Bug 248599

As covered in Redhat bug 222138, multiple instances of a NFS mount only use the
options of the first mount. kernel.org bug, from the previously cited issue
covers this very unambiguously:

     http://bugzilla.kernel.org/show_bug.cgi?id=7612

...however this behavior should likely be revisited. From our own experiences
tripping across this and the time this went undiagnosed in issue 222138, clearly
this is far from the "principle of least surprise".

Opening this against RHEL5, since with autofs5's "-hosts" map, the problem could
become decidedly more painful since mounts become administratively
nondeterministic. While I question anyone using a -hosts map anywhere but a
casual desktop environment, there's enough other cases where this could (for
example) leave a daemon chroot'ed into a ro NFS mount actually ending up with a
rw mount.

At the very least, nfs (or further up the VFS stack) should detect this
condition and use the inherited mount options (rather than those provide) to
update the mount tab. Ideally, it should always defer to the "least
conservative" options, though there's enough ambiguous cases ('ro' trumps 'ro',
'nosuid' trumps 'suid' are obvious enough, things like attribute caching are
questionable) that this is likely impractical. While this would likely lead to
plenty of finger pointing at autofs still, at least the mtab would accurately
reflect reality.