Re: nfs exporting my stacked fs

[Andrew Sharp <andy@ccpu.com>]

On Thu, May 29, 2003 at 09:05:37AM +1000, Neil Brown wrote:
> On Wednesday May 28, andy@ccpu.com wrote:
> > I could use some help getting my stacked (I guess that's the term d' jour)
> > file system to be nfs exported/mounted.  From reading the code, it seems
> > that my file system either has to require a device, it doesn't, or it
> > has to have some sort of FSID (the call to nfsctl_export() is failing),
> > only I can't seem to figure out how to accomplish that.  I tried to go
> > through the mountd source, but came up empty.  What did I miss?
> 
> If your filesystem isn't device based (which seems likely for a
> stacked filesystem), the nfsd cannot use the device number as a short,
> fixed length identifier for the filesystem, which it needs for storing
> in the filehandle.  So, you need to provide one.
> This is done in the /etc/exportss file with the fsid= option.
> e.g.
> 
>  /my/file/system myclient(rw,no_root_squash,sync,fsid=27)

Thanks for that info, I was unaware of that option.  Soooo, this brings
up some other questions for me.

What is the relation between the fsid option mentioned above and the
fsid returned by statfs op?  Which I discovered shortly after sending my
first email.  Should they match?  The i_dev is apparently used on device
datasets for the filehandle, so do all datasets with the same i_dev
somehow guarantee that i_dev/inode # 'filehandles' are somehow unique?

a