[3.11.y.z extended stable] Patch "nfsd4: fix xdr decoding of large non-write compounds" 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 xdr decoding of large non-write compounds

to the linux-3.11.y-queue branch of the 3.11.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-3.11.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 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ecf9e5980e6c592fdc35687b268751c9e093f11d Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields at redhat.com>
Date: Tue, 19 Nov 2013 17:32:43 -0500
Subject: nfsd4: fix xdr decoding of large non-write compounds

commit 365da4adebb1c012febf81019ad3dc5bb52e2a13 upstream.

This fixes a regression from 247500820ebd02ad87525db5d9b199e5b66f6636
"nfsd4: fix decoding of compounds across page boundaries".  The previous
code was correct: argp->pagelist is initialized in
nfs4svc_deocde_compoundargs to rqstp->rq_arg.pages, and is therefore a
pointer to the page *after* the page we are currently decoding.

The reason that patch nevertheless fixed a problem with decoding
compounds containing write was a bug in the write decoding introduced by
5a80a54d21c96590d013378d8c5f65f879451ab4 "nfsd4: reorganize write
decoding", after which write decoding no longer adhered to the rule that
argp->pagelist point to the next page.

Signed-off-by: J. Bruce Fields <bfields at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/nfsd/nfs4xdr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index c2a4701..b6dbc8d 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -141,8 +141,8 @@ xdr_error:					\

 static void next_decode_page(struct nfsd4_compoundargs *argp)
 {
-	argp->pagelist++;
 	argp->p = page_address(argp->pagelist[0]);
+	argp->pagelist++;
 	if (argp->pagelen < PAGE_SIZE) {
 		argp->end = argp->p + (argp->pagelen>>2);
 		argp->pagelen = 0;
@@ -1208,6 +1208,7 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
 		len -= pages * PAGE_SIZE;

 		argp->p = (__be32 *)page_address(argp->pagelist[0]);
+		argp->pagelist++;
 		argp->end = argp->p + XDR_QUADLEN(PAGE_SIZE);
 	}
 	argp->p += XDR_QUADLEN(len);
--
1.8.3.2