[pnfs] Layoutreturn Implementation

[Iyer, Rahul]

Yeah, probably true, but what if LAYOUTRETURN does fail? clear_inode()
returns nothing (void clear_inode()), so there's no way to signal an
error anyways! Besides, going  by the comment for the clear_inode()
function...
<snip>
/**
 * clear_inode - clear an inode
 * @inode: inode to clear
 *
 * This is called by the filesystem to tell us
 * that the inode is no longer useful. We just
 * terminate it with extreme prejudice.
 */
void clear_inode(struct inode *inode)
</snip>

There's not much to be gained from being synchronous. It seems to me
that doing a LAYOUTRETURN as a "best effort" seems reasonable...
Regards
Rahul


-----Original Message-----
From: Dean Hildebrand [mailto:dhildebz at eecs.umich.edu] 
Sent: Thursday, July 20, 2006 1:52 PM
To: Iyer, Rahul
Cc: pnfs at linux-nfs.org
Subject: Re: [pnfs] Layoutreturn Implementation

I think it has to be sync since we can't remove the inode until it
completes successfully.
Dean

Iyer, Rahul wrote:
> Hi,
> Currently, free_layout() is being called from only one functioon: 
> nfs4_clear_inode(). nfs4_clear_inode() is the .clear_inode pointer of 
> super_operations. The .clear_inode pointer is called by clear_inode().
> This is called mainly to remove the in memory inode reference.
>  
> The function that I spoke about, wwhich makes the LAYOUTRETURN rpc is 
> pnfs_return_layout(). This function is, however called nowhere. All 
> that needs to be done on the client is to call pnfs_return_layout() in

> nfs4_clear_inode().
> So, I presume it's fairly simple. However, I had a question:
> nfs4_proc_pnfs_layoutreturn() makes a call to rpc_call_sync(). Should 
> LAYOUTRETURN be a synchronous RPC? Is it better asynchronous? Do we
care?
>  
> Thanks
> Rahul
>  
>  
> ----------------------------------------------------------------------
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>
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--
Dean Hildebrand
Ph.D. Candidate
University of Michigan