[pnfs] CVS: nfsv4

[Iyer, Rahul]

Using the rpc_clnt struct gets the a reference to the counter, but the
rpc shutdown code forcefully causes the task to exit with -EIO.
Unfortunately, having a referennce does not help.

Incidentally, returning of delegations is also done in a similar fashion
(async call followed by a wait for its completion)
Regards
Rahul


-----Original Message-----
From: William A.(Andy) Adamson [mailto:andros at citi.umich.edu] 
Sent: Tuesday, August 01, 2006 12:55 PM
To: Iyer, Rahul
Cc: Marc Eshel; Rahul Iyer (NetApp); pnfs at linux-nfs.org;
andros at citi.umich.edu
Subject: Re: [pnfs] CVS: nfsv4 

> Hi,
> I mean the inode freeing routines, not the free_layout () call. Here's

> the problem...
> The xdr encode routine takes the inode as part of the arguments. It 
> uses this to get the file handle for the PUTFH in the compound 
> containing the LAYOUTRETURN. I agree, we could get the file handle 
> earlier and then pass this down instead of the inode.
> 
> But the other problem is that we need the rpc_clnt struct too. This is

> also present in the inode. We could extract this also, but we wind up 
> in a race with umount. During umount, the rpc_shutdown_clients kills 
> all outstanding rpc_clnt structs.
> 
> So, here's my plan. I plan to make ir sort of async, but not exactly. 
> I will issue the rpc asynchronously, but wait for it to complete. 
> While this is not truly asynchronous, it avoids the races we have. It 
> however, is slightly better than synchronous because the user can now 
> interrupt it.

can't you hold a reference to the structures that you need while the
async rpc is in flight?

-->Andy

> Thanks
> Regards
> Rahul
> 
> 
> -----Original Message-----
> From: Marc Eshel [mailto:eshel at almaden.ibm.com]
> Sent: Tuesday, August 01, 2006 9:20 AM
> To: Iyer, Rahul
> Cc: Rahul Iyer (NetApp); pnfs at linux-nfs.org
> Subject: RE: [pnfs] CVS: nfsv4
> 
> What exactly is the problem? Can't you remove the pointer 
> current_layout from the inode (set it to NULL) and than you can either

> free it even before the async call or if you need it for some reason 
> free it in rpc_call_done ?
> I think that this call should be async.
> Marc.
> 
> pnfs-bounces at linux-nfs.org wrote on 07/31/2006 10:29:22 PM:
> 
> > PFA the patch for the following commit. 
> > Regards
> > Rahul
> > 
> > 
> > -----Original Message-----
> > From: Rahul Iyer (NetApp) [mailto:iyer at citi.umich.edu]
> > Sent: Monday, July 31, 2006 10:28 PM
> > To: pnfs at linux-nfs.org
> > Subject: [pnfs] CVS: nfsv4
> > 
> > CVSROOT:   /cvs
> > Module name:   nfsv4
> > Changes by:   iyer at citi.   2006/08/01 01:28:20
> > 
> > Modified files:
> >    cvs/pnfs/fs/nfs: nfs4proc.c
> > 
> > Log message:
> > Making LAYOUTRETURN synchronous. Having LAYOUTRETURN be asynchronous

> > causes race condition between LAYOUTRETURN and the inode freeing 
> > routines.
> > 
> > _______________________________________________
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> > [attachment "diff" deleted by Marc Eshel/Almaden/IBM] 
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