#### Storage

* [stable] Mount options

  * The ability to specify mount options for volumes is moved from beta to stable.

  * A new `MountOptions` field in the `PersistentVolume` spec is available to specify mount options. This field replaces an annotation.

  * A new `MountOptions` field in the `StorageClass` spec allows configuration of mount options for dynamically provisioned volumes.

* fix mount unmount failure for a Windows pod ([#63272](https://github.com/kubernetes/kubernetes/pull/63272), [@andyzhangx](https://github.com/andyzhangx))
* Fix concurrent map access panic ([#65327](https://github.com/kubernetes/kubernetes/pull/65327), [@dashpole](https://github.com/dashpole))
    * Don't watch .mount cgroups to reduce number of inotify watches

* Fix stackdriver metrics for node memory using wrong metric type ([#63535](https://github.co/kubernetes/kubernetes/pull/63535), [@serathius](https://github.com/serathius))
* fix mount unmount failure for a Windows pod ([#63272](https://github.com/kubernetes/kubernetes/pull/63272), [@andyzhangx](https://github.com/andyzhangx))

#### General Fixes and Reliability

* Because some plugins mount volume on sub-directory of volume path, we need to distinguish between volume path and mount path to fix issue in reconstruction. ([#74653](https://github.com/kubernetes/kubernetes/pull/74653), [@cofyc](https://github.com/cofyc))

in containers are now `rslave` on Linux by default. To make this default work in all Linux environments the entire mount tree should be marked as shareable, e.g. via `mount --make-rshared /`. All Linux distributions that use systemd already have the root directory mounted as rshared and hence they need not do anything. In Linux environments without systemd we recommend running `mount --make-rshared /` during boot before docker is started, ([@jsafrane](https://github.com/jsafrane))

##...

* Local volume source paths that are directories and not mount points fail to unmount.  A fix is in process ([#48331](https://github.com/kubernetes/kubernetes/issues/48331)).

- Fixed smb remount and unmount issues on Windows ([#73661](https://github.com/kubernetes/kubernetes/pull/73661), [@andyzhangx](https://github.com/andyzhangx), [#75087](https://github.com/kubernetes/kubernetes/pull/75087), [@andyzhangx](https://github.com/andyzhangx))

- On compatible systems, a mounter's Unmount implementation is changed to not return an error when the specified target can be detected as not a mount point. On Linux, the behavior of detecting a mount point depends on `umount` command is validated when the mounter is created. Additionally, mount point checks will be skipped in CleanupMountPoint/CleanupMountWithForce if the mounter's Unmount having the changed behavior of not returning error when target is not a...

* fix race condition issue for smb mount on windows ([#75371](https://github.com/kubernetes/kubernetes/pull/75371), [@andyzhangx](https://github.com/andyzhangx))
* fix smb unmount issue on Windows ([#75087](https://github.com/kubernetes/kubernetes/pull/75087), [@andyzhangx](https://github.com/andyzhangx))

* Fix issue when attempting to unmount a wrong vSphere volume ([#37413](https://github.com/kubernetes/kubernetes/pull/37413), [@BaluDontu](https://github.com/BaluDontu))

#### Other Notable Changes
* Implement bulk polling of volumes ([#41306](https://github.com/kubernetes/kubernetes/pull/41306), [@gnufied](https://github.com/gnufied))