[3.8.y.z extended stable] Patch "nfsd4: fix xdr decoding of large non-write compounds" has been added to staging queue

[Kamal Mostafa]

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-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.14.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 38a9449db1a42731eb9c4da6856c879ef9fc5bbf 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>
[ kamal: backport to 3.8 (next_decode_page change is in read_buf) ]
Signed-off-by: Kamal Mostafa <kamal 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 859d145..3ed8550 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -162,8 +162,8 @@ static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)
 	 */
 	memcpy(p, argp->p, avail);
 	/* step to next page */
-	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;
@@ -1160,6 +1160,7 @@ 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