It is possible to create filesystems with mountpoints beneath that of other filesystems. In
this scenario, the parent filesystems are mounted before children and vice versa. The following
cases should be considered when using nested mountpoints:
If the mountpoint doesn't exist, one will be created, owned by root and mode 0755. This
mountpoint may or may not be torn down when the filesystem is renamed, destroyed, or moved,
depending on circumstances. To be safe, mountpoints should be created within the parent share before
creating the child filesystem.
If the parent directory is read-only, and the mountpoint doesn't exist, the filesystem mount
will fail. This can happen synchronously when creating a filesystem, but can also happen
asynchronously when making a large-scale change, such as renaming filesystems with inherited
When renaming a filesystem or changing its mountpoint, all children beneath the current
mountpoint as well as the new mountpoint (if different) will be unmounted and remounted after
applying the change. This will interrupt any data services currently accessing the share.
Support for automatically traversing nested mountpoints depends on protocol, as outlined