Garrett Wollman <woll...@csail.mit.edu> wrote:
> Actually, it is quite well known (just apparently not by the author of
> that document). The fsid is used to generate NFS file handles. It's
> supposed to be random and unique per file server. (I think also it
> was supposed to be hard to guess as well, but the original NFS protocol
> didn't provide the sort of security guarantees that would make that
> property useful.)
The filesystem ID is not supposed to be randon but just unique for each
filesystem on a machine.
It cannot be random as it needs to survive a reboot.
A NFS filehandle in total is indeed de-facto random. It is the combination of
the filesystem IS, the inode number and the file generation number that is
incremented each time, the file association is changed, e.g. by a unlink()
operation.
BTW: to make the NFS file handle "random", the initial file generation number
is randomized, to prevent people from being able to guess a NFS file handle.
Jörg
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EMail:jo...@schily.net (home) Jörg Schilling D-13353 Berlin
joerg.schill...@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
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