[systemd-devel] Using btrfs subvolumes with systemd

[Florent Peterschmitt]

10 juin 2016 15:31 "Lennart Poettering" <lennart at poettering.net> a écrit:
> On Thu, 09.06.16 20:30, Florent Peterschmitt (florent at peterschmitt.fr) wrote:
> 
>> # udevadm info /dev/mapper/root
>> P: /devices/virtual/block/dm-0
>> N: dm-0
>> E: DEVNAME=/dev/dm-0
>> E: DEVPATH=/devices/virtual/block/dm-0
>> E: DEVTYPE=disk
>> E: DM_UDEV_DISABLE_DISK_RULES_FLAG=1
>> E: DM_UDEV_DISABLE_OTHER_RULES_FLAG=1
>> E: DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG=1
>> E: MAJOR=253
>> E: MINOR=0
>> E: SUBSYSTEM=block
>> E: SYSTEMD_READY=0
> 
> So, the question is why this is set for your device. It could be set
> for two reasons: because the DM rules decide so, or because the btrfs
> rules decide so.
> 
> I am not a DM pro, so I am not going to comment on that, but if
> it's the btrfs udev rules, then it would be this file:
> 
> /usr/lib/udev/rules.d/64-btrfs.rules
> 
> Which sets SYSTEMD_READY=0 in case the btrfs ioctls claim that the
> device isn't ready yet to be mounted.
> 
> That said, I'd still bet the DM setup of yours is hosed, and the btrfs
> stuff works fine. If the DM stuff would work correctly you'd have
> properties like DM_NAME or DM_UUID on the device, but you do not.
> 
> Lennart
> 
> --
> Lennart Poettering, Red Hat

I have no udev rules at all in this initramfs, and as I said in another mail, i'll try with genkernel-next that embeds udev (there is a specific option for that) and do stuff with SYSTEMD_READY.

Florent Peterschmitt