cifs: implement i_op->atomic_open()

Add an ->atomic_open implementation which replaces the atomic lookup+open+create
operation implemented via ->lookup and ->create operations.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Steve French <sfrench@samba.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index bcab12c..c0c2751a 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -777,6 +777,7 @@
 };
 const struct inode_operations cifs_dir_inode_ops = {
 	.create = cifs_create,
+	.atomic_open = cifs_atomic_open,
 	.lookup = cifs_lookup,
 	.getattr = cifs_getattr,
 	.unlink = cifs_unlink,