ceph: fix atomic_open snapdir

ceph_handle_snapdir() checks ceph_mdsc_do_request()'s return value
and creates snapdir inode if it's -ENOENT

Signed-off-by: Yan, Zheng <zyan@redhat.com>

fs/ceph/file.c

@@ -275,10 +275,10 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 	err = ceph_mdsc_do_request(mdsc,
 				   (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
 				   req);
+	err = ceph_handle_snapdir(req, dentry, err);
 	if (err)
 		goto out_req;
 
-	err = ceph_handle_snapdir(req, dentry, err);
 	if (err == 0 && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
 		err = ceph_handle_notrace_create(dir, dentry);