- abstract out instrumentation information.
- use separate lockInstance type that encapsulates the nsMutex, volume,
path and opsID as the frontend or top-level lock object.
- When modifying notification configuration
- When modifying listener configuration
- When modifying policy configuration
With this change we also stop early checking if the bucket exists, since
that uses a Read-lock and causes a deadlock due to the outer Write-lock.
Current master has a regression 'mc policy <policy-type> alias/bucket/prefix'
does not work anymore, due to the way new minio-go changes do json marshalling.
This led to a regression on server side when a ``prefix`` is provided
policy is rejected as malformed from th server which is not the case with
AWS S3.
This patch uses the new ``minio-go/pkg/set`` package to address the
unmarshalling problems.
Fixes#2503
