Descriptions taken from mountd code (in nfs-utils/utils/mountd/cache.c).
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
* 1 - 4 byte user specified identifier
* 2 - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
* 3 - 4 byte device id, encoded for user-space, 4 byte inode number
+ * 4 - 4 byte inode number and 4 byte uuid
+ * 5 - 8 byte uuid
+ * 6 - 16 byte uuid
+ * 7 - 8 byte inode number and 16 byte uuid
*
* The fileid_type identified how the file within the filesystem is encoded.
* This is (will be) passed to, and set by, the underlying filesystem if it supports