From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Fri, 24 Apr 2009 21:32:22 +0000 (-0400)
Subject: NFS: Close page_mkwrite() races
X-Git-Tag: v2.6.29.4~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5da3b37d5eb68af30eb9e8bb553bed8c616024eb;p=thirdparty%2Fkernel%2Fstable.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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index f4a5bbbed14f8..523e7e0218055 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -481,10 +481,10 @@ 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 = {