why can't you exportfs /dir and /dir/sub?

[Leendert van Doorn]

boyd at prl.dec.com (Boyd Roberts) writes:

#In article <1991Jun18.044122.16327 at thunder.mcrcim.mcgill.edu>, mouse at thunder.mcrcim.mcgill.edu (der Mouse) writes:
#> 
#> Well yes, that's the bug.  The question is, why couldn't they fix it?
#> 
#
#I guess the bug-fix would violate the stateless protocol :-)

Actually it wouldn't. It would only blur the functional division
between the mount daemon and the NFS daemon. All the NFS daemon has to
do is to enforce the restrictions set in the /etc/export file. It has
to check every NFSPROC_LOOKUP operation on "..". This isn't as
expensive as it appears:  the root-vnodes of the exported file systems
should be cached with a special flag, when a lookup is performed and the
current vnode has this bit set it should perform the access check.
But, as said before, this would break the functional division.

	Leendert


--
Leendert van Doorn 			   		<leendert at cs.vu.nl>
Vrije Universiteit / Dept. of Maths. & Comp. Sc.	+31 20 5485301
Amoeba project / De Boelelaan 1081A
1081 HV Amsterdam / The Netherlands