Re: [Qemu-devel] [PATCH 1/2] block: gluster - code movements, state storage changes

[Benoît Canet]

Le Friday 07 Feb 2014 à 09:14:50 (+0530), Bharata B Rao a écrit :
> On Wed, Feb 05, 2014 at 08:25:36PM +0100, Benoît Canet wrote:
> > Le Tuesday 04 Feb 2014 à 14:26:58 (-0500), Jeff Cody a écrit :
> > >  
> > > +static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
> > > +{
> > > +    assert(open_flags != NULL);
> > > +
> > > +    *open_flags |= O_BINARY;
> > > +
> > > +    if (bdrv_flags & BDRV_O_RDWR) {
> > > +        *open_flags |= O_RDWR;
> > > +    } else {
> > > +        *open_flags |= O_RDONLY;
> > > +    }
> > > +
> > > +    if ((bdrv_flags & BDRV_O_NOCACHE)) {
> > > +        *open_flags |= O_DIRECT;
> > > +    }
> > > +}
> > 
> > I saw the enable-O_SYNC option here.
> > http://www.gluster.org/community/documentation/index.php/Translators/performance
> > Why the gluster driver does not allow to enable O_SYNC ?
> 
> I am not aware of any option in QEMU (like cache= etc) that will force
> block driver (like gluster) to use O_SYNC. Do other drivers use O_SYNC ?

[,cache=writethrough|writeback|none|directsync|unsafe][

I think writethough is O_SYNC and directsync is O_DIRECT|O_SYNC.

Best regards

Benoît

> 
> Turning off write-behind for the entire gluster volume isn't an option ?
> 
> Regards,
> Bharata.
>