander Graf wrote: > We don't know beforehand if a user will use the commit comnand during > tje runtime of the vm. > > IMHO it'd be best to always open backing files read only and try to > open them for write access on the commit command. That comm

Re: [Qemu-devel] Re: [PATCH] block: Enable fall-back to read-only for backing file

2010-02-01 Thread Alexander Graf
Am 01.02.2010 um 10:06 schrieb Christoph Hellwig : On Mon, Feb 01, 2010 at 09:46:00AM +0100, Kevin Wolf wrote: Is it better to always open the backing file with read-only mode ? this will be more consistent/predictable ? I would love to open them read-only unconditionally, but we can't. It

Re: [Qemu-devel] Re: [PATCH] block: Enable fall-back to read-only for backing file

2010-02-01 Thread Christoph Hellwig
On Mon, Feb 01, 2010 at 09:46:00AM +0100, Kevin Wolf wrote: > > Is it better to always open the backing file with read-only mode ? this > > will be more consistent/predictable ? > > I would love to open them read-only unconditionally, but we can't. It > would break the commit monitor command. I t

[Qemu-devel] Re: [PATCH] block: Enable fall-back to read-only for backing file

2010-02-01 Thread Kevin Wolf
Am 31.01.2010 17:49, schrieb Naphtali Sprei: > There's a problem when trying to use an image file based on a read-only image > file. > Before this patch, qemu fails to open the base image and stop. > With this patch, qemu tries to open the backing file with same permissions as > the "top" file, >