cifs: Fix xid leak in cifs_copy_file_range()

If the file is used by swap, before return -EOPNOTSUPP, should
free the xid, otherwise, the xid will be leaked.

Fixes: 4e8aea30 ("smb3: enable swap on SMB3 mounts")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsfs.c

@@ -1302,8 +1302,11 @@ static ssize_t cifs_copy_file_range(struct file *src_file, loff_t off,
 	ssize_t rc;
 	struct cifsFileInfo *cfile = dst_file->private_data;
 
-	if (cfile->swapfile)
-		return -EOPNOTSUPP;
+	if (cfile->swapfile) {
+		rc = -EOPNOTSUPP;
+		free_xid(xid);
+		return rc;
+	}
 
 	rc = cifs_file_copychunk_range(xid, src_file, off, dst_file, destoff,
 					len, flags);