Buyer Beware: A Major Change in NFS (in Rawhide) is about to happen

[Steve Dickson]

On 10/28/2009 03:05 PM, Roland McGrath wrote:
> It sounds like you are saying that there is no way to export the same
> host filesystems with the same client-perceived names under v4 as was
> being done before under v[23].  Is that really true?
With Pre-F12 servers... Yeah... 

The V4 protocol requires a 'pseudo root' to be defined. Other servers simply 
make '/' the pseudo root which allows all exports just to work with all versions.
The Linux server have the feature of being able to define the pseudo root with 
the use of the 'fsid=0' export option. A feature none of the other servers 
have. 

Unfortunately, there was no forethought as to what happens when a
pseudo root is not defined, until recently... Patches in both the
F-12 kernel and rpc.mountd now dynamically allocate a pseudo root
when one is not defined... Basically meaning '/' becomes the pseudo 
root when there is no fsid=0 export option.

> 
> My old /etc/exports is:
> 
> /mirror                        *(ro,insecure,sync,mp,all_squash)
> 
> So clients mount server:/mirror to see my /mirror directory's contents.
> No other /foo directory is exported or visible at all to clients, and
> that's how it should stay.
> 
> How do I get the same results for v4 clients?
Use a F-12 server or added the '/ *(ro,fsid=0)' export entry like:

/                              *(ro,fsid=0)
/mirror                        *(ro,insecure,sync,mp,all_squash)


steved.-