Comment 83 for bug 631795

I am affected by this issue in a slightly other way, but it first appeared since one of the last package updates (maybe one or two weeks ago, a new udev package has been there, too).

Setup: Ubuntun "Oneiric" 11.10 64Bit running a LVM in a LUKS/cryptsetup container.

Issue 1: Randomly appearing warnings while booting which seem not to have any real impact. udev complains about a symlink(?) which could not be moved. (boot.log just got overwritten so i can not provide the exact message) I had the impression udev tried to move some temporary file to its final destination. (I think it has been some /dev/mapper/ or /dev/$volume-group-name/ symlink) (this might be related to Bug #864185)

More critical: Issue 2: Snapshotting a logical volume leads randomly to working snapshots with missing links in /dev/mapper/ and /dev/disk/by-id/ (but a dead symlink from /dev/$volume-group-name/ to /dev/mapper/ get's created ...)
Somehow udev fails to create the symlinks. I monitored the udev events passing by (using udevadm monitor --property). The DEVLINKS property appears to contain valid data, to be more precise, the symlinks i would expect to be created by udev, but those symlinks sometimes simlpy never get created.
LVM creates several devices if it creates a snapshot, but i only experienced problems with the symlink representing the snapshot-device itself, the "$name-real" and "$name-cow" devices get linked the way they should (at least i did not experience problems there, but since i never used those links, maybe i just never observed this behaviour there).

And the syslog shows the same message as reported above: udev complains about
> inotify_add_watch(6, /dev/dm-23, 10) failed: No such file or directory
which is the same message as reported here, BUT: udev issues this message if the snapshot gets removed(!), dm-23 is the snapshot volume which just has been gone.