From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: "Write once only but read many" filesystem Date: Sat, 22 Mar 2008 17:59:06 +0100 Message-ID: <20080322165906.GC19347@logfs.org> References: <804dabb00803140917o2abebd2dh12c77b21a48094c4@mail.gmail.com> <20080314232403.GI3542@webber.adilger.int> <47E48D84.7070701@gmail.com> <20080322102331.GA19347@logfs.org> <804dabb00803220752h670757d8o9c1b7fa3696467bc@mail.gmail.com> <20080322150626.GB19347@logfs.org> <804dabb00803220855q1aa41fc7mc30c7ce7951fe98@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kernelnewbies , linux-fsdevel@vger.kernel.org, ext3-users@redhat.com To: Peter Teoh Return-path: Received: from lazybastard.de ([212.112.238.170]:58729 "EHLO longford.logfs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753231AbYCVQ7Y (ORCPT ); Sat, 22 Mar 2008 12:59:24 -0400 Content-Disposition: inline In-Reply-To: <804dabb00803220855q1aa41fc7mc30c7ce7951fe98@mail.gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Sat, 22 March 2008 23:55:53 +0800, Peter Teoh wrote: >=20 > > Or do you want individual files/directories to be immutable - cha= ttr? >=20 > chattr is not good enough, as root can still modify it. So if > current feature is not there, then some small development may be > needed. >=20 > > And in either case, what problem do you want to solve with a read-= only filesystem? >=20 > Simple: i want to record down everything that a user does, or a > database does, or any applications running - just record down its > state permanently securely into the filesystem, knowing that for sure= , > there is not way to modify the data, short of recreating the > filesystem again. Sound logical? Or is there any loophole in thi= s > concept? The loophole is called root. In a normal setup, root can do anything, including writing directly to the device your filesystem resides in, writing to kernel memory, etc. It may be rather inconvenient to change a filesystem by writing to the block device, but far from impossible. If you want to make such change= s impossible, you are facing an uphill battle that I personally don't car= e about. And if inconvenience is good enough, wouldn't chattr be sufficiently inconvenient? J=C3=B6rn --=20 Victory in war is not repetitious. -- Sun Tzu -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html