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On 2016-02-25T14:04:19+00:00 Peter wrote:

This rule may be problematic:

SUBSYSTEM=="block", KERNEL!="ram*",
ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", ENV{SYSTEMD_READY}="0"

The "SYSTEMD_READY=0" will cause automatic unmount of mountpoint that is
on top of such DM device. It's even more problematic if this is used
with multipath which sets DM_UDEV_DISABLE_OTHER_RULES_FLAG in case we
have a CHANGE event that comes after DM multipath device reload when one
of the paths is down or up (see also bug #1310022).

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/0

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On 2016-02-25T19:01:04+00:00 Ryan wrote:

(In reply to Peter Rajnoha from comment #0)
> This rule may be problematic:
> 
> SUBSYSTEM=="block", KERNEL!="ram*",
> ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", ENV{SYSTEMD_READY}="0"
> 
> The "SYSTEMD_READY=0" will cause automatic unmount of mountpoint that is on
> top of such DM device. It's even more problematic if this is used with
> multipath which sets DM_UDEV_DISABLE_OTHER_RULES_FLAG in case we have a
> CHANGE event that comes after DM multipath device reload when one of the
> paths is down or up (see also bug #1310022).

Hi Peter. Glad to hear that this has been identified as a problem.
Obviously I wouldn't normally edit /usr/lib/udev/rules.d/*.rules files
(I know changes will be reverted on update of systemd; perhaps it works
like systemd unit files and I could put an override file of the same
name in /etc/udev/rules.d?) but if I comment out that rule in
99-systemd.rules, is it sufficient to run `udevadm control --reload` to
avoid being bitten by this issue?

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/1

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On 2016-02-26T07:58:08+00:00 Peter wrote:

(In reply to Ryan Sawhill from comment #1)
> Hi Peter. Glad to hear that this has been identified as a problem. Obviously
> I wouldn't normally edit /usr/lib/udev/rules.d/*.rules files (I know changes
> will be reverted on update of systemd; perhaps it works like systemd unit
> files and I could put an override file of the same name in
> /etc/udev/rules.d?) but if I comment out that rule in 99-systemd.rules, is
> it sufficient to run `udevadm control --reload` to avoid being bitten by
> this issue?

Yes, you can comment out that rule for now in
/lib/udev/rules.d/99-systemd.rules and then on next systemd update, this
will be overwritten by the new rules file which will have this removed
officially.

And yes, udevadm control --reload should suffice.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/2

------------------------------------------------------------------------
On 2016-02-26T08:19:01+00:00 Peter wrote:

However, I missed one point - we still need to be sure that systemd
doesn't consider the device to be ready on ADD event because on ADD
event, any DM device is still not ready - it needs to be loaded with
teable and then resumed. So the rule should be:

UBSYSTEM=="block", ACTION=="add",
ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", ENV{SYSTEMD_READY}="0"

(so it checks against 'ACTION=="add"')

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/3

------------------------------------------------------------------------
On 2016-02-26T08:33:36+00:00 Peter wrote:

*** Bug 1300453 has been marked as a duplicate of this bug. ***

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/4

------------------------------------------------------------------------
On 2016-02-26T08:38:11+00:00 Peter wrote:

*** Bug 1310022 has been marked as a duplicate of this bug. ***

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/5

------------------------------------------------------------------------
On 2016-02-26T14:37:05+00:00 Ryan wrote:

Awesome! So to summarize for anyone following this from home, until new
systemd packages including this fix are shipped, you can protect
yourself from this issue by tweaking that line with sed:

  sed -i '/DM_UDEV_DISABLE_OTHER_RULES_FLAG/s|.*|SUBSYSTEM=="block",
KERNEL!="ram*", ACTION=="add",
ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", ENV{SYSTEMD_READY}="0"|'
/usr/lib/udev/rules.d/99-systemd.rules

And reloading the rules:

  udevadm control --reload

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/6

------------------------------------------------------------------------
On 2016-02-26T19:29:05+00:00 Matt wrote:

Can you identify how far back this erroneous rule was introduced?

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/7

------------------------------------------------------------------------
On 2016-02-29T07:39:50+00:00 Lukáš wrote:

https://github.com/systemd/systemd/commit/b7cf1b68a79833411851fa547ac9b4906207c224

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/8

------------------------------------------------------------------------
On 2016-02-29T08:36:41+00:00 Peter wrote:

The systemd rule dates back to 2011 - so very old. But this had not
manifested till we added further rules for multipath where we set flags
for events which are coming from multipath device reload if multipath
component underneath is down or it comes up (and hence multipath device
needs to be reloaded). This is kind of event for which we really don't
need to trigger all the existing rules again and trigger all scanning -
it's just for the multipath dm device table reload which is transparent
to any layer above or any mpath device user - so that's why we added
DM_UDEV_DISABLE_OTHER_RULES_FLAG for such an event - to minimize the
resource usage (in this case udev rule processing).

These new rules in multipath were added in RHEL7.0 then (which is also 2
years already!).

This problem has not manifested yet for other dm-based devices (like
LVM) because these ones don't use the DM_UDEV_DISABLE_OTHER_RULES_FLAG
after the device is set up and running - these require the scans and
rules to be reevaluated if there's any reload compared to the multipath
device where the content of the device is not changed during reloads
when one of the paths is down or up.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/9

------------------------------------------------------------------------
On 2016-03-01T14:50:21+00:00 Lukáš wrote:

pushed to staging ->
https://github.com/lnykryn/systemd-rhel/commit/d77ced281c6d1f47b5dfc3abff6817d8f5756af9
-> post

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/10

------------------------------------------------------------------------
On 2016-04-11T09:02:29+00:00 Martin wrote:

Please send such changes upstream too -- done in
https://github.com/systemd/systemd/pull/3013 now.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/14

------------------------------------------------------------------------
On 2016-04-11T11:07:20+00:00 Lukáš wrote:

Just for reference, here is the original pull request
https://github.com/systemd/systemd/pull/2747

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/16

------------------------------------------------------------------------
On 2016-11-04T00:52:10+00:00 errata-xmlrpc wrote:

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2216.html

Reply at:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1565969/comments/22


** Changed in: systemd (Fedora)
       Status: Unknown => Fix Released

** Changed in: systemd (Fedora)
   Importance: Unknown => High

-- 
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1565969

Title:
  Udev rule causes automatic incorrect unmount of dm device

Status in systemd package in Ubuntu:
  Fix Released
Status in systemd package in Fedora:
  Fix Released

Bug description:
  1) The release of Ubuntu you are using, via 'lsb_release -rd'

  Description: Ubuntu Xenial Xerus (development b ranch)
  Release: 16.04

  2) The version of the package you are using, via 'apt-cache policy
  pkgname'

  systemd:
    Installed: 229-3ubuntu1
    Candidate: 229-3ubuntu1

  3) What you expected to happen

  I am testing our E-Series Netapp storage array and the ability of the
  server to failover IO to the secondary path.  I pull a cable and allow
  DM-MP to fail the path and route IO down the other path.  I then
  replug the cable and repeat for the other path.

  I expect that the failover to occur and for the mount points to stay
  mounted through the operation.

  4) What happened instead

  I see in the system log that during the test systemd tries to perform
  an unmount operation on the mountpoint of the dm-device(s) that have
  lost an underlying path.  The unmount fails, I assume because there is
  active IO at the time.  However it should not be attempted in the
  first place.

  I believe this is related to the bug that we discovered in RHEL and
  SLES that can be seen in this redhat commit:

  https://github.com/lnykryn/systemd-
  rhel/commit/d77ced281c6d1f47b5dfc3abff6817d8f5756af9

  Our testing of RHEL seems to indicate that this patch resolved our
  problem.

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: systemd 229-3ubuntu1
  ProcVersionSignature: Ubuntu 4.4.0-16.32-generic 4.4.6
  Uname: Linux 4.4.0-16-generic x86_64
  ApportVersion: 2.20-0ubuntu3
  Architecture: amd64
  Date: Mon Apr  4 13:56:35 2016
  MachineType: Dell Inc. PowerEdge R720
  ProcEnviron:
   TERM=xterm
   SHELL=/bin/bash
   PATH=(custom, no user)
   LANG=en_US
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-16-generic 
root=UUID=ab1330f8-0a76-4ba4-b2a2-a55f2b68b8c0 ro quiet splash vt.handoff=7
  SourcePackage: systemd
  SystemdDelta:
   [EXTENDED]   /lib/systemd/system/systemd-timesyncd.service -> 
/lib/systemd/system/systemd-timesyncd.service.d/disable-with-time-daemon.conf
   [EXTENDED]   /lib/systemd/system/rc-local.service -> 
/lib/systemd/system/rc-local.service.d/debian.conf
   
   2 overridden configuration files found.
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 01/22/2016
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: 2.5.4
  dmi.board.name: 0VWT90
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A02
  dmi.chassis.type: 23
  dmi.chassis.vendor: Dell Inc.
  dmi.modalias: 
dmi:bvnDellInc.:bvr2.5.4:bd01/22/2016:svnDellInc.:pnPowerEdgeR720:pvr:rvnDellInc.:rn0VWT90:rvrA02:cvnDellInc.:ct23:cvr:
  dmi.product.name: PowerEdge R720
  dmi.sys.vendor: Dell Inc.

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