Re: [patch] mm: close page_mkwrite races (try 3)

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Wed, 2009-04-29 at 08:27 -0700, Andrew Morton wrote:
> I don't know what the "NFS 3 liner" is, but I trust you'll take care of
> it.

It's this one. I can send it on to Linus as soon as Nick's stuff is
upstream unless you'd prefer to fold it in with his patch.

Cheers
  Trond
---------------------------------------------------------------------
>From f0258852dcb43c748854d2ee550c9c270bb25f21 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Fri, 24 Apr 2009 17:32:22 -0400
Subject: [PATCH] NFS: Close page_mkwrite() races

Follow up to Nick Piggin's patches to ensure that nfs_vm_page_mkwrite
returns with the page lock held, and sets the VM_FAULT_LOCKED flag.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/file.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 5a97bcf..ec7e27d 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -517,10 +517,10 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 	ret = nfs_updatepage(filp, page, 0, pagelen);
 out_unlock:
+	if (!ret)
+		return VM_FAULT_LOCKED;
 	unlock_page(page);
-	if (ret)
-		ret = VM_FAULT_SIGBUS;
-	return ret;
+	return VM_FAULT_SIGBUS;
 }
 
 static struct vm_operations_struct nfs_file_vm_ops = {
-- 
1.6.0.6