objects with SF_IMMUTABLE, SF_APPEND, or SF_NOUNLINK.
* Document that non-superusers cannot set or clear any SF_* flag
(setting fails with EPERM, clearing is silently ignored).
* Document that superusers cannot change any flag if one of
SF_IMMUTABLE, SF_APPEND, SF_NOUNLINK is set and securelevel is
greater than 0.
* Document SF_SNAPSHOT and note that it is maintained by the
system and is, for this reason, impossible to set to clear by
any user.
PR: docs/33877
Submitted by: harti
Help by: George Marsellis <gam9478@njit.edu>
MFC after: 1 week