[Unionfs] Anybody looking at NFS exporting a unionfs ?

[David P. Quigley]

Well I figured out the cause with NFSv4 running the git tree of unionfs.
The answer is pretty simple

>From debug information:

echo 32767 >/proc/sys/sunrpc/nfs_debug
echo 32767 >/proc/sys/sunrpc/nfsd_debug

"exp_export: export of invalid fs type."

>From check_export in nfsd/export.c
389         if (!inode->i_sb->s_export_op) {
390                 dprintk("exp_export: export of invalid fs type.\n");
391                 return -EINVAL;
392         }

This means that the unionfs superblock does not define the
export_operations op vector. Implementing this should enable unionfs 2.1
to be exported across the network atleast on NFSv4. I haven't tested
this with v3.

On Wed, 2007-09-05 at 10:47 -0400, Miner, Jonathan W (CSC) (US SSA)
wrote:
> Hi -
>  
> It's been a while, but I think this used to work.  I had a Linux server setup to do HSM with a unionFS made up of slow, medium, and fast storage.  The unionFS was exported to Linux and Solaris clients.  Behind the scenes, I had scripts which migrated files which were not accessed to slower storage.  All proof-of-concept, but I recall it worked.
>  
> I was using unionFS 1.1.2 and kernel 2.6.14-1.1656_FC4smp, I found my notes, and have attached them to this email
> 
> 	-----Original Message----- 
> 	From: unionfs-bounces at fsl.cs.sunysb.edu on behalf of Jesse I Pollard 
> 	Sent: Wed 09/05/2007 10:19 AM 
> 	To: unionfs at fsl.cs.sunysb.edu 
> 	Cc: 
> 	Subject: [Unionfs] Anybody looking at NFS exporting a unionfs ?
> 	
> 	
> 
> 	Right now I'm tracing through nfsd to understand why it doesn't work.
> 	
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