[Unionfs] Anybody looking at NFS exporting a unionfs ?

[David P. Quigley]

It is worth nothing that this might not be a trivial implementation. In
the past to ensure that this functionality was correct we needed some
sort of persistent inode store. This may not be true anymore but if it
is then it isn't as simple as implementing 3 functions.

Dave

On Wed, 2007-09-05 at 11:07 -0400, David P. Quigley wrote:
> 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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> > 	
> > 
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> 
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