2.2.1.3.1 FileId Generation
64-bit file identifiers (FileIds) are generated on SMB servers. The generation of FileIds MUST satisfy the following constraints:
The FileId MUST be a 64-bit opaque value.
The FileId MUST be unique for a file on a given object store.<14>
The FileId for a file MUST persist for the lifetime of a file on a given object store. A FileId MUST NOT be changed when a file is renamed. When the file is deleted, the FileId MAY be reused.
All possible values for FileId are valid.