[Bug 737027] Re: kpartx udev rule is broken

[Phillip Susi]

The '-part' is an argument to the '-p' switch, so it also needs removed
from the kpartx command, and needs to follow the '-p' switch to dmraid,
if that switch is added there, but I do not think it should be, for the
same reason that it should be removed from kpartx.

The reason that dmraid handles the partitions itself instead of allowing
kpartx to do it is because when it deactivates an array, it must remove
the partitions first, therefore, it must parse the partition tables to
figure out which partitions need removed.  This needs resolved before
the partition handling can be removed from dmraid and kpartx relied on
to do it instead.

Unfortunately, the kernel currently lacks a mechanism to propagate a
removal request or a surprise removal notice up the device stack, which
dmraid would need to properly tear down the dmraid device.  Without
that, it can not properly handle device shutdown without its partition
code ( and can't handle it properly even as it is now, if the partition
is part of LVM ).

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https://bugs.launchpad.net/bugs/737027

Title:
  kpartx udev rule is broken

Status in “dmraid” package in Ubuntu:
  In Progress
Status in “multipath-tools” package in Ubuntu:
  In Progress
Status in “multipath-tools” package in Debian:
  New

Bug description:
  Binary package hint: multipath-tools

  The kpartx udev rule looks like this:

  ENV{DM_STATE}=="ACTIVE", ENV{DM_UUID}=="dmraid-*", \
          RUN+="/sbin/kpartx -a -p -part /dev/$kernel"

  This kpartx command should not be run because dmraid already creates
  the partition device, but it isn't run anyhow because the rule matches
  on "dmraid-*" but dmraid devices have an id of the form "DMRAID-*".
  Note the difference in case.

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