Implement metadata probe functionality to load cache state
from disk.
During metadata probe, we inspect UUIDs of core devices
and create vbdev configurations based on them.
Then, to start vbdev, we use load path (loadq = true).
After this change persistent metadata is officially supported,
we can save and restore cache state from persistant storage.
WriteBack mode is now safe to use in respect to unexpected shutdowns,
because all information about dirty data is also restored during cache load.
Change-Id: I6cf86aabd68177b88638a68ea6a5b78a1068a4d0
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/455417
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
9686948334