[ 3.5.y.z extended stable ] Patch "nfsd4: fix decoding of compounds across page boundaries" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    nfsd4: fix decoding of compounds across page boundaries

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 9bbb76f6d9ed15cb2f1a69836b0cca7cd72d0f19 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields at redhat.com>
Date: Fri, 21 Jun 2013 11:48:11 -0400
Subject: [PATCH] nfsd4: fix decoding of compounds across page boundaries

commit 247500820ebd02ad87525db5d9b199e5b66f6636 upstream.

A freebsd NFSv4.0 client was getting rare IO errors expanding a tarball.
A network trace showed the server returning BAD_XDR on the final getattr
of a getattr+write+getattr compound.  The final getattr started on a
page boundary.

I believe the Linux client ignores errors on the post-write getattr, and
that that's why we haven't seen this before.

Reported-by: Rick Macklem <rmacklem at uoguelph.ca>
Signed-off-by: J. Bruce Fields <bfields at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/nfsd/nfs4xdr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b2ae2da..65ed9bf 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -161,8 +161,8 @@ static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)
 	 */
 	memcpy(p, argp->p, avail);
 	/* step to next page */
-	argp->p = page_address(argp->pagelist[0]);
 	argp->pagelist++;
+	argp->p = page_address(argp->pagelist[0]);
 	if (argp->pagelen < PAGE_SIZE) {
 		argp->end = argp->p + (argp->pagelen>>2);
 		argp->pagelen = 0;
--
1.8.1.2