From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Tue, 12 May 2009 06:23:52 +0000 (+1000)
Subject: NFS: Close page_mkwrite() races
X-Git-Tag: v2.6.27.24~15
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=71cf4edb1d866d69773bce35f9761d1973b671c9;p=pandora-kernel.git

NFS: Close page_mkwrite() races

commit 7fdf523067666b0eaff330f362401ee50ce187c4 upstream

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.

See http://bugzilla.kernel.org/show_bug.cgi?id=12913

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index a7c9f7b3ac1b..4a57a0f9a2ac 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -478,10 +478,10 @@ 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 = {