Bug#403687: [david@hardeman.nu: Re: Bug #406697 - Device nodes are not removed when devices are brought down]

Steve Langasek vorlon at debian.org
Mon Jan 15 11:45:41 UTC 2007

severity 403687 important

On Sun, Jan 14, 2007 at 11:08:53PM +0100, David Härdeman wrote:
> I'll forward the same message to this bug that I forwarded to #406697 
> (which is now closed). Feel free to substitute "cryptsetup" for 
> lvm or any other suitable packages in the text below...

This bug report is filed against lvm2, not against cryptsetup?

> udev currently receives uevents from the kernel when a new device-mapper 
> device mapping is created and creates a /dev/dm-* node. libdevmapper 
> knows when devices are created/removed and creates the /dev/mapper/* 
> nodes.

> However, the kernel will not (AFAIK) send uevents when device-mapper 
> mappings are renamed, changed or removed, so udev is not able to remove 
> the devices when appropriate.

> So the "fix" would be to add support for those uevents to the kernel 
> and to change udev to act on them. Ideally it would create the /dev/dm-* 
> devices and symlinks in /dev/mapper/*. 

> Once that is in place, node creation can be removed from libdevmapper 
> (meaning it will have to wait for the nodes to magically appear 
> instead).

> There is a writeup on this with some more details at:
> https://wiki.ubuntu.com/UdevDeviceMapper

> However, I can't see that anything needs to be done in cryptsetup 
> (except making sure that all works when/if this behaviour is changed in 
> libdevmapper).

Ok, between Frans's messages and this one, I don't see any reason we should
consider resolving this bug a blocker for the release.  The most impact
anyone has reported that these not-deleted device nodes have is to generate
some warning messages on shutdown.  Aside from the practical problem of
trying to shove in changes to uevent handling this late, a few messy warning
messages for a particular use case isn't anything that we can't live with.

Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
vorlon at debian.org                                   http://www.debian.org/

More information about the pkg-lvm-maintainers mailing list