[pnfs] CVS: nfsv4

[Marc Eshel]

pnfs-bounces at linux-nfs.org wrote on 12/26/2006 03:42:27 AM:

> Marc, there are a few problems with this.
> 
> 1. "nfsi->pnfs_layout_state |= NFS_INO_LAYOUT_FAILED;" happens 
> unconditionally,
> in all cases, including success. (I will submit a patch fixing that 
today)

Yes, I guess I had to much Eggnog.
 
> 2. I understand marking the client's nfs_file with such a flag when the 
server
> returns a permanent error such as NFS4ERR_LAYOUTUNAVAILABLE but in 
> other cases,
> when the error is transient we must have a mechanism to clear the state, 
e.g.
> put a timestamp on the file after which you'll start asking for layouts 
again
> (e.g. in the NFS4ERR_LAYOUTTRYLATER case).  I summary, the server's 
error code
> must be analyzed by the client to determine what to do.  IMO, we 
> should consider
> reverting what you did in this submit until we have finer grained 
> error handling
> for layoutget.

Yes, error recovery needs much more work. I was just trying to fix a 
specific failure that I observed while the server refused to give layout 
and the client kept asking for it on each IO. 

> 3. I noticed that when virtual_update_layout returns an error on theread 
path
> the error is returned to the application as EIO.  This is wrong as the 
client
> should fall back to doing NFSv4 I/O when it couldn't get a layout. 
> I'm working
> on a patch for that too.

I though I already fixed the read path to do just that maybe I missed a 
place. The write path definitely needs more work.

> 
> Benny
> 
> Marc Eshel (IBM) wrote:
> > CVSROOT:   /cvs
> > Module name:   nfsv4
> > Changes by:   eshel at citi.   2006/12/24 19:01:59
> > 
> > Modified files:
> >    cvs/pnfs/fs/nfs: inode.c pnfs.c 
> > 
> > Log message:
> > If for some reason the server does not return a layout the client 
> keep asking
> > on each read. Remember that get layout failed and don't request it 
again.
> > 
> > Index: inode.c
> > ===================================================================
> > RCS file: /cvs/nfsv4/cvs/pnfs/fs/nfs/inode.c,v
> > retrieving revision 1.17
> > diff -u -r1.17 inode.c
> > --- inode.c   18 Dec 2006 17:18:43 -0000   1.17
> > +++ inode.c   24 Dec 2006 23:54:04 -0000
> > @@ -1084,6 +1084,7 @@
> > #endif
> > #ifdef CONFIG_NFS_V4 /* XXX CONFIG_PNFS */
> > nfsi->nfs4_acl = NULL;
> > +   nfsi->pnfs_layout_state = 0;
> > nfsi->current_layout = NULL;
> > nfsi->layoutcommit_ctx = NULL;
> > #endif /* CONFIG_NFS_V4 */
> > Index: pnfs.c
> > ===================================================================
> > RCS file: /cvs/nfsv4/cvs/pnfs/fs/nfs/pnfs.c,v
> > retrieving revision 1.50
> > diff -u -r1.50 pnfs.c
> > --- pnfs.c   14 Dec 2006 10:47:40 -0000   1.50
> > +++ pnfs.c   24 Dec 2006 23:54:05 -0000
> > @@ -436,6 +436,11 @@
> > }
> > 
> > res.layout.buf = NULL;
> > +
> > +        /* if get layout already failed once goto out */
> > +        if (nfsi->pnfs_layout_state & NFS_INO_LAYOUT_FAILED)
> > +      goto out;
> > +
> > if ((result = get_layout(ino, ctx, count, pos, iomode, &arg, &res))) {
> > printk("\n%s: ERROR retrieving layout %d\n",__FUNCTION__,result);
> > result =  -EIO;
> > @@ -468,10 +473,15 @@
> > 
> > result = 0;
> > out:
> > +
> > +        /* remember that get layout failed and don't try again */
> > +        nfsi->pnfs_layout_state |= NFS_INO_LAYOUT_FAILED;
> > +
> > /* res.layout.buf kalloc'ed by the xdr decoder? */
> > if (res.layout.buf)
> > kfree(res.layout.buf);
> > -   dprintk("%s end (err:%d)\n",__FUNCTION__,result);
> > +   dprintk("%s end (err:%d) state %d\n",
> > +      __FUNCTION__,result,nfsi->pnfs_layout_state);
> > return result;
> > }
> > 
> > _______________________________________________
> > pNFS mailing list
> > pNFS at linux-nfs.org
> > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
> 
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