linux-lvm.redhat.com archive mirror
 help / color / mirror / Atom feed
From: Martin Wilck <mwilck@suse.de>
To: suscricions@gmail.com, systemd-devel@lists.freedesktop.org
Cc: linux-lvm@redhat.com
Subject: Re: [linux-lvm] [systemd-devel] Possible race condition with LVM activation during boot
Date: Thu, 07 Feb 2019 22:51:17 +0100	[thread overview]
Message-ID: <c27673ee58cb15cfd0533bd3bb3f3379e57ca6c8.camel@suse.de> (raw)
In-Reply-To: <20190207191302.1b1dcadd@gmail.com>

On Thu, 2019-02-07 at 19:13 +0100, suscricions@gmail.com wrote:
> El Thu, 7 Feb 2019 11:18:40 +0100
> 
> There's been a reply in Arch Linux forums and at least I can apply
> some
> contingency measures. If it happens again I will provide more info
> following your advice.

The log shows clearly that the device was available first:

feb 06 12:07:09 systemd[1]: Starting File System Check on /dev/disk/by-uuid/cabdab31-983b-401f-be30-dda0ae462080...
feb 06 12:07:09 systemd-fsck[520]: multimedia: limpio, 1051/953984 ficheros, 193506294/244189184 bloques
feb 06 12:07:09 systemd[1]: Started File System Check on /dev/disk/by-uuid/cabdab31-983b-401f-be30-dda0ae462080.

That wouldn't be possible without the device being visible to the system.
Shortly after you get

feb 06 12:07:09 mount[544]: mount: /mnt/multimedia: el dispositivo especial /dev/disk/by-uuid/cabdab31-983b-401f-be30-dda0ae462080 no existe.

... So the device that had already been visible must have disappeared temporarily.
After the mount failure, we see messages about the LV becoming active:

[...]
feb 06 12:07:09 lvm[483]:   1 logical volume(s) in volume group "storage" now active
[...]
feb 06 12:07:09 lvm[494]:   1 logical volume(s) in volume group "storage" now active

There are two "lvm pvscan" processes (483 and 494) that may be interfering 
with each other and/or with the "mount" process. These processes are running 
on 8:17 (/dev/sdb1) and 254:1. I couldn't figure out from your logs what this latter
device might be. 

Wild guess: the pvscan processes working on the VG while it's already
visible are causing the device to get offline for a short time span,
and if the mount is attempted in that time window, the error occurs.

There's another lvm process (340) started earlier by the lvm2-monitor
unit ("Monitoring of LVM2 mirrors, snapshots etc. using dmeventd or
progress polling."). Immediately after termination of this process, the
device seems to be detected by systemd and the above fsck/mount
sequence begins, while the pvscan processes are still running. "lvm2-
monitor.service" runs "vgchange --monitor y". It almost looks as if
this had caused the devices to be visible by systemd, but that would be
wrong AFAICT.

Can you reproduce this with "udev.log-priority=debug"?

Regards,
Martin

  reply	other threads:[~2019-02-07 21:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190206183841.69e38617@gmail.com>
2019-02-07 10:18 ` [linux-lvm] [systemd-devel] Possible race condition with LVM activation during boot Peter Rajnoha
2019-02-07 18:13   ` suscricions
2019-02-07 21:51     ` Martin Wilck [this message]
2019-02-08 13:12       ` suscricions

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=c27673ee58cb15cfd0533bd3bb3f3379e57ca6c8.camel@suse.de \
    --to=mwilck@suse.de \
    --cc=linux-lvm@redhat.com \
    --cc=suscricions@gmail.com \
    --cc=systemd-devel@lists.freedesktop.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).