min/max uid for snapshot creation
On shared systems like shared hosting it might be useful to prevent regular users from creating snapshots on CephFS.
A rogue user might create thousands of snapshots using a lot of space or even be a DoS for a MDS.
A min_uid/max_uid setting for the MDS or mount parameter for the kernel module might be useful to limit the creation of snapshots.
mds: Make min/max UID configurable for who is allowed to create a snapshot
This way administrators can configure which UIDs are allowed to create
snapshots on CephFS.
In certain situations it might be desirable that regular users are not allowed
to create snapshots. For example on shared hosting environments.