// Examines /proc/mounts to find the source device of the PD resource and the // number of references to that device. Returns both the full device path under // the /dev tree and the number of references. func getMountRefCount(mounter mount.Interface, mountPath string) (string, int, error) { // TODO(jonesdl) This can be split up into two procedures, finding the device path // and finding the number of references. The parsing could also be separated and another // utility could determine if a path is an active mount point. mps, err := mounter.List() if err != nil { return "", -1, err } // Find the device name. deviceName := "" for i := range mps { if mps[i].Path == mountPath { deviceName = mps[i].Device break } } // Find the number of references to the device. refCount := 0 for i := range mps { if mps[i].Device == deviceName { refCount++ } } return deviceName, refCount, nil }
// getDevicePrefixRefCount: given a prefix of device path, find its reference count from /proc/mounts // returns the reference count to the device and error code // for services like iscsi construct multiple device paths with the same prefix pattern. // this function aggregates all references to a service based on the prefix pattern // More specifically, this prefix semantics is to aggregate disk paths that belong to the same iSCSI target/iqn pair. // an iSCSI target could expose multiple LUNs through the same IQN, and Linux iSCSI initiator creates disk paths that start the same prefix but end with different LUN number // When we decide whether it is time to logout a target, we have to see if none of the LUNs are used any more. // That's where the prefix based ref count kicks in. If we only count the disks using exact match, we could log other disks out. func getDevicePrefixRefCount(mounter mount.Interface, deviceNamePrefix string) (int, error) { mps, err := mounter.List() if err != nil { return -1, err } // Find the number of references to the device. refCount := 0 for i := range mps { if strings.HasPrefix(mps[i].Device, deviceNamePrefix) { refCount++ } } return refCount, nil }