[Bug 833891] Re: lvscan often times out during boot

[Alex Lyakas]

Hi Serge,
the main thing that lvchange -ay does is activating the LVs within VGs.

After uninstalling the ubuntu LVM package, and installing an official one
(without ubuntu's udev rule), we had to add a call to lvm_lv_activate() for
each LV. So when an existing VG comes up, it is required to go over its LVs
and activate them. But in our case, we don't have LVM on boot drives; and I
am not sure how to trigger LVM LV activation in this case.

Activating the LVs (that ubuntu's rule does) is perhaps not a bad thing. But
the problem is that this is done within the context of udev event
processing, which may cause the udev event processing to get stuck.

BTW, if what I am saying doesn't make sense, that's fine. I am just
reporting the issues that we have experienced.

Thanks,
  Alex.


On Fri, Sep 23, 2011 at 6:00 PM, Serge Hallyn <833891 at bugs.launchpad.net>wrote:

> I took a look a the newest LVM package.  It has a udev rules file, 11
> -dm-lvm.rules, which looks like it should do fine to create the symlinks
> for valid lvs.  Does vgchange -ay do more than that?  Here is the file:
>
> # Copyright (C) 2009 Red Hat, Inc. All rights reserved.
> #
> # This file is part of LVM2.
>
> # Udev rules for LVM.
> #
> # These rules create symlinks for LVM logical volumes in
> # /dev/VG directory (VG is an actual VG name). Some udev
> # environment variables are set (they can be used in later
> # rules as well):
> #   DM_LV_NAME - logical volume name
> #   DM_VG_NAME - volume group name
> #   DM_LV_LAYER - logical volume layer (blank if not set)
>
> # "add" event is processed on coldplug only!
> ACTION!="add|change", GOTO="lvm_end"
> ENV{DM_UDEV_RULES_VSN}!="?*", GOTO="lvm_end"
> ENV{DM_UUID}!="LVM-?*", GOTO="lvm_end"
>
> # Use DM name and split it up into its VG/LV/layer constituents.
> IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup splitname --nameprefixes
> --noheadings --rows $env{DM_NAME}"
>
> ENV{DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG}=="1", GOTO="lvm_end"
>
> # Do not create symlinks for inappropriate subdevices.
> ENV{DM_LV_NAME}=="pvmove?*|?*_vorigin", GOTO="lvm_disable"
> ENV{DM_LV_LAYER}=="?*", GOTO="lvm_disable"
>
> # Create symlinks for top-level devices only.
> ENV{DM_VG_NAME}=="?*", ENV{DM_LV_NAME}=="?*",
> SYMLINK+="$env{DM_VG_NAME}/$env{DM_LV_NAME}", GOTO="lvm_end"
>
> LABEL="lvm_disable"
> ENV{DM_UDEV_DISABLE_DISK_RULES_FLAG}="1"
> ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}="1"
> OPTIONS:="nowatch"
>
> LABEL="lvm_end"
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/833891
>
> Title:
>  lvscan often times out during boot
>
> To manage notifications about this bug go to:
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https://bugs.launchpad.net/bugs/833891

Title:
  lvscan often times out during boot

Status in “udev” package in Ubuntu:
  Confirmed

Bug description:
  I'm not 100% certain that mountall is the problem, but seems a good
  place to start.

  I have some LVM partitions on my laptop, and some filesystems on there
  are mounted through fstab:

  /dev/schroots/schroots /srv/devel ext3 defaults,relatime 0 0
  /dev/schroots/isos /iso ext4 defaults,relatime 0 0

  Often (1/3 of the time?) boot hangs, and after a minute or so I get a
  message saying something about watershed and lvscan timing out.  Then
  it proceeds to mount everything readonly.

  Other times boot proceeds with no problem.

  ProblemType: Bug
  DistroRelease: Ubuntu 11.10
  Package: mountall 2.31
  ProcVersionSignature: Ubuntu 3.0.0-9.12-generic 3.0.3
  Uname: Linux 3.0.0-9-generic x86_64
  NonfreeKernelModules: nvidia
  Architecture: amd64
  Date: Thu Aug 25 10:56:52 2011
  InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110627.1)
  ProcEnviron:
   PATH=(custom, user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: mountall
  UpgradeStatus: No upgrade log present (probably fresh install)

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