This showed up in a recent profile. Search doesn't need to take a lock on the store, because digestset has its own locking. Some other methods can get by with a read lock instead of an exclusive lock. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com> Upstream-commit: 44e67adae5695e3e2c3b450453ab0fe6119eb80d Component: engine