Imporve healing and reporting (#11312)

* Provide information on *actively* healing, buckets healed/queued, objects healed/failed.
* Add concurrent healing of multiple sets (typically on startup).
* Add bucket level resume, so restarts will only heal non-healed buckets.
* Print summary after healing a disk is done.

cmd/xl-storage-format-utils.go

@@ -94,3 +94,16 @@ func getFileInfo(xlMetaBuf []byte, volume, path, versionID string) (FileInfo, er
 	fi.XLV1 = true // indicates older version
 	return fi, err
 }
+
+// getXLDiskLoc will return the pool/set/disk id if it can be located in the object layer.
+// Will return -1 for unknown values.
+func getXLDiskLoc(diskID string) (poolIdx, setIdx, diskIdx int) {
+	if api := newObjectLayerFn(); api != nil {
+		if ep, ok := api.(*erasureServerPools); ok {
+			if pool, set, disk, err := ep.getPoolAndSet(diskID); err == nil {
+				return pool, set, disk
+			}
+		}
+	}
+	return -1, -1, -1
+}