[$] listmount() and statmount()

Years ago, the list of mounted filesystems on a Unix or Linux machine wasrelatively short and static. Adding a filesystem, which typically involvedbuying a new drive, happened rarely. In contrast, contemporary systemswith a large number of containers can have a long and dynamic list ofmounted filesystems. As was discussed atthe 2023 LSFMM+BPF Summit, the Linuxkernel's mechanism for providing information about mounted filesystems hasnot kept up with this change, leading to system-management headaches. Now,two new system calls proposedby Miklos Szeredi look set to provide some much-needed pain relief.