Re: [PATCH] doc: Describe missing generic -blockdev options

[Eric Blake <eblake@redhat.com>]

On 10/15/19 7:38 AM, Kevin Wolf wrote:
> We added more generic options after introducing -blockdev and forgot to
> update the documentation (man page and --help output) accordingly. Do
> that now.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   qemu-options.hx | 19 ++++++++++++++++++-
>   1 file changed, 18 insertions(+), 1 deletion(-)
> 

> @@ -885,6 +886,22 @@ name is not intended to be predictable and changes between QEMU invocations.
>   For the top level, an explicit node name must be specified.
>   @item read-only
>   Open the node read-only. Guest write attempts will fail.
> +
> +Note that some block drivers support only read-only access, either generally or
> +in certain configurations. In this case, the default value
> +@option{read-only=off} does not work and the option must be specified
> +explicitly.
> +@item auto-read-only
> +If @option{auto-read-only=on} is set, QEMU is allowed not to open the image
> +read-write even if @option{read-only=off} is requested, but fall back to
> +read-only instead (and switch between the modes later), e.g. depending on
> +whether the image file is writable or whether a writing user is attached to the
> +node.

Hard to read.  Maybe:

If @option{auto-read-only=on} is set, QEMU may fall back to read-only 
usage even when @option{read-only=off} is requested, or even switch 
between modes as needed, e.g. depending on whether the image file is 
writable or whether a writing user is attached to the node.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org