Re: Linux 3.11-rc2

["Myklebust, Trond" <Trond.Myklebust@netapp.com>]

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On Mon, 2013-07-22 at 21:17 -0400, Trond Myklebust wrote:
> On Tue, 2013-07-23 at 03:04 +0200, rydberg@euromail.se wrote:
> > Hi Trond, Linus,
> > 
> > On Sun, Jul 21, 2013 at 12:53:10PM -0700, Linus Torvalds wrote:
> > > So it's been another week, and -rc2 is out there.
> > 
> > This one happens to break nfs in a rather blunt-instrument fashion -
> > creating files on a nfs4 partition [1] no longer works. Bisection
> > yields this commit as the culprit:
> > 
> > commit b4a2cf76ab7c08628c62b2062dacefa496b59dfd
> > Author: Trond Myklebust <Trond.Myklebust@netapp.com>
> > Date:   Wed Jul 17 16:43:16 2013 -0400
> > 
> >     NFSv4: Fix a regression against the FreeBSD server
> >     
> >     Technically, the Linux client is allowed by the NFSv4 spec to send
> >     3 word bitmaps as part of an OPEN request. However, this causes the
> >     current FreeBSD server to return NFS4ERR_ATTRNOTSUPP errors.
> >     
> >     Fix the regression by making the Linux client use a 2 word bitmap unless
> >     doing NFSv4.2 with labeled NFS.
> >     
> >     Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> > 
> > Reverting the patch returns things to normal.
> 
> - Can you please provide me with a binary tcpdump or wireshark dump that
> demonstrates the problem?
> 
> - What server is this?

OK. With Andre's help, I think we've root caused the problem. Can you
please confirm that the attached patch also solves the issue for you?

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com

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From 1f84e4f9ef9fc4ff502c112df049dfa6f656f4e0 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Tue, 23 Jul 2013 12:53:39 -0400
Subject: [PATCH] NFSv4: Fix brainfart in attribute length calculation

The calculation of the attribute length was 4 bytes off.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Andre Heider <a.heider@gmail.com>
---
 fs/nfs/nfs4xdr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index c74d616..3850b01 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1118,11 +1118,11 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 				len, ((char *)p - (char *)q) + 4);
 		BUG();
 	}
-	len = (char *)p - (char *)q - (bmval_len << 2);
 	*q++ = htonl(bmval0);
 	*q++ = htonl(bmval1);
 	if (bmval_len == 3)
 		*q++ = htonl(bmval2);
+	len = (char *)p - (char *)(q + 1);
 	*q = htonl(len);
 
 /* out: */
-- 
1.8.3.1