Hi Arno,
as an addition, kpartx (not partx) should be able to do that aswell.
It will however not tell the kernel about partitions on a device, but
rather setup dm mappings for each partition.
Just wanted to add this in. And I am somehwat surprised that partprobe
actually works this way. That makes me wonder, why the kernel does
detect partitions on physical disks, but not on other block devices (be
it the current case, or NBDs, iSCSI BDs or whatever)? Does the kernel
simply decide to only scan 'real' block devices by itself. Because it
does so even after boot, when a disk comes up by hotplugging etc. .
Regards
-Sven
Am 18.06.2017 um 17:40 schrieb Arno Wagner:
Hi Julio,
the partitions do not show up on reboot as the kernel cannot
see them. The partition table it would need to scan is
in the encrypted LUKS container and as that is still
closed on boot, hence the kernel has no chance to look at it.
A fix might be to just call "partprobe" after opening the
LUKS container. That scans all reachable devices for
partition tables. It also works directly after repartitioning,
i.e. without a reboot.
partptobe is part of the parted package (at least on Debian).
Regards,
Arno
On Sun, Jun 18, 2017 at 08:49:33 CEST, Julio Gago wrote:
Hi there!
I'm facing an issue I've been unable to solve by myself. I've been exploring around a lot without success. I'm a newbie in this topic so please accept my apologies if this is a silly question.
I am using cryptsetup 1.6.6 in Ubuntu 16.04 on kernel 4.8.0.
I successfully encrypted a disk with LUKS and then created a couple of partitions and mounted them with:
cryptsetup luksFormat --cipher aes-xts /dev/sdc
cryptsetup luksOpen /dev/sdc sdc
fdisk /dev/mapper/sdc
(created partitions manually)
mkfs.ext4 /dev/mapper/sdc1
mkfs.ext4 /dev/mapper/sdc2
mount /dev/mapper/sdc1 /part1_dmcrypt
mount /dev/mapper/sdc2 /part2_dmcrypt
fdisk gave the usual complaint about updating partition list to kernel, which I ignored and assumed it would be fixed by the next reboot. But it didn't!
After reboot, I can open the luks volume normally:
cryptsetup luksOpen /dev/sdc sdc
cryptsetup status sdc
/dev/mapper/sdc is active and is in use.
type: LUKS1
cipher: aes-xts-plain64
keysize: 256 bits
device: /dev/sdc
offset: 4096 sectors
size: 11719929856 sectors
mode: read/write
And I can see the partitions if I use fdisk:
Disk /dev/mapper/sdc: 5.5 TiB, 6000604086272 bytes, 11719929856 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 2F089102-C3CE-4C64-BA09-A19FCC49CFF8
Device Start End Sectors Size Type
/dev/mapper/sdc-part1 2048 6442452991 6442450944 3T Linux filesystem
/dev/mapper/sdc-part2 6442452992 11719929822 5277476831 2.5T Linux filesystem
However, the kernel does not seem to see the partitions, since the block devices are not present in /dev:
ls -la /dev/mapper
total 0
drwxr-xr-x 2 root root 80 Jun 16 19:07 .
drwxr-xr-x 19 root root 4560 Jun 16 18:38 ..
crw------- 1 root root 10, 236 Jun 16 18:35 control
lrwxrwxrwx 1 root root 7 Jun 17 12:15 sdc -> ../dm-0
So I cannot mount the volumes normally. I tried partx and other methods to tell the kernel about the partitions without success. The corresponding IOCTL calls return with EINVAL error.
Decryption seems to be working alright (since I can see the partitions) and I can in fact mount the volumes doing something like this:
losetup /dev/loop0 /dev/mapper/sdc -o 1048576
mount /dev/loop0 /part1_dmcrypt
The volumes seem to have the right contents. So I am actually ok to
proceed, I have backups of both volumes and the LUKS header.
However, I would like to understand what is wrong and how could I fix the
issue and mount the volumes canonicaly.
Thanks in advance for your help and my apologies if I did anything really
silly :)
Regards,
Julio
_______________________________________________
dm-crypt mailing list
dm-crypt@xxxxxxxx
http://www.saout.de/mailman/listinfo/dm-crypt
_______________________________________________
dm-crypt mailing list
dm-crypt@xxxxxxxx
http://www.saout.de/mailman/listinfo/dm-crypt
