On Wed, Jan 16, 2008 at 12:40:06AM +0100, Laurent Vivier wrote: > Le mardi 15 janvier 2008 à 18:27 +0000, Daniel P. Berrange a écrit : > > On Tue, Jan 15, 2008 at 07:22:53PM +0100, Laurent Vivier wrote: > > > As it should be useful to be able to mount partition from a > > > disk image, (and as I need a break in my bug hunting) I've > > > modified the loop driver to mount raw disk image. > > > > > > To not break original loop device, as we have to change minor > > > numbers to manage partitions, a new parameter is added to the module: > > > > I don't see the point in modifying the loop device driver when you > > can already access the partitions with existing device mapper > > functionality & tools. > > There are two reasons: > > 1- I didn't know kpartx (thank you for the tip) > > but using loop device, you will be able to use all partition tables > known by the kernel (acorn, atari, efi, karma, mac, osf, sun, > ultrix, amiga, ibm, ldm, msdos, sgi, sysv68), whereas kpartx can use > only partition tables it knows (bsd, dasd, dos, mac, sun, efi, sun, > unixware).
This is an argument for extending kpartx to cope with the other partition tables :-) I have 50/50 split between VMs using files vs VMs using LVM volumes - the loop driver patches only help you access partitions within a file based image, whereas kpartx can access the partitions within any block device, so can support files (via existing loop device) & LVM vols & nested partitions. > 2- I'd like to mount qcow2 or others disk image formats, so perhaps it's > easier to modify loop device driver (but perhaps you know another magic > tool ?) There has been some work in this area wrt to Xen - the DM-Userspace project had some working code providing a device mapper target calling out to a userspace daemon to handle non-raw file formats like qcow. I don't know what the state of it is now wrt to upstream kernel / device-mapper, or even whether it is more than just 'proof of concept', but the project page is here with some info: http://wiki.xensource.com/xenwiki/DmUserspace Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=| ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel