// utility to mount a disk based filesystem
func diskSetUp(manager diskManager, disk iscsiDisk, volPath string, mounter mount.Interface) error {
globalPDPath := manager.MakeGlobalPDName(disk)
// TODO: handle failed mounts here.
mountpoint, err := mounter.IsMountPoint(volPath)
if err != nil && !os.IsNotExist(err) {
glog.Errorf("cannot validate mountpoint: %s", volPath)
return err
}
if mountpoint {
return nil
}
if err := manager.AttachDisk(disk); err != nil {
glog.Errorf("failed to attach disk")
return err
}
if err := os.MkdirAll(volPath, 0750); err != nil {
glog.Errorf("failed to mkdir:%s", volPath)
return err
}
// Perform a bind mount to the full path to allow duplicate mounts of the same disk.
options := []string{"bind"}
if disk.readOnly {
options = append(options, "ro")
}
err = mounter.Mount(globalPDPath, volPath, "", options)
if err != nil {
glog.Errorf("failed to bind mount:%s", globalPDPath)
return err
}
return 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
}
// utility to tear down a disk based filesystem
func diskTearDown(manager diskManager, disk iscsiDisk, volPath string, mounter mount.Interface) error {
mountpoint, err := mounter.IsMountPoint(volPath)
if err != nil {
glog.Errorf("cannot validate mountpoint %s", volPath)
return err
}
if !mountpoint {
return os.Remove(volPath)
}
refs, err := mount.GetMountRefs(mounter, volPath)
if err != nil {
glog.Errorf("failed to get reference count %s", volPath)
return err
}
if err := mounter.Unmount(volPath); err != nil {
glog.Errorf("failed to unmount %s", volPath)
return err
}
// If len(refs) is 1, then all bind mounts have been removed, and the
// remaining reference is the global mount. It is safe to detach.
if len(refs) == 1 {
mntPath := refs[0]
if err := manager.DetachDisk(disk, mntPath); err != nil {
glog.Errorf("failed to detach disk from %s", mntPath)
return err
}
}
mountpoint, mntErr := mounter.IsMountPoint(volPath)
if mntErr != nil {
glog.Errorf("isMountpoint check failed: %v", mntErr)
return err
}
if !mountpoint {
if err := os.Remove(volPath); err != nil {
return err
}
}
return nil
}