On 05/12/2015 01:41 PM, Andrei Borzenkov wrote: > That's what mean - this is direct parent-child. But consider > > bor@opensuse:~/build/grub> echo 0 2048 linear /dev/loop0 0 | sudo dmsetup > create whole > bor@opensuse:~/build/grub> echo 0 59392 linear /dev/loop0 2048 | sudo dmsetup > create part > > At this point /dev/mapper/part refers to partition of /dev/mapper/whole > but there is not direct relationships between two that you can > easily discover > > bor@opensuse:~/build/grub> sudo dmsetup ls --tree > whole (254:5) > └─ (7:0) > part (254:6) > └─ (7:0) > > and > > bor@opensuse:~/build/grub> sudo ./grub-probe -t hints_string -m device.map > /mnt > ./grub-probe: warning: unknown device type loop0 > . > > bor@opensuse:~/build/grub> cat device.map > (hd0) /dev/mapper/whole > > but > > bor@opensuse:~/build/grub> sudo ./grub-probe -t hints_string -m device.map > /mnt > ./grub-probe: warning: unknown device type loop0 > . > --hint='hd0,msdos1' > bor@opensuse:~/build/grub> cat device.map > (hd0) /dev/loop0 > > So in common cases it will work and is better as nothing, but there will be > corner cases that may fail.
Thanks for that explanation. I understand that some relations may be hard to impossible to detect. The cases that I have are plain parent-child relations, though. It would rock the house to get these cases covered again. (On a side note, text "unknown device type loop0" looks like a bug to me since "loop0" is not a type.) >>> Half working solution would be to assume that it is always child map. >>> >>> Or you can take shortcut and assume that /dev/mapper/XXXXpY is >>> partition of /dev/mapper/XXX but you still will need to verify it. >>> >>> Patches are welcome. >> >> I am still wondering: how come it was working in GRUB 2.00 but now >> longer is? >> > > But by you said in previous message that HEAD works? Not sure how > though :) That referred to the '(hd0)'-parameter-with-device-map case, only. This patch to grml-debootstrap says best what has stopped working: https://github.com/hartwork/grml-debootstrap/commit/a705ff45c2d053b0d90ec51700e2d25a760106f3 Best, Sebastian _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel