From owner-freebsd-geom@FreeBSD.ORG Thu Jul 10 13:55:42 2008 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 82605106566B for ; Thu, 10 Jul 2008 13:55:42 +0000 (UTC) (envelope-from tapan.list@gmail.com) Received: from qb-out-0506.google.com (qb-out-0506.google.com [72.14.204.231]) by mx1.freebsd.org (Postfix) with ESMTP id 3D60F8FC1E for ; Thu, 10 Jul 2008 13:55:42 +0000 (UTC) (envelope-from tapan.list@gmail.com) Received: by qb-out-0506.google.com with SMTP id q12so7388737qba.13 for ; Thu, 10 Jul 2008 06:55:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type:references; bh=inHYr0sHq9nj2kF2vYG1/WvoD0Wwr0jcSSFdBofyiTE=; b=KtLT01slrFZKn3izIKp+RyXC9QCEmbm69DjCVUUbNYFXn6dz06eNiSNpxPXzsgbMGQ QAoHVtUcB5Lf4a9NCts59EzYBYLdJ4AcbbGWceLqwrHhM5wxkZGVb1dYkXdrYEnibarH x2qZsW5xpAswwMyOX/fPxcPKAk4cGtdSQSIzE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:references; b=Yc1bJV3/MNhc8fVSnwlMHVNfsXi2RrGtKhHycxeKmaT7eeG0lq7qhr+jAiJLvojqdd fo4hCpLg3o9R3Yiiz3u4uhnw+L+aemFGymQxvn/0869WUVKaIVpm5fIAIiN2nqneVQ3L VEWIncFLF/zmPpFwOWAuNzGY0cuVKU0BuC6qU= Received: by 10.102.218.6 with SMTP id q6mr2786239mug.127.1215698140146; Thu, 10 Jul 2008 06:55:40 -0700 (PDT) Received: by 10.103.227.19 with HTTP; Thu, 10 Jul 2008 06:55:40 -0700 (PDT) Message-ID: <482257ad0807100655u1a5c660awfad05564e40e9a95@mail.gmail.com> Date: Thu, 10 Jul 2008 19:25:40 +0530 From: "Tapan Chaudhari" To: freebsd-geom@freebsd.org In-Reply-To: <200807102309.03191.mark@legios.org> MIME-Version: 1.0 References: <482257ad0807100541s2d2c3d1eo6cd57c3a1bc338d1@mail.gmail.com> <200807102309.03191.mark@legios.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Re: Can GEOM be used to intercept the I/o calls to an existing mounted device? X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Jul 2008 13:55:42 -0000 Thanks Mark, but unmounting will anyways work. But the problem here will be, a new device "/dev/mirror/gm0" and "/dev/mirror/gm0s1" will be created after :- #gmirror label -v -n -b round-robin gm0 /dev/md0 #gmirror load #gmirror configure -a gm0 and "/dev/md0s1" gets deleted. Now I will have to mount the new device "/dev/mirror/gm0s1" to get my original contents. Can't I do it on the fly while the device is already mounted? I just want that all the calls going to the device "/dev/md0s1" first come to me and then it goes to the original device. In short intercepting the i/o calls. Is there some way I can achieve this? Thanks, On Thu, Jul 10, 2008 at 6:39 PM, Mark Gladman wrote: > On Thursday 10 July 2008 22:41:25 Tapan Chaudhari wrote: > > Hi All, > > I am a newbie to FreeBSD and GEOM. I wanted to intercept the i/o > calls > > going to a particular mounted device by writing some driver. > > I came across geom and thought it might work. I tried to create a new > > device, mount it and then tried using gmirror to mirror the device :- > > > > #dd if=/dev/zero of=file1 bs=1M count=10 > > #dd if=/dev/zero of=file2 bs=1M count=10 > > #mdconfig -f file1 > > #mdconfig -f file2 > > #fdisk -B /dev/mirror/md0 > > #newfs /dev/mirror/md0s1 > > #mkdir /mnt/mirror0 > > #mount /dev/mirror/md0s1 /mnt/mirror0/ > > > > #gmirror label -v -n -b round-robin gm0 /dev/md0 > > gmirror: Can't store metadata on /dev/md0: Operation not permitted. > > > > It gave me this error "gmirror: Can't store metadata on /dev/md0: > Operation > > not permitted." > > > > Am I doing something wrong? Or GEOM does not permit me intercept the i/o > > calls? If not geom, is there any other mechanism by which I can achieve > it? > > > > > > Thanks, > > --Tapan. > > _______________________________________________ > > freebsd-geom@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-geom > > To unsubscribe, send any mail to "freebsd-geom-unsubscribe@freebsd.org" > > Hey, > > You're attempting to set up gmirror on a mounted device. > Unmount /dev/mirror/md0s1 then retry the gmirror command and it should > work. > > Cheers! > Mark >