[Bug 797547] [NEW] os-prober interrupts device connection of kvm machines

[Kaspar Schiess]

Public bug reported:

Binary package hint: os-prober

The reported version of os-prober uses mount to mount all block devices
in our system. Those block devices are connected iSCSI devices that are
used by KVM virtual machines as their root partition. The mount will
perform a read-write mount shortly to fsck the device, crippling the
root partitions this way. This is confirmed by the man page of mount:

              Note that, depending on the filesystem type, state and kernel behavior, the system may still write to  the
              device. For example, Ext3 or ext4 will replay its journal if the filesystem is dirty. To prevent this kind
              of write access, you may want to mount ext3 or ext4 filesystem with "ro,noload" mount options or  set  the
              block device to read-only mode, see command blockdev(8).

Newer versions of the script (I've looked at 1.47) use blockdev --setro
to disable this behaviour. However, doing that will also disable writes
for the KVM machines. The guest operating system will not recover from
this, even after setting blockdev --setrw again.

The proper way to do things would probably be to use the '-o ro,noload'
flag for mount, as documented in the man page and as proposed in the
earlier version of this bug: http://bugs.debian.org/cgi-
bin/bugreport.cgi?bug=556739

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: os-prober 1.38
ProcVersionSignature: Ubuntu 2.6.32-26.48-server 2.6.32.24+drm33.11
Uname: Linux 2.6.32-26-server x86_64
Architecture: amd64
Date: Wed Jun 15 09:02:56 2011
InstallationMedia: Ubuntu-Server 10.04 LTS "Lucid Lynx" - Release amd64 (20100427)
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: os-prober

** Affects: os-prober (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug lucid

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https://bugs.launchpad.net/bugs/797547

Title:
  os-prober interrupts device connection of kvm machines

Status in “os-prober” package in Ubuntu:
  New

Bug description:
  Binary package hint: os-prober

  The reported version of os-prober uses mount to mount all block
  devices in our system. Those block devices are connected iSCSI devices
  that are used by KVM virtual machines as their root partition. The
  mount will perform a read-write mount shortly to fsck the device,
  crippling the root partitions this way. This is confirmed by the man
  page of mount:

                Note that, depending on the filesystem type, state and kernel behavior, the system may still write to  the
                device. For example, Ext3 or ext4 will replay its journal if the filesystem is dirty. To prevent this kind
                of write access, you may want to mount ext3 or ext4 filesystem with "ro,noload" mount options or  set  the
                block device to read-only mode, see command blockdev(8).

  Newer versions of the script (I've looked at 1.47) use blockdev
  --setro to disable this behaviour. However, doing that will also
  disable writes for the KVM machines. The guest operating system will
  not recover from this, even after setting blockdev --setrw again.

  The proper way to do things would probably be to use the '-o
  ro,noload' flag for mount, as documented in the man page and as
  proposed in the earlier version of this bug: http://bugs.debian.org
  /cgi-bin/bugreport.cgi?bug=556739

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: os-prober 1.38
  ProcVersionSignature: Ubuntu 2.6.32-26.48-server 2.6.32.24+drm33.11
  Uname: Linux 2.6.32-26-server x86_64
  Architecture: amd64
  Date: Wed Jun 15 09:02:56 2011
  InstallationMedia: Ubuntu-Server 10.04 LTS "Lucid Lynx" - Release amd64 (20100427)
  ProcEnviron:
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: os-prober

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