[patch 14/28] NFS: Close page_mkwrite() races

[Greg KH]

2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>


---
 fs/nfs/file.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -478,10 +478,10 @@ static int nfs_vm_page_mkwrite(struct vm
 
 	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 = {


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