From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David Guyon Martin" Subject: device mapper integrated loops - and one more year ! Date: Thu, 5 Oct 2006 16:26:54 +0200 Message-ID: <2c53b31c0610050726o47e6784en417de93b98d15e50@mail.gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0479858206==" Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids --===============0479858206== Content-Type: multipart/alternative; boundary="----=_Part_11298_30099163.1160058414050" ------=_Part_11298_30099163.1160058414050 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Hello, Do you think dm could have a loop target instead of seting loops with losetup ? We allready have dm-crypt for the encryption stage of a "losetup -e ", dm replaces losetup when source is a device but I understand that we still need losetup if the source is a regular file. Our problem is that we will need to map a great number of files, as if they were PVs of a VG. Linux kernel can have up to 255 loops but we will reach this limit. The idea is to embed to loop itself in a device mapper add-on like dm-crypt, so we won't use any /dev/loop* . Do you think this is stupid or is there some possility out there ? (we would like to have some advice before starting any project in this direction) Thank you, David G.M. PS: Anniversary of this post, one year ago ! http://www.redhat.com/archives/dm-devel/2005-October/msg00031.html ------=_Part_11298_30099163.1160058414050 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Hello,

Do you think dm could have a loop target instead of seting loops with losetup ?
We allready have dm-crypt for the encryption stage of a "losetup -e <crypt>", dm replaces losetup when source is a device but I understand that we still need losetup if the source is a regular file.
Our problem is that we will need to map a great number of files, as if they were PVs of a VG. Linux kernel can have up to 255 loops but we will reach this limit.

The idea is to embed to loop itself in a device mapper add-on like dm-crypt, so we won't use any /dev/loop* .

Do you think this is stupid or is there some possility out there ?
(we would like to have some advice before starting any project in this direction)

Thank you,
David G.M.

PS:
Anniversary of this post, one year ago !
http://www.redhat.com/archives/dm-devel/2005-October/msg00031.html
------=_Part_11298_30099163.1160058414050-- --===============0479858206== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============0479858206==-- From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alasdair G Kergon Subject: Re: device mapper integrated loops - and one more year ! Date: Thu, 5 Oct 2006 20:40:05 +0100 Message-ID: <20061005194005.GO17654@agk.surrey.redhat.com> References: <2c53b31c0610050726o47e6784en417de93b98d15e50@mail.gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <2c53b31c0610050726o47e6784en417de93b98d15e50@mail.gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On Thu, Oct 05, 2006 at 04:26:54PM +0200, David Guyon Martin wrote: > Do you think dm could have a loop target instead of seting loops with > losetup ? Something like: http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-loop.patch now perhaps? (And there are patches for dmsetup to become a drop-in losetup replacement.) Alasdair -- agk@redhat.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David Guyon Martin" Subject: Re: device mapper integrated loops - and one more year ! Date: Fri, 6 Oct 2006 11:38:12 +0200 Message-ID: <2c53b31c0610060238nef13171ma6f4a42ba755c3b0@mail.gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids On Thu, 5 Oct 2006 20:40:05 +0100 Alasdair G Kergon wrote: >Something like: > http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-loop.patch >now perhaps? >(And there are patches for dmsetup to become a drop-in losetup replacement.) Yes! This patch add a new file to the kernel tree, dm-loop.c: "This implements a loopback target for device mapper allowing a regular file to be treated as a block device." Great !!! At last :) It seems this dm-loop is quite new, less than a month... As I understand it I need kernel 2.6.18-rc7 to use it, right ? I really thank you a lot for your quick answer and link. Does anyone has yet a feedback about this dm-loop ? David G.M. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan E Brassow Subject: Re: device mapper integrated loops - and one more year ! Date: Mon, 9 Oct 2006 17:36:40 -0500 Message-ID: <950bd3ad1504b8fb03e73b6236a808bc@redhat.com> References: <2c53b31c0610060238nef13171ma6f4a42ba755c3b0@mail.gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 (Apple Message framework v624) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <2c53b31c0610060238nef13171ma6f4a42ba755c3b0@mail.gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On Oct 6, 2006, at 4:38 AM, David Guyon Martin wrote: > On Thu, 5 Oct 2006 20:40:05 +0100 Alasdair G Kergon wrote: > >> Something like: >> >> http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/ >> editing/dm-loop.patch >> now perhaps? > >> (And there are patches for dmsetup to become a drop-in losetup >> replacement.) > > Yes! This patch add a new file to the kernel tree, dm-loop.c: > "This implements a loopback target for device mapper allowing a regular > file to be treated as a block device." > > Great !!! At last :) > It seems this dm-loop is quite new, less than a month... > As I understand it I need kernel 2.6.18-rc7 to use it, right ? > > I really thank you a lot for your quick answer and link. > > Does anyone has yet a feedback about this dm-loop ? > I know Heinz Mauelshagen has been looking at it and already has some performance improvements. Perhaps he'll post the updated patches soon. brassow From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heinz Mauelshagen Subject: Re: device mapper integrated loops - and one more year ! Date: Tue, 10 Oct 2006 20:37:45 +0200 Message-ID: <20061010183745.GA7049@redhat.com> References: <2c53b31c0610060238nef13171ma6f4a42ba755c3b0@mail.gmail.com> <950bd3ad1504b8fb03e73b6236a808bc@redhat.com> Reply-To: mauelshagen@redhat.com, device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <950bd3ad1504b8fb03e73b6236a808bc@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On Mon, Oct 09, 2006 at 05:36:40PM -0500, Jonathan E Brassow wrote: > > On Oct 6, 2006, at 4:38 AM, David Guyon Martin wrote: > > >On Thu, 5 Oct 2006 20:40:05 +0100 Alasdair G Kergon wrote: > > > >>Something like: > >> > >>http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/ > >>editing/dm-loop.patch > >>now perhaps? > > > >>(And there are patches for dmsetup to become a drop-in losetup > >>replacement.) > > > >Yes! This patch add a new file to the kernel tree, dm-loop.c: > >"This implements a loopback target for device mapper allowing a regular > >file to be treated as a block device." > > > >Great !!! At last :) > >It seems this dm-loop is quite new, less than a month... > >As I understand it I need kernel 2.6.18-rc7 to use it, right ? > > > >I really thank you a lot for your quick answer and link. > > > >Does anyone has yet a feedback about this dm-loop ? > > > > I know Heinz Mauelshagen has been looking at it and already has some > performance improvements. Perhaps he'll post the updated patches soon. Yes, I'm settling the changes, which optimize the linear search in the file extents table and the initial lookup of the extents in the file to create the table with the dm-loop author Bryn Reeves right now. First benchmarks show promissing results :-) We hope to post something shortly. Regards, Heinz -- The LVM Guy -- > > brassow > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Red Hat GmbH Consulting Development Engineer Am Sonnenhang 11 Storage Development 56242 Marienrachdorf Germany Mauelshagen@RedHat.com PHONE +49 171 7803392 FAX +49 2626 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David Guyon Martin" Subject: Re: device mapper integrated loops - and one more year ! Date: Tue, 10 Oct 2006 22:11:27 +0200 Message-ID: <2c53b31c0610101311x6bd97cd3n45d2d941f79c1d2a@mail.gmail.com> References: <2c53b31c0610060238nef13171ma6f4a42ba755c3b0@mail.gmail.com> <950bd3ad1504b8fb03e73b6236a808bc@redhat.com> <20061010183745.GA7049@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20061010183745.GA7049@redhat.com> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: mauelshagen@redhat.com, device-mapper development List-Id: dm-devel.ids 2006/10/10, Heinz Mauelshagen : > On Mon, Oct 09, 2006 at 05:36:40PM -0500, Jonathan E Brassow wrote: > > > > On Oct 6, 2006, at 4:38 AM, David Guyon Martin wrote: > > > > >On Thu, 5 Oct 2006 20:40:05 +0100 Alasdair G Kergon wrote: > > > > > >>Something like: > > >> > > >>http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/ > > >>editing/dm-loop.patch > > >>now perhaps? > > > > > >>(And there are patches for dmsetup to become a drop-in losetup > > >>replacement.) > > > > > >Yes! This patch add a new file to the kernel tree, dm-loop.c: > > >"This implements a loopback target for device mapper allowing a regular > > >file to be treated as a block device." > > > > > >Great !!! At last :) > > >It seems this dm-loop is quite new, less than a month... > > >As I understand it I need kernel 2.6.18-rc7 to use it, right ? > > > > > >I really thank you a lot for your quick answer and link. > > > > > >Does anyone has yet a feedback about this dm-loop ? > > > > > > > I know Heinz Mauelshagen has been looking at it and already has some > > performance improvements. Perhaps he'll post the updated patches soon. > > Yes, I'm settling the changes, which optimize the linear search > in the file extents table and the initial lookup of the extents > in the file to create the table with the dm-loop author Bryn Reeves > right now. > > First benchmarks show promissing results :-) > > We hope to post something shortly. > > Regards, > Heinz -- The LVM Guy -- > Thanks a lot ! I stay tuned ( I can hardly wait the results ). I think many sysadmins underestimate the power of loops, more loops and greater performances will ease eyes opening. >From dm-loop, comes dm-stego. I didn't found anything similar in the dev tree. Does anyone know if someone is working on a dm-stego filter ? David G.M. PS: Heinz, since you've written dm-delay, you may have a clue to http://www.redhat.com/archives/dm-devel/2006-October/msg00048.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: devzero@web.de Subject: Re: device mapper integrated loops - and one more year ! Date: Sun, 19 Nov 2006 12:30:05 +0100 Message-ID: <1439173022@web.de> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: quoted-printable Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids Hello ! after desparately seeking for a solution to have more than 256 loop devic= es (for a huge cd-rom server), i have recently come across dm-loop, which= looks very promising (to replace loop.c) can i have more than 256 devices which this? our cd-rom server is going to have more than 256 iso-images soon and i ne= ed to upgrade to a more recent OS, anyway, so this won`t be a problem tha= t dm-loop is so brand new. but - any timeline for dm-loop mainline inclusion ? should i wait for 2.6.19 or 2.6.20 ? is it already useable with less recent kernels, i.e. can i download dm-lo= op patch and recent dmsetup tool and use with older kernel ? i really would like to give it a try - no problem if there are still bugs= inside, because i`d happily test and report if there are bugs left. regards Roland K. systems engineer _______________________________________________________________________ Viren-Scan f=FCr Ihren PC! Jetzt f=FCr jeden. Sofort, online und kostenlo= s. Gleich testen! http://www.pc-sicherheit.web.de/freescan/?mc=3D022222 From mboxrd@z Thu Jan 1 00:00:00 1970 From: devzero@web.de Subject: Re: Re: device mapper integrated loops - and one more year ! Date: Sat, 20 Jan 2007 15:57:23 +0100 Message-ID: <1572893983@web.de> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: quoted-printable Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: breeves@redhat.com Cc: dm-devel@redhat.com List-Id: dm-devel.ids Hello Bryn,=20 >I'll see if we can get a revised version of the current patch for wider >testing in the next couple of weeks - let me know if you would be >interested in trying this out. not sure if i sent a reply to this or have missed this - but, yes - i`m = still interested very much in using dm-loop ! is there anything new with this? do i have to expect issues with files >2gb ? (i need to loopback mount dv= d iso-images) is there a download url for the latest dm-loop patch so i can do some tes= ts and report feedback ? i couldn`t find it at http://sources.redhat.com/cgi-bin/cvsweb.cgi/device= -mapper/?cvsroot=3Ddm and i`m not sure if i should take that one from ht= tp://kernel.org/pub/linux/kernel/people/agk/patches/2.6/ TIA roland > Hello ! >=20 > after desparately seeking for a solution to have more than 256 loop > devices (for a huge cd-rom server), i have recently come across > dm-loop, which looks very promising (to replace loop.c) >=20 > can i have more than 256 devices which this? Hi Roland, Yes, dm-loop will support as many loop devices as device-mapper can allow= . > our cd-rom server is going to have more than 256 iso-images soon and > i need to upgrade to a more recent OS, anyway, so this won`t be a=20 > problem that dm-loop is so brand new. >=20 > but - any timeline for dm-loop mainline inclusion ? >=20 > should i wait for 2.6.19 or 2.6.20 ? There isn't a fixed timeline. We are currently working to improve the lookup code - the prototype patch uses a linear search which doesn't scale well for large/fragmented image files. I have some tests running at the moment and we hope to have something soon - the results so far are good, it's just a case of selecting between a couple of different methods. The changes dm-loop requires in device-mapper core are pretty minor and have already been merged in 2.6.19, so it's just the dm-loop patch itself remaining. > is it already useable with less recent kernels, i.e. can i download > dm-loop patch and recent dmsetup tool and use with older kernel ? This should work fine - there are a couple of known issues with the existing patch, but unless you are using large images (>2G), or have a severely fragmented filesystem you shouldn't run into these. I'll see if we can get a revised version of the current patch for wider testing in the next couple of weeks - let me know if you would be interested in trying this out. Thanks, Bryn. _________________________________________________________________________= _ Erweitern Sie FreeMail zu einem noch leistungsst=E4rkeren E-Mail-Postfach= ! =09 Mehr Infos unter http://freemail.web.de/home/landingpad/?mc=3D021131 From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bryn M. Reeves" Subject: Re: device mapper integrated loops - and one more year ! Date: Mon, 22 Jan 2007 09:43:24 +0000 Message-ID: <45B4873C.8030504@redhat.com> References: <1572893983@web.de> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1572893983@web.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: devzero@web.de Cc: device-mapper development List-Id: dm-devel.ids -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 devzero@web.de wrote: > Hello Bryn, > > >> I'll see if we can get a revised version of the current patch for wider >> testing in the next couple of weeks - let me know if you would be >> interested in trying this out. > > not sure if i sent a reply to this or have missed this - but, yes - i`m still interested very much in using dm-loop ! Hi Roland, No, you've not missed anything! I've got an updated version of the patch with some enhancements Heinz (lvmguy) has been working on to improve the driver's lookup performance. This is still being worked on at the moment. > is there anything new with this? > do i have to expect issues with files >2gb ? (i need to loopback mount dvd iso-images) > > is there a download url for the latest dm-loop patch so i can do some tests and report feedback ? This patch is a little out of date now - I'll get a later version (bugfixes mainly - the new lookup code is still being tested) made available here. Thanks, Bryn. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFFtIcl6YSQoMYUY94RAsRqAJ4iKrXKW5IYe0S9NlUofBp1QpzoiQCgxxba gfoC4jE1+anDhZwz/+MFtUs= =IBSf -----END PGP SIGNATURE-----