Re: [Qemu-devel] [PATCH for-2.10 3/9] block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only

[Jeff Cody]

On Wed, Apr 05, 2017 at 02:26:53PM -0500, Eric Blake wrote:
> On 04/05/2017 02:20 PM, John Snow wrote:
> 
> > Conceptually straightforward.
> > 
> > looks like this might change behavior for... RBD and vvfat, right?
> > RBD is the subject of this series so we'll just assume that was broken
> > and stupid.
> > 

Yes on RBD, and that change is intentional.

> > What's vvfat's story? It always set the read-only property to false
> > regardless of what you asked for?
> 
> vvfat is even stupider than that - it has its own independent property
> 'rw' that determines whether to allow write operations, separate from
> the inherited BDS readonly property.
>

Yes, it is very odd.  But if we have copy_on_read enabled, or explicitly set
the block device to read-only via QAPI or -drive, I think that those should
take precedence.