On Fri, 10/21 22:45, Max Reitz wrote: > On 30.09.2016 14:09, Fam Zheng wrote: > > Signed-off-by: Fam Zheng <f...@redhat.com> > > --- > > qapi/block-core.json | 18 ++++++++++++++++++ > > 1 file changed, 18 insertions(+) > > > > diff --git a/qapi/block-core.json b/qapi/block-core.json > > index 92193ab..22e8d04 100644 > > --- a/qapi/block-core.json > > +++ b/qapi/block-core.json > > @@ -2754,3 +2754,21 @@ > > 'data' : { 'parent': 'str', > > '*child': 'str', > > '*node': 'str' } } > > + > > +## > > +# @ImageLockMode: > > +# > > +# @auto: defer to the block driver to use the least strict mode, based on > > +# the nature of format and read-only flag, and the supported locking > > +# operations of the protocol. > > I have some difficulty understanding this description. I'd intuitively > assume no locking to be the "least strict mode"; however, since it > should be always possible not to lock an image, this would mean that > auto=nolock. Which is hopefully isn't. > > If it's not easy to come up with a thorough explanation, perhaps it > would be best to give some examples which help to understand the concept > behind "auto" intuitively.
It could have beeen more specific, it's my bad being too terse here. Maybe something like this: @auto: defer to the block layer to use an appropriate lock mode, based on the driver used and read-only option: for read-only images, shared lock mode, or otherwise exclusive lock mode, will be attempted; if the driver doesn't support this mode (or sharing is particularly desired by its design), nolock will be used. ? Fam