Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755989Ab1CBIZE (ORCPT ); Wed, 2 Mar 2011 03:25:04 -0500 Received: from mail-ww0-f42.google.com ([74.125.82.42]:54257 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755922Ab1CBIZA (ORCPT ); Wed, 2 Mar 2011 03:25:00 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; b=lw+w5IpPd7dLxKVy6tg4UAYRtWP8rN3c3LIp0dQ2a2rK8sVcf5umh+KXI86DLQjmoW 2zjb1901mSdI+zenaZSD/1ScTO8w5kXDXu8pUoEQ52fQN04snAW7RR8mNrtxcNNEH2EE 1tRrNPW/RxKXLhj+VCScr04GnHw0YFQdHXhwM= Message-ID: <4D6DFDAA.3060006@gmail.com> Date: Wed, 02 Mar 2011 09:19:54 +0100 From: Marco Stornelli User-Agent: Mozilla/5.0 (X11; U; Linux i686; it; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Thunderbird/3.0.11 MIME-Version: 1.0 To: "Ted Ts'o" , Christoph Hellwig , Linux Kernel , cluster-devel@redhat.com, Linux FS Devel , linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, xfs@oss.sgi.com Subject: Re: [PATCH] Check for immutable flag in fallocate path References: <4D6221B8.9040303@gmail.com> <20110221124635.GA5525@infradead.org> <20110227224940.GL2924@thunk.org> In-Reply-To: <20110227224940.GL2924@thunk.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1556 Lines: 35 Il 27/02/2011 23:49, Ted Ts'o ha scritto: > On Mon, Feb 21, 2011 at 05:50:21PM +0100, Marco Stornelli wrote: >> 2011/2/21 Christoph Hellwig : >>> On Mon, Feb 21, 2011 at 09:26:32AM +0100, Marco Stornelli wrote: >>>> From: Marco Stornelli >>>> >>>> All fs must check for the immutable flag in their fallocate callback. >>>> It's possible to have a race condition in this scenario: an application >>>> open a file in read/write and it does something, meanwhile root set the >>>> immutable flag on the file, the application at that point can call >>>> fallocate with success. Only Ocfs2 check for the immutable flag at the >>>> moment. >>> >>> Please add the check in fs/open.c:do_fallocate() so that it covers all >>> filesystems. >>> >>> >> >> The check should be done after the fs got the inode mutex lock. > > Why? None of the other places which check the IMMUTABLE flag do so I add to my previous response an other point: IMHO each fs should check for it because after the inclusion of punch hole patch, the fs can/cannot check for the append-only flag. So XFS (it supports the "unreserve") should check even for append. I think we don't want to allow this operation for an append-only file, isn't it? About this point I'll update and resend my patch. Marco -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/