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.
*** This bug has been marked as a duplicate of 209964 ***