Since the layer store was introduced, the level above the graphdriver
now differentiates between read/write and read-only layers. This
distinction is useful for graphdrivers that need to take special steps
when creating a layer based on whether it is read-only or not.
Adding this parameter allows the graphdrivers to differentiate, which
in the case of the Windows graphdriver, removes our dependence on parsing
the id of the parent for "-init" in order to infer this information.
This will also set the stage for unblocking some of the layer store
unit tests in the next preview build of Windows.
Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>
Upstream-commit: ef5bfad3210a9e9c8b761f2c11c0c6289490ebff
Component: engine