Linux 'MountInfoTable' entries not sorted as expected

Many places in the codebase assume that the mountinfo table is sorted according to the order: parent mount point < child mount point.

However, in some cases this may not be true if (for example), a parent mount point (say /) is remounted to add some extra flags to it. When this happens, the remounted file system will appear in the mount table at the point where it was remounted.

We actually encountered this problem in the wild for the case of / being remounted after /run was mounted – causing problems in the NvidiaVolume which assumes the parent < child ordering.