From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7654C5CFE7 for ; Wed, 11 Jul 2018 15:52:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE2DF208E5 for ; Wed, 11 Jul 2018 15:52:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE2DF208E5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lwn.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389510AbeGKP5C (ORCPT ); Wed, 11 Jul 2018 11:57:02 -0400 Received: from ms.lwn.net ([45.79.88.28]:40396 "EHLO ms.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732411AbeGKP5B (ORCPT ); Wed, 11 Jul 2018 11:57:01 -0400 Received: from localhost.localdomain (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ms.lwn.net (Postfix) with ESMTPSA id E70217DA; Wed, 11 Jul 2018 15:52:02 +0000 (UTC) Date: Wed, 11 Jul 2018 09:51:59 -0600 From: Jonathan Corbet To: David Howells Cc: viro@zeniv.linux.org.uk, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 24/32] vfs: syscall: Add fsopen() to prepare for superblock creation [ver #9] Message-ID: <20180711095159.08e5435c@lwn.net> In-Reply-To: <153126264966.14533.3388004240803696769.stgit@warthog.procyon.org.uk> References: <153126248868.14533.9751473662727327569.stgit@warthog.procyon.org.uk> <153126264966.14533.3388004240803696769.stgit@warthog.procyon.org.uk> Organization: LWN.net X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 10 Jul 2018 23:44:09 +0100 David Howells wrote: > sfd = fsopen("ext4", FSOPEN_CLOEXEC); > write(sfd, "s /dev/sdb1"); // note I'm ignoring write's length arg > write(sfd, "o noatime"); > write(sfd, "o acl"); > write(sfd, "o user_attr"); > write(sfd, "o iversion"); > write(sfd, "o "); > write(sfd, "r /my/container"); // root inside the fs > write(sfd, "x create"); // create the superblock A minor detail but ... the "r" operation mentioned above is not actually implemented in this system call. jon